The magnetism that crankshaft induction quenchs heats up coupling research

Summary: The article uses ANSYS/Multiphysics finite yuan of analysis software, use magnetism, hot, solid coupling analyses a way, induction of imitate crankshaft surface quenchs process, get temperature field and leftover stress field distributing, comparing result of knowable computer simulation by what measure result and imitate computation outcome actually is authentic. Keyword: Crankshaft; The induction quenchs; Leftover stress field; 1 foreword of coupling 　 　 crankshaft is one of the most important parts in internal-combustion engine, the dynamical source unit that the spare parts such as it and air cylinder, piston and connecting rod formed engine, output power outwards by crankshaft. Complex, stress centers crankshaft appearance the phenomenon is quite serious, special come in brace near the round horn intermediate zone of journal, lube aperture and machine coarse place stress to center a phenomenon to be highlighted particularly. As the development of internal-combustion engine and aggrandizement, make the working requirement all the more of crankshaft slashing. Accordingly, the intensity of crankshaft and stiffness problem become more severe. Exterior induction quenchs can make crankshaft surface produces remains to press stress, can raise intensity of workpiece bend fatigue to reach significantly turn round fatigue intensity. In the following use condition, as a result of the leftover stress that quench and arises, its size and distributing the mechanical function to material all influential, become the matter that produces all sorts of limitation. The control of leftover stress and the serious problem that quench the strain that create is to be designed. The induction heats the process is very complex. Need imitate normally a group complex nonlinear multidimensional coupling problem includes electromagnetism field, temperature field, quench process, structural change, be out of shape, auxiliary circuit is waited a moment. The article uses ANSYS/Multiphysics finite yuan of analysis software, induction of imitate crankshaft surface quenchs process, get the induction heats and quench temperature and leftover stress distributing, undertook comparative with actual measurement result. Induction of 2 crankshaft surface heats quench problem description and simplify Wen Zhongmo drafts the crankshaft that computation uses is some diesel engine the crankshaft of 6 crocks of diesel engine that the factory produces, the material of crankshaft is 42CrMoA, use intermediate frequency induction to heat quench device undertakes quenching to crankshaft surface. Connecting rod journal quenchs heat process power is 90 ～ 120kw, voltaic frequency is 10kHz, heat on average because induction coil is hemicycle,time is 14s(, because this is heating surface of the crankshaft in the process each bits heat on average time is 7s) . The cooling fluid of gush of surface of Kong Xiang journal that goes up through induction coil when refrigeration (AQUATENSID BW) , cooling time is 18 ～ 20 seconds. After refrigeration of eject cooling fluid ends, crankshaft cools in park air. The situation that the article stabilizes one kind relatively suppose. Crankshaft heats in the induction rotate with fixed rate in the process, with there is opposite campaign between inductor. Model of computation of article lieutenant general simplifies, slice of axial of edge of connecting rod journal, through tracking among them the understanding that temperature change course will come to realize circumstances of pair of change of workpiece whole temperature. Graph 1 to simplify the crankshaft induction after quenchs sketch map. Graph 1 crankshaft induction quenchs 3 inductions of 　 of 　 of sketch map Fig1 Scheme Of Induction Hardening Of A Crankshaft heat 　 of computation of temperature field imitate 3.

1 finite yuan of model crankshaft intermediate frequency each journal section undertakes quench, part of journal of crankshaft connecting rod is axial symmetry appearance, n/ele be induced by backset and the electromagnetism field on the load that brings to bear on and workpiece, temperature field distributinging also is axial symmetry, because this is taken,quench the 1/2 part with sectional part makes calculation. Location of round horn of journal of the connecting rod below working status suffers stress the biggest, the article takes journal of a connecting rod to undertake building a model. Considering leakage magnetism phenomenon, need the partial air all round countershaft neck to build a model, crankshaft, inductor is included to reach in computational model all round air. [1] although actual in induction coil is quadrate and sectional hollow copper pipe, but because those who bring to bear on is in in computation,be current density load, because this is replaced with sincere,can not affect what be worth to coil electric current to compare test and verify hollowly. Use Plane13 of unit of 2 dimension substance to build an induction to heat physical field model. Graph 2 differentiate for physical field unit graph. Share 5910 unit, 4398 node. Graph unit of 2 physics field differentiates graph Nextpage 　 　 3.

2 inductions heat induction of result of temperature field computation heats time is 7 seconds, the article heats up induction of coupling law computation to quench temperature field heats in the process with direct magnetism. Undertake harmonic electromagnetism is analysed above all, undertake transient state heats up an analysis next, repeat inside different time-interval undertake electromagnetism field analysis will amend its the influence to temperature. [2] graph 3 heat for the induction the music axle temperature after the process ends spends distributinging figure. By the temperature of computational result distributinging cloud atlas can be seen the induction heats the surface is highest Wen Wei 992 ℃ , when these quantity of heat return future to pass into interior so that reach, the surface layer of be heated warms up quickly to be changed to austenite of above of austenite transition temperature. Crankshaft core temperature is room temperature 25 ℃ . Graph 3 inductions heat 　 of 　 of Fig3 The Temperature Field Of Induction Hardening In 7 Seconds of field of the temperature when 7 seconds 3.

Field of 3 cooling temperature is calculated in the imitate computation of the article, take no account of cooling process the steam film that initiative phase cooling fluid makes in crankshaft surface, heat exchange condition can simplify the heat exchange condition that is cooling fluid and crankshaft surface, in arrive without gush the surface of cooling fluid, press the computation of heat exchange condition of air and crankshaft surface. [3] the article analyses law computation to quench with transient state heat cooling temperature field. Use Plane55 of unit of 2 dimension substance to build quench model of cooling temperature field. Share 2800 unit, 2926 node. Graph 4 cool to quench temperature field is narrow yuan of model. Graph 4 quench cooling temperature field is narrow graph of yuan of 　 of model Fig4 The FE Model Of Hardening Coolant Temperature Field 5 cool for eject cooling fluid the temperature field of 18 seconds, by the temperature of computational result distributinging cloud atlas can be seen crankshaft cools in eject cooling fluid after 18 seconds, exterior thermal drop comes 25 ℃ , core temperature is 197 ℃ . In cooling process exterior quantity of heat is conducted to core make crankshaft core temperature elevatory. Because exterior cooling rate is very rapid, exceeded critical cooling rate, exterior organization becomes martensite with respect to change and core is organized changeless. Graph 5 refrigeration the 　 of temperature field Fig5 The Temperature Field Of Cooling In 18 Seconds of 18 seconds pursues 6 come to cool for long in air the temperature field when room temperature distributings, cooling in air time is 2300 seconds about. The course cools for long in air, crankshaft surface and core already replied room temperature 25 ℃ . Right now transient state stress can serve as leftover stress approximately. The graph cools in 6 air computation of imitate of field of 4 leftover stress is opposite the 　 of 　 of temperature field Fig6 The Temperature Field Of Air Cooling In 2300 Seconds Nextpage after 2300 seconds domestic and internationally in last few years the demand that its remains stress forecasts before component part is being made is more and more pressing, computational metal workpiece quenchs process remains stress, in mechanical on attribute an analysis a kind of heat plays plasticity problem. 4.

1 finite yuan of model because the article uses field of stress of indirect method computation, because this model is built,divide with reseau analyse must the computational model with temperature field is same, set air and induction coil unit to disable (NULL) is unit, temperature place is structural unit PLANE42 with unit PLANE55 changeover, hold unit number and knot check the number changeless. Finite of yuan of model and field of temperature of computational crankshaft refrigeration finite yuan of model is same (4) seeing a picture. 4.

2 computation pursue as a result 7 be field of stress of remains of the axial on journal of the connecting rod after quenching distributing, flat the leftover stress of paragraph of journal surface was achieved - 666Mpa, stress value achieves crankshaft core remains - 369 MPa. Graph 　 of Fig7 The Axial Residual Stress Distribution of distributinging graph of stress of 7 axial remains pursues the 8 axial remains stress that for journal deepness of flat Duan Sui changes distributing. The abscissa shows the chooses crankshaft center distance inside crankshaft, ordinate states stress is worth size. From inside the graph the OK and intuitionistic remains that sees crankshaft surface concentration is very big presses stress. Leave the surface further to press stress smaller, when achieving certain distance, press stress for 0, turn to pull stress. Pulling stress is to increase first, reduce gradually next, great value appears among, crankshaft core presses stress for remains. Graph 8 journal are flat the axial remains stress that Duan Sui deepness changes distributings 　 of 　 of Fig8 The Axial Residual Stress Distribution Of Journal With Depth Change 4.

3 experiments and computational result trade off study used blind aperture law to undertake to the connecting rod journal of this crankshaft leftover stress checks. The meeting when bore causes add strain, because this measures an outcome,have certain error. The leftover stress that next watches are calculated for imitate and the experiment gets is compared. Leftover stress result is expressed quite by the watch 1 can see, computational imitate result and actual measurement value are basic be identical, this specification uses computer simulation to quench temperature field and leftover stress field have feasibility, the crankshaft geometry form that can develop level with already lying to optimize and leftover stress distributing provide reference. The imitate of temperature field numerical value that 5 conclusion quench through heating to crankshaft induction, can more thorough analysis induction heats reach quench the temperature of the crankshaft in the process changes, reach a design at quenching the development of craft is analysed with benefit. By the computation of leftover stress imitate result and actual measurement value are compared knowable, use computer simulation to quench temperature field and leftover stress field have feasibility, the crankshaft geometry form that can develop level with already lying to optimize and leftover stress distributing provide reference. CNC Milling