F/M钢包壳管材热处理工艺优化

通过对Fe-12Cr-1.5W-0.2V-0.15Ta F/M钢包壳管材分别进行980~1150 ℃正火和600~730 ℃回火处理,研究不同热处理工艺对包壳管材微观组织、室温力学性能的影响。结果表明,不同温度正火处理后,F/M钢包壳管材的组织均为板条马氏体,随正火温度的升高,粗大的碳化物颗粒逐渐固溶至基体中,且原奥氏体晶粒尺寸会产生粗化,从1050 ℃的40 μm增至1150 ℃的80 μm;不同温度回火后,马氏体基体上析出细小纳米级碳化物颗粒,随回火温度增加,碳化物颗粒析出数量明显增加,但析出的碳化物颗粒尺寸无明显变化;包壳管材经过1100 ℃×60 min正火+650 ℃×90 min回火后具备良好的微观组织和力学性能,其原始奥氏体晶粒无明显长大,马氏体板条组织平均晶粒尺寸约为6.0 μm,小角度晶界比率为59.6%,沿着原奥氏体晶界有纳米相析出,晶内马氏体界面处析出大量纳米相,此时,管材表现出良好的强塑性匹配,抗拉强度为1024 MPa、屈服强度为849 MPa、伸长率为17.3%。

Optimization of heat treatment process for F/M steel cladding pipes

Effects of different heat treatment processes on microstructure and room temperature mechanical properties of Fe-12Cr-1.5W-0.2V-0.15Ta F/M steel cladding pipes were studied by normalizing at 980-1150 ℃ and tempering at 600-730 ℃. The results show that, after normalizing at different temperatures, the microstructure of F/M steel cladding pipes is lath martensite, while with the increase of normalizing temperature, the coarse carbide particles will gradually dissolved into the matrix, and the grain size of the prior austenite coarsens from 40 μm at 1050 ℃ to 80 μm at 1150 ℃. After tempering at different temperatures, fine carbide nanoparticles precipitate in the martensite matrix, and the amount of carbide particles increases significantly with the increase of tempering temperature, but the size of carbide particles does not change obviously. After normalizing at 1100 ℃ for 60 min and tempering at 650 ℃ for 90 min, the cladding pipes have good microstructure and mechanical properties, original austenite grains do not grow obviously, and the average grain size of martensite laths is about 6.0 μm, the ratio of small angle grain boundary is 59.6%, the nano-phase precipitate along the original austenite grain boundary, and a large number of nano-phases precipitate at the interface of intragranular martensite, at this time, the pipes show good strong plastic matching, the tensile strength is 1024 MPa, the yield strength is 849 MPa and the elongation is 17.3%.