What preparations do stainless steel clad plates need to make before welding?

　　Stainless steel clad plate is a kind of high-efficiency and energy-saving material of two metals, which uses carbon steel as the matrix and continuously covers 0.1-20mm stainless steel on one or both sides. The welding at the junction of the base layer and the clad layer of the stainless clad steel plate belongs to dissimilar steel welding, and its weldability mainly depends on the physical properties, chemical composition, joint form and filler metal type of the base layer and clad layer. So what preparations do stainless steel clad panels need to make before welding?

　　1. Cutting

　　The cutting and groove processing of stainless steel composite plates should be done mechanically as much as possible, and the cutting surface should be smooth. Plasma cutting can also be used. When cutting, the composite layer faces upwards, and it is strictly forbidden to drop the cutting slag on the composite layer.

　　2. Groove processing and inspection

　　(1) The form and size of the groove shall be specified in the design of the drawings. If the design is not clearly specified, it can be selected with reference to Figure 1-1.

　　Welding process of stainless clad steel plate

　　(2) The principle of groove selection: to ensure welding quality, less filler metal, small fusion ratio, and easy operation.

　　(3) Groove processing is generally made by mechanical methods. If the groove is made by plasma cutting, gas cutting and other methods, the oxide layer on the surface of the composite material must be removed.

　　(4) The finished groove should be inspected for appearance, and there must be no cracks and layers, otherwise it should be repaired.

　　3. Cleaning before welding

　　Surface cleaning shall be carried out by mechanical methods and organic solvents within 20mm of the groove and both sides to remove oil, rust, metal chips, oxide film and other dirt on the surface, and anti-splash paint shall be applied within 100mm of the double layer from the groove .

　　4. Weldment assembly

　　(1) The assembly should be based on the composite layer, and the amount of misalignment shall not be greater than half of the thickness of the composite layer, and shall not be greater than 2mm. When the thickness of the composite layer is different, the amount of misalignment shall be taken according to the smaller thickness of the composite layer.

　　(2) The tack welding shall be welded on the base metal, and the same welding material as that of the base metal shall be used. Refer to Table 1-3 for manual arc welding tack welding seams (δ0 is the thickness of the base layer).

　　(3) During the assembly process, the fixtures should be welded on the double layer carefully, and the fixtures should be welded on the side of the base layer.

　　(4) The welding of the accessories on the side of the multi-layer should meet the requirements of the design drawings. When the design requires that the accessories on the side of the multi-layer be welded on the metal of the base layer, the part of the multi-layer should be peeled off first, and the stainless steel bracket should be welded to the base layer with a transition layer electrode On the shell, the surface of the weld seam is welded with the same electrode as the cladding layer.