铁素体不锈钢激光-MAG复合热源焊缝成形及接头冲击韧性分析

利用激光-MAG 复合热源分别进行了 T4003 和 TCS 铁素体不锈钢的焊接试验研究.通过与常规 MAG 焊的对比,测试分析了两种焊接方法的焊缝成形、接头的低温冲击韧性及接头的微观组织.结果表明,激光-MAG 复合热源焊接易于实现铁素体不锈钢的单面焊双面成形,与常规 MAG 焊相比,其焊接效率可以提高 1 倍以上.利用激光电弧复合热源可以提高铁素体不锈钢焊接接头的低温冲击韧性,较常规 MAG 焊,复合焊接头的低温冲击韧性可以提高 50%以上.激光-MAG 复合热源焊接接头热影响区粗晶区组织宽度明显小于常规 MAG 焊接头的粗晶区宽度.

Abstract：

Laser-MAG hybrid welding of T4003 and TCS ferrite stainless steels was studied. Through comparing with the conventional MAG welding of ferrite stainless steel, the results of the two welding methods including the appearance of weld, impact toughness under low temperature and the microstructure of the butt joints were tested and analysed. The analysing results show that it is easy to get one-side welding with back by laser-MAG hybrid welding. Comparing with the conventional MAG welding, the welding efficiency of ferrite stainless steel by laser-MAG hybrid welding can be improved more than one times, the low temperature impact toughness of the joints by laser-MAG hybrid welding can be improved over 50% than that of conventional MAG welding joints, and the width of coarsegrained zone of hybrid welding joints is thinner than that of MAG welding joints.     

Laser-pulsed MIG hybrid welding technology of A6N01S aluminum alloy

Welding research of A6N01S-T5 aluminum alloy profile for high-speed train was done by using laser-MIG hybrid welding and MIG welding individually. And the weld appearance,welding distortion,mechanical properties of the joints and microstructures were analyzed. The test results demonstrated that high-efficient welding for the profile can be achieved by using laser-MIG hybrid welding,the speed of which can be over 3. 0 m/min. The processing had a good gap bridging ability,even if the gap of the butt joint was up to 2. 0 mm,a good weld appearance can also be got. While the hybrid welding speed was greater than 2. 5 m/min,the welding distortion of the laser-tandem MIG hybrid joints was just about 33% of that of the MIG joints,but the welding efficiency was over 3 times of MIG welding. And tensile strength of the hybrid joints was 85% of that of A6N01S-T5 base metal,9% higher than that of the MIG joints. Fatigue properties was tested individually with pulsed tensile fatigue method in the condition of 1 × 10~7 lifetime. The test results demonstrated that the fatigue strength of the joints was a little lower than that of base material,which could be up to 115 MPa. But the fatigue strength of hybrid welding joints was 107. 5 MPa,which was 23% higher than 87 MPa of MIG welding joints.     

Study of the Laser-MIG Hybrid Welded Al-Mg Alloy

The technology of laser-MIG hybrid welding is hotspot in welding researched field at present.It can improve the velocity of the welding,reduce the distortion of the welding,optimize the structure of the welding joint and etc..The 5052 aluminum alloy of the 10mm thick was welded by the laser-MIG hybrid welding.The structure,the alloy elements profile and the mechanical property of the welded joint are researched by the optical microscope,SEM,sclerometer and etc..The results showed:The medium thick Al alloy was welded in high speed by the laser-MIG hybrid welding.The appearance of the welding joint is well.The weld joint and the weld interface are fine.The intenerate region in the welding joint is small.The tensile strength in welding joint has achieved 94.4% of that in base metal.     

Friction stir welding of copper alloys

Copper plates ,brass plates and copper/brass plates were friction stir welded with various parameters. Experimental results show that the microstructure of the weld is characterized by its much finer grains as contrasted with the coarse grains of parent materials and the heat-affected zones are very narrow. The microhardness of the copper weld is a little higher than that of parent plate. The microhardness of brass weld is about 25% higher than that of parent material. The tensile strength of copper joints increases with increasing welding speed in the test range. The range of parameters to obtain good welds for copper is much wider than that for brass. When different materials were welded, the position of copper plate before welding affected the quality of FSW joints. If the copperplate was put on the advancing side of weld, the good quality of weld could be got under proper parameters.     

Research on the properties of laser welded joints of aluminum killed cold rolled steel

Aluminum killed cold rolled steel used for automobiles was welded in this paper by using CO2 laser with wavelength 10.6μm.The experiment shows that high quality of welding can be realized at welding speed of 4500mm/min by optimizing the parameters.The strenth and hardness of laser welded joints for aluminum killed cold rolled steel increased compared to those of the base metal while the formability decreased.Forming limit diagram of joint material indicated that the laser weld seam should avoid the maximum deformation area of automobile parts during the designing period for the position of weld seam.     

Ti17合金惯性摩擦焊接头力学性能与组织分析

通过室温拉伸、高温拉伸试验以及金相分析对 Ti17 合金惯性摩擦焊接接头的显微组织和力学性能进行了研究.结果表明,采用惯性摩擦焊焊接 Ti17 合金可获得室温及高温性能良好的焊接接头,其焊接接头的室温及高温抗拉强度都不低于母材;Ti17合金母材组织为α+β相,并且β相呈针状均匀分布在α相的基体上;不同焊接工艺参数对 Ti17 合金惯性摩擦焊接头热影响区和焊缝的组织没有影响,其热影响区组织为α+β相,并且β相呈针状均匀分布在α相的基体上,与母材组织相同,焊缝组织为细小的等轴晶.

Abstract：

The microstructures and properties of Ti17 alloy joints welded by inertia friction welding (IFW) were investigated by room-temperature tensile test, high-temperature tensile test and metallographic analyses. The results show that the joint with good performance at room and high temperature for Ti17 alloy can be obtained in IFW. Both the tensile strengths of welded joints at room temperature and at high temperamre are not less than those of the base metal. The microstructure of Ti17 alloy is α+β phase, and the needle β phase is distributing on the α phase. While welding, different welding parameters can not affect the microstructures of the HAZ and the weld seam. The microstructure of HAZ is the same as that of the base metal, and that of the welded seam is fine equiaxed crystal.     

激光辅助活性焊接法

提出了激光辅助活性焊接的方法,研究了焊接参数对激光熔化处理后TIG焊接熔深、熔宽的影响.首先,使用极小功率激光在氧气保护下熔化焊件表面,使焊缝表面的氧含量增加.然后使用普通的TIG焊接,覆盖激光焊缝,达到增加熔深的目的.利用此方法,不使用活性剂就可以使TIG焊焊接熔深增加约2倍,与A-TIG焊相比没有表面熔渣,表面成形较好.小功率激光处理后焊缝中O元素含量增加,熔池表面张力温度系数由负变正,导致激光辅助活性焊熔深增加.

Abstract：

On the bases of the study for the mechanism of the increasing of A-TIG welding penetration, a new method of activating TIG welding, the laser aided activating TIG welding was proposed. At first, the surface of weld was melt by the mini power laser protected by oxygen. As a result, the oxygen content increases in the weld pool surface. Then the conventional TIG welding was used to cover the weld. The oxygen could change the direction of fluid flow in molten pool, which leads to the weld beads with narrower width and deeper penetration. Without the activating flux, the penetration can be increased by 2 times. There is no slag in the surface of weld and the appearance is good. The oxygen can change the temperature dependence of surface tension gradient from a negative value to a positive value; and cause the significant changes in the weld penetration. Fluid flow could be inward along the surface of the weld pool toward the center and then down. This fluid flow pattem transfers heat to the weld root and produces a relatively deep and narrow weld efficiently. This change is the main cause to increase the penetration.     

Characteristics of 5A90 Aluminum-lithium Alloy by YAG-MIG Hybrid Welding

The characteristics of 5A90 Aluminum-Lithium alloy by YAG laser and MIG arc hybrid welding (Hybrid welding) were studied.Compared with the laser beam welding (LBW),the hybrid welding could not only improve the weld appearance significantly,but also have better engineering compatibility.The obvious microstructure characteristics of joint by the hybrid welding are fine-grained layer near fusion-line and the equiaxed grain in most area of welded seam.The subgrains of the equiaxed grains,located in the weld center,tend to coarse from bottom to top of weld joint.The microhardness of welded seam by the hybrid welding (83.57HV0.2) is lower than that by LBW (95.65HV0.2),but the uniformity of the former is better than that of the latter.The ultimate strength and the elongations after fracture of the joint by the hybrid welding are lower than that by LBW.The tensile fracture always occurs in HAZ or weld centerline,and the fractography presents mixture rupture.Therefore,if the combined mechanical properties of joint by the hybrid welding meet the operation requirements,it should be improved by reasonable artificial aging or heat treatment after welding,and it also should develop a better filler wire matched with the base metal.     

镀锌薄板TIG拼焊的焊缝组织及成形性能

采用钨极惰性气体焊对镀锌薄板 SGCC 实施等厚拼焊,测试分析了拼焊板焊接接头的金相组织、显微硬度,并对拼焊板和母材试样进行杯突试验.结果表明,在拼焊过程中,母材的散热情况不同会造成焊缝金相组织在靠近母材的局部区域有很大差异.焊缝熔合区组织为粗的片状与块状先共析铁素体沿柱状晶界分布,晶内为魏氏体组织和片状珠光体,热影响区为块状的珠光体和铁素体,导致了焊缝及其热影响区的硬度均高于母材,对拼焊板的整体成形性能产生负面影响;同时,焊缝杯突值较母材有一定程度的降低,揭示其焊缝深冲性能低于母材.

Abstract：

The microstructure and micro-hardness of welded joint of SGCC by tungsten inert-gas (TIG) welding are studied, and the cupping test of Tailor-welded blank and base metal are studied.The results show that in the welding process, the microstructure of weld will have great diversity at local region closing parent metal because of the different cooling condition of the parent metal. The microstructure of welding fusion zone is massive sheet proeutectoid ferrite distribution along the columnar grain boundaries, intragranular organizations are Widmanstatten and sheet pearlite structure, and the microstructure in HAZ is massive pearlite and ferrite, which make the micro-hardness value of welding seam and HAZ higher than that of base metal and lead negative influence to the formability of Tailorwelded blank. The cupping value of weld seam reduces to some extent compared with that of base metal, which indicates that the formability of weld seam is not good as that of base metal.     

镁合金MIG焊接工艺及焊接接头组织性能分析

采用脉冲 MIG 焊接工艺,进行 AZ31B 镁合金板材的焊接性分析,焊后利用光学显微镜、扫描电子显微镜、万能拉伸试验机和显微硬度仪等设备对焊接接头的组织与力学性能进行了检测分析.结果表明,通过优化工艺参数,采用脉冲 MIG 焊接工艺可以在不开坡口、不需背面强制成形的条件下,实现镁合金单面焊接双面成形,获得连续、没有表面缺陷的焊接接头.焊接接头的热影响区较窄,晶粒稍有长大.焊缝区组织均匀,晶粒细小,硬度值高于母材.焊接接头的抗拉强度可达到母材的 95% 以上.

Abstract：

The pulsed MIG welding was used to weld AZ31B Mg alloy, and the weldability of the alloy was studied. The microstructure, mechanical property and hardness of the welded joint were investigated via the metal phase microscopy, scanning electron microscope, tensile testing machine and hardness instrument. The results show that one-side welding with back can be obtained through this technique at optimized parameters when there was no groove and no shaped ban, which continuous butt joints have no surface defects.The heat-affected zone of the joints is narrow, and the grains of the zone are slightly larger than that of the base metal. The grains of fusion zone are tiny, the microstructure is homogeneous and the hardness of welded joint is higher than that of the base metal. The tensile strength is up to 95% of the base metal.     

活性剂对激光-电弧复合焊接的影响

提出了激光-电弧复合活性焊接法,以提高小功率激光-电弧复合焊接的熔深.在待焊不锈钢表面涂覆一层活性剂,然后进行激光-电弧复合焊接.研究了工艺参数对焊缝成形性的影响,并对焊接接头的组织性能进行了分析.结果表明,涂覆活性剂后可以使复合焊接的熔深增加,并且可以细化复合焊焊缝组织.复合焊接头与复合活性焊接头的显微硬度变化规律一致.复合活性焊接头的抗拉强度较高,达到母材抗拉强度的92%.复合活性焊接头的腐蚀速率低于复合焊接头的腐蚀速率,具有良好的耐蚀性能.     

高强铝合金的MIG以及激光-MIG焊接工艺对比

以20 mm厚的2519-T87高强铝合金为研究对象,研究了熔化极惰性气体保护焊 (MIG焊)和CO2激光-MIG复合焊的焊接效率、组织以及力学性能之间的区别.结果表明,激光-MIG复合焊的焊接效率是MIG焊的5倍,焊接熔深更大,接头的抗拉强度也提高到母材的70%以上,而MIG焊接头抗拉强度仅仅只有母材的60%左右.由于复合焊的热输入比较小,而且熔池的熔融金属的流动情况以及温度梯度与MIG焊有很大的不同,复合焊的焊缝组织比MIG焊的更加细小,接头处的也没有发现MIG焊接头中出现的等轴晶区.     

铝合金双光束/单光束激光-TIG复合焊

针对4mm厚5A06铝合金,分析了双光束光纤激光-TIG复合焊的焊缝成形特点、气孔率、匙孔动态特征及接头力学性能,并与单光束光纤激光-TIG复合焊对比。结果表明,在获得相同焊缝背面熔宽条件下,与单光束激光-TIG复合焊相比,双光束激光-TIG复合焊的焊缝背面成型连续性、均匀性更优且熔宽波动较小,焊缝气孔率降低50%以上,激光匙孔开口面积平均值更大,波动变异系数更小;双光束激光-TIG复合焊接头抗拉强度、断后伸长率、显微硬度、组织与单光束激光-TIG复合焊结果差别不大。     

Process and joint characterizations of laser-MIG hybrid welding of AZ31 magnesium alloy

High power laser-metal inert gas (MIG) hybrid welding of AZ31 Mg alloys was studied. Microstructure and fracture surface of welded joints were observed by optical microscope and scanning electron microscope. The mechanical properties of welded joints were evaluated by tensile test. Under the optimal welding parameters, the stable process and sound joints were obtained. The tensile strength efficiency of welded joints recovered 84-98% of the substrate. It was found that the arc was compressed and stabilized by the laser beam during the hybrid welding. The compressed extent of arc column increased with laser power, and the process stability could be improved by increasing laser power and arc current or slowing welding speed. The arc stabilized mechanism in laser-MIG hybrid welding of Mg alloys was summarized in two factors. First, the laser keyhole fixes the arc root and improves the igniting ability of the arc. Second, the electromagnetic force is downward and increased by the laser-arc interaction, which prevents the overheating of the droplet and smoothes droplet transfer from the wire to the weld pool.     

10Ni3CrMoV钢CO2激光多层焊的接头组织与性能

与传统电弧焊相比,激光焊接厚板优势明显。采用纯激光焊和激光电弧复合焊等多道焊接技术实现了28 mm厚10Ni3CrMoV钢的高效焊接,采用光学显微镜分析焊缝、热影响区和焊缝重叠区的组织,激光复合焊缝组织主要为针状铁素体,纯激光焊缝、粗晶区和细晶区组织主要为板条马氏体,激光复合焊缝重叠区组织为粒状贝氏体+马氏体,纯激光焊缝和激光复合焊缝重叠区组织为马氏体+少量粒状贝氏体。测试了焊接接头的力学性能,结果表明,激光复合焊缝金属的冲击韧性较高,焊接接头的抗拉强度和屈服强度与母材相当,延伸率略小于母材,焊接接头的最大硬度小于360 HV,弯曲性能合格。     

6N01S-T5铝合金高速激光-MIG复合焊接工艺

针对高速列车侧墙6N01S-T5铝合金熔化焊时存在焊接变形大,接头软化严重等问题,提高激光-MIG复合焊的焊接速度降低热输入,并通过显微硬度、拉伸试验测试,结合金相及扫描电镜下的EDS分析,对比了高、低焊接速度两种工艺下接头力学性能及微观组织的差异;采用三坐标测量仪和X射线残余应力测试仪对试样焊接变形和残余应力进行测试分析.结果表明,当焊接速度达到4.8 m/min时焊缝仍能保证较好的成形;相比于0.6 m/min低速焊接,焊接效率大幅度提高,焊缝金属填充量减少68%,接头软化区宽度减小约60%;试件焊后变形及高应力分布区域变窄;焊缝组织细密,接头平均抗拉强度为207 MPa,达到母材强度的71%.     

高速列车6N01侧墙激光复合焊接头软化行为分析

采用激光-电弧复合焊工艺焊接高速列车侧墙6N01铝合金型材,并对焊接接头的软化行为进行分析. 通过拉伸试验、显微硬度测试、微观金相试验和拉伸断口SEM试验,系统分析激光-电弧复合焊焊接接头软化行为,并与目前生产中应用的MIG焊接头的性能进行对比. 结果表明,采用复合焊,焊接接头强度均较MIG焊接头的强度提升10%以上,HAZ的软化区较MIG焊的减小了40%～60%;激光复合焊接头金相组织晶粒更细小,第二相质点数量多而且弥散细小,MIG焊热影响区晶粒长大倾向较大,强化相质点数量少并且尺寸较大. 采用激光-电弧复合焊方法对高速列车车体的侧墙所发生的焊接接头软化有较大的改善.     

双丝埋弧焊接头性能研究

在16Mn钢板上进行双丝自动埋弧焊工艺试验,得到了不同焊接速度下的焊件.对不同工艺参数下得到的焊接接头试样进行了拉伸试验、硬度测试以及金属显微组织观察,并计算了双丝自动埋弧焊时的熔敷率.结果表明:采用双丝埋弧焊得到的焊缝外形美观;金属熔敷率与焊接速度成反比;随着焊接速度的降低焊接线能量相应的增大,较长的高温停留时间会促...     

高强钢CO2激光-MAG复合焊接性能

为了研究CO₂激光-熔化极活性气体保护焊（MAG）复合焊接性能,采用CO₂激光和CO₂激光-MAG复合焊接590MPa级高强度钢,对其焊接接头的显微组织和力学性能进行了研究.结果表明,激光-MAG复合焊接的焊缝金属中,MAG电弧作用区主要为珠光体和贝氏体,激光作用区主要为马氏体;激光-MAG复合焊接的焊缝金属中Mo和Mn合金元素的分布具有不均匀性;激光和激光-MAG复合焊接的试件焊接接头拉伸性能完全满足要求,焊缝强度高于基体强度;激光-电弧复合焊缝金属在-60℃～+15℃试验温度范围内的冲击韧性比激光焊缝金属高;激光-MAG复合焊接焊缝金属硬度在250～400 HV之间,高于基体金属的硬度.