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焊接接头的耐腐蚀性受焊接热循环的作用,引起焊缝增碳和元素的偏析,焊缝和 HAZ 的Cr_(23)C_6析出及δ→γ′+σ的转变。减少钢中和焊缝的含碳量(≤0.03%)能大幅度改善耐蚀性。奥氏体不锈钢对热裂纹有很高的敏感性,通过控制钢中和焊缝中的杂质和合金元素的含量以及使用含有少量铁素体的不锈钢焊条或焊丝,可以防止热裂纹。焊接接头的脆化是纯铁素体不锈钢的主要问题,减少钢中和焊缝中的 C、N(C+N≤150ppm)可以改善焊接接头的塑韧性。如果使用超低碳奥氏体焊条,焊缝将不发生脆化。α+γ双相不锈钢焊接接头有优良的耐应力腐蚀破裂,点蚀等性能,这取决于钢材和焊缝的原始奥氏体数量,采用某些含少量δ-铁素体的奥氏体钢焊条或焊丝,焊缝有优良的性能,当[Ni]和[Cr]的当量值之比约为0.42时,在 HAZ 的性能是满意的。
The corrosion resistance of the welded joint is affected by the heat cycle of the welding, causing the carbon sequestration and element segregation of the weld seam, the precipitation of Cr 23 C 6 and the transformation of δ → γ ’+ σ in the weld and HAZ. Reducing the carbon content of steel and weld (≤0.03%) can greatly improve the corrosion resistance. Austenitic stainless steels are highly susceptible to hot cracking. Hot cracking can be prevented by controlling the amount of impurities and alloying elements in the steel and in the weld, as well as using stainless steel electrodes or wires that contain small amounts of ferrite. Embrittlement of welded joint is the main problem of pure ferritic stainless steel. Reducing the C and N (C + N≤150ppm) in the steel and in the weld can improve the plasticity and toughness of the welded joint. Welds will not embrittle if ultra-low carbon austenitic electrodes are used. α + γ duplex stainless steel welded joints have excellent resistance to stress corrosion cracking, pitting and other properties, depending on the original austenitic steel and weld number, the use of some containing a small amount of δ-ferrite austenitic steel Electrodes or wires, the weld has excellent performance, when the equivalent ratio of [Ni] and [Cr] is about 0.42, the performance of the HAZ is satisfactory.