焊后热处理对双相不锈钢带极堆焊层组织性能的影响

Influence of Post Weld Heat Treatment to Duplex Stainless Steels Overlaying Layer

双相不锈钢在室温下固溶体中奥氏体和铁素体约各占一半且兼有两相组织特征,它保留了铁素体不锈钢强度高,导热系数大,线膨胀系数小,耐点蚀、缝隙腐蚀及氯化物应力腐蚀的特点,又具备奥氏体钢不锈钢韧性好、脆性转变温度较低、抗晶间腐蚀、力学性能和焊接性能好的优点。对2209型双相不锈钢带极堆焊层在焊态及焊后经过690℃下不同时间热处理后堆焊层的组织和性能进行了试验,结果表明,焊后热处理的堆焊层铁素体含量降低、力学性能下降、硬度增高、腐蚀性能下降,这主要是由于堆焊层经热处理后未能保持适当的相比例以及σ相的析出导致的。

Duplex stainless steels are a family of stainless steels having a ferrite-austenite with two phase microstructure,and these steels are characterized by an attractive combination of high strength,high toughness and excellent corrosion resistance.They are used in marine and petrochemical applications.The welding characteristic and technology of duplex stainless steel are introduced.The basic requirement of welding the steel is that the weld metal and heat-affected zone obtain a favorable phase balance and retain the performance as the base metal after welding.An experiment was made for the influence of different post weld heat treatment condition to the SAW overlaying layer.The result declares the ferrite number,mechanical property,corrosion resisting property reduced,hardness risen after post weld heat treatment,this is because phase proportion is destroyed andσphase is produced after post weld heat treatment.