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A wide range of casting alloyfacilitates selection of the most suitable and cost-effective material for specific application requirements. Each of these cast alloys has its own physical and mechanical properties. They also have their own casting features such as:
Solderability
machinability
Corrosion resistance
Heat treatment characteristics
Bronze is without a doubt the most versatile class of bearing materials, with a wide range of properties to choose from in a variety of alloys and compositions.
Furthermore, continuous research into alloying elements often leads to the invention and development of stronger and more suitable casting alloys to meet the demands of industrial applications. Choosing the right casting method and the most suitable alloy are two main factors that help to achieve a specific cost level.
There are two main categories of casting alloys:
ferroalloy
Ferrous alloys are iron-based alloys that have a wide range of uses in a wide range of industries due to their flexibility to meet strength, toughness and impact for a variety of industrial applications.
steel
The properties of steels determined by dispersion strengthening depend on the amount, size, shape and distribution of cementite (Fe3C).
These factors are controlled by alloying and heat treatment.
steel surface treatment
Surface heat treatment: The surface is rapidly heated, quenched, and then tempered.
Carburizing: Carbon diffuses to the surface to increase the carbon on the surface.
Nitriding: Similar to carburizing, but nitrogen (N) is used instead of carbon.
Stainless steel
Ferritic stainless steel (BCC): up to 30% Cr and less than 0.12% C. Good corrosion resistance.
Martensitic stainless steel: Cr < 17%. Heat treatable, able to form martensite in other phases.
Austenitic stainless steel (FCC): Ni is an austenitic stabilizing element.
cast iron
Grey cast iron: interconnected graphite flakes in a pearlite matrix. Vibration reduction effect is good.
White cast iron: Used for its high hardness and wear resistance. Martensite can be formed.
Malleable Iron: A heat treated unalloyed 3% carbon white cast iron.
Ductile Iron: The addition of magnesium (Mg) causes nodular graphite growth.
Non-ferrous alloys
Non-ferrous alloys are completely iron-free and are generally more expensive than ferrous alloys. Copper alloys are the largest product group of these alloys. Brass and bronze are the most popular copper alloys.
Brass made from copper and zinc alloys. Most varieties of brass are easy to form and have a pleasing appearance.
Copper is mainly alloyed with tin to make bronze.
Both cast iron and cast steel are Fe-C alloys. Due to the different contents of chemical elements such as carbon, silicon, manganese, phosphorus, and sulfur, they have different metallographic structures and exhibit many different mechanical properties and castability. It is generally believed that the carbon content of more than 2% is cast iron, and the carbon content of 0.1-0.5% is cast steel. Let's take a look at the differences between steel castings and iron castings according to their classification and applications.
cast iron
Grey cast iron. High carbon content (2.7% to 4.0%). Gray cast iron is the most widely used cast iron containing flake graphite (accounting for more than 80% of the total output of cast iron). Carbon is mainly flake graphite, gray, low melting point (1145 ~ 1250 ℃), small solidification shrinkage, compressive strength and hardness close to carbon steel, good shock absorption, used to manufacture machine bed, cylinder, box, etc. Structure.
Compacted graphite cast iron. It is obtained from grey cast iron treated with worms. The precipitated graphite is worm-like, between flakes and spheroids. Its chemical structure is similar to that of gray cast iron, its mechanical properties are similar to that of cast iron, and its castability is between gray cast iron and ductile iron.
Can be used to manufacture auto parts.
Ductile iron. The ductile iron obtained by spheroidization and inoculation to form gray cast iron water is called ductile iron. It has higher strength, better toughness and plasticity than ordinary gray cast iron.
Used in the manufacture of internal combustion engines, auto parts and agricultural machinery.
cast steel
Cast steel is an iron-carbon alloy with a carbon content below 2.11%. Cast steel has good comprehensive properties, weldability and workability, but compared with cast iron, its vibration absorption and casting properties are poor. Cast steel can be divided into cast carbon steel, cast low alloy steel and cast special steel according to chemical element composition.
Cast carbon steel. Cast steel with carbon as the main alloying element and small amounts of other elements. It can be divided into cast low carbon steel (with carbon content less than 0.2%), cast medium carbon steel (with carbon content of 0.2% to 0.5%), and cast high carbon steel (with carbon content greater than 0.5%). Its strength and hardness increase with increasing carbon content. Cast carbon steel has high strength, plasticity and toughness, and is low in cost. It is used in heavy machinery to produce parts with large loads, such as rolling mill stands, hydraulic press bases; manufacturing pillows, side frames, wheels and couplings on railway vehicles. Heavy-duty impact bearing parts such as shafts.
Cast low alloy steel. Cast steel containing manganese, chromium, copper and other alloying elements (total less than 5%). It has greater impact toughness and better mechanical properties can be obtained by heat treatment. Casting low alloy steel has better performance than carbon steel, which can reduce the quality of parts and increase the service life.
Cast special steel. Alloy cast steel refined for special needs. It usually contains a large amount of one or more alloying elements to obtain specific properties. For example, high manganese steel containing 11% to 14% manganese can withstand impact wear and is mostly used for wear-resistant parts of mining machinery and construction machinery; various stainless steels with chromium or chromium-nickel as the main alloying elements are used for valves in large-capacity power plants. Parts that are easy to corrode or work at high temperatures above 650°C, such as bodies, pumps, containers or turbine casings. chemical industry.
Generally speaking, cast iron has lower elongation, shrinkage and impact toughness than cast steel, and its compressive strength and shock resistance are also better than cast steel; cast iron is generally cheaper, while raw steel is more expensive because of material cost, energy and higher cost. The labor required to produce the final product. The main advantage of cast steel is design flexibility, which makes it ideal for parts with complex shapes and hollow cross-sections. They each have advantages and disadvantages, so the choice should be based on the application and its physical properties.
Both cast iron and cast steel are Fe-C alloys. Due to the different contents of chemical elements such as carbon, silicon, manganese, phosphorus, and sulfur, they have different metallographic structures and exhibit many different mechanical properties and castability. It is generally believed that the carbon content of more than 2% is cast iron, and the carbon content of 0.1-0.5% is cast steel. Let's take a look at the differences between steel castings and iron castings according to their classification and applications.
cast iron
Grey cast iron. High carbon content (2.7% to 4.0%). Gray cast iron is the most widely used cast iron containing flake graphite (accounting for more than 80% of the total output of cast iron). Carbon is mainly flake graphite, gray, low melting point (1145 ~ 1250 ℃), small solidification shrinkage, compressive strength and hardness close to carbon steel, good shock absorption, used to manufacture machine bed, cylinder, box, etc. Structure.
Compacted graphite cast iron. It is obtained from grey cast iron treated with worms. The precipitated graphite is worm-like, between flakes and spheroids. Its chemical structure is similar to that of gray cast iron, its mechanical properties are similar to that of cast iron, and its castability is between gray cast iron and ductile iron.
Can be used to manufacture auto parts.
Ductile iron. The ductile iron obtained by spheroidization and inoculation to form gray cast iron water is called ductile iron. It has higher strength, better toughness and plasticity than ordinary gray cast iron.
Used in the manufacture of internal combustion engines, auto parts and agricultural machinery.
cast steel
Cast steel is an iron-carbon alloy with a carbon content below 2.11%. Cast steel has good comprehensive properties, weldability and workability, but compared with cast iron, its vibration absorption and casting properties are poor. Cast steel can be divided into cast carbon steel, cast low alloy steel and cast special steel according to chemical element composition.
Cast carbon steel. Cast steel with carbon as the main alloying element and small amounts of other elements. It can be divided into cast low carbon steel (with carbon content less than 0.2%), cast medium carbon steel (with carbon content of 0.2% to 0.5%), and cast high carbon steel (with carbon content greater than 0.5%). Its strength and hardness increase with increasing carbon content. Cast carbon steel has high strength, plasticity and toughness, and is low in cost. It is used in heavy machinery to produce parts with large loads, such as rolling mill stands, hydraulic press bases; manufacturing pillows, side frames, wheels and couplings on railway vehicles. Heavy-duty impact bearing parts such as shafts.
Cast low alloy steel. Cast steel containing manganese, chromium, copper and other alloying elements (total less than 5%). It has greater impact toughness and better mechanical properties can be obtained by heat treatment. Casting low alloy steel has better performance than carbon steel, which can reduce the quality of parts and increase the service life.
Cast special steel. Alloy cast steel refined for special needs. It usually contains a large amount of one or more alloying elements to obtain specific properties. For example, high manganese steel containing 11% to 14% manganese can withstand impact wear and is mostly used for wear-resistant parts of mining machinery and construction machinery; various stainless steels with chromium or chromium-nickel as the main alloying elements are used for valves in large-capacity power plants. Parts that are easy to corrode or work at high temperatures above 650°C, such as bodies, pumps, containers or turbine casings. chemical industry.
Generally speaking, cast iron has lower elongation, shrinkage and impact toughness than cast steel, and its compressive strength and shock resistance are also better than cast steel; cast iron is generally cheaper, while raw steel is more expensive because of material cost, energy and higher cost. The labor required to produce the final product. The main advantage of cast steel is design flexibility, which makes it ideal for parts with complex shapes and hollow cross-sections. They each have advantages and disadvantages, so the choice should be based on the application and its physical properties.
Green sand is new or reclaimed sand mixed with natural or synthetic binders and is the most commonly used material for the manufacture of aluminum consumption molds. Wet sand molds get their name from the fact that they are still wet when molten metal is poured into them. The process flow of aluminum sand casting using green sand and gravity filling method can be summarized as follows:
A mold is created by placing a mixture of sand, clay and water on a model (a replica of the object to be cast). While this process can be done by hand, machinery is usually used for better mold accuracy. After removing the pattern, the clay will have cavities corresponding to the shape of the pattern
The sand mold has two or more parts, the upper part is called the upper part and the lower part is called the lower part. Additional parts called cheeks are also available. The molds are housed in a two-part (more if cheeks are used) box called a flask for protection. Any sand cores needed to create the detail of the part are placed in the mold halves before the flask is closed. The gating system is placed inside and forms a runner to feed the molten alloy into the casting
The halves are closed and clamped together, and the molten metal is poured into the mold. As the metal begins to cool and some shrinkage occurs, molten metal is fed from risers placed in the casting system
Because sand and clay do not absorb heat, the cooling time is much longer than permanent molds or die casting. Coolant (sheet metal) can be inserted into the sand mold to help provide the same cooling rate throughout the casting. Alloys such as Aluminum 319 and 356, Magnesium and Bronze have significantly reduced mechanical properties due to slower cooling rates compared to the same alloys cast using permanent or die casting methods based on secondary dendrite spacing between arms (SDAS) values
After a preset dwell time for the metal to solidify, the casting vibrates. The heat from the molten metal injected into it dries out the moisture, making the casting susceptible to cracking after the metal cools
Aluminium sand casting defects to be aware of are residual oxide film, inclusions, core erosion, porosity and shrinkage.
Aluminium sand casting components are widely used in the automotive and transportation industries, including aerospace. Parts typically produced in sand casting include drivetrains, brackets, suspensions, housings, gears, and more.