在焊管焊接过程中，埋弧焊也是利用电弧作为热源的焊接方法。埋弧焊时电弧是在一层颗粒状的可熔化焊剂覆盖...埋弧焊电源一般应具有陡降外特性，可用交流(弧焊变压器)、直流(弧焊发电机或弧焊整流器)或交、直流并用。当焊丝确定以后(通常取决于所焊的钢种)，配套用的焊剂则成为关键材料，它直接影响焊缝金属的力学性能(特别是塑性及低温韧性)、抗裂性能、焊接缺陷发生率及焊接生产率等。焊丝与焊剂的配用重量比为焊丝：焊剂=1.1～1.6，视焊接接头类型、所用焊剂种类、焊接规范参数而定。与熔炼焊剂相比，烧结焊剂用量较为节省，约可少用20%左右。
Submerged arc welding (SAW) is also a welding method using arc as heat source in the welding process of welded pipe. When submerged arc welding, the arc is covered by a layer of granular fusible flux. Submerged arc welding power supply should generally have steep drop characteristics. It can be used in AC (arc welding transformer), DC (arc welding generator or arc welding rectifier) or AC/DC combination. When the welding wire is determined (usually depending on the type of steel being welded), the matching flux becomes the key material, which directly affects the mechanical properties (especially plasticity and low temperature toughness), crack resistance, occurrence rate of welding defects and welding productivity of the weld metal. The weight ratio of welding wire to flux is wire: flux = 1.1-1.6, depending on the type of welding joint, the type of flux used and the welding specification parameters. Compared with smelting flux, the amount of sintered flux is less, about 20% less. 单丝埋弧焊在焊管焊接时由于焊接熔池体积小、质量小、存在时间短、结晶冷却速度快，在一定的焊接规范下，焊速受到限制，一般为300~600mm/min,过快的焊速极易导致熔池冷却结晶速度快而产生焊接缺陷，过慢的速度又导致热输入过大、热影响区增宽而使接头性能下降、生产效率低。而多丝埋弧焊大都是多丝纵向串列，在焊接过程中形成一个共用熔池，三丝焊时熔池长度即可达到80~100mm以上，熔池存在时间长、冶金反应充分，有充裕的时间供气体和杂质浮出。焊接质量好，只要工艺和规范控制的好，焊接缺陷很少。焊速可达到1.0~2m/min以上,生产效率高。比单丝埋弧焊高3~5倍。
Single wire submerged arc welding (SSAW) for welded pipes is characterized by small weld pool volume, small quality, short existence time and fast crystallization cooling speed. Under certain welding specifications, the welding speed is limited. Generally, the welding speed is 300-600 mm/min. Over-fast welding speed can easily lead to rapid crystallization rate of weld pool cooling and welding defects. Over-slow welding speed also leads to excessive heat input and widening of heat affected zone, which results in joint performance. Decreased production efficiency. The multi-wire submerged arc welding is mostly multi-wire longitudinal series, forming a common molten pool in the welding process. The length of the molten pool can reach more than 80-100 mm during three-wire welding. The molten pool exists for a long time, the metallurgical reaction is sufficient, and there is sufficient time for gas and impurities to float out. Welding quality is good, as long as the process and specifications are well controlled, there are few welding defects. The welding speed can reach more than 1.0~2 m/min, and the production efficiency is high. It is 3 to 5 times higher than single wire submerged arc welding.
埋弧焊(含埋弧堆焊及电渣堆焊等)是一种电弧在焊剂层下燃烧进行焊接的方法。其固有的焊接质量稳定、焊接生产率高、无弧光及烟尘很少等优点，使其成为压力容器、管段制造、箱型梁柱等重要钢结构制作中的主要焊接方法。近年来，虽然先后出现了许多种高效、优质的新焊接方法，但埋弧焊的应用领域依然未受任何影响。
Submerged arc welding (including submerged arc surfacing and electroslag surfacing) is a method of arc combustion under flux layer for welding. Because of its inherent advantages of stable welding quality, high welding productivity, no arc and little smoke, it has become the main welding method in the manufacture of important steel structures such as pressure vessels, pipe sections and box-shaped beams and columns. In recent years, although there have been many new welding methods with high efficiency and quality, the application field of SAW has not been affected.
焊管的多丝埋弧焊是指使用两根或两根以上焊丝完成同一焊缝的埋弧焊。焊管的多丝埋弧焊机组焊接装置：内焊装置由机械系统、电气控制系统、焊接系统、焊剂供给及回收系统、摄像监视系统五部分组成。其中机械系统主要包括：焊接机头、悬臂梁、悬臂梁支撑机构、焊缝跟踪调节系统、机座及地线升降架等。
Multi-wire submerged arc welding of welded pipe refers to submerged arc welding of the same weld with two or more welding wires. Welding device of multi-wire submerged arc welding machine for welded pipe: The internal welding device consists of five parts: mechanical system, electrical control system, welding system, flux supply and recovery system, video surveillance system. The mechanical system mainly includes: welding head, cantilever beam, cantilever beam support mechanism, seam tracking adjustment system, machine base and wire lifting frame, etc.
焊丝的倾斜方向分为前倾和后倾。倾角的方向和大小不同，电弧对熔池的力和热作用也不同，从而影响焊缝成形。当焊丝后倾一定角度时，由于电弧指向焊接方向，使熔池前面的焊件受到了预热作用，电弧对熔池的液态金属排出作用减弱，而导致焊缝宽而熔深变浅。反之，焊缝宽度较小而熔深较大，但易使焊缝边缘产生未熔合和咬边，并且使焊缝成形变差。
The inclination direction of welding wire can be divided into forward inclination and backward inclination. The direction and size of inclination angle are different, and the force and heat effect of arc on molten pool are also different, thus affecting the weld formation. When the welding wire is inclined backward at a certain angle, the welding parts in front of the molten pool are preheated because the arc points to the welding direction, and the discharge of liquid metal from the molten pool is weakened by the arc, which results in the weld width and shallow penetration. On the contrary, the weld width is smaller and the penetration is larger, but it is easy to cause the weld edge to produce unfused and undercut edges, and make the weld formation worse.
