• Alloy Steel Bar

Through-Hardening Alloy Steel
Standard A434M, BS 970, AS1444 or equivalent.
Size Range (mm) 16 to 500 (diameter).
Grades 4140, 4340, En25, En26 & Hytuf.
Finishes As Rolled or Turned.
Condition Refer below.
Processing (mm) Bar cutting to 650 diameter.
Case-Hardening Alloy Steel
Standard A434M, BS 970, AS1444 or equivalent.
Size Range (mm) 16 to 500 (diameter).
Grades 8620, En36A & En39B.
Finishes As Rolled or Turned.
Condition Refer below.
Processing (mm) Bar cutting to 650 diameter.

Alloy steel bar is available through Atlas Steels by indent or special stocking arrangement with end user customers.

Atlas Steels locations and contacts can be found in the main menu of this website

Condition of steel

High Tensile Strength Steels
For applications requiring higher tensile strengths and toughness than the carbon steels there is a range of low alloy steels. These are categorised as high tensile or constructional steels and case hardening steels. The high tensile strength steels have sufficient alloying additions enabling through hardening (by quench and temper treatment) according to their alloying additions.

Case Hardening (carburising) Steels
Case hardening steels are a group of low carbon steels in which a high hardness surface zone (hence the term case hardened) is developed during heat treatment by absorption and diffusion of carbon. The high hardness zone is supported by the unaffected underlying core zone, which is lower hardness and higher toughness.

Plain carbon steels that can be used for case hardening are restricted. Where plain carbon steels are used, the rapid quenching necessary to develop satisfactory hardness within the case can cause distortion and the strength that can be developed in the core is very limited. Alloy case hardening steels allow the flexibility of slower quenching methods to minimise distortion and high core strengths can be developed.

Nitriding Steels
Nitriding steels can have higher surface hardness developed by absorption of nitrogen, when exposed to a nitriding atmosphere at temperatures in the range of 510-530°C, after hardening and tempering.

High tensile steels suitable for nitriding are: 4130, 4140, X4150 & 4340.

Grade Data Sheets

Grade Description and Typical Application
4140
Data Sheet
General purpose high tensile Cr-Mo low alloy steel, widely used for axles, shafts, studs and bolts, gears and drill rods.  The steel is usually supplied pre-hardened, but can be flame or induction surface hardened or nitrided.
4340
Data Sheet
General purpose high tensile Ni-Cr-Mo low alloy steel with higher strength and able to be hardended through larger sections compared to 4140.  Used in highly stressed shafts in larger sizes, heavy truck and tractor axles and transmission shafts.  Supplied pre-hardened but with further re-hardening or surface hardening possible.
En25 En25 is used extensively in most industry sectors for applications requiring higher tensile and yield strength than 4140 can provide, similar to En26 but with lower carbon content.
En26 Characterised by high strength and toughness in very large sections, similar to En25 but with a higher carbon content. En26 is used extensively in most industry sectors for applications requiring higher tensile strength and yield strength than 4140, 4340 or En25 can provide.
Case Hardening
8620H
Data Sheet
General-purpose case hardening steel suitable for comparatively lightly stressed components. Used for automatic components such as transmission gears, crown wheels, ring gears, hypoid gears and racers, king pins and pinions.
6587
Data Sheet
The high chromium content produces high case hardness with excellent core strength. Used for gears, bearings, sleeves, pins, bushes, shafts, plastic moulds and any highly stressed or high wear component.
En36A Used extensively for highly stressed gears in trucks, agriculture and mining machinery, pins and brushes, heavily loaded shafts and other applications requiring a hard surface with a tough shock-resisting core. Core tensile 55tsi minimum after hardening and tempering.
En39B An exceptionally high hardenability steel for large or highly stressed gears where core strength and toughness are required. May be used as an alloy engineering steel. Core tensile strength 85tsi minimum after hardening and strengthening.

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