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Written by G.L. Huyett Marketing Department on 10/14/2020 with 0 comments

Carbon and Alloy Steels: Part Two

Common Grades of Steels and Alloys

The following information should be considered only as a basic guideline; the data should not be considered as absolute. For specific applications, proper testing is required. The hardness of a metal is determined by its resistance to deformation, indentation, or scratching. Rockwell hardness is the most common measure of a metal's hardness. Soft steels are usually measured using the Rockwell B scale while harder steels and deep case hardened steels are usually measured on the Rockwell C scale. In some cases, one object may fall within more than one scale. For example, a typical steel spring has a Rockwell hardness of 110 on the B scale and 38 on the C scale. In addition, several factors, including the size of the piece, can affect the hardness rating.

Yield strength is the amount of pressure a material will accept before becoming permanently deformed.

1018 Steel


Heat treating in contact with carbon (carburizing) hardens the surface of this low‑carbon steel. It is easy to cold‑form, bend, braze, and weld. Rockwell hardness is B71. Melting point is 2800°F. Yield strength is 53,700 psi. It is commonly used in shafts, spindles, pins, rods, sprockets, and component parts such as clevis pins, straight pins, machine keys, and keystock.

1045 Steel


This medium‑carbon steel is stronger than 1018 and is slightly more difficult to machine and weld. Rockwell hardness is B84. Melting point is 2800°F. Yield strength is 45,000 psi. It is used in gears, shafts, axles, bolts, studs, clevis pins, machine keys, and keystock.

A36 Steel


General purpose carbon steel is suitable for welding and mechanical fastening. Rockwell hardness is B68. Melting point is 2000°F. Yield strength is 36,000 psi. This is used primarily for structural and commercial grade steel.

12L14 Steel


A low‑carbon steel that has excellent machining characteristics and good ductility that makes it easy to bend, crimp, and rivet. It is very difficult to weld and cannot be case hardened. Rockwell hardness is B75‑B90. Melting point is 2800°F. Yield strength is 60,000‑80,000 psi. This grade can be used for grease fittings, clevis pins, and custom pins.

1144 Steel


A medium‑carbon, resulferized steel with free‑machining qualities. 1144 steel heat treats better than 1045 steel. Stress relieving allows it to obtain maximum ductility with minimum warping. Rockwell hardness is B97. Melting point is 2750°F. Yield strength is 95,000 psi. This is frequently used in keyed shafts, clevis pins, and detent pins.

4140 Alloy

4140 Alloy

Also called "chrome‑moly" steel. Ideal for forging and heat treating, 4140 alloy is tough, ductile, and wear resistant. Rockwell hardness is B92. Melting point is 2750°F. Yield strength is 60,000‑75,800 psi. It is the most common steel and is used in virtually all industries and applications. It is also used for clutch keys, clevis pins, and military clevis pins.

4140 ASTM-A193 Grade B7 Alloy

4140 ASTM‑A193 Grade B7 Alloy

Similar to 4140 alloy, but it is already quenched, tempered, and stress relieved. Maximum Rockwell hardness is C35. It is commonly used for threaded rod.

8630 Alloy

8630 Alloy

This alloy is tough yet ductile. It responds well to heat treating, exhibits superb core characteristics, and has good weldability and machining properties. Maximum attainable Rockwell hardness is C15. Melting point is 2800°F. Yield strength is 79,800 psi. This grade is frequently used in machine keys, woodruff keys, gear drive keys, and keystock.

If you missed the first part of this series on carbon and alloy steels, click HERE to catch up.

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