新型9%~12%Cr马氏体耐热钢控氮工艺研究  

Study on Nitrogen Content Control Process for New Type of 9%~12%Cr Martensitic Heat-resistant Steel

作　　者：彭雷朕 徐超 于梦圆 沈国劬 陈光 罗玉立 班兆伟 杨先芝 陈道琪 廖凯 高祥 PENG Leizhen;XU Chao;YU Mengyuan;SHENGuoqi;CHEN Guang;LUO Yuli;BAN Zhaowei;YANG Xianzhi;CHEN Daoqi;LIAO Kai;GAO Xiang

机构地区：[1]二重(德阳)重型装备有限公司,四川德阳618013 [2]大型铸锻件先进制造技术及装备国家工程研究中心,四川德阳618013 [3]四川省先进极限制造技术创新中心,四川德阳618013 [4]中国联合重型燃气轮机技术有限公司,北京100000

出　　处：《大型铸锻件》2025年第2期14-18,共5页Heavy Casting and Forging

基　　金：XX集团公司科研项目(H036)。

摘　　要：9CrMoCoVBN耐热钢是我国自主设计的一种新型9%~12%Cr马氏体耐热钢,其高强高韧性满足高等级重型燃气轮机轮盘服役要求。钢中[N]形成细小弥散分布MX相,高温稳定性强,同时加入适量[B],生成M_(23)(C,B)_(6)相,抑制碳化物在服役温度下长大粗化。但[B]控制范围窄,且B易与N形成BN夹杂。因此,为充分发挥钢中B、N强化作用,同时避免BN析出,需要严格控制钢中[N]。本文主要通过对气相渗氮过程中渗氮温度、渗氮压力对钢液中[N]影响及避免浇铸过程中气孔缺陷形成的浇铸工艺等研究,制定合理的气相渗氮工艺及浇铸工艺。研究发现,9CrMoCoVBN耐热钢在渗氮温度为1550℃时可实现快速渗氮,渗氮压力为5、10、15、20、25 kPa时,可实现钢液中N含量为0.013%、0.021%、0.03%、0.037%和0.044%;含N钢在浇铸凝固过程中,为避免产生气孔缺陷,一般应采用加压浇铸,浇铸压力应小于或等于钢中N含量对应的平衡N_(2)分压,即可实现控制凝固过程中钢锭N含量变化,同时避免钢锭中出现气孔缺陷。9CrMoCoVBN heat-resistant steel is a new type of 9~12%Cr martensitic heat-resistant steel designed independently by our country,and its high strength and high toughness can meet the service requirements of high-class heavy gas turbine disc.[N]content in the steel forms fine diffusion distribution of MX phase,with good stability at high temperature.In the meantime,adding an appropriate amount of[B]and generating M_(23)(C,B)_(6) phase will inhibit the growth and coarsening of carbide at the service temperature.However,the control range of[B]is narrow,and B is easy to form BN inclusions with N.Therefore,the[N]content in the steel needs to be strictly controlled so that the reinforcing effect of B and N in steel can be fully utilized and BN precipitation can be avoided.In this paper,the influence of nitriding temperature and pressure on[N]in molten steel during the gas phase nitriding process and the casting process to avoid the formation of porosity defects during the casting process are studied,and the reasonable gas phase nitriding process and casting process are formulated.It has been found through the research that 9CrMoCoVBN heat-resistant steel can undergo rapid nitriding at a nitriding temperature of 1550℃.When the nitriding pressure is 5,10,15,20,and 25 kPa respectively,the wN in the molten steel can reach 0.013%,0.021%,0.03%,0.037%,and 0.044%.During the casting and solidification process of N-containing steel,pressure casting is generally employed so that the formation of porosity defects can be avoided.The casting pressure shall be less than or equal to the equilibrium N_(2) partial pressure corresponding to the N content in the steel,which can control the variation of N content in the ingot during the solidification process and simultaneously prevent the occurrence of porosity defects in the ingot.

关 键 词：9CrMoCoVBN钢 气相渗氮 气孔缺陷 

分 类 号：TF702.9[冶金工程—钢铁冶金]