Drop forging method of magnesium wheel forgings for light vehicles and a magnesium wheel forging shaped in this way

Abstract

The subject of the invention is a method of drop forging a magnesium wheel forging for light vehicles and a magnesium wheel forging produced by this method, characterised in that the upper drop forging die (1) having a working impression (la) in the central part and the lower drop forging die (3) having a working impression (3a) in the central part in the form of a lump whose outline is similar to a circle with circular recesses in the centre, is heated in a furnace to 260 °C to 300 °C, after which the heated upper drop forging die (1) is mounted to the ram of the hammer forging by means of a dovetail (lb), and the heated lower drop forging die (3) is mounted by means of a dovetail (3b) to the anvil block of the drop forging hammer, and then the forging preform (2a) in the form of a forging preform cast into metal moulds of magnesium alloy AZ31 (Mg-3Al-lZn) is heated in a furnace to a temperature of 350 °C to 440000 °C, for a period of 40 to 45 min, after which the heated preform (2a) is placed in the working impression (3a) in the lower forging die (3), then the upper forging die (1) is driven in a downward progressive motion with a velocity (VI) of 7 m / s towards the lower drop forging die (3) and the upper drop forging die (1) is impacted with a maximum impact energy in the range of 9, 14 to 11.17 kJ is crushed with the working impression (2a) of the upper drop forging die (1) and the working impression (3a) of the lower drop forging die (3), forming the wheel preform (2b) with a deformation ranging from 6.41 to 10.6. The object of the invention is also a magnesium wheel forging for light vehicles produced by the aforementioned method.

Description

[0001] DROP FORGING METHOD OF MAGNESIUM WHEEL FORGINGS

[0002] FOR LIGHT VEHICLES AND A MAGNESIUM WHEEL FORGING SHAPED IN THIS WAY

[0003] 5 The obj ect of the invention is a method of a magnesium wheel drop forging for light vehicles and a magnesium wheel forging produced by this method .

[0004] The methods of producing magnesium alloy wheels for light vehicles are known and used to date , such as , casting , machining ,

[0005] 10 drop forging .

[0006] For magnesium alloy wheels producing the casting technology is used, which was described in the literature by K . E . Oczos , A . Kawalec "Shaping light metals" ( Polish : Ks ztaltowanie metali lekkich ) , Wydawnictwo Naukowe PWN, Warsaw 2012 and A. . Luo

[0007] 15 "Magnesium casting technology for structural applications" , Journal Magnesium Alloy, 2013 , vol . 1 , pp . 2-22 . The most commonly used types of magnesium alloy wheel casting are gravity casting , high pressure casting or low pressure casting . Due to the strong reactivity and the need for a protective atmosphere , magnesium

[0008] 20 alloy wheels are most often cast in the process of hot or cold chamber casting . This process helps obtain products with high properties .

[0009] Pressure die-casting offers attractive flexibility in the design and manufacture of magnesium wheels . Pressure die¬

[0010] 25 casting of magnesium alloy wheels are designed with thin walls in areas where the product should not have high strength and with thicker walls in areas with higher strength requirements .

[0011] Non-pressure die-casting of magnesium wheels takes place in sand and metal moulds , by the full mould method or by the smelted

[0012] 30 models method . Non-pressure die-casting of magnesium wheels is rarely used due to the inferior mechanical properties of the castings , surface roughness and lower dimensional accuracy compared to the wheels obtained by the pressure casting method . Cast magnesium wheels are characterized by high dimensional accuracy and low production costs . Cast wheels have casting defects such as: heterogeneity of structure, coarse grain, blisters, porosity, shrinkage cavities, rust, which affect their lower properties compared to those obtained by plastic processing methods .

[0013] When generating magnesium alloy wheels, the machining technology is used, which is described in W. Olszak's literature "Machining", Wnt, Warsaw 2008. The machining of magnesium alloy wheels consists in giving the surfaces the desired shape, dimensions and surface quality by removing the material from the impression in the form of a roller using cutting tools. This method is labor-intensive, time-consuming and energy-intensive. During the machining process of magnesium wheels, large material losses are generated, and the quality of the obtained products is lower than that obtained by plastic processing methods.

[0014] The best mechanical and functional properties of magnesium alloy wheels for light vehicles are ensured by the plastic processing processes described in the literature by K. E. Oczos, A.Kawalec "Shaping light metals", Wydawnictwo Naukowe PWN, Warsaw 2012 and J. Sihczak "Processes of plastic processing", Wydawnictwo Naukowe AKAPIT, Krakow 2003. An example of the process is drop forging described in specialist literature by P. Skubisz "Technologies of drop forging" (Polish: "Technologie kucia matrycowego " ) , ARBOR FP, Krakow 2010 and L. Gebrehiwet, Y. Negussie, A. Tadesse "Business Opportunity of Wheel Rim Manufacturing in Ethiopia", International Journal of Advances in Engineering and Management, 2022, vol. 4, pp. 1148-1159. The drop forging process of a magnesium alloy wheel forgings is carried out in three stages - swelling, pre-forging, final forging of a semi-finished product in the form of a roller produced by extrusion. Expensive tool-mounted heating systems are used for the process. This method produces a large technological waste, which is 50% of the forging weight. A method of forging a semi-finished product on a hammer is known from the description of patent under the number PL 237778 Bl , in particular for the production of an aviation fastening, wherein the upper and lower dies having working impressions in the central part are heated in a furnace using gas burners to a temperature of 300 ° C and placed on a forging hammer with an impact energy of 36 kJ and a ram mass of 1000 kg . The input material in the shape of a shaped forging preform cast in sand moulds from less malleable magnesium alloys of the magnesium-aluminium-zinc group is heated in a furnace in the temperature range of 400 - 430 ° C , preferably 420 ° C , for up to 45 minutes . The heated input material is placed in the working impression of the lower die . Subsequently, the upper die is set in progressive motion with a velocity of up to 8 m / s towards the lower die and the input material is compacted with the working impression of the upper die and the working impression of the lower die and a semi-finished product is formed with a lower degree of forging . Numerical and experimental studies for the method according to the patent PL 237778 Bl is shown on the example of magnesium alloy AZ 61 in the article by A . Dziubinska, P . Surdacki , K . Maj ers ki "The Analysis of Deformability, Structure and Properties of AZ 61 Cast Magnesium Alloy in a New Hammer Forging Process for Aircraft Mounts" , Materials , 2021 , vol . 14 , no . 10 , pp . 1-25 . It has been proven to improve the functional and mechanical properties of castings subj ected to heat-plastic processing according to the method from the patent description .

[0015] The obj ect of the invention is to produce a forging of the AZ31 magnesium alloy wheel for light vehicles in a single treatment by drop forging on a drop forging hammer from a preform into a forging preform cast into metal moulds of the AZ31 magnesium alloy, limiting the labor intensity and energy intensity of the process , the material loss of the products produced by multi-stage forging and machining, and the poor quality of the products produced by machining and casting in sand moulds . The essence of the invention is a method of drop forging a magnesium wheel hammer forging for light vehicles on a hammer, characterised in that the upper drop forging die and the lower drop forging die having in the central part working impressions in the form of a lump whose outline is similar to a wheel with circular recesses in the centre are heated in a furnace. Then, the upper die is dovetailed to the ram of the drop forging die hammer and the lower die is dovetailed to the anvil block of the drop forging die hammer, after which the preform is heated in the furnace, placed in the working impression of the lower drop forging die, after which the upper drop forging die is driven in a progressive motion towards the lower drop forging die and the impact of the upper drop forging die is crushed by the working impression of the upper drop forging die and the working impression of the lower drop forging die and the wheel forging is formed. The upper drop forging die and the lower drop forging die are heated in the furnace to 260°C to 300°C and a preform in the form of a forging preform forged magnesium alloy AZ31 (Mg-3A1- IZn) shall be heated in a furnace at 350°C to 400°C for a period of 40 minutes to 45 minutes, and the heated preform shall be forged with the upper drop forging die, driven in a progressive motion towards the lower drop forging die with a velocity of 7 m / s with a maximum impact energy in the range of 9.14 to 11.17 kJ and a wheel forging is formed with a maximum deformation in the range of 6.41 to 10.6. The preform, with a volume of 81315.2 mm3 and a mass of 0.1447 kg, is shaped like a barrel 48.5 mm high and 49.7 mm in diameter at its widest point, which subsumes a lower base 43.1 mm in diameter and an upper base of 42.61 mm, with a circular recess in the lower base 16.93 mm in diameter and 6.5 mm high, and the walls of the barrel inclined at an angle of 7.°.

[0016] Preferably, the preform is heated in a furnace at a temperature of 400°C.

[0017] Preferably, the preform is heated in a furnace for 40 minutes . The essence of the invention is also a wheel forging produced by the method as described above .

[0018] It is an advantage of the present invention that the generation of a preform for the forming process allows material savings in relation to the currently used machining technologies and multi-stage forging . The use of a preform for the shaping process makes it possible to obtain more accurate shapes of wheel forgings without excessive flash, which has a positive effect on the reduction of technological waste in relation to the production methods used so far .

[0019] Another advantage of the present invention is also that the generating method according to the invention allows for the generation of wheel forgings that are characterized by better quality associated with the fragmentation of the structure and obtaining a high surface smoothness , which translates into better mechanical properties in relation to products made by casting in sand moulds and machining .

[0020] The invention is described in the embodiments and in the drawing in which :

[0021] FIG . 1 shows a perspective view of the drop forging dies with a broken-out section with the preform;

[0022] FIG . 2 shows a perspective view of drop forging dies in contact with broken-out section the wheel forging;

[0023] FIG . 3 shows a perspective view of the upper drop forging die ;

[0024] FIG . 4 shows a perspective view of the lower drop forging die ;

[0025] FIG . 5 shows a top perspective view of the preform;

[0026] FIG . 6 shows a bottom perspective view of the preform;

[0027] FIG . 7 shows a longitudinal section of the preform;

[0028] FIG . 8 shows a top perspective view of a wheel forging;

[0029] FIG . 9 shows a bottom perspective view of a wheel forging;

[0030] FIG . 10a shows the distribution of deformations in the wheel forging in a top view for the temperature of forging dies of 260 ° C and a preform of 350°C according to the invention obtained from FEM simulations;

[0031] FIG. 10b shows the distribution of deformations in the wheel forging in a bottom view for the temperature of forging dies of 260°C and a preform of 350°C according to the invention obtained from FEM simulations;

[0032] FIG. 10c shows the distribution of deformations in the wheel forging in a top view for the temperature of forging dies of 260°C and preform of 400°C according to the invention obtained from FEM simulations ;

[0033] FIG. lOd shows the deformation distribution in the wheel forging in bottom view for a temperature of forging dies of 260°C and a preform of 400°C according to the invention obtained from FEM simulations ;

[0034] FIG. lOe shows the distribution of deformations in the wheel forging in a top view for the temperature of forging dies of 300°C and preform of 350 °C according to the invention obtained from FEM simulations ;

[0035] FIG. lOf shows the distribution of deformations in the wheel forging in a bottom view for the temperature of forging dies of 300°C and a preform of 350°C according to the invention obtained from FEM simulations;

[0036] FIG. 10g shows the deformation distribution in the wheel forging in top view for a temperature of forging dies of 300°C and a preform of 400°C according to the invention obtained from FEM simulations ;

[0037] FIG. lOh shows the distribution of deformations in the wheel forging in a bottom view for the temperature of forging dies of 300°C and a preform of 400°C according to the invention obtained from FEM simulations;

[0038] FIG. lOi shows the distribution of deformations in the impression in a top view made on the basis of patent document PL 237778 Bl and obtained from a FEM simulation; FIG. lOj shows the distribution of deformations in the impression in a bottom view made on the basis of patent document PL 237778 Bli and obtained from FEM simulation;

[0039] FIG. Ila shows a graph of flow curves of AZ31 magnesium alloy cast in metal moulds at 350°C;

[0040] FIG. 11b shows a graph of flow curves of AZ31 magnesium alloy cast in metal moulds at 400 °C;

[0041] FIG. 11c shows a graph of flow curves of AZ31 magnesium alloy cast in metal moulds at 450°C;

[0042] FIG. lid shows a graph of flow curves of AZ61 magnesium alloy cast in sand moulds at 350°C;

[0043] FIG. lie shows a graph of flow curves of AZ61 magnesium alloy cast in sand moulds at 400°C;

[0044] FIG. Ilf shows a graph of flow curves of AZ61 magnesium alloy cast in sand moulds at 450°C;

[0045] FIG. 12a shows a graph of the dependence of the impact energy of the upper drop forging die as a function of time for a drop forging die temperature of 260°C and a preform temperature of 350°C according to the invention, obtained from FEM simulations;

[0046] FIG. 12b shows a graph of the dependence of the impact energy of the upper drop forging die as a function of time for a drop forging die temperature of 260°C and a preform temperature of 400°C according to the invention, obtained from FEM simulations;

[0047] FIG. 12c shows a plot of the dependence of the impact energy of the upper drop forging die as a function of time for a drop forging die temperature of 300°C and a preform temperature of 350°C according to the invention obtained from FEM simulations;

[0048] FIG. 12d shows a plot of the dependence of the impact energy of the upper drop forging die as a function of time for a drop forging die temperature of 300°C and a preform temperature of 400°C according to the invention obtained from FEM simulations; FIG . 12e shows a graph of the dependence of the impact energy of the upper drop forging as a function of time based on patent document PL 237778 Bl and obtained from a FEM simulation .

[0049] For the drop forging die method of the magnesium wheel forging for light vehicles , examples 1 - 4 use a preform with a volume of 81315 . 2 mm3 and a mass of 0 . 1447 kg, which has a barrel shape with a height of 48 . 5 mm and a diameter of 49 . 7 mm at its widest point , having a lower base of 43 . 1 mm diameter and an upper base of with a diameter of 42 . 61 mm, the lower base having a circular recess 16 . 93 mm in diameter and 6 . 5 mm high, and the walls of the barrel inclined at an angle of 7° .

[0050] Example 1 .

[0051] The drop forging die method for a magnesium wheel forging for light vehicles and a magnesium wheel forging produced by this method, intended for a wheelchair .

[0052] The upper drop forging die 1 and the lower drop forging die 3 , which have working impressions la and 3a in the central part in the form of a circular outline with circular cavities in the centre , were heated in a furnace at 260 ° C . The upper drop forging die 1 was then dovetail-mounted lb to the ram of the drop forging hammer and the lower drop forging die 3 was dovetail-mounted 3b to the anvil block of the drop forging hammer . Then, a forging preform 2a in the form of a die cast into magnesium alloy metal moulds AZ31 (Mg-3Al-lZn) according to ASTM B107-13 was heated in a furnace at 350 ° C for 45 minutes . The forging preform 2a was then arranged in the working impression 3a of the lower forcing die 3 . The upper forging die 1 was then driven in a progressive motion with a velocity of 7 m / s towards the lower forging die 3 and the impact of the upper forging die 1 crushed the forging preform 2a of the working impression la of the upper forging die 1 and the working impression 3a of the lower forging die 3 with a maximum impact energy of 11 . 17 kJ and a wheel forging was formed with a maximum deformation of 7 . 88 .

[0053] Example 2 .

[0054] The drop forging die method on a magnesium wheel forging for light vehicles and a magnesium wheel forging produced by this method, intended for a wheelchair, implemented according to example 1 , whereby the forging preform 2a was heated in a furnace at 400 ° C for 40 minutes . The forging preform 2a was then arranged in the working impression 3a of the lower forcing die 3 . The upper drop forging die 1 was then driven in a progressive motion with a velocity of 7 m / s towards the impact of the lower drop forging die 3 crushed the preform 2a of the working impression la of the upper drop forging die 1 and the working impression 3a of the lower forging die 3 with a maximum impact energy of 9 . 15 kJ and a wheel forging was formed with a maximum deformation of 10 . 6 .

[0055] Example 3 .

[0056] The drop forging die method on a hammer of a magnesium wheel forging for light vehicles and a forging of a magnesium wheel produced according to the method, intended for a wheelchair , implemented according to Example 1 , wherein the upper forging die 1 and the lower forging die 3 having working impressions in the middle part la and 3a in the form of a lump whose outline is similar to a circle with circular recesses in the middle , were heated in a furnace at a temperature of 300 ° C , the forging preform 2a was heated in a furnace at a temperature of 350 ° C for 45 minutes . The forging preform 2a was then arranged in the working impression 3a of the lower drop forcing die 3 . Then the upper drop forging die 1 was set in motion into a progressive motion with a velocity of 7 m / s towards the lower drop forging die 3 and impacting the upper drop forging die 1 , the forging preform 2a was crushed with the working impression la of the upper drop forging die 1 and the working impression 3a of the lower drop forging die 3 with a maximum impact energy of 11 . 17 kJ and the wheel forging was shaped with a maximum deformation of 6 . 41 .

[0057] Example 4 .

[0058] The drop forging die method on a hammer of a magnesium wheel forging for light vehicles and a magnesium wheel forging produced in this way, intended for a wheelchair, implemented according to Example 1 , wherein the upper drop forging die 1 and the lower drop forging die 3 having working impressions in the middle part la and 3a in the form of a lump whose outline is similar to a circle with circular recesses in the middle , were heated in a furnace at a temperature of 300 ° C, the preform 2a was heated in a furnace at a temperature of 400 ° C for 40 minutes . The preform 2a was then arranged in the working impression 3a of the lower drop forcing die 3 . The upper drop forging die 1 was then driven in a progressive motion with a velocity of 7 m / s towards the lower drop forging die 3 and the impact of the upper drop forging die 1 crushed the preform 2a of the working impression la of the upper drop forging die 1 and the working impression 3a of the lower drop forging die 3 with a maximum impact energy of 9 . 14 kJ and shaped the wheel forging with a maximum deformation of 8 . 91 .

[0059] A wheel forging made of AZ31 magnesium alloy with higher mechanical properties resulting from a more favorable structure of the shaped product in relation to the products made by casting and machining were obtained .

[0060] A comparative analysis was carried out using the Finished Element Method ( FEM) of the drop forging die method for a magnesium wheel forging for light vehicles and a magnesium wheel forging produced by this method according to the invention - model 1 (Ml . 1 - Ml . 4 ) and the forging method for a semi-finished product , especially for the manufacture of an aviation fastening . based on the patent document PL 237778 Bl - model 2 (M2 ) . The numerical analysis was carried out in a system designed to simulate plastic working processes - 3D Deform in accordance with the parameters adopted in Table 1 . For the FEM analysis , the developed models of magnesium alloy materials AZ31 were used and AZ 61 magnesium alloy based on plastometric tests .

[0061] Table 1 - Comparison of the method according to the invention with the state of the art

[0062] These tests were carried out for a metal-cast magnesium alloy of grade AZ31 according to ASTM B107 -13 and a sand-cast magnesium alloy of grade AZ 61 according to ASTM B951-10 with the chemical composition presented in Table 2 .

[0063] Table 2 - The chemical composition of the magnesium alloy AZ31 used in the process according to the present invention according to ASTM B107-13 and the magnesium alloy AZ 61 according to ASTM B951-10 used in the process according to PL 237778 Bl .

[0064] Plastometric tests were performed on a deformation dilatometer at temperatures of 350°C, 400°C, 450°C at deformation velocities of 0.1 s-1; 1 s-1; 10 s-1. Based on the obtained results from the measurements, the flow curves for the AZ31 alloy presented in the graphs of Fig. Ila - 11c and for magnesium alloy AZ61 shown in the graphs of FIGS, lid - Ilf. The numerical simulations analysed the maximum impact energy of the upper drop forging die as a function of time, the maximum deformation in the shaped products, the contact area of the shaped forging with the upper drop forging die, the contact area of the shaped forging with the lower drop forging die for both methods analysed with the lower drop forging die for both methods analysed.

[0065] The maximum impact energy of the upper drop forging die obtained from the numerical analysis and the maximum deformation in the shaped forging according to the invention - Ml .1 - Ml .4 are shown in FIG. 12a - 12d and FIG. 10a - lOh. The maximum impact energy of upper drop forging die and maximum deformation in the shaped impression obtained from the numerical analysis performed on the basis of patent document PL 237778 Bl - M2 are presented in the graph of FIG. 12e and Fig. lOi and lOj .

[0066] List of reference symbols

[0067] 1 - upper drop forging die la - working impression of the upper drop forging die lb - dovetail of the upper drop forging die

[0068] 2a - preform

[0069] 2b - wheel forgings

[0070] 3 - lower drop forging die 3a - working impression of the lower drop forging die 3b- dovetail of the lower drop forging die

[0071] Vi - upper drop forging die velocity

Claims

Claims1. The drop forging method on a hammer of magnesium wheel forging for light vehicles characterized in that the upper drop forging die (1) with a central working impression (la) and a lower drop forging die (3) with a central working impression (3a) in the form of a lump whose outline resembles a circle with circular recesses in the centre, is heated in a furnace to a temperature of 260 °C to 300 °C, after which the heated upper drop forging die (1) is mounted to the ram of the drop forging die hammer by means of a dovetail (lb) , and the heated lower drop forging die (3) is mounted by means of a dovetail (3b) to the anvil block of the drop forging hammer, and then the preform (2a) in the form of a forging preform cast into metal moulds of magnesium alloy AZ31 (Mg-3Al-lZn) is heated in a furnace to a temperature between 350 °C and 400 °C for 40 to 45 minutes, then the heated preform (2a) is placed in the working impression (3a) of the lower drop forging die (3) , wherein the upper drop forging die (1) is moved in a downward progressive motion with a velocity (VI) of 7 m / s towards the lower drop forging die (3) and impact the upper drop forging die (1) with a maximum impact energy in the range of 9.14 to 11.17 kJ to crush the preform (2a) with the working impression (la) of the upper drop forging die (1) and the working impression (3a) of the lower drop forging die (3) , shaping the wheel forging (2b) with deformation in the range from 6.41 to 10.6.

2. The method according to claim 1, characterised in that the preform (2a) , with a volume of 81315.2 mm3 and a weight of 0.1447 kg, is shaped like a barrel 48.5 mm high and 49.7 mm in diameter at its widest point, which supports a lower base 43.1mm in diameter and an upper base 42.61 mm in diameter, the lower base having a circular recess 16.93 mm in diameter and 6.5 mm high, and the walls of the barrel inclined at an angle of 7° 3. The method according to claim 1, characterised in that the preform (2a) is heated to 400 °C, in 40 min.

4. The wheel forging is generated as defined in claims 1 to 3.

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