镀锌方矩管具备抗腐蚀和使用期长的双向优势，并且价钱相对性较低，因此如今它的利用率也愈来愈高，可是一些人在焊接镀锌管时不留意，导致了一些不便，那麼焊接镀锌管时应当留意哪些难题呢？

　　Galvanized square and rectangular pipes have the advantages of corrosion resistance and long service life, and have a relatively low price. Therefore, their utilization rate is increasing. However, some people do not pay attention to welding galvanized pipes, which has caused some inconvenience. So, what difficulties should be paid attention to when welding galvanized pipes?

　　1、前提是要打磨

　　1. The prerequisite is to polish it

　　电焊焊接处的热镀锌层务必打磨抛光掉，不然会出現汽泡、沙眼、假焊等。将会造成。这也将使焊缝变脆并减少其刚性。

　　The hot-dip galvanized layer at the welding point must be polished off, otherwise bubbles, sand holes, false welding, etc. may occur. It will cause. This will also make the weld brittle and reduce its rigidity.

　　2、镀锌方矩管的特点

　　2. Characteristics of galvanized rectangular pipes

　　镀锌钢一般在高碳钢的外边涂上一层锌，热镀锌层一般为20um厚。锌的熔点为419℃，沸点为908℃在电焊焊接中，锌熔化成液体，飘浮在溶池表面或焊接根处。锌在铁中有挺大的固溶度，锌液会沿晶界深层浸蚀焊接金属，低溶点锌会产生“形状记忆合金脆裂”。

　　Galvanized steel is usually coated with a layer of zinc on the outer edge of high carbon steel, and the hot-dip galvanized layer is generally 20um thick. The melting point of zinc is 419 ℃ and the boiling point is 908 ℃. In electric welding, zinc melts into a liquid and floats on the surface of the molten pool or at the welding root. Zinc has a significant solid solubility in iron, and the zinc solution will deeply corrode the welded metal along the grain boundaries. Low melting point zinc will cause "shape memory alloy brittle fracture".

　　如果焊接角焊缝，尤其是T形接头的角焊缝最容易产生穿透裂纹。镀锌钢电焊焊接时，坡口表面和边沿的锌层在电孤加温的功效下能造成空气氧化、熔融、挥发，乃至冒烟和蒸气的蒸发，非常容易导致焊接出气孔。

　　If welding fillet welds, especially T-joint fillet welds, it is most likely to produce penetrating cracks. When welding galvanized steel, the zinc layer on the groove surface and edge can cause air oxidation, melting, volatilization, and even smoke and vapor evaporation under the effect of electric arc heating, which can easily lead to welding porosity.

　　空气氧化产生的氧化锌熔点高过1800℃，假如电焊焊接全过程中的主要参数不大，就会造成氧化锌渣参杂物。次之，因为锌的挥发，很多冒烟蒸发，对身体有刺激性和损害功效。因而，电焊焊接处的热镀锌层务必打磨和解决。

　　The melting point of zinc oxide produced by air oxidation is higher than 1800 ℃. If the main parameters during the entire welding process are not large, it will cause zinc oxide slag impurities. Secondly, due to the volatilization of zinc, a lot of smoke evaporates, which has irritating and damaging effects on the body. Therefore, the hot-dip galvanized layer at the welding point must be polished and resolved.

　　3、镀锌方矩管焊接工艺控制

　　3. Welding process control of galvanized square and rectangular pipes

　　电焊焊接前镀锌钢的制取与一般高碳钢同样。应留意当心解决带槽规格和周边的热镀锌层。以便焊透，坡口规格尽可能，一般为60~65，留出一定空隙，一般为1.5~2.5mm；以便降低锌渗入焊接中，能够在电焊焊接前往除带槽中的热镀锌层。在实际上工作上，选用集中化倒圆角、无钝边技术性和两层焊接工艺开展集中控制，减少了电焊焊接不彻底的概率。金属电极应依据热镀锌硬管的PCB原材料挑选。

　　The preparation of galvanized steel before welding is the same as that of general high carbon steel. Attention should be paid to resolving issues with groove specifications and the surrounding hot-dip galvanized layer. In order to facilitate welding penetration, the groove specification should be as large as possible, usually 60-65, leaving a certain gap, usually 1.5-2.5mm; in order to reduce zinc infiltration into the welding, the hot-dip galvanized layer in the groove can be removed during electric welding. In practical work, centralized control is carried out using centralized rounded corners, non blunt edge technology, and two-layer welding processes to reduce the probability of incomplete electric welding. Metal electrodes should be selected based on the PCB raw materials of hot-dip galvanized hard pipes.

　　4、镀锌方矩管焊接手法

　　4. Welding technique for galvanized rectangular pipes

　　当电焊焊接第一层多层高层电焊焊接时，尽可能使锌层熔融、挥发并从焊缝中逸出，那样能够大大减少残余在焊缝中的液体锌。角焊缝电焊焊接时，锌层应尽量在第一层熔化，挥发并挥发以从焊接中逸出。方式是将焊丝尾端往前挪动约5~7mm，随后在熔化锌层后返回原先的部位再次往前电焊焊接。针对水准电焊焊接和竖直电焊焊接，假如挑选短炉渣金属电极，如J427，底切发展趋势将十分小。假如选用前后左右带材运送技术性，能够得到无缺点的镀锌方矩管焊接品质.

　　When welding the first layer of multi-layer high-rise welding, try to melt, evaporate and escape the zinc layer from the weld seam as much as possible, which can greatly reduce the residual liquid zinc in the weld seam. When welding fillet welds, the zinc layer should be melted as much as possible in the first layer, volatilized and evaporated to escape from the weld. The method is to move the end of the welding wire forward by about 5-7mm, and then return to the original position after melting the zinc layer and welding it forward again. For horizontal and vertical welding, if short slag metal electrodes such as J427 are selected, the trend of bottom cutting development will be very small. If the use of front, back, left, and right strip transportation technology is adopted, it can achieve defect free welding quality of galvanized square rectangular pipes

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