Preparation before rust prevention. Although the forgings have been cleaned and cleaned after heat treatment, the surface of the forgings should be cleaned again before rust prevention treatment. Because in the forging turnover process, the surface of the forging will be contaminated by oil (because of the transfer of the box often have oil). For precision forgings, operators in the hand handling, will also be hand sweat on the forging table, these surface pollution must be completely eliminated before rust prevention.
The preparation work at this stage is exactly the same as the surface cleaning process mentioned above and will not be repeated.
Antirust oil antirust, the use of antirust oil antirust, grease or resin substances as the main body, then add oil soluble corrosion inhibitor composed of temporary antirust coating, its antirust effect is mainly shown in the following aspects.
The dispersed corrosion inhibitor molecules in the oil film can be directionally adsorbed on the metal and oil surface to form a multi-molecule interface film, which has a shielding effect on corrosion factors. The antirust oil has hydrophobicity and can stabilize the displaced water in the oil.
Can improve the oil film to metal absorption, increase resistance, reduce activity. It can inhibit the formation of corrosion cells and prevent atmospheric rust.
In the antirust operation, the antirust oil usually adopts the cold coating method, and the antirust grease usually adopts the hot coating method. When hot dip coating is used, the temperature should be reduced as far as possible to increase the thickness of the oil film, and the anti-rust effect can be greatly improved with plastic film packaging.
The choice of antirust oil, according to the different mechanical processing process, the antirust after heat treatment can be the temporary antirust between the process, can also be the final antirust of the finished product, the two requirements are different, the selection of antirust oil is not the same.
When choosing the anti-rust oil between the processes, the forgings should be considered in the process of processing and turnover with the operator's hand contact, easy to produce fingerprinting rust on the surface of the forgings, at this time, the best choice of replacement type anti-rust oil. Its quality requirements should meet SH/T0692-2000 No. 4 displacement type antirust oil standard. Among its performance indexes, human sweat replacement and human sweat washing are the key points.
Sometimes because the forgings can not be timely turnover, need to overlap in the middle warehouse storage, but also to avoid overlapping surface rust or overprinting, especially cast iron products. The length of anti-rust period of finished products stored in the factory should be considered, whether the products are overstocked in the factory or can be sold in time, whether they are directly used at the user's place or need long-term storage and other factors. The commonly used antirust oils for finished product storage include solvent dilution antirust oil, lube type antirust oil, lipid type antirust oil and gas phase antirust oil, etc. The quality shall meet the standard of SH/T0692-2000.