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Preparation before welding for clad plates
Aug 03, 2018


1. Cutting

The cutting and beveling of stainless steel clad steel plates should be mechanically processed as much as possible. The cutting surface should be smooth. When cutting with a shearing machine, the clad layer should be facing upwards. Plasma cutting can also be used. When cutting, the layer is facing upwards. It is strictly forbidden to drop the cut slag on the layer.

 

2. Groove processing and inspection

The form and size of the groove are designed according to the drawings, as not specified in the design. The principle of groove selection: to ensure that the welding quality is less filled with metal, the fusion ratio is small, and it is easy to operate. Groove processing is generally made by mechanical means. If the groove is opened by plasma cutting, gas cutting, etc., the oxide layer on the surface of the composite material must be removed. The finished groove shall be inspected for appearance without cracks and delamination, otherwise it shall be repaired.

 

3. Pre-weld cleaning

Surface cleaning is carried out using mechanical methods and organic solvents within 20 mm of the groove and its sides to remove oil, rust, metal chips, oxide film and other contaminants on the surface. Anti-splash paint should be applied within the range of 100mm from the bevel.

 

4. Weldment assembly

The assembly shall be based on the clad layer, and the amount of misalignment shall not be greater than one-half of the thickness of the clad layer and not more than 2 mm. For different thicknesses of the clad layer, the wrong margin shall be taken according to the thickness of the smaller clad layer. The tack welding shall be welded to the base metal base material and the same welding material as the welded base metal shall be used.

The welding of the accessories on the side of the clad layer shall comply with the requirements of the design drawings. When the design requires that the clad layer test accessories be welded to the base metal, the clad layer part shall be peeled off first, and the stainless steel bracket shall be welded to the base shell by the transition layer welding rod. The surface of the weld is welded by the same welding rod as the welded layer.