September 26, 2018

52100 Steel (100Cr6)

52100 is a high-carbon chromium alloy steel, which, because of its versatility, is used in a variety of mechanical applications. In the annealed condition this steel is comparatively easy to machine, yet very high hardness and abrasion resistance can be developed by heat treatment to make the steel particularly suitable for applications requiring extreme wear resistance. In addition, 52100 alloy steel can be heat treated to high levels of tensile strength and fatigue strength.

FOR REQUIREMENTS: Standard Bearing Steel
ASTM A485 (for modified grades)

Benefits of 52100

  • Tubing material made in Electric Furnaces with refining techniques to ensure maximum cleanliness and freedom from microscopic inclusions
  • Material meets ASTM A295 and AMS 6440; Modified Grades meet ASTM A485
  • Two modifications have also been developed with increased hardenability; suitable for applications requiring high hardness from thin to heavy sections

Typical Applications

  • Anti-Friction Bearings & Rollers
  • Slitting Rolls, Spacers and Knives
  • Knife Blades and Cutlery
  • Seals, Sleeves & Bushings
  • Tools, Dies & Molds
  • Engine & Hydraulic Parts

Comparison to Other Materials

Tool Steels – Compared with tool steels in general, 52100 is less expensive and is much easier to handle. It is easier to form and machine than most tool steels yet can, after simple heat treatment, develop many of the properties of tool steels.

Carburizing Grades – Compared with the carburizing grades of alloy steels, 52100 sacrifices some machinability but in return the user has a material with a much more simple and inexpensive heat treatment that minimizes distortion.


52100 alloy steel tubing is generally furnished in the spheroidized annealed condition with maximum Brinell Hardness Number 207 for hot-finished or turned tubing, and 248 for cold-drawn tubing; roto-rocked tubing may exhibit a Brinell Hardness up to 331. As furnished, each finish is in a condition for optimum machinability for its type, and for maximum uniformity after heat treatment. The long spheroidizing anneal may decarburize the exposed OD and ID tube surfaces to depths controlled by ASTM A295. This shallow decarburized surface must be removed in machining.

52100 is recommended for through hardening by oil quenching in sections up to 0.5 inch. For sections over 0.5 inch it may be necessary to water-quench for full hardness. In order to eliminate the necessity of water-quenching and subsequent danger of distortion or cracking, two modifications have been developed for oil quenching, ASTM A485-Grade 1, which is recommended for sections 0.500 to 0.750 inch, and ASTM A485-Grade 3 for sections from 0.750 to 1.500 inch.

52100 VAR


52100 VAR steel is a deep hardening alloy steel used for aircraft bearings and other high stressed parts where good rolling contact fatigue strength is required.

This grade is produced by the vacuum-arc remelting (VAR) process and offers greatly improved cleanliness and internal soundness over conventionally air melted bearing quality SAE 52100 steel.

FOR REQUIREMENTS: Aircraft Bearing Steel


  • Aircraft Bearings such as flight control (flap & slat) applications where fatigue life is critical.

Chemical Composition

  52100 ASTM A485-Grade1 ASTM A485-Grade3
Carbon 0.93 – 1.05 0.90 – 1.05 0.95 – 1.10
Manganese 0.25 – 0.45 0.90 – 1.20 0.65 – 0.90
Phosphorus 0.025 max
0.015 max (52100 VAR)
0.025 max 0.025 max
Sulfur 0.015 max 0.015 max 0.015 max
Silicon 0.15 – 0.35 0.45 – 0.75 0.15 – 0.35
Chromium 1.35 – 1.60 0.90 – 1.20 1.10 – 1.50
Copper 0.30 max 0.30 max 0.30 max
Nickel 0.25 max 0.25 max 0.25 max
Molybdenum 0.10 max 0.10 max 0.20-0.30
Aluminum 0.05 max 0.05 max 0.05 max

Stocking Sizes

  Type OD
52100 Tube OD Ranges Cold Drawn or Roto-rocked 0.777″ – 2.708″
Hot Rolled 1.932″ – 12.143″
52100 Bar Diameter Ranges Cold Drawn 0.130″ – 2.750″
Rough Turned 1.000″ – 2.875″
Hot Rolled 2.559″ – 12.143″
Forged & Turned 10.000″ – 15.50″
VAR 0.236″ – 6.000″
52100 Wire AMS 6440 Can be drawn to custom size wire or bar 0.216” – 0.413”



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