How to prevent exact pattern heat to deal with be out of shape problem mould heat treatment is out of shape

To a few accurate and mixed patterns, how to prevent exact pattern heat to deal with be out of shape problem mould heat treatment is out of shape is the mould deals with one of leading defect of the process. Often deal with to be out of shape and discard as useless because of heat, because this dominates essence of life of mixed pattern be out of shape become heat to deal with all the time the crucial question in production. The mould is when heat treatment, well-known. Quench especially in the process, because the mould is sectional departmental cent heats and of cooling rate abhorrent and the reason such as the when differring sex that the tissue of lukewarm together with that cause transforms, spend difference. Make a mould sectional each section volume bilges shrink inhomogenous, those who organize change is inhomogenous, cause what can cause a mould to be out of shape thereby. Constituent stress " the thermal stress that causes with place of difference in temperature of mould inside and outside. When mould of exceed of its internal stress succumb when the limit, decrease and control accurate and mixed pattern to be out of shape it is broad heat to deal with a of worker main research task. Will discuss decrease and control measure of metabolic of accurate and mixed pattern, the article tries accurate and mixed pattern to be out of shape state, be out of shape the research of the reason. In order to improve the quality of mould product and service life. One, the influence 　 1 of mould data. After the select material of the mould chooses T10A steeliness to build sectional dimension six to one, requirement to quench, be out of shape lesser mixedder pattern, some machinery plant deals with from select material and heat handy consideration. But the mould is out of shape bigger, hardness of the mould after hardness asks 56-60HRC heat deals with accords with technical requirement. Cannot use, cause a mould to discard as useless. The hardness after heat of this factory mould deals with later and deflection accord with a requirement. Use small be out of shape steel Cr12 steeliness is built. Should choose as far as possible small be out of shape steel, because this creates accurate and complex, demand,be out of shape lesser mould. Wait like steel of empty temper by dipping in water. 2. The influence mould with mould qualitative material contains round hole of ￠ 60m M, some factory delivers steel of a batch of Cr12MoV mixedder pattern. After mould heat treatment, occurrence ellipse of local mould round hole, cause a mould to discard as useless. Should not appear bigger be out of shape. Serious to be out of shape mould undertakes metallographic analyses discovery, generally speaking Cr12MoV steel is small be out of shape steel. Contain in mould steel and show banding distributing with lump. Have a large number of in all brilliant carbide. 1 mould is elliptical (be out of shape) the account that produce because certain way is shown in mould steel,this is of the existence carbide of the inhomogenous carbide that distributing when Peng heats, it prevents the aperture inside the mould to expand, bilge coefficient is smaller than the matrix organization of steel 30 ％ left and right sides. Systole of the aperture inside the mould is prevented again when refrigeration, make the aperture inside the mould makes the round hole of the mould appears elliptical. Happen to be out of shape inhomogenously. Should choose carbide to slant as far as possible the mould steel with lesser analyse, when ① of of 2 precautionary measures is creating accurate and mixed pattern. Do not pursue cheap, choose small steel mill to break carbide brilliant into pieces piece, manufacturing material is qualitative wronger steel products. ② slants badly to existence carbide the mould steel of analyse should undertake reasonable forging. Reduce carbide not to eliminate the anisotropy of function. ③ should undertake moving simple heat treatment to the mould steel after forge, the grade that distributings equably. Made acquisition carbide distributings even, fine the organization of body of all alone family name that can use Xiaohe dispersion, after reducing heat treatment of accurate and mixed pattern thereby be out of shape. ④ bigger to dimension or the mould that cannot forging. Make carbide is refined, distributing even, solid dissolve double refine processing. Circle of edges and corners is full change, can achieve reduce goal of metabolic of mould heat treatment 2, the influence that mould structure designs often is designed because of mould structure unreasonable, the material of some moulds select material and steel is qualitative very good. After if featheredge, pointed horn, groove, choppy step, thickness is dangerous,causing mould heat to deal with, be out of shape bigger. Different. 1 metabolic reason causes a mould when quench accordingly of the thermal stress between each place and constituent stress different, as a result of the mould everywhere bad distribution or existence acuteness round horn. Bring about the generation after making the mould quenchs to be out of shape. What each place bulk expands is different. 2 precautionary measures satisfy the situation that produces need actually to fall, when designing a pattern. Answer to reduce mould thickness wide gap as far as possible, structural asymmetry, the thickness boundary of the mould, obligate mental allowance, use smooth glide to cross as far as possible wait for a structure to design. According to the mould be out of shape the rule. After quenching, will not be out of shape because of the mould and make the mould discards as useless. To make the refrigeration when quenching even, to the pattern with particularly mixed appearance. Can use add up to a structure. 3, the influence of mould production working procedure and leftover stress a few appearance the mould with high demand of complex, precision, the factory often discovers. After heat deals with, be out of shape bigger, via the discovery after serious investigation, the mould deals with to did not undertake in machining and final heat any beforehand heat treatment. 1 after be out of shape the reason increased mould heat treatment be out of shape. The remaining stress in machining process and the stress overlay after quenching. 2 precautionary measures reduce the remaining stress after quenching. 3 use oily 170oC of temper by dipping in water to give oily air cold (classification quench) 　 　 4 use isotherm to quench craft can decrease quench leftover stress. The mould is out of shape lesser. The remaining stress after using above measure to be able to make the mould quenchs decreases. 4, heat deals with heat the influence 　 of craft 1 heat of the influence treatment craft of speed was opposite correctly after mould heat treatment be out of shape consider as refrigeration to cause commonly this is incorrect mould especially mixed pattern. Heat to a few moulds the contrast of craft can see apparently, of the mould be out of shape often produce bigger effect. Heat rate is rapidder, often happen bigger be out of shape. When heating as a result of steel, when any metals heat, 1 metabolic reason should expand. Same inside the mould, the temperature of departmental cent not all (because heat,form what heat namely thereby not all internal stress. The photograph of steel changes the dot is the following lukewarm inhomogenous) affirmative meeting causes the expand abhorrent sex of departmental cent inside the mould. Heat inhomogenously to basically produce thermal stress, spend. Exceed photograph changes temperature heats inhomogenous, return the sex when meeting those who produce constituent change differ, produce an organization to answer already the temperature difference of mould appearance and core is bigger, force. Because this heats,speed is jumped over fast. Stress is greater also, the mould heats up what after dealing with, arise to be out of shape bigger also. Generally speaking, 2 precautionary measures? Changing to mixed pattern when heating under the dot, answer slow heat. Mould vacuum heat deals with be out of shape should heat to be able to use warm-up to low-alloy steel mould than saline bath furnace (550-620oC quenchs beforehand to adding up to King Kong mould high to should be used 2 times small much. 2 heat the influence of temperature thinks to need to rise quench heat temperature. But manufacturing practice indicates, a few manufacturer achieve taller hardness to assure a mould. This kind of practice is impertinent is it is normal to use likewise heat undertake heating quenching below temperature, to mixed pattern. The heat after permission upper limit temperature heats deals with the heat that is out of shape the floor level temperature that should allow than be in heats deals with be out of shape get greatly much. Quench heat temperature is higher, 1 be out of shape the reason is well-known. The grain of steel jumps over hasten to be brought up, because bigger grain can make temper by dipping in water appears a gender to increase, make as a result of,quench mixed pattern mostly by in tall alloy steel is made, the stress of the generation when refrigeration is greater. Again. If quench temperature is high, nod because of Ms low, after mould heat is being increased to deal with in the organization, be out of shape. Rudimental austenite estimates increase. Choose floor level to quench as far as possible heat temperature, logical choice heats below the circumstance of the technical condition that 2 precautionary measures assure a mould temperature. Reduce sophisticated heat treatment in order to reduce refrigeration to be out of shape thereby. The stress when. 5, the influence of rudimental austenite is in like Cr12MoV steel mould quench and after microtherm temper, steel of mould of a few tall alloy. The length of the mould, wide, Gao Jiefa gives birth to contractible phenomenon, this is austenite of the remain after quenching because of the mould the quantity is overmuch and the 　 that cause 1 be out of shape all sorts of organizations in reason steel have compare volume differently, because of alloy steel (like Cr12MoV steel) many remain austenite is contained after quenching. Of austenite the smallest than bulk, this is mould of tall alloy steel quenchs the volume after microtherm temper happens contractible main reason. Of all sorts of organizations of steel decrease successively by following order than bulk: Martensite - body of family name of temper all alone - pearlite - austenite of remain of 2 precautionary measures measures austenite 　 bigger, 1 reduce appropriately quench temperature. Had narrated before no less than quench heat temperature is higher. Because this chooses to quench appropriately,heat the integral performance that should consider a pattern, temperature is the important step that reduces a mould to narrow. Fall in the circumstance that makes sure mould technology asks commonly. Reduce a mould to quench appropriately heat temperature. After Cr12MoV steel mould quenchs, 2 a few data make clear. 500oC temper relatively the rudimental austenite of 200oC temper is measured little half, be in so make sure the model should raise temper temperature appropriately. Manufacturing practice indicates: Deflection of mould of temper of 500oC of Cr12MoV steel mould is the smallest, below the premise that has technical demand. And hardness is reduced not much (2~3HRC also is to reduce a mould to be out of shape, cold treatment is being taken after the 3 patterns that dimension change produces when stability is used quench is the optimal craft that reduces rudimental austenite to measure. Because this nicety is complex,the mould should use deep cold treatment commonly. 6, the influence of cooling medium and cooling method but the influence in cooling process also is mould heat deals with be out of shape often is those who quench expression of the place after refrigeration comes out although this has above the influence of all sorts of elements. 1 be out of shape the reason steel that produce happens to change namely, when the mould refrigeration arrives when Ms dot is the following. Except the thermal stress with because refrigeration is abhorrent precocious place outside, still have because of the when differring sex that changes generation cooling rate is rapidder, constituent stress. Refrigeration is more inhomogenous, the stress that happen is greater, of the mould be out of shape bigger also. 2 precautionary measures are used as far as possible beforehand cold, below the 1 premise that makes sure mould hardness asks. To carbon steel and steel of low alloy mould but beforehand place of Leng Zhileng horn is nigrescent 720~760oC to transforming in pearlite the steel with area super-cooling stabler austenite is planted but beforehand cold control to 700oC. Reduce metabolic of a few mixed patterns effective method 2 use classification the thermal stress that refrigeration quenchs when can reducing a mould to quench significantly, arise and constituent stress. Use isotherm to quench can decrease significantly be out of shape. 3 pairs of a few accurate and mixed patterns. 7, improve heat treatment technology, reduce mould heat treatment to be out of shape adopt what method no matter, mould after quench be out of shape. Be out of shape is cannot prevent but mixed to should controlling the nicety of deflection strictly pattern can adopt the following method to undertake controlling. 1 use tone simple heat treatment and the accurate and mixed pattern with outside hardness higher demand, not tall to basic hardness requirement. After can adopting mould rough machining, undertake moving simple heat treatment, nonexistent matrix organization changes after finish machining, undertake microtherm nitrogen changes processing (500~550oC changes temperature as a result of mould nitrogen low. Furnace is additionally cold give heat to room temperature, cooling should the mould is out of shape lesser. Power is less also. 2 use beforehand demand of hardness of heat treatment if is not quite high, can use beforehand of heat treatment beforehand hard steel, to mould steel (be like 3Cr2Mo, to accurate and mixed pattern. 3CrMnNiMo steel) the hardness when be being used into made arrival (inferior hardness is 25~35HRC taller hardness is 40~50HRC to shape mould treatment next row beforehand heat treatment. CNC Milling