back bead

基本解释

This welding backing is used with all one-side processes. Especially for those which do not demand back bead cleaning.
本衬垫可用于各种单面焊接工艺的位置，特别适用于不一定要求封底焊道的场合。
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It easy to occur defect on the back of bead in pressure pipe TIG welding, which can be solved by using the anti, direction wire feeding method successfully.
压力管道TIG焊在焊接中焊道背部易出现缺陷，用反向送丝的方法成功地解决了这一问题。
It is necessary to extract molten pool geometrical parameters in real time or to extract back bead width off-line either in seam tracking or in penetration control.
不论熔透控制还是焊缝跟踪，都需要实时或离线提取焊接熔池正面或反面的几何参数。

So you can imagine a bead with a wire going through it and the bead can only slide back and forth.
你可以想象一个穿在绳子上的珠子,小珠只能前后滑动
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