Machined Parts don't rust thanks to rust prevention oil! So how do we choose? How to use it?

2021/07/20



What is rust preventive oil?
Rust often refers to the corrosion of ferrous metals in the air, caused by the electrochemical effect caused by the participation of water and oxygen. Rust preventive oil mainly uses the rust inhibitor to form a protective film on the metal surface to isolate water and oxygen and thus play a role in rust prevention.

Classification of common antirust oil for mechanical parts processing
1、Thin layer rust prevention oil
Thin film, low dosage, forming a thin anti-rust film on the surface of the workpiece, does not affect the appearance of the product, good cleaning, good anti-rust performance, suitable for automotive, hardware and electronic industry parts between the process of anti-rust and sealing anti-rust.
2、Replacement type antirust oil
With dehydration performance, it is suitable for products that are not completely dried after workpiece cleaning, and can replace water out, so that it can be cleaned well afterwards, and is commonly used for inter-process rust prevention and sealing rust prevention.
3、Hard film antirust oil
It has excellent antirust performance in humid and salt spray environment, and is generally used in shipping and ship hull, steam chassis and equipment, etc. where the environment is harsh and the antirust performance is high.
4、Water-based antirust agent
It is widely used for rust prevention between processes of ferrous metal, alloy steel and non-ferrous metal products with short anti-rust period.
About the selection of antirust oil
1、Choose according to the product material.
Different metal materials have different requirements for rust prevention oil, such as cast iron and copper, which have different requirements for rust prevention.
2、Choose according to the period of rust prevention.
For short-term rust prevention, you can use rust prevention oil with less viscosity and thinner oil film, while for longer period rust prevention, you need rust prevention oil with more viscosity and thicker oil film.
3、Choose according to the structure and usage of the product.
For example, for smaller products, you can use immersion antirust, and for larger products with more complex structures, you can use spraying or brushing to prevent rust, regardless of which method is used, you should ensure that an effective antirust film is formed in each part to avoid local rusting (attention should also be paid to the operator's hand to avoid direct contact with the metal surface, as human sweat contains rust-causing substances such as chloride ions and lactic acid, which can easily form handprint-like rust on the workpiece). (human sweat contains chlorine ions, lactic acid and other rust-causing substances, which can easily form handprint rust on the surface of the workpiece).
4、Select according to the subsequent processing and assembly requirements.
Such as the later processing technology, storage environment, packaging conditions and whether cleaning is needed before assembly.
The use method and precautions of rust prevention oil
1、Soaking method: The advantage is that it can form a uniform antirust film on the surface to ensure complete coverage of the product, and the cost is low.
2、Spraying method: It is suitable for large and complex structured products, high performance sprayer must be used, and it is easy for the products to fail to form the antirust film completely, and the working environment requires good ventilation performance when using it.
3、Brush method: This method is simple to use, but it is necessary to ensure that every position of the workpiece is brushed to, and the brush must be kept clean before use.
4、Rinsing method: High efficiency, recycling, can save cost, but need to drain the product in the tank regularly as well as replace it regularly to avoid too much moisture and other substances affecting the rust prevention effect.
The above points are some basic knowledge about the selection and use of antirust oil. In the production process, it is still easy to use antirust oil and still have rust. The common reasons are: too much moisture on the surface of the workpiece, the workpiece fails to form an antirust film, the antirust oil has not been replaced for a long time and a lot of moisture and dust remain in the oil, the antirust film on the surface of the workpiece is not fully formed and is packed in the package. Moisture condensation caused by temperature difference makes rusting more serious, packaging material or quality does not meet process requirements, etc.