Mechanical Testing
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Mechanical testing is necessary to provide important information about the aptness and characteristics of a material for its intended usage.
This helps companies design dependable products that will consistently perform in a predictable manner. The LAB—Materials Testing is an accredited mechanical testing lab that provides accurate, reliable mechanical testing of metals.
Materials undergoing mechanical testing are measured under various tension, compression, and load conditions to determine strength, ductility, impact resistance, elongation, stress, toughness, and hardness.
The LAB conducts the following types of mechanical testing:
Physical Properties
Hardness Testing
Fastener Testing
All mechanical tests at The LAB are performed per ASTM, SAE, MIL, ISO, or other standards. The LAB's experienced technicians and comprehensive quality control program ensure complete, reproducible, and accurate results every time. The LAB’s clients have come to expect exceptional customer service, quick turnaround, and competitive pricing for their mechanical testing requirements.
Definitions/Supplementary Information on Mechanical Testing Types
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Physical Properties: Magnetic Permeability
A magnetic permeability test measures a material’s ability to become magnetized. When a material is placed in a magnetic field, it interacts with the field in one way or another. If a material is more conducive to being magnetized, it will have a higher permeability.
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Hardness Testing: Rockwell, Superficial Rockwell, and Microhardness
To best determine a material’s strength, ease of machinability, and wear resistance, a technician would conduct a resistance-to-penetration hardness test. Rockwell hardness testing is a commonly used method for determining the superficial hardness of a material. It is also valuable in helping to make decisions about treatments and coatings. Hardness tests are performed on castings, forgings, fasteners, and other metal products and samples.
Superficial Rockwell testing is similar; the difference is that technicians use smaller minor and major load values.
Microhardness tests a material’s hardness in a similar way to Rockwell, but with a microscopic indentation. This test can provide a hardness value for a very precise location on a part, enabling the detection of variations in hardness from one location to another. All tests offer different load options and many different scales between the three testing options.
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Impact Testing: Charpy V-Notch Impact
Charpy Impact Testing is a routine method of testing to determine a material's toughness, brittleness, and ductility. Materials at The LAB are tested to varying temperature requirements and specifications.
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Tensile Testing: Machined Specimens
The LAB—Materials Testing performs tensile testing in accordance with industry standards. Tensile testing is one of the most essential types of material strength testing. It is a destructive test process that applies an ever-increasing load to a specimen, past the yield and up to the point of failure. The test provides fundamental information on a specimen’s mechanical properties such as tensile strength, deformation, reduction of area, yield strength, strain hardening behavior, and elongation or ductility of a material.
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Fastener Testing
The LAB—Materials Testing performs various types of fastener testing to determine the mechanical properties of externally- and internally-threaded fasteners. The types of fastener testing commonly performed at The LAB are yield strength, axial and wedge tensile, proof load, hardness testing, and magnetic permeability. Since many of the tests have already been described above, the focus in this section will be on axial and wedge tensile testing and proof load.
Axial and wedge tensile testing is done to determine the behavior of materials under axial tensile loading. Axial tests are performed by securing the fastener into the testing machine and then applying force to the fastener by separating the testing apparatus crossheads. The wedge test is also an axial test. The difference is that a wedge is placed under the head during testing to see if the head of the fastener can withstand the added stress of the wedge. The wedge tensile test is usually done on square or hex head fastener and socket head cap screws.
Finally, a proof load test entails stressing the material specimen with a quantified load that the specimen must withstand without measurable permanent set. The load used to stress the fastener is specific to the size and grade/property class of the specimen.