ODS钢搅拌摩擦焊接头的微观组织及其高温力学性能

Microstructure and mechanical properties in friction stir welded nanostructured oxide dispersion strengthened steel joint

采用搅拌摩擦焊(friction stir welding,FSW)技术对氧化物弥散强化(oxide dispersion strengthen,ODS)铁素体钢进行了焊接,并对焊接工艺进行了优化.当转速为150 r/min,焊接速度为30 mm/min时可以获得无焊接缺陷的ODS钢焊接接头.结果表明,采用FSW焊接的ODS钢接头的微观组织出现明显的洋葱环结构,搅拌区为等轴再结晶晶粒,前进侧热机影响区表现出明显的塑性流动的特征,热影响区的晶粒较母材也发生了明显改变.接头的高温拉伸性能偏低,但经过温度1 150℃,时间1 h的热处理后,其高温拉伸性能得到大幅提高,与母材拉伸性能接近.

The oxide dispersion strengthened( ODS) steelwas joined by friction stir welding( FSW) technique and the optimum friction welding parameter was determined. High quality of welded joints can be obtained when the traverse speed and rotation speed are 150 rpm and 30 mm / min,respectively. Microstructure observation results show that remarkable onion structure appeared in thermo-mechanically affected zone of the advanced side( AS-TMAZ). Equiaxed grain structure was achieved in stir zone. The grains in heat affected zone are quite different from that of the base material. High temperature tensile properties of FSW ODS steel were compared to those of as-received ODS steel and the results indicate that FSW process resulted in a large degradation of the joint strength,while the strength of the joint increases followed by post weld heat treatment at 1 150 ℃ for 1hour.