摘要
为了解决P91小直径钢管局部回火后硬度偏低的问题,采用某电厂在役的P91过热器管道,通过正火+回火热处理工艺及硬度对比试验,得到了P91钢不同回火温度后的硬度值;进而对硬度为160HB和180HB的P91钢进行了力学性能试验。结果显示,P91钢出现硬度降低的原因是回火温度过高所致;采用正火1040℃、恒温1~2 min/mm后快速冷却,再通过740~760℃、恒温60 min的回火热处理,各种性能完全满足相关要求。工艺试验及现场检验表明,对于P91小直径管,当不满足换管条件时,可通过正火+回火热处理使管材性能满足要求。
In order to solve the problem of low hardness of P91 small diameter pipe after local tempering,the hardness value of P91 steel after different tempering temperatures was obtained by using P91 steel superheater pipe in service in a power plant through normalizing+tempering heat treatment process and hardness contrast test.The mechanical properties of P91 steel with hardness of 160HB and 180HB were tested.The results show that the reason for the hardness reduction of P91 steel is the high tempering temperature.P91 steel are normalized at 1040℃and kept at constant temperature for 1~2 min/mm,then cooled rapidly,and then tempered at 740~760℃and kept at constant temperature for 60 min.All properties fully meet relevant requirements.The process test and on⁃site construction inspection show that for P91 small diameter pipes,when the pipe replacement can't be realized,the pipe properties can meet the requirements through normalizing+tempering heat treatment,which ensures the construction period and saves corresponding costs.
作者
董春雨
李辉
DONG Chunyu;LI Hui(Tianjin Chengxinda Metal Testing Technology Co.,Ltd.,Tianjin 300380,China)
出处
《焊管》
2023年第2期46-53,59,共9页
Welded Pipe and Tube
关键词
P91钢
热处理
硬度
正火
回火
P91 steel
heat treatment
hardness
normalizing
tempering
