12Cr-1.5W-0.6Si合金管材长期高温蠕变性能研究

Study on Long-Term High Temperature Creep Properties of 12Cr-1.5W-0.6Si Alloy Pipe

为获得铁素体/马氏体合金的高温蠕变性能,采用蠕变试验装置对12Cr-1.5W-0.6Si合金管材开展了450、500和550℃在空气环境下的蠕变试验,获得了蠕变时间-应变曲线和稳态蠕变速率。研究表明:合金的应力指数较高,通过引入门槛应力获得真实应力指数,其蠕变机制是位错攀移机制;经过550℃、160MPa、3145 h蠕变试验后,第二相仍沿晶界分布,但合金出现了板条晶粒宽化、第二相颗粒粗化现象,且长时间蠕变对微观组织的影响更为显著。

To obtain the creep properties of Ferritic/Martensitic alloy,creep tests for 12Cr-1.5W-0.6Si pipes in the air environment at 450°C,500°C and 550°C were carried out to obtain the creep time-strain curve and steady-state creep rate by using the creeptesting device.The results show that the stress index is relatively high,and the true stress index is obtained by introducing threshold stress.The creep mechanism is dislocation climbing mechanism.After creep tests at550°C and 160MPa for 3145 h,the precipitated phase is still distributed along the grain boundary,but the lath grain widens and the precipitated phase grain coarsens,and the effect of long-term creep on the microstructure is more significant.