Article Guidance:

1.Sand casting

2.Investment casting

3.Die casting

4.Low pressure casting

5.Centrifugal casting

6.gravity die casting

7. Vacuum die casting

8.Squeeze die casting

9.Lost Foam Casting

10.Continuous casting

1.Sand casting

Sand casting: A casting method in which castings are produced in sand molds. Steel, iron and most non-ferrous alloy castings can be obtained by sand casting.

Process flow:

Technical Features:

It is suitable for making blanks with complex shapes, especially with complex inner cavities; 2. Wide adaptability and low cost; 3. For some materials with poor plasticity, such as cast iron, sand casting is the best way to manufacture parts or, The only forming process for blanks.

Application: Engine cylinder blocks, cylinder heads, crankshafts and other castings of automobiles

2.Investment casting

Investment casting: usually refers to making a pattern from a fusible material, coating several layers of refractory material on the surface of the pattern to make a shell, and then melting the pattern to discharge the shell, so as to obtain a mold without a parting surface, which is roasted at high temperature The casting scheme that can be filled with sand after pouring. Often referred to as "lost wax casting".

Process flow:

Process characteristics

Advantages: 1. High dimensional accuracy and geometric accuracy; 2. High surface roughness; 3. Can cast castings with complex shapes, and the casting alloys are not limited.

Disadvantages: complicated process and high cost

Application: It is suitable for the production of small parts with complex shapes, high precision requirements, or difficult other processing, such as turbine engine blades, etc.

3.Die casting

Die casting: It uses high pressure to press molten metal into a precision metal mold cavity at high speed, and the molten metal is cooled and solidified under pressure to form a casting.

Process flow:

Process characteristics

Advantages: 1. The metal liquid bears high pressure during die-casting, and the flow rate is fast. 2. The product quality is good, the size is stable, and the interchangeability is good; 3. The production efficiency is high, and the die-casting mold can be used more times; 4. It is suitable for mass production and has good economic benefits.

Disadvantages: 1. Castings are prone to tiny pores and shrinkage. 2. Die-casting parts have low plasticity, so it is not suitable to work under impact load and vibration; 3. When die-casting high-melting point alloys, the mold life is low, which affects the expansion of die-casting production.

Application: Die castings were first used in the automobile industry and the instrument industry, and later gradually expanded to various industries, such as agricultural machinery, machine tool industry, electronics industry, defense industry, computer, medical equipment, clocks, cameras, daily hardware and other industries .

4.Low pressure casting

Low-pressure casting: refers to the method of filling the mold with liquid metal under the action of lower pressure (0.02-0.06MPa) and crystallizing under pressure to form castings.

Process flow:

Technical Features:

1. The pressure and speed of pouring can be adjusted, so it can be applied to various casting molds (such as metal molds, sand molds, etc.), casting various alloys and castings of various sizes; The liquid filling is stable without splashing, which can avoid the gas involved and the erosion of the mold wall and core, which improves the qualified rate of castings; Higher performance, especially beneficial for the casting of large thin-walled parts; 4. The feeding riser is omitted, and the metal utilization rate is increased to 90-98%; 5. The labor intensity is low, the working conditions are good, the equipment is simple, and it is easy to realize mechanization and automation. Application: mainly traditional products (cylinder head, wheel hub, cylinder frame, etc.).

5.Centrifugal casting

Centrifugal casting: It is a casting method in which molten metal is poured into a rotating mold, and the mold is filled and solidified under the action of centrifugal force.

Process flow:

Process characteristics

Advantages: (1). There is almost no metal consumption in the gating system and riser system, which improves the process yield;

 (2). When producing hollow castings, no core is needed, so the metal filling ability can be greatly improved when producing long tubular castings ;

(3). The casting has high density, fewer defects such as pores and slag inclusions, and high mechanical properties;

(4). It is convenient to manufacture composite metal castings such as barrels and sleeves.

Disadvantages:

(1). There are certain limitations when used to produce special-shaped castings;

(2). The diameter of the inner hole of the casting is not accurate, the surface of the inner hole is rough, the quality is poor, and the machining allowance is large;

(3). Castings are prone to specific gravity segregation.

Application: Centrifugal casting was first used to produce cast pipes. At home and abroad, centrifugal casting technology is used in metallurgy, mining, transportation, drainage and irrigation machinery, aviation, national defense, automobile and other industries to produce steel, iron and non-ferrous carbon alloy castings. Among them, the production of castings such as centrifugal cast iron pipes, internal combustion engine cylinder liners and shaft sleeves is the most common.

6.gravity die casting

Metal mold casting: refers to a molding method in which liquid metal fills a metal mold under the action of gravity and cools and solidifies in the mold to obtain a casting.

Process flow:

Process characteristics

Advantages: (1). The thermal conductivity and heat capacity of the metal mold are large, the cooling speed is fast, the structure of the casting is compact, and the mechanical properties are about 15% higher than that of the sand casting.

(2). Castings with high dimensional accuracy and low surface roughness can be obtained, and the quality stability is good. 3. Because sand cores are not used or rarely used, the environment is improved, dust and harmful gases are reduced, and labor intensity is reduced.

Disadvantages: (1). The metal mold itself has no air permeability, and certain measures must be taken to export the air in the cavity and the gas generated by the sand core;

(2) . The metal mold has no concession, and cracks are prone to occur when the casting is solidified;

(3) . Metal mold manufacturing The cycle is longer and the cost is higher. Therefore, good economic effects can only be shown when mass-produced in large quantities.

Application: Metal mold casting is not only suitable for mass production of non-ferrous alloy castings such as aluminum alloys and magnesium alloys with complex shapes, but also for the production of iron and steel metal castings and ingots.

7. Vacuum die casting

Vacuum casting: an advanced die-casting process that improves the mechanical properties and surface quality of die-castings by eliminating or significantly reducing the pores and dissolved gases in die-castings by pumping out the gas in the die-casting mold cavity during the die-casting process.

Advantages: (1). Eliminate or reduce the pores inside the die casting, improve the mechanical properties and surface quality of the die casting, and improve the coating performance;

(2) . Reduce the back pressure of the cavity, and use lower specific pressure and poor casting performance Alloy, it is possible to die-cast larger castings with small machines;

(3) . Improve the filling conditions and die-cast thinner castings;

Disadvantages: (1). The mold sealing structure is complicated, and it is difficult to manufacture and install, so the cost is high;

(2) . If the vacuum die-casting method is not properly controlled, the effect will not be very significant.

8.Squeeze die casting

Squeeze casting: It is a method of solidifying liquid or semi-solid metal under high pressure, flow forming, and directly obtaining workpieces or blanks. It has the advantages of high utilization rate of liquid metal, simplified process and stable quality. It is an energy-saving metal forming technology with potential application prospects.

Process flow:

Direct extrusion casting: spray paint, cast alloy, mold clamping, pressurization, pressure maintaining, pressure relief, mold splitting, blank demoulding, reset;

Indirect squeeze casting: coating, mold clamping, feeding, filling, pressurization, pressure holding, pressure relief, mold parting, blank demoulding, reset.

Technical Features:

1. It can eliminate internal defects such as air holes, shrinkage cavities and shrinkage porosity; 2. Low surface roughness and high dimensional accuracy; 3. It can prevent casting cracks; 4. It is easy to realize mechanization and automation.

Application: It can be used to produce various types of alloys, such as aluminum alloy, zinc alloy, copper alloy, ductile iron, etc.

9.Lost Foam Casting

Lost foam casting (also known as solid casting): it is to bond and combine paraffin or foam models similar in size and shape to the castings to form a model cluster. It is a new casting method that the mold is vaporized by pressing down and pouring, and the liquid metal occupies the position of the mold, solidifies and cools to form a casting.

Process flow: pre-foaming→foaming molding→dipping paint→drying→modeling→pouring→shaking→cleaning

Technical Features:

1. The casting has high precision and no sand core, which reduces the processing time; 2. No parting surface, flexible design and high degree of freedom; 3. Clean production and no pollution; 4. Reduce investment and production costs.

Application: It is suitable for the production of precision castings of various sizes with complex structures. The types of alloys are not limited, and the production batches are not limited. Such as gray cast iron engine case, high manganese steel elbow, etc.

10.Continuous casting

Continuous casting: It is an advanced casting method. Its principle is to continuously pour molten metal into a special metal mold called a crystallizer, and the solidified (crusted) casting is continuously poured from the other side of the crystallizer. Pulled out at one end, it obtains castings of any length or a specific length.

Process flow:

Technical Features:

1. Due to the rapid cooling of the metal, the crystallization is dense, the structure is uniform, and the mechanical properties are better; 2. The metal is saved and the yield is improved; 3. The process is simplified, and the molding and other processes are exempted, thus reducing the labor intensity; the required production The area is also greatly reduced; 4. Continuous casting production is easy to realize mechanization and automation, and improves production efficiency.

Application: Continuous casting can be used to cast steel, iron, copper alloy, aluminum alloy, magnesium alloy and other long castings with constant cross-sectional shape, such as ingots, slabs, billets, pipes, etc.