带极电渣堆焊奥氏体不锈钢耐晶间腐蚀性能

用带极电渣堆焊和带极埋弧堆焊2种方法堆焊了Cr-Ni不锈钢，研究了这两种方法和焊接速度对堆焊层金属显微组织及耐晶间腐蚀性能的影响。显微组织观察表明，带极电渣堆焊和带极埋弧堆焊层的显微组织都为奥氏体+δ铁素体。带极电渣堆焊层金属中δ铁素体随着焊速的提高而增多，含量由6。8%增加到20.4%，带极埋弧堆焊金属中的δ铁素体含量比带极电渣堆焊的高，达到了23.6%；电化学动电位再活化试验结果表明，焊接速度8m/h的带极电渣堆焊层金属的再活化率仅为3.22%，耐晶间腐蚀的性能最佳，焊速快慢或焊接方法改变都将使带极电渣堆焊层金属的再活化率升高，耐晶间腐蚀性能下降。10%草酸溶液电解浸蚀试验的结果与EPR曲线结果一致。

Study of intergranular corrosion resistance of overlay by Electroslag cladding with austenitic stainless steel

The welding joints were obtained through surfacing the Cr-Ni stainless steel on Q235 by ESW (electroslag strip cladding) and SAW (submerged arc welding). The influence of these two methods and welding speeds on microstructures and intergranular corrosion resistance of overlays was researched. The microstructures of overlays cladded by ESW and SAW are austenitic combinated with δ-ferrite. With the increasing of welding speed of ESW, the δ-ferrite content of overlays increases from 6.8% to 20.4%; While the δ-ferrite content of SAW surfacing mental is the highest in all samples, reaching 23.6%. EPR (Electrochemical Potentiodynamic Reactivation) test shows that the re-activating rate (Ra) of overlay cladded by ESW with the welding speed v=8m/h is the lowest, just only 3.22%, which indicates the best performance of anti-intergranular corrosion. Changing welding speed or method will rapidly increase Ra, resulting in a decrease of the resistance of intergranular corrosion. The results of 10% oxalic acid electrolytic etching test are the same as EPR.