The manufacturing process of stainless composite panels generally adopts hot rolling method, pouring method, explosion compounding and surfacing welding method. Among them, the stainless composite panels produced by hot rolling method are mostly used in the market. Stainless composite panels The base material generally uses low carbon steel and ordinary low alloy high-strength steel. The strength of the stainless steel composite plate is ensured through the base layer. The cladding material usually uses chromium-nickel corrosion-resistant stainless steel, and basically the thickness of the cladding accounts for the total thickness of the composite steel plate. 10-20% of thickness.

The welding process of stainless steel composite plates is the same as the welding process of a single material. First, from the welding sequence, the base weld must be welded first, and then the cladding welding seam must be welded. The interface between the base welding seam and the cladding welding seam must be isolated. The layer weld seam, while the isolation layer weld seam depends on the welding characteristics of the stainless steel composite plate, which can ensure that the plasticity of the welded joint of the composite steel plate and the corrosion resistance of the clad weld seam are good enough, while welding on the carbon steel weld seam When using stainless steel, there is also the problem of dilution of stainless steel welds by carbon steel welds. Because of the dilution effect, the chromium and nickel content in the stainless steel weld is reduced, and a hard and brittle martensite structure is easily formed in the stainless steel weld, thus reducing the plasticity and toughness of the welded joint. Therefore, the isolation layer weld gap must be Choose high-chromium-nickel duplex chromium-nickel stainless steel electrodes with good dilution resistance.

There are also some problems when welding stainless composite plates. One is that the cladding layer is easy to add carbon, which will destroy the corrosion resistance of the weld. The other is that the chromium and nickel alloy elements in the base layer will cause the joint to be brittle. Third, the transition layer is prone to form carbon-rich bands on the side of the cladding layer, and decarburization bands on the side of the base layer. They will destroy the corrosion resistance of the stainless steel composite plate and reduce the plasticity and toughness.

Let’s talk about the welding process of stainless steel composite panels. The first is cleaning and preparation before welding. The groove of the stainless steel cladding plate and the 15-20mm range on both sides need to be cleaned to prevent oil stains and splashes. The sides of the stainless steel groove should also be properly protected to prevent scratches and scratches caused by welding. splash.

In order to ensure the welding quality of the cladding, isolation layer and base welds of the stainless steel composite plate and control the weld size of the isolation layer, it is necessary to select the appropriate groove form and size, and ensure that the processing accuracy of the groove size meets the process requirements. .

The third point is assembly and fixing. Assembly must be carried out before welding. First, ensure the assembly gap. Usually the butt gap is about 2 mm, and strictly control the misalignment. If the misalignment is too large, it will directly affect the isolation layer and composite The actual production results show that the misalignment of stainless steel should not be greater than 0.5 mm, and this can be controlled in production.

The fourth point is the welding sequence. First, base welding should be done from the base layer, and after each layer is fully welded, the welding root should be removed from the cladding side. In order to ensure the slot size, angular welding is generally used. After grinding with a grinder, the groove depth is 3-4 mm, which is most suitable. After passing the X-ray flaw detection, the isolation layer and cladding welds can be welded.

In terms of process measures, the isolation layer welding seam needs to cover the base layer welding seam and exceed the boundary line of the base layer and the cladding layer by 1 mm. The welding seam switch should be kept smooth to prevent the welding seam from bulging. Otherwise, it should be smoothed with a grinding wheel and then re-welded. For layer welds, it is necessary to carefully clean up the spatter of carbon steel electrodes that fall on the clad groove surface. Welding stainless steel composite plates requires three different electrodes to avoid the wrong use of electrodes, so as to ensure that the quality of the welds is up to standard.