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在焊工考试中,AⅠ-21位试件(管状水平固定试件)常见的缺陷是根部缩孔。这种缺陷往往是大量、连续的,产生的部位以10点到2点之间最为严重。在灭弧焊法操作中,一般采用下述方法防止缩孔:①加快灭弧频率,以减少缩孔形成的机会;②降低焊接速度,增厚打底焊道,以使灭弧时产生的缩孔在再引弧过程中被充分熔化。这两种方法,虽然对控制缩孔的产生有一定的作用,但因操作难度较大,稍有不慎,仍有缩孔产生。
In the welder examination, A Ⅰ-21-bit specimen (tubular horizontal fixed specimen) common defect is the root shrinkage. This type of defect is often massive and continuous, with the site being most severely affected between 10 and 2 o’clock. In the arc welding operation, the following methods are generally used to prevent cratering: ① to speed up the frequency of arc extinguishing in order to reduce the chance of shrinkage; ② reduce the welding speed, thickened backing bead so that the arc generated Shrinkage in the re-arc process is fully melted. These two methods, although the production of shrinkage control to a certain extent, but due to the operation more difficult, a little careless, there are still shrinkage generated.