5Cr型和3Cr—3Mo型热作工具钢的高温强度

STRENGTH AT ELEVATED TEMPERATURE OF HOT-WORKING TOOL STEELS OF 5Cr TYPE AND 3Cr-3Mo TYPE

热作工具钢的高温强度随温度的变化呈明显的两阶段,利用唯象理论对这一现象作了描述。结果表明,可用σ_b=σ_b^o-Cexp(-Q/RT)描述强度随温度变化的趋势。由激活能 Q^(LT)和 Q^(HT)数值推知,在低温阶段回复软化的原因是 Snoek 气团对位错的钉扎作用随温度的升高而减小;在高温阶段回复软化的原因是位错的攀移所致。合金元素对 Q^(HT)有显著的影响。

The strength at elevated temperature is one of the most important proper-ties of hot-working tool steel.The changes of the strength with temperature are obviouslydivided into two stages.This phenomenon is described by a phenomenlogical theory.Theresults show that the tendency of the changes of strength with temperature coincides withthe formula:σ_b=σ_b^0-Cexp(-R/(RT))From Q^(LT),the softening active energy at lower temperature stage,and Q^(HT),the soft-ening active energy at higher temperature stage,it can be derived that the softening at lowertemperature stage is due to the decrease of the effect of Snoek atomsphere on dislocations,and softening at higher temperature stage is owing to the climb of dislocations.It is alsoshown that the alloy elements have a great influence on the Q^(HT).