1. The effect of mechanical polishing. For the mechanic […]
1. The effect of mechanical polishing. For the mechanical polishing of austenitic nickel-chromium stainless steel, such as 1Cr18ni95Ti, the abrasive only flattens the surface under the action of large directional pressure. Therefore, the surface has a certain plastic deformation structure characteristic - fiber structure, ie, Bayer layer.
2. The effect of electrochemical polishing. Ma Shengli et al. studied the surface structure of 1Cr18ni95Ti stainless steel after electrochemical polishing in phosphoric acid/sulfuric acid electrolyte from a typical fibrous structure to a uniform and dense granular grain structure. This is obviously related to the mechanism of the polishing process.
Usually when the current passes through the electrolyte, the stainless steel is on the anode, and the microscopic protrusion on the metal surface is preferentially dissolved, and the microscopic dissolution speed of different crystal faces in the crystal grains is also different, resulting in the appearance of grain edges. However, the microstructure of the surface is very different under different electrochemical polishing conditions. For example, in an electrolyte of 65% (wt) water, when the anode current density is 30 A/dm 2 and t is 70 ° C for 15 min, a better surface polishing effect can be obtained. When the anode current density (DA) is too low (DA<20A/dm2= or too large (DA<40A/dm2), or too high (>90°C) or too low (<50°C=), or polishing time Long (>25min) or too short (<10min) are not conducive to the improvement of surface polishing quality.