321不锈钢电弧增材制造构件组织与性能研究

Microstructure and properties of 321 stainless steel fabricated by wire arc additive manufacture

采用3种不同工艺进行321不锈钢电弧增材制造构件打印,借助金相显微镜、扫描电子显微镜研究了焊接速度对电弧增材制造构件组织和力学性能的影响。结果表明:合适的电弧增材制造工艺参数能够保证单道沉积层中无气孔、未熔合及裂纹等缺陷。电弧增材制造321不锈钢的显微组织为奥氏体+δ-铁素体,δ-铁素体呈条状、链状以及岛状分布在奥氏体晶内和晶界处,随着焊接速度的提高,δ-铁素体的数量增加,成形构件的强度先提高后降低,-40℃冲击韧性先降低后提高,其断裂特征为韧性断裂。

Three different processes were used to print 321 stainless steel arc additive components. The effect of welding speed on microstructure and mechanical properties of the components were analyzed by means of optical microscope and scanning electron microscope. The results showed that the appropriate arc additive manufacturing process of 321 stainless steel could ensure that there were no pores, incomplete fusions and crack in the single deposition layer. The microstructure of 321 stainless steel produced by arc additive were austenite+ δ-ferrite. δ-ferrite was distributed in austenite crystal and grain boundary in strip, chain and island shape. With the increase of welding speed, the amount of δ-ferrite increased, and the strength of the formed component was increased first and then was decreased. The impact toughness at-40 ℃ was decreased first and then was increased. The fracture characteristic was ductile fracture.