1, the hardness of the heat treatment of the workpiece using a hardness tester. PHR series portable surface Rockwell hardness testers are suitable for testing the hardness of surface heat-treated workpieces, and can test various surface heat-treated workpieces with effective depth of more than 0.1mm. Easy to operate, easy to use, and low in price, the hardness value can be read directly.

2, surface heat treatment is divided into two categories, one is the surface quenched and tempered heat treatment, the other is chemical heat treatment, the hardness test method is as follows: chemical heat treatment is the workpiece surface infiltration of one or several chemical elements of atoms, Change the chemical composition, texture and properties of the workpiece surface. After quenching and tempering at low temperature, the surface of the workpiece has high hardness, wear resistance and contact fatigue strength, while the core of the workpiece has high toughness.

3, chemical heat treatment The main technical parameters of the workpiece is the depth of the hardened layer and the surface hardness. Depth of hardened layer is still measured by Vickers hardness tester. The distance from the surface of the workpiece to the point where the hardness drops to 50HRC is detected. This is the effective hardening depth of the chemical heat treatment of the workpiece surface hardness testing and surface hardening heat treatment workpiece hardness testing is similar, can use Vickers hardness tester, surface Rockwell hardness tester or Rockwell hardness tester to detect, but the thickness of nitriding thicker Thin, generally not more than 0.7mm, then Rockwell hardness tester can no longer be used. If the local hardness of the part is required to be higher, the partial quenching heat treatment may be performed by means of induction heating. Such parts usually have the location of the local quenching heat treatment and the local hardness value on the drawing. Hardness testing of parts is performed within the specified area. The hardness tester can use Rockwell hardness tester to test the HRC hardness value. If the hardened heat treatment layer is shallow, a Rockwell hardness tester can be used to test the HRN hardness value.

4. Surface quenching and tempering Heat treatment is usually performed by induction heating or flame heating. The main technical parameters are surface hardness, local hardness and effective hardened layer depth. Vickers hardness tester can be used for hardness test. Rockwell or Rockwell hardness tester can also be used. The choice of test force (scale) is related to the effective hardened layer depth and the surface hardness of the workpiece. There are three hardness scales involved here. Vickers hardness tester is an important means to test the surface hardness of the heat treatment workpiece, it can use 0.5 ~ 100kg of test force, test thin to 0.05mm thick surface hardened layer, its accuracy is the highest, can distinguish the tiny surface hardness of the workpiece difference. In addition, the effective hardened layer depth is also detected by the Vickers hardness tester. Therefore, it is necessary to provide a Vickers hardness tester for the unit that performs the surface heat treatment process or uses a large number of surface heat-treated workpieces.

5. The Rockwell hardness tester is also suitable for testing the hardness of hardened parts. The Rockwell hardness tester has three scales to choose from. It is possible to test various hardened workpieces with an effective hardening depth of more than 0.1 mm. Although the accuracy of the surface Rockwell hardness tester is not as high as that of the Vickers hardness tester, it has been able to meet the requirements as a means of quality control and inspection of the heat treatment plant. Moreover, it also has the features of simple operation, convenient use, low price, rapid measurement, direct reading of hardness value, etc. The use of surface Rockwell hardness tester can quickly and non-destructively detect each batch of surface heat-treated workpieces. This is important for metal processing and machinery manufacturing plants. Rockwell hardness tester can also be used when the surface heat treatment hardened layer is thick. When the thickness of hardened layer is 0.4-0.8mm, HRA scale can be used. When the thickness of hardened layer exceeds 0.8mm, HRC scale can be used.

6. Vickers, Rockwell, and Surface Rockwell hardness values can be easily converted to each other and converted to standard, drawing, or user hardness values. Corresponding conversion tables are given in the International Standard ISO, American Standard ASTM and Chinese Standard GB/T.