土建钢结构用铁素体不锈钢的TIG焊接与腐蚀性能研究

Study on TIG Welding and Corrosion Properties of Steel for Civil Steel Structure

对土建钢结构用铁素体不锈钢进行了TIG焊接处理,研究了焊接电流对焊接接头显微组织和力学性能的影响,并考察了不同腐蚀介质中TIG焊接头的耐腐蚀性能。结果表明,随着焊接电流的升高,焊接接头的抗拉强度和断后伸长率都表现出逐渐降低的趋势,在焊接电流为45A时取得最大值;不同焊接电流下焊接接头都由焊接热影响区、熔合区和焊缝区组成,随着焊接电流的增大,焊接接头宽度、热影响区粗晶区尺寸和焊缝区柱状晶尺寸有所增加;当腐蚀介质为3.5%NaCl时,焊接头的耐蚀性能与母材相当或者略低;当腐蚀介质为3.5%NaOH溶液时,焊接头的耐腐蚀性能明显低于母材;铁素体不锈钢TIG焊接接头不适于在碱性条件下使用。

The TIG welding of ferritic stainless steel for civil steel structure was carried out.The effect of welding current on the microstructure and mechanical properties of the welded joint was studied,and the corrosion resistance of the TIG welded joint in different corrosive media was investigated.The results show that with the increase of welding current,the tensile strength and elongation of welded joints shows a decreasing trend,and the maximum values of tensile strength and elongation are obtained when the welding current is 45 A.The welded joint is composed of welding heat affected zone,fusion zone and weld zone under different welding currents.With the increase of welding current,the width of welded joint,the sizes of coarse grain zone of heat affected zone and columnar grain of weld zone increase.When the corrosion medium is 3.5%NaCl,the corrosion resistance of welded joint is equivalent to or slightly lower than that of base material,and when the corrosion medium is 3.5%NaOH solution,the corrosion resistance of welded joint is obviously lower than that of the base material.Ferritic stainless steel TIG welded joints are not suitable for use under alkaline conditions.