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本文对低组配焊接接头的机理和接头性能等两个方面进行了分析研究。低组配焊接接头静拉伸的力学性能,受焊缝金属的相对厚度所影响,随着相对厚度的减小,接头的拉伸强度由焊缝金属的拉伸强度增至基本金属的拉伸强度。接头强度还随低组配焊接接头的板宽改变而变化,板宽增大、接头拉伸强度增加,直至板宽大于五倍板厚时为止。故低组配焊接接头拉伸强度能以含有相对厚度和焊缝金属对基本金属的强度比的公式所计算。在厚板低合金高强钢的焊接中,与采用高组配焊条相比,用低组配焊条能有效的降低为防止由第一道焊道所引起的焊根裂纹所需要的予热温度。并且,该种接头在多道连续焊时引起的焊缝裂纹,对于接头的大拘束度并不敏感。为防止焊缝金属裂纹所需要的予热温度用低组配焊条比用高组配焊条大约降低七十余度。
In this paper, the mechanism of low-assembly welding joint and joint performance are analyzed in two aspects. The mechanical properties of low tensile strength welded joints are affected by the relative thickness of the weld metal. As the relative thickness decreases, the tensile strength of the joint increases from the tensile strength of the weld metal to that of the base metal strength. The strength of the joint also varies with the width of the low-profile welded joint, the width of the joint increases, and the tensile strength of the joint increases until the width of the joint is larger than five times the thickness of the joint. Therefore, the tensile strength of a low-profile welded joint can be calculated as a formula containing the relative thickness and the ratio of the strength of the weld metal to the base metal. In the plate low alloy high strength steel welding, compared with the use of high grouping of electrodes, the use of low grouping of electrodes can effectively reduce the first pass to prevent the weld root cracks caused by the required preheating temperature. And, this type of joint in the multi-continuous welding caused by weld cracks, the joints for a large degree of restraint is not sensitive. In order to prevent weld metal cracks needed to preheat the temperature with a lower than the number of electrodes with a high group of electrodes to reduce about 70 degrees.