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铸铁的焊接特点铸铁有高的含碳量和含硅量,强度低,塑性差,膨胀系数较大,对加热和冷却有较高的敏感性,是属于可焊性差的材料。焊补中常出现裂纹、白口及气孔等弊病。一、产生裂纹的原因及其防止铸铁的强度较低,塑性差,因此在焊后冷却过程中,焊区的应力不断增加,当焊接应力超过铸铁的强度极限时,就突然断裂或焊缝与母材剥离,有时伴有“咔”的响声。裂纹也可能出现在焊缝附近,强度薄弱处或应力易集中的尖角处。裂纹方向是顺着焊缝或与主应力垂直。影响焊接应力的主要因素有: 1.焊接温度的影响焊接应力的大小与焊接温度
Cast iron welding characteristics Cast iron has high carbon content and silicon content, low strength, poor plasticity, large coefficient of expansion, heating and cooling have a higher sensitivity, is a poor weldability of the material. Welding often crack, white and stomatal defects. First, the causes of cracks and prevent the lower strength of cast iron, poor plasticity, so in the cooling process after welding, the welding zone stress continues to increase, when the welding stress exceeds the strength limit of cast iron, the sudden fracture or weld and Base material stripping, sometimes accompanied by “carbazole ” sound. Cracks may also appear near welds, weaknesses, or sharp corners where stresses tend to concentrate. Crack direction is along the weld or perpendicular to the principal stress. The main factors that affect the welding stress are: 1. The influence of the welding temperature The size of the welding stress and the welding temperature