The material of the slewing bearing directly determines the performance and service life of the bearing. At present, the main structure of the bearing on the market is mostly made of bearing steel, which has the characteristics of corrosion resistance and stability. Of course, in addition to bearing steel, there are also metal materials such as aluminum alloy or copper. In addition, the sealing ring and cage of the bearing may be different from the material of the bearing body. The following slewing bearing manufacturers will share what materials are good for the slewing bearing.
What material is good for the slewing bearing
1. Ring and rolling element material
In the early stage, 45# steel was used for the slewing bearing, which was gradually eliminated in the later stage due to poor modulation performance. At present, in the more common processing technology, the rolling elements of the slewing bearing are made of carbon-chromium bearing steel which is hardened as a whole. The grade is made of GCr15 or GCr15SiMn steel; the ring of the slewing bearing is made of surface hardened steel, and is made of 50Mn steel if there is no special requirement. But sometimes customers also choose to customize other grades such as 42CrMo, 40Cr, etc. The following introduces the characteristics of these grades of steel.
(1) 42CrMo is a high carbon steel with good quenching and tempering properties and quenching properties, and is an ideal material for slewing bearings.
(2) 50Mn has good hardenability and is also an excellent choice for slewing bearings.
(3) 40Cr is also good in terms of mechanical properties, and is still in the stage of exploration and practice.
(4) GCr15 small slewing bearing can be selected, but milling and drilling in the process are troublesome due to full quenching, so it is generally not recommended.
2. Cage material
Cages for slewing bearings have integral, segmented, spacer block and other structural forms. The types of cage materials are: mild steel stainless steel cage, bakelite/plastic (nylon) cage, brass/bronze/aluminum alloy cage, etc. The spacer block type is made of polyamide 1010 resin, ZL102 cast aluminum alloy, etc. .
The characteristics of bearing cages of various materials are as follows:
(1) Steel bearing cage: It is often made of 08 and 10 carbon steel sheets by cold stamping. Commonly used steel cage materials are 20, 30, 45, 0Cr18Ni9, 1Cr18Ni9Ti, 40CrNiMo, ML15, ML20, etc., which are commonly used in bearing cages, with solid and durable performance.
(2) Non-ferrous metal bearing cage: different from steel, non-ferrous metal has its special properties. For example, aluminum alloy has the characteristics of low density, good thermal conductivity and good corrosion resistance; copper alloy has good thermal conductivity, small friction coefficient, It has the characteristics of good formability and high operating temperature; zinc-aluminum alloy has the advantages of low cost, low density and excellent performance.
(3) Non-metallic cage: Non-metallic cage materials mainly include polymers and their composite materials, including nylon, phenolic tape, PTFE, etc. The polymer material has good strength and elasticity matching, which can effectively reduce the heating and wear of the bearing.
3. Sealing ring material
The materials used for bearing seals are generally commonly used sealing materials, mainly including: nitrile rubber, silicone rubber, fluorine rubber, EPDM rubber, fluorobutadiene rubber, PTFE, polyurethane rubber, acrylic rubber, Anaerobic glue, etc.
The material of the sealing ring of the slewing bearing is made of oil-resistant rubber or NBR rubber. Hydrogenated nitrile rubber has better oil resistance than nitrile rubber, but if you are not too demanding on oil resistance, use nitrile rubber, because hydrogenated nitrile rubber is relatively expensive. Nitrile rubber also has a certain acid and alkali resistance. However, if the requirements for oil resistance and acid and alkali resistance are higher, silica gel should be selected, but its price is higher.
How to choose the material of the slewing bearing
The editor analyzes the materials used in the slewing bearing under the premise of the current production technology level of the slewing bearing.
1. Rolling body material: The rolling body is generally made of GCr15SiMn.
2. Ring material: 50Mn is used for the slewing bearing ring, but sometimes 42CrMo is used to meet the needs of the host in special applications.
3. Cage material: There are different types of cages such as integral type, segment type, isolation block type and so on. The integral or segmented retainer is made of 20# steel or ZL102 cast aluminum alloy. The spacer block retainer adopts polyamide 1010 resin, ZL102 cast aluminum alloy or QA110-3-1.5 aluminum bronze.
4. Sealing ring material: Oil-resistant rubber, fluorine-containing rubber, oil-resistant nitrile rubber sealing ring should be selected for the slewing bearing. The clearance of the slewing bearing is mainly used to compensate the manufacturing error and installation error of the slewing bearing supporting parts and the relevant host assembly parts to ensure the normal use of the bearing. According to the structure type/tolerance class of the slewing bearing and the pitch circle diameter of the rolling element group, the clearance value or the pre-interference of the slewing bearing.
The above is the introduction of the slewing bearing manufacturer on what material is good for the slewing bearing. The bearing materials mentioned by the editor of Longda are suitable for the slewing bearing, but the specific use environment and performance requirements may have different requirements for the bearing material. , please choose according to the actual situation.