| 摘要 |
A welding method for joining self-supporting structures made of thermoplastics by assembling said structures to form an area of mutual overlap, generating heat in said area to produce a welding zone having an elevated temperature and containing said thermoplastics in an at least plastic state for mutual coalescence of said structures in said area; an expanding agent is provided in the welding zone to generate a gas pressure therein for promoting coalescence of the weld. The invention is particularly suitable for welding tubes and other pipeline elements, such as fittings or sleeves, of thermoplastics and produces a tumescent weld which fills any macroscopic voids while including a plurality of minute closed cell voids. |
