Exceed the research current situation of fine cermet

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Because cutting tool of cermet of 1 foreword Ti(CN) is had it is the rate of caustic, heat conduction with hard alloy better red rigid, inferior cutting tool and coefficient of friction, better to compare WC radical fight ability sticking a knife, in a lot of treatment the circumstance replaces WC successfully already hard alloy cutting tool. Be in early 20 centuries 60 time, exceed fine WC through refining grain to obtain high strenth, tall hardness and tall wearability base the craft of hard alloy received promotion application, of place preparation exceed fine WC base hard alloy is used extensively at making treatment printed circuit board the miniature broach, needle that print and cutting tool of of all kinds cutting, improved the life of the tool substantially. Can say, craft of the design principle that exceeds fine hard alloy, preparation and manufacturing facilities already all matured quite. But, the research report that improves cermet alloy performance to coming through refining cermet grain is very few, the document that publishs publicly is less than 10. The author hopes to pass the introduction of the research current situation that obtains high grade cermet to refining grain, deepen the understanding of the mechanism that improves alloy performance to refining grain, develop the cermet with superior performance to provide a help as soon as possible for home. The research that 2 exceed method of fine cermet preparation makes progress in recent years, domestic and international preparation exceeded the research of fine cermet to obtain many positive result. Japan develops a respect to occupy world lead position in the development of cermet cutting cutting tool, 30% what its cermet cutting tool holds output of all cutting tool. The research and development that company of 3 water chestnut reported Japan to exceed fine cermet makes progress and rolled out commodity brand NX2525 and NX1010 to exceed fine cermet. The average brilliant granuality that these two kinds of typical features that exceed fine cermet are horniness photograph is less than 1µm, integral performance is very superior. According to the analysis, the preparation method that NX2525 of company of 3 water chestnut and NX1010 exceed fine cermet is: High grade exceed fine Ti(CN) pink or TiC+TiN pink + → of wet grinding of → of fine pink of Ni, Co, Mo2C, TaC, NbL, WC chooses a → → of agglomeration of suppress → atmosphere is hot wait for the static finished product that press → . China in the influence that manage is versed in the Xiong Weihao of the university discussed granuality to refine pair of cermet function in document, think its hardness and intensity raise the cermet that makes with fine raw material apparently. The exceeds fine cermet main preparation means that Xiong Weihao's document offers is: Exceed ball of → of pink of common Mo of ＋ of pink of fine TiC, TiN, WC, Ni to grind → finished product of → of agglomeration of suppress → vacuum. The Xu Yodong of Hefei industry university serves as additive with the TiN of accept rice class recently, undertook to cermet modified studies, obtained the cermet data that wearability improves apparently. Its make a method is: → of wet grinding of → of pink of common TiC of ＋ of accept rice TiN, Mo, Ni, C builds a → finished product of → of agglomeration of suppress → vacuum. From above the report can see, 3 water chestnut companies of Japanese used atmosphere agglomeration and heat to wait in exceeding craft of fine cermet preparation static press a technology, and did not use in relevant research of home. The N2 that uses atmosphere agglomeration technology to be able to restrain TiCN or TiN effectively is decomposed, reduce the possibility that hole produces in alloy significantly; Use heat to wait static press a technology the agglomeration function of ameliorable alloy, eliminate hole, improve the combinative strength of each photograph, improve the performance of alloy in the round thereby. Express component of sample of 1 contrast group new name of company of 1 3 water chestnut exceeds fine cermet NX2525 TiC0.

5N0.

TiC-10% TiN-32% Ni-16% Mo-6 of cermet of fine grain of Ni) 2 of ＋ of TiC-5% TiN-5% WC-5% Mo2C(-5% TaC)-10%(Co of cermet of P10 of traditional brand of Ni) of ＋ of 5-5% WC-5% Mo2C-5%TaC-10% (Co.

TiC-10% TiN-32% Ni-16% Mo-6 of 5% WC comparative cermet.

The comparative basis that 45% TiC-10% TiN(µm)-15% Mo-20Ni-1%C3 of comparative cermet of 45%TiC-10% TiN(nm)-15% Mo-205Ni-1%C of cermet of modified of adulteration of rice of natrium of 5% WC 3 exceeds fine cermet and common cermet afore-mentioned document, the author is fine to exceeding function of the composition of cermet and common cermet, microstructure, physics, cutting function undertook is as follows analytic contrast. New name of company of 3 water chestnut exceeds the Japan that composition contrast has document to report the composition contrast of modified cermet and common cermet sees the accept rice of the fine grain cermet that the document of fine cermet NX2525, Xiong Weihao reports and other document report watch 1. Microstructure is comparative the microstructure SEM photograph that new name of company of 3 water chestnut exceeds cermet of fine cermet, accept rice modified and comparative cermet sees a picture respectively 1 with the graph 2. (New name of company of 3 water chestnut exceeds A) fine cermet (cermet of P10 of B) traditional brand pursues photograph of SEM of 1 cermet microstructure (cermet of modified of A)TiN accept rice (graph of cermet of B) common contrast photograph of SEM of 2 cermet microstructure (× 300) expresses 2 contrast HRA of group sample hardness is transverse rupture intensity N/mm2 1 3.

Cermet of fine grain of 92 1800 2 of cermet of P10 of 4 1830 traditional brand 87.

7 1920 common cermet 88.

1a of 4 1600 graph makes clear, new name of company of 3 water chestnut exceeds Japan the average brilliant granuality of photograph of fine cermet horniness is less than 1µm, and the bead diameter of different particle tends consistent, the hole of alloy gets elimination, compact sex is very good; By document medium labor is knowable, the very typical core in alloy of cermet of the grain in be being done not have in fine cermet exceeds in this kind, loop compose (link is not clear) , its reason remains to study further. Graph 2a makes clear, add TiN accept ground rice to the organization refine action very remarkable, because TiN accept ground rice is in,this basically is on TiC/TiC crystal boundary distributing those who prevented matrix TiC grain is grown. Graph 1b and the average brilliant granuality that graph 2b shows comparative and common cermet are controlled in 2µm, size of granuality of Ju Jing bead not all, difference of the granuality between grain is apparent; In the meantime, put in photograph of clear big grain horniness. Performance of function contrast physics is comparative the hardness that new name of company of 3 water chestnut exceeds cermet of fine cermet, fine grain and common cermet and transverse break by the watch 2 can see, the hardness that 3 water chestnut of Japanese exceed fine cermet and transverse rupture intensity and photograph of traditional P10 cermet rise than all having; And of fine grain cermet transverse rupture intensity rises significantly than common cermet, after watch detail changes grain, the intensity of alloy, tenacity gets bigger improvement. Fine to exceeding cermet is mixed in cutting function document traditional P10 cermet undertook successive turning and concussion cutting experiment, with contrast the wearability of pottery and porcelain of this two metalloid is mixed fight concussion ability. Successive turning experiments: Bit model: TNGG160408R; Process data: 42CrMo4 alloy steel (hardness 220HB) ; Cutting dosage: Cutting speed Vc=200m/min, feed Fz=0.

3mm/r; Cutting means: Do type cutting. Test result is shown 3 times like the graph. Graph cutting of concussion of result of test of alloy steel of 3 successive turning experiments: Bit model: TNGG160408R; Process data: 42CrMo4(hardness 220HB) ; Cutting dosage: Cutting speed Vc=180m/min, ap=1 of deepness of penetration of a cutting tool.

0mm; Cutting time: Tmax=1min; Cutting means: Do type cutting. Test result sees a table 3. Watch 3 note: ● -- state alloy is in achieve × still was not destroyed when appointing number of blows -- state alloy is in achieve when appointing number of blows, happen destroy afore-mentioned test results to make clear, the wearability that exceeds fine cermet and fight concussion ability to rise significantly than traditional P10 cermet. Graph the wear curve of 3 kinds of 4 cutting tool had cermet of modified of rice of document general natrium and common cermet and YG8 hard alloy to undertake cutting contrast experiments, process casting pig work with these 3 kinds of cutting tool respectively namely (cutting parameter: Vc=36m/min, ap=0.

5mm, fz=0.

1mm/r) , the wear out condition of cutting tool is shown 4 times like the graph. By the graph 4 knowable, the wearability of two kinds of cermet greatly excel YG8 hard alloy; The wearability of cermet of sodium rice modified remarkable excel is common cermet. The 4 mechanism that refine grain to improve alloy performance consider to raise a metal to succumb intensity and tenacity to polycrystal, when from what the source gives out a fault is congener the fault encounters a strong fraise (like crystal boundary) and when accumulating of a place of strategic importance rises, will form field of force of very powerful a person operating from within in coordination with outside forces, it is OK that the stress that manages generation in crystal boundary arrives greatly centrally after certain level make a wrong source actuate of photograph adjacent bead, produce deformation; But in general, deformation is affected by a grain to Xiang Linjing bead is more difficult. Of material succumb the relation of stress and brilliant granuality can take the stress that causes in crystal boundary place explain centrally by slippage. From slippage the stress of the ministry that bring end looks centrally, can regard slippage as a crackle, but each other have the two sides of crackle attrition, two faces have relatively slip but not detached. The length that establishs slippage zone and grain dimension D are identical, adscititious shear stress is Dy, the each attrition obstruction of slippage is equal to DI, criterion the effective stress that action forms a bad stuff to accumulate on slippage belt is Dy-dI, bad stuff is accumulated should be according to computation in the stress that is apart from a place of strategic importance to accumulate group of L that carry a department to be in (DyGdI)(d/l)1/2. When this stress achieves critical value Dn, can spark the slippage of the place. Produce this as polycrystal macroscopical the condition that succumb, namely only slippage can come from one grain transmission when another grain, polycrystal ability generation is macroscopical succumb, because this can be gotten (Dy-dI)(d/l)1/2=dn makes Ky=dnl1/2, go up type but type of melt into Dy=dI+Kyd-1/2 (1) (1) is famous Hall-Pety formula namely. By Hall-Pety formula knowable, of polycrystal succumb stress Dy and grain dimension D become inverse ratio, namely of polycrystal succumb to reduce and increase what stress follows grain measure. This shows, refining grain is to raise a metal to succumb the important step of intensity. With general aggrandizement the method often can make metallic brittleness increases photograph comparing, through refining grain not only the strength that can increase metallic stuff, still can raise tenacity at the same time. Because grain heals,this is fine, it is difficult to heal the stress concentration that creates need of place of crackle form nucleus. In the meantime, grain heals fine, crackle is in different to the transmission inside each grain is more difficult also. Increase brittleness data bending strength according to Guerlande (Gurland) intensity is academic, horniness photograph ply of photograph of the felt between two grain (L) of average and free run is changed along with felt appearance content and carbide grain size, namely the F in L=(1-f)/NL (2) type -- the bulk mark NL of carbide photograph -- the blame on unit length is successive when grain number is studying the function of WC-Co hard alloy and average and free run concerns, intensity theory points out Guerlande: To the hard alloy of certain part, when average freedom distance is 0.

3 ～ 0.

When 6µm, the intensity of alloy reachs maximum, the meet an emergency that can transmit crackle place to need through wrapping Fu grain can estimate critical rupture intensity, meet an emergency can make an appointment with a fault that stands by grain matrix interface to be quantity of matrix flexibility model for µn2b2(µ , n is a bad number, b is) of vector of cypress family name, crackle appears in grain when, meet an emergency can transform for expression can, namely µn2b2=2g, critical stress decides by next type: (The S in Qs-s0)2=Kgmf2/3/ds2=Kf2/3/d (3) type -- axial stress Q -- stress doubly coefficient S0 -- shift is segregate a stress F that wrong place needs -- the bulk mark D of WC -- the average size G of WC -- the surface of WC can K, k -- invariable type (the concern that 3) says to understand alloy intensity and average size, can use at explaining congener horniness data. In Ti (C, n) fund belongs to material of pottery and porcelain in, grain of the carbide in the alloy that makes up by fine pink is fine, namely average size D is lesser (about 0.

5µm) , according to type (3) , the intensity of this alloy can rise. In the meantime, because the composition of alloy is certain, what because this carbide of petty grain is helpful for photograph of felt of get along with of the horniness in alloy,organize is even distributing, make the blame on unit length successive grain number NL increases, from type (2) can see, when NL increases, l drops. According to the report of some document, the brilliant granuality of the average and free Cheng of G photograph and carbide has distinct effect to the bending strength of TiC-Mo2C-Ni alloy, in G photograph average and free Cheng is about 0.

3µm, alloy has the greatest bending strength. So, the bending strength of the alloy that the alloy that fine pink makes up in the experiment makes up than meal wants tall. Above analysis makes clear, through refining the brilliant granuality of cermet, the performance characteristics of cermet will get bigger improvement, obtain the cermet data with more superior performance. CNC Milling CNC Machining