Glossary

An accreditation body is an independent, government-recognised organisation that assesses and confirms the technical competence of testing, inspection and certification bodies. It ensures that these bodies work in accordance with international standards such as ISO/IEC 17024 or ISO/IEC 17020 and deliver reliable, reproducible results.

Accreditation is a key element of quality assurance, for example in materials testing. In this field, it attests to the competence of laboratories in non-destructive testing methods, for example in accordance with DIN EN ISO 9712.

An activation and placement voucher (AVGS) is a free government-funded support measure provided by the Federal Employment Agency or a Jobcenter. It funds measures such as job application or career coaching, preparation for self-employment, or placement through private employment agencies. As a rule, there is no legal entitlement to this support.

During annealing, components are deliberately heated to specific temperatures and held at defined temperatures for specified periods. They are then cooled in a controlled manner. The aim is to change the material properties, for example by reducing hardness (soft annealing), relieving residual stresses (stress-relief annealing), or producing a uniform, fine microstructure (normalising).

An audit is a systematic review of processes, products or systems to ensure their conformity with standards, guidelines or internal requirements. In materials testing, this may involve checking compliance with DIN EN ISO 9001 (quality management) or DIN EN ISO 17025 (testing laboratories). An audit may be conducted internally by a company's own employees or externally by accredited bodies such as TÜV or DAkkS.

The German Accreditation and Licensing Ordinance for Employment Promotion (AZAV) provides the legal basis for the approval of training providers and labour market service providers in Germany. AZAV approval is mandatory for billing further education, coaching or placement services funded through an education voucher from the Federal Employment Agency or a Jobcenter.

Certification in accordance with DIN EN ISO 9712 demonstrates the practical proficiency of qualified testing personnel. Depending on the method and level, between one and 18 months of practical experience must be documented before an application for certification can be made. Certificates are valid for five years and must then be renewed, with recertification required every ten years.

Continuing education refers to vocational qualification measures that go beyond initial training and serve to update, deepen or broaden specialist knowledge. It is crucial to the competitiveness of specialists and companies.

Continuing education ensures:

• Up-to-date expertise, for example on new standards such as DIN 27201-7.
• Career opportunities: higher qualifications mean better jobs.
• Company competence, for example in accredited testing laboratories.
• Occupational safety, for example through radiation protection instruction.

The specialists at our W.S. TrainingCenter will be pleased to support your continuing vocational education: https://www.werkstoff-service.de/en/w-s-trainingcenter/(opens in new tab).

Coordinate metrology is a precise 3D measurement method that uses coordinate measuring machines (CMMs) to capture the geometric shape of components. A CMM scans the surface using a probe or optical sensors and records millions of measurement points, which are processed into a digital representation of the geometry. Coordinate metrology is relevant to materials testing technicians when checking component geometries after heat treatment or coating. The technology is used for:

• quality control in manufacturing, for example checking the fit of bores,
• comparison with CAD data to analyse deviations,
• reverse engineering, for example reproducing prototypes.

We offer several services in coordinate metrology: https://www.werkstoff-service.de/materialtestcenter/koordinatenmesstechnik/(opens in new tab).

Corrosion damage is the alteration or destruction of a material caused by chemical or electrochemical reactions with its environment. It leads to loss of function, safety risks or high costs, for example in the chemical industry, offshore engineering or medical technology.

Typical types of corrosion include:

• Uniform corrosion, such as rust formation on steel.
• Pitting corrosion: localised attack, for example on stainless steel in chloride-containing environments.
• Stress corrosion cracking: cracks caused by the combined effects of tensile stress and a corrosive environment.
• Intergranular corrosion: attack at grain boundaries, for example in sensitised stainless steel.

Microscopic examination, spectrometry and electrochemical tests are used in damage analysis to identify the causes.

Register for our W.S. Spezial seminar “Technical Damage Analysis – Corrosion (SemTSA2)”: https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/semtsa2/(opens in new tab).

Damage analysis within the meaning of ISO/IEC 17020 is the systematic examination of a failed or damaged component to identify the cause of failure. It is carried out by accredited inspection bodies or damage assessment experts and provides legally sound expert reports for insurers or courts.

Our W.S. ExpertCenter provides expert reports and damage analyses. More information: https://www.werkstoff-service.de/expertcenter/schadensanalyse/(opens in new tab).

Register for our W.S. Spezial seminar “Technical Damage Analysis – Mechanical Damage (SemTSA1)”: https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/semtsa1/(opens in new tab).

Register for our “Fundamentals of Damage Analysis” course: https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/gsa/(opens in new tab).

Destructive testing determines material properties and load limits. It addresses questions such as which material is present, what properties it has and how it can be used, for example in structural designs. Typical workplaces include testing laboratories or the quality department of a metals company or mechanical engineering manufacturer.

Materials testing is a mechanical and technological testing process, i.e. a form of destructive testing (DT), which includes tensile tests and Charpy impact tests, for example.

DIN EN ISO 9712 is the key standard for qualification in non-destructive testing (NDT). It specifies the training content, examination procedures and prerequisites for all commonly used methods.

The standard governs qualification, qualification examinations and certification for various NDT methods at three successive levels:

• Level 1: testing personnel with limited competence.
• Level 2: testing personnel with comprehensive competence to perform a testing task, and inspection supervision with limited competence for testing processes and personnel.
• Level 3: inspection supervision with comprehensive competence for testing processes and personnel.

Training is provided by independent training centres, which are typically monitored by an accredited personnel certification body.

Our NDT training centre offers various courses for qualification in NDT methods. More information: https://www.werkstoff-service.de/en/w-s-trainingcenter/book-courses-and-seminars/?kurs_kategorie=non-destructive-testing-courses.

Documented evidence of industrial experience in materials testing, particularly in non-destructive testing (NDT), demonstrates the prior industrial experience required to obtain personnel certification in accordance with the relevant standard, DIN EN ISO 9712. The required duration depends largely on the testing method and the qualification level sought (Level 1, 2 or 3).

Eddy current testing (ET) is a surface testing method. A testing coil carrying alternating current generates an alternating magnetic field. This field induces an eddy current in the component, which in turn generates an alternating magnetic field. The interaction between the fields allows cracks and other surface defects to be detected.

W.S. Werkstoff Service offers courses in eddy current testing at Level 1 (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/et1/(opens in new tab)) and Level 2 (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/et-2/(opens in new tab)).

An expert report in materials testing is a technically substantiated, independent and legally sound assessment of a component or material by a qualified expert. It is prepared for insurers, for example following damage, for courts, for example in product liability cases, and for companies, for example to approve materials.

An expert report includes:

• Documentation, such as photographs, sketches and test records.
• Analyses, such as the cause of damage or material defects.
• Recommendations, such as repair, replacement or process optimisation.

Expert reports are based on standards, such as DIN 50100 for fatigue tests, and are prepared by accredited experts, for example in accordance with DIN EN ISO/IEC 17024.

Our W.S. ExpertCenter provides expert reports and damage analyses. More information: https://www.werkstoff-service.de/expertcenter/schadensanalyse/.

Fluorescence is a physical phenomenon in which a material absorbs light of a particular wavelength, such as UV excitation light, and immediately emits light of a longer wavelength, usually visible light. In materials testing, this is used in penetrant testing (PT), for example. A fluorescent dye penetrates cracks, causing the defects to glow brightly under UV light.

Fractography analyses fracture surfaces to identify the causes of material failure. It combines macroscopic inspection, for example using stereo microscopes, and microscopic examination, such as scanning electron microscopy (SEM), with materials science expertise.

The aim is to distinguish between ductile fracture, for example due to overload, brittle fracture, for example in ceramics, and fatigue fracture caused by cyclic loading. Typical features include dimples (ductile fracture), cleavage facets (brittle fracture) and stepped patterns (fatigue fracture).

Further education refers to the continuous development of specialists' knowledge and skills to keep pace with technological advances. It is essential in dynamic fields such as materials engineering or non-destructive testing (NDT), for example through courses on new standards, such as DIN EN ISO 9712:2026, or testing methods, such as phased array ultrasonic testing.

Grain boundaries are the interfaces between individual crystallites, or grains, in polycrystalline materials such as metals or ceramics. They form during solidification from the melt or through recrystallisation and have a decisive influence on the material's mechanical, electrical and chemical properties:

• Strength: grain boundaries act as barriers to dislocations (the Hall–Petch effect). The finer the microstructure, the higher the strength.
• Corrosion resistance: impurities or segregated elements, such as chromium in stainless steel, often accumulate at grain boundaries and can lead to intergranular corrosion.
• Diffusion: grain boundaries accelerate the transport of material, for example during heat treatment.

In metallography, grain boundaries are revealed by etching and analysed under a microscope. Their shape, size and distribution provide information about the material's thermal history or deformation processes.

Hardening generally uses targeted heat treatment to increase a component's resistance to external forces. In most cases, the component is heated sufficiently to transform its internal structure. Ferrite is transformed into austenite, which can absorb considerably more carbon. The component is then cooled rapidly (quenched) to prevent a return to the previous structure. Instead, the carbon produces a different, harder structure, such as martensite.

Hardness testing measures the hardness of a material, i.e. its resistance to external force. A standardised, very hard indenter is pressed into the component under specified conditions. The resulting indentation is measured and converted into a hardness value. Different hardness testing methods are used depending on the material and application:

• Rockwell (HRC, HRB) – fast, for metals (DIN EN ISO 6508-1),
• Vickers (HV) – precise, for thin layers,
• Brinell (HBW) – for coarse structures (DIN EN ISO 6506-1).

Register for our “HTP – Hardness Testing” course here: https://www.werkstoff-service.de/en/trainingcenter/kurse-und-seminare-buchen/htp-hardness-testing/.

Heat treatment is a branch of materials engineering. It involves the targeted use of heat, where applicable in combination with mechanical forces or chemical processes, to change the properties of a material. Often only the surface of a part is modified, for example through targeted hardening, although sometimes the entire object is treated.

W.S. Werkstoff Service offers various courses in heat treatment: https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/?kurs_kategorie=kurse-waermebehandlung(opens in new tab).

High-temperature testing examines how materials behave under extreme thermal conditions, such as those encountered in gas turbines, furnace construction or aviation. It includes tensile, creep, fatigue and oxidation tests at temperatures of up to 1,500 °C and above. The aim is to assess strength, toughness and long-term stability under actual service conditions.

Hysteresis, from the Greek hysteros meaning “later”, describes a phenomenon in which the state of a material depends not only on current influences but also on its history. In materials testing, hysteresis is relevant to:

• Mechanical loading: a material deforms under load but does not return completely to its initial state, for example in shape-memory alloys.
• Elastic after-effect: stresses in components decay only slowly.
• Damping properties: materials such as rubber dissipate energy through hysteresis, which is important for vibration dampers.

Hysteresis can accelerate fatigue or cause energy losses. It can be measured using stress–strain diagrams or magnetic hysteresis loops, for example.

An inspection within the meaning of ISO/IEC 17020 is a systematic visual or measurement-based examination of components, installations or processes. The aim is to detect defects, wear or deviations from specific requirements, such as standards and specifications, or general requirements assessed through expert judgement.

In materials testing, this includes:

• visual testing (VT) for cracks, corrosion or deformation,
• dimensional checks, for example using 3D scanners,
• non-destructive testing (NDT), such as ultrasonic testing (UT) or magnetic particle testing (MT).

An inspection body is an independent organisation that checks products, processes or systems for conformity with standards, legislation or customer requirements. Unlike laboratories that solely carry out testing, it also performs assessments, audits and certifications, for example in accordance with ISO/IEC 17020 or DIN EN 1090 for welded structures.

Typical tasks include:

• Quality control in manufacturing, for example of welds and coatings.
• Damage analysis following accidents or material failure.
• Monitoring processes, for example heat treatment in accordance with DIN EN ISO 9712.

Inspection bodies often operate under accreditation, for example from DAkkS, and must act neutrally, competently and confidentially. They are essential for companies seeking market approvals, minimising liability risks and demonstrating compliance with quality standards.

The experts at our inspection body support you worldwide with inspection and conformity assessment services in materials engineering, materials testing and non-destructive testing. Find out more here: https://www.werkstoff-service.de/expertcenter/inspektionsstelle/(opens in new tab).

ISO/IEC 17020 is an international standard defining the requirements for inspection bodies. These are organisations that examine products, processes or systems for conformity with standards, legislation or specifications.

Unlike testing laboratories operating in accordance with ISO/IEC 17025, inspection bodies also carry out assessments, audits and certifications, for example for welded structures (DIN EN 1090), pressure equipment or buildings. The standard requires independence, impartiality and competence, for example through accredited inspectors and documented processes. It forms the basis for accreditation by bodies such as DAkkS and ensures that inspections are recognised worldwide.

ISO/IEC 17025 is the worldwide standard for testing laboratories and specifies how they must demonstrate their technical competence and quality assurance. It applies to all fields, from chemical analysis to materials testing. Accredited laboratories, for example those accredited by DAkkS, may issue official certificates that are recognised internationally. The standard requires:

• traceability of measurement results, for example through calibration in accordance with DIN EN ISO 9001,
• documented procedures for testing and calibration,
• qualified personnel and suitable premises,
• independence from external influences.

Magnetic particle testing (MT) is a testing method for detecting surface defects in ferromagnetic components. The test piece is magnetised by passing a current through it or applying a magnetic field. A testing medium consisting of pre-treated metal particles in suspension is then applied. If a surface defect is present, the particles accumulate along the resulting magnetic flux leakage. These can be made visible using UV lamps. Compared with penetrant testing (PT), magnetic particle testing allows more precise identification of defects, but requires greater technical effort.

Further information on eddy current testing is available here: https://www.werkstoff-service.de/materialpruefung-zfp/wirbelstrompruefung/(opens in new tab).

W.S. Werkstoff Service offers courses in magnetic particle testing at Level 1 (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/mt1/(opens in new tab)) and Level 2 (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/mt2/(opens in new tab)).

A material is a natural or artificially produced substance whose physical, chemical and mechanical properties make it suitable for technical applications. Materials are classified by structure and function:

• Metals, such as steel, aluminium and titanium:
  • Properties: high strength, ductility and electrical conductivity.
  • Applications: mechanical engineering, aviation and construction.
• Plastics, such as polyethylene and polyamide:
  • Properties: lightweight, corrosion-resistant and insulating.
  • Applications: packaging, electronics and medical technology.
• Ceramics, such as aluminium oxide and silicon carbide:
  • Properties: heat-resistant, hard and brittle.
  • Applications: cutting tools, insulators and implants.
• Composites, such as carbon-fibre-reinforced and glass-fibre-reinforced plastics (CFRP and GFRP):
  • Properties: a combination of two or more materials, such as carbon fibre and epoxy resin.
  • Applications: aviation, automotive manufacturing and sports equipment.
• Natural materials, such as wood and cork:
  • Properties: renewable and lightweight, but with limited load-bearing capacity.
  • Applications: furniture manufacturing and insulation materials.

Material testing is the umbrella term for all methods that analyse the properties of materials, from chemical composition to mechanical load-bearing capacity. It includes:

• Destructive testing, such as tensile tests and Charpy impact tests.
• Non-destructive testing (NDT), such as ultrasonic, radiographic and eddy current testing.
• Metallography, such as microstructural analysis and hardness testing.
• Spectroscopy, such as X-ray fluorescence analysis and X-ray emission spectroscopy.

Material testing ensures quality in industries such as mechanical engineering, aviation and power generation and forms the basis for compliance with standards, such as DIN EN ISO 6892 for tensile tests. It is carried out in accredited testing laboratories, for example in accordance with DIN EN ISO/IEC 17025.

Materials science is the science and technology concerned with the development, production, testing and application of materials. It combines physics, chemistry, engineering and computer science and provides a foundation for almost all technical disciplines. Key areas include:

Material structure:

• Atomic structure, including crystal lattices and types of bonding.
• Microstructure, including grain size, phases and inclusions.
• Defects, including dislocations and vacancies.

Material properties:

• Mechanical properties, such as strength, toughness and hardness.
• Thermal properties, such as thermal conductivity and melting point.
• Chemical properties, such as corrosion resistance and reactivity.
• Electrical and magnetic properties, such as conductivity and permeability.

Material processing:

• Primary shaping, such as casting and sintering.
• Forming, such as rolling and forging.
• Separating, such as cutting and grinding.
• Joining, such as welding, soldering and brazing.
• Coating, such as electroplating and PVD.

Materials testing:

• Destructive testing, such as tensile tests and hardness testing.
• Non-destructive testing (UT, RT, PT).
• Metallography, including section preparation and microscopy.

Material applications:

• Component design, including finite element analyses.
• Damage analysis, including the causes of fracture.
• Sustainability, including recycling and life cycle assessment.

Materials testing is a systematic process for determining and evaluating material properties such as chemical composition, strength, conductivity or freedom from defects. It supports quality assurance and the safety assessment of materials, particularly metals, and answers key questions:

• Is the material free from defects, for example free from cracks and homogeneous?
• Does it meet the specified requirements?
• Is it suitable for further processing, sale or use?

Both destructive testing methods, such as tensile tests and hardness testing, and non-destructive testing methods, such as ultrasonic testing and X-ray fluorescence, are used. Materials testing provides the basis for compliance with standards, such as DIN EN ISO 6892 and DIN EN 10002, and ensures the reliability of components in industries such as mechanical engineering, aviation and power generation.

Materials testing technicians are qualified skilled workers in industry who examine samples and workpieces made from various materials, test their physical, chemical or mechanical properties and monitor their quality. The occupation is divided into four specialisations: metals technology, systems technology, heat treatment technology and plastics technology.

Materials testing technicians work in all sectors of industry wherever materials need to be tested, approved and assessed. The work is technical in nature but is not physically strenuous.

Measurement uncertainty is important for evaluating testing methods and test results, for quality control and for conformity decisions. It has technical, economic and, where applicable, legal significance.

The true value of a measurand, such as a length, cannot be determined without stating the measurement uncertainty. All factors, instruments and other elements involved in the measurement contribute to the measurement uncertainty. This defines a range of values within which the true value of the measurement lies with a certain probability.

DAkkS, the German accreditation body, increasingly requires expertise in measurement uncertainty, making relevant knowledge and evidence of seminar attendance highly valuable. We therefore offer the following services relating to measurement uncertainty:

• the article series “Measurement Uncertainty in Practice”,
• training on measurement uncertainty,
• evaluation of testing processes and measurement uncertainty by our inspection body,
• materials testing with meaningful statements of measurement uncertainty by our testing laboratory.

More information is available here: https://www.werkstoff-service.de/en/blog/measurement-uncertainty-in-materials-testing/(opens in new tab).

Metallography is the science and technology of examining metallic microstructures, including the structure, composition and properties of metals and alloys. It combines:

• Specimen preparation (grinding, polishing, etching).
• Microscopy (optical microscopy and scanning electron microscopy, SEM).
• Image analysis to determine grain sizes, phase fractions and inclusions.

We carry out metallographic examinations and microstructural analyses for our customers. More information: https://www.werkstoff-service.de/materialtestcenter/metallographie/(opens in new tab).

Metals are inorganic materials with high electrical and thermal conductivity, strength and formability. They are divided into ferrous metals, such as steel and cast iron, and non-ferrous metals, such as aluminium, copper and titanium.

Metals are enhanced through alloying, for example adding chromium to steel for corrosion resistance, or through heat treatment, such as hardening and annealing. Important testing methods include:

• Spectroscopy, such as X-ray fluorescence analysis to determine chemical composition.
• Metallography, such as microstructural analysis to verify heat treatment.
• Mechanical testing, such as tensile tests to determine strength.

Microanalysis is a branch of materials science concerned with high-resolution analytical methods for examining the chemical composition, structure and properties of materials at the microscopic or nanoscopic level. It provides detailed insights that would not be possible with conventional methods such as spectrometry or metallography. Important methods include:

• Scanning electron microscopy (SEM) with EDX (energy-dispersive X-ray spectroscopy): determines elemental distribution and morphological details down to the nanometre scale.
• Electron probe microanalysis (EPMA): precise determination of trace elements in microstructures.
• Transmission electron microscopy (TEM): examination of crystal structures and defects, such as dislocations.
• X-ray diffraction (XRD): analysis of phase composition and stresses in crystals.

Modular vocational qualifications consist of training units lasting several months, each forming part of a recognised occupation. Each individual unit develops occupational competence and enables entry into the primary labour market. Together, the units cover the entire occupation.

Modular vocational training allows flexible entry and exit points. This enables rapid integration into the labour market while allowing qualifications to be acquired step by step. Those who complete all the training modules for an occupation may be admitted to the IHK skilled worker examination.

W.S. Werkstoff Service has been delivering modular vocational qualification in materials testing with great success since 2019. Participants obtain individual certificates, such as certificates in NDT methods in accordance with ISO 9712, as well as evidence of competence.

More information: https://www.werkstoff-service.de/trainingcenter/berufliche-teilqualifizierung/.

An NDT competence centre in accordance with DIN 27201-7 is a specialist body that issues evidence of competence for personnel in non-destructive testing (NDT), particularly in rail vehicle manufacturing. The standard defines:

• Requirements for NDT personnel, such as weld testing personnel and ultrasonic testing personnel.
• Qualification levels, similar to DIN EN ISO 9712 but specific to the industry.
• Examination content, both theoretical and practical.
• Validity periods and recertification.

Objectives:

• Ensuring testing quality in the rail vehicle industry.
• Harmonising NDT standards in Europe.
• Demonstrating technical competence to operators and supervisory authorities.

Find out more about the services of our NDT competence centre here: https://www.werkstoff-service.de/en/w-s-railwaycenter/competence-centre-for-non-destructive-testing-ndt/(opens in new tab).

Non-destructive testing (NDT) encompasses testing methods that examine materials and components for defects, dimensions or properties without causing damage. It is mandatory in safety-critical industries such as aviation (DIN EN 4179), power generation (DIN EN 12952) and rail transport (DIN 27201).

Important methods include:

• Visual testing (VT) in accordance with DIN EN 13018: surface defects and welds.
• Penetrant testing (PT) in accordance with DIN EN ISO 3452: cracks and pores in metals and plastics.
• Magnetic particle testing (MT) in accordance with DIN EN ISO 9934: surface cracks in ferromagnetic materials.
• Ultrasonic testing (UT) in accordance with DIN EN ISO 16810: internal defects, such as cracks and shrinkage cavities, and wall thickness measurement.
• Radiographic testing (RT) in accordance with DIN EN ISO 17636: volumetric defects, such as slag and pores, and weld evaluation.
• Eddy current testing (ET) in accordance with DIN EN ISO 15548: surface cracks and coating thickness measurement.
• Thermography (TT) in accordance with DIN EN 16714: delamination and corrosion.

NDT is a key field of work for materials testing technicians, with high demand and international certification opportunities, for example in accordance with DIN EN ISO 9712.

W.S. Werkstoff Service offers various services (https://www.werkstoff-service.de/materialtestcenter/zerstoerungsfreie-pruefung/) and courses (https://www.werkstoff-service.de/en/w-s-trainingcenter/book-courses-and-seminars/?kurs_kategorie=non-destructive-testing-courses(opens in new tab)) in non-destructive testing.

Optical emission spectrometry (OES) is a highly precise method for the elemental analysis of metals and alloys. A sample is excited by an electric spark or arc, causing atoms to emit light at characteristic wavelengths. A spectrometer measures these emissions and compares them with reference data to determine the quantitative composition of the material.

Modern instruments are portable and deliver results within seconds. Although the method is destructive, it is extremely accurate and therefore ideally suited to material identification, alloy development and process optimisation.

Penetrant testing (PT) is a surface testing method used to detect cracks or pores. It uses a coloured oil- or water-based testing medium that is drawn into cracks by capillary action. After intermediate cleaning, the penetrant is drawn out by a developer with even stronger capillary action, making defects visible at the surface through colour contrast.

W.S. Werkstoff Service offers courses in penetrant testing at Level 1 (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/pt1/) and Level 2 (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/pt2/).

Phased array ultrasonic testing (PAUT) uses multiple ultrasonic transmitters and receivers arranged in an array. These can be controlled separately to transmit sound through the component from different angles, for example. Unlike conventional UT, which relies on a relatively abstract screen display for evaluation, phased array testing can produce images.

Our “UT2 PA” course is aimed at experienced Level 2 and Level 3 UT testing personnel and inspection supervisors who wish to learn the phased array testing technique. Register here: https://www.werkstoff-service.de/en/trainingcenter/kurse-und-seminare-buchen/ut2-pa-ultraschallpruefung-phased-array/(opens in new tab).

Radiation protection encompasses all measures to protect people and the environment from ionising radiation, such as X-rays, gamma rays and neutrons. It is regulated by law, for example by the German Radiation Protection Act (StrlSchG) and X-ray Ordinance (RöV). Breaches of these regulations can result in harm to health, such as radiation sickness, and legal consequences.

We offer radiation protection training for NDT testing personnel and designated officers in accordance with the technical qualification guideline based on the Radiation Protection Ordinance (StrSchV) and X-ray Ordinance (RöV), as well as training for the transport of dangerous goods (ADR, Class 7). More information is available here: https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/?kurs_kategorie=kurse-strahlenschutz(opens in new tab).

In radiographic testing (RT), also known as radiography, components are exposed to X-rays or gamma rays to reveal internal defects such as shrinkage cavities, pores, cracks or inclusions. This produces a two-dimensional image of the internal structure on a detector or film. It is a non-destructive testing method.

W.S. Werkstoff Service offers courses in radiographic testing at Level 1 (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/rt-f-1/) and Level 2 (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/rt-f-2/).

Railway components such as wheels, axles, rails and brakes are heavily loaded parts that must withstand extreme mechanical, thermal and corrosive forces. Regular inspections and certifications, for example in accordance with DIN 27201-7, are therefore required by law.

Materials testing ensures operational safety through non-destructive testing (NDT), such as ultrasonic testing (UT) of wheelset axles or magnetic particle testing (MT) of welds.

Examples:

• Railway wheels must combine hard surfaces for wear resistance with tough cores for fracture resistance. They are tested in accordance with DIN EN 13262.
• Axles are examined for fatigue cracks, for example using ultrasonic testing.
• Rails must withstand wear and fatigue and are tested in accordance with DIN EN 13674.

Our NDT competence centre (DIN 27201-7) supports companies with non-destructive testing during maintenance, from assessing individual indications to interpreting them in the context of the applicable regulatory framework. More information: https://www.werkstoff-service.de/en/w-s-railwaycenter/competence-centre-for-non-destructive-testing-ndt/.

A railway wheel is a safety-critical component that must withstand extreme loads, such as braking and cornering, as well as wear. It is made of high-strength steel and is tested in accordance with DIN EN 13262. Defective wheels can cause derailments, so regular inspections and certifications, for example in accordance with DIN 27201-7, are required.

Important testing methods include:

• Ultrasonic testing for internal defects, such as shrinkage cavities and cracks.
• Magnetic particle testing (MT) for surface cracks.
• Hardness testing to ensure wear resistance.
• Microstructural analysis to verify heat treatment.

We have also developed a testing concept for the semi-automatic ultrasonic testing of wheelsets: the Wheel Set Scan System (WS3). More information: https://www.werkstoff-service.de/en/w-s-railwaycenter/wheel-set-scan-system-ws3/.

Recertification in non-destructive testing (NDT) in accordance with DIN EN ISO 9712 is generally required ten years after initial certification or five years after a previous renewal to extend the validity of the testing personnel certificate for a further five years.

W.S. Werkstoff Service carries out recertification in ultrasonic testing (UT), magnetic particle testing (MT), penetrant testing (PT), visual testing (VT), eddy current testing (ET) and radiographic testing (RT-F) in accordance with DIN EN ISO 9712 and the guidelines of the German Society for Non-Destructive Testing (DGZfP). More information: https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/?kurs_kategorie=rezertifizierung-zfp-iso-9712(opens in new tab).

Recrystallisation is a thermally activated process in which a deformed metallic microstructure is restructured through the formation of new crystals. It occurs when a material is heated above a certain temperature, the recrystallisation temperature, which is usually 30–50% of its melting temperature. The process involves:

• Nucleation: new, stress-free crystals form in areas of high dislocation density.
• Grain growth: the new grains grow at the expense of the deformed structure.
• Softening: strength decreases and ductility increases.

For materials testing technicians, recrystallisation is relevant when analysing heat treatment defects or optimising manufacturing processes.

Renewal is the process of extending an expiring certificate, for example in accordance with DIN EN ISO 9712 or AZAV, for a further validity period of five years through initial certification or recertification.

W.S. Werkstoff Service conducts renewal examinations in ultrasonic testing (UT), magnetic particle testing (MT), penetrant testing (PT), visual testing (VT), eddy current testing (ET) and radiographic testing (RT-F) in accordance with DIN EN ISO 9712 and the guidelines of the German Society for Non-Destructive Testing (DGZfP).

More information: https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/?kurs_kategorie=erneuerung-zfp-iso-9712.

Research drives the development of materials and testing methods. In materials testing, it focuses on:

• New materials, such as lightweight alloys and composites.
• Innovative testing methods, such as AI-assisted ultrasonic evaluation and phased array technology.
• Optimisation of manufacturing processes, such as additive manufacturing and heat treatment.

Research findings are incorporated into standards, such as DIN, ISO and EN, and industry standards. Collaboration between universities, testing laboratories and industry, for example involving Fraunhofer institutes and BAM, is essential to ensure practical applicability. Examples include research into hydrogen embrittlement in steels and new NDT methods for additive manufacturing.

In collaboration with industrial companies, universities and research institutions, we develop new testing methods, innovative materials, modern sensor and monitoring systems, and forward-looking solutions for quality assurance and maintenance. More information: https://www.werkstoff-service.de/forschung-entwicklung/.

Residual stress measurement determines internal stresses in materials that arise from manufacturing processes such as welding, grinding or hardening. These stresses can cause distortion, cracks or premature failure. Measurement helps to optimise manufacturing processes and extend service life.

W.S. Werkstoff Service offers residual stress measurement: https://www.werkstoff-service.de/materialtestcenter/eigenspannungsmessung/.

We have also developed our own testing system for residual stress measurement, ResiduStress. Find out more here: https://www.werkstoff-service.de/projekt/residustress/.

Residual stresses are mechanical stresses in a material or component that arise without the direct action of external forces. They occur during mechanical deformation, thermal processes or as a result of irregularities in the microstructure.

Unwanted residual stresses, for example after welding, can cause components to distort and must be relieved by targeted heat treatment. In other cases, residual stresses are deliberately introduced, for example to increase surface strength through shot peening.

A sample is a representative piece of material taken so that testing can provide information about the entire component or material. Samples must be homogeneous, free from contamination and correctly dimensioned, otherwise they can distort measurement results. Sampling and specimen preparation follow strict standards, such as DIN EN ISO 377 for tensile samples. An unsuitable sample can lead to incorrect conclusions, for example when releasing batches or investigating damage.

Shrinkage cavities are voids or pores in castings that form as the molten material shrinks during solidification. They impair mechanical properties such as tensile strength and ductility and can cause cracks or leaks. Shrinkage cavities occur when:

• the molten material cools too quickly and a solid shell forms before the interior solidifies,
• gas bubbles are trapped, for example due to insufficient degassing,
• risers, which supply additional molten material, do not provide enough material.

In materials testing, shrinkage cavities are detected using ultrasonic testing (UT), radiographic testing (RT) or metallographic sections.

To examine a material, for example to assess its microstructural properties, a sample generally needs to be prepared. Its surface is ground using progressively finer grit sizes, often with simultaneous water cooling to prevent unintended heat treatment. The sample is then polished. Very small parts are also mounted in synthetic resin or polymer to make them easier to handle.

Spectral analysis is an analytical method used to determine the chemical composition of a material by measuring its spectrum (light or X-ray radiation). It uses the principle that each element absorbs or emits characteristic wavelengths. There are two main methods:
optical emission spectrometry (OES) and X-ray fluorescence analysis (XRF).

W.S. Werkstoff Service offers various services (https://www.werkstoff-service.de/materialtestcenter/spektralanalyse/ (opens in new tab)) and courses (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/spe/ (opens in new tab)) in spectral analysis.

Spectrometry determines the composition of a material by evaluating its spectrum, which is produced through either emission or absorption. Optical emission spectrometry (OES) is frequently used in materials testing. A spark is applied to the material and the radiation emitted by the excited atoms is measured. Another common application is X-ray fluorescence analysis (XRF), in which the sample is excited by X-ray radiation.

Steam sterilizers are devices that sterilise medical instruments, laboratory equipment or packaging using saturated steam under pressure at 121–134 °C. The process destroys bacteria, viruses and spores by denaturing proteins and DNA, making it the most reliable method of killing microorganisms. This is relevant to materials testing technicians when testing materials for biocompatibility or resistance to disinfectants.

More information: https://www.werkstoff-service.de/materialtestcenter/zerstoerungsfreie-pruefung/et-pruefung-von-dampfsterilisatoren/.

Strength is a measure of a material's ability to withstand mechanical loading, or the maximum stress it can withstand during deformation. If this limit is exceeded, the component fails, often through permanent deformation or fracture. Under ideal conditions and within certain limits, components with fatigue strength can withstand an unlimited number of load cycles.

Surface testing
Surface testing is used to detect defects on the surfaces of components, such as cracks, pores or areas of corrosion. It is the first step in non-destructive testing (NDT) and uses various methods:

• Penetrant testing (PT): coloured testing media penetrate cracks and are made visible using a developer.
• Magnetic particle testing (MT): in ferromagnetic materials, metal particles accumulate at magnetic leakage fields above defects.
• Visual testing (VT): optical examination using magnifying glasses, endoscopes or cameras.
• Eddy current testing (ET): induced eddy currents respond to surface defects.
• Stylus profilometry to measure roughness, for example in accordance with DIN EN ISO 4287.
• Dye testing, for example penetrant testing in accordance with DIN EN ISO 3452.
• 3D surface measurement, for example using optical 3D scanners.

More information about our “Preparatory Course in Surface Testing Methods (ORV)” is available here: https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/orv/(opens in new tab).

Tempering generally serves to relieve stresses in a material that have arisen, for example, during hardening. The higher the tempering temperature, the softer the material becomes again. Temperatures of 200 °C and above are generally used, with tempering times ranging from minutes to hours. Tempering is sometimes also carried out for decorative purposes (bluing).

In a tensile test, a flat or round sample is pulled apart under high force while the resulting force and the material's elongation are continuously measured. The result is generally a stress–strain diagram. The sample's behaviour during the test provides information about its yield strength, tensile strength and elongation at fracture. This enables properties such as strength and elasticity to be assessed.

This standard specifies the training and examination of personnel in non-destructive testing (NDT) below Level 1 of ISO 9712. It defines the admission requirements, content, scope and procedures for qualification and the qualification examination for test technicians. Qualification as a test technician is considerably shorter than qualification in accordance with ISO 9712 and includes:

• Fundamentals of testing methods and equipment.
• Handling testing equipment and accessories.
• Testing in accordance with a testing instruction using pre-set equipment.
• Detecting and recording indications.

DIN 54161 also allows company-specific training content to be addressed much more flexibly than the considerably more formalised training in accordance with ISO 9712.

W.S. Werkstoff Service offers various courses for test technicians. More information is available here: https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/?kurs_kategorie=kurse-pruefwerker(opens in new tab).

Testing equipment is a technical measuring instrument used to carry out tests in accordance with standardised methods. It must be calibrated, compliant with standards, such as DIN EN ISO 9712, and suitable for its intended purpose. Testing equipment undergoes regular maintenance and calibration, for example in accordance with DIN EN ISO 17025, to minimise measurement uncertainty. Incorrectly adjusted or defective equipment produces incorrect results.

A testing instruction is a documented work instruction that specifies the procedure, parameters and criteria for a test. It is a mandatory element of ISO/IEC 17025 and ISO 9001 and ensures reproducibility, transparency and legal certainty.

Testing instructions are prepared by accredited laboratories or certification bodies and are binding on testing personnel. They prevent sources of error and enable comparable results, for example in acceptance testing or expert damage reports. A typical testing instruction includes:

• Test objective, for example “Detection of cracks in a weld”.
• Applicable method, for example “DIN EN ISO 17635 for NDT”.
• Equipment and material requirements, for example “Ultrasonic instrument with a 2 MHz probe”.
• Step-by-step instructions.
• Acceptance criteria, for example “No indications > 2 mm”.

A testing laboratory is an accredited facility that carries out material testing, analyses and certifications in accordance with international standards, such as ISO/IEC 17025 or DIN EN ISO 9001. It provides technical equipment, qualified personnel and documented processes to deliver reliable results. Accredited laboratories, for example those certified by DAkkS, may issue official certificates that are recognised internationally. Typical tasks include:

• Destructive testing, such as tensile tests and hardness tests.
• Non-destructive testing (UT, RT, PT, MT).
• Chemical analyses, such as spectrometry, OES and XRF.
• Metallographic examinations, including section preparation and microscopy.
• Damage analyses, including fracture analyses and corrosion investigations.

The experts at our testing laboratory, accredited in accordance with ISO/IEC 17025, support and advise you on all aspects of materials engineering and the materials testing of metals: https://www.werkstoff-service.de/en/materialtestcenter/(opens in new tab).

Ultrasonic testing (UT) is a testing method used to detect defects inside components. A probe transmits a high-frequency sound pulse into the component. Depending on the component geometry and the location of possible defects, the sound echo, or its absence, is evaluated to draw conclusions about potential defects. Evaluation takes place during testing using the display on the testing instrument.

Ultrasonic testing requires trained personnel, for example in accordance with DIN EN ISO 9712 Level 2 or 3.

W.S. Werkstoff Service offers courses in ultrasonic testing at Level 1 (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/ut-1/(opens in new tab)) and Level 2 (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/ut-2/(opens in new tab)).

In visual testing (VT), components are examined optically or visually for surface defects. VT is generally the first step in non-destructive testing, as it allows defects to be found and quality decisions to be made with comparatively little effort. Possible aids include magnifying glasses, endoscopes, videoscopes and cameras.

W.S. Werkstoff Service offers courses in visual testing at Level 1 (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/vt1/(opens in new tab)) and Level 2 (https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/vt2/(opens in new tab)).

Under Section 1(5) of the German Vocational Training Act, vocational retraining is training intended to enable a person to pursue a different occupation. The Chambers of Industry and Commerce (IHK) assess the suitability of training centres to deliver vocational retraining, monitor these centres and are responsible for conducting skilled worker examinations.

W.S. Werkstoff Service offers “2-in-1” vocational retraining in materials testing, combining metals technology and systems technology. Further information: https://www.werkstoff-service.de/en/w-s-trainingcenter/career-change-and-vocational-rehabilitation/vocational-retraining-as-a-materials-testing-technician-in-metals-technology-ihk/(opens in new tab).

Waterjet cutting is a precise cutting process in which an ultra-high-pressure water jet, at pressures of up to 6,000 bar, cuts materials without thermal effects. For materials testing technicians, waterjet cutting is an important specimen preparation method, for example for metallographic sections or ceramic samples. There are two variants:

• Abrasive waterjet cutting, with added garnet sand or corundum: for hard materials such as steel, titanium, ceramics or composites. Cutting width: 0.5–2 mm. Cutting speed: up to 10 m/min, depending on material thickness.
• Pure waterjet cutting: for soft materials such as rubber, plastics or food. Cutting width: 0.1–0.5 mm. Surface quality: Ra ≤ 2.5 µm.

Wear damage results from the progressive removal of material or changes to component surfaces caused by friction, corrosion or abrasive particles. It can lead to loss of function, leaks or fracture. Typical wear mechanisms include:

• Adhesive wear: material transfer between two surfaces, for example in bearings or gears.
• Abrasive wear: material removal by hard particles, for example in conveying systems or pumps.
• Erosive wear: material removal by flowing media, for example in pipelines or turbine blades.
• Corrosive wear: a combination of corrosion and mechanical loading, for example crevice corrosion in welds.

Weld evaluation is a key part of quality assurance in metalworking. It ensures that welded joints are free from defects and able to withstand loading. Possible testing methods include:

• Non-destructive testing (NDT):
  • Visual testing (VT) for pores, undercut or overlap.
  • Magnetic particle testing (MT) for cracks in ferromagnetic materials.
  • Penetrant testing (PT) for non-magnetic metals.
  • Ultrasonic testing (UT) to detect internal cracks or lack of fusion.
  • Radiographic testing (RT) for volumetric defects, such as slag inclusions.
• Destructive testing (DT):
  • Tensile tests to determine strength.
  • Charpy impact tests to determine toughness.
  • Metallography to analyse the microstructure, for example martensite formation.

Further information about our weld evaluation services is available here: https://www.werkstoff-service.de/materialtestcenter/schweissnahtpruefung/(opens in new tab).

Register for our W.S. Spezial seminar “Weld Testing and Evaluation” (SNB seminar):
https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/semsnb/(opens in new tab).

Register for our course “SNB – Destructive and Non-Destructive Weld evaluation”: https://www.werkstoff-service.de/trainingcenter/kurse-und-seminare-buchen/snb/(opens in new tab).

Wheelset axles are heavily loaded railway components that connect wheels and drive shafts in locomotives, multiple units or freight wagons. They are usually made of high-strength quenched and tempered steels, such as 34CrNiMo6, and must withstand extreme dynamic loads, including torsion, bending and vibration.

Wheelset axles are subject to strict approval requirements, such as DIN EN 13261, and are tested regularly to ensure operational safety, for example using:

Non-destructive testing (NDT):

• Ultrasonic testing (UT) to detect internal defects, such as shrinkage cavities and cracks.
• Magnetic particle testing (MT) for surface cracks.
• Visual testing (VT) for corrosion or mechanical damage.

Destructive testing (DT):

• Fatigue tests to determine fatigue strength under service loading.
• Tensile and impact tests to determine material properties.

X-ray emission spectroscopy (XES), also known as X-ray fluorescence analysis (XRF), is a spectroscopic measurement method used in material analysis, physics and chemistry. It examines the X-ray spectrum emitted by a sample after vacancies have been created in the atoms' inner electron shells. XES thus provides precise information about a material's elemental composition, electronic structure and chemical bonding.