保持时间对409铁素体不锈钢循环蠕变行为的影响

为了确定保持时间对超纯409铁素体不锈钢循环蠕变行为的影响,通过在应力控制模式下最大外加应力处引入10和30 min的保持时间,对其在650℃下的循环蠕变行为进行了研究.结果表明,与静态蠕变相比保持时间的引入使409不锈钢发生了循环蠕变减速行为,而循环蠕变减速行为可以归因于滞弹性应变.随着保持时间的缩短,最小蠕变速率降低,循环蠕变断裂寿命提高.静态蠕变及循环蠕变后,409不锈钢中有细小的第二相析出,且微观组织以亚晶及四边形和六边形位错网络为主.409不锈钢静态与循环蠕变断裂方式均为穿晶韧性断裂.

Effect of hold time on cyclic creep behavior of 409 ferritic stainless steel

In order to determine the effect of hold time on the cyclic creep behavior of ultra pure 409 ferritic stainless steel, the cyclic creep behavior of 409 stainless steel was investigated at 650 ℃ through introducing 10 min and 30 min hold time at the maximum imposed stress under the stress-controlled mode. The results show that compared with the static creep, the 409 steel exhibits the cyclic creep retardation behavior due to the introduction of hold time, and the cyclic creep retardation behavior can be attributable to the anelastic strain. With decreasing the hold time, the minimum creep rate reduces, while the cyclic creep fracture life increases. After both static and cyclic creep, the fine second-phase particles precipitate in the 409 stainless steel, and the dominated microstructures are sub-grains as well as hexagonal and rectangular dislocation networks. Moreover, the fracture mode of 409 stainless steel after both static and cyclic creep is transgranular ductile fracture.