The process of creating empty spaces or components by pouring molten metal into a molding cavity that matches the shape and size of the desired part, and allowing it to cool and solidify, is commonly referred to as the formation or casting of liquid metal.

Processing flow: Liquid metal –> mold filling –> solidification & contraction –> casting

Processing characteristics:

1. Capable of manufacturing components with intricate designs, particularly within enclosed spaces.
2. The adaptability is robust, with a wide range of alloy categories and unrestricted casting sizes.
3. Extensive range of materials, leftover pieces that are capable of being melted again, and affordable equipment costs.
4. The prevalence of waste material, subpar surface finish, and unfavorable working conditions are prevalent issues in this context.

Casting category:

Sand casting

Sand casting is a technique used to produce castings in sand molds, allowing for the creation of steel, iron, and various nonferrous alloy castings.

Processing flow:

Technical features

1. Ideal for creating intricate shapes, particularly within cavities.
2. Extensive versatility at an affordable price.
3. Sand casting is the sole forming process available for producing parts or blanks from materials that have limited plasticity, like cast iron.

Application: Components such as the engine cylinder block, cylinder head, crankshaft, and other castings are commonly utilized in the manufacturing of automobiles.

Investment Casting

A commonly known casting method, referred to as “dewaxing casting,” utilizes a fusible material to create a pattern. Multiple layers of refractory material are then applied to form a shaping shell. The pattern is subsequently melted, leaving behind an integrated casting mold. This mold is then subjected to high temperatures and can be utilized for casting through sand filling.

Processing flow:

Processing advantages

1. Exceptional accuracy in dimensions and shape.
2. Elevated surface roughness.
3. Have the capability to manufacture castings with intricate external shapes regardless of the cast alloy used.

Processing disadvantages

1. Complex processes and increased expenses.

Small parts with intricate shapes and high accuracy can be produced using these applications, especially those that are impossible to manufacture through other methods, like turbo engine blades.

Die Casting

The casting is formed when high-speed, high-pressure metal liquid is injected into a precise metallic mold cavity. The metal liquid then cools and solidifies within the mold, resulting in the formation of the casting.

Processing flow:

Processing advantages

1. Exceptional accuracy in dimensions and shape.
2. The product exhibits high quality, consistent sizing, and excellent interchangeability.
3. Enhanced efficiency and increased longevity of the die.
4. Ideal for mass production, offers significant cost advantages.

Processing disadvantages

1. The castings typically exhibit small air voids and shrinkage porosity.
2. Die casting is known for its limited malleability and is unsuitable for environments that experience high impact loads and shocks.
3. The die casting of high melting point alloy is limited by the shorter service life of the die, thus hindering the growth of die-casting production.

Die casting applications were first utilized in the automobile and instrument industries before expanding to various other sectors including agricultural machinery, machine tools, electronics, national defense, computers, medical devices, timepieces, cameras, and everyday hardware.

Low Pressure Casting

Casting is produced by crystallization under pressure when liquid metal is poured into a die mold at a relatively low pressure (0.02～0.06MPa).

Processing flow:

Technical features

1. The casting process allows for the adjustment of pressure and speed, making it suitable for a wide range of casting molds including metal and sand molds. It can be utilized to cast different alloys and create castings of varying sizes.
2. By utilizing the bottom filling method, the metal liquid is smoothly filled without splashing, preventing the entry of air and minimizing flushing to the walls and cores. This ultimately enhances the accuracy of the castings.
3. The solidification process occurs under pressure, resulting in a compact structure with a distinct profile, sleek surface, and excellent mechanical characteristics. This is particularly advantageous for producing thin-wall castings.
4. The removal of the feeding head has resulted in an increase in metal utilization to 90-98%.
5. Low workforce requirements, improved labor conditions, uncomplicated machinery, and the ease of attaining mechanization and automation.

Application It is mainly focused on traditional products (cylinder head, hub and cylinder rack).

Centrifugal Casting

Pouring molten metal into a spinning casting mold to use centrifugal force for filling the mold and shaping the metal into desired forms.

Processing flow:

Processing advantages

1. The consumption of metal in both the pouring system and the feeding-head system is minimal, leading to enhanced productivity in the overall process.
2. The omission of the mold core in the production of hollow castings allows for a significant enhancement in the metal-filling capacity, particularly in the manufacturing process of elongated tubular castings.
3. The casting produced exhibits high density and excellent mechanical properties, with minimal porosity and inclusions.
4. Composite metal castings can be effectively utilized in the production of sleeves or bushings.

Processing disadvantages

1. The production of special-shaped castings is somewhat restricted.
2. The casting exhibits an imprecise bore diameter, a rough internal surface, subpar quality, and a larger margin for machining.
3. Gravity segregation can be effortlessly achieved during the casting process.

Centrifugal casting has been historically utilized for the production of cast tubes. This method is employed in the manufacturing of steel, iron, and nonferrous carbon alloy castings that are essential in various industries including metallurgy, mining, transportation, drainage and irrigation machinery, aviation, national defense, automotive, among others. It is predominantly known for producing castings like centrifugal cast tubes, cylinder liners, and shaft sleeves that are utilized in internal combustion engines.

Gravity die casting

A technique for creating castings involves the process of pouring molten metal into a metallic mold and allowing it to solidify through the force of gravity within the mold.

Processing flow:

Processing advantages

1. Metal molds possess superior heat conductivity and capacity, expedited cooling capabilities, a compact casting structure, and exhibit a mechanical property that is approximately 15% greater than that of sand casting.
2. Achieve a casting with enhanced precision in size and reduced surface roughness, along with excellent quality consistency.
3. The limited use of sand core contributes to environmental improvement by reducing dust and harmful gases, as well as lowering labor intensity.

Processing disadvantages

1. It is necessary to take steps to remove air from the mold cavity and gases from the sand core due to the airtight nature of the metallic mold.
2. During the solidification process of casting, the non-flexible metallic mold often develops cracks.
3. Metal molds undergo a lengthier production process and incur higher expenses. As a result, more favorable financial outcomes are only evident in mass production.

The metallic mold application is suitable for mass producing nonferrous alloy castings, including aluminum alloy and magnesium alloy components with intricate designs, as well as steel and iron castings or ingots.

Vacuum Die Casting

A sophisticated die casting technique is employed to enhance the mechanical characteristics and surface integrity of castings by eliminating gas from the mold cavity or significantly reducing the porosity or dissolved gas within the casting.

Processing flow:

Processing advantages

1. To enhance the mechanical properties and surface quality of the casting, as well as optimize the coating performance, it is imperative to minimize or diminish the presence of porosity within the casting.
2. It is feasible to produce larger castings using a smaller machine by reducing the counter pressure in the mold cavity and utilizing an alloy with lower specific pressure and inferior casting performance.
3. It is feasible to produce thinner castings with enhanced filling condition.

Processing disadvantages

1. It is feasible to produce thinner castings with enhanced filling condition.
2. Improper control of vacuum die casting may lead to insignificant results.

Squeezing die casting

The process of extracting the part or blank directly from liquid or semi-solid metal that solidifies or flows to shape under intense pressure is a metal-forming method that shows promise for use because of its efficient liquid metal utilization, straightforward process, and consistent quality.

Processing flow:

Direct squeezing die casting

Apply spray coating, pour alloy, close mold, pressurize, maintain pressure, release pressure, open mold, remove blank, reset.

Indirect squeeze die casting involves a series of steps: applying a coating spray, closing the mold, feeding the material, filling the mold, applying pressure, maintaining pressure, releasing pressure, opening the mold, removing the blank, and resetting the process.

Technical features

1. Internal air pockets, gaps, and shrinkage porosity can be eradicated.
2. Achieving a smooth surface finish and precise dimensions.
3. It is possible to avoid cracks resulting from the casting process.
4. Mechanization and automation can be easily accomplished.

Application: It has the capability to generate a wide range of alloys, including aluminum alloy, zinc alloy, copper alloy, and nodular cast iron.

Lost foam casting

Lost foam casting, also referred to as the full mold process, is a cutting-edge casting technique. It involves the utilization of wax or foam models that are shaped and sized similarly to the desired casting. These models are bonded together, coated with a refractory material, and then dried using heat. Subsequently, they are buried in dry quartz sand and compacted through vibration. The next step involves pouring liquid metal under negative pressure, which causes the models to gasify. As a result, the liquid metal fills the void left by the models. Finally, the metal cools and solidifies, resulting in the formation of the desired casting.

Processing flow:

Pre-foaming -> Foam molding -> dipping in paint arrow-right drying -> shaping -> pouring -> shakeout -> clearing

Technical features

1. The processing time is reduced due to the absence of sand core, resulting in high casting precision.
2. The design offers a high level of flexibility and freedom due to the integration of the mold surface.
3. Production that is free from any form of contamination is essential for maintaining cleanliness and ensuring the quality of the final product.
4. Decrease in investment and production expenses.

Application It is suitable for production of precise castings with complicated structure, in various sizes, without limitation to alloy species and batches of production, such as gray pig iron engine housing and high manganese steel elbow.

Continual Casting

Continuous Casting is a sophisticated casting technique where molten metal is poured continuously into a specialized metallic mold known as a crystallizer. The solidified casting is continuously extracted from the opposite end of the crystallizer, allowing for the production of castings of varying lengths.

Processing flow:

Technical features

1. Due to the rapid cooling of metal, the casting exhibits dense crystallization, a uniform texture, and excellent mechanical properties.
2. Increased productivity and enhanced efficiency result in reduced metal usage and improved output.
3. The labor intensity has been significantly reduced due to the simplified procedure and exemption of shaping and other procedures. Additionally, there has been a considerable reduction in the required production area.
4. The continuous process of casting production facilitates the implementation of mechanization and automation, leading to enhanced productivity.

The continuous casting process is suitable for casting steel, iron, copper alloy, aluminum alloy, and magnesium alloy into elongated shapes like ingots, plate blanks, rod blanks, and pipes with uniform cross-sectional form.