The effect of Cu on performance in 304 stainless steel pipe

304 stainless steel pipe is 0Cr18Ni9 austenitic stainless steel pipe, is a very versatile 304 stainless steel tube, it is widely used in the production of good comprehensive performance (corrosion resistance and formability) of equipment and parts. The further study of 304 stainless steel is still a hot topic at home and abroad, of which the study and application of nickel are mostly manganese and nitrogen instead of nickel in stainless steel, and copper nickel is a new research direction. But at present, the research focus of domestic copper containing stainless steel is functional materials, focusing on the antibacterial properties of copper. However, there is very little research on improving the mechanical properties of copper. The creep deformation and fracture of copper containing stainless steel are studied abroad. The results show that copper is favorable for high temperature creep of stainless steel.

The action of copper on 304 stainless steel tubes is similar to that of nickel, that is, it can increase the corrosion resistance of stainless steel. Therefore, it is theoretically feasible to add some copper to reduce the content of nickel in stainless steel. In addition to adding copper to nickel solution of nickel in the supply and demand contradiction to a certain extent, 304 stainless steel tube, make full use of associated copper and nickel ore, reducing the cost of removing copper purification, with considerable economic benefits. However, the addition of copper can reduce the room temperature strength and plasticity of Cr Ni austenitic stainless steel, which can improve the cold forming property of stainless steel, but decrease its strength. On the premise of ensuring the original strength of the stainless steel, the plasticity of the stainless steel is increased by adding copper. This requires a certain heat treatment of copper containing stainless steel before use, the choice of the parameters in the process of heat treatment, heat treatment, microstructure of copper containing 304 stainless steel mechanical properties and corrosion resistance, try to get both strong hardness and good ductility of the new stainless steel materials.

3% Cu was added to the 304 stainless steel tube. It is found that there is no precipitate copper phase in stainless steel, and copper exists in the form of solid solution. With the increase of annealing temperature, the strength and hardness of stainless steel decrease gradually. Annealing at 800 * 3H is the best annealing process, and moderate hardness can be obtained. With the solid solution time shortened, the strength and hardness of stainless steel increased, and the plasticity of copper containing 304 stainless steel plate increased. The solid solution aging scheme of 1080 * 3min+800 * 2H * can obtain better comprehensive performance. After the solution treatment, the copper containing stainless steel has homogeneous microstructure and higher austenite content, showing better comprehensive properties and excellent corrosion resistance.

Source: China Steel Pipe Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)

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