Stainless steel seamless pipe inner wall polishing

With the continuous improvement of material and cultural living standards, society's demand for stainless steel seamless pipes is increasing, and higher requirements are also put forward for the polishing of stainless steel pipes. As a result, the stainless steel pipe polishing production line (stainless steel pipe polishing machine) came into being. This article will describe the polishing process for the inner wall of stainless steel seamless pipes.

1. The round tube polishing machine is mainly composed of a loading device, a polishing host, and a unloading device. A speed-regulating motor links the three parts of the polishing machine for synchronous transmission of raw materials. The polishing host consists of six groups of polishing heads, each group is driven by a three-phase motor. The stainless steel welded pipe polishing machine consists of a loading device, a polishing host, and a unloading device. The polishing main machine is driven by a speed-regulating motor to realize raw material transmission. The polishing main machine consists of four sets of flat polishing mechanisms and four sets of side polishing mechanisms.

2. Stainless steel welded pipes use emery cloth wheels for rough polishing and semi-finish polishing, and PVA grinding wheels for fine polishing. The surface roughness Ra value can reach 0.1~0.05μm. For coarse polishing of stainless steel welded pipes, an abrasive cloth wheel is used, and for fine polishing, a cloth wheel coated with chromium oxide polishing paste is used for polishing. The surface roughness Ra value after polishing can reach 0.1μm.

3. In terms of polishing stainless steel round tubes and square and rectangular tubes, some small businesses also use simple stainless steel tube polishing machines (single-group polishing machines). Repeated replacement of grinding wheels and multiple operations to meet technical requirements. Small-diameter stainless steel round pipes are polished with a single grinding head. The equipment is similar to a centerless grinder, and PVA grinding wheels and emery cloth wheels can be used. The particle size of the sand should be fine grinding sand above No. 180.

4. Small-diameter stainless steel welded pipes are produced continuously online. The thicker the wall thickness, the greater the investment in the unit and welding equipment, and the less economical and practical it is. The thinner the wall thickness, its input-output ratio will decrease accordingly; secondly, the process of the product determines its advantages and disadvantages. Generally, welded steel pipes have high precision, uniform wall thickness, and high brightness inside and outside the pipe (steel pipes are determined by the surface grade of the steel plate) Surface brightness), can be arbitrarily fixed length.

In addition, seamless pipe polishing techniques are mainly divided into two types, one is chemical polishing and the other is electrolytic polishing.

1. Seamless steel pipe chemical polishing

This method is commonly used in the surface treatment process of seamless steel pipes. It does not require DC power supply and special fixtures. It can polish parts with complex shapes and has high productivity. Chemical polishing can obtain a surface with physical and chemical cleanliness, and can also remove the mechanical damage layer and stress layer on the surface of seamless steel pipes to obtain a mechanically clean surface, which is beneficial to preventing local corrosion of parts, improving mechanical strength, and extending the use of parts. life.

Because there are many varieties of seamless steel pipes and different grades of seamless steel pipes have different corrosion laws, there are many types of chemical polishing solutions for seamless steel pipes. The basic components include corrosives, oxidants and water. Corrosion is the main component. If the seamless steel pipe is dissolved in the solution, polishing cannot be performed. Oxidants and additives inhibit the process and move the reaction in a direction that favors polishing. Water regulates the concentration of the solution and facilitates the diffusion of reaction products.

2. Seamless steel pipe electrolytic polishing

This method is to hang the seamless steel pipe products on the anode and perform anodic electrolytic processing in the electrolytic polishing solution. During electrolytic polishing, the surface of seamless steel pipe products undergoes two contradictory processes at the same time, namely the continuous generation and dissolution of the oxide film on the metal surface. Due to different current density distributions, the surface of the product continuously forms and dissolves at different rates. The surface of the anode is undergoing two opposite processes at the same time, film formation and dissolution. The continuous generation and dissolution of the passivation film smoothes the surface of the seamless steel pipe products to achieve a highly smooth and glossy appearance, which satisfies the surface requirements of the seamless steel pipe products. Polishing and finishing purposes.

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