共查询到19条相似文献,搜索用时 328 毫秒
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针对U20Mn高强耐磨贝马复相钢轨因闪光焊质量不佳制约了其在重载线路上应用的问题,采用特制高频感应加热装置将试样装配在液压式压力机上,模拟气压焊加热和顶锻过程,在相同热输入和顶锻量、不同顶锻速度下进行塑性压力焊接试验,观察研究焊接界面交互结晶的冶金焊接行为特征及其断口特征形貌。结果表明,贝马复相钢轨钢在塑性加热条件下,顶锻量为5~7 mm,顶锻速度小于等于6 mm/s压力焊时,可实现冶金焊接;但随着顶锻速度的增加,焊缝金属交互结晶的晶粒越细小,与母体晶粒差异越大,其断口特征呈现的脆性断裂程度越大。 相似文献
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以牛驼子箐大桥高墩HRB400箍筋焊接施工为例,设计四因素三水平的L9(34)正交试验,对焊接电流、焊接时间、顶锻压力和轴心位移偏差4个参数对箍筋电阻对焊质量的影响进行研究,结果表明:4种因素对箍筋焊接质量的影响程度由大到小依次为:焊件端面的轴心位移偏差>焊接电流>顶锻压力>焊接时间;为了使焊接接头抗拉强度更接近于母材材质的,焊接电流应取190 A,焊接时间应取0.8 s,顶锻压力应取0.5 MPa或0.6 MPa,焊件端面的轴心位移偏差越小越好;在对焊接工艺参数优化之后,大桥高墩箍筋的焊接优良品率从74%提升至90%,施工效率和质量得到有效提升。 相似文献
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钢轨焊接的主要方法有闪光焊、气压焊、铝热焊和电弧焊.其中,闪光焊的焊接质量最好.其他几种焊接方法,或由于其焊接原理的缺陷,或由于在焊接过程中受外界因素影响较多,焊接质量相对较差. 相似文献
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在建立了45钢环形结构件连续驱动摩擦焊的二维热力耦合有限元模型的基础上,研究了焊接过程中的温度场与材料流动对飞边形成的影响规律.结果表明,在摩擦阶段,材料主要沿轴向流动,而径向流动基本上为0;在顶锻阶段,在大的轴向顶锻压力的挤压作用下,摩擦面边缘及其附近的材料主要沿径向向摩擦面外流动并形成飞边,且飞边的尺寸与弯曲程度随焊接时间的增加而增加.同时,增加旋转频率以及轴向顶锻压力会导致飞边尺寸与弯曲程度的增加;基于飞边形貌给出了45钢环节结构件连续驱动摩擦焊的合理焊接工艺参数. 相似文献
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UN5—250型带钢闪光对接焊机,系为原6801工程配套的关键设备,由上海电焊机厂组织力量设计研制。在试验和调试过程中,气压、液压、传动系统以及初速度,烧化顶锻速度的调整机构动作均正常。对不同规格的带钢进行焊接试验表明,焊件极限强 相似文献
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UNS S 32205 duplex stainless steel specimens were joined by continuous drive friction welding process. The experiments were conducted as per the Taguchi(L16 orthogonal array) method. The friction welding process parameters such as heating pressure, heating time, upsetting pressure, upsetting time, and speed of rotation were fixed with low,medium, and high levels of range based on the machine capacity, and the required knowledge was acquired from the preliminary experiments. The joint characterization studies included micro structural examination and evaluation of mechanical properties of the joints. Microhardness variation, impact toughness, and tensile strength of the joints were evaluated. Neither a crack nor an incomplete bonding zone was observed. The tensile strength of the joints was higher than the strength of the base material, and the friction and upsetting pressures were found to influence the joint strength. The tensile strength of all the welds was observed to be increasing with an increase in the rotational speed. The toughness of the friction welds was evaluated at room temperature and also at subzero(cryo) temperature conditions. The toughness for friction welds was found to be superior to the fusion welds of duplex stainless steel at room temperature and cryo conditions. Weldments exhibited better corrosion resistance than the parent material. 相似文献
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以包钢U75V热处理钢轨焊接为对象,依据焊接接头型式检验结果,对比研究兰州铁路局中海拔地区基地闪光焊、现场移动式闪光焊、移动式气压焊及铝热焊接头性能。结果表明:基地焊接接头综合性能最佳,现场移动式闪光焊和移动式气压焊接头综合性能相近,铝热焊接头性能最差。 相似文献
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Z. Mikno 《Welding International》2005,19(11):845-849
Resistance welding is a process in which the main source of heat is the electric current flowing through the welding region. The result of the flow of current is the resistance heating of the area of contact between the elements to be welded. This results in either strong plasticisation or liquidity. If the upsetting pressure, exerted both during the flow of current and afterwards, is sufficiently high, a permanent joint between the welded elements will be made.7 The magnitude of the pressure should be sufficient to allow the flow of a high current of, possibly, several thousand amperes. Although the process of resistance welding has been known for over 125 years, it is still being improved. 相似文献
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转向架构架是高速动车组(electric multiple units, EMU)的重要承载部件,其侧梁的焊接质量直接关系到列车运行的平顺性及安全性. 为了研究焊接热输入对转向架侧梁焊接变形的影响,在侧梁结构中提取了曲线T形接头模型,以熔化极气体保护电弧焊(gas metal arc welding, GMAW)的焊接速度、焊接电流和焊接电压为研究对象,基于热机耦合仿真分析方法和具有交互作用的正交试验设计(design of experimental, DOE)方法建立代理模型,采用粒子群优化算法(particle swarm optimization, PSO)获得了最优的焊接工艺参数组合. 在此基础上,基于极差分析和方差分析(analysis of variance, ANOVA),进一步讨论了上述工艺参数对焊接热输入和焊接残余变形的影响. 结果表明,采用最优工艺参数的曲线T形接头模型焊接角变形比采用原生产工艺参数的结果降低了5.04%,采用最优工艺参数的侧梁模型可以保证上下盖板焊接残余变形满足平面度不大于1 mm的要求,无需焊后调平. 相似文献
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分析铝镁合金的焊接特性和变极性等离子弧焊的焊接特点及氩-氦电弧的特性,依据8~12 mm板厚5083的焊接经验,选用变极性等离子弧焊,分别采用氩气、氩气+氦气作为保护气体,对16 mm厚的5083铝合金进行焊接试验,通过优化焊接工艺参数,获得良好的焊缝成形;按JB/T 4730《承压设备无损检测》的要求对获得的焊接接头进行射线检测和渗透检测,通过机械性能试验验证焊接接头的机械性能,各项检测及试验结果均符合NB/T 47014《承压设备焊接工艺评定》的要求,获得的焊接工艺规范参数在高压封闭电器外壳筒体的焊接中稳定应用。 相似文献
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本文结合实际镦粗变形工艺,把镦粗变形划分为三个阶段或状态,即锻透、压实、焊合;指出空调压实后的形态或痕迹与空洞的形状,大小,空洞与主拉形变的方向有关,坯料镦粗时仅仅考虑整体锻比是不够的,还必须注意单次压下量,并介绍了一种既能压实焊合空洞类缺陷,又能改善夹杂物分布的新型V型板镦粗工艺。 相似文献