电极压力对三层超厚高强钢板电阻点焊质量的影响分析

以2 mm热成形钢板、2 mm冷轧双相钢板和3 mm微合金钢板,共3层钢板的电阻点焊为研究对象,获得了超厚钢板电阻点焊不同电极压力下的工艺窗口,确定了适用于超厚板电阻点焊的工艺参数。结果表明:随着电极力的增加,工艺窗口中的焊接电流宽度逐渐增大。考虑电极力及焊接时间,电极压力为4.6 k N,焊接时间为2×700 ms适用于3层超厚高强钢板的点焊。以前纵梁零件超厚板的电阻点焊为对象,适当增大电极压力和焊接电流,解决了因零件之间的间隙导致的气孔及表面毛刺缺陷。     

工艺参数对镀铝锌钢板点焊接头质量与组织的研究

通过镀铝锌钢板点焊实验,对十二组不同工艺参数下获得的点焊接头进行抗剪力实验和金相分析,研究表明:当采用较小的焊接电流和较短的焊接时间,接头熔合不良;焊接电流太大,焊接过程中飞溅很大,焊点表面压痕深度超标,同时形成方向性很强的粗大柱状晶;适当增加电极压力,可使柱状晶发生倾斜,方向性减弱.研究确定了0.8mm厚镀铝锌钢板较...     

轨道车辆碳钢点焊正交试验及分析

采用正交试验法对Q345D碳钢电阻点焊进行参数优化实验分析。通过对点焊强度影响较大的点焊参数(焊接电流、焊接时间和电极压力)进行单因素分析,得到焊接参数对点焊拉伸强度的影响规律,获得点焊参数的工艺窗口。在单因素分析基础上确定三因素三水平正交试验参数进行点焊实验,以点焊拉伸强度为评价指标对正交试验结果进行极差和方差分析,得到Q345D点焊的最佳工艺参数:焊接时间25CYC,焊接电流12 k A,电极压力9 kN。     

镀锡铜片电阻点焊工艺参数优化

为了优化镀锡铜片的电阻点焊工艺,采用正交试验法对表面镀锡3μm,尺寸为27 mm×11 mm×0.3 mm的无氧铜片进行电阻点焊试验研究和理论分析,研究了焊接参数对点焊接头的焊点直径和力学性能的影响,采用极差分析法分析了预热电流、预热时间、焊接电流、焊接时间、电极压力及保压时间等参数对镀锡铜片电阻点焊工艺的影响,并获得了其最优试验参数组合。研究结果表明:6个焊接工艺参数中,对焊点直径影响较大的是焊接电流和焊接时间,其它因素影响都相对较小;对剪切力影响最大的也是焊接时间与焊接电流,次要因素为保压时间与电极压力,预热电流与预热时间的影响最小。由试验结论可知,优化后的焊接工艺参数组合为:预热电流1200 A,焊接电流2600 A,预热时间25 ms,焊接时间12 ms,电极压力78.4 N,保压时间50 ms,此时能够获得外观成型良好,强度较高的焊点。     

基于LPSO与BP神经网络电阻点焊工艺参数建模优化

电阻点焊工艺参数的设置对点焊焊接质量有着非常重要的作用,难以建立精确的数学模型。基于此,提出一种将Logistic映射微粒群优化算法(LPSO)与BP神经网络相结合的方法,对0.8mm厚08AL钢板点焊工艺参数建模优化。在详细分析点焊工艺的基础上,利用BP神经网络建立点焊工艺参数与焊接质量之间的模型,同时结合LPSO的全局寻优能力,对点焊工艺参数进行优化,获得三大主要工艺参数(点焊时间、点焊电流与电极压力)的最优匹配。以点焊时间9周波、点焊电流11.41k N、电极压力1.7k N的最优工艺参数组合进行试验,结果表明,与BP+COA和正交实验法相比,该方法具有更高的可靠性。     

00Cr18Ni10N不锈钢点焊工艺参数的正交优化

应用正交试验方法对00Cr18Ni10N不锈钢电阻点焊工艺参数进行优化,确定了其点焊工艺参数的合理规范带为:焊接电流5800-6300A,电极压力5.1～6.0kN,焊接时间6～9cyc.研究发现,焊接时间对点焊接头单点抗剪力影响最显著,焊接电流和电极压力次之.     

热镀锌双相钢与普通热镀锌钢点焊工艺对比

用单因素法对比试验了两种基板材料不同的热镀锌钢板的点焊工艺,研究焊接电流、焊接时间和电极压力三个主要工艺参数对点焊质量的影响.结果表明,80 kg级热镀锌双相钢点焊工艺参数比普通热镀锌钢窄很多,普通镀锌钢接头抗拉剪载荷只有双相钢的1/3～1/2;焊接电流和焊接时间对焊点的熔核直径和接头抗拉剪载荷影响很大,电极压力对接头抗拉剪载荷和熔核直径影响甚小,变化幅度仅在500～1 000 N和0.5 mm以内.数据分析表明,以熔核直径为判据优化焊接参数时,抗拉剪载荷波动较大,可能出现强度偏低的情况,为此提出了以抗拉剪载荷为判据进行参数优化的方法,得到0.8 mm厚普通热镀锌钢点焊参数范围:焊接电流10～12.5 kA,焊接时间16～23 cyc,电极压力1 430～3 570 N;1 mm厚80 kg级热镀锌双相钢点焊参数范围:焊接电流10.7～11.7 kA,焊接时间13～19 cyc,电极压力2 150～3 200 N.     

镀锌钢板电阻点焊的工艺参数优化

在单因素轮换法的基础上,采用正交试验设计方法,研究了电阻点焊DX51D+Z冷轧热镀锌钢板时,焊接电流、预压时间、电极压力、焊接时间、维持时间的优化匹配对焊点质量的影响权重.通过对焊点拉伸和剥离试验分析表明,5个焊接工艺参数对焊点质量影响最大的是点焊电流,其次分别是电极压力、点焊时间、预压时间,而维持时间是相对最弱的影响因子.合理的焊接工艺参数为:点焊电流11 180A、预压时间40周、电极压力0.25 MPa、点焊时间17周及维持时间9周,此时能够获得外观成形良好、强度较高的焊点.     

不等厚异种铝合金电阻点焊的工艺分析

采用三相次级整流电阻点焊机,对不等厚度异种铝合金2A16(1mm)+2870(2mm)进行点焊试验,并选取焊点试片制备金相进行光学组织分析及做抗拉强度试验.通过改变电板结构和焊接参数(电极压力、焊接电流、焊接时间),确定了合理的工艺方案,试验结果表明:使用a种电极(有圆弧过渡的雏台形电极),在电极压力4kN,焊接电流3...     

焊接参数变化对低碳钢点焊接头剪切性能的影响

针对低碳钢的电阻点焊工艺进行研究,以焊后接头熔核的直径和抗剪强度作为性能评价指标,通过改变焊接电流和电极压力来优化焊接工艺,进而优化出1组较佳的工艺参数。结果表明:当焊接电流为1.08×104 A,焊接时间为0.5 s,电极压力为2 200 N时,可获得点焊接头较优的力学性能,点焊接头的抗剪强度达483.5 MPa,焊件熔核的显微组织为珠光体,呈柱状晶组织。     

热镀锌钢板连续点焊时电极损耗对焊接质量的影响

镀锌钢板电阻点焊时由于锌层的影响电极损耗非常严重。以厚0.8mm家电用热镀纯锌钢板DX51D+Z为研究对象,探究在正交试验优化焊接参数后,热镀锌钢连续点焊时焊接接头质量变化的规律和电极损耗的特点。结果表明,当采用I=11 kA、P=2 500 N、T=13 cyc的点焊工艺参数组合可获得力学性能最佳的点焊接头;连续点焊试验初期(150点前)焊点力学强度稳定且焊点成形较好,焊接后期(150～300点)接头力学强度波动大,焊接状况不稳定;电极损耗至失效是接头质量急剧下降的主要原因,电极失效形式为头部塑性变形、端面坑蚀和Cu-Zn合金化,在本试验条件下,Cr-Zr-Cu电极焊至150点后显现不稳定现象,电极寿命约280点;失效电极端面的Cu-Zn合金层约65μm。     

镀锌钢板电阻点焊的多元非线性回归模型

为了研究用于家用轿车车身制造的镀锌钢板电阻点焊工艺,采用多元非线性回归正交组合的方法设计试验.试验将电阻点焊熔核形状参数和焊接接头抗剪强度作为考察指标,将焊接电流、电极压力、通电时间、预热电流四个参数,以及各参数之间的交互作用作为影响指标的考察因素,得到可预测熔核形状和焊接接头力学性能的四元二次回归数学模型,并通过方差分析对模型进行优化.结果表明,优化的回归数学模型可实现焊接接头熔核成形及力学性能较为准确的预测.在模型的基础上研究各参数及各交互作用对焊点质量的影响规律,从而可实现电阻点焊工艺参数的优化设计.     

Gas hollow tungsten arc welding experiments in aircraft‐borne simulated space environment

The resistance spot welding process is widely used in the automotive industry, because it provides high productivity (over 20 spots per minute) and good quality. However, the introduction of galvanized steels onto production lines has brought difficulties in correctly adjusting welding parameters. This work therefore presents a detailed study of the influence of the principal parameters of the process (upslope time, current time, downslope time, electrode force and water flow) on the geometry and resistance of spot welds on galvanized steel plates. To do this, experimental robust planning was considered (the Taguchi method) for the factors mentioned above, evaluating the robustness of the system (analysis of the reduction of the signal/noise level) in regard to the diameter, indentation and mechanical resistance of the spot weld (responses). The difference between this work and others lies in the fact that instead of maintaining a fixed current level, which is the traditional method, the energy used in the process (current × time) is fixed. The conclusion is that it is possible to obtain robust parameters for a system in which the statistically significant parameter is current time.     

基于嵌入式系统的电阻点焊飞溅信息在线判读

钢材的电阻点焊过程中,动态电阻的变化表征了丰富的焊接质量信息.采用嵌入式系统实时监测焊接过程动态电阻的变化有利于提高对焊接质量的认识.设计了嵌入式监测系统,系统同时监测焊接电流、电极间压力和电极间的电压、电极位移信号.分析了双相钢DP600焊接过程中的动态电阻变化与焊点熔核之间的关系,并阐明用焊点两端的电压信号替代动态...     

The effect of process parameter on the properties of spot welded cold deformed AISI304 grade austenitic stainless steel

The electrode force, weld current, and weld time are three essential parameters of the resistance spot welding process. This paper deals with the characterization and understanding the effect of weld time and the influence of different weld atmospheres in the resistance spot weldability of AISI304 grade stainless steel deformed in tension by 5%, 10%, or 20%. Therefore, the microstructure of the weldment was evaluated and the hardness and tensile shear load bearing capacity of weldment were also determined. It was found that the final mechanical properties of weldment are directly related to the parameters of the process used, knowing the weld time and rate of deformation prior to welding.     

Ni在钢/铝电阻点焊中的作用

以DC01钢板与5082铝合金板为基材,在电极压力3 kN、焊接时间300 ms、保持时间100 ms条件下,研究了电阻点焊中焊接电流(9~12 kA)及Ni镀层对接头剪切力、正拉力、界面相组成的影响。结果表明,随焊接电流的提高,熔核尺寸增大,接头力学性能提高。剪切力比正拉力高一个数量级。在10 kA焊接电流下,镀Ni钢/铝接头的剪切力和正拉力均比钢/铝直接焊接时强度明显提高,这与钢/铝界面形成了Al 3Ni合金相,抑制了脆性Fe 2Al 5金属间化合物的生成有关。     

非等厚异种钢电阻点焊熔核成形的多元非线性回归模型

利用多元非线性回归正交组合的方法进行试验设计,分析两种厚度不一的异种钢板电阻点焊工艺.试验将表征非等厚异种钢材料电阻点焊熔核形状的熔核直径、熔核偏移,作为考察指标,将焊接脉冲电流、电极压力、焊接时间、热处理脉冲电流4个工艺参数,以及各参数之间的交互作用作为影响指标的因素,得到可预测熔核形状参数的回归数学模型.结果表明,优化的回归数学模型可实现该类非等厚异种钢电阻点焊接头熔核成形的较为有效的预测.在模型的基础上分析各工艺参数及各交互作用对焊点质量的影响规律,可进而对该类材料电阻点焊工艺参数进行优化设计.     

Non-destructive methodology for parameterization of Burn-Zinc in the resistance spot welding process

Galvanized steels are used in large quantities, mainly in the automotive industry, for their corrosion resistance and low cost. In this industrial sector, these materials are normally welded by the spot welding process. Because galvanized steels have a zinc-based covering layer, welding is normally carried out using a technique called the Burn-Zinc technique, to minimize the harmful effects of the zinc on this material, during the welding cycle. In this context, this work studied a non-destructive method, with the aim of finding suitable removal of this layer of zinc, on the basis of the signals generated by a sensor that records the electrode displacement during the phases of the spot welding process, taking the reading for the thermal expansion of the galvanized steel sheet as a basis. Thus, physical simulation experiments were undertaken, varying the current and the cycle time of the preheating phase. The Burn-Zinc responses generated by the sensor and the visual analyses by attribute were shown as graphs via an operating envelope. The evidence showed that the signal from electrode displacement proved to be an efficient non-destructive method for determining suitable Burn-Zinc parameters in the spot welding process for galvanized steel sheet.     

Investigation of Mechanical Properties of Galvanized Automotive Sheets Joined by Resistance Spot Welding

In this study, the electric resistance spot welding process was applied to zinc-coated steel sheets used in automotive industry. Spot welding parameters namely, electrode form, electrode material, and electrode force were stayed constant, and welding current and welding time have been changed to detect the optimum welding parameters for maximum joint strength. Using 4, 5, 6, 7, and 8 kA welding currents and 5, 10, 15, 20, and 25 cycles welding times 1.0-1.0 mm sheets were spot welded to prepare samples. These spot-welded joints were then exposed to uniaxial tensile test, and tensile-shear and tensile-peel forces prior to breaking were determined. In addition, microstructures were detected by SEM and micro-hardness was measured from different regions of resistance spot-welded samples and recommendations showing the optimum welding parameters were given to users.     

基于电极位移信号的电阻点焊质量预测模型

设计了电阻点焊过程动态参数监测系统，采集焊接电压、电流以及电极位移信号，建立以交流电阻点焊过程中的周波参数为输入空间，以试样的抗拉剪切强度为输出空间的点焊质量预测神经网络模型．为实现电阻点焊质量在线监控奠定了理论基础。试验结果证明了RBF神经网络用于这类应用场合的可行性和有效性。