Mid-West Materials Metallurgical
Testing Laboratory

Every grade of steel is expected to conform to a specific range of metallurgical characteristics. Since variations from expected performance can cause serious problems, all materials purchased are subject to a series of routine physical checks to assure all material received is properly identified.

A Rockwell hardness test is performed on all steel. The results of this test, taken together with the mill information provided and the customer's requirements, determine additional testing.

The Rockwell hardness test measures the degree of penetration of 1/16" tungsten-carbide ball into the material when it is subjected to a 100 kilogram load. The penetration is expressed as a number from 1 to 100 on the so-called "B" scale. A higher Rockwell number indicates a higher surface hardness. When materials are harder than can be expressed on the "B" scale, a diamond penetrator is used under a 150 kg. load, and the results are reported on the "C" scale.