304L不锈钢氩弧焊接工艺特点及常见缺陷的防治措施..docx

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1、第34卷第3期陈连山，陈兵辉，安金平（中国石油自然气管道三公司，河南中牟451450摘要:304L不锈钢（ASTM标准为奥氏体不锈钢，属于超低碳级不锈钢，具有 良好的综合性能，是目前工业上应用最广泛的不锈钢。文章通过现场实际操作，探讨总结了 304L不锈钢焊接的工艺特点，针对晶间腐蚀、层间未熔合、引弧夹鸨、收弧缩孔 等问题提出了详细的解决方法和留意事项，有效地解决了焊接质量问题。关键词： 奥氏体不锈钢；晶间腐蚀；危急温度区；焊接线能量中图分类号:TG444.74TG457. il 文献标识码:B 文章编号：1001-2206（2023 03-0049-02304L不锈钢筑弧焊接工艺特点及常见缺

2、陷的防治措施11111 f 1111! II1111111111 西气东输管道增输工程压缩机（组中的润滑油系统、干气密封系统和前置加热系统的工艺管道均为不锈钢管，材 质为304L不锈钢（美国ASTM标准，主要管道规格为D60mm x6mm ;本文主要以D60mm x6mm 管道为例，分析奥氏体不锈钢管道焊接中易发生的缺陷，并介绍实行的预防措施。1304L不锈钢的特性和焊接工艺参数奥氏体不锈钢304L对应我国的标准是00Crl9Nil0,其主要化学成分和机械性能见表lo304L不锈钢的热导率较低，约为碳钢的1/3,电阻率约为碳钢的5倍，线膨胀系 数比碳钢约大50%,密度大于碳钢。由于不锈钢存在众

3、多与碳钢不同的特性，其焊接工艺规范也与碳钢有所不同，对于304L不锈钢钢管 （D60mm x6mm我们采用的焊丝为ER308L ,焊接工艺参数见表2O2304L不锈钢焊接工艺特点2.1晶间腐蚀及应对措施晶间腐蚀是在腐蚀介质作用下，起源于金属表面的晶界并且沿晶粒边界深化 金属内部产生在晶粒之间的一种腐蚀。晶间腐蚀是奥氏体不锈钢常见的焊接缺陷。Cr是奥氏体不锈钢中具有耐腐蚀性的基本元素，当Cr含量低于12%时，就不再具有耐腐蚀性了。304L不锈钢在焊接过程 中存在焊接危急温度区间（为450 850 ,见图1。当温度达到这一范围时，奥氏体中过饱和的碳向晶界处快速扩散并在晶粒边界析出，析出 的碳和铭形

4、成碳化铭（Cr 23C 6。因为铭在奥氏体中的扩散速度很慢，来不及 向晶界扩散，这样就大量消耗了晶界处的貉，使晶界处含貉量降低到小于12%,这 时晶界就失去了耐腐蚀实力。假如温度低于450 ,则奥氏体中的碳扩散速度不 快，不能在晶界处扩散析出而形成碳化络，所以没有晶间腐蚀现象。假如温度高 于850 ,这时不仅碳在奥氏体中的扩散速度极快,而且铭在奥氏体中的扩散速度 也很快，故不能造成晶粒边界处贫铭，因而也不会发生晶间腐蚀。为防止304L不锈钢在焊接过程中耐腐蚀性能下降，可以实行以下几点措施：表1304L不锈钢的化学成分和机械性能化学成分及含量/%机械性能CCr Ni屈服强度/MPa抗拉强度/MP

5、a硬度HB 205520 187表2304L不锈钢的焊接工艺参数焊层焊丝直径/mm电流/A电压/V焊接速度/(mm/min根焊2.09。 958-10605填充盖帽2.4110 12023- 12605注:焊接坡口角度为75。5。石油工程建设49石油工程建设2023年6月(1焊接时在管道内部进行充氨施工，并且确保根焊时充筑浓度达到92%以 上。在填充、盖帽焊时，也要进行充氨，防止焊缝金属在高温时进行氧化反应，造 成晶间腐蚀。(2焊接时采纳小电流，快速焊，降低焊接线能量，缩短奥氏体不锈钢在危急 温度区间(450-850的停留时间,防止晶间腐蚀。(3对有条件进行热处理的焊缝，在焊接后可以进行快速冷

6、却，使焊缝温度低 于450C,防止晶间腐蚀。2.2层间未熔合的解决方法相对于碳钢，不锈钢在熔化后黏度大，流淌性差，简单形成层间未熔合等缺陷。为此在焊接时相应地增大焊缝坡口角度， 便于熔敷金属流淌，通常坡口角度为7550另外在根焊中尽量采纳小直径焊丝，小电流，降低焊接线能量，提高熔敷金属的流淌性。2.3 采纳专用筑弧焊机，克服引弧夹鸨和收弧缩孔不锈钢焊接易产生引弧夹鸨 和收弧缩孔，需要配备具有高频引弧和电流衰减特性的专用氮弧焊机，高频引弧可以削减焊接 夹鸨，电流衰减可以削减收弧缩孔。2.4 采纳单侧连续送丝方式不锈钢焊接中，对于焊口组对间隙较大的焊缝，采纳单侧连续送丝方式（见图2 ,焊枪连续摇摆

7、，焊丝只在一侧缓缓送入， 靠液态金属流淌性与另一侧熔化母材结合，这样可以防止根焊内部的单侧咬边问 题，改善内部成型。2.5 采纳多层焊接方式由于不锈钢焊接存在危险温度区间，在焊接过程中尽量采纳多层焊接，每层熔敷金属尽量薄，在前一层焊缝冷却后再进行 下一层焊接（冷却温度应低于60。焊缝尽可能一次焊完，少中断，少接头，收弧要衰减。盖面以 焊缝外观黄、红为宜，若出现金属黑则表示焊接线能量过大。2.6 采纳小热量输入、小电流快速焊不锈钢焊接中采纳小热量输入、小电流快速焊。焊丝不做横向摇摆，焊道宜窄不宜宽，最好不超过焊丝直径的3倍， 这样焊缝冷却速度快，在危急温度区间停留时间短，有利于防止晶间腐蚀。小

8、热量输入时，焊接应力小，有利于防止应力腐蚀和热裂纹，而且焊接变形小。3留意事项（1焊接前要检查筑气浓度。不锈钢筑弧焊的负气浓度需达到99.9%以上，这 样可以起到爱护作用，防止出现焊接缺陷。(2在焊接前要确定管道内充氮的浓度。不锈钢焊接前管道内须要充氮，且充 筑浓度需达到92%以上，充氮浓度可以通过仪器检测或者在管道焊口引弧确定。(3焊接后要对焊缝表面和内部进行酸洗钝化处理。经过钝化处理的焊缝表 面呈银白色，具有较高的耐腐蚀性。4结束语通过现场实践和多次改进，很好地解决了304L不锈钢焊接中常出现的缺陷问题，焊接一次合格率达到98%以上。参考文献：1中国石油自然气集团公司人事服务中心.电焊工M

9、.东营：中国石油高校出版社，2023.2高忠民.电焊工基本技术M.北京:金盾出版社，2000.3中国机械工程学会焊接学会.焊接手册M.北京:机械工业出版社，2023.作者简介：陈连山(1963-,男，辽宁葫芦岛人，高级工程师，毕业于中国石油高 校，从事油气管道项目及技术管理工作。收稿日期:2023-11-05850危急温度上限450 C危急温度下限丢失抗晶间腐蚀能力的区域加热温度保温时间图1加热温度和保温时间对18-8钢抗晶间腐蚀实力的影响图2单侧连续送丝方式焊枪不锈钢焊丝焊件1焊件250(41 Force Analysis and Calculation of Steel Frame Use

10、d as Hoisting AssistanceMO Jin-yong (Maoming Southwest Petrochemical Engineering Construction Co. Ltd., Maoming 525011, ChinaAbstract:The first regenerator of a catalytic unit was difficult to be hoisted because of its large mass over 800t. Through comparing several hoisting scenarios, an ingenious

11、solution was chosen, that was taking the stair frame near the generator as a support and fixing a small mast on it to carry out the generator hoisting op-eration with its subsections. This paper gives the analysis and calculation methods of the forces acting on the stairframe that is the key structu

12、re to this hoisting operation. This method has a practical value to similar hoisting work.Key words:equipment hoisting; frame structure; finite element method; force analysis and calculation (46 Design and Application of 500t Level Non-eccentric Hoisting BeamLI Guan-xu (CNPC No. 1 Construction Co.,

13、Luoyang 471023, China , ZHANG Jing- biao , YANG Sen , et al. AbstractJn large equipment hoisting operations, hoisting beam is often used as an important construc-tion tool. Its reasonable design and application are directly related to the safety, economy and efficiency of hoisting operation. A desig

14、n method and its applied instance of a non-eccentric hoisting beam are illustrated. With this design method, the structure of the hoisting beam can be more reasonable with remarkably decreased added weight, low manufacture cost and reduced hoisting difficulty.Key words:hoisting; non-eccentricity; ho

15、isting beam; design WELDING TECHNOLOGY (49 Technological Features of 304L Stainless Steel Argon Arc Welding and Defect Prevention Measures CHEN Lan-shan (CPP No.3company, Zhongmu 451450, China , CHEN Bing-hui, AN Jin-ping Abstract:304L stainless steel (ASTM standard , as an austenitic stainless stee

16、l with ultra-low carbon, has excellent synthetic functions and is the most widely applied stainless steel in the world. Based on the site practice and research work, this paper summarizes the technological features of 304L stainless steel welding, and puts forward concrete methods and matters for at

17、tention to resolve welding problems such as intergranular corrosion, interlaminar non-fusion, tungsten inclusion while striking arc and shrinkage cavity while arc sup-pression. So that, the welding quality is effectively improved.Key words:austenitic stainless steel; intergranular corrosion; dangero

18、us temperature zone; welding linear energy(51 Failure Analysis of Furnace Tube Joint in Thermal Recovery BoilerYUE Feng (SINOPEC Shengli Oilfield Gudao Petroleum Production Plant, Dongying 257231, China , HE Yan-ling , HE Chang , et al.Abstract:Several furnace tube joints in a thermal recovery boile

19、r failed shortly after being put into use. Failure analysis was carried out using microscopy, SEM and chemical composition analysis instrument together with testing the distribution of hardness in welded joints. The results show that there are overlaps on back bead and overheated structure such as W

20、idmanstaten structure in the zone near the weld, and cracks propagate a-long the fusion zone or overheated zone. The distribution of hardness across backing bead is non -uniform comparing with that across other beads. Therefore, it can be concluded that it is the too big heat input applied to the ba

21、ck bead that induces the failure of the tube joints.Key words thermal recovery boiler; furnace tube; welded joint; failure analysis INSPECTION &DETECTION 53 Applying Ground Penetrating Radar to Detect Concrete Lining Quality in Tunnel Engineering HAN Gui -wu (China Petroleum Pipeline Engineering Corporation , Langfang 065000, China , CHENG Meng-peng , SU Wei-feng , et al.Abstract:This paper introduces the radar wave transmission and its reflection coefficient, dielectric con-stants of frequently used materials and working principle of ground penetrating radar (GPR, and describes the