超高氮奥氏体钢的铸态组织研究
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摘要
采用Thermo-Calc软件对超高氮奥氏体钢的伪二元平衡相图进行热力学计算。通过金相显微镜、扫描电镜和XRD,研究了实验用钢的铸态显微组织。结果表明:氮含量为0.9wt%的奥氏体钢的固相线和液相线温度分别为1310、1440℃。氮化物Cr_2N的析出温度区间为907～1080℃;碳化物M_(23)C_6的析出温度在900℃。超高氮奥氏体钢的铸态组织的基体为奥氏体,析出的氮化物有的呈球状和不规则块状弥散在晶内,有的呈长条状、絮状和块状沿晶界析出。
Thermo-Calc software was used to calculate the pseudo-binary equilibrium phase diagram of ultra-high nitrogen austenitic steel. The as-cast microstructure of the test steel were observed by metallographic microscope, scanning electron microscope and XRD. The results show that the solidus and liquidus temperature of the austenitic steel with a nitrogen content of 0.9 wt% is 1310 ℃ and 1440 ℃, respectively. The precipitation temperature range of the nitride Cr_2N is between 907 ℃ and 1080 ℃, and the precipitation temperature of carbide M__(23)C_6 is 900 ℃. The matrix of as-cast microstructure of the ultra-high-nitrogen austenitic steel is austenite, and some of the precipitated nitrides are scattered in the form of spheres and irregular blocks, and some are elongated, floc and block precipitating along the grain boundary.
Thermo-Calc software was used to calculate the pseudo-binary equilibrium phase diagram of ultra-high nitrogen austenitic steel. The as-cast microstructure of the test steel were observed by metallographic microscope, scanning electron microscope and XRD. The results show that the solidus and liquidus temperature of the austenitic steel with a nitrogen content of 0.9 wt% is 1310 ℃ and 1440 ℃, respectively. The precipitation temperature range of the nitride Cr_2N is between 907 ℃ and 1080 ℃, and the precipitation temperature of carbide M__(23)C_6 is 900 ℃. The matrix of as-cast microstructure of the ultra-high-nitrogen austenitic steel is austenite, and some of the precipitated nitrides are scattered in the form of spheres and irregular blocks, and some are elongated, floc and block precipitating along the grain boundary.
引文
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[6]Ha H,Kwon H.Effects of Cr2N on the pitting corrosion of high nitrogen stainless steels[J].Electrochimica Acta,2007,52(5):2175-2180.
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[9]Wang Z H,Sun S H,Wang B.Effect of grain size on dynamic recrystallization and hot-ductility behaviors in high-nitrogen Cr Mn austenitic stainless steel[J].Metallurgical and Materials Transactions,2014,45A:3631-3639.
[2]Wang Z,Fu W,Sun S,et al.Effect of preheating temperature on surface cracking of high nitrogen Cr Mn austenitic stainless steel[J].Journal of Materials Science&Technology,2010,26(9):798-802.
[3]Lang Y P,Zhou Y,Rong F,et al.Hot Working of High Nitrogen Austenitic Stainless Steel[J].Journal of Iron and Steel Research,International,2010,17(10):45-49.
[4]李荣红.300MW护环的制造工艺研究[J].热加工工艺,2012,41(19):156-158.
[5]Gavriljuk V,Petrov Y,Shanina B.Effect of nitrogen on the electron structure and stacking fault energy in austenitic steels[J].Scripta Materialia,2006,55(6):537-54
[6]Ha H,Kwon H.Effects of Cr2N on the pitting corrosion of high nitrogen stainless steels[J].Electrochimica Acta,2007,52(5):2175-2180.
[7]杨兵,曲东方,郭宝强,等.600MW 1Mn18Cr18N护环的制造[J].大型铸锻件,2010(6):31-34.
[8]张荣华.护环用改进型超高氮奥氏体钢的铸态组织及热变形行为[D].燕山:燕山大学,2015
[9]Wang Z H,Sun S H,Wang B.Effect of grain size on dynamic recrystallization and hot-ductility behaviors in high-nitrogen Cr Mn austenitic stainless steel[J].Metallurgical and Materials Transactions,2014,45A:3631-3639.