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Bearing heat treatment technology and equip ‘ Two)

31st July 2013 Bearing Technology 1 Comment

2.Frock apparatus that the regular martensite quenches

The frock apparatus that the Chinese bearing trade regular martensite quenches at the present stage is different, can be divided into the oxidation furnace, controlled atmosphere furnace and vacuum furnace of the unprotected medium protecting mediums. About 25% that the oxidation furnace of the unprotected medium accounts for the heat treatment of the bearing and equips, ones that protect the medium do not have about 50% that oxidation furnace accounts for the heat treatment of the bearing and equips fewer, about 20% that the controlled atmosphere furnace accounts for the heat treatment of the bearing and equips, about 5% that the vacuum furnace accounts for the heat treatment of the bearing and equips. It can be divided into cycle that from production cycle the stove and serial stove.

In near these decades, the frock apparatus development that the martensite has quenched has mainly concentrated on the following several respect:

1The automatic production line is at present, the automatic production line which China adopts, according to its structure or the mode of motion in the stove of work piece Can be divided into: There are horse’s not net belt stoves, not have horse’s not net belt stove, cast chain stove, roller bottom stove, cylinder stove net belt stove and transfer to the serial production lines of bottom stove, material loading, the previous washing, controlled atmosphere or controllable atmosphere It play it heat, it quench, after if you can’t wash, last deep freezings two-shot roller bottom stoves cryogenics two-shot also sometimes And automatically finish. Automaticity and control accuracy of production line are high, the quality of the work piece is even after dealing with, the heat treatment production line of whole can serve as a collinear part of automatic production of the bearing. Different heat treatment production lines are suitable for the heat treatment of different type and bearing part of the size according to its structural features, if the net belt stove is suitable for the medium and small-scale bearing ring; Transfer to the bottom stove and suitable for the bearing ring of short run; The roller bottom stove is furnished with the quench unit of the automatic rising, is suitable for the bearing part with bigger wall thickness; The cylinder stove is suitable for rolling elements and small-scale collars.

2The multi-purpose stove can make cementation or carbonitriding in the controlled atmosphere, can quench under the controlled atmosphere, finish not oxidizing and quenching the technological process of the work piece. It is a kind of cycle stove, mainly suitable for the bearing part heat treatment of short run, many varieties.

3Induct heating quench and back fire the intersection of apparatus and induct heating have the intersection of heating and the intersection of speed and fast, energy-conservation and advantage such as being out of shape and little, the treated work piece has some to heat the unexistent characteristic conventionally. The heat treatment of the bearing employs and mainly concentrates on bearing and car hub bearing of the rotary table at the present stage in China, basically there is no application on GCr15 steel.

4Can reduce or avoid oxidation of the work piece to heat under the state of vacuum of the vacuum furnace, can control the cooling of the work piece and deform, has avoided the problem of environmental pollution brought in oil quenching while cooperating with high-pressure air quenching, realize and clean the heat treatment. In addition, after vacuum heat treatment, the microstructure of the work piece is tinier and even, the surface keeps the same with core organization, the hardness is even, are favorable to the improvement of fatigue life of the bearing. The vacuum furnace is mainly applied to the heat treatment heating temperature of the special steel in 1 Over 000 ℃ And at some the intersection of requirement and higher the intersection of GCr15 and steel the intersection of bearing and part quench, employ relatively wide in the field of Chinese bearing heat treatment. The development trend of the vacuum furnace is that the vltrahigh voltage is angry to quench and replace oil hardening, and employ vaccum carburizing furnace,etc. in order to solve the application in the field of bearing of the new steel grade.

5Quenching cooling medium and equipment quenching medium can be divided into three major kinds: Oil base, water base and gas quenching medium. The quenching medium of oil base is the most frequently used quenching medium. Ordinary quenching oil is that N32 or N22 complete system loss uses the oil, characteristic, ageing resistance, bright characteristic and high temperature behavior,etc. add and urge refrigerant, cleaning agent, brightening agent and antioxidant respectively for improve cooling its, grade serial quenching oil such as isothermal oil after forming fast oil, fast bright stock and high temperature, in order to apply to the quenching of different size and bearing part of the requirement; In addition, there is low and volatile vaccum quenching oil. It causes the air pollution that the shortcoming of the quenching medium of oil base produces the soot in the course of quenching, cause the water pollution in subsequent washing.

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