Grey Iron Casting,Gray Iron Casting
Grey iron casting was produced by Chinese over 2,500 years ago. It is widely used in stoves,common household goods,tools,building materials, and statuary.Today, we are a modern Grey iron castings foundry company in China. Most of our Grey iron castings are exported to all over the world.In this article, we will introduce the WHAT IS THE GREY IRON CASTINGS?ITS PROCESS,BENEFITS, TYPES AND SIMILAR PROCESS OF CASTING.
What is Grey iron castings?
Grey iron castings,also called Gray Iron Casting, are a casting part which is typically made by smelting grey iron. It is one kind of Iron Casting. Grey iron is an alloy made of iron and carbon. It also possesses traces of phosphorous, sulfur, silicon and manganese in them.Since Grey iron, or grey cast iron, is a material type of cast iron with graphitic microstructure. So it is called grey iron because of the gray color of the fracture.
Grey iron can fill specific requirements for hardness and wear, and heat treatments can yield even higher mechanical properties. Because of its high thermal conductivity, strength, durability, machinability, and relatively low cost, grey iron is widely used for valves, engine blocks, brake drums, pump housings, and cast-iron cookware.
Grey iron casting is done in a foundry. Grey iron castings are made by pouring molten iron alloys into molds. The finished iron casting may be machined, but grey iron cannot be forged or extruded at any temperature, so it must be cast.
Our main process method of Grey Iron Castings
Commonly used grey iron castings process in the market is produced by sand casting. In our foundry, we can make grey iron castings by two types:
Type 1: Lost Foam Casting
The only investment casting process for cast iron components, which has lots of advantages to produce small gray iron invesmtent castings, such as saved mould cost, shorten production cycle and improve production efficiency. With lost foam casting process, we can help our customers to obtain high accuracy products with excellent surface finish, and less machining operations will be done.
Type 2: Resin Sand Casting
Main sand casting process for small and medium castings. Compare with other sand casting processes, resin sand casting is relatively precise casting method close to investment casting. As good rigidity of resin sand and high strength of sand mould when early casting,then we could effectively eliminate the shrinkage cavity, shrinkage defects of gray iron castings.
Heat Treatment of Grey Iron Castings
Most of the time, grey iron castings are supplied to our customers in the as-cast condition directly. But For some purposes, gray iron castings can also be heat treated, such as to relieve residual stresses, improve machinability, increase the hardness of the surface either through induction or flame hardening, or harden the entire section through an oil quench and draw treatment. Such heat treatment will not change the graphite structure. Although the graphite may increase in volume if a pearlitic iron is completely ferritized, in which case, the graphite is usually deposited on the flakes originally present. The matrix however is quite responsive to heat treatment just as in the case of steel.
Machining Capability of Grey Iron Castings
Grey iron supply a hardness level that is machinable. With machining facilities in house, we can do machining also after casting. Once our customers have machining requirement on grey iron castings, it will be best to supply us both casting and finished drawings. Our engineering team will strictly machine products referring to the machining drawings. Our machining capability can greatly reduce additional cost for our customers.
Grey iron casting is used in many market segments, including automotive, agricultural, machinery building, electronics, irrigation, ventilation, architecture, construction and transportation industries.
The typical finished Gray iron casting products.
Grey iron castings are frequently used to make: valves, cases, engine blocks, dies, pump housings, pipes, brake drums, decorative embellishments and grey cast iron cookware.
Benefits of Grey Iron Castings
There are a number of important benefits that the use of Gray Iron for casting provides. Gray Iron Castings can be:
|High carbon content for melting, weld, machine easily.|
|Low shrinking during the casting process.|
|High conductivity, ideal for cookware.|
|Machined more easily|
|Used in applications that require high strength to weight ratios|
|Produced economically in high volumes using disamatic equipment|
Gray iron casting Applications
Gray iron casting is used in many market segments, including automotive, agricultural, machinery building, electronics, irrigation, ventilation, architecture, construction and transportation industries.
Gray iron castings are the optimal choice for the construction of highly durable and strong products.
As per its grade or class:
|Class 300 Gray Iron||For the production of beds, gears, cylinder blocks, heavy-duty machine tools, high-pressure hydraulic components, cylinder heads, bushings, piston rings etc.|
|Class 200 and Class 250||For manufacturing cylinder bases and liners, brake wheel, gearboxes, coupling plate, flywheel and pressure valves.|
|Class 100 and Class 150||For creating hammers, pipes, pulleys, protective covers, hand wheels, bearings and pumps.|
Gray iron castings the most widely used type of cast iron.China foundry is the best choice for parts from Gray iron casting. If you have any inquiry of it,kindly contact us freely.
Variations and Similar Processes
Different grey iron casting processes include centrifugal casting, die casting, sand casting and ductile iron casting.
Centrifugal casting is a method used to cast cylindrical parts and components that produces fine-grained outer surfaces with even dispersion. To work, liquefied grey iron is poured into a mold that rotates at high speeds as it is introduced. Centrifugal casting stands apart from many other types of casting because it is mainly used to create stock materials for further machining, as opposed to parts shaped for specific applications. Grey iron castings made via this process can also be almost any diameter, length, and thickness.
Die casting is popular for continuous cycle or the fast production of castings. It uses reusable molds that are made in the shape of the desired finished product. To die cast the metal, manufacturers must inject it into the die and apply pressure. Die casting is good for use with small to medium parts that require good dimensional stability, carefully produced details and good surface quality.
Sand casting, or sand molding, is a low-cost and low-maintenance casting option that uses a sandy mixture as a mold. The four main mixtures from which manufacturers may choose are called no bake, dry sand, skin-dried, and green sand.
• No bake molds are disposable molds, made of sand, a quick-setting resin, and a catalyst. They are formed with the help of a casting flask, which is usually made out of plastic, wood or metal. No bake molds employ a heat-free, cold-setting casting process.
• During dry sand molding, unbonded sand is mixed with an adhesive or a chemical binder, shaped to form a mold and then baked a certain temperature to finish. To make castings, molten grey iron is poured into the mold, taking its shape.
• To create a mold using the skin-dried molding method, also known as air-dried molding, operators mix water, sand, a binder like clay and bonding additives and then dry it with a torch or heating lamp.
• Green sand molds are made the same way, minus the bonding additives and the heat drying.
Ductile iron casting, also known as spheroidal graphite casting, SG iron casting or nodular iron casting, was developed in 1943 by Keith Mills. This process involves melting and casting ductile iron (iron alloys with controlled microstructures) along with one of the elements that makes it ductile. This is usually either magnesium, cerium or yttrium. Ductile iron castings are not only more ductile than grey iron castings, but also have higher tensile strength than gray iron castings. Because of the high tensile strength and ductility it produces, ductile iron casting is used to produce: water pipes, sewer pipes and components of: windmills, tractors, trucks and cars, piano harps and oil rigs.