Defects And Correction Methods of Automatic Welding Vertical Welding of Large Storage Tank

Defect 1, Appearance defect

1. The inner surface of the weld is incomplete

A. The surface size of the groove is greater than the size of the copper slider

B. The welding voltage is less than the specified value

C. The welding wire is too close to the root

2. The edge of the weld appears convex (not smooth transition)

A. The upper and lower size of the groove is much smaller than the size of the copper slider

B. There is a gap between the copper slide and the steel plate (under normal circumstances, the sliding copper block is 7-9mm larger than the upper end of the groove and the copper slide is mirrored with the steel plate

The clamping force can be adjusted by the handwheel, the guide rod is parallel to the handwheel face, and the clamping degree can be a copper sheet.)

3. Weld surface to one side

A. The center of the sliding copper block is offset from the center of the groove

B. The misopening of the two steel plates is large

Defect 2, Non-fusion, generally non-fusion occurs on the side of the weld more.

The main reasons are:

A. The voltage is below the specified value

B. The welding wire swings to one side

C. The copper backing block is offset from the center

D. The groove clearance is too small

E. The end of the welding wire is bent

The solution:

Before operation, the welding wire must swing in the center of the groove, and adjust the current and voltage according to the specification, and at the same time in the welding process fine tuning, because the size of the sliding copper head is certain, the upper deviation size of the V-groove is 16-18mm.

Defect 3, The generation of pores (more strip pores)

The main reason:

A. The purity of the protective gas CO2 is not enough, and the water content exceeds the standard

B. The gas flow is too large or too small, the appropriate flow rate is 30L/min

C. The location of the metal melt pool is inappropriate

D. Copper plate leakage or water splashing in the groove

E. The glass cloth is wet

F. Water vapor attached in the fracture

Defect 4, Weld inclusion crack

The weld crack is transverse distribution, the width is 0.5-2mm, there are inclusions in the seam, and the depth is 2-3mm from the surface. The above phenomenon is caused by improper operation.

The main reasons are:

A. The copper slider does not rise evenly and has A sharp beating phenomenon

B. The welding wire is too close to the copper slider

Solution: Before welding, it is necessary to check the surface of the steel plate passed by the copper slide, so that there is no splash and other things that hinder the slide, so that the copper slide can remain stable. Determine the swing of the welding wire: swing = T-12mm (t is the thickness of the plate), in the case of V-groove to the most front A distance from the sliding copper block 4-6mm cross, if less than 4mm will appear surface inclusion cracks, or even damage the copper slide.

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