Disclosure of Invention
The invention aims to provide a metal mold for manufacturing a beryllium bronze explosion-proof hammer and a manufacturing method of the beryllium bronze explosion-proof hammer, which aim to solve the problems of low density, large structure and easy jumping block in use in the beryllium bronze explosion-proof hammer produced by the prior casting technology and simultaneously solve the problem of high rejection rate caused by easy cracking of the beryllium bronze explosion-proof hammer produced by the prior forging or casting and forging combined technology.
The invention adopts the following technical scheme:
a method for manufacturing a beryllium bronze explosion-proof hammer utilizes metal casting molding.
The metal casting mold comprises a horizontally-split upper half mold and a lower half mold; an upper casting half cavity is arranged on the upper half mould, a lower casting half cavity corresponding to the upper casting half cavity is correspondingly arranged on the lower half mould, and an explosion-proof hammer head cavity is formed after the upper casting half cavity and the lower casting half cavity are closed; an upper half core is arranged at the center of the top surface of the upper casting mold half cavity, a lower half core is arranged at the center of the bottom surface of the lower casting mold half cavity, and the upper half core and the lower half core are frustum-shaped and have conical tops which are relatively combined to form a hammer eye core; an exhaust passage is arranged on the parting surface of the upper half mould and the lower half mould on the outer side of the explosion-proof hammer head cavity; an upper pressure head is arranged on the upper half mould and is communicated with the upper casting mould half cavity; a material storage cavity is arranged in the center of the lower half mold, and a lower pressure head is arranged at the bottom of the material storage cavity; and a runner is arranged between the material storage cavity and the lower casting half cavity.
Which comprises the following steps:
(a) smelting the beryllium bronze alloy to obtain beryllium bronze alloy liquid;
(b) closing the mold and locking the mold: pouring beryllium bronze alloy liquid into a material storage cavity of the lower half mold within 2-5 seconds, closing the upper half mold and the lower half mold, pressurizing and locking, wherein the applied pressure (N) is not less than the total horizontal projection area (mm) of the explosion-proof hammer cavity2)×(100~170)(MPa);
(c) Pressurizing and solidifying: pushing the beryllium bronze alloy liquid in the storage cavity by using the lower pressure head within 1-3 seconds after the mold locking pressure is added to a set value, enabling the alloy liquid to enter an explosion-proof hammer cavity through a flow channel, increasing the pressure to enable the internal pressure of the beryllium bronze alloy liquid to reach 100-170 MPa, maintaining the pressure for 1-10 seconds, applying downward pressure to the beryllium bronze alloy liquid by using the upper pressure head to enable the part below the upper pressure head to form high pressure of 100-200 MPa for feeding, and keeping the pressure when the bottom surface of the upper pressure head is flush with the top surface of the explosion-proof hammer cavity until the beryllium bronze alloy liquid is completely solidified to obtain a beryllium bronze explosion-proof hammer blank with a pouring channel and a material cake;
(d) cutting off excess materials: the lower pressure head continues to move upwards to separate the pouring channel and the material cake from the beryllium bronze explosion-proof hammer blank, and the pouring channel, the material cake and the beryllium bronze explosion-proof hammer blank are ejected out;
(e) finishing and heat treatment: and carrying out heat treatment on the beryllium bronze explosion-proof hammer blank, and polishing to obtain the beryllium bronze explosion-proof hammer.
In the method, the beryllium bronze alloy comprises the following components in percentage by mass: be 1.8-2.2%, and the balance of Cu.
In the method, the smelting temperature in the step (a) is 1200-1400 ℃. Preferably 1300 deg.c.
In the method, the pouring temperature in the step (b) is 960-
In the method, the pressurizing and locking pressure (N) in the step (b) is more than or equal to the total area (mm) of the horizontal projection of the explosion-proof hammer head cavity2)×170(MPa)。
In the method, the internal pressure of the beryllium bronze alloy liquid in the explosion-proof hammer head cavity in the step (c) is 170 MPa.
In the method, the upper half core is shorter than the lower half core by 3-5 mm.
In the method, a plurality of exhaust passages are uniformly arranged on the outer side of the explosion-proof hammer head cavity.
In the method, each explosion-proof hammer head cavity is connected with two runners, and the two runners are respectively arranged on two sides of the hammer eye core.
In the method, each upper casting mold half cavity is symmetrically provided with upper pressure heads at two sides of an upper half core.
In the method, the number of the explosion-proof hammer head cavities is 4-12, and the explosion-proof hammer head cavities are centrosymmetric by taking the material storage cavity as a center.
The invention has the beneficial effects that:
(1) the hammerhead is formed under high pressure, the density of the hammerhead is high, the crystal grains are uniform and fine, and the density can be improved to 8.76g/cm3Meanwhile, the common defects of shrinkage cavity and looseness in casting are avoided;
(2) the liquid beryllium bronze metal is directly solidified and formed in the cavity without excessive plastic deformation, so that the liquid beryllium bronze metal has no cracking defect;
(3) the inclination directions of the upper half core and the lower half core of the hammer eye core are opposite, and the section of the middle part of the hammer eye formed after butt joint is the smallest, so that the hammer handle can be prevented from falling off; the upper half core is 3-5mm shorter than the lower half core, so that a workpiece is kept on the lower die when the die is opened, and the workpiece is convenient to discharge;
(4) the metal mold is molded, and the molded blank has high surface smoothness and high dimensional precision;
(5) the upper pressure head and the lower pressure head are both cylindrical, the fit clearance between the upper pressure head and the through hole is easy to control uniformly, and interference fit is avoided, so that the effective pressure applied to the molten metal is high;
(6) the die has multiple cavities, indirect pressurizing and filling, direct pressurizing and feeding, strong adaptability to the shape complexity of the hammer head, high production efficiency and wide application range;
(7) cutting processing is not needed, and the material utilization rate is high;
(8) the process has less excess materials. The process yield reaches more than 80 percent.
Detailed Description
The present invention is further described with reference to several embodiments, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the present invention, and the present invention shall be covered thereby.
Example 1
A metal casting mould for manufacturing a beryllium bronze explosion-proof hammer comprises an upper half mould 1 and a lower half mould 2 which are horizontally divided; an upper casting mold half cavity 3 is arranged on the upper half mold 1, a lower casting mold half cavity 4 corresponding to the upper casting mold half cavity 3 is correspondingly arranged on the lower half mold 2, and an explosion-proof hammer head cavity is formed after the upper casting mold half cavity 3 and the lower casting mold half cavity 4 are closed.
The metal casting mold is made of hot-work grinding tool steel and is horizontally divided, and the parting surface of the upper half mold and the parting surface of the lower half mold are positioned on the horizontal central plane of the beryllium bronze explosion-proof hammer head.
An upper half core 5 is arranged at the center of the top surface of the upper casting mold half cavity 3, a lower half core 6 is arranged at the center of the bottom surface of the lower casting mold half cavity 4, and the upper half core 5 and the lower half core 6 are frustum-shaped and have conical tops which are relatively combined to form a hammer eye core. The upper half core 5 is 3-5mm shorter than the lower half core 6. The upper half core and the lower half core are made of H13 steel, the inclination directions of the upper half core and the lower half core are opposite, and the upper half core and the lower half core are in butt joint to form a hammer eye with the smallest middle section and large two end sections so as to prevent the hammer handle from loosening and falling off.
And the bottom of the lower casting mold half cavity is provided with ejector rods 13, the ejector rods 13 are symmetrically arranged on two sides of the lower half core and are connected with an ejection device, the ejection device can adopt a hydraulic cylinder, and when the casting mold is finished and the blank needs to be ejected, the hydraulic cylinder drives the ejector rods to move upwards so as to eject the blank out of the explosion-proof hammer head cavity.
And an exhaust passage 8 is arranged on the parting surface 7 of the upper half type 1 and the lower half type 2 at the outer side of the explosion-proof hammer head cavity. The exhaust passage 8 is provided with a plurality of exhaust passages which are uniformly arranged at the outer side of the explosion-proof hammer head cavity.
An upper pressure head 9 is arranged on the upper half mould 1, and the upper pressure head 9 is communicated with the upper casting mould half cavity 3; a material storage cavity 10 is arranged in the center of the lower half mold 2, and a lower pressure head 11 is arranged at the bottom of the material storage cavity 10; a runner 12 is arranged between the material storage cavity 10 and the lower casting mold half cavity 4. Every two runners 12 are connected to the explosion-proof hammer head die cavity, two runners 12 set up respectively in the both sides of hammer eye core. The lower pressure head can move up and down at the bottom of the storage cavity, so that the volume of the storage cavity is changed to provide pressure, the metal casting mold adopts a lower pressure head to pressurize and indirectly fill the mold, and the upper pressure head and the lower pressure head are used for feeding and solidifying the pressure.
In the metal casting mold, upper pressure heads 9 are symmetrically arranged on two sides of each upper casting mold half cavity 3, which are positioned on the upper half core 5. The number of the explosion-proof hammer head cavities is 4-12 and the explosion-proof hammer head cavities are centrosymmetric by taking the material storage cavity 10 as a center.
The upper pressure head is cylindrical, the diameter of the upper pressure head is 16.0mm, the length of the upper pressure head is 50.0mm, a through hole is formed in the upper casting mold half cavity, the upper pressure head penetrates through the through hole, the upper pressure head is driven by the upper hydraulic press to move up and down in the through hole and apply downward pressure to the beryllium bronze alloy liquid.
The lower pressure head is cylindrical, has the diameter of 139.0mm and the length of 100.0mm, is arranged at the bottom end of the storage cavity, can be directly used as the bottom surface of the storage cavity, can move up and down under the drive of the hydraulic machine to change the size of the storage cavity, presses alloy liquid into the explosion-proof hammer head cavity from the storage cavity, and simultaneously provides pressure.
Example 2
A method for manufacturing a beryllium bronze explosion-proof hammer by using the metal mold in the embodiment 1, which comprises the following steps:
(1) smelting the beryllium bronze alloy to obtain beryllium bronze alloy liquid; the beryllium bronze alloy comprises the following components in percentage by mass: be 1.80% and the balance Cu, Ni-free; the melting temperature is 1200 ℃.
(2) Closing the mold and locking the mold: and (3) pouring the beryllium bronze alloy liquid into the material storage cavity of the lower half mold by gravity for 2-5 seconds, closing the upper half mold and the lower half mold, pressurizing and locking, wherein the pouring temperature is 1200 ℃. The applied pressure (N) is more than or equal to the horizontal projection area (mm) of the whole cavity2) X 100 (MPa); the pressurizing, locking and die assembly is to directly compress the upper and lower dies by utilizing pressurizing equipment. The pressurizing equipment is a hydraulic press, the nominal force of a main cylinder is 6000 kN, the upper extrusion cylinder is 3500kN, and the lower extrusion cylinder is 3500 kN.
(3) Pressurizing and solidifying: and pushing the beryllium bronze alloy liquid in the storage cavity by using the lower pressure head within 1-3 seconds after the mold locking pressure is added to a set value, enabling the alloy liquid to enter an explosion-proof hammer cavity through a flow channel, increasing the pressure to enable the internal pressure of the beryllium bronze alloy liquid to reach 100MPa, keeping the pressure for 1-5 seconds, applying downward pressure to the beryllium bronze alloy liquid by using the upper pressure head to enable the part below the upper pressure head to form high pressure of 100MPa for feeding, and keeping the pressure when the bottom surface of the upper pressure head is flush with the top surface of the explosion-proof hammer cavity until the beryllium bronze alloy liquid is completely solidified to obtain a beryllium bronze explosion-proof hammer blank with a pouring channel and a material cake.
(4) Cutting off excess materials: and the lower pressure head and the ejector rod simultaneously move upwards to eject the beryllium bronze explosion-proof hammer blank with the pouring channel and the material cake, the beryllium bronze explosion-proof hammer blank is transferred to a punching work part, the pouring channel and the material cake are separated from the beryllium bronze explosion-proof hammer blank by using a punching machine, and the beryllium bronze explosion-proof hammer blank is subjected to heat treatment.
(5) Finishing and heat treatment: and carrying out heat treatment on the aluminum bronze explosion-proof hammer blank, and polishing to obtain the beryllium bronze explosion-proof hammer.
Example 3
A method for manufacturing a beryllium bronze explosion-proof hammer by using the metal mold in the embodiment 1, which comprises the following steps:
(1) smelting the beryllium bronze alloy to obtain beryllium bronze alloy liquid; the beryllium bronze alloy comprises the following components in percentage by mass: be 2.00% and the balance Cu, Ni-free; the melting temperature is 1300 ℃.
(2) Closing the mold and locking the mold: and (3) pouring the beryllium bronze alloy liquid into the material storage cavity of the lower half mold by gravity for 2-5 seconds, closing the upper half mold and the lower half mold, pressurizing and locking, wherein the pouring temperature is 1200 ℃. The applied pressure (N) is more than or equal to the horizontal projection area (mm) of the whole cavity2)×160(MPa)。
(3) Pressurizing and solidifying: and pushing the beryllium bronze alloy liquid in the storage cavity by using the lower pressure head within 1-3 seconds after the mold locking pressure is added to a set value, enabling the alloy liquid to enter an explosion-proof hammer cavity through a flow channel, increasing the pressure to enable the internal pressure of the beryllium bronze alloy liquid to reach 160MPa, keeping the pressure for 1-10 seconds, applying downward pressure to the beryllium bronze alloy liquid by using the upper pressure head to enable the part below the upper pressure head to form 200MPa high pressure for feeding, and keeping the pressure when the bottom surface of the upper pressure head is flush with the top surface of the explosion-proof hammer cavity until the beryllium bronze alloy liquid is completely solidified to obtain a beryllium bronze explosion-proof hammer blank with a pouring channel and a material cake.
(4) Cutting off excess materials: and the lower pressure head and the ejector rod simultaneously move upwards to eject the beryllium bronze explosion-proof hammer blank with the pouring channel and the material cake, the beryllium bronze explosion-proof hammer blank is transferred to a punching work part, the pouring channel and the material cake are separated from the beryllium bronze explosion-proof hammer blank by using a punching machine, and the beryllium bronze explosion-proof hammer blank is subjected to heat treatment.
(5) Finishing and heat treatment: and carrying out heat treatment on the aluminum bronze explosion-proof hammer blank, and polishing to obtain the beryllium bronze explosion-proof hammer.
Example 4
A method for manufacturing a beryllium bronze explosion-proof hammer by using the metal mold comprises the following steps:
(1) smelting the beryllium bronze alloy to obtain beryllium bronze alloy liquid; the beryllium bronze alloy comprises the following components in percentage by mass: be 2.20% and the balance Cu, Ni-free; the melting temperature is 1400 ℃.
(2) Closing the mold and locking the mold: and (3) pouring the beryllium bronze alloy liquid into the material storage cavity of the lower half mold by gravity for 2-5 seconds, closing the upper half mold and the lower half mold, pressurizing and locking, wherein the pouring temperature is 1200 ℃. The applied pressure (N) is more than or equal to the horizontal projection area (mm) of the whole cavity2)×170(MPa)。
(3) Pressurizing and solidifying: and pushing the beryllium bronze alloy liquid in the storage cavity by using the lower pressure head within 1-3 seconds after the mold locking pressure is added to a set value, enabling the alloy liquid to enter an explosion-proof hammer cavity through a flow channel, increasing the pressure to enable the internal pressure of the beryllium bronze alloy liquid to reach 170MPa, keeping the pressure for 1-10 seconds, applying downward pressure to the beryllium bronze alloy liquid by using the upper pressure head to enable the part below the upper pressure head to form high pressure of 170MPa for feeding, keeping the pressure when the bottom surface of the upper pressure head is flush with the top surface of the explosion-proof hammer cavity, and standing until the beryllium bronze alloy liquid is completely solidified to obtain a beryllium bronze explosion-proof hammer blank with a pouring channel and a material cake.
(4) Cutting off excess materials: and the lower pressure head and the ejector rod simultaneously move upwards to eject the beryllium bronze explosion-proof hammer blank with the pouring channel and the material cake, the beryllium bronze explosion-proof hammer blank is transferred to a punching work part, the pouring channel and the material cake are separated from the beryllium bronze explosion-proof hammer blank by using a punching machine, and the beryllium bronze explosion-proof hammer blank is subjected to heat treatment.
(5) Finishing and heat treatment: and carrying out heat treatment on the aluminum bronze explosion-proof hammer blank, and polishing to obtain the beryllium bronze explosion-proof hammer.
Examples of effects
The beryllium bronze explosion-proof hammer heads prepared in the examples 2 to 4 were subjected to performance tests, and the results are shown in the following table 1.
Table 1 results of performance testing
In example 2, under the holding pressure of 100MPa and the feeding pressure of 100MPa, the crystal grains of the formed part are refined, and the density is improved, so that the hardness and the tensile strength are correspondingly increased; because no casting riser is arranged and the runner has compact structure, the processing excess material is less, the process yield is high and can reach more than 80 percent.
In example 3, the holding pressure was 160MPa, the feeding pressure was 200MPa, the pressure was further increased, and the grain size and the structure of the molded article were refined and dense, thereby increasing the hardness and the tensile strength.
In example 4, the content of Be was 2.20%, and the higher content of Be increased the hardness of the material, and at the same time, the grain size of the material was refined at the higher holding pressure of 170MPa and the feeding pressure of 170MPa, and the hardness, tensile strength and density of the product were improved.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents or improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.