back bead

基本解釋

This welding backing is used with all one-side processes. Especially for those which do not demand back bead cleaning.
本襯墊可用于各種單面焊接工藝的位置，特別適用于不一定要求封底焊道的場(chǎng)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.
壓力管道TIG焊在焊接中焊道背部易出現(xiàn)缺陷，用反向送絲的方法成功地解決了這一問(wèn)題。
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.
不論熔透控制還是焊縫跟蹤，都需要實(shí)時(shí)或離線提取焊接熔池正面或反面的幾何參數(shù)。

So you can imagine a bead with a wire going through it and the bead can only slide back and forth.
你可以想象一個(gè)穿在繩子上的珠子,小珠只能前后滑動(dòng)
耶魯公開(kāi)課 - 基礎(chǔ)物理課程節(jié)選