不锈钢带极电渣堆焊层金属耐腐蚀性能

Corrosion resistance of overlay by electroslag cladding with stainless steel strip

关键词:  带极电渣堆焊  堆焊层金属  耐腐蚀性能

Key words:  electroslag strip cladding  cladding overlay  corrosion property

摘要:

采用带极电渣堆焊(ESW)和带极埋弧堆焊(SAW)两种方法在Q235母材上熔敷不锈钢层,分析了这两种方法和不同焊接速度下得到的堆焊层金属的电化学腐蚀及晶间腐蚀性能.电化学腐蚀结果表明,9.8%H₂SO₄溶液中,当扫描电位低于-300 mV时,堆焊层金属即可进入钝化状态,堆焊层金属(ESW v=8 m/h)的电化学腐蚀性能最佳;5%HCl溶液中,由于穿透性强的Cl^-使堆焊层表面形成的钝化膜溶解破坏,导致堆焊层金属在扫描电位-800~200 mV范围内处于活化状态,发生点腐蚀.10%草酸溶液晶间腐蚀试验表明,带极电渣堆焊层金属的抗晶间腐蚀性能明显优于带极埋弧堆焊层金属.

Abstract:

Both electrochemical corrosion and intergranular corrosion properties of overlays on base metal Q235 obtained by electroslag strip cladding(ESW) and submerged arc welding (SAW) were studied. Electrochemical corrosion experiments showed that overlays got into passive state when scanning potential was below - 300 mV, and electrochemical corrosion property of overlay by ESW (overlay speed v=8 m/h) is the best in 9.8% H₂SO₄. Due to passive film destroyed by Cl^-, overlays were in activated stage within the scanning potential range of - 800- 200 mV, and pitting corrosion occurred. Intergranular corrosion property of overlay by ESW is obviously superior to the overlay by SAW in 10% oxalic acid solution.