A hot forming die for a partially closed cylindrical part and a manufacturing process method

Abstract

The present application relates to a kind of local closing cylindrical hot forming die and manufacturing process method, the die includes die, punch, pressing plate;Die, for annular structural member, annular structural member lower end inner hole surface is cylindrical, upper end inner hole surface is circular truncated cone;Punch, for T-shaped columnar structural member, include large end, straight cylinder section, closing section in turn, large end is used as stable in hot forming oven base;Straight cylinder section is cylinder, outer diameter is equal to the inner diameter of closing cylindrical straight cylinder section, realize the straight cylinder section forming of closing cylindrical;Closing section is circular truncated cone, its shape is identical with the inner surface shape of closing cylindrical closing section;Straight cylinder section upper section and closing section are matched with the inner surface of die;Pressing plate, for circular plate structure member, with die, punch is connected by bolt for fixing the relative position between die, punch, the upper surface of pressing plate is the overall stress surface of hot forming stage die.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of local necking cylindrical part hot forming die and manufacturing process method, belong to sheet metal and hot forming technical equipment field. BACKGROUND

[0002] At present, aerospace product parts are developing towards higher efficiency, lower cost, larger batch, titanium alloy is widely used because of its light weight, high thermal strength, good corrosion resistance and other excellent characteristics than other materials.

[0003] The existing local necking cylindrical part mainly has two methods at present: one is to realize the transition of straight cylinder section to necking section by thick-walled pipe machining, and this process method has long processing cycle, very low production efficiency, low material utilization rate, and very high production cost, which cannot meet the quantitative production. Two is to use die hot spinning processing sheet. Hot spinning die processing cost is high, high-strength titanium alloy elastic modulus is small, and there is a large springback after forming, the size after forming is inconsistent, which leads to low production qualified rate of local necking cylindrical part, and in order to meet the size requirement, repeated operation is needed, which leads to long processing time, high labor intensity and low production efficiency. SUMMARY

[0004] The technical problem solved by the present application is to overcome the shortcomings of the prior art, a local necking cylindrical part hot forming die and manufacturing process method, which uses hot forming die forming to meet the production quality requirements of local cylindrical part, improve the production efficiency of parts and reduce the processing cost.

[0005] The technical solution of the present application is: a local necking cylindrical part hot forming die, the local necking cylindrical part includes straight cylinder section and necking section, the straight cylinder section is cylindrical structure, the necking section is circular truncated cone structure, the large end of the necking section is connected with the port of the straight cylinder section, and the inside and outside of the straight cylinder section and the necking section are smoothly transitioned;The die includes concave die, convex die and pressing plate.

[0006] The concave die is an annular structure, the inner surface of the lower end of the annular structure is cylindrical, and the inner surface of the upper end is circular truncated cone;

[0007] The convex die is a T-shaped column structure, which includes large end, straight cylinder section and necking section in sequence, the large end is used as the base of hot forming oven;The straight cylinder section is a cylinder, the outer diameter is equal to the inner diameter of the straight cylinder section of the necking cylindrical part, to realize the forming of the straight cylinder section of the necking cylindrical part;The necking section is a circular truncated cone, and its shape is the same as the inner surface shape of the necking section of the necking cylindrical part;The upper section of the straight cylinder section and the necking section match the inner surface of the concave die.

[0008] The pressing plate is a circular plate structure, and is connected with the concave die and the convex die through bolts to fix the relative positions of the concave die and the convex die.

[0009] Preferably, the partially closed cylindrical part is made of titanium alloy material, and the concave die, the convex die and the pressing plate are made of materials with a thermal shrinkage ratio greater than that of the titanium alloy material.

[0010] Preferably, the concave die, the convex die and the pressing plate are high-temperature resistant and can withstand 750-800 DEG C.

[0011] Preferably, after the hot forming, the outer surface of the convex die and the inner surface of the concave die form the partially closed cylindrical part, and the sizes of the convex die and the partially closed cylindrical part at the same height satisfy the following relationship:

[0012] D = d * (1 - eta)

[0013] wherein D is the diameter of the convex die, d is the inner diameter of the partially closed cylindrical part, and eta is the linear expansion coefficient of the material of the convex die.

[0014] Preferably, the linear expansion coefficient of the material of the convex die is 4.5‰-6‰.

[0015] Preferably, the surface roughness of the inner surface of the convex die and the concave die is 0.8-1.6.

[0016] Another technical scheme of the present application is a manufacturing process of a partially closed cylindrical part based on the above-mentioned die, which comprises the following steps:

[0017] S1, a blank plate is obtained by cutting a flat plate using a laser cutting machine, and then the blank plate is processed into a circle by an automatic two-roll circle machine, and the circumferential straight edge is minimized;

[0018] S2, the plate processed into a circle is welded into a cylindrical part by an automatic argon arc welding machine;

[0019] S3, the cylindrical part is cut off, and the arc starting and arc ending segments of the effective weld at both ends of the cylindrical part are removed;

[0020] S4, the cut-off cylindrical part is sleeved on the convex die from the closing segment of the convex die, the bottom of the cylindrical part contacts the large end of the convex die, and after assembly, the concave die is loaded, the lower end of the concave die is sleeved on the outside of the cylindrical part, and the upper end of the concave die is supported by the cylindrical part;

[0021] S5, the pressing plate, the convex die and the concave die are connected by bolts to fix the relative positions of the concave die and the convex die, then the connection between the pressing plate and the convex die is removed, and hot forming is performed, during which, with the thermal deformation of the cylindrical part, the concave die gradually fits the convex die, and finally the partially closed cylindrical part is formed between the outer surface of the convex die and the inner surface of the concave die.

[0022] S6, demolding and taking out, to obtain a partially closed cylindrical part;

[0023] S7, cutting allowance: installing the partially closed cylindrical part after demolding on a lathe, and cutting off the reserved forming allowance.

[0024] Preferably, before the step S4 is performed, an antioxidant is evenly applied on the outer surface of the truncated cylindrical part.

[0025] Preferably, the specific steps of the hot forming method in the step S5 are as follows:

[0026] S5.1, placing the cylindrical part with the mold into a box furnace;

[0027] S5.2, heating the box furnace to 600-650 DEG C, and keeping the mold and the cylindrical part at the temperature for 1.8-2 hours;

[0028] S5.3, continuously applying a pressure of 300-400 KN to the mold pressing plate by using a stamping device, and keeping the pressure for 30-35 minutes;

[0029] S5.4, fixing the pressing plate and the concave mold and the convex mold, and continuously keeping the box furnace at 600-650 DEG C for 2-2.5 hours to solidify.

[0030] Preferably, the demolding and taking out is as follows: taking off the pressing plate, lifting up the concave mold, and taking out the partially closed cylindrical part from the convex mold.

[0031] The present application has the following beneficial effects compared with the prior art:

[0032] (1) The present application adopts a hot forming mold for processing and forming, eliminates the influence of material springback itself, effectively guarantees the overall size requirement of the part, and is easy to promote quantitative production. Compared with the conventional processing method, the present application can significantly improve the qualified rate of the part and reduce the cost.

[0033] (2) The manufacturing process method of the partially closed cylindrical part provided by the present application adopts a hot forming mold for forming, and realizes high-quality and high-efficiency forming of the partially closed cylindrical part. Compared with the mechanical processing and hot spinning processing of the thick-walled tubular part in the prior art, the production process is simplified under the premise of meeting the high-precision requirement of the product.

[0034] (3) The present application processes the product with significantly improved precision by designing a hot forming mold through an overall process, thereby solving the problems of high cost, low production efficiency, and low qualified rate of the existing forming method.

[0035] (4) The mold of the present application is simple to operate, reduces the labor intensity, and improves the work efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 Figure 1 is a schematic diagram of a hot forming die according to an embodiment of the present application;

[0037] Figure 2(a) is a schematic diagram of a blank flat plate according to an embodiment of the present application;

[0038] Figure 2(b) is a schematic diagram of a truncated cylindrical part according to an embodiment of the present application.

[0039] Figure 2(c) is a schematic diagram of a male die according to an embodiment of the present application;

[0040] Figure 2(d) is a schematic diagram of a partially closed cylindrical part according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] The present application will be further described below with reference to the embodiments.

[0042] Embodiment:

[0043] In one embodiment of the present application, a hot forming die for a partially closed cylindrical part is provided, the partially closed cylindrical part comprising a straight cylinder section and a closed section, the straight cylinder section being a cylindrical structure, the closed section being a truncated cone structure, the closed section being connected to the straight cylinder section at a large end, and the straight cylinder section and the closed section being smoothly transitioned inside and outside.

[0044] In this embodiment, a partially closed cylindrical part is provided, the material of the partially closed cylindrical part being TA15 titanium alloy, the diameter of the straight cylinder section of the partially closed cylindrical part being Φ130mm±0.15mm*180mm, and the thickness being 1.5mm, and the minimum diameter of the closed section being Φ123±0.15mm.

[0045] As shown in Figure 2(d), the die comprises a female die 2, a male die 1, and a pressing plate 3; the surfaces of the female die and the male die are both finished. Figure 1

[0046] The female die is a ring-shaped structure, the inner surface of the lower end of the ring-shaped structure being cylindrical, and the inner surface of the upper end being a truncated cone;

[0047] The male die is a T-shaped columnar structure, comprising a large end, a straight cylinder section, and a closed section in sequence, the large end being used to be fixed on the base of a hot forming oven; the straight cylinder section is a cylinder, the outer diameter of which is equal to the inner diameter of the straight cylinder section of the closed cylindrical part, so as to form the straight cylinder section of the closed cylindrical part; the closed section is a truncated cone, the shape of which is the same as the inner surface shape of the closed section of the closed cylindrical part; the upper section of the straight cylinder section and the closed section are matched with the inner surface of the female die;

[0048] The pressing plate is a circular plate structure, and is connected to the female die and the male die by bolts to fix the relative positions of the female die and the male die, the upper surface of the pressing plate being the overall stress surface of the die during hot forming.

[0049] ​The local closing cylindrical part is made of titanium alloy material, and the concave die, the convex die and the pressing plate are made of material with a thermal shrinkage ratio greater than that of the titanium alloy material, for example, high-temperature-resistant stainless steel 316L.

[0050] The concave die, the convex die and the pressing plate can resist high temperature of 750-800 DEG C.

[0051] The present application needs to design a tooling die, which contains die material, die size and die surface roughness.

[0052] Firstly, the size of the hot forming die is calculated according to the size of the part:

[0053] After the hot forming, the outer surface of the convex die and the inner surface of the concave die form a local closing cylindrical part, and the size of the convex die and the local closing cylindrical part at the same height satisfies the following relationship:

[0054] D=d*(1-η)

[0055] Wherein, D is the diameter of the convex die, d is the inner diameter of the local closing cylindrical part, and η is the linear expansion coefficient of the material of the convex die.

[0056] The linear expansion coefficient of the material of the convex die is 4.5‰-6‰.

[0057] The surface roughness of the inner surface of the convex die and the concave die is 0.8-1.6.

[0058] As shown in Figures 2(a) to 2(d) Based on the above die, the present application further provides a manufacturing process method of a local closing cylindrical part, and the method comprises the following steps:

[0059] S1, using a laser cutting machine to cut a plate to obtain a blank plate, and then using an automatic two-roll coiling machine to coil the blank plate, while minimizing the circumferential straight edge; as shown in Fig. 2(a).

[0060] In this embodiment, the cutting size is: 1.5mm*498mm*180mm, and the accuracy requirement is ±0.15mm.

[0061] S2, using an automatic argon arc welding machine to weld the coiled plate into a cylindrical part, and the welding seam is continuous and uniform, and polishing is not allowed.

[0062] S3, cutting the cylindrical part to remove the arc starting and arc ending segments of the two ends of the cylindrical part, and retaining the effective welding seam; to ensure the forming length of the straight cylinder segment and the closing segment of the local closing cylindrical part; as shown in Fig. 2(b).

[0063] Uniformly apply an antioxidant on the outer surface of the cut cylindrical part, and check whether there are hard points on the surface of the part and the concave and convex dies.

[0064] S4, the truncated cylindrical part is sleeved on the punch from the necking section of the punch, the bottom of the cylindrical part contacts the large end of the punch, and after assembly, the concave die is loaded, the lower end of the concave die is sleeved on the outside of the cylindrical part, and the upper end of the concave die is supported by the cylindrical part;

[0065] S5, the pressing plate and the punch and the concave die are connected by bolts, the relative position between the concave die and the punch is fixed, then the connection between the pressing plate and the punch is removed, and heat forming treatment is performed, during the heat forming process, the concave die gradually fits the punch with the thermal deformation of the cylindrical part, and finally the local necking of the cylindrical part is formed between the outer profile surface of the punch and the inner profile surface of the concave die;

[0066] In the embodiment, the heating temperature of the TA15 titanium alloy plate in the titanium alloy forming method is 650 DEG C, the box furnace is heated to 650 DEG C, the mold is loaded into the oven, the part is uniformly heated in the oven, the holding temperature of 650 DEG C and the time of 2 hours are set, the pressure of the mold pressing plate of the stamping equipment is 30 tons, the holding pressure is 30 minutes, the pressing plate and the concave die and the punch are fixed, and the box furnace is set to 650 DEG C for 2 hours to form.

[0067] S6, demolding and taking out the part to obtain the local necking cylindrical part; the specific steps of demolding and taking out the part are as follows: the pressing plate is removed, the concave die is lifted upwards, and the local necking cylindrical part is taken out from the punch. As shown in Fig. 2 (d).

[0068] The heat forming mold is adopted in the application, the expansion and shrinkage ratios of different materials are different, and there is no relative movement between the part and the inflation mold, so that the part cooled at room temperature is easy to demold.

[0069] In the embodiment, the size of the straight cylinder section is measured to be Φ130±0.15mm, the diameter of the necking end is Φ123±0.15mm, and the roundness is 0.15, which meets the accuracy requirement.

[0070] S7, cutting allowance: the local necking cylindrical part after demolding is installed on the lathe, and the reserved forming allowance is cut off.

[0071] The specific steps of the heat forming method in step S5 are as follows:

[0072] S5.1, the cylindrical part with the mold is placed into the box furnace;

[0073] S5.2, the box furnace is heated to 600 DEG C-650 DEG C, and the mold and the cylindrical part are kept for 1.8 hours-2 hours;

[0074] S5.3, the pressing plate of the mold is continuously applied with a pressure of 300KN-400KN by the stamping equipment, and the pressure is kept for 30 minutes-35 minutes;

[0075] S5.4, the pressing plate and the concave die and the punch are fixed, and the box furnace is kept at 600 DEG C-650 DEG C for 2 hours-2.5 hours to form.

[0076] Using the local necking cylindrical part manufacturing process method of the present example, the part forming qualified rate is increased by 30%, in addition, compared with the existing machining method, the material utilization rate is increased by 50%, the manufacturing cost is reduced by 50%, and the processing efficiency is increased by 30%.

[0077] The beneficial effects of the present application compared with the prior art are:

[0078] (1), the present application improves the material utilization rate by 50% and the part forming qualified rate by 30% through the overall process design of the hot forming die.

[0079] (2), the present application adopts hot forming die machining forming, eliminates the influence of material itself springback, effectively guarantees the overall size requirement of the part, and significantly improves the machining product precision.

[0080] (3), the present application simplifies the operation of the die, shortens the processing cycle, reduces the labor intensity, improves the work efficiency, and is conducive to promoting mass production.

[0081] (4), the present application reduces the manufacturing cost by 50% and improves the processing efficiency by 30% through the overall process design of the hot forming die, thereby reducing the production cost.

[0082] Although the present application has been disclosed as above with reference to the preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application by using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, which does not deviate from the technical solutions of the present application, belongs to the protection scope of the technical solutions of the present application.

Claims

1. A hot forming die for a partially closed cylindrical part, the partially closed cylindrical part comprising a straight section and a closed section, the straight section being a cylindrical structure, the closed section being a frustoconical cylindrical structure, the closed section being connected to the straight section at a larger end of the closed section, the straight section and the closed section being smoothly transitioned on the inside and on the outside; characterized in that The mold comprises a female die, a male die and a pressing plate; The female die is a ring-shaped structural member, the inner surface of the lower end of the ring-shaped structural member is cylindrical, and the inner surface of the upper end of the ring-shaped structural member is frustoconical; The male die is a T-shaped columnar structural member, which comprises a large end, a straight cylinder segment and a necked segment in sequence, the large end is used for being fixed on the base of a hot forming oven, the straight cylinder segment is a cylinder with an outer diameter equal to the inner diameter of the straight cylinder segment of the necked cylinder member, so as to realize the forming of the straight cylinder segment of the necked cylinder member, the necked segment is a frustoconical body with the same shape as the inner surface of the necked segment of the necked cylinder member, and the upper segment of the straight cylinder segment and the necked segment are matched with the inner surface of the female die; The pressing plate is a circular plate-shaped structural member, which is connected with the female die and the male die through bolts to fix the relative positions of the female die and the male die, and the upper surface of the pressing plate is the overall stress surface of the mold in the hot forming stage; The female die, the male die and the pressing plate are made of materials with a thermal shrinkage ratio greater than that of titanium alloy material; After hot forming, the outer surface of the male die and the inner surface of the female die are the necked cylinder member, and the sizes of the male die and the necked cylinder member at the same height satisfy the following relationship: D = d x (1-η) Wherein, D is the diameter of the male die, d is the inner diameter of the necked cylinder member, and η is the linear expansion coefficient of the material of the male die.

2. A hot forming die for a partially closed-end cylindrical part according to claim 1, characterized in that The female die, the male die and the pressing plate can withstand high temperature of 750-800℃.

3. A hot forming die for a partially closed-end cylindrical part according to claim 1, wherein The linear expansion coefficient of the material of the male die is 4.5‰-6‰.

4. A hot forming die for a partially closed-end cylindrical part according to claim 1, wherein The surface roughness of the inner surface of the female die and the male die is 0.8-1.

6.

5. A process for manufacturing a partially closed cylindrical part based on the mold of claim 1, characterized in that The method comprises the following steps: S1, using a laser cutting machine to cut a flat plate to obtain a blank flat plate, and then using an automatic two-roll coiling machine to coil the blank flat plate to minimize the circumferential straight line edge; S2, using an automatic argon arc welding machine to weld the coiled flat plate into a cylindrical member; S3, cutting the cylindrical member to remove the arc starting and arc ending segments of the effective weld at both ends of the cylindrical member; S4, sleeving the cut cylindrical member on the necked segment of the male die, with the bottom of the cylindrical member contacting the large end of the male die, and then assembling the female die, with the lower end of the female die being sleeved on the outside of the cylindrical member and the upper end of the female die being supported by the cylindrical member; S5, connecting the pressing plate with the female die and the male die through bolts to fix the relative positions of the female die and the male die, and then removing the connection between the pressing plate and the male die to perform hot forming treatment, during which the female die gradually fits the male die with the heat deformation of the cylindrical member, and finally the necked cylinder of the cylindrical member is formed between the outer surface of the male die and the inner surface of the female die; The specific steps of the hot forming method are as follows: S5.1, placing the cylindrical member with the mold into a box-type furnace; S5.2, heating the box-type furnace to 600-650℃, and keeping the mold and the cylindrical member at the temperature for 1.8-2 hours; S5.3, continuously applying a pressure of 300-400KN to the mold pressing plate by using a stamping device for 30-35 minutes; S5.4, fixing the pressing plate and the female die and the male die, and continuing to keep the box-type furnace at 600-650℃ for 2-2.5 hours to solidify; S6, demolding and taking out the necked cylinder member; S7, cutting allowance: after the partial necked down cylindrical part is demolded, it is installed on the lathe, and the reserved forming allowance is cut off.

6. A process for manufacturing a partially closed cylindrical article according to claim 5, characterized in that Before the step S4 is performed, the antioxidant is evenly applied on the outer surface of the truncated cylindrical part.

7. A process for manufacturing a partially closed cylindrical article according to claim 5, characterized in that The demolding and taking out is: the pressing plate is removed, the female die is lifted upward, and the partial necked down cylindrical part is taken out from the male die.

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