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为了解决30CrMo锻焊曲轴的焊接质量问题,研究了焊接热输入对30CrMo钢焊接接头力学性能的影响规律,并针对焊条电弧焊(SMAW)和CO_2气体保护焊(GMAW)两种方法,找出了适合的焊接热输入范围。结果表明:随着热输入的增加,采用焊条电弧焊和CO_2气体保护焊的焊接接头抗拉强度均呈现下降趋势;采用焊条电弧焊的焊缝区和热影响区冲击功先增加后减小;采用CO_2气体保护焊的焊缝区冲击功减小,而热影响区冲击功先增加后减小;采用焊条电弧焊的热影响区硬度呈下降趋势,采用CO_2气体保护焊的热影响区硬度变化较小;采用两种焊接方法的焊缝区域硬度值总体呈降低趋势。当预热温度为220℃,热输入在8~24 kJ/cm范围内,采用焊条电弧焊和CO_2气体保护焊的焊接接头抗拉强度均能满足要求;热影响区及焊缝区域硬度值均低于350HV,不易产生冷裂纹。该工艺参数范围已成功应用于某30CrMo锻焊曲轴的焊接中,焊接质量良好,满足质量要求。
In order to solve the welding quality problem of 30CrMo forge welding crankshaft, the influence of welding heat input on the mechanical properties of 30CrMo steel welded joints was studied. According to the welding arc welding (SMAW) and CO_2 gas shielded welding (GMAW) Suitable welding heat input range. The results show that with the increase of heat input, the tensile strength of welded joints with arc welding and CO_2 gas shielded welding showed a downward trend; the weld joint and heat affected zone using the electrode arc welding first increased and then decreased; The impact energy of weld zone with CO_2 gas shielded welding is reduced, while the impact energy of heat affected zone first increases and then decreases. The hardness of heat affected zone (HAZ) decreases with the arc welding of welding rod. The hardness of heat affected zone Smaller; the weld zone hardness of two kinds of welding methods generally showed a decreasing trend. When the preheating temperature is 220 ℃ and the heat input is in the range of 8 ~ 24 kJ / cm, the tensile strength of the welded joint by arc welding and CO_2 gas shielded welding can meet the requirements; both the heat affected zone and the weld zone hardness Less than 350HV, not easy to produce cold cracks. The process parameters of the range has been successfully applied to a 30CrMo forging welding crankshaft welding, welding quality, to meet the quality requirements.