N含量对17-4PH马氏体时效不锈钢铁素体相和性能的影响

Effect of N Content on Ferrite Phase and Properties of Maraging Stainless Steel 17-4PH

试验用17-4PH不锈钢(/%:0.02～0.03C,0.40～0.54Si,0.41～0.60Mn,0.018～0.026P,0.001S,15. 56～15. 75Cr,4. 31～4. 50Ni,3. 21～3.40Cu,0. 20～0. 25Nb,0. 013～0. 067N)采用20 t EAF+LF+VOD+ESR的工艺冶炼,锻造成Φ150 mm棒材。试验结果表明:钢中N含量由0.013%增加至0.067%时,钢中铁素体含量由0.5%增至6%,钢的强度、硬度升高,塑性降低。当N含量控制在0.020%～0.045%,钢中铁素体含量为1%～3%,经1040℃1 h水冷+480 2 h空冷后,钢的力学性能合格;固溶态钢的HB硬度值≤325,优化了该材料的加工性能。

The tested stainless steel 17-4PH (/%:0.02-0.03C,0.40-0.50Si,0.41-0.60Mn,0.018- 0.026P,0.001S,15.56-15.75Cr,4.31-4.50Ni,3.21-3.40Cu,0.20-0.25Nb,0.013-0.067N)is melted by 20t EAF +LF +VOD +ESR process and forged to Ф150mm bar products.Test results show that with increasing N content in steel from 0.013% to 0.067%,the ferrite content in steel increases from 0.5% to 6%,the strength and hardness of steel increase and the plasticity of steel decreases.As to control the N content in steel 0.020%-0.045%,the ferrite content in steel is 1%-3% and the mechanical properties of steel quenched at 1040℃ for 1h,water cooling +480℃ for 2h,air cooling,the mechanical properties of test steel are qualified;and the HB hardness value of solid-solution-treated steel is ≤325,so the workability of steel is improved.