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About welding requirements of 12Cr1MoV steel

12Cr1MoV steel has good welding performance and is sensitive to the cooling rate of normalizing. When the cooling is faster, the durable strength is higher. 12Cr1MoV steel has temper brittleness when tempered at 500-700 ° C. It will cause carbide spheroidization when 12Cr1MoV steel is operated at 570°C for a long time, and it is generally used after normalizing and high temperature tempering. But it should be noted that 12Cr1MoV steel should be preheated before welding, heat treatment after welding to relieve stress, and follow the following general requirements during welding:

1. Thoroughly clean the groove before welding of 12Cr1MoV steel to avoid sticking of rust, oil, paint, sand and mud.
2. Avoid striking the arc on the base metal during welding. Where the arc is struck, it should be smoothed and then color-checked to eliminate defects;
3. Spot welding is done by qualified welders, and the welding consumables and welding process of 12Cr1MoV steel used are the same as the formal welds;
4. When there is a valve, it should be opened after the valve is opened;
5. After the welding is completed, the steel number of the welder for 12Cr1MoV steel should be marked and marked on the one-line diagram
6. The purity of the protective gas should be above 99.96%.