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设计了一种低合金含量的Q125级高强度石油套管用钢,研究了热处理工艺对实验钢组织和力学性能的影响.与870℃淬火+500℃回火工艺相比,实验钢在850℃淬火+500℃回火工艺下具有更好的强韧性配合.与870℃淬火相比,850℃淬火处理的奥氏体晶粒尺寸较小,使决定钢力学性能的晶区、板条束尺寸细化,因此其性能更优异.淬火温度对实验钢的析出行为影响不大.尺寸较大的TiN以及TiC和TiN复合析出物对奥氏体晶界起到钉扎作用,可以抑制奥氏体晶粒的长大;含有Mo的尺寸较小的TiC可以起到钉扎位错的作用,阻止位错移动,对强度的提高贡献很大.
A low alloy content Q125 grade high strength steel for oil casing was designed to study the effects of heat treatment on microstructure and mechanical properties of experimental steel.Compared with 870 ℃ quenching and 500 ℃ tempering, the experimental steel was quenched at 850 ℃ +500 ℃ tempering process has better strength and toughness compared with the 870 ℃ quenching, 850 ℃ quenched austenite grain size smaller, so that the mechanical properties of the steel crystal area determined, the thin strip size thin , So its performance is more excellent.Quenching temperature has little effect on the precipitation behavior of the experimental steel.The larger size of TiN and TiC and TiN composite precipitates have pinning effect on the austenite grain boundaries and can inhibit the austenite The growth of the grains; the smaller TiC containing Mo can act as a pinning dislocation, preventing dislocation movement and contributing greatly to the increase in strength.