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近代航空发动机钣制件的连接,几乎全部采用了点焊和滚焊,而组成焊件的主材通常采用不锈钢和耐热钢,其中用得最广泛的有镍铬不锈钢1Х18Н9Т和镍铬耐热合金ЭН-435。1Х18Н9Т和ЭН-435均属于奥斯丁体类钢,它们具有较一般碳钢特殊的物理性能:高的电阻系数和线膨胀系数低的导热系数;从工程特性上来看,这两种材料在高温状态下能保持较高的强度(高温塑性差)。上述这些特性在ЭН-4S5上表现得尤其突出。由于材料的导热性不良,施焊时在焊缝附近呈现出巨大的温度梯度。介于核心附近的金属阻碍熔融金属的膨胀,当焊缝冷却时,由于残留应力的作用,很容易形成缩孔和裂纹。因此必须严格控制焊接参数,以保证焊缝附近在有限范围内达到最小的翘曲变形,并获得令人
Modern aviation engine sheet metal parts connection, almost all of the use of spot welding and seam welding, and the main components of the welding material is usually made of stainless steel and heat-resistant steel, the most widely used nickel-chromium stainless steel 1Х18Н9Т and nickel-chromium heat Alloys ЭН-435.1Х18Н9Т and ЭН-435 belong to Austenitic steels, which have special physical properties as compared with ordinary carbon steels: high resistivity and low coefficient of thermal conductivity; in terms of engineering characteristics, Both materials maintain high strength (high temperature plasticity) at high temperatures. These characteristics are particularly prominent on the ЭН-4S5. Due to the poor thermal conductivity of the material, the weld presents a huge temperature gradient near the weld. The metal near the core hinders the expansion of the molten metal, and when the weld cools, shrinkage holes and cracks are easily formed due to the residual stress. Therefore, the welding parameters must be strictly controlled so as to ensure the minimum warping deformation in a limited range near the weld and obtain satisfactory results