316L stainless steel pipe surface divided into AP grade, MP grade, BA grade, EP grade? Is there a difference?

[guidebook] : In addition to brand, material origin and production and processing technology, a key factor that directly affects the price of 316L stainless steel pipe is the surface treatment method. In order to be able to further improve the characteristics of 316L stainless steel pipe, processing pipe internal and external surface specific...

In addition to brand, material origin and production and processing technology, a key factor that directly affects the price of 316L stainless steel pipe is the surface treatment method. In order to be able to further improve the characteristics of 316L stainless steel pipe, processing pipe internal and external surface specific methods are divided into several: acid pickling passivation (AP), mechanical polishing (MP), bright annealing (BA) and electrolytic polishing (EP) treatment process. According to experimental data and practical indications, 316L stainless steel tube roughness is reduced, surface adsorption is weakened. In this case, what is the difference between AP grade, MP grade, BA grade, EP grade stainless steel tube? Please refer to the following content:

AP (Acid Pickling) Acid Pickling Treatment

The corrosion resistance of stainless steel mainly comes from the chromium contained in its chemical reaction with oxygen to form a dense oxide film on its surface. The role of the pickling process is to allow it to advance this reaction to improve the corrosion resistance of 316L stainless steel pipe. Pickling process, will completely remove the attached to the surface of the 316L stainless steel pipe oil stains and dirt and production of some of the substances contaminated. The inner and outer surfaces of the pipe are rough, and it is easy to attach suspended impurity residues.

AP grade stainless steel pipe

BA (Bright Annealing) bright annealing

Polishing wheel or polishing belt with the help of abrasives in the polishing agent on the surface of 316L stainless steel pipe grinding and polishing production processing, thus promoting the 316L stainless steel pipe surface to achieve a flat and smooth polishing effect. Its brightness depends on the type of processing technology. In addition, mechanical polishing is more beautiful but also reduces corrosion resistance, so when used in corrosive environments need to be passivated, and 316L stainless steel tube surface often has polishing material residue.

BA grade stainless steel tube

MP (Mechanical polishing) mechanical polishing

316L stainless steel tube in the production process, used to lubricate the grease grain may be deformed due to production and processing, in order to avoid as much as possible grease residue in the 316L stainless steel tube, in the annealing process, the reasonable use of high temperature to argon as the atmosphere in the furnace, by argon and 316L stainless steel tube on the surface of the combination of carbon and oxygen combustion, and further cleaning of the surface of the 316L stainless steel tube to form a bright effect, the use of pure argon gas annealing process, the use of pure argon gas annealing process. This use of pure argon annealing heating and rapid cooling to brighten the surface of the way called bright annealing. Although this way to brighten the surface can keep 316L stainless steel tube clean without any foreign pollution. But the brightness of this surface with other polishing methods compared to mechanical, chemical, electrolytic will have a foggy feeling. Of course, its effect is also related to the content of argon gas and the number of heating.

MP grade stainless steel tube

EP (Electro Polishing) electrolytic polishing

Electrolytic polishing is the use of anode treatment, according to the principle of electrochemistry, properly adjust the voltage, current, acid composition, and polishing time, not only can make the surface to achieve bright, smooth, clean effect, but also can enhance the corrosion resistance of the surface, so it is a very good brightening the surface of the method, of course, its cost and technology will be improved a lot.