4140/42 PH

*Always consult your Heat Treater*
     *Information Provided is General*

4140/42PH is a widely used quenched and tempered medium carbon alloy steel. 4140/42PH is an oil-hardening steel of relatively high harden ability. The chromium content provides good hardness penetration, and the molybdenum imparts uniformity of hardness and high strength. The grade is especially suitable for forging because they have self-scaling characteristics, respond readily to heat treatment and are comparatively easy to machine in the heat-treated condition. 4140/42PH maintains their properties even after long exposure at relatively high working temperatures. With a combination of such highly desirable properties as good strength and wear resistance, excellent toughness coupled good ductility, and the ability to resist street at elevated temperatures, it is understandable why these are widely used and highly successful alloy steels.

This pre-hardened steel has a hardness of Brinell 262-311, 26-32 RC. 4140/42PH is excellent for tooling and maintenance applications and numerous machine component parts. The countless applications include backup and support tooling, die details, short run dies, arbors, spindles, brake dies, axles, bolts, forming rolls and other machine tool components. This heat-treated medium carbon alloy has every requisite for all around good service in applications requiring wear resistance toughness, high mechanical properties and good machinability.

4140/42PH has 0.02 more carbon than 4140ANN.

The 4140/42PH stock is pre-heat treated versus the 4140ANN, which is annealed.

Hardening happens between 1525 – 1625°F.


  • + .020 up to .035 on thickness

  •  + 1/16″ up to 1/8″ on width


  •  3/8″ up to 1 3/4″ dia. +.000 – .004

  •  2″ up to 15″ dia. +/- 1/16”

 Hardening Temp.:   1525  through 1625°F

 Quench Medium:   Oil

 Tempering Range:    400  through 1300°F

 Typical Hardness Level:    26 to 32 R/C

 Anneal Temp.:    1450  thru 1550°F

 Forging Temp:     2100 thru 2200°F

 4140/42PH Material In Stock

 Color Code:     BLUE

 Flat Dimensions

  • ¼” x 1″ up to 6″ x 6″

  • Non-standard sizes, quoted upon request

 Round Dimensions

  • 3/8″ up to 24″

  • Non-standard sizes, quoted upon request

 4140/42 Pre-Hard Typical Analysis











 · Slight variations from typical analysis shown may occur in order to maintain the desired graphitizing potential.