When the stainless steel plate is welded or the like, it is easy to make the stainless steel plate bend the crack first if it is improperly operated. At this time to repair the stainless steel plate welding cracks, you can use the grinding wheel grinding machine to eliminate cracks, reduce the cracks in the hardening edge, and then carry out penetration testing, and confirm the crack elimination. Can also determine the depth of the crack after the corresponding electrode to do the repair, such as stainless steel electrode, carbon steel electrode, electric isolation layer and other materials.
321 stainless steel plate’s surface crack phenomenon and treatment methods
As 321 stainless steel plate high toughness, good fatigue resistance, easy welding, it is widely used in hardware, shipbuilding, aerospace, machinery and other fields. 321 stainless steel plate plate is used without torsion rolling method, stainless steel surface clean and smooth, high dimensional accuracy.
321 stainless steel plate plate in the production process because of the process and other reasons will be prone to crack. There are three types of cracks, first in the direction of rolling into a straight or jagged crack; followed by cracks containing inclusions; there are cracks at the subcutaneous bubble exposure and oxidation.
The first type of crack is generally because the inclusions are not processed to produce cracks, so in the rolling, it is necessary to clean up the inclusions in the stainless steel water.
The second type of crack is generally caused by cracks in the stainless steel plate surface. The stainless steel plate is folded during the rolling process, and the surface of the round bar exhibits a straight or jagged crack along the rolling direction. The solution is to use the appropriate deoxidation alloying process to control the oxygen content of molten steel, the inclusions in the molten steel should also be cleaned.
The main reason for the formation of the third subcutaneous bubble is that the molten steel contains a large amount of gas. When the molten steel solidifies, the gas is discharged and the bubbles in the outer layer of the slab form subcutaneous bubbles, arranged in a honeycomb vertical arrangement, After the welding can not form a crack. So in the production to take full protection to protect the pouring process to prevent the secondary oxidation of molten steel to reduce the bubble generation, improve the slab purity.
Cracking of stainless steel plate after stretching and its treatment
Now stainless steel processing production is more commonly used is ferritic stainless steel and austenitic stainless steel. After the completion of processing, according to the degree of different tensile processing, there may be cracking phenomenon. Austenitic stainless steel delayed cracking is generally determined by the performance of stainless steel itself.
In order to prevent the overall annealing of stainless steel tensile deformation, only the mouth of the annealing, such as high-frequency annealing. Ferritic stainless steel products do not undergo phase change after stretching, cracks are usually caused by the residual stress, it must be carried out annealing.
Can be appropriate to use the lubricant, in the concave and convex form between the formation of tough film, which is conducive to the tensile molding of stainless steel. In addition, when the tensile deformation of the larger tensile parts, can also use the polyvinyl fluoride film as a lubricant, because it is characterized by high tear strength, and the lubrication effect is good, you can effectively stainless steel plate and Mold surface isolation.
In addition, you can also use white cast iron to do crimping ring mold, the use of its storage performance, the formation of lubricating oil film. But also the use of cone-shaped blank holder, the edge of the workpiece processing smooth, remove the gap, but also to effectively avoid cracking.
Source: China Stainless Steel Plate Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)