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研究了氮细化新型高导热性奥氏体锰钢晶粒度的作用机理.结果表明,铸态奥氏体锰钢中氮在固液界面形成吸附层,阻碍铁、锰、碳等原子的扩散,提高了形核过冷度和形核自由能差,提高均质形核率,降低晶体长大速度,使晶粒细化;氮在晶界固溶,与晶界处铁、锰等原子形成较强的共价键,牵制了铁、锰原子的扩散,使晶粒在热处理过程长大受阻,限制了奥氏体锰钢晶粒度长大,细化晶粒.细化效果还与氮浓度有关.新型试验钢种锰含量降至不高于8%,碳含量约1%,氮含量约0.07%,晶粒度达到4级,机械性能达到甚至超过标准高锰钢Mn13.
The mechanism of nitrogen refinement of the grain size of a new type of high thermal conductivity austenitic manganese steel was studied.The results show that the nitrogen in as-cast austenitic manganese steel forms an adsorption layer at the solid-liquid interface and hinders the formation of iron, manganese and carbon atoms Diffusion, improve the nucleation undercooling and nucleation free energy difference, improve the homogeneous nucleation rate, reduce the crystal growth speed, grain refinement; nitrogen in the grain boundary solution, and the grain boundaries of iron, manganese and other The formation of a strong atomic covalent bond, containing the proliferation of iron and manganese atoms, the growth of the grain in the process of heat was blocked, limiting the austenitic manganese steel grain size growth, grain refinement. Which is related to the nitrogen concentration.The new test steel has a manganese content of less than 8%, a carbon content of about 1%, a nitrogen content of about 0.07% and a grain size of 4 and the mechanical property meets or exceeds the standard high manganese steel Mn13.