The perfect appearance of the part illustrates Xavier's mastery of metal finishing.
Stainless Steel CNC Machined Parts Passivation & Electrolytic Polishing
Stainless steel passivation principle
Passivation is a method of slowing down the corrosion rate of metal by transforming the metal surface into a state that is not easily oxidized. Metal due to the role of the medium generated corrosion products if a dense structure, the formation of a thin film, tightly covered in the surface of the metal, changing the surface state of the metal, so that the electrode potential of the metal greatly to the positive direction of the leap, and become corrosion-resistant passivation, and show corrosion resistance of precious metals performance, this film is called passivation film.
Stainless steel electrolytic polishing principle
Stainless steel electrolytic polishing is mainly for stainless steel workpiece surface brightening treatment.
To be thrown workpiece for the anode, insoluble metal for the cathode, the two poles at the same time immersed in the electrolytic tank, through the direct current and produce selective anodic dissolution, the surface of the workpiece is gradually flattened, so as to achieve the effect of the workpiece to increase the brightness of the surface.
Stainless steel nitric acid passivation type
Types | Solution (% by volume) | Solution temperature (°C) | Minimum immersion time (min) | |
Nitric oxide 1 | 20%-25% nitric acid and 2.5% ± 0.5% sodium dichromate (non-environmentally friendly) | 50-55 | 20 | √ |
Nitric oxide 2 | 20%-45% nitric acid | 20-30 | 30 | √ |
Nitric oxide 3 | 20-25% Nitric acid | 50-60 | 20 | √ |
Nitric oxide 4 | 45%-55% Nitric acid | 50-55 | 30 | √ |
Stainless steel citric acid passivation type
类型 | 溶液（体积%） | Solution temperature (°C) | Minimum immersion time (min) | |
Citric1 | 4%-10% citric acid | 60-71 | 4 | √ |
Citric 2/ | 4%-10% citric acid | 49-60 | 10 | √ |
Citric 3 | 4%-10%柠檬酸 | 20-49 | 20 | √ |
Xavier Stainless Steel Passivation & Electropolishing Capabilities
Environmentally friendly: only nitric acid 1 passivation is non-environmentally friendly, the rest of the types are environmentally friendly
Type | Nitric acid passivation, citric acid passivation | Electrolytic polishing |
substrates | Stainless Steel Series | 300 Series Stainless Steel |
standard | ASTM A967 | GB/T 20016 |
Maximum processing size(cm) | 100*45*80 | 100*45*80 |
Maximum weight per piece (kg) | 80 | 50 |
color | natural color | bright white |
Test Methods | Boiling water test, wet cloth test, temperature test, immersion test, salt spray test, copper sulfate test, | Size inspection, appearance inspection |
Roughness change of stainless steel electrolytic polishing
Before electrolytic polishing: roughness distribution is 1.0-3.0 um.
After electrolytic polishing: the roughness distribution is within 0.3 um.
After electrolytic polishing the size will only reduce, the reduction range is certain, the appearance of roughness of the product size will deviate from the better 10um below, the roughness of the product size will deviate from the larger tens of um.
CNC machined parts passivation & electrolytic polishing cases
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Special requirements for passivation - sandblasting
Xavier has mature sandblasting and anti-sandblasting processes and technical capabilities to implement whole or partial sandblasting plating on the same product with steel parts, stainless steel, aluminum alloys, copper alloys, zinc alloys, etc. as the base material.
Sandblasting process is to use compressed air as a driving force, in order to form a high-speed jet beam will be sand abrasive high-speed jet to the surface of the workpiece that needs to be treated, so that the surface of the workpiece changes. Due to the impact and cutting effect of the abrasive on the surface of the workpiece, the surface of the workpiece obtains a certain degree of cleanliness and different roughness, so that the mechanical properties of the surface of the workpiece can be improved, so as to improve the fatigue resistance of the workpiece, increase the adhesion between it and the coating, and prolong the durability of the coating, as well as facilitating the leveling of the coatings and the decoration.
Local anti-sandblasting refers to the same product for the precise size of the parts or need to local special decorative parts do not need sandblasting, and take the method of shielding so that it is not sandblasted process, to provide solutions for the local anti-sandblast protection.