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1.
The weld nugget formation in the resistance spot welding(RSW) of aluminum alloy was investigated in the present study. The nugget formation process was directly observed by using a digital high-speed camera. Numerical simulation was also employed to investigate the nugget formation process. The results showed that for the RSW of two aluminum alloy sheets, a nugget was first formed in the workpiece/workpiece(W/W) interface and grew along the radial direction and axial direction of the sheets, and then it became a large elliptical nugget. For the RSW of three aluminum alloy sheets, two small nuggets were firstly formed in two W/W interfaces and grew along the axial direction and radial direction; finally they fused into one nugget. Besides, there existed a critical welding time, after which the nugget size remained nearly unchanged. This indicates that a long welding time is unnecessary for the RSW of aluminum alloy. In addition, the calculated nugget radius was compared with the experimental results, which showed that the simulation results agreed well with the experimental results. 相似文献
2.
Spot welding was widely applied inindustries such asaviation, automobile , and other production departments .Aluminumstructures gradually take a prominent positionowingto lightweight and high intensity. But in quality in-spectionof aluminumalloys ,a single electrical parameter orthermal parameters[1]cannot effectivelyforecast the diame-ter of the weld nugget ,the intensity of spot weld, andsplashing duetotheinstabilityof weldzone caused byalloycompositions and fragile surface oxidation. Theref… 相似文献
3.
In this paper,the sensors array technique is applied to the quality detection of aluminum alloy spot welding.The sensors array has three forms,i.e.,linear magnetic sensors array,annular magnetic sensors array and cross magnetic sensors array.An algorithm based on principal component analysis is proposed to extract the signal eigenvalues.The three types of magnetic sensors array are used in the experiment of monitoring the signal.After the eigenvalues are extracted,they are used to build a relationship with ... 相似文献
4.
采用MULTISPOT MI-100电阻焊机,对车身用6061-T6铝合金薄板实施电阻点焊,研究并得到电阻点焊最佳工艺参数。然后,运用正交试验方案和极差分析方法对电阻焊工艺参数进行试验和进一步优化设计。在对2mm厚度的6061-T6铝合金薄板进行搭接电阻点焊后,分析焊接外观并完成拉伸测试,测试结果表明:当焊接电流60KA、焊接压力0.63MPa、板材厚度2.00mm时,试样所获得的点焊接头无明显缺陷,成型较好,具有良好的焊接质量和外观,其抗拉剪力值最大为5.583KN。 相似文献
5.
当前我国民族教育德育研究主要围绕民族团结教育、传统文化与德育、家庭道德教育、德育资源开发、留守儿童教育、民族宗教对德育影响、民族教育德育理论、学生思想品德、心理健康、未成年人犯罪、民族认同等前沿与热点问题展开研究。反思研究现状,展望未来研究的关注点,对推动我国民族教育德育研究,进一步深化民族教育改革,不断提高教育教学质量,为少数民族地区社会发展和经济建设培养合格的有用之才有积极意义。 相似文献
6.
对7075铝合金模型采用ANSYS有限元软件划分单元,利用函数功能实现热源移动的计算;并对该合金TIG焊接的热过程进行了计算机数值模拟的可行性研究。结果表明,焊接时温度场的分布呈现出一定的温度梯度,且以焊缝为中心对称。 相似文献
7.
Ni Jiansen Wan Xiaojing Wang Qing Cheng Xiaoying Liu Weimin Zhang Xingyao 《上海大学学报(英文版)》1997,1(1):79-82
The cyclic oxidation behaviors of Fe-28Al-5Cr-O. 1Zr (at%) and Fe-28A15Cr-O. 5Nb (at%) alloys have been investigated in air
at high temperature. The results show that the distinctive whisker-like oxides were formed on the surface of Zr-containing
Fe3 Al based alloy after 500 hrs. cyclic oxidation at 800 °C and 1000 °C. The results also indicate that the addition of small
amount of Zr to Fe3 Al based alloy can improve its adherence strength between the oxides and metal substrate and is beneficial to the oxidation
resistance. However, for the Nb-containing Fe3 Al based alloy, porous convoluted oxides were formed after 350 hrs. cyclic oxidation at 1000°C, and this type of oxides didn’t
not contribute to the oxidation resistance. 相似文献
8.
Simulation on Dynamic Characteristic of Negative Resistance Arc in Pulsed TIG Welding 总被引：1，自引：0，他引：1
The current waveform that can be modified inpulsed TIG welding results in such advantages as lowheat input and accurate control of the arc energy dis-tribution, which is in favor of obtaining high qualitywelding seam and easy to execute all-position weldi… 相似文献
9.
焊接是工程制造领域广泛使用的一种高效构件成型制造技术,但焊接过程中因焊接局部加热而形成的残余应力和变形是在工程制造中不希望出现的。焊接数值模拟能较为准确预测焊接构件中的焊接残余应力和变形的分布情况,可用以指导制造过程中焊接工艺参数的优化和焊接顺序的选择,为降低试验成本和缩短产品制造周期提供了一种可行的方法。对MSC.Marc软件焊接模拟热源模型、材料模型以及其在焊接残余应力和变形模拟中的应用情况作了介绍。 相似文献
10.
Laser shock processing (LSP), also known as laser peening, is a novel surface treatment technique in the past few years. Compressive
residual stresses which imparted by LSP are very important for improving fatigue, corrosion and wear resistance of metals.
Finite element analysis (FEA) simulation using ABAQUS software has been applied to predict residual stresses induced by LSP
on Ti-6Al-4V titanium alloy with laser pulse duration 30 ns and water confined ablation mode. The residual stress field generated
by different shape laser spots was studied, and the square laser spot is shown the most suitability for avoiding stress lack
phenomenon and overlapping LSP. Surface residual stresses and plastically affected depth within single square spot both increased
with the increase of laser intensity and laser shock times. Furthermore, compared with circle and ellipse spot, the residual
stress distribution in overlapping square spots is very uniform only with small overlapping ratio. LSP with square spot can
process advantageous residual stress field, and this technique will be used widely. 相似文献
11.
用ON、XRD、SEN、EDAX等对经不同制备工艺获得的AITiB和新型AITiBRE中间合金细化剂进行了微观组织的观察分析比较。结果表明：地TiBRE中间合金中细化相主要为TiA13和TiB2，还存在着不稳定的（AITiRE）相；地TiBRE中间舍金中细化相质点的分布形态优于A13TiBRE中间合金；氟盐法所制备的地TiBRE中间合金中细化相的分布更为均匀弥散与细小，优于纯Ti粉颗粒法制备的地TiBRE中间合金的组织。 相似文献
12.
点焊气动伺服控制系统常用于轿车白车身的焊接。在焊接过程中,保持焊点压力稳定是提高焊接质量的关键因素之一。基于焊接试验平台上,研究了气动系统的控制模型,提出模糊-滑模控制策略。针对辨识所得的气动系统,运用模糊-滑模控制策略对气动系统进行了仿真,结果表明,模糊-滑模控制策略适用于汽车点焊气动系统。 相似文献
13.
刘海侠 《河北软件职业技术学院学报》2005,7(4):55-57
本文研究用激光表面处理使碳素钢表面合金化,从而提高普通碳素钢的耐蚀性,且研究表明随着焊缝中铬含量的增加,耐蚀性提高。研究还表明用较高的扫描速度和较大的激光功率可获得稳定的焊逢形状。 相似文献
14.
娄红涛 《广东职业技术师范学院学报》2014,(7):16-18
针对当前国内外无铅化趋势的要求,简单比较了多种锡系合金可焊镀层的优缺点,提出纯锡可焊镀层的研究方向,并开发出一种纯锡电镀的添加剂,最后从外观、可耐焊、润湿效果、加速氧化、端头拉力等方面,对Sn-Pb镀层和纯锡镀层进行了比较,发现纯锡镀层的各种性能均不弱于Sn-Pb镀层,部分性能还要优于Sn-Pb镀层.另外,本文对各种焊膏的性能也作了比较. 相似文献
15.
概述了铝合金几种先进的焊接方法:钨极氩弧焊、电子束焊、激光焊及搅拌摩擦焊。重点介绍了铝合金最有前途的固相连接方法——搅拌摩擦焊,并展望了铝合金搅拌摩擦焊的应用前景。指出搅拌摩擦焊是铝合金最好的连接工艺,应深入研究。 相似文献
16.
《天津大学学报(英文版)》2020,(4)
The eff ect of Zn interlayer on the microstructural evolution and mechanical behavior of dissimilar ultrasonic-spot-welded Al/Cu joints was investigated. The tensile lap shear strength in relation to welding energy was analyzed. The experimental results show that two intermetallic compounds, Cu_5Zn_8 and Al_2Cu, were generated at the interface of the ultrasonic-spotwelded Al/Cu joint with a Zn interlayer. The primary joining mechanisms of the joint included the intermetallic compound bonding and metallic bonding caused by solid shear plastic deformation. Meanwhile, with increasing welding energy, the plastic deformation of the material became more substantial. With increasing welding energy, the tensile lap shear strength of the joints fi rst increased and then decreased for the ultrasonic-spot-welded Al/Cu joints with and without Zn interlayers. Under the energy input of 700 J, the bearing load capacity of the ultrasonic-spot-welded Al/Cu joints with a Zn interlayer improved signifi cantly due to the observed intermetallic compound(Cu_5Zn_8). 相似文献
17.
16MnⅥ(HIC)锻钢为低合金高强度结构抗氢钢,焊接性能良好。针对冷高分罐在制造过程中易出现的突出问题,分析了其基体材料16MnⅥ(HIC)的焊接性,阐述了克服该材料在焊接过程中出现缺陷的工艺措施。试验结果表明,通过采取合理的焊接工艺,可保证该类材料的焊接性,并为窄间隙埋弧焊焊接高压重容提供依据。 相似文献
18.
采用激光填丝焊对Al-Li-Er铝合金进行焊接处理,研究激光功率、焊接速度和送丝速度对焊接接头显微组织与力学性能的影响。结果表明,当送丝速度为3 m/min和4 m/min时,Al-Li-Er合金焊接接头的焊缝面积都会随着激光功率和焊接速度的增大而逐渐减小;在相同激光功率和焊接速度时,送丝速度的增加会增大焊缝面积,且随着送丝速度的增加,激光焊接接头的上余高系数和下余高系数都呈现逐渐增加的趋势。Al-Li-Er合金适宜的激光焊接工艺参数为激光功率3 kW、焊接速度3 m/min、送丝速度2~3 m/min,此时焊接接头的室温拉伸性能与母材较为接近。 相似文献
19.
成守权 《顺德职业技术学院学报》2008,6(3):23-26
通过热重分析实验,研究了在高温空气气氛中覆盖在Al-Zn—Si合金表面的MgO引发剂对铝合金直接氧化生长过程的作用。结果表明：MgO能显著缩短Al-Zn—Si合金熔体直接氧化所需的孕育期及Al2O3／Al复合材料的生长时间。同时发现MgO有助于Al2O3／Al复合材料以光滑的方式进行氧化生长,形成细化胞状晶团,提高组织结构的均匀度和材料的致密度。促进Al2O3／Al复合材料生长的MgO覆盖最佳量为12mg／cm^2。 相似文献
20.
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