How is the Quenching Treatment of ERW Steel Pipe Carried Out?
Date:2022-04-07View:571Tags:ERW Steel Pipe,Quenching Treatment
The surface quenching and tempering heat treatment of erw steel pipe is usually carried out 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 testing, Rockwell or surface Rockwell hardness tester can also be used. The selection of the test force (scale) is related to the depth of the effective hardened layer and the surface hardness of the erw steel pipe.
Vickers hardness tester is an important means to test the surface hardness of heat-treated erw steel pipes. It can use a test force of 0.5-100kg to test the surface hardened layer as thin as 0.05mm thick. It has the highest accuracy and can distinguish the surface hardness of heat-treated workpieces. small differences. In addition, the depth of the effective hardened layer is also detected by a Vickers hardness tester. Therefore, it is necessary to have a Vickers hardness tester for units that perform surface heat treatment or use a large number of surface heat treated erw steel pipes.
The surface Rockwell hardness tester is also very suitable for testing the hardness of surface quenched workpieces. There are three scales for the surface Rockwell hardness tester to choose from. Various case hardened erw steel pipes with an effective hardening depth exceeding 0.1mm can be tested. 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 detection method for quality management and qualification inspection of heat treatment plants. Moreover, it also has the characteristics of simple operation, convenient use, low price, rapid measurement, and direct reading of hardness values. Using the surface Rockwell hardness tester, batches of surface heat-treated erw steel pipes can be quickly and non-destructively tested piece by piece.
When the surface heat treatment hardened layer is thick, the Rockwell hardness tester can also be used. When the thickness of the heat treatment hardened layer is 0.4-0.8mm, the HRA scale can be used, and when the thickness of the hardened layer exceeds 0.8mm, the HRC scale can be used.
The three hardness values of Vickers, Rockwell and superficial Rockwell can be easily converted to each other and converted into standard, drawing or user-required hardness value. The corresponding conversion table has been given in the international standard ISO, American standard ASTM and Chinese standard GB/T.
If the local hardness of the parts is high, the local quenching heat treatment can be carried out by means of induction heating. For such erw steel pipes, the location and local hardness value of the local quenching heat treatment are usually marked on the drawings. The hardness test of erw steel pipe should be carried out in the designated area. The hardness testing instrument can use the Rockwell hardness tester to test the HRC hardness value. If the heat treatment hardening layer is shallow, the surface Rockwell hardness tester can be used to test the HRN hardness value.
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