Hardware shrapnel various heat treatment classification and hardness requirements
1. The hardness of the heat treated workpiece is measured by hardness tester. PHR series portable surface Rockwell hardness tester is suitable for testing the hardness of surface heat treatment workpiece, and can test various surface heat treatment workpieces with effective depth of more than 0.1mm. Simple operation, easy to use and low price, it can directly read hardness value.
2, surface heat treatment is divided into two categories, one is the surface quenching and tempering treatment, the other is the chemical heat treatment, the hardness test method: chemical heat treatment is to make the surface of the workpiece into one or several chemical elements atoms, thus changing the chemical composition, microstructure and mechanical properties of the workpiece surface. After quenching and low temperature tempering, the surface of the workpiece has high hardness, wear resistance and contact fatigue strength, and the core of the workpiece has high strength and toughness.
3. The main technical parameters of the chemical heat treatment workpiece are the depth of hardening layer and the surface hardness. The depth of the hardened layer shall be measured by Vivtorinox hardness tester. Detect the distance from the surface of the workpiece to the point where the hardness drops to 50HRC. This is the hardness of surface hardness and effective hardening depth of chemical heat treatment of workpiece detection and surface quenching workpiece detection can be similar to that of the surface Rockwell hardness and Rockwell hardness tester to test Vivtorinox hardness and nitriding, only thick thin, generally not more than 0.7mm, then you can not use the Rockwell the hardness of the. If parts of the parts require higher hardness, induction heating can be used to carry out local hardening treatment, such parts are usually marked on the drawings, local quenching treatment location and local hardness value. The hardness test of the parts shall be carried out in the designated area. Hardness tester can use Rockwell hardness tester, test HRC hardness value, such as heat treatment hardening layer is shallow, can use surface Rockwell hardness tester, test HRN hardness value.
4. Surface quenching and tempering are usually performed by induction heating or flame heating. The main technical parameters are surface hardness, local hardness and effective depth of hardened layer. Hardness test can be made by Vivtorinox hardness tester, Rockwell or surface Rockwell hardness tester. The choice of test force (gauge) is related to effective depth of hardened layer and hardness of workpiece surface. Three kinds of hardness testers are involved here. Vivtorinox hardness test is an important means of heat treatment of workpiece surface hardness, it can choose 0.5 ~ 100kg test, to test thin surface hardened 0.05mm thick layer, its precision is the highest, and it can distinguish the tiny difference of workpiece surface hardness. In addition, effective hardening layer depth to the Vivtorinox hardness to detect, therefore, for the surface heat processing unit or the heavy use of heat treatment on the surface of the workpiece, equipped with a Vivtorinox hardness is necessary.
5, the surface Rockwell hardness tester is also very suitable for testing surface hardening workpiece hardness, surface Rockwell hardness tester has three kinds of rulers can choose. A variety of surface hardened workpieces with an effective hardening depth of over 0.1mm can be tested. Although the accuracy of the Rockwell hardness tester is not as high as that of the Vivtorinox hardness tester, it has been able to meet the requirements of the quality control and qualification inspection of the heat treatment plant. Besides, it also has the advantages of simple operation, convenient use and low price, the characteristics of rapid measurement, can be directly read the hardness, the surface Rockwell hardness of surface thermal batch workpiece fast nondestructive detection by piece. This is important for Metalworking and machinery manufacturing plants. When the surface heat treatment hardening layer is thicker, Rockwell hardness tester can also be used. When the thickness of the hardening layer is between 0.4 and 0.8mm, the HRA scale can be adopted. When the thickness of the hardened layer is more than 0.8mm, the HRC scale can be adopted.
6, Vivtorinox, Rockwell and surface Rockwell three hardness values can be easily converted to each other, converted to standards, drawings or user hardness requirements. The corresponding conversion tables have been given in international standard ISO, American Standard ASTM and Chinese standard GB/T.
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