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Definition: The calibration of electrical measurands is the documented determination of the relationship between the readings of a measuring instrument and the quantity values realised by traceable standards (e.g. voltage, current, resistance, frequency) under specified conditions. It provides measurement deviations and measurement uncertainties as the basis for reliable measurement results. Requirements regarding competence, traceability, measurement uncertainty evaluation and documentation are specified for calibration laboratories in DIN EN ISO/IEC 17025.

Practical relevance: Calibrated measuring equipment is an essential prerequisite for reliable testing and production data. Calibration provides measurement deviations and measurement uncertainties that are used to assess the suitability of a measuring instrument for a specified tolerance. A statement of conformity is only made if it has been requested and a decision rule has been defined. Traceability to national or international standards (e.g. PTB) is essential for quality assurance, comparability and compliance in regulated industries.

Decision-making perspectives:

• Technical decision-makers: Ensuring correct process and test data.
• Purchasing/project management: Selecting competent (e.g. accredited) calibration laboratories and defining calibration intervals.
• Science: Evaluating measurement uncertainties and validating experimental results.
• Insurance/law: Demonstrating proper monitoring of measuring equipment in the event of a liability claim.

Typical testing or verification methods: Comparison calibration with reference standards, measurement uncertainty calculation, calibration certificate with proof of traceability.

FAQ:

• Why is traceability important in calibration?
• It ensures the international comparability and legal recognition of measurement results.

Definition: The calibration of mechanical measurands is the documented determination of the relationship between the readings of a measuring instrument and the quantity values realised by traceable standards (e.g. force, pressure, torque, length) under defined mechanical and environmental conditions. It provides measurement deviations and measurement uncertainties as the basis for reliable measurement results. Requirements regarding competence, traceability, measurement uncertainty evaluation and documentation are laid down in DIN EN ISO/IEC 17025 for calibration laboratories.

Practical relevance: Calibrated test equipment is an essential prerequisite for valid results in materials testing, production monitoring and quality assurance. Display deviation, repeatability and conformity with specified tolerances are assessed. Traceability is achieved via national standards, e.g. those of the PTB. Uncalibrated measuring instruments can lead to systematic misjudgements and liability risks.

Decision-making perspectives:

• Technical decision-makers: Ensuring correct test forces (e.g. in tensile or hardness testing) and process parameters.
• Purchasing/project management: Selecting accredited calibration service providers and defining risk-based intervals.
• Science: Evaluating the measurement uncertainty and reproducibility of experimental data.
• Insurance/law: Demonstrating proper monitoring of test equipment in the context of product liability.

Typical testing or verification methods: Comparison calibration with force, pressure, torque or length standards, documentation of the traceability chain to national or international standards, issuing of a calibration certificate, where applicable with a conformity statement based on a defined decision rule.

FAQ:

• Which mechanical measurands must be calibrated regularly?
• In particular force, pressure, torque and length measuring instruments in quality-relevant testing and production processes.

Definition: The calibration of thermodynamic measurands is the documented determination of the relationship between the indications of a measuring instrument and the quantity values realised by traceable standards (e.g. temperature, relative humidity, pressure or flow) under defined thermodynamic and ambient conditions. It provides measurement errors and measurement uncertainties as the basis for reliable measurement results. Requirements for competence, traceability, measurement uncertainty assessment and documentation are laid down in DIN EN ISO/IEC 17025 for calibration laboratories.

Practical relevance: Temperature, humidity and pressure measurements are safety- and quality-critical in process plants, laboratories and testing facilities.
Calibration provides measurement errors, stability information and measurement uncertainties that are used to assess the suitability of a measuring device for specified limit values. A statement of conformity is only made if it has been commissioned and is based on a defined decision rule. Traceability is achieved via recognised reference scales and standards (e.g. ITS-90 for temperature or calibrated pressure and climate standards) and is decisive for process safety, product quality and regulatory compliance.

Decision-making perspectives:

• Technical decision-makers: Ensuring correct temperature and pressure control in plants and test rigs.
• Purchasing/project management: Definition of suitable calibration intervals as well as selection of competent, preferably accredited calibration laboratories.
• Science: Assessment of thermodynamic measurement uncertainties, reference scales (e.g. ITS-90) and long-term stability to validate experimental results.
• Insurance/law: Verification of standard-compliant monitoring of measuring equipment including traceability and decision rules in damage or compliance cases.

Typical testing or verification methods: Comparison calibration in temperature baths, furnaces or climate chambers under defined stability and equilibrium conditions, humidity and pressure calibration using traceable reference sensors or standards, determination and documentation of the measurement uncertainty including thermodynamic influencing variables (e.g. gradients, drift, stability), documentation of the traceability chain to recognised reference scales and standards, issuing of a calibration certificate where applicable with a statement of conformity based on a defined decision rule

FAQ:

• Why is temperature calibration safety-relevant?
• Incorrect temperature measurements can lead to overheating, material damage or process instability.

Definition: The Charpy impact bending test is a dynamic testing method for determining the toughness of a material under impact loading. A standardised notched specimen is broken by a pendulum in a sudden impact, with the absorbed impact energy being measured. The procedure is regulated in DIN EN ISO 148-1.

Practical relevance: The determined impact energy (e.g. KV in joules) serves to assess the transition behaviour from ductile to brittle (brittle fracture transition temperature). The test is particularly relevant for pressure equipment, structural steelwork and low-temperature applications. Test temperature, specimen shape (V- or U-notch) and orientation relative to the rolling direction significantly influence the result.

Decision-making perspectives:

• Technical decision-makers: Assessment of low-temperature toughness and selection of suitable materials.
• Purchasing/project management: Specification of required minimum impact energies at defined temperatures.
• Science: Investigation of brittle fracture mechanisms and microstructural influences.
• Insurance/law: Demonstration of sufficient toughness in failure cases relevant to brittle fracture.

Typical testing or verification methods: Charpy V-notch test, temperature series testing, fracture surface analysis in the SEM.

FAQ:

• Why is the Charpy impact bending test carried out at low temperatures?
• To determine the susceptibility to brittle fracture and the transition temperature of the material.

Definition: A coordinate measuring machine (CMM) is a tactile or optical measuring system for the three-dimensional acquisition of a workpiece’s geometric features. It determines coordinate points in space and uses these to calculate dimensions as well as form and position tolerances. The accuracy requirements are governed by DIN EN ISO 10360.

Practical relevance: CMMs are used to inspect complex geometries, positional and profile tolerances within the framework of the GPS standards (e.g. DIN EN ISO 1101). Dimensional deviations, flatness, roundness or positional tolerances are assessed. Measurement uncertainty, temperature stability and calibration status have a decisive influence on the quality of the results.

Decision-making perspectives:

• Technical decision-makers: Ensuring function-critical tolerances and series suitability.
• Purchasing/project management: Definition of inspection plans, acceptance criteria and measurement strategies.
• Science: Analysis of measurement uncertainties and comparison of tactile versus optical systems.
• Insurance/law: Documented geometric verification in disputes over dimensions or fit.

Typical testing or verification methods: 3D point measurement, scanning, evaluation against the CAD data set, measurement report including uncertainty statement.

FAQ:

• Which standard governs the accuracy of a CMM?
• DIN EN ISO 10360 defines test procedures and accuracy requirements for coordinate measuring machines.

Definition: Coating technology comprises processes for the targeted application of functional or protective layers onto material surfaces. The aim is to improve corrosion protection, wear resistance, and electrical or thermal properties. The layer can be metallic, ceramic, polymer-based or designed as a composite system.

Practical relevance: Industrial processes include physical and chemical vapour deposition (PVD, CVD), thermal spraying (DIN EN 657), electroplating, powder coating and painting technology. Layer thickness (µm), adhesion strength (DIN EN ISO 4624), porosity, roughness and corrosion resistance (DIN EN ISO 9227) are evaluated. Defective coating systems lead to filiform/under-film corrosion or delamination.

Decision-making perspectives:

• Technical decision-makers: selection of suitable coating systems depending on medium, temperature and tribological load.
• Purchasing/project management: specification of layer thicknesses, standard tests and acceptance criteria.
• Science: analysis of interfaces, diffusion zones and layer-growth mechanisms.
• Insurance/law: proof of standard-compliant execution and documentation in the event of corrosion damage.

Typical testing or verification methods: layer thickness measurement, cross-cut test, pull-off adhesion test, salt spray test, SEM/EDX analysis.

FAQ:

• How is the quality of a coating tested?
• By measuring layer thickness, adhesion strength and porosity, as well as through standardised corrosion and wear tests.

Definition: Component metallography is the metallographic examination of the microstructure directly on the component or on representatively extracted samples. It serves to assess heat-treatment conditions, weld seam qualities and damage-relevant microstructural changes. It is based on preparative sectioning techniques as well as light or electron microscopy analyses.

Practical relevance: Grain size (DIN EN ISO 643), phase distribution, precipitates, crack formation or decarburisation depths are evaluated. The method is central to failure analysis, in cases of suspected HTHA (High Temperature Hydrogen Attack) or for verifying material specifications. Replica techniques enable in-situ examinations without full disassembly.

Decision-making perspectives:

• Technical decision-makers: assessment of microstructural inhomogeneities, weld seam zones and remaining service life.
• Purchasing/project management: verification of specification-compliant heat treatment and manufacturing quality.
• Science: microstructure analysis, correlation of microstructure and mechanical properties.
• Insurance/law: documentation of the material condition to secure evidence in the event of damage.

Typical testing or verification methods: sample preparation, light microscopy, scanning electron microscopy (SEM), hardness testing, microstructure etching.

FAQ:

• Is component metallography possible non-destructively?
• Replica methods are minimally invasive; classic sectioning examinations require material extraction.

Definition: The compression test is a mechanical testing method for determining the behaviour of a material under axial compressive loading. A cylindrical or prismatic specimen is loaded between two compression platens up to a defined load or until failure. The method is standardised, among others, in DIN EN ISO 6892-1 (for metals, complementing the tensile test).

Practical relevance: The properties determined are compressive strength, modulus of elasticity and plastic compression behaviour. The compression test is particularly relevant for brittle materials such as cast iron, ceramics or concrete, where the compressive strength is considerably higher than the tensile strength. Influencing factors are specimen geometry, friction at the compression platens and testing speed.

Decision-making perspectives:

• Technical decision-makers: Design of compression-loaded components and assessment of failure mechanisms.
• Purchasing/project management: Specification of required minimum compressive strengths in material specifications.
• Science: Analysis of non-linear deformation mechanisms and material models.
• Insurance/law: Documented verification of mechanical properties in cases of structural failure.

Typical testing or verification methods: Universal testing machine with compression platens, strain measurement, evaluation of stress-strain curves.

FAQ:

• When is a compression test more appropriate than a tensile test?
• For brittle materials or components that are predominantly subjected to compression, the compression test provides more realistic characteristic values.

Definition: Contour measurement is a metrological method for capturing and evaluating profile shapes and geometry elements of a workpiece. In the process, actual contours are compared with nominal data. The aim is to assess form deviations, radii, angles or transitions.

Practical relevance: Contour measurements are particularly relevant for sealing faces, grooves, gear teeth or free-form surfaces. Tactile stylus instruments or optical measuring systems are used. The basis for evaluation is technical drawings or CAD models as well as GPS standards. Influencing factors are the stylus force, filter settings and measurement uncertainty.

Decision-making perspectives:

• Technical decision-makers: Ensuring function-relevant profile geometries and transition radii.
• Purchasing/project management: Defining clear contour and profile requirements in specifications.
• Science: Analysis of profile deviations and signal processing (filters according to ISO 16610).
• Insurance/law: Demonstrating geometric deviations in the case of functional or leak-tightness problems.

Typical testing or verification methods: Stylus profiling method, optical profilometry, CAD comparison measurement, evaluation with form and profile tolerances.

FAQ:

• How does contour measurement differ from roughness measurement?
• Contour measurement evaluates macrogeometric profile shapes, whereas roughness measurement analyses microscopic surface structures.

Definition: Corrosion engineering covers the holistic planning, assessment and optimisation of corrosion-relevant aspects in technical installations and products. It integrates material selection, protection concepts, operating parameters and inspection strategies. The aim is to sustainably ensure integrity and cost-effectiveness.

Practical relevance: The basis is knowledge of corrosion mechanisms, media conditions, temperature and pressure ranges as well as normative requirements (e.g. DIN EN ISO 8044, API 571). Measures include suitable material selection, coating systems, cathodic protection, water chemistry control and Risk-Based Inspection (RBI). A lack of systematic planning leads to increased maintenance costs and failure risks.

Decision-making perspectives:

• Technical decision-makers: Development of integrative corrosion protection strategies across the entire life cycle.
• Purchasing/project management: Definition of clear material and protection requirements in specifications.
• Science: Modelling of corrosion rates and assessment of new protection technologies.
• Insurance/law: Demonstration of systematic risk assessment and compliance with technical codes and standards.

Typical testing or verification methods: Corrosion testing, electrochemical analyses, wall thickness measurement (UT), RBI analyses, materials analytics.

FAQ:

• What distinguishes corrosion engineering from individual tests?
• It considers corrosion risks holistically and with a life-cycle orientation rather than as isolated individual tests.

Definition: Corrosion mechanisms describe the physico-chemical processes that lead to the degradation of a material through reaction with its environment. They are usually based on electrochemical redox reactions between metal, electrolyte and oxidising agent. The type and progression depend on the material, medium, temperature and mechanical loading.

Practical relevance: The most important mechanisms include uniform surface corrosion, pitting corrosion, crevice corrosion, galvanic corrosion, stress corrosion cracking (SCC) and hydrogen-induced cracking. Evaluation parameters are the corrosion rate (mm/year), potential differences, pH value and chloride content. Normative definitions can be found, among others, in DIN EN ISO 8044. Knowledge of the mechanism is a prerequisite for effective corrosion protection.

Decision-making perspectives:

• Technical decision-makers: Selection of suitable materials, coatings or protection systems.
• Purchasing/project management: Specification of corrosion-resistant materials and testing requirements.
• Science: Analysis of electrochemical processes and material-medium interactions.
• Insurance/law: Determining the cause of corrosion damage and assessing the duty of care.

Typical testing or verification methods: Electrochemical measurements, salt spray test, metallography, wall thickness measurement (UT).

FAQ:

• Why is identifying the corrosion mechanism important?
• Only by knowing the mechanism can suitable protection and prevention measures be defined.

Definition: Corrosion protection encompasses all technical measures to prevent or slow down corrosion of materials. It can be achieved through design, materials engineering, electrochemical means or coating systems. The aim is to extend service life and ensure operational safety.

Practical relevance: Measures include suitable material selection, coating systems in accordance with DIN EN ISO 12944, cathodic corrosion protection or adjustment of the water chemistry. Protection duration, coating thickness, adhesion strength and inspection intervals are assessed. The effectiveness depends strongly on environmental conditions such as humidity, chloride content and temperature.

Decision-making perspectives:

• Technical decision-makers: Selection of economically and technically suitable protection concepts.
• Purchasing/project management: Specification of protection classes, coating systems and testing requirements.
• Science: Investigation of passivation, diffusion processes and protection mechanisms.
• Insurance/law: Demonstration of appropriate protective measures in the event of corrosion damage.

Typical testing or verification methods: Salt spray test, coating thickness measurement, pull-off adhesion test, potential measurement in cathodic protection.

FAQ:

• Which standard governs coating systems in corrosion protection?
• DIN EN ISO 12944 describes the corrosion protection of steel structures by means of coating systems.

Definition: Corrosion testing is the experimental investigation of the resistance of a material or coating system to corrosive media. The aim is the quantitative or qualitative assessment of corrosion behaviour under defined conditions. Test methods are governed by standards, for example in DIN EN ISO 9227.

Practical relevance: Corrosion tests include salt spray tests, climatic tests, immersion tests or electrochemical measurements. The corrosion rate, mass loss, pitting corrosion or undercutting of coatings are assessed. The results serve material selection, qualification of coatings and service life estimation.

Decision-making perspectives:

• Technical decision-makers: Selection of suitable material or coating systems for defined media.
• Purchasing/project management: Definition of binding test requirements and acceptance criteria.
• Science: Investigation of corrosion kinetics and comparison of accelerated test methods with field exposure.
• Insurance/law: Demonstration of resistance or root cause determination in the event of corrosion damage.

Typical testing or verification methods: Salt spray test (DIN EN ISO 9227), condensation cyclic climate, electrochemical polarisation measurement, long-term exposure.

FAQ:

• Does the salt spray test replace real operating conditions?
• No, it is an accelerated comparative method and reflects real operating conditions only to a limited extent.