武建朝 左世飞 刘思玲 延雨龙

摘要： 从焊接方法及材料的选用、焊接保护气体及热输入控制、组对和预热要求及工艺参数、冬季施工焊前预热4个方面分析了25Cr-7N-4Mo型双相不锈钢的焊接性及注意事项。从焊接环境温度、二次回火及GTAW和GTAW+SMAW的热输入3个方面介绍了25Cr-7Ni-4Mo型双相不锈钢焊接接头组织的控制。结果表明，在北方冬季施工时，GTAW+SMAW的焊接效果优于GTAW;如果在夏季或者南方地区施工，应采取积极的降温措施，来保证焊缝铁素体和奥氏体的占比。正面保护气体宜采用98%Ar+2%N2，背面保护宜采用100%N2来弥补焊接过程N元素流失，更有利于增加焊缝的稳定性;极端寒冷条件建议采取预热措施，避免管道焊接时产生裂纹。

关键词： 双相不锈钢; 25Cr-7Ni-4Mo; 热输入; 焊接接头组织

中图分类号： TG 406

Microstructure of joint and welding quality control of 25Cr-7Ni-4Mo stainless steel

Wu Jianchao， Zuo Shifei， Liu Siling， Yan Yulong

（SHCCIG YuLin Chemical Co.， Ltd.， YuLin 719000， Shaanxi， China）

Abstract： The weldability and precautions of 25Cr-7Ni-4Mo duplex stainless steel were analyzed fromfour aspects of selection of welding method and material， control of welding protection gas and heat input， group pair and preheating requirements and process parameters， preheating before welding in winter construction. The microstructure control of 25Cr-7Ni-4Mo duplex stainless steel welded joint was introduced from three aspects of welding ambient temperature， secondary tempering and heat input of GTAW and GTAW+SMAW. The results showed that the welding effect of GTAW+SMAW was better than that of GTAW in winter construction in north China. However， if the construction was in summer or in the south China， positive cooling measures should be taken to ensure the proportion of weld ferrite and austenite. 98%Ar+2%N2 should be used for the front protection gas， and 100%N2 should be used for the back protection gas to compensate for the loss of N element in the welding process， which was more conducive to increasing the stability of the weld. It was recommended to take preheating measures in extreme cold conditions to avoid cracks in pipeline welding.

Key words：   duplex stainless steel; 25Cr-7Ni- 4Mo; heat input; microstructure of welded joint

0 前言

随着工业4.0的到来，传统制造正在向智能制造转变，我们在享受先进科技技术和工业制造成果的同时也面临着诸多挑战。例如能源问题已成为全人类必须共同面对的难题，煤炭高效清洁转化项目正在逐步代替石油产业成为新的工业基础能源，煤化工也正由基础工业产品向精细化工和集成工业产业集群转变。展望十四五规划，中国的煤化工产业也在工业建设占据了一定比例，然而焊接技术、材料工程技术作为工业建设中必不可少的工序及组成部分，与工业发展相辅相成。双向不锈钢因其独特的焊接性能和材料性能已在煤化工项目中的得到了广泛的应用，同时也成为了工程技术人员一直以来讨论研究的热门课题。……