Release time : 2015-06-10 07:18:20
When purchasing bearings, it is necessary to choose right materials. Firstly, you must be familiar with features of materials so that you can choose and use bearings well. Here to introduce common bearing materials. I am confident that you will benefit from it through brief understanding.
It should be chrome steel which people are familiar with. Chrome steel is the most common material and also called high carbon chromium steel with about 1% carbon and 0.5% to 1.65% chrome. Chrome steel can be divided into six categories including high carbon chromium bearing steel, bearing steel without chrome, carburizing bearing steel, stainless bearing steel, medium and high temperature bearing steel and antimagnetic bearing steel. The most common material used for bearings is high carbon chromium steel, that is, GCr15. It refers to the steel whose mass fraction of carbon is less than 2.11% and does not contain any alloying elements. Sometimes it is called plain carbon steel or carbon steel. Although the cost of carbon steel is low, the chrome steel has replaced carbon steel in the market. Because chrome steel is better in the rotation speed, noise, life and loads. When demands are low, you can choose carbon steel which saves a lot of costs.
With the upsurge of chrome steel, stainless steel is already emerging. It has higher demands in hardness and rotation speed. Here are types and properties of stainless steel. The stainless steel can be classified in: 420, 440, 304 and 316. These are common materials. The chemical formula of 420 stainless bearing is 4Cr13. It contains 12% to 14% chrome and 1.35% to 0.5% carbon. The chemical formula of 440 stainless bearing is 9Cr18. It contains 16% to 18% chrome. The chemical formula of 304 stainless bearing is 18Cr-Ni, which has good corrosion resistance, heat resistance, and mechanical strength in low temperature. Its punching and bending are good during hot-working process and it has good hardening phenomena without heat treatment process. The chemical formula of 316 stainless bearing is 18Cr-12Ni-2.5Mo. It has good corrosion resistance, atmospheric corrosion resistance and high temperature strength. It can be used in strict conditions with good work hardening ability and is non-magnetic.
The 440 stainless steel is relatively better than the 420 stainless steel. It is a kind of stainless iron. The advantages of it are cheap price, high hardness, high loads and rotation speed. The disadvantages are that rust resistance corrosion resistances are not very well. The 316 stainless steel can be said to be the pure stainless steel. Though it has good corrosion resistance and also can be used in non-magnetic environment, it can't be hardened as a whole. Therefore, the 316 stainless steel is not suitable for big loads and high rotation speed. The corrosion resistance of 304 is better that of 316, but the corrosion protection capability of 304 is far better than that of 440. 304 can be fully used in the sea or in the acidic and alkaline water.