摘要
随着人们对高锰钢材料更高强度、韧性、耐磨性及耐蚀性要求的提出,高氮高锰钢应运而生。目前高氮高锰钢主要采用高压凝固方式生产,成本较高。为此提出在冶炼末期向钢液加入过饱和氮、在钢液凝固时采用快速冷凝方式减少钢液中氮的逸出以控制其氮含量的方法。用高温立式熔炼炉将氮质量分数为0.218%的高氮高锰钢熔化后分别进行空冷和水冷,检测不同冷却条件下高氮高锰钢的氮含量、微观组织和一次枝晶间距等,并建立一次枝晶间距计算模型。结果表明,空冷试样氮质量分数为0.181%、钢中氮逸出率为17%,水冷试样氮质量分数为0.206%、钢中氮逸出率仅为6%;空冷试样的平均一次枝晶间距为63.34μm,水冷试样的平均一次枝晶间距为41.67μm,水冷试样凝固微区较小;空冷试样局部含氮显微气孔较大,并且分布比较集中,呈疏松状态,水冷试样宏观上含氮显微气孔尺寸很小,在20μm以下,且显微气孔数量少;钢液凝固过程中显微气泡的形核长大动力学模型表明,环境压力越高,外界直接抑制力越大,显微气泡越难生成,凝固微区长度越小;一次枝晶间距计算模型表明,随着界面生长速度和温度梯度的增加,枝晶间距逐渐减小,可至50μm以下,钢中凝固微区也减小,有利于抑制氮的逸出。因此对高氮高锰钢进行快速冷凝、减少凝固过程钢液中氮的逸出是提高高锰钢中氮含量的有效方法。
As people put forward higher strength,toughness,wear resistance and corrosion resistance requirements for high manganese steel materials,high nitrogen and high manganese steel came into being.At present,it is mainly produced by high pressure solidification,and the cost is high.Therefore,the method of adding supersaturated nitrogen to molten steel at the end of smelting and reducing the escape of nitrogen in molten steel by rapid condensation during solidification of molten steel was proposed to control its nitrogen content.The high nitrogen and high manganese steel with nitrogen mass fraction of 0.218%was melted in a high temperature vertical melting furnace and then air-cooled and water-cooled respectively.The nitrogen content,microstructure,and primary dendrite spacing of high nitrogen high manganese steel under different cooling conditions were detected,and a calculation model for primary dendrite spacing was established.The results show that the nitrogen mass fraction of air-cooled sample is 0.181%,and the nitrogen escape rate in the steel is 17%,while the nitrogen mass fraction of water-cooled sample is 0.206%,and the nitrogen escape rate in the steel is only 6%.The average primary dendrite spacing of air-cooled sample is 63.34μm,and that of the water-cooled sample is 41.67μm.The solidification micro-region of water-cooled sample is smaller.The local nitrogen-containing micro-bubble of air-cooled sample are larger,and the distribution is more concentrated,showing a loose state.The size of the nitrogen-containing micro-bubble in water-cooled sample is small,below 20μm,and the number of micro-pores is small.The kinetic model of micro-bubble nucleation and growth during solidification of molten steel shows that the higher the ambient pressure,the greater the external direct inhibition force,the more difficult it is to form micro-bubbles,and the smaller the solidification microzone.The calculation model of primary dendrite spacing shows that with the increase of interface growth rate and temperature gradient,the dendrite spacing decreases gradually and can reach below 50μm,and the solidification microzone in steel also decreases,which is beneficial to inhibit the escape of nitrogen.Therefore,rapid condensation of high nitrogen and high manganese steel and reducing the escape of nitrogen from the molten steel during solidification are effective methods to increase the nitrogen content in high manganese steel.
作者
刘吉猛
吕博
赵定国
陈晨
王书桓
张福成
LIU Jimeng;LÜBo;ZHAO Dingguo;CHEN Chen;WANG Shuhuan;ZHANG Fucheng(College of Metallurgy and Energy,North China University of Science and Technology,Tangshan 063210,Hebei,China;School of Environmental and Chemical Engineering,Yanshan University,Qinhuangdao 066004,Hebei,China;State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,Hebei,China)
出处
《中国冶金》
CAS
CSCD
北大核心
2024年第10期58-66,共9页
China Metallurgy
基金
国家自然科学基金资助项目(52171049,52274336)
中央引导地方科技发展资金资助项目(226Z1008G)。
关键词
高氮高锰钢
快速冷凝
氮含量
枝晶间距
氮气泡
high nitrogen and high manganese steel
rapid condensation
nitrogen content
dendrite spacing
nitrogen bubble
