Machinery grade steels

Machinery grade steels are generally very versatile low-alloy steels, used for the manufacture or repair of machinery in general. They contain one or more alloying elements such as Nickel (Ni), Chromium (Cr), Molybdenum (Mo), among others, which are intentionally added to the iron-carbon base (Fe-C).

Among machinery grade steels, the most common for the industry is 4140 steel, which is used for the manufacture of mechanical parts or devices such as gears, cams, worm screws, high resistance screws, crowns, bolts, etc.

• In pre-tempered condition (treated or tempered), it has a good combination of toughness and resistance that allows its direct use in machinery parts applications.
• In its pre-tempered (treated) condition, it can be nitrided or its hardness increased by flame or induction hardening.
• It can be welded; however, certain precautions must be taken to reduce the risk of fracture.

Other machinery grade steels

In addition to the common use of 4140 steel, there are alloys such as 9840, which is a low-alloy steel of the Cr – Ni – Mo type for mechanical applications (arrows, crown gears, etc.); Its hardenability is higher than 4140 steel (uniformity of hardness from the surface to the core), and with better resistance to mechanical fatigue.

Like medium carbon steels, precautions must be taken if it will be subjected to welding processes.

In annealed condition it can be subjected to hardening by quenching and tempering to hardness values ​​around (~ 50 HRC).

On the other hand, 8620 steel used in applications with high wear resistance on the surface and toughness in the core. The main characteristic of 8620 steel is that it is tenacious at its core, helping the manufactured parts not to fracture. Annealed to an estimated hardness ~ 150 HBN (~ 80 HRB) as cold drawn.

Its main applications are intended for those where it is necessary to confer high hardness on the surface and counteract the wear caused by dynamic metal-metal contact.

Applications of Machinery Grade Steels 

• Gears
• Crowns
• Pinions
• Automotive components
• Arrows
• Camshafts

In the case of annealed 4140, it has an estimated hardness of ~ 190 HB (~ 91 HRB), it is a steel with which we manufacture our part, and subsequently we subject it to a heat treatment (quenching and tempering) with the purpose of raising its hardness (~50 – 52 HRC max.).

In its treated condition, it is a steel that we market with an average hardness between ~ 248 – 301 HB (~ 24 – 32 HRC); With this presentation, the required part is manufactured and put to work without the need to undergo additional heat treatment.

At Serviacero Especiales we handle 4140R, 4140T, 9840T, 8620 and 8620H.

To learn more about machinery grade steels, come to us, we have a team that can respond to your requests, we have additional technical information that will undoubtedly help improve your processes where the main application is machinery grade steels.

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