Metal Casting Details

Cast Iron Castings
Cast Iron is essentially an alloy of iron, carbon (2-4%) and silicon in which the carbon is present in excess of the amount which can be retained in solid solution in austenite at the eutectic temperature. When cast iron contains a specially added element or elements in amounts sufficient to produce a measurable modification of the physical properties of the section under consideration, it is called alloy cast iron. Silicon, manganese, sulphur, and phosphorus, as normally obtained from raw materials, are not considered alloy addition.

Ductile Iron Castings
Since ductile iron was developed in the 1940s, this remarkable metal has proved its value in tens of thousands of engineering and casting applications. Ductile iron is created by an alloying process which converts the crack-promoting graphite flakes of gray iron into nodules. With this microstructural transformation, the metal acquires superior ductility, elongation characteristics, and machinability. The ductile iron family offers the design engineer a unique combination of strength, wear resistance, fatigue resistance, and toughness, as well as excellent ductility characteristics. In all its grades, ductile iron exhibits mechanical properties that make it an ideal alloy for investment casting.

Ni Hard Castings
The oldest group of high-alloy irons of industrial importance, the nickel-chromium white irons (or "Ni-Hard" irons), has been produced for more than 50 years and is a very cost-effective material for crushing and grinding.

Ni-Hard is a metal with chrome content of 1.4% to 28%. It is an abrasive iron for low and high stress abrasion in mining, milling, and earth handling uses. It is also used extensively in the power plant industry, brick plant industry, asphalt industry, cement industry, and rock crushing industry.

The optimum composition of a nickel-chromium white iron alloy depends on the properties required for the service conditions, and the dimensions and weight of the casting being produced.  Ni - Hard casting is an extremely wear resistant material, and in cast form is ideal for use with abrasive products, giving a much more extended life when compared with regular cast iron or mild steel. 

Carbon Steel Castings
Cast, low carbon steels contain only carbon as the principal alloying element. Other elements are present in small quantities, including those added for de-oxidation.  Silicon and manganese are present in cast carbon steels - typically ranging from 0.25 to about 0.80% Si, and 0.50 to about 1.00% Mn.  Carbon steels can be classified according to their carbon content into three broad groups:

• Low-carbon steels contain less than 0.20% Carbon
• Medium-carbon steels contain 0.20 to 0.50% Carbon
• High-carbon steels contain greater than 0.50% Carbon

Carbon steel castings are produced to a great variety of properties because composition and heat treatment can be selected to achieve specific combinations of properties, including hardness, strength, ductility, fatigue resistance, and toughness.

In addition to Cast Steel Castings, Carbon Steel produced in steel mills is one of the most widely used materials for building the world's infrastructure and industries; it is used to fabricate everything from pins to oil tankers. The main reasons for the popularity of steel are the relatively low cost of making, forming, and processing it - the abundance of its two raw materials (iron ore and scrap) - and its unparalleled range of mechanical properties. 

The three major steel making processes are - basic oxygen, open hearth, and electric arc. The first two processes, with few exceptions, use liquid blast-furnace iron and scrap as raw material, while the latter uses a solid charge of scrap and dri (direct reduced iron). The products of the steel making process are continuous cast section ready for hot rolling and cast billets for further processing.

Stainless Steel Castings
A wide range of steels containing chromium and nickel, exhibiting high resistance to corrosion.  Stainless steel differs from carbon steel by the amount of chromium present. Carbon steel rusts when exposed to air and moisture. This iron oxide film (the rust) is active and accelerates corrosion by forming more iron oxide. Stainless steels have sufficient amounts of chromium present so that a passive film of chromium oxide forms which prevents further surface corrosion and blocks corrosion from spreading into the metal's internal structure.
In metallurgy, stainless steel, also known as inox steel or inox, is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass. Stainless steel does not stain, corrode, or rust as easily as ordinary steel (it stains less, but it is not stain-proof). It is also called corrosion-resistant steel or CRES when the alloy type and grade are not detailed, particularly in the aviation industry. There are different grades and surface finishes of stainless steel to suit the environment to which the material will be subjected in its lifetime. Common uses of stainless steel are cutlery and watch cases and bands.  The corrosion resistance of iron-chromium alloys was first recognized in 1821 by the French metallurgist Pierre Berthier, who noted their resistance against attack by some acids and suggested their use in cutlery. Metallurgists of the 19th century, however, were unable to produce the combination of low carbon and high chromium found in most modern stainless steels, and the high-chromium alloys they could produce were too brittle to be practical.

Manganese Castings (HADFIELD'S STEEL, MANGALLOY)
A work hardening cast steel containing 12 to 14% manganese.  Mangalloy is made by alloying steel, containing 0.8 to 1.25% carbon, with 11 to 15% manganese. Mangalloy is unique non-magnetic steel with extreme anti-wear properties. The material is very resistant to abrasion and will achieve up three times its surface hardness during conditions of impact, without any increase in brittleness which is usually associated with hardness. This allows mangalloy to retain its toughness.
Most steels contain 0.15 to 0.8% manganese. High strength alloys often contain 1 to 1.8% manganese. At about 1.5% manganese content, the steel becomes brittle, and this trait increases until about 4 to 5% manganese content is reached. At this point, the steel will pulverize at the strike of a hammer. Further increase in the manganese content will increase both hardness and ductility. At around 10% manganese content the steel will remain in its austenite form at room temperature. Both hardness and ductility reach their highest points around 12%, depending on other alloying agents.
Mangalloy has been used in the mining industry, cement mixers, rock crushers, and other high impact and abrasive environments. These alloys are finding new uses as cryogenic steels, due to their high strength at very low temperatures. Mangalloy is heat treatable, but the manganese lowers the temperature at which austenite transforms into ferrite. Most grades are ready for use after annealing and then quenching from a yellow heat, with no further need of tempering, and usually have a normal Brinell hardness of around 200 HB, (roughly the same as 304 stainless steel), but, due to its unique properties, this number has very little effect on determining the abrasion and impact resistance of the metal.
Many of mangalloy's uses are often limited by its difficulty in machining. The metal cannot be softened by annealing, and usually requires special tooling to machine. The material can be drilled with extreme difficulty using diamond or carbide. Although it can be forged from a yellow heat, it may crumble if hammered when white-hot, and is much tougher than carbon steel when heated. It can be cut with an oxy-acetylene torch, but plasma or laser cutting is the preferred method. Despite its extreme hardness and tensile strength, the material may not always be rigid. It can be formed by cold rolling or cold bending.

Aluminum Castings
Aluminum a silvery-white, ductile metallic element the most abundant metal in nature, a metallic element of 2.7 sp gr atomic wgt 26.97, atomic number 13, mp 1220 F (660 C). Extensively used for castings, foundry patterns and core driers and as a deoxidizer in iron and steel making.

Zinc Castings
Predominant alloying element in brass, a metallic element with mp of 419 C (786.2F); used extensively in die castings and as a corrosion-resistant coating for ferrous alloys.

Meehanite Castings
Meehanite Metal castings cover any casting within the overall cast iron composition range that have been produced by the Meehanite process. This process involves a number of patented procedures seeking to control and produce the desired graphite distribution and the desired matrix structure in the casting. It depends primarily on the establishment of a melt of desired degree of under-cooling often referred to as constitution and the controlled nucleation of this melt, usually by means of alkaline earth silicide additions. It requires very careful selection of raw materials, meticulous process controls and a very thorough knowledge of the foundry behavior of cast iron. The Meehanite process involves the use of standard procedures in all phases of casting manufacture including gating and risering techniques, sand control testing methods and many specialized molding procedures. It seeks to eliminate guesswork, thereby resulting in an engineering product of high integrity and reliability.

Bronze Castings
Copper-base alloys, with tin as the major alloying element; further defined in relation to second major alloy element, as silicon bronze, aluminum bronze.

Brass Castings
Copper base alloys with zinc as the major alloying element.

Tool Steel Castings
Any high-carbon or alloy steel used to make a cutting tool for machining metals and for metalcasting dies.