Analysis and Control on Fracture of 20Mn2A High Tensile Steel for Round Link Chain

Based on the phenomenon of brittle fracture occurred during tensile test for 20Mn2A high strength circular chain used in coal mines,the fracture property is regarded as intercrystalline brittle one after macroscope observation and metallographic examination.It is analysed that the intercrystalline brittle fracture is due to high tempering temperature and limited processing site where final products are piled together after heat treatment,which lead to a lower cooling rate of internal chain,with Si,Mn and P etc elements segregating and enriching in the austenite grain boundary and forming high tempering brittleness.After these circular chains are tempered again for one hour at 670℃,and oil-cooled rapidly,due to the reversibility of high temper brittleness for structural alloy steel,the high temper brittleness can be eliminated and products are completely qualified after tensile inspection.

高强度矿用圆环链23MnNiMoCr54钢的研发与应用

对23MnNiMoCr54钢采用Gleeble3500热模拟机、TEM及SEM等试验方法进行基础数据分析及成分设计优化,通过制定合理的冶炼、轧制及退火工艺,成功开发出高强度矿用圆环链用钢。分别向用户提供试制的成品钢材样钢,样钢通过测试其各项指标均达到了GB/T 10560—2017规定的C级圆环链的要求。