A New Anti-rust Process for Precision Bearings between Processes

Rust-the corrosion of metal, has brought huge losses to machinery manufacturing, especially the corrosion of precision parts such as bearing products, which not only affects the accuracy and surface roughness, but also reduces the service life, even scrapped and can not be used.

Bearing rust prevention is an important work, especially the rust prevention between processes. For example, there are many processes for bearing after pickling, cleaning and grinding in heat treatment workshop. When the product is not produced by assembly line, it will be stored in the intermediate warehouse after one-time sequential processing, so the bearing rings stored between processes must be rustproof.

Traditional rust prevention methods and their shortcomings

The following methods are generally used for rust prevention between bearing processes:

1. Immerse in the rust-proof tank

Immersing the bearing ring in the aqueous solution of 5% sodium nitrite and 0.6% sodium carbonate has a good antirust effect, but it takes up a lot of space and is inconvenient to manage.

2. Dip-coating concentrated sodium nitrite solution

After cleaning the product, immerse it in a solution containing 15%-20% sodium nitrite and 0.6% sodium carbonate, and then pile it up. Using this method, the rust prevention period is short, which can only last for 7-14 days, and it can only last for 2-3 days in the rainy season because of the humid weather.

It must be reprocessed, which requires labor and money.

Step 3 oil

Apply antirust oil like a finished product. This method must be cleaned before the next process, which is troublesome.

Introduction of new anti-rust process

After working together with relevant manufacturers to tackle key problems, many years of production practice shows that the rust prevention between processes has been improved many times, and the spray-type rust prevention effect is better. Initially, roller rust prevention was tried. Semi-finished products and finished products were washed once a day with sodium nitrite solution. After 3 months, no rust was found in the sampling results. Now, semi-finished products of bearing rings are treated with spray rust prevention, and the effect is the same. The spray antirust process is relatively simple, and its method is as follows:

1. Purchase and construction of equipment

According to how much semi-finished products are stored, an intermediate warehouse is established, the ground is made of cement floor, and a walkway, about 1.5m, can be set in the middle to pass the car with bearing rings. At the end of the passage, put a water pool for storing sodium nitrite aqueous solution, and the solution formula is 5%-10% sodium nitrite and 0.6% sodium carbonate, and make a drainage ditch on the ground, and then pile bearing rings on the floors on both sides, leaving a 0.6m walkway between each pile of bearing rings. It can be said that the design of the intermediate warehouse is about 64m2, and the pool of sodium nitrite solution is 1m3.

2. Process method

Rinse with sodium nitrite aqueous solution once every morning. The aqueous solution is sucked out of the pool by the water pump, passed through the rubber pipe to the shower head, and washed the bearing ring like spray. The washed aqueous solution flows back to the pool from the backwater ditch. On the upper layer of the pool at the end of the backwater ditch, a filter screen is made of fine barbed wire and gauze to make the textile dust and dirt flow into the pool. The intermediate warehouse should be clean with good quality.

The solution in the pool is tested every two days, and supplemented according to the test results. The replacement period of the solution in the pool is carried out in different months, once every two weeks from April to September, and once a month from October to March of the following year.

conclusion

Spray rust prevention is more convenient to manage and saves labor. In the past, rust prevention in the intermediate warehouse could not be completed with two people. Now, one person can also do other work, and the rust prevention effect is also remarkable. In March, 2003, more than 4000 rollers of 7002136 and 3620 were sprayed for rust prevention, which remained very bright for nearly a year without rust. In addition, the consumption of chemicals is also greatly saved. In the past, roller workshops used to consume more than 4,000 kilograms of sodium nitrite every month, but now they only use 200 kilograms, saving nearly half.

The spray anti-rust method has been tested and used by relevant manufacturers in recent years, which proves that it is very suitable for medium and large-scale bearing semi-finished products with many batches and long cycle.