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Shanghai Gaochuan Valve Manufacturing Co., Ltd.

Address: No. 2465, Hengcang Road, Malu Town, Jiading District, Shanghai

Phone 1: 021-56772777 

Phone 2: 021-56521514 

Phone 3:021-56521504

Fax: 021-56770777

QQ: 49453698

E-MAIL: gcvalve@126.com


Welding technology and method of large-diameter vacuum flange

2021-04-20 01:57:40


In the welding engineering of large diameter vacuum flange , there is only one welding port, but considering the welding deformation and welding quality, the X-shaped groove is adopted. First, fix the ring blank horizontally on the gantry fixture platform, and perform the groove processing. The groove processing is first cut with flame, and then ground with a grinder. The groove surface is smooth and flat without obvious grooves. The groove surface is smooth and flat. The side has no defects such as iron oxide, impurities, moisture, oil stains, and layers.

Due to the thicker billet, the selection of a suitable welding method directly affects the degree of welding deformation. Choose manual welding for symmetrical welding on both sides.

If the large diameter flange is improperly welded, deformation may still occur after welding. For example, first weld one side of the x groove, and then weld the other side; when one side is welded first, the structural rigidity is relatively small, and the welding deformation is relatively large. When the back side is welded, the front side weld has been formed, and the structural rigidity is greatly improved. At this time, the amount of deformation caused by welding is smaller than the front side. Although the deformation directions of the two are opposite, they cannot be fully offset, and the deformation direction of one surface is maintained as a result. Determine the number of welding layers according to the thickness of the welding workpiece and the diameter of the electrode. The thickness of the workpiece in this example is 50 mm, divided into 10 layers, each with 5 layers. The welding adopts positive and anti-symmetric welding. After each layer of welding is completed, the weld is hammered several times. After the weld is sufficiently cooled, the fixture is removed to remove the welding stress as much as possible.

After the welding of the large diameter flange is completed, a comprehensive RT or UT inspection should be carried out according to the requirements of JN4700. Since the welded part is the part where the stress is concentrated and the flange strength is relatively weak, non-destructive testing should be carried out and meet the grade requirements. The UT inspection should reach the first level or the second level, and the inspection method should meet the requirements of JB4730.




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 Address: No. 2465, Hengcang Road, Malu Town, Jiading District, Shanghai

Phone: 021-56772777 56521514 56521504

 Fax:021-56770777          QQ:49453698