4140 Heat Treated Steel Plate | Precision Grinding, Inc.

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Heat Treated 4140 Steel Plate

  • 4140 PH or 4140 PREHARD has the same industry standard chemistry as Heat Treated 1045 Plate
  • 4140 Steel Bar
  • 4140 HR Steel Plate
  • 4140 Flat Bar
  • Oil Quenched & Tempered


Standard Hardness

4140 PH has a standard, industry recognized Rockwell C Hardness rating of 28 – 32. Most sources recognize and tend to prefer quoting and requesting the Rockwell C Scale. 4140PH ranges from Brinell Hardness 270 – 300. Thick 4140 AN (in the annealed condition) is flame cut, then annealed onsite in our furnace.

Annealing greatly improves grinding and machining. Parts can be returned to the standard hardness when followed by a normalize & specific tempering heat treatment process.

Services for Heat Treated 4140 Steel Plate


Typical Applications

  • Tooling, machine plates, gears, shafts, sprockets, Special Machine Parts
  • Molds, Metal Stamping, Tool & Die, Shredders
  • Automotive, Oil & Gas Industries, Machine Shop, Paper Mills


Hardening Properties

Purchased as Normal HR (hot-roll), Pre-Hardened PH, or in the AN Annealed condition, this chromium molybdenum alloy steel possesses a full range of hardening and wear resistance properties. Combinations of Flame hardening, induction hardening, or oil hardening can considerably increase the wear resistance of the finished ground and machined parts.  Quenching, Normalizing & tempering processes can increase the hardness to the desired level.

4140 Annealing & Stress Relieving

With proper furnace heating techniques, AISI 4140 maintains its properties through exposure to the relatively high heating temperatures during annealing or stress relieving. With an on-site 8′ x 8′ x 14′ car-bottom furnace, Precision Grinding anneals parts cut from 4140 every week. We operate the oven every day of the week, M-F, and heat records are stored for every batch of parts that enter our oven.


Welding Properties AISI 4140 Steel can be welded, providing the section is preheated during welding, then stress relieved after welding.

Types of Machined Steel Plate Shapes Manufactured from Plate and Flat Bar

Base plates, machine bases, die plates, die shoes, gears, steel molds, platens, sprockets, liners & wear plates


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