残余元素对20CrMoA钢的组织与硬度的影响

The Effect of Residual Elements on the Structure and Hardness of 2oCrMoA

通过对比分析20CrMoA化学成分、冶炼工艺、轧制工艺及成品组织与性能的关系,发现20CrMoA硬度超标与化学成分中残余B及N含量有关,当残余B含量超过2×10^(-6)且N低于50×10^(-6)时,20CrMoA成品会出现大量贝氏体组织,造成硬度超标,此时残余B含量对钢材淬透性也会产生一定的影响。冶炼过程通过控制加入合金中残余B含量,将成品中残余B控制在2×10^(-6)以内,当钢水中B含量>2×10^(-6)时,通过RH吹N工艺将N含量控制在50×10^(-6),成品金相组织中贝氏体含量较少,硬度可控制在160~190 HBW,且钢材淬透性稳定性得到提高。

This article compares and analyzes the relationship between the chemical composition,smelting process,rolling process,and finished product structure and properties of 20CrMoA.It is found that the excessive hardness of 20CrMoA is related to the residual B and N content in the chemical composition.When the residual B content exceeds 2×10^(-6)and N below at 50×10^(-6),a large amount of Bainite structure will appear in the 20CrMoA finished product,causing the hardness to exceed the standard.At this time,the residual B content will also have a certain impact on the hardenability of the steel.The smelting process controls the residual B content in the added alloy to in the finished product within 2×10^(-6),when the content of B in steel water is greater than 2×10^(-6),control the N content to through the RH blowing N process 50×10^(-6),the content of Bainite in the finished metallographic structure is less,the hardness can be controlled between 160-190 HBW,and the hardenability stability of the steel is improved.