管板带极电渣堆焊双相不锈钢工艺  

Overview of surfacing duplex stainless steel on tubesheets by electroslag strip welding

作　　者：邢卓[1] XING Zhuo(Shenyang Academy of Instrumentation Science Co.,Ltd.,Shenyang 110168,China)

机构地区：[1]沈阳仪表科学研究院有限公司,沈阳110168

出　　处：《压力容器》2024年第11期74-84,共11页Pressure Vessel Technology

摘　　要：为了提高管板的耐蚀性,需要在管板上堆焊耐蚀合金。选择合适的焊接材料和堆焊工艺是获得奥氏体(γ)和铁素体(δ)两相平衡的双相不锈钢堆焊层的关键。双相不锈钢的铁素体含量高,堆焊层不能进行常规的600~900℃的消除应力热处理。当管板材料的淬硬性较高,需要焊后热处理时,应以奥氏体不锈钢作为过渡层,过渡层堆焊后进行热处理。双相不锈钢的线膨胀系数与碳素钢或低合金钢接近,适于在焊接性较好的管板上直接堆焊,可不需要过渡层,也不能进行常规的消除应力热处理。通过试验检测和应用实例说明,带过渡层和不带过渡层的焊接工艺均适用于管板堆焊,工艺适宜均可获得40%以上的铁素体堆焊层,其具有良好的综合性能。The tubesheet is a critical pressure-bearing component in heat exchangers,typically thick and predominantly made from carbon steel or low-alloy steel.To enhance corrosion resistance,corrosion-resistant alloys are often surfacing-welded onto the tubesheet.Duplex stainless steel is widely used in the surfacing of heat exchanger tubesheets due to its high strength and exceptional resistance to stress corrosion cracking.The selection of appropriate welding materials and surfacing processes is key to achieving a balanced austenitic(γ)and ferritic(δ)two-phase structure in the duplex stainless steel surfacing layer.Because of the high ferrite content in duplex stainless steel,harmful phases may precipitate from the ferrite at elevated temperatures,significantly degrading the material's overall performance.Therefore,conventional stress relief heat treatments in the range of 600℃to 900℃cannot be applied to duplex stainless steel surfacing layers.When the tubesheet material has high hardenability and post-welding heat treatment is required,austenitic stainless steel should be used as a transition layer,and heat treatment should be performed after the transition layer is surfacing-welded.The linear expansion coefficient of duplex stainless steel is similar to that of carbon steel or low-alloy steel,allowing for direct surfacing welding onto tubesheets with good weldability.In such cases,no transition layer or conventional stress relief heat treatment is needed.Experimental comparisons and practical applications demonstrate that both welding processes with and without a transition layer are suitable for tubesheet surfacing.If the process parameters are properly selected,a surfacing layer with a ferrite content of over 40%can be achieved,ensuring excellent overall performance.Notably,the surfacing process without a transition layer offers significant advantages and should be prioritized whenever conditions permit.

关 键 词：双相不锈钢 管板 带极堆焊 电渣堆焊 过渡层 热处理 

分 类 号：TH142[一般工业技术—材料科学与工程] TG142.71[机械工程—机械制造及自动化] TG448[金属学及工艺—金属材料]