三峡工程压力钢管下平段凑合节合拢缝选型试验

The selection of joint shape of the last annular weld of the steel-penstocks of Three Gorges Project

三峡工程1～6号无伸缩节压力钢管凑合节合拢焊缝是高强调质钢厚板在强约束条件下的焊接,技术难度很大,其合拢缝结构形式的选型将是三峡压力钢管施工成功的关键技术之一,为此,进行了合拢缝在拘束应力情况下搭接和对接两种方案的选型试验,最终选择了对接接头形式。4号压力钢管下平段凑合节合拢缝对接焊接的应用实例,证明这种方案是可行的。

The weld of the thick hardened and tempered steel-plate of high-tensile was difficult to accomplish technically, belonging to the steel-penstocks of No.1～6 water turbines of the Three Gorges Project, with the conditions of high restriction. The selection of joint shape of the last annular weld was the key to the construction of steel-penstocks. The experiments of two shapes of the last annular weld, butt joint and overlap joint, were done comparatively. As a result, the butt joint was considered as the optimal shape of the last annular weld. This article puts emphasis on the selection of joint shape.