精密無縫鋼管安裝前的施工準備?管道溝應按圖紙要求挖好，管道井砌磚完畢，需要的各種型號精密無縫鋼管已到貨，質量完好無損，并檢驗合格，所需要的施工用的工具，包括電焊機、切割機、電錘、磨光機等準備齊全，只有做好一系列的準備工作才能開始安裝。

　　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、精密無縫鋼管安裝過程

　　II. Installation Process of Cold Drawn Steel Pipe

　　根據圖紙設計進行管道定位，根據現場情況預制管道支架，然后根據設計和現場進行下料，然后用磨光機磨坡口，再進行焊接。焊接時將帶鋼送入焊管機組，經多道軋輥滾壓，帶鋼逐漸卷起，形成有開口間隙的圓形管坯，調整擠壓輥的壓下量，使焊縫間隙控制在1~3mm，并使焊口兩端齊平。如間隙過大，則造成鄰近效應減少，渦流熱量不足，焊縫晶間接合不良而產生未熔合或開裂。如間隙過小則造成鄰近效應增大，焊接熱量過大，造成焊縫燒損;或者焊縫經擠壓、滾壓后形成深坑，影響焊縫表面質量。

　　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、精密無縫鋼管安裝質量檢驗

　　Inspection of Installation Quality of Cold Drawn Steel Pipe

　　1、焊縫處不得焊接支管，彎曲處避免有焊縫。

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

　　2、垂直安裝的立管每米偏差應小于3毫米，水平安裝的偏差應小于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、直縫焊管表面質量應光滑，不允許有折疊、裂縫、分層、搭焊等缺陷存在。直縫管表面的劃道、刮傷、焊縫錯位、燒傷和結疤等輕微缺陷不得超過壁厚負偏差。

　　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.