A tensile test is a basic testing method to measure the yield point, the tensile strength and the elongation of a steel sheet. In case of a usual tensile test, some load is increased until the test piece is broken while some load is added to a fixed test piece.
The kind and sizes, etc. of test pieces are specified in all of the specifications, such as KS, JIS and ASTM, etc. in order for you to prepare for test a tensile test. In case of a cold-rolled steel sheet, a way of selecting a test piece, which is specified in KS B 0801 No.5, is generally used.
Results from a Tensile Test
The results from a tensile test are used as the most basic standards to judge the workability and formability.
Rockwell Hardness Test
In this test, a hard steel ball is forced into surface of the test specimen, first under a fixed minor load and than under a major load. On remove the major load, the permanent depth of impression is measure, and a number derived form the net increase in the depth of impression in the two operations is read directly on the Rockwell hardness B- scale and Rockwell superficial hardness 30T-scale. The B-scale is based on a steel ball 1/16 in. [1.558 mm] in diameter and a 100kg test-load. The 30T-scale consists of a 30kg test load and a steel ball of the same diameter. The B-scale is highly dependable when the test specimen is 0.762mm [0.030in] or thicker. For thicknesses less than 0.762mm, therefore, use of the 30T-scale is recommended.