阅读说明：本技术 一种锌合金压铸件及其熔炼方法 (Zinc alloy die casting and smelting method thereof ) 是由 吴健 于云峰 梁寅 李英 吴泽宏 孙茂银 于 2020-06-15 设计创作，主要内容包括：本发明公开了一种锌合金压铸件及其熔炼方法,锌合金原料为铝3.5份-4.5份、镁0.03份-0.05份、铜0.1份-0.2份、锌95.3份-96.4份、AlTi5B 0.32份-0.4份；致密度99.5%-99.8%,抗拉强度330MPa-350MPa,延伸率3.2%-3.5%,硬度105-130HB,冲击韧性39Ak(J)-43Ak(J),金属液经熔炼中三次电磁搅拌复合液压振动处理获得,浇铸时以按目标产品设计平均壁厚Dmm计充型时间10D毫秒-11D毫秒,持压时间D/2秒-D/1.8秒,脱模时间D<Sup>2</Sup>秒-2D<Sup>2</Sup>/3秒。本发明适用于复杂锌基合金、除气高效、力学性能好、致密度高、尺寸精密度好。(The invention discloses a zinc alloy die casting and a smelting method thereof, wherein zinc alloy raw materials comprise 3.5-4.5 parts of aluminum, 0.03-0.05 part of magnesium, 0.1-0.2 part of copper, 95.3-96.4 parts of zinc and 0.32-0.4 part of AlTi5B 0.32; 99.5 to 99.8 percent of compactness, 330 to 350MPa of tensile strength, 3.2 to 3.5 percent of elongation, 105-hardness 130HB, 39Ak (J) -43Ak (J) of impact toughness, wherein the molten metal is obtained by three times of electromagnetic stirring composite hydraulic vibration treatment in smelting, the filling time is 10D milliseconds to 11D milliseconds, the holding pressure time is D/2 seconds to D/1.8 seconds, and the demolding time is D when casting is carried out according to the designed average wall thickness Dmm of a target product 2 second-2D 2 And/3 seconds. The invention is suitable for complex zinc-based alloy, and has the advantages of high degassing efficiency, good mechanical property, high density and good size precision.)

1. A smelting method of a zinc alloy die casting is characterized by comprising the following steps:

preparation before production

Preparing alloy raw materials: preparing 3.5-4.5 parts of metal raw material aluminum, 0.03-0.05 part of magnesium, 0.1-0.2 part of copper, 95.3-96.4 parts of zinc and 0.32-0.4 part of aluminum-titanium-boron intermediate alloy AlTi5B 0.32 according to parts by weight;

preparing equipment: preparing a pot-shaped graphite crucible with a protruding structure at the bottom, a side heating device matched with the pot-shaped graphite crucible, sufficient nickel-based soft magnetic alloy scraps with the grain diameter of 3-5 mm, an electromagnetic stirring generating device arranged below the bottom of the pot-shaped graphite crucible, a hydraulic up-and-down reciprocating vibration device fixedly locked at the bottom of the pot-shaped graphite crucible, and a die casting device with the liquid injection speed of 40-50 m/s;

preparing a mould: preparing an austenitic stainless steel die-casting die preheated to 165-180 ℃;

secondly, after the raw materials and the nickel-based soft magnetic alloy scraps prepared in the step one are subjected to oil removal treatment by an ultrasonic oil remover, the raw materials and the nickel-based soft magnetic alloy scraps are respectively cleaned by ethanol and then dried for later use, and the raw materials for later use, the aluminum-titanium-boron intermediate alloy AlTi5B for later use and the clean nickel-based soft magnetic alloy scraps are respectively obtained;

thirdly, putting the clean nickel-based soft magnetic alloy scraps obtained in the second step into the pot-shaped graphite crucible prepared in the first step to enable the clean nickel-based soft magnetic alloy scraps to sink to the bottom of the pot-shaped graphite crucible, and putting the raw materials to be used into the pot-shaped graphite crucible to enable the raw materials to cover the nickel-based soft magnetic alloy scraps;

starting the heating device until the temperature of the graphite crucible rises to 415-420 ℃, and starting heat preservation; starting to melt the raw materials to be used, starting an electromagnetic stirring generating device under the condition of keeping heating when the raw materials to be used are melted to 1/4-1/3 volume, controlling the stirring strength to keep the liquid part flowing visible with naked eyes but not bubbling or rolling, and stopping stirring once after lasting for 3-4 min; continuously heating until the volume of the raw material is 1/2-3/5, starting the electromagnetic stirring generating device again under the condition of keeping heating, controlling the stirring strength to be controlled to enable the liquid part to have visual flow without bubbling or rolling, continuing for 6-8 min, and stopping secondary stirring; continuously maintaining heating until the raw materials are completely melted, then putting the obtained Al-Ti-B intermediate alloy AlTi5B to be used in the step II into molten metal, starting an electromagnetic stirring generating device under the condition of maintaining heating, wherein the stirring strength is that a wave pattern appears at the joint of the edge of the liquid level and a graphite crucible and the height of the wave pattern is controlled to be 3mm-5mm, continuing for 12min-15min, then starting a hydraulic up-and-down reciprocating vibration device while maintaining electromagnetic stirring and heating, carrying out vibration treatment at the frequency of 1 time/second-1.2 times/second, each time being a complete up-and-down reciprocating period, the vibration height range being 0.8cm-2cm, continuously vibrating, carrying out electromagnetic stirring and heating composite treatment for 5min-6min, slagging, and then obtaining casting molten metal;

⑤ adopting the die casting device prepared in the step ①, injecting the casting metal liquid obtained in the step ④ into the austenitic stainless steel die casting die prepared in the step ① with the filling time of 10D milliseconds to 11D milliseconds according to the design average wall thickness Dmm of the target product, then holding and pressing for D/2 seconds to D/1.8 seconds, and after the holding and pressing are completed, standing for D²second-2D²And demolding after the time of/3 seconds, and cooling in air to room temperature to finish the one-step molding of the complex zinc alloy precision casting.

2. A zinc alloy die casting produced by the method for melting a zinc alloy die casting according to claim 1, wherein: the zinc alloy die casting comprises 3.5-4.5 parts of aluminum, 0.03-0.05 part of magnesium, 0.1-0.2 part of copper, 95.3-96.4 parts of zinc and 0.32-0.4 part of Al-Ti-B intermediate alloy AlTi5B 0.32; the qualified standard of the zinc alloy die casting is as follows: 99.5 to 99.8 percent of compactness, 330 to 350MPa of tensile strength, 3.2 to 3.5 percent of elongation, 105 to 130HB of hardness and 39Ak (J) -43Ak (J) of impact toughness.

Technical Field

The invention relates to the technical field of zinc alloy smelting, in particular to a zinc alloy die casting and a smelting method thereof.

Background

With the development of times, the casting quality requirements of zinc alloy precision casting parts are higher and higher, and the defects of flash, burr and crack can not exist on the surfaces of the parts and air holes can not exist in the parts if the requirements are met; on the other hand, the requirement on the size precision also puts forward higher requirements on the mechanical property of the casting, but the higher requirements on the mechanical property mean that the alloy elements are complicated, and the great increase of smelting difficulty is brought. Taking zinc-based alloys as an example, the process of the multi-component alloy is much more complicated than that of the ternary alloy; the ternary alloy can be produced by primary smelting and secondary smelting process. Because the cost of secondary smelting is higher than that of primary smelting, many enterprises are willing to adopt the primary smelting process to produce ternary alloy. The multi-element alloy is formed by adding one or more alloy components on the basis of the ternary alloy, the smelting technology is naturally complex, one or more elements are added randomly in the general smelting technical level, and the elements are difficult to add in actually, so the multi-element zinc alloy in the prior art is usually prepared by smelting for many times through a complex process and precise control.

Disclosure of Invention

The invention aims to provide a zinc alloy die casting which is suitable for complex zinc-based alloy, has high degassing efficiency, good mechanical property, high density and good size precision and a smelting method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme: a smelting method of a zinc alloy die casting comprises the following steps:

preparation before production

Preparing alloy raw materials: preparing 3.5-4.5 parts of metal raw material aluminum, 0.03-0.05 part of magnesium, 0.1-0.2 part of copper, 95.3-96.4 parts of zinc and 0.32-0.4 part of aluminum-titanium-boron intermediate alloy AlTi5B 0.32 according to parts by weight;

preparing equipment: preparing a pot-shaped graphite crucible with a protruding structure at the bottom, a side heating device matched with the pot-shaped graphite crucible, sufficient nickel-based soft magnetic alloy scraps with the grain diameter of 3-5 mm, an electromagnetic stirring generating device arranged below the bottom of the pot-shaped graphite crucible, a hydraulic up-and-down reciprocating vibration device fixedly locked at the bottom of the pot-shaped graphite crucible, and a die casting device with the liquid injection speed of 40-50 m/s;

preparing a mould: preparing an austenitic stainless steel die-casting die preheated to 165-180 ℃;

secondly, after the raw materials and the nickel-based soft magnetic alloy scraps prepared in the step one are subjected to oil removal treatment by an ultrasonic oil remover, the raw materials and the nickel-based soft magnetic alloy scraps are respectively cleaned by ethanol and then dried for later use, and the raw materials for later use, the aluminum-titanium-boron intermediate alloy AlTi5B for later use and the clean nickel-based soft magnetic alloy scraps are respectively obtained;

thirdly, putting the clean nickel-based soft magnetic alloy scraps obtained in the second step into the pot-shaped graphite crucible prepared in the first step to enable the clean nickel-based soft magnetic alloy scraps to sink to the bottom of the pot-shaped graphite crucible, and putting the raw materials to be used into the pot-shaped graphite crucible to enable the raw materials to cover the nickel-based soft magnetic alloy scraps;

starting the heating device until the temperature of the graphite crucible rises to 415-420 ℃, and starting heat preservation; starting to melt the raw materials to be used, starting an electromagnetic stirring generating device under the condition of keeping heating when the raw materials to be used are melted to 1/4-1/3 volume, controlling the stirring strength to keep the liquid part flowing visible with naked eyes but not bubbling or rolling, and stopping stirring once after lasting for 3-4 min; continuously heating until the volume of the raw material is 1/2-3/5, starting the electromagnetic stirring generating device again under the condition of keeping heating, controlling the stirring strength to be controlled to enable the liquid part to have visual flow without bubbling or rolling, continuing for 6-8 min, and stopping secondary stirring; continuously maintaining heating until the raw materials are completely melted, then putting the obtained Al-Ti-B intermediate alloy AlTi5B to be used in the step II into molten metal, starting an electromagnetic stirring generating device under the condition of maintaining heating, wherein the stirring strength is that a wave pattern appears at the joint of the edge of the liquid level and a graphite crucible and the height of the wave pattern is controlled to be 3mm-5mm, continuing for 12min-15min, then starting a hydraulic up-and-down reciprocating vibration device while maintaining electromagnetic stirring and heating, carrying out vibration treatment at the frequency of 1 time/second-1.2 times/second, each time being a complete up-and-down reciprocating period, the vibration height range being 0.8cm-2cm, continuously vibrating, carrying out electromagnetic stirring and heating composite treatment for 5min-6min, slagging, and then obtaining casting molten metal;

⑤ adopting the die casting device prepared in the step ①, injecting the casting metal liquid obtained in the step ④ into the austenitic stainless steel die casting die prepared in the step ① with the filling time of 10D milliseconds to 11D milliseconds according to the design average wall thickness Dmm of the target product, then holding and pressing for D/2 seconds to D/1.8 seconds, and after the holding and pressing are completed, standing for D²second-2D²And demolding after the time of/3 seconds, and cooling in air to room temperature to finish the one-step molding of the complex zinc alloy precision casting.

The zinc alloy die casting manufactured by the method comprises the following raw materials of 3.5-4.5 parts of aluminum, 0.03-0.05 part of magnesium, 0.1-0.2 part of copper, 95.3-96.4 parts of zinc and 0.32-0.4 part of Al-Ti-B intermediate alloy AlTi5B 0.32; the qualified standard of the zinc alloy die casting is as follows: 99.5 to 99.8 percent of density, 330 to 350MPa of tensile strength, 3.2 to 3.5 percent of elongation, 105 to 130HB of hardness and 39Ak (J) -43Ak (J) of impact toughness

Compared with the prior art, the invention has the following advantages: (1) when the method is adopted to smelt zinc alloy, particularly multi-element complex zinc alloy, no slag removing agent, refining agent or degassing agent is needed to be added, so that the purity of the alloy can be obviously improved, and meanwhile, the nickel-based soft magnetic alloy scraps selected by the method are in a zinc matrixThe medium solid solubility is lower than that of iron, the melting point is far higher than that of zinc alloy, and the density is obviously higher than that of zinc alloy (the density is 8.8 g/cm)³-9.0g/cm³Is obviously larger than 6.6g/cm of zinc alloy³-6.8g/cm³) Therefore, the zinc alloy can be basically ignored as an impurity of a stirring medium of the nickel-based soft magnetic alloy to be embedded or dissolved in the zinc alloy in a solid solution mode, and meanwhile, the direct and high-strength stirring effect can be achieved, the zinc alloy with better uniformity and finer original grain size can be obtained, and the zinc alloy can be suitable for processing and manufacturing of civil aviation precision zinc alloy. (2) The invention designs and practically gradually perfects a three-in-one smelting device by adopting various advanced process depths, complexity and organic kneading which are not adopted by the existing zinc alloy and combining the flow characteristic and the degassing rule of a zinc alloy molten pool, and has the most prominent contribution that part of complex zinc alloy can be smelted and formed at one time, and the structure is uniform and the degassing is thorough. (3) The invention is a result obtained by deep research specially aiming at the smelting characteristics of the zinc alloy, is suitable for smelting most of high-end zinc alloy, and has strong professional and good quality controllability. (4) The tissue uniformity of the invention is ensured by a special crucible integral structure, a crucible bottom structure and a magnetic induction stirring medium triple mechanism, and specifically comprises the following steps: the integral structure of the crucible breaks away from the conventional mechanical stirring mechanism which enables the liquid flow main body to move only along the circumferential direction, the lifting force which is upward at the bottom and the extrusion force which is concentrated towards the center at the top are obtained, the magnetic induction stirring medium is quickly disturbed at the bottom by utilizing the external magnetic induction device to form a liquid flow vortex which is roughly orderly and locally differentiated at the bottom, the convex structure at the bottom of the crucible causes turbulent flow by utilizing the centrifugal force generated by the liquid flow in the rotation, and the three are combined to realize the all-dimensional uniform stirring action. (5) The degassing effect of the invention is realized by combining the full-three-dimensional homogenizing stirring action with the lifting of the graphite crucible by the hydraulic vibration systemThe specific principle of the combined guarantee of the up-and-down reciprocating motion is similar to the common ultrasonic degassing/defoaming in the technical field of electroplating, and the gas with the density obviously lower than that of the alloy liquid can be more quickly and thoroughly removed by compounding the internal high-speed motion with the external forced vibration. Therefore, the invention has the characteristics of high degassing efficiency, good mechanical property, high density and good size precision, and is suitable for complex zinc-based alloy.

Drawings

FIG. 1 is a picture of the crystal phases of an unmodified zinc alloy produced by the method of the invention;

FIG. 2 is a picture of the crystal phases of an unmodified zinc alloy manufactured based on a conventional melting method by using the same formulation as the present invention;

FIG. 3 is a picture of the crystal phases of an AlTi5B modified zinc alloy produced by the method of the present invention;

FIG. 4 is a picture of the crystal phases of AlTi5B modified zinc alloy manufactured based on the conventional melting method by using the same formula as the present invention.

Detailed Description