Die capable of achieving rapid forming and quenching therein

Abstract

The present invention provides a die capable of achieving rapid forming and quenching therein. The die includes an upper die, a blank holder and a lower die, where the upper die is composed of an internal solid die core and a thin-walled skin. Grooves in communication with each other are disposed between the internal solid die core and the thin-walled skin. In a forming stage, the grooves are not filled or filled with a heat insulating material such as a gas; and in a quenching stage, a low-temperature medium is introduced into the grooves. The die can be used to achieve rapid forming and quenching of metal materials of different types and thicknesses.

Claims

1. A die configured to achieve rapid forming and quenching therein, comprising an internal solid die core, an upper thin-walled skin, a blank holder and a lower die, wherein the internal solid die core and the upper thin-walled skin move up and down in the blank holder after being combined; the lower surface of the internal solid die core is provided with a plurality of upper grooves, and the upper grooves are separated from each other through vertical ribs integrated with the internal solid die core and are in communication with each other; the upper surface of the internal solid die core is provided with an upper leading-in hole and an upper leading-out hole which lead to the upper grooves, the upper leading-in hole is used for injecting a low-temperature medium into the upper grooves, and the leading-out hole is used for leading out the low-temperature medium after heat exchange; the surface of the upper groove is covered with an upper thin-walled skin, which is fixed on the internal solid die core; the lower surface of the upper thin-walled skin is attached to the upper surface of a hot metal slab, and the hot metal slab is quickly cooled and quenched after the forming is completed; wherein the inner surface of the lower die is provided with a lower groove, and the lower groove is arranged in the same manner as the upper groove, the surface of the lower groove is covered with a lower thin-walled skin, which is fixed on the inner surface of the lower die; the lower die is provided with a lower leading-in hole and a lower leading-out hole which lead to the lower groove, the lower leading-in hole is used for injecting a low-temperature medium into the lower groove, and the lower leading-out hole is used for leading out the low-temperature medium after heat exchange; in the forming stage, a gas with certain pressure is introduced into the groove between the thin-walled skin and the solid die core; after the forming is completed, the lower surface of the upper thin-walled skin and the upper surface of the lower thin-walled skin are simultaneously in contact with the hot metal slab, and the surface of the hot metal slab is rapidly cooled to complete the quenching; wherein the shape and dimensions of the outer surface of the thin-walled skin are the same as those of a part to be formed, and the selected material is a stainless steel plate, a superalloy plate or a titanium alloy plate, with a thickness of 0.2-0.5 mm; and the thin-walled skin is in close contact with the vertical ribs of the internal solid die core, and is not deformed during contact with the hot metal slab.

2. The die according to claim 1, wherein the depth of the groove is 2-10 mm, and the distance between adjacent vertical ribs is 5-30 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic structural view of a die capable of achieving rapid forming and quenching therein according to the present invention;

(2) FIGS. 2A-2D are views showing the working principle of a die capable of achieving rapid forming and quenching therein according to the present invention;

(3) FIG. 3 is a schematic structural view of a second die of a die capable of achieving rapid forming and quenching therein according to the present invention; and

(4) FIGS. 4A-4D are views showing the working principle of a second die of a die capable of achieving rapid forming and quenching therein according to the present invention.

(5) In the figure: 1. internal solid die core, 2. upper leading-in hole, 3. upper thin-walled skin, 4. vertical rib, 5. upper leading-out hole, 6. upper groove, 7. low-temperature medium, 8. blank holder, 9. hot metal slab, 10. lower die, 11. initial filling gas; 12. lower groove; 13. lower thin-walled skin, 14. lower leading-in hole, 15. lower leading-out hole.

DETAILED DESCRIPTION

(6) The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings and technical solutions.

Embodiment 1

(7) With reference to FIGS. 1 and 2, in a die capable of achieving rapid forming and quenching therein, (1) a forming die includes an upper die and a lower die, where the lower die has a conventional overall structure; (2) the upper die has a combined structure, which is composed of a thin-walled skin and an internal solid die core, and the thin-walled skin closely coats the internal solid die core; (3) the shape and dimensions of the outer surface of the thin-walled skin are the same as those of a part; (4) the surface of the internal solid die core is provided with vertical ribs and grooves communicated with each other, and a specific channel is formed after the thin-walled skin is in contact with the grooves; (5) the internal solid die core is provided with a medium leading-in hole and a leading-out hole, which are connected to the channel formed by the skin and the grooves.

(8) The working process of the above die capable of achieving rapid forming and quenching therein is carried out according to the following steps:

(9) Step 1: according to the material type, complexity, precision requirements for a metal sheet part to be formed, select a metal sheet of a corresponding type and thickness as a skin, and use a slab made of a corresponding material as a solid die core.

(10) Step 2: prepare the internal solid die core and machine a groove on the surface thereof, and machine a leading-in hole and a leading-out hole on the side wall thereof.

(11) Step 3: prepare a thin-walled skin slab into a thin-walled skin matching the internal solid die core.

(12) Step 4: connect the thin-walled skin to the internal solid die core, to form a combined forming die.

(13) Step 5: rapidly place the heated metal slab onto the forming die, and close the die to complete the forming of the part;

(14) Step 6: keep the die closed, and quickly introduce a low-temperature medium into a channel composed of the thin-walled skin and the internal solid die core.

(15) Step 7: after a die assembly state is maintained for a certain period of time, open the forming die, and take out the formed part.

Embodiment 2

(16) With reference to FIGS. 3 and 4, in another die capable of achieving rapid forming and quenching therein, (1) a forming die includes an upper die and a lower die, where the upper die and the lower die have a combined structure; (2) the upper die and the lower die are each composed of a thin-walled skin and an internal solid die core, and the thin-walled skin closely coats the internal solid die core; (3) the shape and dimensions of the outer surface of the thin-walled skin are the same as those of a part; (4) the surface of the internal solid die core is provided with vertical ribs and grooves communicated with each other, and a specific channel is formed after the thin-walled skin is in contact with the grooves; (5) the internal solid die core is provided with a medium leading-in hole and a leading-out hole, which are connected to the channel formed by the skin and the grooves.

(17) The working process of the above die capable of achieving rapid forming and quenching therein is the same as that of Embodiment 1.

(18) The forming die is composed of an upper die and a lower die, and the forming of a metal slab is achieved through the cooperation of the upper die and the lower die, which can cope with the situation in which the shape is complex and it is impossible or difficult to ensure part shape and dimensions accuracy of a part only by the upper die. When the hot metal slab is in close contact with the upper die and the lower die and a low-temperature medium is introduced into the upper die and the lower die for cooling, the hot metal slab will be rapidly cooled by the thin-walled skin being in contact with the upper and lower surfaces of the hot metal slab, and a higher cooling rate can be obtained. Therefore, effective quenching of a metal slab having a wall thickness of 5 mm or more can be achieved.

Embodiment 3

(19) With reference to FIGS. 1 to 4, according to a die capable of achieving rapid forming and quenching therein according to the present invention, in step 1, a thin-walled skin in a combined die adopts a metal sheet that has good thermal conductivity, small heat capacity, high strength and wear resistance, such as a stainless steel plate, a superalloy plate or a titanium alloy plate. The thin-walled skin has a thickness of 0.2-0.5 mm, the thin-walled skin is in close contact with vertical ribs of an internal solid die core and does not deform during contact with the metal slab. Others are the same as those of Embodiment 1 and Embodiment 2.

(20) Since the skin has a small wall thickness and a small heat capacity, in the forming stage, when the hot metal slab is in contact with the skin, the temperature of the skin will rise quickly, but the skin will not conduct away a lot of heat from the hot metal slab, thereby avoiding causing a rapid drop in the temperature of the hot metal slab. The use of the die structure can not only avoid the temperature drop of the hot slab that is caused by the contact with a cold die and affects the forming property, but also avoid the unreasonable temperature distribution caused by the local temperature drop of the hot metal slab. Therefore, the hot metal slab can be deformed under a sufficiently high temperature and a reasonable temperature distribution.

Embodiment 4

(21) With respect to FIGS. 1 to 4, in a die capable of achieving rapid forming and quenching therein according to the present invention, in step 1, an internal solid die core in a combined die is made of ordinary cast iron, a hard plastic or a wood material. Others are the same as those of Embodiment 1 and Embodiment 2.

(22) Since the internal solid die core is not in directly contact with the hot metal slab, serious friction and wear are avoided; and since the internal solid die core is only subjected to contact pressure from the thin-walled skin, the internal solid die core is only required to have a certain compressive strength. Therefore, the internal solid die core can be made of an ordinary cast iron material, and the internal solid die core can also be made of a hard plastic or a wood material in the sample piece pilot stage or when the forming quality is not high. With this die structure, the design and machining cycle of the die can be greatly shortened, and the die manufacturing cost can be greatly reduced.

Embodiment 5

(23) With reference to FIGS. 1 to 4, in a die capable of achieving rapid forming and quenching therein according to the present invention, in step 3, the thin-walled skin slab can be pressed by using a solid core die with vertical ribs on the surface and grooves, and the thin-walled skin slab can also be pressed by using a solid core die where vertical ribs and grooves are machined, thereby obtaining a required thin-walled skin. Others are the same as those of Embodiment 1 and Embodiment 2.

(24) The wall thickness of the skin is only 0.2-0.5 mm, and a thin-walled skin slab can be pressed using the internal solid core die to obtain a required final thin-walled skin. Since the skin is machined by using a sheet slab with a high surface quality, it is only necessary to initially machine the shape of the inner solid core die, and it is no longer necessary to use a precision machining machine and a grinding machine to ensure the surface roughness and the like of the skin. With this die structure, the machining cycle of the die can be greatly shortened, and the die manufacturing cost can be greatly reduced.

Embodiment 6

(25) With reference to FIGS. 1 to 4, in a die capable of achieving rapid forming and quenching therein according to the present invention, in step 4, there is no connection between a thin-walled skin and an internal solid core die, or a vertical rib of the solid core die is provided with a sealing material of 0.5-1.0 mm to achieve a close fit between a groove and the skin. Others are the same as those of Embodiment 1 and Embodiment 2.

(26) Since the thin-walled skin and the internal solid die core have a split combined structure, there is no connection or only simple connection between the two, and the thin-walled skin can be quickly removed from the internal solid die core. With this die structure, it is possible to avoid the waste caused by the need to replace the whole die resulting from by local friction and wear of a die cavity or unreasonable partial design and the like. At the same time, when the thin-walled skin is subjected to friction and wear, has an unsuitable thickness or has an unsuitable material, it is also very easy to replace the thin-walled skin.

Embodiment 7

(27) With reference to FIGS. 1 to 4, in a die capable of achieving rapid forming and quenching therein according to the present invention, in step 5, before the heated metal slab is quickly placed on the forming die, a gas with a certain pressure is introduced into the groove between the thin-walled skin and the solid die core. Others are the same as those of Embodiment 1 and Embodiment 2.

(28) A gas with certain pressure such as air or nitrogen is introduced into the groove between the thin-walled skin and the solid die core. Due to the poor thermal conductivity of the gas, the effective separation between the thin-walled skin and the solid die core can be achieved, the thin-walled skin which is in contact with and heated by the hot slab is prevented from exchanging a lot of heat with the solid die core, thereby ensuring that the heat of the hot slab in the forming stage is no longer transferred in large quantities, avoiding causing a drop in temperature.

Embodiment 8

(29) With reference to FIGS. 1 to 4, in a die capable of achieving rapid forming and quenching therein according to the present invention, in steps 5-7, the original thickness of a metal slab can vary from 0.2 mm to 5.0 mm. Others are the same as those of Embodiment 1 and Embodiment 2.

(30) Since the temperature of the metal slab in the forming stage does not rapidly decrease, and the material has low flow stress and high forming property in a hot state, and the forming of a part with a complex shape and structure can be achieved. Due to the rapid heat exchange between the low-temperature medium and the hot part during the quenching stage, a sufficiently high cooling rate and effective quenching can be achieved. Therefore, this die structure can be used not only for the forming and quenching of a plate with a medium thickness (a thickness of 0.5-5.0 mm), but also for the forming and quenching of a thick plate (with a thickness of 5-20 mm) and a sheet (with a thickness of 0.2-0.5 mm).

Embodiment 9

(31) With reference to FIGS. 1 to 4, in a die capable of achieving rapid forming and quenching therein according to the present invention, in steps 1-4, the material of the thin-walled skin is a stainless steel sheet, a titanium alloy sheet or a superalloy sheet. Others are the same as those of Embodiment 1 and Embodiment 2.

(32) The beneficial effects of this embodiment are that the thin-walled skin can be reasonably selected according to the material type, wall thickness and forming temperature and the like of the formed metal slab. When the metal slab forming temperature is 200-450 C. (such as an aluminum alloy slab), a 304 or 306 stainless steel sheet can be used as the thin-walled skin. When the metal slab forming temperature is 500-900 C. (such as high-strength steel 22MnB5), a TC4 or TA2 titanium alloy sheet or a GH4169 superalloy sheet can be used as a thin-walled skin. With this die structure, the forming of different metal thin-walled parts can be realized, and the range of applicable materials is wide.

Embodiment 10

(33) With reference to FIGS. 1 to 4, in a die capable of achieving rapid forming and quenching therein according to the present invention, in step 6: the die is kept closed, a low-temperature medium is quickly introduced into a channel composed of the thin-walled skin and the internal solid die core 1, such as cold water at 5-20 C. or liquid nitrogen. Others are the same as those of Embodiment 1 and Embodiment 2.

(34) When the metal slab has a smaller wall thickness, ice water with a temperature of 5-10 C. can be introduced into the groove; when the metal slab has a larger wall thickness, cold air with a temperature of 50-100 C. or liquid nitrogen with a temperature of 196 C. can be introduced into the groove. Since the skin has a small wall thickness and a small heat capacity, in the quenching stage, when a low-temperature medium is introduced into the groove between the thin-walled skin and the internal solid die core, the temperature of the thin-walled skin is rapidly lowered. Since the skin is good in thermal conductivity, the heat of the hot metal slab can be quickly transferred to a low-temperature medium on the other side through the thin-walled skin, and the hot metal slab is continuously and quickly cooled as the low-temperature medium flows. The use of the die structure can meet the quenching requirements for metal slabs made of different materials and with different wall thicknesses, and the range of applicable materials and parts is wide.

Embodiment 11

(35) With reference to FIGS. 1 to 4, in a die capable of achieving rapid forming and quenching therein according to the present invention, in step 2, grooves machined on the surface of an internal solid die core have different geometrical dimensions and irregular distributions. Others are the same as those of Embodiment 1 and Embodiment 2.

(36) Since the grooves on the surface of the solid die core are easy to machine, the grooves with specific shapes and geometric dimensions can be machined on the surface of an internal solid core die as needed and arranged as needed, and a low-temperature medium in each groove can pass through identical or different leading-in holes and leading-out holes. With this die structure, different temperature distributions can be achieved in the groove composed of the thin-walled skin and the internal core die during the quenching phase, thereby achieving different cooling rates on the hot metal part, which makes it possible to obtain different mechanical property distributions by flexibly controlling quenching effects of regions on the metal part.