Of the three heat treatment temperatures, which one is reliable?
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The minimum temperature for heat treatment of 12Cr1MoVG is 650 degrees according to NB/T47015-2011, 680 degrees per GB/T16507-2013, and the temperature range is 720–750 degrees according to DL/T869-2021. Good heavens, which standard can be trusted? Should we decide by drawing lots?
If it is a boiler or pressure vessel, use the temperature specified in NB/T47015
If no specifications are given in the drawings, it is recommended to use the temperature range of 720–750°C as specified in DL/T869-2021. There are many boilers for electricity generation; this material is widely used in boilers, and there’s plenty of experience with it. There is also more relative verification.
The heat treatment depends on your goal: whether it is annealing or normalizing, quenching or tempering. Annealing is below the phase transition temperature, while normalizing is above it. It’s usually around 50 degrees. Find the phase transition temperatures of various materials by yourself, and decide which range to use. This is the basis for determining the temperature in heat treatment.
For example, carbon steel plate manufacturers generally use normalizing. When manufacturers weld with this material, they perform more annealing to relieve stress.
A WPS document was found, specifying that the post-weld heat treatment temperature should be 720 degrees for 60 minutes. In that case, 720–750°C seems more reliable.