The material testing includes various test procedures to which the behavior and characteristics of the material of normalized samples of material ( Material Analysis ) or finished components ( component testing ) are calculated using mechanical, thermal or chemical stresses.
A material is checked for its purity, freedom from defects or resilience. According to the type, the common test methods are divided into two main areas: destructive and non-destructive material testing. The tests aimed at estimating the service life of products and materials fall into the field of environmental simulation .
The gun test shown in the picture shows a very early and pragmatic form of material testing: The material is tested on the finished product. The gun barrel to be tested was slipped over a ball lying on a pole - once the barrel survived the ignition of the powder charge, it could continue to be used. In this test, a mass had to be accelerated that was significantly larger than the ball to be accelerated later.
Destructive material testing
In destructive material testing , selected materials are tested for chemical and physical properties and for this purpose destroyed or (superficially) changed; the component to be tested can then no longer be used. The main methods of this type of examination are:
- Weld-on bending test
- Pull-out attempt
- Bending test and folding test of metal sheets
- Blue fracture test to test steels for macroscopic, non-metallic inclusions
- Bulge test
- Fatigue test according to Wöhler
- Print attempt
- Charpy impact test according to Charpy , Izod and tensile impact
- Shear test
- Cupping test according to Erichsen
- Torsion test
- Creep test
- Tensile test to test the tensile strength , especially the elastic limit
- Chemically and thermally:
Conditionally non-destructive material testing
In order for a component to be conditionally non-destructive testing, it must have a certain minimum size and surfaces provided for it. If the inside of a component is to be tested, the area to be tested must first be milled out, which can only result in destruction of the component.
nondestructive material test
In non-destructive material testing , or NDI for short (EN 1330, non-destructive testing / non-destructive inspection , NDT or NDI for short), the quality of a workpiece is tested without damaging the material itself. For this purpose, various physical effects are used, which are divided into two groups: Defectoscopy and Qualimetry . The dynamic test methods are based on the reflection of elastic or electromagnetic waves at an interface, which are defined by the acoustic or dielectric impedance contrast.
Among the first non-destructive material tests were the determination of the density by the displacement method according to Archimedes and the visual inspection, i. H. viewing a component for externally recognizable defects. Most often, however, this is understood to mean tests for component defects.
The non-destructive testing methods can be sorted according to different aspects. The following table gives an overview of the most common processes in mechanical engineering, aerospace engineering and construction. The common abbreviations or the abbreviations according to ISO 9712 and EN 4179 are given. The dynamics indicate the character of the measurement, whereby “static” i. d. Usually the measurement of a static electric or magnetic field means, "dynamic" means the measurement of a wave amplitude. The principle is to be understood as the physical measuring principle (mechanical, electrical, magnetic, thermal, optical, chemical). The interaction space with the object of investigation and the general normative basis are given in the corresponding columns.
|Acoustic resonance analysis||ART||dynamic||mechanically||volume||DGZfP guideline US06|
|Reinforcement location (inductive)||static||magnetic||volume||DGZfP leaflet B02|
|Reinforcement location (capacitive)||static||electric||volume||DGZfP leaflet B02|
|Ground radar||GPR||dynamic||electromagnetic||volume||DGZfP leaflet B10|
|Strain gauge test||ST||dynamic||mechanically||surface|
|Radiographic examination||RT||dynamic||electromagnetic||volume||EN 444, EN 13068, EN 16016|
|Humidity measurement (capacitive)||static||electric||surface||EN 13183-3|
|Moisture measurement (resistive)||static||electric||surface||EN 13183-2|
|Impact echo method||IE||dynamic||mechanically||volume||DGZfP leaflet B11|
|Potential field measurement||static||electrochemical||volume||DGZfP leaflet B03|
|Rebound hammer||dynamic||mechanically||surface||EN 12504-2|
|Leak test||LT||chemically||system||EN 1779, EN 13184, EN 13185, EN 1593|
|Penetrant testing||PT||mechanically||surface||EN 571-1|
|Time domain reflectometry||TDR||dynamic||electromagnetic||volume||DIN 19745|
|Infrared thermography||TT||dynamic||thermal||surface||DIN 54190, DIN 54192, EN 13187|
|Conductivity test||electrical, thermal||volume||material-dependent|
|magnetic inductive method||static||magnetic||surface||ISO 2178|
|Magnetic particle inspection||MT||static||magnetic||surface||ISO 9934|
|X-ray fluorescence analysis||static||electromagnetic||surface|
|Acoustic emission analysis||AT||dynamic||mechanically||volume||EN 13554|
|Visual inspection||VT||optically||surface||EN 13018, DGZfP data sheet B06|
|Stray field measurement||FT||static||magnetic||volume||EN 10256|
|Ultrasonic testing||UT||dynamic||mechanically||volume||EN 583, DGZfP data sheet B04|
|Vibration test / vibration analysis||VA||dynamic||mechanically||system||ISO 13373, DIN 45669|
|Eddy current testing||ET||static||electric||surface||ISO 15549|
Further known methods can be classified as subgroups of the methods mentioned above.
|Radiographic examination||Computed tomography , x-ray radiation, gamma radiation|
|Visual inspection||Endoscopy , microscopy , metallography|
Material tests are carried out by different facilities. In Germany, this includes the Federal Institute for Materials Research and Testing and the individual material testing institutes at the state level . In addition, various testing organizations and scientific institutes, such as the Fraunhofer Institute for Non-Destructive Testing or the Austrian Research Center for Non Destructive Testing , offer material testing as a service. In addition, there are medium-sized private-sector testing organizations. The internationally accredited companies in Germany are organized in the specialist association of accredited auditing companies, F-GZP for short.
- Gernot Krankenhagen / Horst Laube: Material testing, of explosions, fractures and tests. rororo, 1983, ISBN 3-499-17710-2 .
- Frank Schmidt-Döhl : Material testing in construction. Fraunhofer irb-Verlag, Stuttgart 2013, ISBN 978-3-8167-8747-1 .
- Karl Heinz Beelich, Olaf Jacobs: Examination trainer materials science , CD-ROM. Vogel Buchverlag, Würzburg 2012, ISBN 978-3-83433274-5 .
- NDT.net Portal and Open Access Archive of Nondestructive Testing
- cen.eu: European Committee for Standardization, Technical Committee 138: Non-Destructive Testing
- dgzfp.de: German Society for Non-Destructive Testing e. V.
- oegfzp.at: Austrian Society for Non-Destructive Testing
- ifam.fraunhofer.de: Materials testing at Fraunhofer IFAM
- mpanrw.eu: Materials testing in the Materials Testing Office in North Rhine-Westphalia
- nmp.din.de: Material Testing Standards Committee
- Blumenauer, materials testing, 6th edition, p. 306
- ISO 9712: 2012. Non-Destructive Testing - Qualification and certification of non-destructive testing personnel .
- EN 4179: 2009. Aerospace - Qualification and approval of personnel for non-destructive testing .
- EN 444: 1994. Non-destructive testing - radiographic methods - computed tomography
- EN 13068-1: 1999. Non-Destructive Testing - Radioscopic Testing .
- EN 16016-1: 2011. Non-destructive testing; Basics for radiographic testing of metallic materials with X-rays and gamma rays
- EN 13183-3: 2005. Moisture content of a piece of sawn timber - Part 3: Estimation by capacitive measuring method .
- EN 13183-2: 2002. Moisture content of a piece of sawn timber - Part 2: Estimation by electrical resistance measurement method .
- EN 12504-2: 2001. Testing of concrete in buildings - Part 2: Non-destructive testing; Determination of the rebound number .
- EN 1779: 1999. Non-destructive testing - leak testing - criteria for the selection of test methods and procedures .
- EN 13184: 2001. Non-destructive testing - leak testing - pressure change method .
- EN 13185: 2001. Non-destructive testing - leak testing - tracer gas method .
- EN 1593: 1999. Non-destructive testing - leak testing - bubble testing method .
- EN 571-1: 1997. Non-destructive testing - Liquid penetrant testing - Part 1: General principles .
- DIN 19745: 2006. Soil quality - Basics for the determination of the water content by time domain reflectometry (TDR) and time domain transmissometry (TDT) .
- DIN 54190. Non- destructive testing - thermographic testing .
- DIN 54192: 2012. Non-Destructive Testing - Active Thermography .
- EN 13187: 1998. Thermal behavior of buildings - detection of thermal bridges in building envelopes - infrared method .
- ISO 2178: 1995. Non-magnetic coatings on magnetic base metals - measuring the layer thickness - magnetic method .
- ISO 9934. Non- destructive testing - magnetic particle testing .
- EN 13554: 2011. Non-destructive testing - Acoustic emission testing - General principles .
- EN 13018: 2001. Non-destructive testing - visual testing - general principles .
- EN 10256: 2000. Non-destructive testing of steel pipes - qualification and competence of level 1 and 2 personnel for non-destructive testing .
- EN 583. Non-destructive testing - ultrasonic testing .
- EN 13373. Condition monitoring and diagnostics of machines - vibration condition monitoring .
- DIN 45669. Measurement of vibration immissions .
- ISO 15549: 2008. Non-Destructive Testing - Eddy Current Testing - General Basics .