齿轮锻造工艺设计说明书（Gear forging process design manual）Gear forging process design manualAbstract: the purpose of forging blank molding, and control of its internal organizational performance reached the desired geometry, size and quality of forgings, steel and non-ferrous metal and alloy has the most plastic in different degrees, can be plastic molding process in cold or hot. The forging of gears adopts the free forging process. This paper mainly introduces the free forging process of gears. Free forging is the use of pressure or impact force is the metal between the upper and lower iron deformation between plastic deformation, so as to obtain the shape and size of the required method. The determination of free forging becomes the key to free forging. This article focuses on the process of free forging of gears.Keywords: free forging, gear processing, plastic deformation, process flow.CatalogI. introduction............................................... ............. OneTwo. Overall design plan................................................ OneThree. Specific design methods and steps.................................... Three3.1 draw the forging drawing............................................. Three3.2 determine the deformation process.......................................... Three3.2.1 upsetting............................................. Three3.2.2 punching............................................. Four3.2.3 reaming............................................. Four3.2.4 trimming forgings....................................... FourThree3 calculate billet quality and size................................. Four3.4 selection of equipment and specifications (iv)Four. Process flow (process card)....................................... SixFive. Conclusion............................................................ SevenSix. Thanks..................................................... ....... SevenSeven. References................................................. ..... EightManufacturability analysis of forging structureforging drawingParameter selectionDetermination of machining allowance and determination of tolerancesDetermine billet qualityDetermination procedureSelection of forging equipmentDetermination of heating temperature and heating timePost forging heat treatmentThe 1. part drawing process, attached to the instructions, the A4 paper to print or freehand.2. front cover format:1. design specifications must be written, with A4 paper, cover, catalogue, text and references.Advanced design and manufacturing integrated experimentXX part XX process designclassFull nameI. IntroductionThe purpose of forging is to make the blank forming and to control its internal structure to achieve the required geometry, size and quality of the forgings. The basic process of forging is free forging, die forging, sheet metal stamping, in which free forging and die forging are thermoplastic forming, and sheet stamping is cold plastic forming, the basic principle of both is the same.The proportion of forged parts shows the status of a country's production level, productivity, material utilization, production costs and product quality in international competition. Before the founding of new China, forging was basically a continuation of handicraft workshops, with low production efficiency and great labor intensity. However, after the reform and opening up, China's forging technology hasbeen rapid development, which led to the automotive industry, such as leaps and bounds. But we should also clearly see that our forging technology level and European and American developed countries still have a certain gap, which makes us more efforts to develop new technologies, catch up with the international advanced level.Gear is a large number of parts used in modern industry. This paper discusses the free forging production of gears. Free forging can be carried out a lot of processes, can be divided into basic processes, auxiliary processes, and finishing process three major categories. Its basic process is to make the metal produce a certain degree of plastic deformation in order to achieve the desired shape and size of the process, such as upsetting, drawing, punching, bending, cutting, twisting and dislocation and other processes.Two, the overall design1. draw the forging drawingAccording to the basic drawing of parts drawing, combined with the characteristics of free forging, the residual parts, forgings allowance and forging tolerances are drawn.2. calculate billet quality and size(1) calculation of billet quality;According to the shape and size of forging, forging quality can be calculated first, then consider the oxidation loss duringheating, loss of core material and flush cutting head punching, quality first for the calculation of blank forgings, the calculation formula is as followsM billet, =m forging, +m firing, +m head, +m core(2) determination of blank size;The leather size are correlated with the first basic process, because the gear is cake or hollow forgings, with upsetting forging process, in order to avoid upsetting bending, should make the blank height h of not more than 2.5 times the diameter of D, which bases on the ratio of height to diameter less than 2.5 h/D. In order to facilitate operation during cutting, the blank height h should be less than 2.5D, that is, the ratio of height to diameter should be greater than 1.25Diameter of round material.3. choose the forging processGear forging, according to its lateral size greater than or near the height of the characteristics, mainly to upsetting the main, when the forging has a convex shoulder, according to the size of the shoulder pad selection ring, upsetting or partial upsetting. If the forging hole needs to be rushed out, it needs to be punched.4. selected forging equipmentThe selection of forging equipment is based on the material,size and quality of the forgings, as well as the existing equipment conditions of the workshop. If the equipment tonnage is too small, the forging internal is not thorough, the productivity is low, but the equipment and power waste, and the operation is inconvenient and unsafe, usually by empirical analogy or look-up table method.(1) empirical analogyAccording to the empirical formula of hammer tonnage:The upsetting forging hammer tonnage G= (0.002-0.0003) KS (kg)(2) look-up table selectionFor low carbon steel, medium carbon steel and ordinary low alloy steel, the free forging can be checked by the selected tonnage.5. determine the forging temperature and specifications(1) determine the range of forging temperatureThe forging temperature range of all kinds of alloy steel can be found from the table. The basic principle is to ensure that the steel has good plasticity and low deformation resistance in the range of forging temperature, and can forge high quality forgings,And a wide range of forging temperature and less heating times, as well as higher productivity.(2) determine the range of heating and coolingFor the carbon structural steel with a good thermal conductivity and a diameter of less than 150~200mm, a section of heating code shall be adopted, and the furnace shall be controlled at a temperature of 1300 ~1350 c.. When the billet is heated to the initial forging temperature, it is immediately baked and forged.(3) determination of cooling methods and specifications;Choose air cooling, pit cooling or furnace cooling as required. Small and medium carbon steel and low alloy steel are forged by air cooling method with faster cooling rate. Carbon tool steel, alloy tool steel and bearing steel, forged, air cooled, blown, or sprayed quickly to 200 degrees, then put the forgings into a pit or cooled in a furnace.Three, the specific design methods and steps1. draw parts drawingThe material of this part is 40Cr, and the production is small in quantity. The gear blanks are forged by free forging.The gear on the circumference of the small groove shoulder and 8 x 30mm diameter hole part, the free forging method is very difficult to form these parts, considering the feasibility and economy of technology, and decided not forged, and the additional block shape to simplify the forging, forging. After forging the gear blank, it can be further processed and finallyAccording to the dimension of the parts drawing, the height and the diameter of the parts listed in the comparison table, the allowance and tolerances for the machining of the gear forgings can be found out. D=289, h=52, machining allowance and tolerance check for horizontal forging forging height direction a=10 + 4, b=9 + 3, c=13 + 5 hole bilateral, and press check tolerances can be drawn numerical Shoulder Gear Forging drawing.Forging drawing is given separately.2. determine the deformation processConvex shoulder shaped gear forgings belongs to the hollow part, according to the shape and size of forgings, forging in the forging hammer, and the main deformation process for upsetting and punching, punch reaming process, the auxiliary cushion ring upsetting forming is determined according to the forging of the shoulder shape.At present, these kinds of short swords generally use partial upsetting, while upsetting forming is suitable for shoulder forgings with small diameter and height. Because the gear diameter is larger, so we decide to use the punch reaming, but considering the punching metal will flow along the radial hole, and along the height direction of the shoulder pulling shrinkage phenomenon, so that the cushion ring upsetting after the diameter size should be smaller than the diameter of the forging, and shoulder height should be greater than the forging(1) upsettingSince the forgings are single sided, the pad ring shall be upset, and the ring size shall be determined here.Cushion ring cavity volume V pad should be more than the volume of the forging shoulder volume V, shoulder big 10% - 15% (thick wall take small value, thin wall take big value), this case take 12%, calculate V shoulder =753253mm3. beV pad = (1+12%) V shoulder =1.12 * 753253=843643 mm3Taking into account the hole will produce shrinkage, cushion ring height H pad should be increased by 15% to 30% than the convex shoulder (thick wall take small value, thin-walled take big value), this example take 20%.H pad, =1.2H shoulder, =1.2 * 34=40.8 (mm), take 40mm. The inner diameter of the cushion ring D pad can be inconvenient to obtain according to the volumeThe inner wall of the cushion ring should have a slope of 7 degrees, and the upper aperture shall be 163mm, and the lower end aperture shall be 154mm.In order to remove the oxide, the flat anvil upsetting shall be carried out before the pad ring upset, and the process is shown as shown in fig.. After upsetting the flat anvil, the diameter of the billet should be slightly smaller than the innerdiameter of the gasket ring, and the diameter of the upper flange at the upper flange shall be smaller than the maximum diameter of the forging ring after upsetting.(2) punchingPunching punching should make the core material loss is small, while expanding the number of not too much, D punching hole diameter should be less than or equal to D/3 or D at less than D/3=213/3=71mm, the practical use of d=60mm.(3) reaming;The total reaming amount is the hole diameter of the forging minus the punching diameter, that is, (131-60) =71mm, the amount of reaming is 25~30mm in general, and the amount of reaming is 21mm, 25mm and 25mm respectively.(4) trimming forgingsTrim according to the forging drawing.3. calculate billet quality and sizeThe quality of the billet is equal to the quality of the forging, plus the quality of the core and the quality of burning. The quality of the forgings is calculated according to the formulaM forging =V forged P = Pi /4 (32 * 0.27+2.112 * 0.34+1.322 * 7.8=17.8kg * 0.61)Quality of punched core material (take d=60mm, H=65mm) asM core = (1.18~1.57) D2 * H=0.3kgThe gas furnace heating billet loss rate u =2%, considering the need of forging after 2~3 reaming, and requires at least 2 heating, therefore should take the upper limit of single fire damage rate plus appropriate loss value is =0.035, so the quality of the billet is burningM burn =17.8 * 0.035kg=0.6kgTherefore, the quality of the blank isM billet, =m forging, +m firing, +m head, +m core, =18.7kgWhen calculating the diameter of the blank, the die can be calculated by upsetting:Table look-up shows that the diameter of standard hot rolled round bar is determined by the diameter of the selected billet D=120mm.Billet lengthThus, the blank size is determined to be Phi 120 * 210mm.4. selection of equipment and specificationsThe forging type belongs to the ring, D=289, H=52, the look-up table should be used 5kN hammer. 40Cr is an alloy structuralsteel. The temperature of the starting forging is 1200 degrees and the final forging temperature is 800 degrees. Because of the forging is the diameter of 200~350mm medium carbon structural steel, the three stage gas furnace heating specification, charging temperature of 1150 DEG ~1200 DEG, the holding time is about the total heating time (1h~100min) 5%~10%, here is 15min with maximum insulation, heating speed is heated to 1200 DEG C after thermal insulation again about 15min after the start of forging.Cooling method: the forging is a kind of medium and low alloy structural steel, and it can be cooled by air cooling.Four 、 process flow (process card)Forging name, gear (forging drawing shall be given separately)Forging material 40CrBillet quality 18.7kgBlank Size 120 * 210mm0.5T free forging hammer forging equipmentSchematic diagram of fire operation procedure1 blankingThe quality and size of the billet can be calculated from the forging drawing at phi 120 * 210mmUpsettingLocal upsetting of cushion ringH pad =40mm,D pad =164mm2 punchingD Chong =60mmPunch reamingIt is divided into three reaming, and each reaming amount is 21mm, 25mm, 25mmDressingTrim according to the forging drawingFive. ConclusionBy using the above process, the gear blanks can be forged, and then the gears can be produced as long as the cutting process is formed. I think why not directly machining, but advanced forging it? The reason must be that forging can not only make its initial shape, but more importantly, forging can improve the mechanical properties of parts and improve its toughness and strength. Therefore, the key parts of the key parts shouldbe forged first, then cut into shape.Six, thanksThrough this hot processing course design, I deeply understand the importance of hot processing in industrial production. I do is the forging process design of gear, the process of gear machining are deeply discussed, which let me learn a lot, and I will be more efforts to improve and perfect their knowledge, to face greater challenges in future work. In this course design, XXX teacher gave me great help, thank you once again, but also to thank my own efforts of these days, the sweat will be watered out of successful flowers.Seven. References[1] Wang Aizhen, foundation of hot working technology, Beijing, Beihang University press[2] Wang Aizhen, metal forming process design, Beijing, Beihang University press[3] Hu Yamin, forging process and die design, Beijing, Peking University press。
