管道是各种设备不可缺少的一部分，管道广泛应用于石油、化工及各种装置和设备中。管道焊接的质量直接影响到设备的正常运行。今天，我们将讨论管道的焊接工艺。
Pipeline is an indispensable part of various equipment. Pipelines are widely used in petroleum, chemical industry and various devices and equipment. The quality of pipeline welding directly affects the normal operation of equipment. Today, we will discuss the welding process of pipes.
管道的焊条电弧焊：管道的焊条电弧焊是目前一般工厂最常用的焊接方法。它是一种通过人工操作熔化管壁和焊条，混合形成熔池并凝固形成焊缝方法。焊条电弧焊设备简单、灵活、应用方便，适用于小直径管道、薄壁管道和狭窄管道的焊接。焊条电弧焊可应用于任意的空间和位置。
Welding rod arc welding of pipeline: welding rod arc welding of pipeline is the most commonly used welding method in general factories at present. It is a method of manually melting pipe wall and welding rod, mixing to form molten pool and solidification to form weld. The electrode arc welding equipment is simple, flexible and easy to apply. It is suitable for the welding of small-diameter pipes, thin-wall pipes and narrow pipes. Electrode arc welding can be applied to any space and position.
1、管道的转动焊接：在预制厂加工管道时，一般采用转动焊接，操作简单，生产率高。管道焊接质量与对接和点焊密切相关。
Rotary welding of pipeline: when processing pipeline in prefabrication plant, rotary welding is generally adopted, which has simple operation and high productivity. Pipe welding quality is closely related to butt welding and spot welding.
2、管道对口及定位焊：管道对口焊的规范应符合国家企业的相关标准。同时，坡口端面的平面度应小于0.5毫米，接头装配错位不应大于1毫米，对于小直径的管道，只需在管道对称两侧定位焊即可。对于大直径的管道，可以点焊三个或三个以上的焊点，并应确定点焊焊点的尺寸。当管壁厚度小于或等于5毫米时，那么焊点的厚度为2.5-3毫米，如果管壁厚度大于5毫米，焊点的厚度约为4到5毫米，点焊的长度约为20-30毫米，为了便于接头的穿透，焊点的两端必须做成缓坡形状。
2. Pipe butt welding and tack welding: the specification of pipe butt welding shall comply with the relevant standards of national enterprises. At the same time, the flatness of the groove end face shall be less than 0.5mm, and the joint assembly dislocation shall not be more than 1mm. For small-diameter pipes, it is only necessary to conduct tack welding on both symmetrical sides of the pipe. For large diameter pipes, three or more welding spots can be spot welded, and the size of the spot welding spot shall be determined. When the pipe wall thickness is less than or equal to 5mm, the thickness of the welding spot is 2.5-3mm. If the pipe wall thickness is greater than 5mm, the thickness of the welding spot is about 4-5mm, and the length of the spot welding is about 20-30mm. In order to facilitate the penetration of the joint, both ends of the welding spot must be made into a gentle slope shape.
3、根部焊接：无垫片的管子转动焊接。为了使根部易于穿透，运条范围应选择在垂直焊接位置。操作方法可以是直线的，也可以是稍微摆动的月牙形。如果对接接头之间的间隙较大，可以采用灭弧方法进行焊接。对于厚壁管道，有时转动很费力。同时，为了防止转动时因振动而在接头根部产生裂纹，并便于操作，在对接前应将管子放在平坦的转动台上。焊接时，最好在转动一次之前。同时，焊缝必须有足够的强度，靠近接头的两个支点之间的距离不应超过管径的1.5-2倍。
3. Root welding: rotary welding of pipes without gaskets. In order to make the root easy to penetrate, the strip transportation range shall be selected at the vertical welding position. The operation method can be linear or slightly swinging crescent. If the gap between butt joints is large, arc extinguishing method can be used for welding. For thick walled pipes, sometimes the rotation is very laborious. At the same time, in order to prevent cracks at the root of the joint due to vibration during rotation and facilitate operation, the pipe shall be placed on a flat rotating table before docking. When welding, it is better to weld before turning once. At the same time, the weld must have sufficient strength, and the distance between two fulcrums close to the joint shall not exceed 1.5-2 times of the pipe diameter.
