ABSTRACT

To study the effect of TiN precipitated particles on two end-quenching specimens of 20CrMnTi steel with different hardenability characteristics, the peripheral hardness of the samples is tested. The microstructures, austenite grain structures, characteristics of TiN particles are analyzed. The larger the grain size, the higher the martensite fraction and the higher the hardness. More uniform and more refined grains reduce the maximum peripheral hardness difference of end-quenched samples from 9.1HRC to 3.3HRC. The precipitation of as much fine TiN as possible in the solid phase plays an important role in obtaining more refined and more uniform austenite grains. TiN precipitates less during solidification and more in the solid phase in the sample with better hardenability, promoting grain refinement and more uniform peripheral hardness. In production, with a specific mass fraction of Ti, effectively inhibiting the precipitation of coarse TiN during solidification is the key to control narrow hardenability bandwidth for 20CrMnTi gear steel.

摘要

为研究 TiN 析出颗粒对两种不同淬透性特征的 20CrMnTi 钢端面淬火试样的影响，测试了试样的周边硬度。分析了TiN颗粒的显微组织、奥氏体晶粒结构、特性。晶粒尺寸越大，马氏体分数越高，硬度越高。更均匀和更细化的晶粒将端面淬火样品的最大周边硬度差异从 9.1HRC 降低到 3.3HRC。在固相中析出尽可能多的细TiN对于获得更细化和更均匀的奥氏体晶粒起着重要作用。TiN在凝固过程中析出较少，在试样中的固相析出较多，具有较好的淬透性，有利于晶粒细化，周边硬度较均匀。