Spare parts of turning powder metallurgy

Use pulverous metallurgy (P/M) craft makes the part that is used at car motivation to fasten application be in grow continuously. The component that makes with P/M craft has a lot of important and distinct advantages. The leftover and poriferous structure that keeps intentionally in these spare partses to self-lubricating have profit with sound insulation. Use P/M technology can produce the complex alloy that makes very difficult or impossibly with conventional foundry technology. The treatment capacity of the part that makes with such technology is done not have even rarely normally, this makes them cheaper and waste in data side fewer. But unfortunate is to be in these spare parts character are trade they machine the backside of appeal hard. Although one of original intention of P/M industry are to eliminate all treatment, but this target has not been achieved. Most spare parts is ' adjacent and final figure ' , need some kind of precision work certainly. Compare with cast and forging photograph however, a few material from the purify on P/M spare parts are typical wear-resisting. Cutting tool life suffers the harm of poriferous structure, and poriferous structure is one of character that make P/M spare parts has all sorts of wide application. Poriferous structure can oil storage and sound insulation, but also arise microcosmic the interrupted cutting that go up. Should go to suffer concussion continuously to the point of a knife when solid grain reciprocating translation from aperture. What this can bring about body of very small fatigue broken fission and edge cutting blade is petty cut bits. Worse is, grain normally extremely hard. The macroscopical hardness that although measure,arrives is spent in Rockwell 20~35 between, but the grain that forms a part is individual can be as high as Rockwell 60 degrees. These hard grain bring about serious and fast point to wear away. Spare parts of a lot of P/M is but of heat treatment. They are harder after heat treatment stronger. Finally, as a result of agglomeration and heat treatment technology and use gas, the surface can be contained hard and the oxide of wear-resisting and / or carbide. The major function of the P/M part that function includes machinability inside is become with alloy chemistry not only cent relevant and the level with poriferous structure is relevant. A lot of construction parts contain aperture rate to amount to 15%~20% . Use as filter the rate containing aperture of the spare parts of device may be as high as 50% . In the other one aspect of the matter of series, forging or spare parts of HIP(thermionic Die Casting) contains aperture to lead 1% or fewer. This latter material is becoming particularly important in car and plane application, because they achieve higher intensity level. The tensile strength of P/M alloy, tenacity and extend a gender as density can increase. Perhaps be with the other place, machinability also rose. Because,this is porous have harm effect to point of a knife. The addition of level of the rate that contain aperture improves the sound insulation performance of the spare parts. The damp oscillation with standard general spare parts decreases in P/M spare parts. Blowpipe of this pair of machine tools, air conditioning and pneumatic tool are very main. The rate that contain aperture is opposite high self-lubricating gear also is necessary. Although P/M industry is ceaseless,machine difficulty one of developing targets are to eliminate machine treatment, and a of P/M craft main attraction is to need only a few treatment, but a lot of spare partses still need an aftertreatment to obtain precision or better appearance is bright and clean degree. Unfortunate is treatment these spare partses are extremely difficult. The most trouble that encounter is by porous cause. Porous the microcosmic exhaustion that brings about point. Cutting blade is being cut cut, it is mixed from grain pass between Kong Zhi. Reduplicative little impact causes the small break on generation cutting blade. These fatigue crackle growth till cutting blade small collapse. This kind of small collapse normally very petty, normally expression wears away for normal abrasive. Porous the thermal conductivity sex that still reduces P/M hardware. Its are the temperature on cutting blade as a result can cause very high crescent moon wears away depression and be out of shape. The poriferous structure that interior is linked together provides cutting juice the access from cutting area eduction. This meeting causes hot crack or be out of shape, getting cut in especially important. The exterior area that internal poriferous composition causes increases to still allow to happen when heat treatment oxidation and / or carbonization. The elephant mentions before in that way, these oxide and carbide are very hard very wear-resisting. Poriferous structure also gives out the invalidation of reading of spare parts hardness this are all in all. When the macroscopical hardness that goes measuring part of a P/M of purpose, it contains the element of the hardness of aperture. Poriferous structure causes structural collapse, reach the erroneous impression of opposite weaker part. Grain is individual want a lot of harder. Describe above the elephant, distinction is dramatic. The existence of the field trash in pulverous metallurgy spare parts also is adverse. In treatment, these grain can be pulled from the surface, when it from outdated is brushed to be in before cutting tool spare parts apparently form abrade or nick. These field trash normally very big, visible hole leaves in spare parts surface. What the irregular of carbolic content brings about machinability is abhorrent. For example, content of FC0208 alloy carbon is in 0.

6% to 0.

9% between. A batch of quantities that contain carbon 0.

The material of 9% is opposite harder, cause difference of cutting tool life.

And another batch of quantities that contain carbon 0.

The material of 6% gets wonderful cutting tool life.

Two kinds of alloy are in limit. Final treatment question and the cutting type that produce on P/M spare parts are relevant. Because the spare parts is close to final figure, cut normally deep very shallow. This needs free cutting blade. The tumour accumulating bits on cutting blade often causes small collapse. Processing technique to overcome these problems, use a few technologies (it is distinctive) to this industry. The surface is poriferous the structure often is closed through dip ooze. Need add and free cutting normally. Latter, had used a design to be used increase powder clean the pulverous production technology of the improvement of the oxide when spend and reducing heat treatment and carbide. Close the surface is poriferous structure by the metal (it is copper normally) or polymer dip ooze is finished. Once guessed the action of dip ooze resembles lubricant, voluminous experimental data shows real good point depends on shutting the face poriferous structure and from this and the prevents cutting blade microcosmic exhaustion that come. Brace up quiver reduce improve cutting tool life and appearance bright and clean degree. Life of the cutting tool when ooze shows the most dramatic use dip to close when poriferous structure rises 200% . The accretion such as the MnS of such as, S, MoS2, MgSiO3 and BN is foregone can improve cutting tool life. These accretion depart through making cut bits to go up more easily from workpiece, break bits, prevent the tumour that accumulate bits and lubricant cutting blade to raise machinability. The amount that increases accretion rises machinability but reduce intensity and tenacity. Control agglomeration and the pulverous pulverization technology that heat treatment furnace enrages cause the production of cleaner powder and spare parts. This makes the happening of field trash and exterior oxide carbide the smallest change. Cutting tool material most using the cutting tool at P/M industry widely is those are producing good appearance bright and clean degree of wear-resisting below the condition, be able to bear or endure point burst and the material that do not produce the tumor that accumulate bits. And these character are useful to any treatment operations, when they are machining P/M spare parts especially important. Include the cutting tool material in this sort to cubic nitrogen changes boron (CBN) cutting tool, not coating and coating cermet and improvement coating agglomeration hard alloy. CBN cutting tool because its are tall hardness is charming with wearability. The steel that this kind of cutting tool has reached above in 45HRC and use in cast-iron treatment old. But, the distinctive function as a result of P/M alloy and microscopical the major difference of hardness and macroscopical hardness, make CBN cutting tool can be used at soft to Rockwell hardness the P/M spare parts of 25. Crucial parameter is the hardness of grain. When the hardness of grain exceeds 50HRC, no matter how much macroscopical hardness value is, CBN cutting tool is practicable. The limitation with this kind of apparent cutting tool is their tenacity inadequacy. If be interrupted cutting or the word with the high rate that contain aperture,include to lose arris and heavier honing inside point consolidate is need. Simple light cutting can be finished with the cutting blade of honing. Having the CBN with a few kinds of qualitative material is effective. The talent with first-class tenacity basically is formed by integral CBN character. Their tenacity is wonderful because this is usable,make rough machining. Their limitation is mixed normally the surface is bright and clean degree relevant. Decide by the CBN individual grain that makes cutting tool greatly. Can be in from falling off on cutting blade when grain workpiece material surface produces an effect. And fine grained cutting tool falls off case of a grain criterion is so not severe. The CBN content with the CBN qualitative material that uses normally is high, grain size is medium. Razor blade of CBN finish machining is fine grained and CBN content is low. They are bright and clean to light cutting and surface degree have a demand or by wrought alloy particularly hard circumstance is the most effective. In a lot of cutting application cutting tool life and material pledge sort has nothing to do independently. In other words, material of any a kind of CBN can acquire similar cutting tool life character. Below these circumstances, the alternative with simple material is main it is a basis with the cost lowest of every cutting blade. A round razor blade has one whole CBN end face can offer 4 or more cutting blade, it is cheaper to should set tine CBN bit than 4. The hardness when P/M spare parts under 35HRC, and grain itself hardness does not exceed range, cermet is one of choices normally. Cermet is very hard, can prevent the tumour that accumulate bits effectively and can bear high speed. Additional, because cermet all through the ages uses Yu Gang the high speed with stainless steel, finish machining, they have normally suit to be close to shape the form of ideal geometry chamfer of the spare parts. Today's cermet is daedal on metallurgy, have amount to 11 kinds of alloying element. Normally they are carbolic nitrogen changes titanium (TiCN) grain and Ni-Mo stick the agglomeration that receive a dose and become. TiCN offers very important to using cermet successfully hardness, fight the tumour that accumulate bits and chemical stability. Additional, these cutting tool have normally very tall stick the content that receive a dose, this means them to have good tenacity. Altogether, they have all character that machine P/M alloy effectively. The cermet with a few kinds of qualitative material is effective, just like hard alloy of carbonization tungsten agglomeration in that way, stick the content that receive a dose taller, tenacity is better. Foregone relative to newer progress it is medium deposit of lukewarm chemical gas phase (the advantage that MTCVD) also offers P/M trade. The chemical gas phase with MTCVD traditional reservation is deposit (all CVD) wearability and fight crescent moon to wear away depression return outside function very raise tenacity objectively. The addition of this kind of tenacity basically comes from crackle decrease. Coating issues deposit to cool inside furnace next in high temperature. Expand as a result of heat abhorrent, flaw should be contained in the coating when cutting tool reachs room temperature. The nick that goes up with plate glass is similar, these crackle reduce intensity of cutting tool point. The deposit temperature with MTCVD inferior craft brings about the cutting blade with lower crackle frequency and better tenacity. When the matrix of CVD coating and MTCVD coating identical character and point are repaired when grinding, the distinction of their tenacity can get demonstration. Should use the application that there is a demand in point tenacity, performance of MTCVD coating property exceeds CVD coating. Pass an analysis, when treatment contains the P/M part of poriferous structure, point tenacity is important. MTCVD coating surpasses CVD coating. Deposit of physical gas phase (PVD) coating is thinner and be inferior to MTCVD or CVD coating wear-resisting or be able to bear or endure crescent moon wears away depression. But, circumstance of PVD coating application is to be able to bear to be pounded significantly. When cutting it is abrasive wears away circumstance, CBN and cermet too fragile with need wonderful surface is bright and clean degree, PVD coating can be effective. For example, the cutting blade of C-2 hard alloy is mixed in linear velocity 180m/min feed 0.

15mm/r circumstance issues treatment FC0205. After machining 20 spare partses the tumour that accumulate bits can cause small collapse. Change titanium when use PVD nitrogen (when TiN) coating, the tumour that accumulate bits is restrained and cutting tool life is lengthened. When use TiN coating does this test, the abrasive of P/M spare parts wears away coating of characteristic predicting TiCN will be more effective. TiCN has and TiN is almost identical fight ability of the tumour that accumulate bits but harder than TiN more wear-resisting. Poriferous structure is important and the machinability that it affects FC0208 alloy. When poriferous structure and characteristic change, all sorts of different cutting tool material offer corresponding advantage. When density is low (6.

4g/cm³) , macroscopical hardness is low. Below this kind of circumstance, MTCVD coating hard alloy provides life of optimal cutting tool. The microcosmic exhaustion of cutting blade is very important, point tenacity very suffer take seriously. Good in the tenacity below this circumstance cermet bit provides the greatest cutting tool life. When production density is 6.

The same alloy of 8g/cm³ , abrasive wears away becoming is more important than point crackle. Below this kind of circumstance, MTCVD coating provides best cutting tool life. PVD coating hard alloy has a test to the spare parts of two kinds of extremely good kinds, come up against point burst. Lift when speed () of above of linear velocity 300m/min, cermet even coating cermet also can produce crescent moon to wear away depression. Coating hard alloy suits more, become especially when the cutting blade tenacity of coating hard alloy is good. MTCVD coating arrives the hard alloy of the matrix that has rich cobaltic area especially effective. Cermet is the commonnest use at turning and boring treatment. Because the likelihood expects,inferior speed and more attention accumulate bits tumour, PVD coating hard alloy is very ideal to thread machining. CNC Milling