Stainless steel pipe operation process method?

 Common welding defects Prevention

1. Slag inclusion: the current is too small, the electrode angle is incorrect, the conveying rod speed is too fast, the arc voltage is too low

2. Undercut: the current is too large, the electrode angle cannot be changed in time, the arc starting time is too long, the arc striking is uneven.

3. Weld deflection: the electrode angle is correct the lower edge swings too much.

4. Rough weld: the current is too large, the angle of welding rod is correct, the distance between conveying bars is too large, the speed is uneven.

5. The external dimension does meet the requirements: the excess width of metal at the edge of the plate should be controlled in the second layer. The second step is to control the height of welding feet.

Operation technology method of stainless steel pipe

1. Assembly spot welding of test piece

1. Clean the specimen

Clean oil, rust, water other contaminants the side of the tube the edge of the plate within 25 mm until metallic luster is revealed.

2. Specimen assembly positioning welding

Put the test piece on the assembly platform, use the welding rod to weld the formal weld for spot welding. The tube should be placed in the middle of the circuit board. The length of tack welding is 10-15mm, spot welding is carried out on the pipe wall. Spot welding shall be firm to prevent cracking.

2、 Key points of operation

(1) Play bottom layer

1. Arc starting method: the starting point is opposite to the positioning weld, the arc is ignited at the side 10-15mm in front of the starting point. Once the arc is ignited, press it down immediately perform short arc operation, then reach the welding starting point. In this way, pores can be avoided at the starting point of the weld can be eliminated by remelting the starting point of the arc.

2. Operation method: keep short arc operation during welding. Use zigzag linear transportation methods. The swing amplitude should be kept at about 6 mm will be slightly suspended when swinging to the side of the pipe to ensure the root is fully welded. During welding, the electrode angle should be basically consistent the welding speed should be uniform.

3. Joint method: lead the arc to 10 mm in front of the crater, pull it to the crater, swing horizontally along the shape of the crater to fill the crater, make the weld match the crater contour, when the swing width reaches the weld width, please keep normal welding. Joint movement should be fast, quick skilled to avoid high disconnection.

4. Arc closing method: in order to avoid shrinkage cavity, shrinkage cavity other defects, the molten pool should be guided slow speed to plate side.

(2) Covering surface layer (one layer): before welding, the welding slag spatter of a layer of weld bead shall be removed by zigzag strip method. The swing amplitude is about 8 mm, the swing shall stop at the edge of the pipe plate for a while, so as to ensure that the welding feet on the side of the pipe are 3 to 5 mm, slow down the forward speed in the welding process, so as to form a stepped weld, In order to support the next welding, which is beneficial to the covered surface. Smooth transition between weld passes.

Covering the surface layer (two layers): using a smaller zigzag conveyor belt method, the swing amplitude is maintained at about 4 meters. In the welding process, the lower edge of the weld pool should be controlled to cover two thirds of the weld, then it should be left on the side of the pipe to make the weld leg size reach 5-8 mm. The method of arcing, jointing finishing is the same as that of the first layer.