Alloy Steel
Alloy Steel Forged Parts
Alloy steels are generally considered to be steels to which one or more alloying elements are added to improve certain properties that cannot be obtained in carbon steels. Such steels are found in the AISI 1300 through AISI 9800 series. A steel is considered to be an alloy steel when the amounts of manganese, silicon, and copper exceed the maximum limits for carbon steel, or when minimum amounts of alloying elements such as chromium, molybdenum, nickel, titanium, columbium, and vanadium are specified. The alloying elements of the steel improve its performance in its in-service end use. Alloy Steel 4140 is the most commonly used material for open die forging or the manufacture of seamless rolled rings.
As with carbon steels, forging improves the impact strength, ductility, fatigue strength, and toughness, by breaking up segregation, consolidating porosity, and helping internal homogenization. It produces a fibrous grain structure, which improves mechanical properties parallel to the grain flow. It also reduces grain size.
Common alloy steels include:
4140, 4130, 4330V, 4340, E4340, 42CoMo4, 21CrMoV511, 18CoNiMo7-6, A350 LF2, and 8620
Alloying elements such as nickel, chromium, molybdenum and other elements may be added to steel for several significant reasons. The first is the improvement in mechanical properties, such as strength, ductility and toughness, due to the increased hardenability that comes from the alloy additions. Then there is the improvement in mechanical properties at elevated or low (sub-zero) temperatures. Alloying elements can increase resistance to corrosion and to elevated temperature oxidation. In addition, elements improve wear resistance.
- Strength: Alloying elements like chromium and molybdenum increase tensile strength
- Hardness: Elements like carbon and vanadium increase hardness
- Toughness: Elements like nickel and manganese increase toughness
- Corrosion resistance: Elements like chromium and silicon increase resistance to rust and corrosion
- Heat resistance: Elements like molybdenum and tungsten increase the ability to retain strength at high temperatures
Alloy steel can be annealed, normalized, normalized and tempered, or normalized, quenched and tempered. Hardness can range from 163 BHN to as high as 402 BHN depending upon the Class (in the specification), heat treatment, and part size. Industry standard specifications include AISI, ASTM, AMS, SAE, API, UNS and international standards depending upon the chemistry, mechanical properties, and shape of the alloy steel part for its end use.
Alloy steels are widely used in the manufacture of open die forging and seamless rolled rings. The alloy additions and the metallurgical changes brought about by these two processes ensure the production of parts that will meet all stipulated specifications, plus the requirements of the end use as provided by the customer. When the end use is known, All Metals & Forge Group can work with its customers to meet the requirements of the part in-service.
All Metals & Forge Group has much experience in the forging, heat treatment, and testing of alloy steels in the production of open die forgings and seamless rolled rings. We also stress the importance of very close cooperation with our customers in meeting all parameters necessary to meet their production schedules, and their customers’ end use in-service requirements.
All Metals & Forge Group takes great pride in maintaining one of the most stringent ISO9001, AS9100 quality systems in the open die forging and seamless rolled ring industry. It begins with taking a customer’s end use, required forged surface condition, mechanical properties of the specified alloy, forged shape, heat treatment, delivery need, and competitive price. All this is coupled with forging soundness proven by ultrasonic testing, and care in packing goods to arrive in pristine condition at the customer’s desired location. Every step is monitored by the quality system at AMFG and continuously improved.
AMFG performs rough machining to within 3mm of finished dimensions to reduce the CNC cost at the customer’s machine shop for all the forged shapes the company produces. The rough machined surface condition is 250 RMS so that proper quality testing can be performed on each part – the AMFG standard.
AMFG can perform finish machining to within .001 of an inch for final tolerance and 64 or 32 RMS surface finish. This level of quality and precision is unique in an industry where other suppliers’ parts are often delivered black, as forged, or with a rough machined surface of 500 RMS, without the internal or external steps and dimensions to reduce machining costs.
From inquiry to invoice, All Metals & Forge Group quality is managed and not assumed. Whether the need is for one part, an entire project, or a production run, AMFG delivers.

All Metals & Forge Group takes great pride in maintaining one of the most stringent ISO9001, AS9100 quality systems in the open die forging and seamless rolled ring industry. It begins with learning the customer’s end use, required forging surface condition, mechanical properties of the specified material and alloy, forged shape, heat treatment, delivery need, and competitive price, coupled with forging soundness proven by ultrasonic testing, and care in packing goods to arrive in pristine condition at the customer’s desired location. Every step is monitored by the quality system at AMFG and continuously improved.
AMFG performs rough machining to within 3mm of finish dimensions to reduce the CNC cost at the customer’s machine shop for all the forged shapes the company produces. The rough machine surface condition is 250 RMS so that proper quality testing can be performed on each part – the AMFG standard.
The company can perform finish machining to within .001 of an inch for final tolerance and 64 or 32 RMS surface finish. This level of quality and precision is unique in an industry where other company’s parts are often delivered black, as forged, or with a rough machined surface of 500 RMS without the internal or external steps and dimensions to reduce machining costs.
From inquiry to invoice, All Metals & Forge Group quality is managed and not assumed. Whether the need is for one part, an entire project, or a production run, AMFG delivers.
U.S. 1 (973) 276-5000 • 1 (800) 600-9290 • Canada 1 (416) 363-2244
Fax: 1 (973) 276-5050 • Sales@Steelforge.com
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In the U.S. 1 (973) 276-5000 / 1 (800) 600-9290.
In Canada 1 (416) 363-2244.
Email us at sales@steelforge.com.