Ferrous alloys are iron based alloys that has extensive use 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 procedures, which modifies the final micro-structure. Examples of ferrous alloys include carbon steels, alloy steels, stainless steels, tool steels, cast iron, cast steel, maraging steel, and specialty or proprietary iron-based alloys.
Now-a-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), provides 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 instance, 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
- Casting grades
- European Norm (EN)
- U.S. Military specifications (MIL-SPEC)
Types of Ferrous Alloys
Various types of ferrous metals and alloys are available in the market:
- Carbon steels are ferrous alloys that 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 that 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 types of cast iron.
- Cast steel alloy grades are made by pouring molten iron into a mold.
- Cast Iron Alloy and Iron Alloy are two major ferrous alloys used in most industrial applications.
The following are ferrous metals and the kind of uses to which they are usually put:
- Mild Steel – Carbon content of 0.1 to 0.3% and Iron content of 99.7 – 99.9%. Used for engineering purposes and in general, none specialised metal products.
- Carbon steel – Carbon content of 0.6 to 1.4% and Iron content of 98.6 to 99.4 %. Used to make cutting tools such as drill bits.
- Stainless Steel – Made up of Iron, nickel and chromium. Resists staining and corrosion and is therefore used for the likes of cutlery and surgical instrumentation. See our infographic celebrating 100 years of stainless steel usage in buildings or the different types of stainless steel.
- Cast Iron – carbon 2 – 6% and Iron at 94 to 98%. Very strong but brittle. Used to manufacture items such as engine blocks and manhole covers.
- Wrought Iron – Composed of almost 100% iron. Used to make items such as ornamental gates and fencing. Has fallen out of use somewhat.