Recently, there is customer feedback: Acid rust remover reacts with Anti-rust Oil, is there a better rust remover instead? Background: The factory makes fuel tanks and hydraulic oil tanks for construction machinery such as excavators; Process: phosphoric acid pickling + phosphating Problem: After phosphating, use phosphoric acid + plant acid mixed rust remover to remove rust, and apply rust preventive oil after rust removal; after coating and baking, the rust remover and rust preventive oil react to produce some black flakes. Is there a better alternative to rust remover?
First of all, the possible reasons for rust residue on the surface after pickling and phosphating are as follows: ①The grains of the phosphating film are too coarse or too fine, which reduces the corrosion resistance; ②The content of free acid is too high; ③The surface of the workpiece is too corroded; ④The content of phosphate in the solution is insufficient; ⑤There is residual acid on the surface of the workpiece; ⑥Phosphating tank There are too many precipitations and the nozzles have been blocked; ⑦The processing temperature is low; ⑧The reasons for the equipment, such as the spraying pressure is too large, the direction of the nozzles, etc. The existing pickling solution can be appropriately changed, and environmentally friendly pickling products can be selected. Secondly, the currently used rust remover and rust preventive oil may be incompatible, and the acidic chemical properties of the rust remover can easily lead to the qualitative change of the rust preventive oil under the action of high temperature baking, and the two chemicals A certain chemical reaction will take place. Furthermore, no matter what kind of rust remover and anti-rust oil it is, it needs to be cleaned before rust prevention, so as to ensure that the rust remover will not react with the anti-rust oil. Improve: ①After rust removal, industrial cleaning and rinsing should be carried out. The rust remover on the surface can be cleaned with a degradable and environmentally friendly metal cleaning agent, followed by rinsing to clean the residual cleaning agent and surface dirt. This will not affect the subsequent use of anti-rust oil. ②After cleaning and rinsing, the rust-proof surface needs to be dried and cooled (to the rust-proof temperature requirements suitable for rust-proof oil). ③ After the anti-rust oil is applied, it is necessary to ensure the uniformity and dryness of the surface, and avoid greasy surfaces, otherwise it will be contaminated with other pollutants, resulting in poor anti-rust effect. ④It is best to cooperate with the cleaning agents mentioned above, and use the anti-rust oil that has passed the compatibility test for anti-rust treatment, so as to avoid chemical reactions between the rust remover, cleaning agent and anti-rust oil. ⑤If you want to replace the rust remover, there are organic acid rust remover and neutral rust remover to consider: organic acid rust remover can not only replace the traditional pickling solution for rust removal, but also can be used as a direct rust remover. It is a relatively environmentally friendly water-based rust remover; neutral rust remover is an environmentally friendly water-based rust remover that does not harm metal substrates and human skin. ⑥ For the above operations of rust removal, cleaning, rinsing, and rust prevention, ensure that the operator wears clean and tidy gloves to prevent the acidic hand sweat of the human body from contaminating the metal surface and affecting the use effect of cleaning and rust-proof products. The above is a brief analysis of the possible reasons and possible improvement methods. The specific improvement of rust removal, cleaning, rust prevention and other processes needs to be carried out according to the actual production situation and rust prevention requirements.
