One, foreword is machined to cutting for, good position should be treatment surface layer the base material under the facing that be the same as a watch is consistent, the exterior change that satisfies treatment to go out namely is the smallest, best even it is to did not change. Already machined exterior metamorphism layer generate go up objectively saying is inevitable, but the generation that a lot of methods can reduce it. The article is based on effect of workpiece material Bauschinger, use converse essence to cut a method, already machined exterior metamorphism layer in order to reduce. 2, the cutting of law of converse essence cutting is out of shape model attempt shows the cutting that is law of converse essence cutting 1 times to be out of shape the model is graphic. Cutting tool is shown with be like plan institute to thick cut work, be out of shape in plasticity as a result of the metal in the process, because grain crystal lattice suffers the effect of force, and generation slippage, distortion, grain is broken brilliant surface is rough, grain becomes fine and grow and direction tends gradually consistent, it is certain to be shown consequently directional, already machining the surface to form degenerative layer. When cutting tool with with thick when cutting the cutting career choice that is the same as direction, essence of life cuts the farther flow that will cause grain, crystal lattice is crooked twist He Jing bead to spin further, plasticity metabolic increases, crystal is increased to the obstruction of slippage, the aggrandizement action that closes to denaturalize layer increases holds dominant position, bring about degenerative layer to increase. Think degenerative layer deepness is only commonly ten micron arrive a few micron. If to thick after cutting, be less than degenerative layer ply to undertake cutting of converse essence of life with cutting deepness, can cutting thick cut share of meet an emergency of apparently big plasticity while, make already machined the grain of facial cent below the surface to organize flow to also be returned together, cause the flow that grain returns, those who close to denaturalize layer is reduced is weak change action to hold dominant, degenerative layer reduces the surface accordingly. Because be the negative charge that counters direction, according to Bauschinger effect, treatment sclerosis can get comparativing the refreshment of degree. Light plays an experiment to make clear, when cutting tool the workpiece that cut a person is formed when cutting bits, the workpiece data that cuts line upside is supporting complex plasticity is out of shape, this kind is out of shape can expand the bottom that cuts a line. Accordingly, in surface layer limits memory is in certain deepness to play plasticity. Converse bear makes the meet an emergency of part of workpiece lower flexibility can get fixed rate release. The law gets such converse precision work already machined the surface and normally treatment method photograph is compared, its are rough degree reduce, exterior surface roughness is low, wearability rises. Accordingly, use to thick after cutting, undertake converse essence cuts line of this one craft, can reduce the generation of exterior metamorphism layer effectively. 3, the converse essence cutting that is based on Bauschinger effect is out of shape mechanism JohanBsuschinger passes pair of steel to undertake a series of drawing and the discovery after reducing a test, during be out of shape reversely its yield point is reduced, the one-way drawing that measuring certainly namely or the junior travel that reduce plasticity deformation turn over directional to load, of material succumb intensity is met under succumbing to metabolic continuously intensity, this kind of phenomenon says for Bauschinger effect. Can come with quantity of a retrorse meet an emergency effect of mensurable description Bauschinger, quantity of this one retrorse meet an emergency is what stress changes to wait for Yuzheng to be achieved to deformation place on numerical value to make flow reversely after showing load is retrorse is the biggest stream change stress, the size of the add meet an emergency that should add. If graph 2a place is shown, in drawing of ABC delegate odd axis to be out of shape, c is to uninstall a dot. CD is drawing is uninstalled paragraph, and DEF is retrorse (compress) to load paragraph. No matter to load direction is,still turning over, be worth stress and accumulate meet an emergency to measure new picture to be in graph 2b. Here, ABCD represents drawing paragraph, and DEF is to reduce to load share. At the same time growing to be nodded to C to sclerotic Duan Yan, then the line segment CC of approximate parallel is mixed between EF stream change the stress parameter that the Dsb of twinkling time difference of stress level shows Bauschinger effect with tabulation, its report is alleged " permanent bate " degree. As similar as this, the biggest the positive and negative that ordering C place part to tensile stress differs Deb to the meet an emergency between is a parameter of feature of meet an emergency, call Bauschinger meet an emergency. To steel, their sclerotic mechanism basically is mixed the slippage that is out of shape place arises is concerned, OK and pure go analysing Bauschinger effect from the angle of slippage. Of converse essence cutting be out of shape the experiment is the same as to observe contrast to, the plasticity of converse fine vehicle is out of shape circumstance, undertake as test specimen with 45 medium carbon steel with 10 mild steel turning experiments respectively, use metallographic technology to make workpiece already machined metallographic grind segment of the surface, metallographic metallograph is obtained below PMEOLYMPUSTOKYO optical microscope. The mechanical sex visibility that uses test specimen data is expressed 1. Express brand of data of performance of machinery of material of 1 test specimen sectional dimension (Sb(MPa) of tensile strength of type of Mm) heat treatment succumbs outspread rate of intensity Ss (MPa) (%) shrinkage (%) hardness (HB)1025 normalizing 34021031551434525 anneal 6103601640197 pursue 3 for turning the metallographic metallograph of 10 mild steel. In PMEOLYMPUSTOKYO optics microscope falls, cut to essence of life together with what digital camera films, the grain flow that converse essence cuts sees graph 3a, 3b respectively. Graph 4 for turning the metallographic metallograph of 45 medium carbon steel. Cut to essence of life together, the grain flow that converse essence cuts sees graph 4a, 4b respectively. By the graph 3, graph analysis of 4 considerable examine is cut to essence of life together, the circumstance that the grain flow that converse essence cuts changes. If the place in the graph is shown, because exceed the change that give workpiece material yield point and produced microcosmic organization, behave those who be grain or crystallization organization to spin reach treatment sclerosis to wait. Be crystal lattice to show of fine vehicle series to add of thick car succeed crooked twist He Jing bead to spin further, flowing to what car alignment behaves converse essence to be returned to cause grain after thick car. Afore-mentioned test results are further test and verify graph the cutting of the law of converse essence cutting of 2 is out of shape the validity of the model. To score analyse 10 mild steel are mixed of 45 medium carbon steel be out of shape the circumstance is knowable, because the plasticity of mild steel is good, reason from macroscopical on look than 45 easier report, difference of metabolic of cutting of converse cutting alignment. But of different material but converse cutting is out of shape the mechanism still needs very thorough research to analyse immanently. But the article thinks the Bauschinger effect of material still is to cause, cutting of converse cutting alignment is out of shape one of main reasons of immanent difference. Think the mechanism that produces Bauschinger effect has two kinds commonly normally, it is short distance effect firstly, this and metallic stuff are medium change concerns an instruction that wrong motion place gets. It is long Cheng effect secondly, the internal stress that appears in one-way drawing or process of circular to load with material namely or back stress are concerned. Macroscopical on say, succumb intensity begins plasticity metabolic to fight force on behalf of crystal. From wrong viewpoint looks, stream change in the begining, already had on slide surface enough a much fault had swept quite large area, succumb intensity is being represented happen many a wrong hyperplasia and the shear stress that move and make slippage belt broadens, succumb so the size of intensity is with wrong removability becomes inverse ratio. Combine short distance effect, be out of shape to the Bauschinger effect of converse essence cutting the mechanism undertakes an analysis. When be out of shape to cutting, the fault moves along some slide surface, encounter forest wrong and bend, meeting v/arc be on the throne is wrong as a result ahead, make forest wrong density increases, form a fault intricate or afterbirth shape organization. Graph 5 forest if the influence of wrong contrapuntal wrong motion pursues 5 in the position is shown 1 times, this is planted the structure is in a fault mechanical going up is quite stable, form field of force of very powerful a person operating from within in coordination with outside forces to crystal succumb have distinct block up effect. Accordingly, if be uninstalled right now,be the same as along with succeed add to cutting, alternate route cannot make remarkable motion. But if uninstall hind retrorse cutting, be equivalent to bringing to bear on retrorse force, the fault is forced to move reversely, because be on reverse path, resemble forest wrong measure of this kind of barrier is less, and the ahead that also is not located in slippery shift fault to move fitly certainly, be less than in a wrong obstruction when be out of shape reversely continue to a wrong obstruction when be out of shape. Reason the fault can leave mobile larger space in inferior stress. If first to load makes the line is in a fault the position in the graph 2, again retrorse to load also can appear similar case. The plasticity in metallic cutting process is out of shape can produce internal stress, the internal stress that produces is helpful for a wrong growth, but the motion that goes against a fault. The occurrence of internal stress is considered as the main mechanism that Bauschinger effect produces. Among them the fault is all round crystal boundary the main source that the occurrence of accumulation and Orowan annulus is internal stress generation. Research shows this kind of internal stress can conduce to a wrong motion after retrorse to load, to continueing to be out of shape have block up effect, and conduce to be out of shape reversely. The computation of internal stress is in the Bauschinger effect of metallic stuff, internal stress is having very main effect. Moan and Embmp put forward to apply to the model of internal stress computation of general metal stuff, this model thinks to affect to stream change the element of stress has 3: Solid dissolve aggrandizement and make the earliest a group a fault is derivative the stress to intensity contribution that carries an obstacle, namely initiative succumb stress, write down S0; Movable a fault and forest wrong interact arises forest sclerotic contribution, write down Sd; The contribution of action of precipitation photograph particle in the average stress on matrix or back stress, write down SMF. If use formula to express, to the middle of deformation always flow change stress is of Sf =s0 +sd +sMF(1) says to be out of shape from plasticity normally before beginning to rupture be out of shape the process runs to flow process, every flashy stress says to flow change stress. In cutting process, stream change stress makes namely a the least stress that the fault passes crystal place continuously to need. Should flow reversely variable and to when shedding variable to comparative, deformation will surely overcome S0 and Sd quite surely, nevertheless right now, SMF won't block up is retrorse deformation, conduce to instead produce retrorse deformation. Accordingly, always flow reversely change stress becomes of Sr =s0 +sd -sMF(2) by above two type are knowable, dsb of stress of the Bauschinger in graph 2b is Zulfikar H of of Dsb =sf +sr = 2sMF(3) . A.
Kassam offerred another model on the foundation of model of internal stress computation in Moan and Embmp. The Sf in type of of Sfc=syc+Dsfor -Dsb(5) of ≡ of Sf ≡ Sft=syt+Dsfor +Dsb(4)sr falls in drawing circumstance -- , material is in to the Dsfor of of the greatest stress when to load -- , as a result of wrong interference or forest sclerosis brings about stream change stress increment Dsb -- , , material is in the Sfc of the greatest stress when drawing -- , after adding stress beforehand, data yields in the compensation when compressing stress by above two type can get Dsb=½(sft-syc-syt+syc)(7) of stress of less than of place of Sft-sfc=syt -syc + 2Dsb(6) to be in compress a circumstance to fall, the direction of internal stress is retrorse, namely Dsb=-½(sft-syc-syt+syc)(8) 4, epilogue is comparative to, converse cutting alignment, combine Bauschinger effect, from the angle consideration of wrong motion, the internal stress that the plasticity in metallic cutting process is out of shape place arises can conduce to a wrong motion of converse cutting alignment, benefit at be out of shape reversely. And right to cutting alignment continuity to be out of shape have block up effect, go against continue to be out of shape. But alignment of converse essence cutting, in adjusting cutting area the condition of wrong generation and motion, changed reach between the fault a fault and between all sorts of obstacles the feature of interaction, metabolic of stimulative metal plasticity undertakes, can reduce the generation that already machined layer of exterior face metamorphism effectively. CNC Milling
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