Technology of bearing heat treatment reachs his to equip

The anneal equipment that anneal equipment shows level our country is oxidation furnace and coexistence of protective atmosphere furnace, oxidation furnace furnace of over protection atmosphere; Periodic furnace and successive furnace are concomitant, and periodic furnace over successive furnace. The country such as the United States, England, Japan is early in 20 centuries 669 time already popularized ball of isotherm of push rod type and roller bottom type to convert annealing furnace in the round, shorten anneal is periodic, managing the sources of energy, improve anneal quality. As the development of processing technique of bearing spare parts, and nicety forgings and accurate Zhan enlarge (cold Zhan) the adoption of craft, the treatment precision of part semifinished product is taller and taller, brought the demand to protective atmosphere anneal from this. Bearing industry should popularize protective atmosphere ball quickly to change anneal, in order to reduce the oxidation decarbonization after anneal, improve treatment efficiency, section material is energy-saving, reduce cost. 2.

The tool equipment that the tool equipment that groovy martensite quenchs shows martensite of convention of industry of bearing of level our country to quench is uneven, can divide the oxidation furnace that protects medium to not have from protective medium, can accuse atmosphere furnace and vacuum furnace. Take equipment of bearing heat treatment without the oxidation furnace that protects medium 25% the left and right sides, those who have protective medium is little take equipment of bearing heat treatment without oxidation furnace 50% the left and right sides, can accuse atmosphere furnace to occupy bearing heat treatment to equip 20% the left and right sides, vacuum furnace occupies bearing heat treatment to equip 5% the left and right sides. Can divide from manufacturing cycle for periodic furnace and successive furnace. Come nearly a few years, the tool equipment development that martensite quenchs basically centers in the following respects: (1) automation product line is current, the automatic product line that home introduces presses its structure (or the workpiece motion in furnace means) can divide for: Have Ma Fu net belt furnace, without Ma Fu the net takes net of furnace, casting catenary furnace, roller bottom furnace, platen furnace furnace and turn product line of bottom furnace series, expect on, before clean, protective atmosphere (may accuse atmosphere) next heating, quench, hind clean (still undertake the furnace end deep Leng Gun undertakes 2 times 2 times sometimes deep cold) reach temper to all be finished automatically. Degree of product line automation and control precision are tall, the quality of the workpiece after processing is even, the one part that product line of whole heat treatment can regard bearing as automatic product line is used. Diverse heat treatment product line applies to the heat treatment of the bearing spare parts of different type and dimension according to its structure characteristic, if the net takes furnace to apply to medium or small bearing ferrule; Turn bottom furnace applies to ferrule of small lot bearing; Roller bottom furnace deserves to have rise automatically fall quench device, apply to a wall thick larger bearing part; Platen furnace applies to scroll body and small-sized ferrule. (2) multi-purpose furnace can be in can accuse the cementite below atmosphere or carbolic nitrogen in all ooze, can quench below protective atmosphere again, of the workpiece that finish quench without oxidation process. It is a kind of periodic furnace, basically apply to the heat treatment of bearing spare parts of small lot, much breed. (3) the induction heats induction of equipment of temper by dipping in water, temper heats have heat speed is fast, energy-saving and be out of shape small wait for an advantage, the workpiece after processing has a few convention to heat the function that does not have. Our country shows application of level bearing heat treatment to basically be centered on rotary table bearing and car hub bearing, and do not have application basically on GCr15 steel. (4) the oxidation that heats to be able to decrease or shun work below condition of vacuum furnace vacuum, cooperate temper by dipping in water of tall calm sb's anger controallable the refrigeration of workpiece and be out of shape, the environment that avoided oily temper by dipping in water to bring pollutes a problem, realize clean heat treatment. Additional, after vacuum heat treatment, the microstructure of workpiece is more petty and even, the surface and core organization are consistent, hardness is even, be helpful for bearing exhaustion life rise. The heat treatment that vacuum furnace basically uses in special steel (heat temperature is in above of 1 000 ℃ ) with a few requirements of the bearing spare parts of taller GCr15 steeliness quench on, apply in domain of heat treatment of our country bearing wider. The development trend of vacuum furnace is freeboard calm sb's anger quenchs replace oil hardening, and apply vacuum cementite furnace to wait to be planted in order to solve new steel the application in bearing domain. (5) quench cooling medium and equipment quench medium can divide it is 3 kinds big: Oil radical, water radical and gas quench medium. Oil radical quenchs medium is the most commonly used quench medium. Common quenching oil is loss of whole system of N32 or N22 uses oil, cool to raise its function, fight aging behavior, shining function and divide into equal parts of high temperature capability to be not joined urge cryogen, clear lotion, brightening agent and antioxidant, formed fast oil, fast and shining oil and high temperature to classification the series quenching oil such as isothermal oil, of the bearing spare parts that asks with applying at different measurement to mix quench; Additional, still have low volatile vacuum quenching oil. Oil radical quenchs the defect of medium is to be in quench lampblack arises to cause air to pollute in the process, in subsequently water pollution is caused in cleaning a process. Water radical quenchs medium is the aqueous solution that comprises by organic polymer, corrosion inhibitor and other additive. Through the change the type of organic polymer is mixed chroma is attainable different refrigeration is characteristic, in order to agree with of different bearing spare parts quench refrigeration asks. In quench in cooling process, organic matter adheres to in spare parts surface, can reduce a spare parts to quench the dangerous sex of craze, and do not produce lampblack, clean convenient, free from contamination, it is to quench the development direction of medium. Gas quenchs is to use inert gase to be medium (commonly used nitrogen) , go to the nozzle eject that compresses gas to adopt special design workpiece surface, with realizing workpiece quench cooling. The structure that adopts the pressure that moves solar term style and nozzle can control refrigeration character and be out of shape. Gas quenchs compare water radical to quench cleaner, and cost is lower, its key technology is the structural design of nozzle. Our country gas quenchs in bearing the domain still is in start level, in the structure of nozzle design technology respect still has certain difference. Quenching refrigeration equips is to divide quench workpiece is affected to quench outside medium the another big factor of the effect. Our country shows level to quench cooling equipment controls parameter less, be opposite only commonly the loop of oily gentle oil undertakes controlling. Abroad executes multi-parameter to control to commonly used quenching oil chamfer, the direction that is like the cooling character with lukewarm, oily oil, oily loop and agitate, and the means that speed, workpiece enters oil, quench in order to get to first-rate organization and function, at the same time be out of shape reduce the minorrest rate. A few bearing manufacturer of our country also are trying multi-parameter control, the control that enters oily means through having work to conic bearing especially will solve bearing spare parts to quench the change of the angle in the process. Multitask quench press already applied in our country automatically, but automation degree cannot catch up with abroad. (6) rinsing equipment is cleaned is the necessary process after oily temper by dipping in water normally. The rinsing equipment that place of serial production line uses finishs gush of bubble of hot black leach, clear water to drench commonly wait for a process with sirocco drying, contain oily moisture to leave unit. In advanced rinsing equipment, still add before stoving have cooling unit 2 times (deserve to have refrigeration facility, temperature is between 10 ℃ of 5 ～ adjustable) , in order to reduce the content of rudimental austenite, increase the stability of dimension. Our country shows the rinsing equipment of level to basically use high pressure to clean fluid, this kind is cleaned to be illogical aperture and small oily channel disable, often cause temper lampblack much, pollution is big, still cause sometimes catch fire. Vacuum is cleaned is the rinsing equipment that in recent years development rises. The advantage of this kinds of rinsing equipment is: It is good to clean the effect, especially of complex to the structure part clean the effect more remarkable, surface of the workpiece after cleaning is shining; Safe, clean, clear lotion is clear water, do not add harmful to the environment chloride and oil kind solvent; Automation rate is high, and can use clean heat replace microtherm temper, save temper cost. In recent years, ultrasonic is cleaned, eddy current cleans the application on heat treatment the effect is very good also. 3.

The characteristic that isotherm of body of shellfish family name quenchs equipment is machined according to bearing, uses device basically has two kinds big: Automatic product line and periodic furnace. (1) the bearing with little, big batch suits breed of automatic product line automation production, if the production of railroad bearing uses automatic product line more. Automatic product line basically is mixed by protective atmosphere heating furnace composition of isothermal quenching tank, wait for place of Wen Cuihuo part to press the movement that carries work to be able to divide again with equipment among them it is 3 kinds: Turn bottom type, turn disk type and conveyer belt pattern. By love assist Lin Gong department develops turn bottom type, push disk type isotherm to quench equipment is turn bottom or push dish of orgnaization park isotherm in saline bath, workpiece presses certain metre pass in and out, memorial control goes out orderly makings, movement by PLC programme controll. Rate of automation of this kinds of equipment is high, but investment is large. (2) periodic type isotherm quenchs bearing of equipment rolling mill because breed much, batch is small, medium or small manufacturer of production of rolling mill bearing uses box type furnace or well type heat more + quench cooling chamfer + isothermal chamfer + clear washing trough, also have use box type heat + many isothermal chamfer. This configuration investment is little, applicability is strong, but labor strength is great, security is poor. Current, quench in isotherm of body of shellfish family name during be being popularized energetically, quench with isotherm of body of shellfish family name replace cementite steel to be used on the rolling mill bearing with lesser bear to get successfully already applied in our country. 4.

Protective atmosphere and control rise as what ask to quality of the surface after workpiece quenchs, protection (can accuse) atmosphere heats to gain ground more and more, the heat treatment that includes anneal inside all uses protection (may accuse) atmosphere heats. 20 centuries 70 time, basically use aura of mood of absorption of heat. Aura of mood of absorption of heat is raw material gas and airy gas mixture reaction of the part below the action in activator forms a kind to contain (CO) 18% ～ 23% , (H2) 37% ～ 42% , the protective atmosphere of surplus N2, this kind of atmosphere still has application in domain of heat treatment of our country bearing. Atmosphere of azotic radical propane applies on the front line of heat treatment oil in domain of our country bearing the widest, the group share of azotic methanol atmosphere and close of aura of mood of absorption of heat, with nitrogen - the nitrogen that methanol is a delegate base atmosphere applies on net belt furnace more. 90 time, appeared to put through air and hydrocarbon into prep above continuously the method yield gas inside 800 ℃ the chamber of a stove or furnace, give birth to mood aura continuously namely. Through considering to discover, this kind contains the atmosphere of tall CH4 composition, although its gas reacts short of is similar to the equilibrium rate of aura of mood of absorption of heat, but the transmission ability of its carbon or will control by the content of the CO in atmosphere and H2, with oxygen probe combinative CO2 analyzer undertakes carbolic situation is controlled can come true. The main good point of aura of straight unripe formula was to save raw material to enrage wastage in great quantities, according to statistic this is planted no matter atmosphere is used on furnace of periodic mood aura or successional atmosphere furnace, gas of its raw material uses up cost saving to all can be amounted to 70% the left and right sides. Today, the whole world has many 300 to cover atmosphere furnace to use this kind of atmosphere to undertake nitrogen of cementite, carbon about in all ooze and protective atmosphere quench wait for a variety of heat treatment. Aura of straight unripe formula applies in cementite domain more in domain of our country bearing. In last few years actual application makes clear, the service life of oxygen probe is bad and affirmatory, difference also cannot foreknow between the carbolic power that oxygen probe measures and real value. Accordingly, can accuse atmosphere sometimes because of the invalidation of oxygen probe cannot accuse, cause the defect such as decarbonization oxidation. Our country shows level to often use fixed desired result its measure precision, go against furnace implementation is full automatic change, can affect normal production even sometimes. In view of afore-mentioned reasons, abroad developed double survey a system, among them one takes standard oxygen probe to be used at normal control carbon power, another independence measures a system to be used at detecting the working state of this oxygen probe, namely the carbolic power that these two systems measure atmosphere respectively, appear when the result when very big error, can call the police. The 2nd measures systematic work component can be CO2 infra-red analyzer, also can be probe of oxygen of a miniature (λ , probe) . Up to now, already a lot of atmosphere furnace installed this to plant double survey a system. Whole of make a comprehensive view, technology of domestic bearing heat treatment and equipment relatively the developed country still has very large space, go up in anneal equipment especially difference is bigger. Technology of bearing heat treatment and equipment are otherer the industry also has certain space, raise what bearing quality matters to Chinese equipment manufacturing industry to revitalize. CNC Milling CNC Machining