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一、钢管的焊接方法的发展近几年来,世界各国在钢管焊接工艺上有了重大的改革。普遍在原低频焊管的基础上发展为100～450仟周/秒的高频电阻接触焊和感应焊。这种焊接工艺的特点是:金属在加热时电能的高度集中,用1/10甚至~1/100秒就可以使金属加热到焊接温度(1300～1350℃)。由于高频电流的集肤效应和邻近效应,焊接电流将沿管坯边缘很薄的一层通过,因此,热影响区窄,加热时间短,从而生成的氧化物减少,这就为提高焊接质量创造了有利条件。实践证明,采用频率为450仟周/秒的高频电流焊管同低频焊管比较具有许多优点:
First, the development of the welding method of steel pipe In recent years, all countries in the world in the steel pipe welding process has been a major reform. Generally in the original low-frequency welded pipe on the basis of the development of 100 to 450 thousand weeks / second high-frequency resistance contact welding and induction welding. The characteristic of this welding process is that the metal is highly concentrated when heated, and the metal can be heated to the soldering temperature (1300-1350 ° C) with 1/10 or even 1/100 seconds. Because of the skin effect and proximity effect of high-frequency current, the welding current will pass through a very thin layer along the edge of the tube. As a result, the heat-affected zone is narrow and the heating time is short, resulting in a reduction of oxide formation, which results in improved weld quality Created favorable conditions. Practice has proved that the use of frequency of 450 thousand weeks per second high-frequency current welded pipe with low-frequency welded pipe has many advantages: