Tensile strength is probably the most commonly used measure of a material's strength. Tensile test requirements are almost always included in metal alloy specification requirements. The tensile test usually provides the ultimate tensile strength, tensile yield strength, elongation, and for some alloys, the reduction of area. The ultimate tensile strength is the breaking strength in tension. The yield load is the load at which the material becomes permanently deformed and the elongation is the increase in length. Tensile test results are often used to estimate other mechanical properties and to evaluate the fabricating characteristics of a material .
We perform tensile tests on cast and wrought metal alloys, welds, and some plastic materials. We are equipped to machine standard size or sub-size tensile specimens from bars, shapes, sheets, tubes, forgings, and castings. The dimensions for standard ASTM test specimens are shown below.
Compression, Flexural, Shear, & Bend Tests
Compression and flexural tests are quite valuable for "sandwich" construction, plastics and various composite materials. Flexure is sometimes measured on transverse tests of gray iron. Shear tests are common on small rivets and bolts. The value of the bend test is repeatedly overlooked. Bend tests should be used as a routine receiving inspection test for metals that are to be formed. It is a simple test that usually can be performed without special equipment. Bend tests are part of most routine weld tests.
Hardness Tests; Brinell - Rockwell - Knoop - Diamond Pyramid (Vickers)
Hardness is closely related to strength in metals and is often included in specification requirements as a measure of strength. Brinell and Rockwell hardness tests are especially valuable because of their non-destructive nature. Brinell and Rockwell hardness tests require a part or specimen with smooth parallel sides and can also be made on some cylindrical parts. Brinell hardness tests generally require a thickness of at least 0.375 inc. Knoop and Diamond Pyramid microhardness tests are used for case depth, decarburization, and plating hardness measurements and are made on polished sections cut from parts or test specimens. The hardness of parts too small for Rockwell hardness test can usually be measured by microhardness test. We can cut sections for microhardness tests from almost anything.
Impact Tests; Charpy - Izod - Tensile Impact
Impact tests are used as a measure of the toughness of a material, particularly at low temperatures. We can make tests at temperatures to -90 degrees. The standard impact specimen is ten mm square by two inches long. Sub-size specimens can also be made. Most specifications call for an average of three or more specimens.
Other Mechanical Tests
We can also perform the following mechanical tests on many parts or assemblies.
|Proof load or proof stress tests on chains, cables, parts, and assemblies|
|Spring rate and other load tests on springs|
|Torque tests on self-locking bolts and nuts|
|Proof pressure and leak tests|