A processing method for bending and forming a multi-folded angle workpiece

Abstract

The present invention discloses a processing method for bending and forming a multi-folded angle workpiece, which includes an upper die body, a lower die body and a middle die body. An installation groove is arranged on the lower die body, a spring is arranged inside the installation groove, a guide body slidably matched with the installation groove is arranged at the bottom of the middle die body, and a bearing slot for installing the spring is arranged on the upper part of the guide body. A forming area one is arranged on one side where the lower die body and the middle die body face each other, and a forming area two is arranged on one side where the middle die body and the upper die body face each other. The nine-section bending processing of the workpiece is completed through three times of forming, especially the U-shaped return folding structure can be completed only through two times of forming.

Description

Technical Field

[0001] The present invention relates to the technical field of bending dies for nine-fold workpieces, and particularly to a processing method for bending and forming multi-fold-angle workpieces. Background Art

[0002] Under the pressure of the upper die or the lower die of a bending machine, a metal sheet first undergoes elastic deformation and then enters plastic deformation. In the initial stage of plastic bending, the sheet is freely bent. As the upper die or the lower die presses on the sheet, the sheet gradually clings to the inner surface of the V-shaped groove of the lower die. At the same time, the radius of curvature and the bending force arm also gradually become smaller. Continuing to apply pressure until the stroke ends, the upper and lower dies and the sheet are in full contact at three points. At this time, a V-shaped bend is completed, which is commonly known as bending.

[0003] Such as Figure 6 shown is a nine-segment bent workpiece. Since this nine-segment bent workpiece has a U-shaped re-bending structure and the two sides of this U-shaped re-bending structure respectively have an L-shaped fold angle and a re-bending angle in the form of an obtuse angle, it is impossible to complete the bending processing quickly and efficiently. After retrieval, CN103624164A is a special bending machine special die for Z-shaped workpieces and its processing method for the upper die, belonging to the field of die design. Its device includes an upper die, an inner die, and a lower die. The upper die from top to bottom is successively a die clamping part, the middle part of the upper die, and the working part of the upper die. The working part of the upper die is successively connected and composed of a first vertical surface of the upper die, a first horizontal bottom surface of the upper die, a second vertical surface of the upper die, a second horizontal surface of the upper die, a third vertical surface of the upper die, and a first inclined surface of the upper die from left to right; the included angle between the third vertical surface of the upper die and the first inclined surface of the upper die is 25°; a semicircular arc transition is adopted at the intersection of the third vertical surface of the upper die and the first inclined surface of the upper die, and the radius of this arc is equal to the thickness of the workpiece to be processed. This technology cannot fold out the above re-bending structure and needs at least three times to fold out the above U-shaped re-bending structure, and the processing efficiency needs to be further improved.

[0004] CN114540699A Preparation method of high-performance hot work die steel. Based on the composition of H13 steel, the alloy composition is optimized by adopting the composition design idea of low C, low Si, high Mo and composite Ni microalloying. The mass percentage of chemical components is as follows: C 0.34% - 0.39%, Mn 0.35% - 0.55%, Si 0.20% - 0.35%, S ≤ 0.001%, P ≤ 0.008%, Cr 4.90% - 5.10%, Mo 2.3% - 2.6%, V 0.50% - 0.70%, Ni 0.25 - 0.35%, Cu ≤ 0.08%, and the rest is Fe. And the residual gas content is: H ≤ 1.5 ppm, O ≤ 13 ppm, N ≤ 90 ppm. At the same time, the production process is strictly controlled. The specific process route is as follows: Electric furnace smelting, ladle furnace refining, vacuum refining furnace refining, inert gas protection electrode blank casting, protective atmosphere constant melting rate electroslag remelting, high-temperature homogenization treatment, multi-directional forging, post-forging pretreatment, and ultra-fine grain treatment are adopted simultaneously. The present invention also relates to a high-performance hot work die steel. The annealed microstructure of this product is uniform, with good spheroidized structure and fine and uniform grain distribution. The quenched and tempered structure is uniform. The fine precipitation phases of Mo, Cr, and V carbides play a dispersion strengthening role during use. At the same time, an appropriate amount of Ni element can increase hardenability, refine grains, and increase the toughness and fatigue resistance of the steel.

[0005] However, it is ignored that the die set also needs to have a certain wear resistance. At the same time, there are some forming areas with special angles on its upper part, such as forming grooves with small angles. When forming the upper die, there will inevitably be some structural stresses, which are likely to cause micro-cracks in the forming area at small angles. Secondly, the above process requires ultra-high temperature and long-time high-temperature diffusion, which is likely to oxidize the easily oxidized metal elements to form oxides. The oxides themselves contain a large number of micropores and cracks, increasing the unreliability of the die steel performance, resulting in loose structure and destroying the performance continuity of the die steel material. Especially during forging, it is easy to affect the processing performance of forgings. Summary of the Invention

[0006] The purpose of the present invention is to solve the deficiencies in the prior art. Therefore, a processing method for bending and forming multi-fold angle workpieces is proposed. The remaining bending segments and the initial shape of the U-shaped return fold structure are respectively folded out through forming area one and forming area two. After the initial shape of the U-shaped return fold structure is folded out, the final structure of the U-shaped return fold structure is folded out in the rear horizontal area of forming area one, thereby completing the final processing of the three-step nine-fold workpiece. The bending efficiency is high and only a single set of dies is required to complete the bending process of the nine-fold workpiece.

[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A multi-folded workpiece bending and forming die, comprising an upper die body, a lower die body and a middle die body. The lower die body is provided with installation grooves, and springs are arranged inside the installation grooves. The bottom of the middle die body is provided with guiding bodies that are slidably fitted in the installation grooves, and the upper part of the guiding bodies is provided with socket slots for installing springs. A first forming area is arranged on one side where the lower die body and the middle die body face each other, and a second forming area is arranged on one side where the middle die body and the upper die body face each other;

[0009] The components and mass percentages of the middle die body are as follows: 0.17 - 0.52 parts of C, 0.17 - 0.31 parts of Si, 5.44 - 8.15 parts of Mn, 7.13 - 11.58 parts of Cr,

[0010] 4.15 - 6.55 parts of Ni, ≤0.02 parts of P, ≤0.02 parts of S, 0.021 - 0.038 parts of Nb, 0.012 - 0.017 parts of Y, 0.07 - 0.23 parts of Ti, 0.08 - 0.14 parts of B, and the balance is Fe and impurities;

[0011] Among them: Ti = 0.21Nb + Y + 0.34C + S;

[0012] Among them: Si = 0.21B + 0.015Ni + Cr;

[0013] The forming area of the upper die body is provided with a Ti-xY wear-resistant alloy layer.

[0014] By adopting the above scheme, the remaining bending segments and the initial shape of the U-shaped return folding structure are respectively folded out through the first forming area and the second forming area. After the initial shape of the U-shaped return folding structure is folded out, the final structure of the U-shaped return folding structure is folded out in the horizontal area at the rear side of the first forming area, thereby completing the final processing of the three-step nine-fold workpiece. The bending efficiency is high and only a single set of dies is required to complete the bending process of the nine-fold workpiece.

[0015] By adopting the above scheme: By reasonably quantifying Si, Si dissolves in the alloy matrix and has a solid solution strengthening effect. B is used to form hard metal compounds with Ni and / or Cr, so that it is dispersed in the alloy and plays a dispersion strengthening role, which can improve the hardness and wear resistance of the hard alloy. Due to the addition of Cr, it can have a solid solution strengthening effect on Ni and enhance the passivation ability, and can also form hard metal intermetallic compound phases with B and Si, playing a dispersion strengthening role to improve wear resistance. Since B and Si are added, the overall solid-liquid phase temperature range of the upper die body steel is relatively wide, with excellent fluidity and wettability, and the process performance of the upper die body steel will be better; salts with low density, low viscosity and good fluidity will form on the surface of the molten steel and float up, protecting the alloy from oxidation and preventing the generation of pores.

[0016] A reasonable amount of Ti (0.21(Nb+Y)+0.34(C+S)), when Ti forms TiC, Nb and Y can make the primary TiC dendrites smaller, increase the dendrite spacing, increase the slender eutectic titanium carbide to obtain ultrafine-grained TiC, and the ultrafine-grained TiC at the Nb and Y purification interface increases the interface wettability, so that it can be evenly dispersed in the alloy matrix with a higher density. When microcracks and residual stress are generated around the ultrafine-grained TiC, they can pin the cracks and consume the fracture energy, thereby improving the toughness of the alloy material and the processing performance of the forging. TiN, TiC and Ti(C, N) precipitates in steel can prevent the growth of austenite grains during heating and forging, and inhibit the recovery and recrystallization of deformed austenite grains. The deformation bands and unrecovered substructure boundaries in austenite can further promote the refinement of ferrite grains, which can play a role in refining the organization and grains, thereby improving the strength and impact toughness of steel. Ti's affinity with S is stronger than that of Mn with S. As the Ti content increases, the Ti4C2S2 compound in the steel gradually increases and replaces the MnS inclusions, that is, the addition of Ti takes away the S in MnS and forms a more stable Ti4C2S2 with it, which can reduce the precipitation of MnS. The long strip MnS inclusions in the steel are reduced due to the formation of Ti4C2S2. Spherical Ti4C2S2 has high hardness and does not deform during high temperature forging, which can improve the impact toughness of steel.

[0017] Ti, Y, and Al will also form a binary or ternary eutectic liquid phase at a relatively low temperature during the cooling process of the molten steel. The appearance of the liquid phase is beneficial to the flow of the molten steel grains to a certain extent when they are initially formed during the forming process, thereby promoting the densification distribution of the grains.

[0018] After the 42CrMo is subjected to nitriding and then oxidation treatment, the surface of the nitrided layer will have the composition of magnetite and possess certain magnetism. A silicon solution is prepared by mixing tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol in a certain proportion. It is deposited in two steps under ultrasonic reaction. First, silica is coated on the outside of magnetite and bonded together by stabilizing the Si - O - Fe chemical bond to obtain a primary deposition layer. Then, due to the introduction of yttrium oxide into the silicon solution, a final deposition layer will be formed due to the existence of stable Si - O - Y chemical bonds, thus completing the deposition of a yttrium - doped modified porous silica layer on the surface of the nitrided layer. Subsequently, in the gaseous titanium tetrachloride atmosphere using the porous and yttrium - doped modified silica layer, titanium tetrachloride will enter the porous silica and undergo cross - linking, hydrolysis, and condensation reactions with the amino groups thereon to form a titanium dioxide cross - linked network. Finally, titanium carbide is formed by high - temperature reduction in a methane - containing reducing atmosphere. Since yttrium is doped in the silica layer, when titanium carbide is formed, yttrium can make the primary titanium carbide dendrites become fine, increase the dendrite spacing, and increase the amount of slender eutectic titanium carbide to obtain ultrafine - grained titanium carbide. The ultrafine - grained titanium carbide increases the interfacial wettability at the yttrium - purified interface, enabling it to be uniformly dispersed in the silica layer and having a high density. When microcracks and residual stresses occur around the ultrafine - grained titanium carbide, it can pin the cracks and consume the fracture energy, thereby improving the toughness of the coating material.

[0019] On the basis of the above - mentioned embodiment, the following improvements are made. The bottom of the middle mold body includes a first vertical surface, a first horizontal surface, a first slope surface, a second horizontal surface, a second slope surface, and a third horizontal surface;

[0020] The top of the lower mold body includes a fourth horizontal surface, a second vertical surface, a third slope surface, a fifth horizontal surface, a fourth slope surface, and a sixth slope surface;

[0021] The first vertical surface, the first horizontal surface, the first slope surface, the second horizontal surface, the second slope surface, and the third horizontal surface and the second vertical surface, the third slope surface, the fifth horizontal surface, the fourth slope surface, and the sixth horizontal surface enclose a first forming area;

[0022] The sixth horizontal surface and the third horizontal surface enclose a third forming area.

[0023] On the basis of the above - mentioned embodiment, the following improvements are made. The top of the rear side wall of the middle mold body is inclined forward, and a convex forming body is provided at the top of the rear side of the middle mold body.

[0024] On the basis of the above - mentioned embodiment, the following improvements are made. The top of the middle mold body includes a seventh horizontal surface, a third vertical surface, a first arc surface, a fourth slope surface, a fourth vertical surface, and a fifth slope surface;

[0025] The bottom of the upper die body includes an eighth horizontal plane, a fourth vertical plane, an arc surface II, a sixth slope surface, a fifth vertical plane, and a seventh slope surface;

[0026] The seventh horizontal plane, the third vertical plane, the arc surface I, the fourth slope surface, the fourth vertical plane, and the fifth slope surface and the eighth horizontal plane, the fourth vertical plane, the arc surface II, the sixth slope surface, the fifth vertical plane, and the seventh slope surface enclose a forming area II.

[0027] Based on the above embodiments, the following improvements are made. The sixth slope surface, the fifth vertical plane, and the seventh slope surface are arranged on the formed body.

[0028] Based on the above embodiments, the following improvements are made. The rear side surface of the guide body and the fourth horizontal plane form a positioning area I, the seventh horizontal plane and the top of the guide body form a positioning area II, and the second horizontal plane and the rear side wall of the middle die body form a positioning area III.

[0029] A processing method for bending and forming a multi-folded angle workpiece. The processing steps of the middle die body are as follows:

[0030] Smelting

[0031] Smelt using the material of claim 1, and add 0.013 - 0.023 parts of alloy steel modification agent when tapping. The alloy steel modification agent includes 32 - 45 parts of Al2O3, 26 - 31 parts of Al, 16 - 28 parts of CaF2, 5 - 15 parts of MgO, and 2 - 5 parts of LaNi5 to obtain a forging blank of the middle die body material;

[0032] Forging and stress relief annealing treatment of the forging

[0033] Heat the obtained forging blank to 1250 - 1450 °C for forging, and the final forging temperature is 950 - 970 °C to obtain a forging; anneal the obtained forging in an annealing furnace, the annealing temperature is 680 - 750 °C, the annealing time is 4 - 5 h, cool it to 200 - 300 °C in the annealing furnace, and then air-cool it to room temperature after holding for 0.6 - 1.2 h;

[0034] Initial processing and heat treatment of the forging

[0035] The forging is machined on a machine tool into the primary shape of the mold, leaving a margin of 1.5 mm on each surface; the mold obtained by machining is first heated to 530 - 550 °C and held for 3 - 4 h, then heated to 750 - 800 °C and held for 1 - 2 h, then heated to 940 - 960 °C, quenched after holding for 30 - 45 min, quenched in oil, and after cooling, it is further subjected to cryogenic treatment. The temperature of the cryogenic treatment is -220 °C to -230 °C, held for 1 - 2 h, restored to room temperature in air, tempered once, the tempering temperature is 130 - 140 °C, cooled to room temperature and left for 1 - 1.5 h, and then tempered a second time, the tempering temperature is 150 - 170 °C;

[0036] Deep processing and machining center treatment of the middle mold body

[0037] Remove the oxide layer on the surface of the treated mold, and assemble it onto a grinding machine for grinding. Leave a margin of 0.7 - 1 mm on each surface. After placing it for at least 1 day, grind the other surfaces except the arc surface again to the required dimensions; place the workpiece obtained by deep processing into the machining center, and use a milling cutter to mill the arc surface of the mold, removing a margin of 0.7 - 1 mm.

[0038] Based on the above embodiments, the following improvements are made: the preparation process of the Ti - xY wear - resistant alloy layer:

[0039] The upper mold body made of 42CrMo as the raw material is subjected to nitriding and then oxidation treatment. Prepare a deposition solution by mixing tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol in a ratio of 1:4 - 5:7 - 8:3 - 4. Place the heat - treated upper mold body in 25 - 35 times the amount of the deposition solution, and carry out ultrasonic reaction at 45 - 60 Hz for 2 - 4 h. Then add 0.02 - 0.08 times the amount of nano - yttrium oxide of tetraethoxysilane, and carry out ultrasonic reaction at 45 - 60 Hz for 2 - 4 h. Take it out and wash it 2 times with 250 mL of pure water, wash it 2 times with 180 mL of 95% ethanol, dry it at 85 - 95 °C for 4 - 6 h, then place it in a reactor, evacuate to make the pressure reach 3.5 - 4.5 MPa, introduce 0.05 - 0.12 times the amount of gaseous titanium tetrachloride of tetraethoxysilane, raise the temperature of the reactor to 330 - 350 °C, evacuate again to make the pressure reach 3.5 - 4.5 MPa, then introduce a mixed reducing gas until the pressure reaches 75 - 95 MPa, and then keep the temperature of the upper mold body at 800 - 1200 °C and deposit for 5 - 8 h.

[0040] Based on the above embodiments, the following improvements are made: the mixed reducing gas includes one or more of hydrogen and silane in addition to methane.

[0041] A forming method for a multi - angled workpiece, and the forming process is as follows:

[0042] First, place the sheet through the first positioning area inside the first forming area. Press down the upper die body to drive the middle die body downward. With the cooperation of the first vertical surface, the first horizontal surface, the first slope surface, the second horizontal surface, the second slope surface, and the third horizontal surface with the fourth horizontal surface, the second vertical surface, the third slope surface, the fifth horizontal surface, the fourth slope surface, and the sixth horizontal surface of the lower die body, form other sections of the sheet except for the U-shaped folding structure;

[0043] Subsequently, the upper die body resets, and the middle die body ascends and resets under the action of the spring through the guide body and the installation groove;

[0044] Finally, transfer the sheet from the first forming area to the second positioning area of the second forming area. The upper die body moves downward again to fold out the initial form of the U-shaped folding structure here. During the process of folding out the initial form of the U-shaped folding structure, position the sheet that has already folded out the initial form of the U-shaped folding structure last time through the third positioning area. When folding out the initial form of the U-shaped folding structure at the top of the middle die body, fold out the final form of the initial U-shaped folding structure at the third positioning area simultaneously. Description of the Drawings

[0045] Figure 1 Schematic diagram of the overall structure of the present invention Figure 1 ;

[0046] Figure 2 Schematic diagram of the overall structure of the present invention Figure 2 ;

[0047] Figure 3 Schematic diagram of the overall structure of the present invention Figure 3 ;

[0048] Figure 4 Schematic diagram of the overall structure of the present invention Figure 4 ;

[0049] Figure 5 Schematic diagram of the overall structure of the present invention Figure 5 ;

[0050] Figure 6 Schematic diagram of the nine-fold workpiece of the present invention.

[0051] In the figure: 10. Upper die body; 20. Lower die body; 30. Middle die body; 31. Forming body; 40. Installation groove; 50. Spring; 60. Guide body; 70. Socket; 80. First forming area; 90. Second forming area; 100. Third forming area. Detailed Embodiments

[0052] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0053] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0054] Embodiment 1

[0055] As Figures 1 to 5 shown, a multi-folded angle workpiece bending and forming die includes an upper die body 10, a lower die body 20 and a middle die body 30. An installation groove 40 is arranged on the lower die body 20, a spring 50 is arranged inside the installation groove 40, a guiding body 60 which is slidably matched with the installation groove 40 is arranged at the bottom of the middle die body 30, and a socket 70 for installing the spring 50 is arranged on the upper part of the guiding body 60. A forming area one 80 is arranged on one side where the lower die body 20 and the middle die body 30 face each other, and a forming area two 90 is arranged on one side where the middle die body 30 and the upper die body 10 face each other.

[0056] The bottom of the middle die body 30 includes a first vertical surface, a first horizontal surface, a first slope surface, a second horizontal surface, a second slope surface and a third horizontal surface;

[0057] The top of the lower die body 20 includes a fourth horizontal surface, a second vertical surface, a third slope surface, a fifth horizontal surface, a fourth slope surface and a sixth horizontal surface;

[0058] The first vertical surface, the first horizontal surface, the first slope surface, the second horizontal surface, the second slope surface and the third horizontal surface and the second vertical surface, the third slope surface, the fifth horizontal surface, the fourth slope surface and the sixth horizontal surface enclose the forming area one 80. The rear side surface of the guiding body 60 and the fourth horizontal surface form a positioning area one. The sixth horizontal surface and the third horizontal surface enclose a forming area three 100. The second horizontal surface and the rear side wall of the middle die body 30 form a positioning area three.

[0059] The top of the rear side wall of the middle die body 30 is inclined forward, and a forming body 31 which protrudes upward is arranged at the top of the rear side of the middle die body 30.

[0060] The top of the middle die body 30 includes a seventh horizontal surface, a third vertical surface, a first arc surface, a fourth slope surface, a fourth vertical surface and a fifth slope surface;

[0061] The bottom of the upper die body 10 includes an eighth horizontal surface, a fourth vertical surface, a second arc surface, a sixth slope surface, a fifth vertical surface and a seventh slope surface;

[0062] The seventh horizontal plane, the third vertical plane, the first arc surface, the fourth slope surface, the fourth vertical plane, and the fifth slope surface, together with the eighth horizontal plane, the fourth vertical plane, the second arc surface, the sixth slope surface, the fifth vertical plane, and the seventh slope surface, enclose a forming area two 90. The sixth slope surface, the fifth vertical plane, and the seventh slope surface are disposed on the formed body 31. The top of the seventh horizontal plane and the guiding body 60 form a positioning area two.

[0063] By placing the sheet through the positioning area one inside the forming area one 80, the upper die body 10 is pressed down to drive the middle die body 30 to move downward. With the cooperation of the first vertical plane, the first horizontal plane, the first slope surface, the second horizontal plane, the second slope surface, and the third horizontal plane with the fourth horizontal plane, the second vertical plane, the third slope surface, the fifth horizontal plane, the fourth slope surface, and the sixth slope surface of the lower die body 20, other section structures except the U-shaped folding structure are formed on the sheet. Subsequently, the upper die body 10 is reset, and the middle die body 30 moves upward and resets under the action of the spring 50 through the guiding body 30 and the installation groove 40, transferring the sheet from the forming area one 80 to the positioning area two 90 of the forming area two. The upper die body 10 moves downward again to fold the initial shape of the U-shaped folding structure here. During the process of folding the initial shape of the U-shaped folding structure, the sheet on which the initial shape of the U-shaped folding structure has been folded last time is positioned through the positioning area three. When the initial shape of the U-shaped folding structure is folded on the top of the middle die body 30, the final shape of the initial U-shaped folding structure at the positioning area three is folded simultaneously. The bending process is efficient and easy to operate and process.

[0064] Among them, the components and mass percentages of the middle die body 30 are: 0.17 parts of C, 0.186 parts of Si, 5.44 parts of Mn, 7.13 parts of Cr, 4.15 parts of Ni, ≤0.02 parts of P, ≤0.02 parts of S, 0.021 parts of Nb, 0.012 parts of Y, 0.072 parts of Ti, 0.08 parts of B, and the balance is Fe and impurities;

[0065] Among them: Ti = 0.21 * (Nb + Y) + 0.34 * (C + S) = 0.21 * (0.021 + 0.012) + 0.34 * (0.17 + 0.02) = 0.072;

[0066] Among them: Si = 0.21 * B + 0.015 * (Ni + Cr) = 0.21 * 0.08 + 0.015 *

[0067] (4.15 + 7.13) = 0.186.

[0068] Example 2

[0069] The components and mass percentages of the middle die body 30 are as follows: 0.19 parts of C, 0.22 parts of Si, 5.87 parts of Mn, 8.15 parts of Cr, 5.15 parts of Ni, ≤0.02 parts of P, ≤0.02 parts of S, 0.028 parts of Nb, 0.016 parts of Y, 0.081 parts of Ti, 0.08 parts of B, and the balance is Fe and impurities;

[0070] Among them: Ti = 0.21*(Nb + Y)+0.34*(C + S)=0.21*(0.028 + 0.016)+0.34*(0.19 + 0.02)=0.081;

[0071] Among them: Si = 0.21*B + 0.015*(Ni + Cr)=0.21*0.08 + 0.015*

[0072] (5.15 + 8.15)=0.22.

[0073] Example 3

[0074] The components and mass percentages of the middle die body 30 are as follows: 0.32 parts of C, 0.265 parts of Si, 7.65 parts of Mn, 9.54 parts of Cr, 6.15 parts of Ni, ≤0.02 parts of P, ≤0.02 parts of S, 0.037 parts of Nb, 0.016 parts of Y, 0.127 parts of Ti, 0.14 parts of B, and the balance is Fe and impurities;

[0075] Among them: Ti = 0.21*(Nb + Y)+0.34*(C + S)=0.21*(0.037 + 0.016)+0.34*(0.32 + 0.02)=0.127;

[0076] Among them: Si = 0.21*B + 0.015*(Ni + Cr)=0.21*0.14 + 0.015*

[0077] (6.15 + 9.54)=0.265.

[0078] The hardnesses of the dies obtained through the above three examples by the same process are HRC59, HRC61, and HRC58 respectively, and there are no cracks after magnetic particle flaw detection. After being processed and used 20300 times, 21500 times, and 20900 times, the die body is still in normal use.

[0079] In the above example, the following improvements are made. The alloy steel modifier includes 45 parts of Al2O3, 26 parts of Al, 16 parts of CaF2, 10 parts of MgO, and 3 parts of LaNi5.

[0080] In the above embodiments, the following improvements are made. The alloy steel modifier comprises 32 parts of Al2O3, 31 parts of Al, 19 parts of CaF2, 13 parts of MgO, and 5 parts of LaNi5.

[0081] During tapping, adding the above components can deoxidize and modify the top ladle slag, improve the desulfurization rate of molten steel, use calcium carbide and aluminum particles for diffusion deoxidation, and promote the rapid melting and uniform deoxidation of the top slag. It is easy to obtain a Mg2NiLa, Mg2Ni, MgNi2 three-phase alloy with good thermal stability. Given that the chemical property of Ti element is extremely active and it is easy to react with O, N, etc. in molten steel, in order to stabilize the recovery rate of Ti element, Ti microalloying is selected before tapping.

[0082] Example 4: On the basis of the above embodiments, the following improvements are made: the manufacturing process of the upper die body 30, and the preparation steps are as follows: subject the lower die base 10, lower die body 20, and upper die body 60 made of 42CrMo to nitriding and then oxidation treatment. Prepare a deposition solution by mixing tetraethoxysilane, 28% by mass of ammonia water, pure water, and absolute ethanol in a ratio of 1:4:7:3. Place the heat-treated lower die base 10, lower die body 20, and upper die body 60 in 25 - 35 times the amount of the deposition solution, and perform ultrasonic reaction at 45 - 60 Hz for 2 - 4 h. Then add 0.03 times the amount of nano-yttrium oxide of tetraethoxysilane, and perform ultrasonic reaction at 45 - 60 Hz for 2 - 4 h. Take out and wash 2 times with 250 mL of pure water, wash 2 times with 180 mL of 95% ethanol, dry at 85 - 95 °C for 4 - 6 h, then place it in a reactor, evacuate to make the pressure reach 3.5 - 4.5 MPa, introduce 0.05 - 0.12 times the amount of gaseous titanium tetrachloride of tetraethoxysilane, raise the temperature of the reactor to 345 °C, evacuate again to make the pressure reach 3.5 - 4.5 MPa, then introduce a mixed reducing gas until the pressure reaches 75 - 95 MPa, and then deposit at 1150 °C for 5 - 8 h with the temperatures of the lower die base 10, lower die body 20, and upper die body 60 to obtain a Ti-xY wear-resistant alloy layer.

[0083] Example 5: The following improvements are made on the basis of the above embodiments: the manufacturing process of the upper die body 30, and the preparation steps are as follows: subject the upper die body 30 with 42CrMo as the raw material to nitriding and then oxidation treatment, prepare a deposition solution by mixing tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol in a ratio of 1:5:8:4, place the heat-treated upper die body 30 in 25 - 35 times the amount of the deposition solution, perform ultrasonic reaction at 45 - 60 Hz for 2 - 4 h, then add 0.05 times the amount of nano-yttrium oxide of tetraethoxysilane, perform ultrasonic reaction at 45 - 60 Hz for 2 - 4 h, take it out and wash it 2 times with 250 mL of pure water, wash it 2 times with 180 mL of 95% ethanol, dry it at 85 - 95 °C for 4 - 6 h, then place it in a reactor, evacuate to make the pressure reach 3.5 - 4.5 MPa, introduce 0.05 - 0.12 times the amount of gaseous titanium tetrachloride of tetraethoxysilane, raise the temperature of the reactor to 340 °C, evacuate again to make the pressure reach 3.5 - 4.5 MPa, then introduce a mixed reducing gas until the pressure reaches 75 - 95 MPa, and then deposit for 7 h at a temperature of about 1000 °C of the upper die body 30 to obtain a Ti-xY wear-resistant alloy layer.

[0084] Example 6: The following improvements are made on the basis of the above embodiments: the manufacturing process of the upper die body 30, and the preparation steps are as follows: subject the upper die body 30 with 42CrMo as the raw material to nitriding and then oxidation treatment, prepare a deposition solution by mixing tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol in a ratio of 1:4:8:3, place the heat-treated upper die body 30 in 25 - 35 times the amount of the deposition solution, perform ultrasonic reaction at 45 - 60 Hz for 2 - 4 h, then add 0.04 times the amount of nano-yttrium oxide of tetraethoxysilane, perform ultrasonic reaction at 45 - 60 Hz for 2 - 4 h, take it out and wash it 2 times with 250 mL of pure water, wash it 2 times with 180 mL of 95% ethanol, dry it at 85 - 95 °C for 4 - 6 h, then place it in a reactor, evacuate to make the pressure reach 3.5 - 4.5 MPa, introduce 0.05 - 0.12 times the amount of gaseous titanium tetrachloride of tetraethoxysilane, raise the temperature of the reactor to 350 °C, evacuate again to make the pressure reach 3.5 - 4.5 MPa, then introduce a mixed reducing gas until the pressure reaches 75 - 95 MPa, and then deposit for 7 h at a temperature of about 950 °C of the upper die body 30 to obtain a Ti-xY wear-resistant alloy layer.

[0085] Comparative Example 1: Only perform nitriding and then oxidation treatment.

[0086] Comparative Example 2: The upper die body 30 made of 42CrMo as the raw material was subjected to nitriding and then oxidation treatment. A deposition solution was prepared by mixing tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol in a ratio of 1:4 - 5:7 - 8:3 - 4. The heat-treated upper die body 30 was placed in 25 - 35 times the amount of the deposition solution, and ultrasonic reaction was carried out at 45 - 60 Hz for 2 - 4 h. After taking it out, it was washed twice with 250 mL of pure water and twice with 180 mL of 95% ethanol, and dried at 85 - 95 °C for 4 - 6 h. Subsequently, it was placed in a reactor, evacuated to a pressure of 3.5 - 4.5 MPa, and gaseous titanium tetrachloride 0.05 - 0.12 times the amount of tetraethoxysilane was introduced. The temperature of the reactor was raised to 330 - 350 °C, and then evacuated again to a pressure of 3.5 - 4.5 MPa. Subsequently, a mixed reducing gas was introduced until the pressure reached 75 - 95 MPa. Then, with the temperature of the upper die body 30 being 800 - 1200 °C, deposition was carried out for 7 h.

[0087] Comparative Example 3: The upper die body 30 made of 42CrMo as the raw material was subjected to nitriding and then oxidation treatment. A deposition solution was prepared by mixing tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol in a ratio of 1:4 - 57 - 8:3 - 4. The heat-treated upper die body 30 was placed in 25 - 35 times the amount of the deposition solution, and ultrasonic reaction was carried out at 45 - 60 Hz for 2 - 4 h, and ultrasonic reaction was carried out at 45 - 60 Hz for 2 - 4 h. After taking it out, it was washed twice with 250 mL of pure water and twice with 180 mL of 95% ethanol, and dried at 85 - 95 °C for 4 - 6 h. Subsequently, it was placed in a reactor, evacuated to a pressure of 3.5 - 4.5 MPa, and then a mixed reducing gas was introduced until the pressure reached 75 - 95 MPa. A titanium wire was introduced and heated to about 2000 °C, and then with the temperature of the upper die body 30 being 800 - 1200 °C, deposition was carried out for 6 h.

[0088] The performance analysis results of the density and wear resistance of the Ti - xY wear-resistant alloy layer using Examples 1 to 3 and Comparative Examples 1 to 3 of the present invention are given as follows:

[0089]

[0090] The hardnesses of the upper die bodies 30 obtained by the above three examples through the same process are HRC58, HRC69, and HRC57 respectively, and there are no cracks detected by magnetic particle flaw detection. After being processed and used 18900 times, 19200 times, and 18700 times, the upper die bodies 30 are still in normal use.

[0091] As described above, only the preferred specific embodiments of the present invention are provided, but the protection scope of the present invention is not limited thereto. The substitution may be the substitution of some structures, devices, and method steps, or a complete technical solution. Any equivalent substitution or change made according to the technical solution and inventive concept of the present invention should be covered within the protection scope of the present invention.

Claims

1. A folding die for forming a multi-folded workpiece, characterized in that, It includes an upper die body (10), a lower die body (20) and a middle die body (30). An installation groove (40) is arranged on the lower die body (20), and a spring (50) is arranged inside the installation groove (40). A guiding body (60) that is slidably fitted inside the installation groove (40) is arranged at the bottom of the middle die body (30), and a socket (70) for installing the spring (50) is arranged at the upper part of the guiding body (60). A first forming area (80) is arranged on one side where the lower die body (20) and the middle die body (30) face each other, and a second forming area (90) is arranged on one side where the middle die body (30) and the upper die body (10) face each other; The components and mass percentages of the middle die body (30) are as follows: 0.17 - 0.52 parts of C, 0.17 - 0.31 parts of Si, 5.44 - 8.15 parts of Mn, 7.13 - 11.58 parts of Cr, 4.15 - 6.55 parts of Ni, ≤0.02 parts of P, ≤0.02 parts of S, 0.021 - 0.038 parts of Nb, 0.012 - 0.017 parts of Y, 0.07 - 0.23 parts of Ti, 0.08 - 0.14 parts of B, and the balance is Fe and impurities; Wherein: Ti = 0.21(Nb + Y) + 0.34(C + S); Wherein: Si = 0.21B + 0.015(Ni + Cr); A Ti - xY wear - resistant alloy layer is arranged in the forming area of the upper die body (10); The bottom of the middle die body (30) includes a first vertical surface, a first horizontal surface, a first slope surface, a second horizontal surface, a second slope surface and a third horizontal surface; The top of the lower die body (20) includes a fourth horizontal surface, a second vertical surface, a third slope surface, a fifth horizontal surface, a fourth slope surface and a sixth horizontal surface; The first vertical surface, the first horizontal surface, the first slope surface, the second horizontal surface, the second slope surface and the third horizontal surface and the second vertical surface, the third slope surface, the fifth horizontal surface, the fourth slope surface and the sixth horizontal surface enclose the first forming area (80); The sixth horizontal surface and the third horizontal surface enclose the third forming area (100); The top of the rear side wall of the middle die body (30) is inclined forward, and a forming body (31) that protrudes upward is arranged at the top of the rear side of the middle die body (30); The top of the middle die body (30) includes a seventh horizontal surface, a third vertical surface, a first arc surface, a fourth slope surface, a fourth vertical surface and a fifth slope surface; The bottom of the upper die body (10) includes an eighth horizontal surface, a fourth vertical surface, a second arc surface, a sixth slope surface, a fifth vertical surface and a seventh slope surface; The seventh horizontal surface, the third vertical surface, the first arc surface, the fourth slope surface, the fourth vertical surface and the fifth slope surface and the eighth horizontal surface, the fourth vertical surface, the second arc surface, the sixth slope surface, the fifth vertical surface and the seventh slope surface enclose the second forming area (90).

2. The bending and forming die for a multi-folded angle workpiece according to claim 1, characterized in that, The sixth slope surface, the fifth vertical surface and the seventh slope surface are arranged on the forming body (31).

3. The bending and forming die for a multi-folded angle workpiece according to claim 2, characterized in that, The rear side of the guiding body (60) and the fourth horizontal plane form positioning area one. The seventh horizontal plane and the top of the guiding body (60) form positioning area two. The second horizontal plane and the rear side wall of the middle die body (30) form positioning area three.

4. The multi-fold angle workpiece bending and forming die according to claim 1, wherein, The processing steps of the middle die body (30) are as follows: (1) Smelting Smelting with the material of claim 1, adding 0.013 - 0.023 parts of alloy steel modifier during tapping. The alloy steel modifier includes 32 - 45 parts of , 26 - 31 parts of Al, 16 - 28 parts of , 5 - 15 parts of MgO and 2 - 5 parts of , and obtaining a forging blank of the material for the middle mold body (30); (2) Forging and stress relief annealing treatment of forgings Heat the obtained forging blank to 1250 - 1450 °C for forging, and the final forging temperature is 950 - 970 °C to obtain a forging; anneal the obtained forging in an annealing furnace, with the annealing temperature of 680 - 750 °C, the annealing time of 4 - 5 h, cool it in the annealing furnace to 200 - 300 °C, keep it warm for 0.6 - 1.2 h and then air-cool to room temperature; (3) Rough machining and heat treatment of forgings Machine the forging on a machine tool into the primary shape of the mold, leaving a margin of 1.5 mm on each surface; heat the mold obtained by machining to 530 - 550 °C first and keep it warm for 3 - 4 h, then heat it to 750 - 800 °C and keep it warm for 1 - 2 h, then heat it to 940 - 960 °C, keep it warm for 30 - 45 min and then quench it, oil quench, after cooling, perform cryogenic treatment, the temperature of cryogenic treatment is -220 °C to -230 °C, keep it for 1 - 2 h, restore it to room temperature in the air, perform one-time tempering, the tempering temperature is 130 - 140 °C, cool it to room temperature and place it for 1 - 1.5 h, then perform secondary tempering, the tempering temperature is 150 - 170 °C; (4) Deep processing and machining center treatment of the middle die body (30) Remove the oxide layer on the surface of the processed mold, and assemble it on a grinding machine for grinding, leaving a margin of 0.7 - 1 mm on each surface. After placing it for at least 1 day, grind the other surfaces except the arc surface again to the required size; put the workpiece obtained by deep processing into a machining center, and use a milling cutter to mill the arc surface of the mold, removing a margin of 0.7 - 1 mm.

5. A multi-folded angle workpiece bending and forming die according to claim 1, characterized in that, The preparation process of the Ti-xY wear-resistant alloy layer: Perform nitriding and oxidation treatment on the upper die body (10) with 42CrMo as the raw material. Prepare a deposition solution by mixing tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol in proportion. Place the heat-treated upper die body (10) in 25 - 35 times the amount of the deposition solution, perform ultrasonic reaction at 45 - 60 Hz for 2 - 4 h, then add 0.02 - 0.08 times the amount of nano-yttrium oxide of tetraethoxysilane, perform ultrasonic reaction at 45 - 60 Hz for 2 - 4 h, take it out and wash it 2 times with 250 mL of pure water, wash it 2 times with 180 mL of 95% ethanol, dry it at 85 - 95 °C for 4 - 6 h, then place it in a reactor, evacuate to make the pressure reach 3.5 - 4.5 MPa, introduce 0.05 - 0.12 times the amount of gaseous titanium tetrachloride of tetraethoxysilane, raise the temperature of the reactor to 330 - 350 °C, evacuate again to make the pressure reach 3.5 - 4.5 MPa, then introduce a mixed reducing gas until the pressure reaches 75 - 95 MPa, and then keep the temperature of the upper die body (10) at 800 - 1200 °C for deposition for 5 - 8 h.

6. The bending and forming die for a multi-folded angle workpiece according to claim 5, characterized in that, The mixed reducing gas includes one or more of hydrogen and silane in addition to methane.

7. A forming method for a multi-folded angle workpiece, using the multi-folded angle workpiece bending and forming die as described in claim 3, characterized in that, The forming process is as follows: First, place the sheet through the first positioning area inside the first forming area (80). Drive the middle die body (30) to move downward by pressing down the upper die body (10). With the cooperation of the first vertical surface, the first horizontal surface, the first slope surface, the second horizontal surface, the second slope surface, and the third horizontal surface and the fourth horizontal surface, the second vertical surface, the third slope surface, the fifth horizontal surface, the fourth slope surface, and the sixth slope surface of the lower die body (20), form other section structures of the sheet except for the U-shaped folding structure. Subsequently, the upper die body (10) resets, and the middle die body (30) moves upward and resets under the action of the spring (50) through the guide body (60) and the installation groove (40). Finally, transfer the sheet from the first forming area (80) to the second positioning area of the second forming area (90). The upper die body (10) moves downward again to fold out the initial shape of the U-shaped folding structure here. During the process of folding out the initial shape of the U-shaped folding structure, position the workpiece that has already folded out the initial shape of the U-shaped folding structure last time through the third positioning area. When folding out the initial shape of the U-shaped folding structure at the top of the middle die body (30), fold out the final shape of the initial U-shaped folding structure at the third positioning area simultaneously.

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