P92钢时效过程中冲击性能和硬度变化的试验

Evolution of Impact Energy and Hardness of P92 Steels During High-temperature Aging Tests

对P92钢在650℃下进行了长达10 000 h的时效试验,并研究了时效过程中P92钢的冲击性能和硬度的变化.结果表明:P92钢具有一定程度的热时效脆化倾向,时效初期脆化速度较快,时效500 h时冲击吸收能量约下降50%,随后放缓并逐渐趋于稳定;根据冲击吸收能量与回火参数之间的变化关系,推出600℃下母材和焊缝金属的时效脆化特性,在整个设计寿命内,虽然母材发生一定程度的时效脆化,但冲击韧性仍然较高;焊缝金属在600℃运行5 000 h时即发生很大程度的脆化,冲击韧性较低;P92钢的硬度随时效时间的增加呈下降趋势,但变化不明显.

A series of aging tests were performed for P92 steel at 650 ℃ with the longest duration up to 10 000 h,so as to study the evolution tendency of its impact energy and hardness.Results show that P92 steel has obvious tendency of embrittlement at early thermal aging stage,its impact absorbed energy drops by 50% at 500 h,but later on tends to be stable.From the aging embrittlement tendency for both the base metal and weld metal at 600℃,extrapolated based on relationship between impact energy and tempering parameters,the base metal is found to have a relatively high impact value over the whole design life,in spite of existence of aging embrittlement.However,for the weld metal,severe embrittlement already occurs at 5 000 h,which results in a low impact value.With the rise of aging time,the hardness of P92 steel drops,but the variation tendency is not obvious.