Technical analysis for testing the hardness of forging parts

In order to eliminate the processing stress, adjust the structure, refine the grain, and create good conditions for the subsequent processing, the forging parts should be subjected to appropriate heat treatment after processing. Heat treatment methods include annealing, normalizing, normalizing tempering, quenching tempering, etc. In order to ensure the efficiency of heat treatment, most of the hardness values of the workpiece are specified within a certain range of hardness, and a few are specified below a certain hardness value. Most hardness testing methods specify the use of Brinell durometers, a few use Rockwell durometers, and some medium to large workpieces can use either a Shower or a Rieger durometer.



As we all know, Brinell hardness tester is mainly used for hardness inspection of forgings, Brinell hardness values are mostly required on the standard or user drawings. All kinds of forgings require inspection piece by piece, and each workpiece also requires multi-point inspection.



For small forging parts, it can be tested directly on the bench Brinell hardness tester. Medium and large forgings cannot be tested on a desktop computer. There are two types of hardness test methods. One is to use a portable Brinell hardness tester, the other is to use other portable hardness tester, measure and convert it to a Brinell hardness value.



Forgings are usually mere blanks of mechanical parts. After forging production, it must be sent to the processing plant for processing, and after processing, it must be heat treated. Heat treatment methods include normalizing, quenching and tempering, carburizing, nitriding, local high frequency quenching, etc. Some of the heat treated workpieces can be directly used as mechanical parts, and some have to go through grinding and other terminal processing, and then used as mechanical parts.



Compared with the mechanical parts processed by other methods (such as extrusion, rolling, casting, etc.), the mechanical parts processed by the blank of mechanical forging have better final mechanical properties. These workpieces should have good toughness and reach the specified hardness. They shall have the strength, wearability, surface hardness or local hardness that the workpiece should have under the conditions of use.



Therefore, the workpiece after heat treatment should be subjected to precision hardness test, the use of hardness tester should be Rockwell hardness tester. Benchtop Rockwell hardness tester can be used when the workpiece is small. A portable Rockwell hardness tester should be used when the workpiece is large, heavy or long. When portable Rockwell durometers are not available or the hardness test accuracy is not high, the forgings may use a Shohl, Riehl or hammer Brinell durometer.