Ferrous alloys are iron based alloys which have found extensive usage in wide range of industries because of its flexibility to meet strength, toughness, and impact of diverse industrial applications. This flexibility depends on the heat treatment processes and methods, which modifies the final micro-structure. Examples of ferrous alloys include carbon steels, stainless steels, alloy steels, tool steels, cast steel, cast iron, maraging steel, and specialty or proprietary iron-based alloys.
These days, many alloy manufacturers are trying to meet the compositional standards of the Unified Numbering System (UNS). Unified Numbering System (UNS), jointly developed by American Society for Testing and Materials (ASTM) and the Society of Automotive Engineers (SAE), offers an overall designation system for thousands of metals and alloys in commercial use.
In UNS, metals and alloys are assigned a lettered prefix followed by a five-digit number. For example, carbon steels and alloy steels are categorized under the UNS G category and carry designations, such as UNS G10950.
Other Specifications for Ferrous Metals and Alloys
· AISI-SAE
· European Norm (EN)
· Casting grades
· U.S. Military specifications (MIL-SPEC)
Types of Ferrous Alloys
There are different types of ferrous alloys available in the market, which include – carbon steels, alloy steel, stainless steel, cast iron, cast steel alloy grades, cast iron alloy and iron alloy. Brief descriptions of these ferrous alloys are given below:
· Carbon steels are ferrous alloys which contain carbon and small levels of other alloying elements, such as manganese or aluminum.
· Alloy steels contain low to high levels of elements such as chromium, molybdenum, vanadium and nickel.
· Stainless steels are highly corrosion resistant, ferrous alloys which contain chromium and/or nickel additions.
· Cast iron, a ferrous alloy, contains high amounts of carbon. Ductile iron, gray iron and white cast iron grades are different cast iron types.
· Cast steel alloy grades are made by pouring molten iron into a mold.
· Cast Iron Alloy and Iron Alloy are 2 major ferrous alloys used in most industrial applications.
Material suppliers provide ferrous metals and alloys in many shapes and forms:
· Semi-finished stock shapes are used for part fabrication. They are also suitable as feedstock for casting, forging, spinning and other forming processes.
· Common stock shapes include bars, rods, tubes, plates, strips, shims, spheres, foil, wire, billets, slabs, and blooms.
· Materials are also available as ingots, powders, fillers, and reinforcements.
Ferrous Alloys Casting
Companies often specialize in casting of ferrous alloys due to the requirement of specialized equipment for melting and pouring ferrous materials. Casting of ferrous materials is typically achieved through means of shell casting, sand casting, or to a lesser extent investment casting.
In ferrous casting, the most commonly used metal materials are cast iron alloys and iron alloys that include grey iron casting, ductile iron casting and steel iron casting.
Buying Tips
Before choosing ferrous metals and alloys for specific usages, a buyer must analyze the followings:
· Dimensions: Outer diameter (OD), inner diameter (ID) overall length, and overall thickness are important dimensions.
· Production processes: Most materials are cast, wrought, extruded, forged, cold-finished, hot-rolled, or formed by compacting powdered metals or alloys. Electric arc furnaces are used to produce very clean metals and alloys with fewer inclusions and lower variability.
· Features: For improved weldability and the corrosion resistance Low carbon steels are used. For compressive strength, cold-worked steels are suitable.
