海洋工程用EQ56、EQ70钢埋弧焊与激光填丝焊焊接工艺研究

发布时间：2018-03-18 14:36

本文选题：低温冲击韧性　切入点：埋弧焊　出处：《江苏科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文依照海洋工程用EQ56、EQ70钢其合金成分和使用性能的要求,采用伊萨、奥林康、大西洋公司所生产的三种不同合金成分的埋弧焊焊丝和焊剂,进行了焊接材料熔敷金属的焊接试验,测试并分析了熔敷金属的力学性能,同时采用三种焊接材料对EQ56、EQ70钢进行了埋弧焊焊接工艺试验。研究了在相同热输入条件下,不同焊接材料对焊接接头的微观组织、力学性能的影响,以及在相同焊接材料下,不同热输入对其焊接接头的微观组织、力学性能的影响。同时,采用窄间隙激光填丝焊的方法对EQ70钢进行焊接,焊后对比分析了不同焊接方法对接头不同部位的微观组织和力学性能的影响。试验结果表明:采用三种埋弧焊焊接材料所得到的熔敷金属具均有良好的力学性能。EQ56钢埋弧焊采用伊萨OK Flux 10.62焊剂匹配OK Autrod 13.40焊丝,在焊接电压30V,焊接电流640A,层间温度160℃的焊接工艺条件下,得到的埋弧焊焊接接头具有优良的性能,柱状晶的晶粒较小且宽度较窄,内部分布着大量细小的针状铁素体。接头的抗拉强度为726MPa,-40℃条件下其焊缝中心的冲击功为117J,熔合区的冲击功为59J,熔合线+2mm的冲击功为62J,熔合线+5mm的冲击功为64J。EQ70钢埋弧焊采用伊萨OK Flux 10.62焊剂配合OKTubrod15.27S型焊丝,在焊接电压35V,焊接电流680A,层间温度170℃焊接工艺条件下,焊缝均含有大量的针状铁素体,少量的粒状贝氏体,极少数无碳贝氏体,得到的接头性能最优。抗拉强度为837MPa,-40℃条件下其焊缝中心的冲击功为91J,熔合区的冲击功为50J,熔合线+2mm的冲击功为62J,熔合线+5mm的冲击功为170J。在相同的焊材下,随着焊接热输入从30KJ/cm增大到40KJ/cm,EQ56、EQ70钢埋弧焊焊接接头都出现抗拉强度下降,低温冲击韧性下降的现象。HAZ区出现软化问题不可避免,要严格限制焊接热输入。对于EQ70钢,采用CARBOFIL FK 800焊丝的窄间隙激光填丝焊,单面焊双面成形良好而且变形量很小,焊缝均匀对称且没有发现侧壁未熔合、冷裂纹等缺陷,HAZ区很窄,仅为2mm左右。焊接接头的强度很高但焊缝中心的冲击功值很低,仅为45J,而熔合线+1mm区域的冲击功也较低,仅为50J。从整体分布来看,EQ70钢的埋弧焊接头的各区域硬度值普遍低于窄间隙激光填丝焊接头,但HAZ区的冲击功平均值要高于窄间隙激光填丝焊接头HAZ区冲击功平均值。
[Abstract]:According to the marine engineering EQ56, composition and performance of EQ70 steel the alloy, by Issa, Olin Kang, three different alloy compositions Atlantic Company produced by submerged arc welding wire and flux for the welding of welding material deposited metal, mechanical properties test and analysis of the deposited metal, at the same time using three kinds of welding material for EQ56 steel, EQ70 welding process test was carried out. The submerged arc welding is studied in the same heat input conditions on Microstructure of welded joint with different welding materials, mechanical properties, and in the same welding materials under different heat input welding joints on the microstructure, mechanical properties at the same time, using the method of narrow gap laser welding with filler wire is used for welding EQ70 steel after welding, comparative analysis of different welding methods on the microstructure and mechanical properties of joints in different parts of the impact test results. Show that the three kinds of submerged arc welding materials are deposited metal with mechanical properties of.EQ56 steel have good by Issa OK Flux 10.62 OK Autrod 13.40 flux matching wire submerged arc welding, the welding voltage 30V, welding current of 640A welding interlayer temperature of 160 DEG C, the submerged arc welding has excellent the performance of welded joints, the columnar grain is smaller and narrower width, the internal distribution of acicular ferrite fine ferrite. The tensile strength is 726MPa, -40 C under the condition of the weld center the impact energy is 117J, the fusion zone of the impact energy is 59J, the fusion line +2mm impact energy is 62J, fusion line +5mm the impact energy is by Issa 64J.EQ70 Flux 10.62 OK steel submerged arc welding with flux OKTubrod15.27S welding wire, welding voltage 35V, welding current 680A, interlayer temperature of 170 DEG C welding conditions, acicular ferrite containing large amount of weld Body, a small amount of granular bainite, a handful of carbon free bainite, the joint optimal performance is obtained. The tensile strength of 837MPa, -40 C under the condition of the weld center the impact energy is 91J, the fusion zone of the impact energy is 50J, the fusion line +2mm impact energy is 62J, the fusion line +5mm impact work 170J. under the same welding, as welding heat input increased from 30KJ/cm to 40KJ/cm, EQ56, welding joint are decreasing the tensile strength of EQ70 steel submerged arc welding, low temperature impact toughness decreased the phenomenon of.HAZ zone softening is inevitable, to strictly limit the welding heat input. For the EQ70 steel, using CARBOFIL FK 800 wire narrow gap laser the wire filling welding, one side welding and good welding deformation is very small, and there was a symmetrical side wall of the lack of fusion defects such as cold crack, HAZ zone is very narrow, only about 2mm. The strength of welded joints is very high but the impact toughness of welded seam The value is very low, only 45J, and the +1mm fusion line area of impact energy is low, only 50J. from the overall distribution, the microhardness of joint submerged arc welding of EQ70 steel is lower than the value of narrow gap laser welding with filler wire, but HAZ impact energy is higher than average value of narrow gap laser wire the welding head impact area HAZ power mean value.

【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG457.11

【参考文献】