铝合金/Q235镀锌钢板异种金属CMT焊接接头组织分析

采用ER4043铝硅焊丝和ER5083铝镁焊丝对5083铝合金与Q235镀锌钢板进行CMT焊接实验;通过对焊缝界面组织的SEM和EDS观察分析,研究不同焊丝对5083铝合金和Q235镀锌钢板异种金属焊接接头的影响。结果表明:采用ER4043铝硅焊丝得到的焊接接头性能比采用ER5083铝镁焊丝得到的焊接接头性能更优。     

Nb、Ti微合金化对Q345R压力容器板焊接性能的影响

 通过力学性能测试及微观组织分析研究了传统中板及低碳,Nb-Ti微合金化Q345R热连轧压力容器板在手工焊、气保焊及埋弧焊3种焊接工艺下的接头性能,测定了不同焊接工艺下接头各区域的硬度分布,评价了Q345R接头力学性能。试验结果表明,连轧Q345R板焊接接头具有更好的综合性能,其接头冲击韧性明显好于传统中板,粗晶区淬硬程度低。连轧板良好的性能来源于TMCP工艺下碳当量降低及Nb-Ti微合金化处理改善了基体及接头的微观组织。     

SPCC冷轧钢胶焊连接工艺研究及数值模拟

 为了研究胶焊工艺对接头力学性能的影响,并分析胶焊接头的温度场演变规律,针对1.5 mm厚的SPCC冷轧钢薄板,开展胶接点焊和电阻点焊的正交试验,并应用极差和方差分析得到最佳工艺参数,借助材料性能试验机对两种接头进行单向静拉伸试验获得接头的失效载荷,对比分析点焊和胶焊接头的力学性能,建立胶焊接头的仿真模型,分析接头熔核区温度场的演变规律,采用超声波C扫描成像检测熔核直径。结果表明,影响胶焊接头拉剪载荷的主、次因素依次为焊接电流、焊接时间、电极压力;胶焊接头和点焊接头的平均失效载荷分别为11 071.12和10 179.72 N,胶层的引入提高了接头的失效载荷;随着焊接时间的增加,熔融的金属液增多,熔核沿着径向和轴向呈椭圆形扩张,熔核中心的径向温度均高于轴向温度,模拟获得的熔核尺寸与超声C扫描测得熔核直径分别为6.17、5.61 mm。     

宽厚板Q345钢轧制工艺探讨

探讨了不同轧制工艺对Q345钢40、25、14 mm厚规格板组织性能的影响。结果表明:对于40mm和25 mm厚的Q345钢采用控制轧制方式,对于14 mm厚规格板采用任意轧制方式,均可得到较好的综合性能。不同板厚的钢板,由于冷却速度不同造成钢板越薄,韧性越差。     

1100 MPa级重型机械超高强吊臂钢焊接性能研究

通过Gleeble-3800试验机进行焊接过程热模拟,得出了Q1100D钢冷却过程中的CCT曲线。采用斜Y坡口焊接冷裂纹试验、金相分析和力学性能测试等方法,对不同热输入下焊接接头组织与性能进行了检测,结果表明包钢Q1100D重型机械超高强吊臂钢具有较好的抗冷裂性能。小热输入条件下可以实现室温下不预热焊接;较大热输入条件下,表面和断面未见冷裂纹,说明Q1100D钢板具有较好的抗冷裂性能。接头综合力学性能与组织性能评价结果表明,14 mm厚Q1100D钢板在1.05 kJ/mm的热输入下,焊接接头力学性能(拉伸、弯曲、冲击)处于最优状态。     

K-TIG焊接中厚板的工艺窗口改进

针对穿孔深熔氩弧焊(K-TIG)工艺焊接8 mm厚Q235低碳钢板时焊接过程不稳定、焊接工艺窗口小等突出问题,首次提出在焊接工件背部铺加保护焊剂的方法改善焊接过程。采用对接焊的方式,在不开坡口、焊接过程不添加焊丝的情况下,达到单面焊双面成形的效果。最终成功的采用430～480 A范围内的直流电流对8 mm厚的Q235低碳钢进行了焊接,将焊接电流窗口扩大到50 A同时也显著的提高了焊接过程的稳定性。同时,在扩大焊接电流窗口之后,系统研究了不同焊接电流下焊接接头的组织性能。研究结果表明:在不同焊接电流下得到的焊接接头中,组织分布以及力学性能分布呈现出相同的状态。焊缝区的组织均由铁素体+珠光体+魏氏组织组成;熔合区由魏氏组织组成;热影响区由铁素体+少量的珠光体组成;此外随着焊接电流的增加,焊接接头背部的熔宽有略微增加;在焊接接头中,熔合区处硬度值最高,其次是焊缝区,之后是热影响区,母材的硬度值最低;焊接接头最终的拉伸断裂位置是在热影响区处。      

莱钢200mm厚Q235B特厚钢板的开发

通过对300 mm厚连铸坯轧制200 mm厚Q235B特厚钢板的轧制道次分配方法、厚度控制、板形控制以及TMCP控轧控冷关键技术的研究攻关,成功开发出200 mm厚Q235B特厚规格产品,钢板厚度异板差控制在±1.2 mm以内,板形良好,附加检验1/4厚度0℃冲击功为86~91 J,1/2厚度0℃冲击功为55~77 J,Z向断面收缩率为27.0%~31.0%,较好地满足了高尺寸精度、良好低温冲击韧性和厚度方向性能要求。     

210mm厚度Q345R压力容器特厚板的研制

采用合理的成分和优化的工艺,开发出厚度为210 mm的Q345R压力容器特厚板,Q345R成分设计是在Q345碳钢的基础上添加适量微合金元素Nb、V、Ti,炼钢工艺采用铁水预处理脱S、LF+RH精炼,连续铸造成厚度为320 mm的坯料,通过2块320 mm坯料真空焊接,合理的加热温度、高温低速大压下控制轧制工艺、轧后堆垛缓冷、正火热处理等工艺,生产出力学性能优良、内部质量良好的Q345R特厚容器板。     

用Q235B坯料试轧制Q345B级别钢板的工艺分析

采用Q235B坯料在天钢3500mm轧机上试轧制Q345B级别钢板。通过对Q235B坯料进行轧制温度、变形量分配及轧后钢板快速冷却等控制,使其达到Q345B钢板力学性能的要求。试轧结果,12mm厚钢板力学性能除8#和9#钢板之外,其余钢板完全达到Q345B级钢板力学性能的要求;20mm厚钢板屈服强度和延伸率全部符合Q345B级钢板力学性能的要求,抗拉强度合格率为50％。分析了试轧工艺及实验结果,并针对20mm厚钢板提出了工艺改进方案,为今后再次试轧及大批量生产奠定了坚实的工艺基础。     

SAPH440酸洗板电阻点焊工艺研究

以2.0 mm厚SAPH440酸洗板为研究对象,通过检测点焊接头的抗剪性能及十字拉伸性能,综合评价接头的力学性能,并使用Axio Obersver A1m型光学显微镜观察点焊接头显微组织,测量熔核直径,分析焊接电流对熔核直径的影响,创建点焊工艺窗口。结果表明:酸洗板点焊工艺窗口为8.5 kA至12 kA,宽度3.5 kA,接头熔核直径及力学性能与焊接电流呈正相关,当出现飞溅后,熔核直径与力学性能略微下降,熔核区与热影响区组织均为马氏体,受焊接热循环的影响,熔核区组织为粗大柱状,热影响区组织为细小针状。     

Interface Behavior and Lap Shear Properties of the 7075-T6 Al FSLW Joint Using a Tip-Threaded Pin

For the purpose of reducing the hook and increasing the effective sheet thickness of the friction stir lap welding joint, a tip-threaded pin was used to weld 3 mm-thick 7075-T6 aluminum alloy in this work. Material flow behavior, joint formation mechanism and lap shear properties of the lap joints were mainly discussed. Results showed that when using the tip-threaded pin, lap joint with nearly aequilate stir zone (SZ) along thickness and rather flat hooks were obtained. When using high rotating speeds, the width of the lower SZ exceeded that of the middle SZ. A void, which resulted from the material loss near the lap interface, was observed at the same time. With increasing the rotating speed, the lap shear failure load of the joint initially increased and then decreased, while the fracture mode changed from tensile fracture to shear fracture mode. The maximum failure load of 17661 N was attained for the joint without void at 850 rpm.     

A Study of Thickness Effect on Fatigue in Thin Welded High Strength Steel Joints

It is well known that the fatigue strength of welded joints decreases when plate thickness increases. This decrease in fatigue strength is known as the thickness effect. In many standards for fatigue design the thickness effect is taken into account for joints with plate thickness typically greater than 25 mm. Previous work has mainly been focused on joints with plate thickness between 12‐200 mm. Less attention has been paid to thinner joints. Published investigations on joints with sheet thickness 2‐12 mm show an increase of fatigue strength with decreasing sheet thickness. In the present study results from constant amplitude fatigue testing of non‐load carrying welded joints in high strength steel of thickness 3‐12 mm are presented. The results show an increase in fatigue strength with decreasing sheet thickness down to 3 mm. Fracture mechanics calculations confirm the test results.     

焊接材料对双金属复合板焊接接头性能的影响

为研究焊接材料对Q235B/304双金属复合板焊后性能的影响,采用手工焊条电弧焊方法焊接 Q235B/304双金属复合板,焊接材料分别为THNi317焊条和THA062焊条。利用光学显微镜及EDS（X射线能谱仪）分析了焊接接头金相组织和合金元素在熔合线两侧的分布情况,并进行了焊接接头力学性能试验。结果表明,两种焊条的焊缝组织主要均为奥氏体γ和少量δ铁素体。THNi317焊接材料可以更加有效控制碳元素扩散以及铬和镍合金元素稀释。采用两种焊条获得的焊接接头抗拉强度和硬度均满足标准要求,但是采用THNi317焊条获得的焊缝和热影响区比采用THA062焊条获得的焊缝和热影响区具有更好的冲击韧性。     

国产SS41钢焊接性能研究

研究了国产ＳＳ４１普通碳素结构钢的焊接性能。通过与相同成分及板厚的Ｑ２３５钢试验对比试验：ＳＳ４１钢采用Ｅ４３１５低氢焊条（手工电弧焊）、Ｈ０８Ａ焊丝配ＨＪ４３１焊剂焊接，焊接接头的力学性能与Ｑ２３５钢相当，可以替代Ｑ２３５钢用于重要的焊接结构工程。     

Q235热轧钢板冷弯裂纹分析

对不同规格的Q2 3 5热轧钢板冷弯裂纹试样进行了金相检验和电子探针等分析。结果表明,厚度为1 0mm的Q2 3 5热轧钢板宽冷弯裂纹主要是由板厚1 /4处存在大量的硫化锰夹杂物和磷的强偏析带所引起的;厚度为1 2mm的Q2 3 5热轧钢板宽冷弯裂纹主要是因板面存在一定深度的凹坑及微裂纹缺陷所造成的。     

Effect of Operation Parameters on Diffusion Bonded AA5083, AA6082 and AA7075 Aluminum Alloys

Rolled plates of 5 mm thick AA5083, AA6082 and AA7075 aluminum alloys Joints were fabricated by diffusion bonding at different temperatures. The microstructure evolution of AA5083, AA6082 and AA7075 aluminium alloys were characterized by transmission electron microscopy. Metallurgical investigations and mechanical tests were also performed to correlate the microstructural investigations with the mechanical properties of the produced diffusion bonded joints. It was observed that the bonding and shear strength increased with the increase in bonding temperature due to the diffusion of micro-constituents in the interface. Higher temperature enhanced the uniform distribution of secondary phase particles, which further improved the reduction in pores/defects in the bonded joints.     

5083 H321铝合金板材制备组织性能研究

基于"1+4"热连轧生产线、2800mm冷轧生产线,采用不同工艺线路制备了5083 H321铝合金板材,研究了不同制备工艺对板材组织性能的影响.结果表明,不同工艺路线成品板材力学性能、耐腐蚀性能及微观组织均存在明显差异.采用"1+4"热连轧生产线短流程工艺制备的5083 H321铝合金板材性能:抗拉强度358MPa、屈...     

Optimization of friction stir spot welding process parameters of dissimilar Al 5083 and C 10100 joints using response surface methodology

Using response surface methodology, optimization of friction stir spot welding process parameters of dissimilar Al 5083 and C 10100 joints were experimented. The predominant requirement was to obtain reduced interface hardness and increased tensile shear failure load. For specification of experimental conditions, central composite design matrix was used, with three factors and five levels. With Al 5083 alloy and C 10100 copper twenty joints were made. Experimentally, tensile shear failure load and interface hardness were measured. Significant main parameters and interaction process parameters were evaluated using analysis of variance (ANOVA) method. Regression analysis was used for development of empirical relationship. Design expert software was used for optimization of friction stir spot welding process parameters by using response graphs and constructing contour plots. At 95% confidence level, prediction of tensile shear failure load and interface hardness of the dissimilar Al 5083—C 10100 joints were done using the empirical relations that were developed. The optimum conditions of Al 5083—C 10100 joints by friction stir spot welding process were evaluated using contour plots.     

鞍钢17Mn阻尼钢4 ~ 100 mm板的研制

鞍钢研制的 17Mn 阻尼钢(/% ：0.02C, 0.08Si, 17.53Mn, 0.014P, 0.002S, 0.005Als) 4 ~ 100 mm 板,其 屈服强度311 ~4O7 MPa,15~100 mm板-20°C. V型缺口冲击吸收能量113-144 J,焊接后焊接接头抗拉强度651 ~ 654 MPa,焊接后-20 °C V型缺口冲击吸收能量66~84JO 17Mn阻尼钢组织为残余奥氏体和e马氏体,使用动态机 械热分析仪检测其阻尼性能。在30 °C ,50 Hz双悬臂应变扫描条件下,不同厚度阻尼钢阻尼值均大于0.02;在100 Hz 下测试不同厚度阻尼钢阻尼值均大于0.05,阻尼值高于传统的低合金结构钢Q235、Q345(0.008和0.010 ~0.013)。