Bearing steel new technology and direction

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Bearing steel basically is used at making the scroll body of scroll bearing and ferrule. Because bearing should have sex of macrobian life, high accuracy, small calorific amount, high speed, Gao Gang the character such as gender, low noise, tall wearability, because this asks bearing steel should have: Intensity of exhaustion of tall hardness, even hardness, tall stretch limit, tall contact, must tenacity, certain temper by dipping in water appears a gender, the corrosion resistance in atmospheric lubricant can. To achieve afore-mentioned performance demands, granuality of content of uniformity, metalloid to the chemical composition of bearing steel field trash and type, carbide and distributing, the requirement such as decarbonization is strict. Bearing steel on the whole to high quality, high-powered develop with much breed direction. Bearing reachs applied environment to differentiate by character with steel for: Steel of steel of tall carbon chromic bearing, cementite bearing steel, high temperature bearing, do not become rusty bearing steel and material of bearing of appropriative special type. To get used to high temperature, high speed, high load capacity, be able to bear or endure corrode, refuse radiant demand, need develops a series of new-style bearing steel that have special property. To reduce the oxygen content of bearing steel, developed the smelt technology of the bearing steel such as remelting of broken bits of vacuum smelt, report, electron beam remelting. And the smelt of steel of big batch bearing by fusion of electric arc furnace, development imposes the fine outside furnace into furnace of the refine at the beginning of all sorts of types. Current, use a capacity to be more than ＋ of Lian Zhu of VD of ／ of LF of ＋ of furnace of 60 tons of Chu Lian or RH ＋ to connect make friends craft to produce bearing steel, in order to achieve the goal of high quality, efficient, feebleminded bad news. In respect of heat treatment craft, develop to be able to accuse heat treatment of atmosphere annealing furnace continuously by furnace of car bottom type, bell furnace. Current, successive heat treatment furnace the longest for 150m, the ball that processes manufacturing bearing steel changes an organization stability and even, decarburized layer is small, disappear energy consumption is low. 20 centuries since 70 time, as economy development and technology progress, the applied limits of bearing expands; And the development of international trade, the development that promoted internationalization of bearing steel standard and new technology, new technology and new equipment again and application, efficiency the technology of form a complete set with tall, low cost mixes tall, quality tooling emerge as the times require. Japan and Germany all built nobleness to be spent completely, the bearing steel product line of high quality, make the crop mushroom of steel, the quality of steel and fatigue life rise substantially. The oxygen content of Japan and the bearing steel that Sweden produces falls 10ppm is the following. 80 time evening, japanese hill this world is special the advanced level of steel company is 5.

4ppm, reached the level of steel of vacuum remelting bearing. The contacts fatigue life to be organized to steel uniformity of bearing is very sensitive. Raise clean to be spent completely (the foreign matter element in reducing steel and) of field trash content, the metalloid field trash in making steel and carbide are petty and even distributing, can improve the osculatory exhaustion life of bearing steel. The organization below bearing steel use condition should be temper martensite there is petty carbide grain equably on matrix, such organization can gift the property that bearing steel place needs. The main alloying element in steel of tall carbon bearing has carbon, chromic, silicon, manganese, vanadium to wait. How obtaining a ball to change an organization is the serious problem in bearing steel production, accuse make friends cold the significant production technology that is advanced bearing steel. Through charging make friends or press hard against each other hind quick cold pass the time in a leisurely way besides meshy carbide, acquire right preliminary organization, can shorten bearing steel ball spends annealing time, refine carbide, improve fatigue life. In recent years, russia and Japan use microtherm to charge press hard against each other (850 ℃ of 800 ℃ ～ are the following) , use after make friends air is cold add short time anneal, or cancel a ball completely to change anneal technology, with respect to the bearing steel organization of attainable qualification. The 650 ℃ Wen Jia of bearing steel is versed in also is new-style technology. Before eutectoid steel or high-carbon steel hot-working if have,fine grain can be formed in treatment process, be in (0.

4 ～ 0.

Inside limits of 6) fused temperature, below certain strain rate, present plasticity of favorable balance of trade. American naval academy (NSP) undertook to 52100 steel 650 ℃ Wen Jia is versed in the experiment makes clear, true below 650 ℃ meet an emergency 2.

5 do not happen rupture. Accordingly, replace high temperature to machine likely with 650 ℃ lukewarm treatment and change anneal craft union to rise with the ball, it is this equipment and working procedure, managing to simplifying the sources of energy, important to raise quality to have meaning. In heat treatment respect, raising a ball to change anneal quality, obtain petty, even, globose carbide and shorten annealing time or the research respect that cancel a ball to change anneal process had progress, namely wire rod production uses constituent anneal twice, the 730 ℃ of 720 ℃ ～ drawing hind recrystallization anneal instead the constituent anneal of 760 ℃ . It is good to can get low, ball changes hardness so, the organization that does not have meshy carbide, the key should make sure intermediate drawing decreases 14 ％ of rate ≥ . This craft makes the efficiency of heat treatment furnace raises 25 ％ ～ 30 ％ . Continuous the development direction that the ball changes technology of anneal heat treatment is bearing steel heat treatment. Each national capital is studying and develop new-style bearing steel, enlarge application and the bearing steel that replace a tradition. Be like steel of fast cementite bearing, will raise cementite rate through changing chemical class status, among them carbolic content by 0 traditional.

08 ％ ～ 0.

20 ％ rise 0.

45 ％ are controlled, cementite time is shortened by 7 hours. Developed high frequency quench bearing steel, use common medium carbon steel or in carbolic manganese, chromium steel, connect exorbitant frequency to heat quench will replace common bearing steel, simplified to produced working procedure to reduce cost again already, improved service life. Fatigue life of the GCr465 that Japan develops, SCM465 compares SUJ, 2 tall 2 ～ 4 times. Because be in high temperature, corrode, lubricant condition uses bearing below harsh environment more and more, the bearing steel such as the M50(CrMo4V) that used in the past, 440C(9Cr18Mo) already cannot satisfy use requirement, be badly in need of developing processability low, fatigue life grows can good, cost, the bearing that can suit different goal and utility uses steel, if high temperature cementite is steel M50NiL, easy,treatment does not become rusty bearing steel 5018M and material of bearing of pottery and porcelain. Appear the weak point with low sex in the light of GCr15SiMn steel temper by dipping in water, our country developed high temper by dipping in water to appear gender and GCr15SiMo of steel of bearing of rigid of temper by dipping in water, ≥ of HRC of rigid of its temper by dipping in water 60, temper by dipping in water appears 25mm of sexual J60 ≥ . The L10 of osculatory exhaustion life of GCr15SiMo and L50 rise than GCr15SiMn respectively 73 ％ and 68 ％ , below same use condition, double the service life of the bearing that makes with G015SiMo steel is GCr15SiMo steel. In recent years, our country still was developed can managing the sources of energy, resource conservation and fight steel of percussive GCr4 bearing. Compare with GCr15 photograph, the concussion value of GCr4 increased 66 ％ ～ 104 ％ , rupture tenacity raised 67 ％ , contacted fatigue life L10 to raise 12 ％ . GCr4 steel bearing uses high temperature to heat, the surface quenchs heat treatment craft. The photograph of GCr15 steel bearing that shows with complete temper by dipping in water is compared, the life of GCr4 steel bearing rises apparently, can use at bearing of train of burden high speed. Bearing steel basically will be spent completely to nobleness henceforth and two way develop function diversification. Those who raise bearing steel is clean degree, reduce the oxygen content in steel especially, can prolong the life of bearing apparently. Oxygen content reduces 5ppm by 28ppm, fatigue life can extend an amount form. To prolong the life of bearing steel, people devotes oneself to technology of development application fine to reduce the oxygen content in steel all the time for years. Pass indefatigable effort, the lowermost oxygen content in bearing steel already the 5ppm that from 20 centuries the 28ppm of 60 time reduces 90 time. Current, our country is OK the lowermost oxygen content in bearing steel control is in 10ppm left and right sides. Bearing uses environmental change to ask bearing steel must have the diversification of function. Be like device rotate speed rise, need allows high temperature to use (200 ℃ are the following) bearing steel (use normally the Si content, method that adds V and Nb rises to achieve the purpose) that fights bate and stable measure on the foundation of SUJ2 steel; Corrode applied circumstance, need development does not become rusty bearing steel; Be versed in to simplify art, should develop high frequency quench bearing steel is mixed short when cementite bearing steel; To satisfy the need of aerospace, should develop steel of high temperature bearing. CNC Milling CNC Machining