Analysis of crack causes in stainless steel sandwich pot
Why does the sandwich pot have cracks? What are the reasons? Let us look at the reasons for the electric heating sandwich pot analysis as follows:
In the manufacturing process of the stainless steel sandwich pot device, since the hemispherical head flap is cold-formed and formed, no residual stress is present in the flap without stress relief treatment, and the flap of the hemispherical head is in the welding process. Due to the limitation of the shape, the metal shrinks after the molten pool is cooled, and its outer shape is fixed and it is difficult to shrink with it, which results in the tensile stress perpendicular to the weld in the direction of the weld and the heat affected zone. .
During the welding process of the sandwich pot, the welding between the stainless steels in the pot is performed by manual arc welding. The welding rod adopts A102 and its composition is similar to 1Cr18Ni9TI. The composition is similar to the welding rod between 1Cr18Ni9TI stainless steel plates. The welding process is due to the base metal and fusion zone, and the heat influence. There is a large temperature gradient between the zone and the fusion zone; the stainless steel is sensitized and heated, and the diffusion rate of carbon to the intergranular boundary is faster than that of chromium and is folded at the intergranular boundary in the form of carbide (Cr23C6). Out, the amount of chromium in the folded carbide (Cr23C6) is much higher than the average content of chromium in the steel, so in the grain boundary and its adjacent areas (weld and heat affected zone) due to chromium carbide in the grain boundary The formation of aggregated precipitates produces a chromium-depleted zone along the grain boundaries.
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