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我公司承制的某车型行走系统油气悬挂装置中的活塞采用的是45号钢与铝青铜QAl9-2焊接而成,活塞是该系统的重要组成部分,其产品精度和质量要求高,该件为焊后加工而成,加工余量较小,焊接质量要求很高,必须一次施焊完成,没有返修余地,由于铜和钢两种金属的焊接属于异种金属焊接,焊接性较差,焊接难度大。主要问题在于铜与钢的熔点、导热系数、线膨胀系数和力学性能等都有很大的不同,容易在焊接接头中产生应力集中,导致各种焊接裂纹,焊接接头力学性能减低等焊接缺陷和焊道塌陷,气孔等其他常见缺陷。故而必须选择合适的焊接方法来保证一次焊接到位。
Pistons used in the oil-gas suspension system of a vehicle running system of a certain vehicle type made by our company are made of 45 steel and aluminum bronze QAl9-2. The piston is an important part of the system, and the precision and quality of the product are high. For the post-processing, the processing margin smaller, high quality welding, welding must be completed once, there is no room for rework, as the two kinds of copper and steel metal welding is dissimilar metal welding, poor weldability, welding difficulty Big. The main problem is that copper and steel melting point, thermal conductivity, coefficient of linear expansion and mechanical properties are very different, easy to produce stress concentration in the welded joints, resulting in a variety of welding cracks, weld joint mechanical properties such as reduced welding defects and Weld collapse, porosity and other common defects. Therefore, we must choose the right welding method to ensure a welding in place.