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Spring Design Attention And Roll Forming Method

The coiling characteristics and methods of springs are divided into cold coiling method and hot coiling method. Cold winding method: When the diameter of the spring wire is less than 8mm, the cold winding method is adopted. High-quality carbon spring steel wire is usually first cold drawn and then heat treated. After winding, it is generally not quenched, but only tempered at low temperature to eliminate the internal stress during winding. Hot-rolling method: Springs with larger diameter (>8mm) spring wire should use hot-rolling method. Hot rolled springs must be quenched and tempered at medium temperature.

The Design Process Of Various Springs

·Installation space: When designing a compression spring, it is necessary to have a clear understanding of the space required for the installation of the spring, in order to effectively grasp the basic manufacturing conditions of the compression spring, including the outer diameter, inner diameter and free length.

·Dynamic stroke load: In the design of the compression spring, the position to be activated and the required bearing capacity must be clearly understood. Determine the location of the desired elasticity, then you can determine the material, wire diameter, number of turns.

·Environmental factors: When the spring works in different environments, it will be affected by environmental factors and affect the service life of the spring. Therefore, designers must consider changes in ambient temperature and humidity. Temperature has a great influence on the service life of the spring, and humidity is easy to oxidize the spring without surface treatment. Therefore, environmental factors can determine whether the spring needs surface treatment and material selection.

·Spacing at both ends: The two ends of the tension springwill affect the shape of the hook and the free length of the tension spring. Space can determine the size and outer diameter of the contacts.

·Pre-tightening force: The pre-tightening force determines the material of the spring and the diameter of the steel wire, and the size of the fastener can adjust the pre-tightening length.

·The outer diameter of the main shaft: the inner diameter of the torsion spring can be determined according to the size of the main shaft, but the change of the spring body after torsion should be considered, and an appropriate allowance can be reserved.

·The inner diameter of the installation space: When the torsion springinstallation adopts the “in” type, the “in” type space should be considered. The space determines the outer diameter, free length and number of turns of the spring body.

·Torsion fulcrum: The torsion spring must have a fulcrum when it works. This fulcrum can determine the length and form of the torsion bar.

·The starting and ending points of the action: the angle position between the torsion bar and the fulcrum when no work is done can clearly define the length and form of the torsion bar and the angle between the torsion bar and the fulcrum bar.

The Spring Winding Method

·The hot winding of the spring generally means that the spring wire diameter D must be greater than 8mm before the hot winding can be used. When the spring is rolled in a hot state, quenching and tempering must be carried out before rolling. Only then can a spring produced by hot rolling be considered a better spring.

·The cold winding method generally refers to the cold winding method only when the diameter D of the spring steel wire is less than or equal to 8mm. In the cold state, the commonly used coil spring material is cold drawn and preheated high-quality carbon steel springwire. After coiling, quenching is generally not performed. Only low temperature tempering can eliminate the internal stress during the coiling process.

The Winding Process Of The Spring

·If the outer diameter of the spring is close to the free length, the specification will also cause problems. When the outer diameter approaches the free length, the spring tends to lose its directionality in the fixture, causing parts to jam and assembly equipment to shut down.

·There are so many types in shape, size and material that it is difficult to choose the right disposal tissue from the box. The design of the spring can vary if it is not a single shaped product. In general, the allowable tolerance of the spring is slightly larger, so straightness, length, outer diameter, cleanliness, etc. should be considered more widely when feeding.

·How to submit the spring is the key. Generally, springs are supplied in bulk and can be bagged at will. Springs are best served in a pan if possible, or in any other way that they can be served individually. We’re seeing more of that in Europe.

·There are many media supply systems available for bulk springs. They take into account the design of the spring, the difficulty of separating the spring, and the feed rate that needs to be achieved. If a fully automatic system is required, or if a spring is too difficult to separate and feed, in-line winding of the spring is a good solution, and in many cases the best solution. In-line winding of the spring eliminates all winding problems. Springs can be wound and cut as required. Only supply one spring to the operator at a time or directly to the assembly point.

·In addition, in-line cnc machining can use resistance heating to process springs, and can also measure spring force, spring length and diameter. In this way, only qualified springs (including extension springs, special-shaped springs, torsion springs, etc.) that meet the specified tolerances can be supplied to the final assembly. Any springs that exceed the specified tolerances must be removed prior to assembly.

LinkSpring Design Attention And Roll Forming Method

REF: Carbon Steel Spring, Torsion Springs, Metal Spring Type

The Rubbing Shaft Is An Important Part For Many Large Machines

Today, with the rapid development of the machinery industry, the manufacturing level of various mechanical parts has been continuously improved, the physical properties have been significantly improved, and the machinery industry has also achieved rapid development. The rubbing shaft is used in many large machines and is an important transmission component. The development of today’s machinery and equipment has promoted the development of the rubbing shaft.

In the process of rolling flower shaft, some failures are unavoidable, but some problems can be avoided or rarely encountered. As a production worker, you must be familiar with the solutions to some common problems so as not to affect product quality during use. So let’s take a look at how to solve the problem of springback and bending of the rubbing shaft.

metal-spring.com springs Type include : Compression Spring,Extension Springs,Torsion Spring,Flat Spring,Special Shape Spring,Die Springs,Spring Machining.

First, the springback is controlled using a process control method. Typically, this process includes stamping, stretch bendingand hot bending. During the stamping process, the additional stress in the thickness direction changes the stress distribution in the bending deformation zone. The springback is controlled by applying tangential tensile deformation and reducing the bending moment at the bend of the twisted shaft.

The second method is overcompensation and the other is process control. Depending on the springback trend, make a compensation angle in the die consistent with the expected springback, or control the punch overshoot. This is the so-called compensation method. This is a widely used method of controlling the twisted backboard. However, when there are complex curved products and high precision requirements, the precision control of springback is limited because it is difficult to accurately estimate the springback.

LinkThe Rubbing Shaft Is An Important Part For Many Large Machines

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Five aspects of sheet metal sandblasting applications

Sheet metalsandblasting uses compressed air as the power to form a high-speed jet beam to spray the spray material on the surface of the workpiece to be treated at a high speed, so that the appearance or shape of the outer surface of the workpiece surface changes. The impact and laser cuttingaction make the surface of the workpiece obtain a certain degree of cleanliness and different roughness, so that the mechanical properties of the workpiece surface are improved, thus improving the fatigue resistance of the workpiece and increasing the adhesion between it and the coating, Extends the durability of the coating film, and also facilitates the leveling and decoration of the coating.

There are five main applications of sandblasting:

1. Improve the mechanical properties of the parts After sandblasting, Cnc turnning parts can produce uniform and fine concave and convex surfaces on the surface of the parts, so that the lubricating oil can be stored, thereby improving the lubricating conditions, reducing noise and improving the service life of the machine.

2. Sandblasting before workpiece coating and workpiece bonding can remove all dirt such as rust on the surface of the workpiece, and establish a very important basic pattern on the surface of the workpiece. The abrasives of the exhibition abrasive tools reach different degrees of roughness, which greatly improves the bonding force between the workpiece and the paint and plating. Or make the bonding parts more firm and better in quality.

3. Cleaning and polishing sandblasting of rough surface of castings and workpieces after heat treatment can clean all dirt on the surface of castings and forgings and workpieces after heat treatment, and polish the surface of workpieces to improve the smoothness of workpieces, so that the workpieces can reveal uniform and consistentmetal forging color. Make the workpiece appearance more beautiful and good-looking.

4. Lighting effect For some special-purpose workpieces, sandblasting can achieve different reflections or matts at will. Such as the polishing of stainless steel workpieces and plastics, the polishing of jade articles, the mattization of the surface of wooden furniture, the pattern of frosted glass surfaces, and the textured processing of cloth surfaces.

5. Burr cleaning and surface beautification of machined parts Sandblasting can clean the tiny burrs on the surface of the workpiece, make the surface of the workpiece more flat, eliminate the harm of burrs, and improve the grade of the workpiece. And sandblasting can make small rounded corners at the junction of the workpiece surface, making the workpiece more beautiful and more precise.

·sheetmetal.wiki Sheet Metal Fabrication Services include : Metal ShearingLaser Cutting,Sheet Metal Bending,Sheet Metal Punching,Sheet Metal Stamping,Sheet Metal Welding,Sheet Metal Tapping,Metal Grinding,CNC Drilling,Sheet Metal Molding,Sheet Metal Notching,Metal Finishing,Sheet Metal Assembly,Sheet Metal Riveting,Sheet Metal Design Assistance,Metal Finishing,

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What are the metal product processing technologies of precision sheet metal processing manufacturers

Precision sheet metal processing manufacturers CNC bending machines, etc. to produce sheet metal products. Can go directly from drawing to product paperless production. It is suitable for flexible production of small batches and multiple varieties. The sheet metal bracket is very powerful, and many sheet metal part features need more tedious operation steps to be realized under the modeling module. Three aspects of punch automation in sheet metal automation processing are briefly discussed.

Casting: Refers to the metalcastingbeing heated and melted and then poured into the model. It is suitable for processing parts with complex appearance.

Casting classification of sheet metal processing plants

Sand casting:

The cost is low, the batch size is small, and complex shapes can be processed, but it may require a lot of post-processing steps.

Investment Casting/ Lost Wax Casting: This processing method has high continuity and degree, and can also be used to produce complex shapes. Under the premise of relatively low processing cost, it can achieve a very perfect appearance, which is suitable for mass production.

Injection casting method:

For machining complex shapes with high error. Due to the characteristics of the technology itself, no post-processing is required after the product is formed. However, the advantage of low cost can only be shown in the case of mass production.​​

Die castingmethod:

The processing cost is high, and the cost is reasonable only in the case of mass production. But the cost of the final product is relatively low and the error is relatively high. Can be used to produce parts with thinner walls.​​

Spin casting method:

Ideal for processing small parts, generally used in jewelry making. Rubber models can be used to reduce processing costs.

Directional curing:

It can produce a very strong superalloy with anti-fatigue function and pour it into the model, and then go through a strictly controlled heating and cooling process to eliminate subtle flaws.

Plastic forming processing: refers to heating the formed metal at high temperature to reshape it, which is a labor-intensive production.

Plastic forming processing classification:

Casting:

It is one of the simple and old metal forming techniques to give metal shapes by beating and kneading under the conditions of cold working or high temperature operation. The sheet metal bracket is very powerful, and many sheet metal part features need more tedious operation steps to be realized under the modeling module.​​

Binding:

The hot metal billet is passed through a series of cylindrical rollers, which plunge the metal into the mold to obtain a predetermined shape.

Drawing wire:

The technique of drawing metal strips into filaments using a series of standard progressively smaller drawing dies.​​

Knead:

A low-cost technology for continuous machining of solid or hollow metal profiles with the same cross-sectional shape, capable of both high temperature operation and cold working. All or most of the CNC sheet metal processes use CNC equipment, such as CNC punching machines, CNC laser cuttingmachines, CNC bendingmachines, etc. to produce sheet metal products. It can achieve high product accuracy and reduce development time. Can go directly from drawing to product paperless production. It is suitable for flexible production of small batches and multiple varieties.

Impact Kneading:

Technology for machining small to medium standard parts that do not require a chimney taper. It is easy to produce and can process parts with various wall thicknesses. The processing cost is low.​​

Powder metallurgy:

A technology that can process ferrous metal components as well as non-ferrous metal components. It includes two basic processes of mixing the alloy powder and pressing the mixture into the mold. Metal particles are sintered and formed by high temperature heating. This technology does not require machining, and the raw material utilization rate can reach 97%. Different metal powders can be used to fill different parts of the mold.

Solid Forming Processing

Solid molding processing:

Refers to the materials used are some metal strips, sheets and other solid shapes that can be shaped at room temperature. Attributable to labor-intensive production. The processing cost can be relatively low. Classification of solid molding processing

Spinning:

A very common machining method used to produce circular symmetrical parts such as saucers, cups and cones. During processing, the high-speed rotating metal plate is pushed close to the model on the fixed lathe that rotates at the same time to obtain a preset appearance. This technology is suitable for the production of various batch methods.​​

Twists and turns:

An economical production technology for sheet, rod and tubular materials for processing methods.​​

Consecutive forming:

The metal sheet is fed between the press rollers to obtain a metal profile with continuous length and uniform cross-section. Similar to the kneading technique, but with constraints on the wall thickness of the processing element, only a single wall thickness can be obtained. Only under the premise of a lot of production, the processing cost is only.​​

Stamping:

The metal sheet is placed between the male mold and the female mold and is formed by restricting it, which is used to process the hollow shape, and the depth can be deep or shallow.

Punching:

The technology of punching and cutting a certain shape on a metal sheet using a special tool is suitable for both large and small batch production.

Punching:

It is basically similar to punching technology, the difference is that the former uses some punching, while the latter uses punching to leave some metal pieces. Three aspects of punch automation in sheet metal automation processing are briefly discussed.​​

Cut:

Laser cutting the metal sheet with a shearing method is the same as using a pair of scissors to remove the paper from the position.

Chip forming:

When cutting metal, the cutting method that produces chips is collectively referred to as chip forming, including milling, drilling, lathe processing, grinding, sawing and other technologies.​​

Chip-free molding:

Precision sheet metal processing manufacturers use existing metal strips or metal sheets to shape. No chipping occurs. Such techniques include chemical machining, etching, electrical discharge machining, sandblasting, laser cutting, water jet cutting, and thermal cutting.

·sheetmetal.wiki Sheet Metal Fabrication Services include : Metal ShearingLaser Cutting,Sheet Metal Bending,Sheet Metal Punching,Sheet Metal Stamping,Sheet Metal Welding,Sheet Metal Tapping,Metal Grinding,CNC Drilling,Sheet Metal Molding,Sheet Metal Notching,Metal Finishing,Sheet Metal Assembly,Sheet Metal Riveting,Sheet Metal Design Assistance,Metal Finishing,

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What are the technical requirements for precision casting


Let's take sand casting as an example. Factories that mass-produce precision casting should create conditions to adopt technologically advanced modeling and core-making methods. The old-fashioned shock or shock molding machine production line is not high enough in productivity, labor-intensive, and noisy, and cannot meet the requirements of mass production, so it should be gradually transformed. For small castings, a boxless high-pressure molding machine production line with horizontal or vertical parting can be used, which has high production efficiency and small footprint for solid molding; for medium parts, various boxed high-pressure molding machine production lines, gas Punching molding line to meet the requirements of fast and high-precision molding production line, core making methods can be selected: cold core box, hot core box, shell core and other efficient core making methods, and medium-volume large castings can be considered to use resin no-bake sand Shape and core.


For heavy-duty castings produced in small batches, die casting mold is still an important method. Manual molding can adapt to various complex requirements and is more flexible, and does not require a lot of process equipment. It can be applied to water glass sand mold, VRH water glass sand mold, organic ester water glass self-hardening sand mold, clay dry mold, resin self-hardening sand mold and cement sand mold, etc. For heavy castings produced in a single piece, the pit molding method is low in cost and can be put into production. quick. For mass-produced or long-term shaped products, it is more appropriate to use multi-box molding and split-box molding methods. Although the initial investment in molds and sand boxes is high, it can be compensated from the reduction of molding man-hours and the improvement of product quality.


Casting methods such as low pressure casting, die casting and centrifugal casting are only suitable for mass production due to expensive equipment and molds.


Conditional method should be suitable


For example, in the production of castings such as the bed of a large machine tool, the core forming method is generally used, instead of making the pattern and the sand box, the core is assembled in the pit; while other factories use the sand box molding method to make the pattern. Different enterprises have different production conditions (including equipment, site, staff quality, etc.), production habits, and accumulated experience. According to these conditions, it is necessary to consider what products are suitable and what products are not suitable (or cannot).


Accuracy Requirements and Costs


The accuracy of castings obtained by various casting methods is different, the initial investment and productivity are also inconsistent, and the final economic benefits are also different. Therefore, in order to achieve more, faster, better and more economical, all aspects should be taken into account. A preliminary cost estimate should be made for the casting method chosen to determine the most cost-effective casting method that will meet the casting requirements.


Experts said that in order to fundamentally improve the level of casting technology, the following four points must be achieved:

First, develop simulation technology to improve prediction accuracy, strengthen process control, and improve yield. The problem of regularity is not well grasped, which affects the yield in mass production.


Second, the combination of production, education and research. Independent innovation of enterprises In addition to the enhancement of innovation awareness and the improvement of research and development capabilities, it is also necessary to pay attention to and strengthen the combination of "production, learning and research" with precision casting enterprises as the main body.


Third, attach importance to material research and development. Materials are the foundation of industry, and there is still a lot of work to be done. In the field of aerospace, the research and smelting technology of alloy materials, especially some new materials such as superalloys, still needs to be improved, and there is still a big gap with foreign countries.


Fourth, pay attention to the improvement of equipment technology. The process is mainly a problem of equipment. Many key equipment, such as some directional solidification equipment, mainly rely on imports. Therefore, the research and development of precision casting equipment and die casting company are still the focus.

Copyright notice: This article comes from https://invest-casting.com/



What are the advantages and disadvantages of stainless steel precision casting process?


Analysis of the advantages and disadvantages of stainless steel precision casting processing technology:

Friends in the foundry industry know that the mechanical properties of stainless steel precision casting are higher than that of cast iron, but its casting performance is worse than that of cast iron, which is called investment precision casting or precision casting. Its melting point is relatively high, and the molten steel is easily oxidized, the fluidity of molten steel is poor, and the shrinkage is large. In fact, from a practical point of view, stainless steel precision tube casting is not only suitable for casting of various types and alloys.


Then the editor will explain to you the advantages and disadvantages of the stainless steel precision casting process: First of all, due to the poor fluidity of the molten steel, in order to prevent the cold insulation and insufficient pouring of the silicone casting, the wall thickness of the steel castings is It cannot be less than 8 mm; the structure of the pouring system is simple, and the cross-sectional size is larger than that of cast iron; dry casting or hot casting is used; the pouring temperature is appropriately increased, generally 1520 ° ~ 1600 ° C, because the pouring temperature is high, the molten steel The degree of superheat is large, the time of keeping the liquid state is long, and the fluidity can be improved.


However, if the pouring temperature is too high, it will cause defects such as coarse grains, thermal cracking, pores and sticky sand. Therefore, for small, thin-walled and complex-shaped castings, the pouring temperature is about the melting point temperature of steel + 150 °C; the pouring temperature of large and thick-walled castings is about 100 °C higher than the melting point.


In order to prevent the occurrence of shrinkage holes and cracks in stainless steel precision castings, we must take these measures to make the wall thickness uniform, and avoid sharp and right-angle structures. In addition, sawdust should be added to the mold for casting. , add coke in the core, and finally need to use a hollow core and an oil sand core to change the concession and permeability of the sand or core. As long as you follow what I've said, you'll be able to achieve the desired effect.

Copyright notice: This article comes from https://invest-casting.com/


What is a casting ?


The method of casting liquid metal into a casting cavity suitable for the shape of the part, and after the casting is cooled and solidified, is called casting. Castings obtained by casting are called castings.


Casting structure design: ensure its working performance and mechanical performance requirements, consider the requirements of casting process and alloy casting performance on the casting structure, and whether the casting structure design is reasonable or not has a great impact on the quality, productivity and cost of the casting.


Design main issues and design requirements


The design of the box should first consider the arrangement of the parts in the box and the relationship with the external parts of the box. For example, the shape and size of the box should be determined according to the requirements of the two tops of the lathe. In addition, the following issues should be considered:


⑴, to meet the strength and stiffness requirements. For box parts that are under great stress, meeting the strength is an important issue; but for most boxes, the main indicator for evaluating performance is stiffness, because the stiffness of the box not only affects the normal operation of the transmission parts, but also affects the components. Working precision. Quick and easy automatic selection of castings is included.


⑵, heat dissipation performance and thermal deformation problems. The friction and heat of the parts in the box will change the viscosity of the lubricating oil and affect its lubricating performance; the temperature rise will cause thermal deformation of the box, especially the thermal deformation and thermal stress with uneven temperature distribution, which have a great impact on the accuracy and strength of the box. influences.


3. The structure design is reasonable. Such as the arrangement of the fulcrum, the arrangement of the ribs, the position of the opening and the design of the connection structure, etc., are all conducive to improving the strength and rigidity of the box.


⑷, good craftsmanship. Including blank manufacturing, machining and heat treatment, assembly adjustment, installation and fixation, hoisting and transportation, maintenance and repair and other aspects of craftsmanship.


⑸, good shape, small quality.


What is casting process?


Casting generally does not apply pressure, does not require high strength of equipment and molds, has small restrictions on product size, and has low internal stress in products. Therefore, the production investment is less, and large-scale parts with excellent performance can be obtained, but the production cycle is long, and mechanical processing must be carried out after molding. On the basis of traditional casting, methods such as pouring, invest casting, pressure casting, spin casting and centrifugal casting are derived.


①Perfusion. The difference between this method and casting is that the product is released from the mold after casting, while the mold is an integral part of the product itself during pouring.


② Embedded casting. Various non-plastic parts are placed in the mold cavity and solidified with the injected liquid material to encapsulate them.


③Pressure casting. Applying a certain pressure to the material during casting is conducive to injecting the viscous material into the die casting mold and shortening the filling time. It is mainly used for epoxy resin casting.


④ Spin casting. After the material is injected into the mold, the mold rotates around a single axis or multiple axes at a low speed, and the material is distributed on the inner wall of the mold cavity by gravity, and shaped by heating and curing. For the manufacture of spherical, tubular and other hollow products.


⑤ Centrifugal casting. A quantitative liquid material is injected into a mold that rotates at a high speed around a single axis and can be heated, and the material is distributed on the inner wall of the mold cavity by centrifugal force, and is solidified into a tubular or hollow cylindrical product by physical or chemical action (see Figure [centrifugation]. casting]). Monolithic cast nylon parts can also be formed by centrifugal casting.

Copyright notice: This article comes from https://metalcasting.net/



What are the characteristics and main applications of aluminum alloy casting?

Aluminum alloy has low density, but relatively high strength, close to or surpassing high-quality steel, good plasticity, can be processed into various profiles, has excellent electrical conductivity, thermal conductivity and corrosion resistance, widely used in industry, and its usage is second only to steel . The following editor will introduce to you the characteristics and main applications of aluminum alloy casting.

Features of aluminum alloy casting:

1) Good fluidity to fill the narrow part of the slot.

2) It has a lower melting point than ordinary metals, but it can meet the requirements of most situations.

3) Good thermal conductivity, the heat of molten aluminum can be quickly transferred to the casting mold, and the casting cycle is short.

4) Hydrogen and other harmful gases in the melt can be effectively controlled by treatment.

5) When aluminum alloy is cast, there is no tendency of hot brittle cracking and tearing.

6) Good chemical stability and strong corrosion resistance.

7) It is not easy to produce surface defects, the surface of the casting has good surface finish and gloss, and it is easy to carry out surface treatment

8) Casting aluminum alloy machining has good processing performance. It can be used for casting production by pressing mold, hard mold, green sand and dry sand mold, investment plaster mold, vacuum casting, low pressure and high pressure casting, squeeze casting, semi-solid casting. Casting, centrifugal casting and other methods are used to form various castings with different uses, different specifications and different properties. Cast aluminum alloys are widely used in cars, such as engine cylinder heads, intake manifolds, pistons, wheel hubs, steering booster housings, etc.

What are the main applications of aluminum alloy casting?

Casting aluminum alloy is an die casting alloy that fills the mold with molten metal and obtains blanks of various shapes. It has the advantages of low density, high specific strength, good corrosion resistance and casting manufacturability, and is less restricted by the structural design of parts. Divided into Al-Si and Al-Si-Mg-Cu-based medium-strength alloys; Al-Cu-based high-strength alloys; Al-Mg-based corrosion-resistant alloys; Al-Re-based heat-strength alloys. Most require heat treatment to strengthen alloys, eliminate internal stress in castings, stabilize microstructure and part size. Used to manufacture beams, gas turbine blades, pump bodies, pylons, hubs, air intake lip and engine casings, etc. It is also used in the manufacture of automobile cylinder heads, gearboxes and pistons, instrumentation housings and supercharger pump parts.

Casting aluminum alloy has good casting properties, and can be made into parts with complex shapes; it does not require huge additional equipment; it has the advantages of saving metal, reducing costs, and reducing man-hours, and is widely used in the aviation industry and civil industry. Used to manufacture beams, gas turbine blades, pump bodies, pylons, hubs, air intake lip and engine casings, etc. It is also used in the manufacture of automobile cylinder heads, gearboxes and pistons, instrumentation housings and supercharger pump parts.

Copyright notice: This article comes from https://invest-casting.com/

The basic principle of heat treatment of cast aluminum alloy


(1) Annealing: The aluminum alloy gravity casting product is heated to a certain temperature and kept for a certain period of time, and then cooled to room temperature at a certain cooling rate. Through atomic diffusion and migration, the organization is made more uniform and stable, and the internal stress is eliminated, which can greatly improve the plasticity of the material, but the strength will be reduced.


(2) Solution quenching treatment: Heat the heat-treatable-strengthened cast aluminum alloy materials (such as A356, LM25, ZL101A, A357, ZL104, etc.) to a higher temperature and keep it for a certain period of time, so that the second phase or Other soluble components are fully dissolved in the aluminum matrix to form a supersaturated solid solution, and then the supersaturated solid solution is kept to room temperature by means of rapid cooling. It is an unstable state. There is a possibility of precipitation. However, at this time, the material has high plasticity and can be cold worked or straightened.

(3) Aging: The aluminum alloy die casting alloy parts after solution quenching are kept at room temperature or higher temperature for a period of time, the unstable supersaturated solid solution will decompose, and the second phase particles will be precipitated from the supersaturated solid solution ( or precipitation), distributed around the α(AL) aluminum grains, resulting in a strengthening effect called precipitation (precipitation) strengthening.


a. Natural aging: Some alloys (such as ZL301, etc.) can produce precipitation strengthening at room temperature, which is called natural aging.


b. Artificial aging: Some alloys (such as A356, etc.) do not have obvious precipitation strengthening at room temperature, but the precipitation strengthening effect is obvious at higher temperatures, which is called artificial aging.


Artificial aging can be divided into under-aging and over-aging.


①Unaging: In order to obtain a certain performance, control a lower aging temperature and maintain a shorter aging time.


②Over-aging: In order to obtain some special properties and better comprehensive properties, aging is carried out at a higher temperature or under a longer heat preservation time.


③Multi-stage aging: In order to obtain some special properties and good comprehensive properties, the aging process is divided into several stages. It can be divided into two-stage and three-stage aging

Copyright notice: This article comes from https://metal-spring.com/


The difference between gravity casting and sand casting and die casting

Gravity casting refers to a process in which molten metal is injected into a mold under the action of the earth's gravity, also known as casting. Gravity casting in a broad sense includes sand casting, metal casting, investment casting, lost foam casting, mud casting, etc.; gravity casting in a narrow sense refers to metal casting.

1. There are many process methods for making metal materials into desired products, such as casting, forging, extrusion, rolling, drawing, stamping, cutting, powder metallurgy and so on. Among them, casting is the most basic and most commonly used process.

2. The molten metal is poured into a hollow mold made of high-temperature resistant materials, and after condensation, a product of the desired shape is obtained, which is casting. The resulting product is a casting.

3. Casting can be divided into ferrous metal casting (including cast iron, cast steel) and non-ferrous metal casting (including aluminum alloy, copper alloy, zinc alloy, magnesium alloy, etc.) according to the material of the casting. The precision casting factory specializes in non-ferrous metal casting, with an emphasis on aluminum and zinc alloy casting.

4. Casting can be divided into sand casting and metal casting according to the material of the casting mold. The precision casting factory is handy with both casting processes, and designs and manufactures these two types of casting molds by themselves.

5. Casting can also be divided into gravity casting and die casting according to the casting process of molten metal. Gravity casting refers to a process in which molten metal is injected into a mold under the action of the earth's gravity, also known as casting. Gravity casting in a broad sense includes sand casting, metal casting, investment casting, lost foam casting, mud casting, etc.; gravity casting in a narrow sense refers tometal casting. Die casting refers to a process in which molten metal is injected into a mold under the action of other external forces (excluding gravity). Die casting in a broad sense includes pressure casting and vacuum casting of die casting machines, low pressure casting, centrifugal casting, etc.; pressure casting in a narrow sense refers to metal die casting of die casting machines, referred to as die casting. The precision casting factory has long been engaged in the gravity casting of sand and metal molds. These casting processes are currently the most commonly used in non-ferrous metal casting and are also the cheapest in relative price.

6. Sand casting is a traditional casting process that uses sand as the main molding material to make molds. Sand molds generally use gravity casting, and low-pressure casting, centrifugal casting and other processes can also be used when there are special requirements. Sand casting has a wide range of adaptability, small parts, large parts, simple parts, complex parts, single parts and large batches can be used. The molds for sand casting were mostly made of wood in the past, commonly known as wood molds. In order to change the disadvantages of wood molds, such as easy deformation and damage, Xudong Precision Casting Factory changed all the sand mold castings produced by a single piece to aluminum alloy molds or resin molds with high dimensional accuracy and long service life. Although the price has increased, it is still much cheaper than the mold used for metal mold casting. In the production of small batches and large pieces, the price advantage is particularly prominent. In addition, sand molds are more refractory than metal molds, so materials with higher melting points such as copper alloys and ferrous metals are also mostly used in this process. However,sand casting also has some disadvantages: because each sand casting can only be poured once, the casting is damaged after the casting is obtained and must be reshaped, so the production efficiency of sand casting is low; and because the overall nature of the sand is soft And porous, so sand casting castings have lower dimensional accuracy and rougher surfaces. However, the precision casting factory has accumulated many years of technology accumulation, which has greatly improved the surface condition of sand castings, and the effect after shot blasting is comparable to that of metal castings.

7. Metal mold casting is a modern process of making hollow casting molds from heat-resistant alloy steel. Metal molds can be either gravity casting or die casting. The casting mold of the metal mold can be used repeatedly. Every time the molten metal is poured, a casting is obtained, with a long service life and high production efficiency. The casting of the metal mold not only has good dimensional accuracy and smooth surface, but also has a higher strength than the sand mold under the condition of pouring the same molten metal, and is less likely to be damaged. Therefore, in the mass production of medium and small castings of non-ferrous metals, as long as the melting point of the casting material is not too high, metal mold casting is generally preferred. However, metal mold casting also has some disadvantages: because the heat-resistant alloy steel and the processing of hollow cavities on it are relatively expensive, the mold cost of the metal mold is high, but the overall cost of the die-casting molding is lower than that of the die-casting mold. too much. For small batch production, the mold cost allocated to each product is obviously too high, which is generally not acceptable. And because the mold of the metal mold is limited by the size of the mold material and the capacity of the cavity processing equipment and casting equipment, it is also powerless for particularly large castings. Therefore, in the production of small batches and large pieces, metal mold casting is rarely used. In addition, although the metal mold adopts heat-resistant alloy steel, its heat resistance is still limited. Generally, it is mostly used in the casting of aluminum alloys, zinc alloys, and magnesium alloys. even less. All the metal molds of Xudong Precision Casting Factory are designed and manufactured by themselves, so they can provide customers with cheap and suitable high-quality molds in a timely manner.

8. Die casting is the metal mold pressure carried out on the die casting machine, and it is the casting process with the highest production efficiency at present. Die-casting machines are divided into two categories: hot-chamber die-casting machines and cold-chamber die-casting machines. The hot chamber die casting machine has a high degree of automation, less material loss, and higher production efficiency than the cold chamber die casting machine. However, due to the restriction of the heat resistance of the parts, it can only be used for the production of low melting point materials such as zinc alloy and magnesium alloy. . The aluminum alloy die castings that are widely used today can only be produced on cold chamber die casting machines due to their high melting point. The main feature of die casting is that the molten metal fills the cavity under high pressure and high speed, and is formed and solidified under high pressure. The air in the cavity is wrapped inside the casting to form subcutaneous pores, so the die casting alloys hould not be heat treated, and the zinc alloy die casting should not be sprayed on the surface (but it can be painted). Otherwise, the internal pores of the casting will expand due to thermal expansion and cause the casting to deform or bubble when the above-mentioned treatment is performed. In addition, the machining allowance of die castings should also be smaller, generally around 0.5mm, which can not only reduce the weight of castings, reduce the amount of cutting to reduce costs, but also avoid penetrating the surface dense layer and exposing subcutaneous pores, causing The workpiece is scrapped.

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