CN113894271A - Method for refining crystal grains and increasing metal density by using suspension oscillation shear and breaking force - Google Patents

Method for refining crystal grains and increasing metal density by using suspension oscillation shear and breaking force Download PDF

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Publication number
CN113894271A
CN113894271A CN202110980469.6A CN202110980469A CN113894271A CN 113894271 A CN113894271 A CN 113894271A CN 202110980469 A CN202110980469 A CN 202110980469A CN 113894271 A CN113894271 A CN 113894271A
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Prior art keywords
oscillation
suspension
casting
pouring
steps
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CN202110980469.6A
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Chinese (zh)
Inventor
赵清祯
崔芮元
刘长利
翟国山
李林
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Hebei Ruiou Intelligent Equipment Co ltd
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Hebei Ruiou Intelligent Equipment Co ltd
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Priority to CN202110980469.6A priority Critical patent/CN113894271A/en
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/08Shaking, vibrating, or turning of moulds

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)

Abstract

The invention discloses a method for refining crystal grains and increasing metal density by using suspension oscillation shear and breaking force, which is characterized by comprising the following steps of: it comprises the following steps: (1) preparing a vibrated body; (2) selecting suitable combination parameters for standby; (3) selecting an oscillating device; (4) and placing the produced vibrated body on a suspension oscillation device and fixing. (5) Starting an oscillation source; (6) the pouring can be started after the oscillation system is kept running stably for two minutes; (7) and (3) conveying the qualified molten metal to a vibration system to start pouring, keeping the pouring time for 6-11 minutes from the beginning, stopping the system from running, and taking the casting out of the box within the time required by cooling in the box. The invention has the following advantages: the invention can improve the grain size of the casting body by 1-2 levels; the invention can improve the density of the casting body by 3-7%.

Description

Method for refining crystal grains and increasing metal density by using suspension oscillation shear and breaking force
Technical Field
The invention relates to the technical field of metal materials, in particular to a method for refining crystal grains and increasing metal density by using suspension oscillation shear and breaking force.
Background
For multi-grain metals, there are several methods of refining the grains:
casting with a metal mold: the method comprises the following steps of metal mold casting in several forms, such as a metal model, iron mold sand-lined sand, iron sand and the like; the method forms a larger supercooling degree on the surface of a casting when encountering a supercooling metal mold, so that the metal is rapidly cooled to obtain finer grains, and the grain size of the metal on the surface of the casting is improved, thereby achieving the purpose of refining the grains; the method has the disadvantages that the method can only refine crystal grains within 0-10mm of the surface of the casting, the density of internal and external tissues of the casting is not uniform, and the density of the casting, particularly the overall density of the casting is not greatly improved; the method is only suitable for grain refinement of the surface, local and thin-wall parts of the casting, and the required auxiliary equipment is large in quantity and low in efficiency.
The method for alloying and refining the grains comprises the following steps: the method is that a plurality of precious composite metals are added into molten metal, so as to change the metal characteristics and increase the nucleation number and the tissue form, thereby achieving the purpose of refining crystal grains and improving the mechanical properties of the metal; the method only has the effect of refining grains, but has little effect of improving the density of the casting and has higher cost.
Electromagnetic casting and grain refinement: the method is characterized in that an electromagnetic device with high magnetic flux is applied outside a traditional casting mold, so that crystal grains can be distributed and refined according to a designed direction when a casting is solidified, and the method is only applied to special castings and on local surfaces and small pieces; the defects that the auxiliary equipment is needed, the cost is high, and the high-magnetic-flux magnetic field has poor safety to the environment and human bodies and has little effect of improving the integral density of the casting.
Grain refinement by heat treatment: the method heats the casting blank again or for multiple times, so that the grain recombination of the casting achieves the grain refinement effect of the casting, but the method has no effect on the density improvement of the casting, prolongs the longer production period and increases the cost.
Disclosure of Invention
The invention aims to overcome the technical defects and provides a method for refining crystal grains and increasing metal density by using suspension oscillating shear and breaking force.
A method for refining crystal grains and increasing metal density by using suspension oscillation shear and breaking force is characterized in that: it comprises the following steps:
(1) preparing a vibrated body;
(2) selecting suitable combination parameters for standby;
(3) selecting an oscillating device;
(4) and placing the produced vibrated body on a suspension vibration device and fixing.
(5) Starting an oscillation source;
(6) the pouring can be started after the oscillation system is kept running stably for two minutes;
(7) and (3) conveying the qualified molten metal to a vibration system to start pouring, keeping the pouring time for 6-11 minutes from the beginning, stopping the system from running, and taking the casting out of the box within the time required by cooling in the box.
As an improvement, the suspension oscillation system consists of two parts, namely a suspension oscillation device and an oscillated body.
As an improvement, the oscillation device consists of an oscillation source, a steel structure body, an elastic system and an electric control cabinet; the oscillation device comprises two forms: one is a suspension type suspension oscillation device, which depends on the device to be suspended completely by the oscillation body, so that the oscillation body is suspended in the air, and the oscillation source transmits alternating force in the horizontal circular axis direction, and finally the alternating force is converted into alternating creep shearing breaking force to act on a casting which is being solidified; the other is a vertical suspension oscillation device, which depends on a device to vertically support an oscillated body, when an oscillation source outputs a vertical upward force, the oscillation source is upwards bounced through an elastic body, is instantly suspended (suspended), and then is downwards moved by gravity, so that the oscillation suspension force is transmitted to the oscillated body according to a certain frequency by alternating up and down reciprocation.
As an improvement, the vibrated body consists of a rigid sandbox, high-temperature resistant molding sand (the compactness is more than 85), high-temperature refractory coating and a casting cavity or solid with a pouring system (a lost foam casting model is a foam solid).
As an improvement, the combination parameters include the following parameter contents: steel casting: the solidification range is wide, and the paste is solidified; the thickness of the casting is more than 50mm, the weight is about 200kg, and no disconnected hot junction exists; top pouring; pouring temperature: 1460-1510 ℃; pouring speed: 5-7 kg/s; the pouring dynamic pressure head is larger than 800 mm; coating: if the lost foam casting method is used for producing the casting, the casting is selectedThe strength of the molding sand is more than 85, and if the coating is produced by a lost foam, the negative pressure is more than-0.065 MP; the oscillation mode is a vertical oscillation method (or a suspension horizontal circle center oscillation method); retention time: 6-11 minutes; the force applied to the vibrated body by the horizontal vibration is 12-30kg/m3The force applied to the vibrated body by vertical vibration is 62-120kg/m3(ii) a The amplitude is 0.5-1.5 mm; oscillation frequency 3000 + 4500 rpm.
The invention has the following advantages: the invention is mainly combined and filled in the pouring link in the casting method in the past, and is one of the main methods for improving the quality of the casting body; the method is suitable for lost foam casting, resin sand, sodium silicate sand, clay sand, green sand, dry molding sand, shell molding sand and the like, and can be finally converted into a casting method with alternating creep shearing breaking force in a cavity as long as the continuous rigid force transmission condition can be met. Only the corresponding suspension oscillation devices are needed to be configured; the method is suitable for automatic production lines and dispersion production lines; the method is suitable for castings made of nonferrous metal cast iron cast steel metal materials (the structural wall thickness is more than 30 mm); the effect on thick-wall metal castings which are wide in solidification range and pasty to solidify is more obvious; the principle of refinement and densification is first thoroughly clarified. Then selecting a correct suspension oscillation device; selecting correct and reasonable combination parameters; the invention can realize riser-free casting of thick and large section castings (50-200 mm); aiming at the disconnected hot spot steel casting, the multi-point hot spot steel casting with the thickness (less than 25 mm) of a hot junction main structure of 3:1 realizes riser-free pouring without shrinkage porosity, improves the process yield by 40 percent, and plays a role in energy conservation and high efficiency; the invention can improve the grain size of the casting body by 1-2 levels; the invention can improve the density of the casting body by 3-7%.
Detailed Description
The present invention will be further described with reference to specific examples, which are intended to be illustrative, not limiting and are not intended to limit the scope of the invention.
The invention uses a suspension oscillation shearing and breaking force to shear or break large dendritic crystals in the metal liquid which is about to be completely solidified; thereby the metal of the cast metal refines crystal grains, and simultaneously the feeding channel of the molten metal is opened, thereby further increasing the metal density.
The principle of grain refinement: each metal is subjected to high-temperature liquid state, low-temperature liquid state and semi-solidification mixed liquid state from liquid metal to final solidification, and finally solidified and cooled to the final normal-temperature solid metal; the invention uses physical method to give alternating oscillating force to the system; finally, the molten metal is conducted into a molten pool in a semi-solidification state of liquid-solid mixing; the word is composed of N micro-melting pool units; each micro-unit molten pool is composed of rapidly growing dendrites, more viscous liquid metal and other compounds with high and low melting points; the viscous metal liquid can receive external force and be converted into alternating creep shearing force and alternating breaking force; acting on the dendritic crystal growing in an express way, shearing or breaking the dendritic crystal (depending on the direction of force application), so that the size of the dendritic crystal is reduced, and finally the key point of refining the crystal grain is that the alternating creep shearing and breaking force can be generated under the action of external force only when the liquid metal has certain viscosity; the key point is that the liquid metal can generate alternating creep shearing and breaking force under the action of external force only under a certain viscosity.
The principle of metal liquid feeding and density increasing is as follows: micro cavity space is formed between each molten pool unit and the adjacent unit due to metal solidification shrinkage, namely micro loose; the dendritic crystal grows and solidifies in a free state without any measures, so that countless dendritic crystals grow crosswise; forming macroscopic holes; if the state can not be changed in time, the metal liquid is blocked to supplement the channel of the space, and finally, macroscopic shrinkage porosity is formed; the net result of these two conditions is a substantial reduction in the density of the metal casting; the invention utilizes a suspension oscillation external force for a system to be transmitted to a viscous molten liquid to be converted into a plurality of alternating creep deformation and shearing breaking force, and the criss-cross thick dendritic crystals growing in a free state are sheared and broken; the feeding channel is opened, so that the flowable metal liquid can be timely fed into the two cavities, namely timely feeding, and the metal casting without shrinkage porosity is obtained.
Example 1
A method for producing high-carbon alloy wear-resistant steel castings by using suspension oscillation shear and breaking force to refine crystal grains and increase metal density comprises the following parameter selection:
(1) the main chemical component C is 1.17%;
(2) the weight of the casting is 450 kg;
(3) the thickness of the casting is 140mm, the height is 850mm, and the structure is simple;
(4) the residual thickness after use and abrasion is 50mm, namely the layer-by-layer abrasion thickness is 90 mm;
(5) selecting a lost foam casting process with negative pressure of-0.06 Mp;
(6) selecting a vertical suspension oscillation device;
(7) the casting temperature is 1430 ℃;
(8) the pouring speed is 6-7 kg/s;
(9) the minimum dynamic pressure head is 850 mm;
(10) the holding time is nine minutes;
(11) cooling in a box for five hours after pouring;
the product has the following effects:
the upper, middle and lower parts, the surface and the internal structure of the fracture of the casting are uniform, fine and compact; the grain size is improved by one to two grain sizes compared with the traditional method; no shrinkage porosity, compact tissue, and 5-6% higher density than the conventional method.
Example 2
A method for refining crystal grains and increasing metal density by using suspension oscillating shear and breaking force is used for producing a structural member of medium carbon alloy steel, and casting parameter selection is as follows:
(1) the main chemical components C: 0.27 percent;
(2) a casting structure; an alloy cast steel bracket; is characterized by five disconnected hot junctions; the hot junction diameter is 55mm, and the thickness of the upper disc and the lower disc is 18 mm; the diameter is 410 mm;
(3) top pouring at the pouring position;
(4) a lost foam casting method;
(5) producing by using a vertical suspension oscillation device;
(6) pouring without a cap opening;
(7) the pouring temperature is 1480 ℃;
(8) the pouring speed is 9 kg/s;
(9) the negative pressure is-0.075 Mp;
(10) the holding time is five minutes;
the product has the following effects:
the conventional casting hot spot without a riser has serious shrinkage porosity, and a qualified product can be produced only by adding 40% of risers; the piece is produced by a suspension oscillation method without a riser, shrinkage porosity does not exist at a hot spot, and the process yield is improved by 40%; is a good method in the aspects of saving energy and improving production efficiency.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the present specification, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (5)

1. A method for refining crystal grains and increasing metal density by using suspension oscillation shear and breaking force is characterized in that: it comprises the following steps:
(1) preparing a vibrated body;
(2) selecting suitable combination parameters for standby;
(3) selecting an oscillating device;
(4) and placing the produced vibrated body on a suspension vibration device and fixing.
(5) Starting an oscillation source;
(6) the pouring can be started after the oscillation system is kept running stably for two minutes;
(7) and (3) conveying the qualified molten metal to a suspension oscillation system to start pouring, keeping the pouring time for 6-11 minutes from the beginning, stopping the system from operating, and taking the casting out of the box within the time required by cooling in the box.
2. The method of claim 1, wherein the method comprises the steps of refining grains by using a suspension oscillating shear and a breaking force to increase metal density, wherein the method comprises the following steps: the suspension oscillation system consists of two parts, namely a suspension oscillation device and an oscillated body.
3. The method of claim 2, wherein the method comprises the steps of refining grains by using a suspension oscillating shear and a breaking force to increase the metal density, wherein the method comprises the following steps: the vibration device consists of a vibration source, a steel structure body, an elastic system and an electric control cabinet; the oscillation device comprises two forms: one is a suspension type suspension oscillation device, which depends on the device to be suspended completely by the oscillation body, so that the oscillation body is suspended in the air, and the oscillation source transmits alternating force in the horizontal circular axis direction, and finally the alternating force is converted into alternating creep shearing breaking force to act on a casting which is being solidified; the other is a vertical suspension oscillation device, which depends on a device to vertically support an oscillated body, when an oscillation source outputs a vertical upward force, the oscillation source is upwards bounced through an elastic body, is instantly suspended (suspended), and then is downwards moved by gravity, so that the oscillation suspension force is transmitted to the oscillated body according to a certain frequency by alternating up and down reciprocation.
4. The method of claim 2, wherein the method comprises the steps of refining grains by using a suspension oscillating shear and a breaking force to increase the metal density, wherein the method comprises the following steps: the vibrated body consists of a rigid sandbox, high-temperature resistant molding sand (the compactness is more than 85), high-temperature refractory coating and a casting cavity or entity with a pouring system (a lost foam casting model is a foam entity).
5. The method of claim 1, wherein the method comprises the steps of refining grains by using a suspension oscillating shear and a breaking force to increase metal density, wherein the method comprises the following steps: the combination parameters include the following parameter contents: steel casting: the solidification range is wide, and the paste is solidified; the thickness of the casting is more than 50mm, the weight is about 200kg, and no disconnected hot junction exists; top pouring; pouring temperature: 1460-1510 ℃; pouring speed: 5-7 kg/s; the pouring dynamic pressure head is larger than 800 mm; coating: if the casting is produced by the lost foam casting method, the coating with high-temperature strength is selected, the strength of the molding sand is more than 85, and if the casting is produced by the lost foam, the negative pressure is more than-0.065 MP; the oscillation mode is a vertical oscillation method (or a suspension horizontal circle center oscillation method); retention time: 6-11 minutes; the force applied to the vibrated body by the horizontal vibration is 12-30kg/m3The force applied to the vibrated body by vertical vibration is 62-120kg/m3(ii) a The amplitude is 0.5-1.5 mm; oscillationFrequency 3000 plus 4500 rpm.
CN202110980469.6A 2021-08-25 2021-08-25 Method for refining crystal grains and increasing metal density by using suspension oscillation shear and breaking force Pending CN113894271A (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5533879A (en) * 1978-08-31 1980-03-10 Takaoka Kogyo Kk Precision casting method utilizing vibration
JPS59166345A (en) * 1983-03-11 1984-09-19 Toyota Motor Corp Pack casting method
CN101181746A (en) * 2007-11-23 2008-05-21 华中科技大学 Vibration Solidification Method of Lost Foam Casting
JP2010069514A (en) * 2008-09-19 2010-04-02 National Institute Of Advanced Industrial Science & Technology Casting method with vibration solidification, casting mold for the same method, and casting apparatus with vibration solidification
CN101898228A (en) * 2010-07-31 2010-12-01 刘玉满 Method for casting sound casting by using lost foam coated with high-performance coating in vibration way
CN102744367A (en) * 2012-07-17 2012-10-24 武汉工程大学 Lost foam-shell mold casting vibration and solidification method based on foam mold

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5533879A (en) * 1978-08-31 1980-03-10 Takaoka Kogyo Kk Precision casting method utilizing vibration
JPS59166345A (en) * 1983-03-11 1984-09-19 Toyota Motor Corp Pack casting method
CN101181746A (en) * 2007-11-23 2008-05-21 华中科技大学 Vibration Solidification Method of Lost Foam Casting
JP2010069514A (en) * 2008-09-19 2010-04-02 National Institute Of Advanced Industrial Science & Technology Casting method with vibration solidification, casting mold for the same method, and casting apparatus with vibration solidification
CN101898228A (en) * 2010-07-31 2010-12-01 刘玉满 Method for casting sound casting by using lost foam coated with high-performance coating in vibration way
CN102744367A (en) * 2012-07-17 2012-10-24 武汉工程大学 Lost foam-shell mold casting vibration and solidification method based on foam mold

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
知水等: "《机械振动对钢锭结晶过程的影响》", 31 August 1959, 冶金工业出版社 *
肖海波等: "振动浇注在精密铸造中的应用", 《特种铸造及有色合金》 *

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Application publication date: 20220107