精密无缝钢管安装使用有哪些应注意事项?

　　精密无缝钢管安装前的施工准备?管道沟应按图纸要求挖好，管道井砌砖完毕，需要的各种型号精密无缝钢管已到货，质量完好无损，并检验合格，所需要的施工用的工具，包括电焊机、切割机、电锤、磨光机等准备齐全，只有做好一系列的准备工作才能开始安装。

　　Construction preparation before installation of cold-drawn steel pipe? Pipeline trench should be excavated in accordance with the requirements of the drawings, the bricklaying of pipeline wells has been completed, the various types of cold-drawn steel pipes needed have arrived, the quality is intact, and the inspection is qualified. The required construction tools, including welding machines, cutting machines, hammers, polishers and so on, are well prepared. Only a series of preparatory work can start installation.

　　二、精密无缝钢管安装过程

　　II. Installation Process of Cold Drawn Steel Pipe

　　根据图纸设计进行管道定位，根据现场情况预制管道支架，然后根据设计和现场进行下料，然后用磨光机磨坡口，再进行焊接。焊接时将带钢送入焊管机组，经多道轧辊滚压，带钢逐渐卷起，形成有开口间隙的圆形管坯，调整挤压辊的压下量，使焊缝间隙控制在1~3mm，并使焊口两端齐平。如间隙过大，则造成邻近效应减少，涡流热量不足，焊缝晶间接合不良而产生未熔合或开裂。如间隙过小则造成邻近效应增大，焊接热量过大，造成焊缝烧损;或者焊缝经挤压、滚压后形成深坑，影响焊缝表面质量。

　　Pipeline positioning is carried out according to the design of the drawings. Pipeline brackets are prefabricated according to the site conditions. Then the blanking is carried out according to the design and the site. Then the groove is ground by a polisher and welded. When welding, the strip is fed into the welded pipe unit. After rolling by multi-rollers, the strip is gradually rolled up to form a circular billet with an opening gap. The reduction of the extrusion roll is adjusted so that the weld gap is controlled at 1-3 mm and the weld ends are even. If the gap is too large, the proximity effect will be reduced, the eddy current heat is insufficient, and the weld crystals will not fuse or crack indirectly. If the gap is too small, the proximity effect will increase, the welding heat will be too large, which will cause the welding seam burning; or the deep pit will be formed after the welding seam is extruded and rolled, which will affect the surface quality of the welding seam.

　　三、精密无缝钢管安装质量检验

　　Inspection of Installation Quality of Cold Drawn Steel Pipe

　　1、焊缝处不得焊接支管，弯曲处避免有焊缝。

　　1. No bracket shall be welded at the weld seam, and no weld shall be found at the bend.

　　2、垂直安装的立管每米偏差应小于3毫米，水平安装的偏差应小于1毫米。

　　2. The deviation of vertical installation riser per meter should be less than 3 mm, and that of horizontal installation should be less than 1 mm.

　　3、直缝焊管表面质量应光滑，不允许有折叠、裂缝、分层、搭焊等缺陷存在。直缝管表面的划道、刮伤、焊缝错位、烧伤和结疤等轻微缺陷不得超过壁厚负偏差。

　　3. The surface quality of straight seam welded pipe should be smooth, and no defects such as folding, cracking, delamination and lap welding should be allowed. The slight defects such as scratches, scratches, weld dislocation, burns and scars on the surface of straight seam pipes shall not exceed the negative deviation of wall thickness.