Rust--metal corrosion has caused huge losses to mechanical manufacturing, especially precision parts such as bearing products, which cause rust, which not only affects accuracy and surface roughness, but also reduces service life, even scrapped and cannot be used. .
Bearing anti-rust work is an important task, especially the rust prevention between processes, like the bearing in the heat treatment workshop after pickling, cleaning, grinding, there are many processes. When the product is not produced by running water, it is stored in the intermediate tank once it is processed sequentially, so the bearing rings stored between the processes must be rust-proof.
Traditional rust prevention methods and their deficiencies
There are several methods for rust prevention between
bearing processes:
1. Dip in the rustproof tank
The bearing ring is immersed in an aqueous solution of 5% sodium nitrite and 0.6% sodium carbonate. The anti-rust effect is good, but many rust-proof tanks and other equipment occupy a large amount of space, and management is not convenient.
2. Dip coating of concentrated sodium nitrite solution
After washing the product, it is immersed in a solution containing 15%-20% sodium nitrite and 0.6% sodium carbonate, and then stacked. In this way, the rust-preventing period is short, generally only 7-14 days, and in the rainy season, due to the wet weather, it can only last 2-3 days.
It has to be reprocessed and it takes labor and money.
3. Oiling
Apply anti-rust oil like finished product. This method must be cleaned before the next step is performed, which is troublesome.
Introduction of new anti-rust technology
After working with relevant manufacturers, many years of production practice has shown that the rust prevention between processes has been improved several times, so that the rust-proof effect is better. Initially, the rust prevention of the roller was tested. The semi-finished product and the finished product were washed once a day with an aqueous solution of sodium nitrite. After 3 months, no rust was found in the test results. Now, the semi-finished product of the
bearing ring is spray-proof and rust-proof, and the effect is also the same. The spray-type anti-rust process is relatively simple, and the method is as follows:
1. Purchase and construction of equipment
According to how much semi-finished products are stored, an intermediate warehouse is built. The ground floor is made of cement floor, and a walkway can be set in the middle, about 1.5m, which is used to pass the bearing ring. Place a pool of sodium nitrite solution at the end of the channel. The solution is formulated with 5%-10% sodium nitrite plus 0.6% sodium carbonate, and the backwater groove is made on the ground, and then the bearing rings are stacked on both sides of the floor. Above, there is a 0.6m walkway between each pile of bearing rings. It can be said that the intermediate library is designed to be about 64m2, and its sodium nitrite aqueous solution pool is 1m3.
2. Process method
Each morning, it is rinsed with an aqueous solution of sodium nitrite. The aqueous solution is sucked from the pool by a water pump, and is passed through the rubber pipe to the shower head to rinse the bearing ring like a shower. The rinsed aqueous solution flows back to the pool from the backwater ditch, and is placed on the upper layer of the backwater tank at the end of the backwater ditch. A fine wire mesh and gauze are used as a filter to scatter the dust and dirt into the pool. The intermediate library should be clean and in good condition.
The solution in the pool is tested every 2 days and supplemented according to the test results. The replacement period of the solution in the pool is carried out according to different months. It is completely changed every 2 weeks from April to September, and every month from October to March.
in conclusion
The spray-type rust-proof, easy to manage, and save labor, in the past, the intermediate library with 2 people can not complete the rust prevention, and now one person can also do other work, from the rust-proof effect is also very significant. In March 2003, more than 4,000 rolls of 7002136 and 3620 were sprayed and rust-proof. For nearly a year, they have remained very bright and have no rust. In addition, there is a great saving in the consumption of chemicals. In the past, the roller workshop consumed more than 4,000 kilograms of sodium nitrite per month, but now only 200 kilograms is used, saving nearly half.
The spray-type rust-proof method has been tested and used by relevant manufacturers in recent years, which proves to be suitable for medium and large-sized, long-volume, long-cycle bearing semi-finished products.
