Study on Bainitic Transformation Behavior of 25MnV Steel

The bainitic transformation behavior of the 25MnV steel is studied with the expansimeter method and under two experimental process conditions as simulating rolling and rolling-control & cooling-control process conditions for seamless steel tube manufacture. The result shows that with higher rolling-end temperature,after getting the material quickly cooled down to 390~485 ℃,and then subjected to slow cooling,full bainitic structure with hardness higher than 22HRC is formed,which leads to such a conclusion that it is possible to produce the bainitic N80 steel oil casing with the rolling-control & cooling-control process. The research achievement provides basis for development of the non-quenched-and-tempered bainitic steel tube.