AP: Acid Pickling. Use acidic solutions such as nitric acid and fluorous acid to remove the oxide layer of the steel pipe. Cheap and fast, but it is easy to cause grain boundary corrosion, and the inner and outer surfaces are rough and easy to have suspended impurities attached.

MP: Mechanical polishing. The brightness and effect of the oxide layer, holes, and scratches commonly used on the steel pipe surface depend on the type of processing method. In addition, although mechanical polishing is more beautiful, it will also reduce corrosion resistance, so it needs to be passivated when used in a corrosive environment. Moreover, there are often polishing material residues on the surface of steel pipes.

BA: Bright Annealing. During the drawing process, the steel pipe must be lubricated with grease and the crystal grains will be deformed due to processing. To avoid this grease remaining in the steel pipe, in addition to cleaning the steel pipe, you can also use high temperature to eliminate deformation during high-temperature annealing, use argon as the atmosphere in the furnace, and further clean the steel pipe by combusting argon with carbon and oxygen on the surface of the steel pipe. The surface produces a bright effect, so this method of using pure argon annealing heating and rapid cooling to brighten the smooth surface is called brilliant annealing, although using this method to brighten the surface can ensure that the steel pipe is fully clean and free from any external pollution. However, if the brightness of this surface is compared with other polishing methods such as mechanical, chemical, and electrolytic, it will feel like a matte surface. Of course, its effect is also related to the content of argon and the number of times of heating.

ValueAnnealingBright AnnealingFunctionReduce Internal Stresses and Increase DuctilitySimilar Objectives, but With a Surface Quality FocusAtmosphereTypically, Vacuum or AirControlled Environment to Avoid OxidationCostLowerHigherProcess StepsGradual Cooling After HeatingRapid Cooling After Heating in a Non-oxidizing EnvironmentSurface FinishMay Cause Oxidation and Poor Finish.Creates a Glossy, Bright Surface.ApplicationsMetalworking and General ManufacturingHigh-performance Applications.