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Download 15-5PH Spec sheet

ExELL™ 15-5 PH Stainless Mold Steel

ExELL™ 15-5 PH was developed by Ellwood Specialty Steel as a premium quality mold steel. ExELL™ 15-5 PH is a martensitic precipitation hardening stainless steel with certain advantages over conventional stainless mold steels. Some of these characteristics include:

  • Superior corrosion resistance
  • Simple heat treatment
  • Uniformity of mechanical properties
  • Easy to weld
  • Excellent polishability
  • Good dimensional stability
  • Very good toughness


C 0.04 Cr 15.20
Mn 0.70 Ni 4.80
Si 0.30 Cu 3.70
Mo 0.25 Cb 0.30



ExELL™ 15-5 PH is used in various tooling and engineered parts. Some typical applications are:

  • Injection molds for various plastics and rubbers
  • Medical and food industry tooling
  • Extrusion dies
  • Compression molds
  • Plastic processing equipment
  • Manifold parts
  • Glass molds
  • Engineered components


Physical Properties:

Coefficient of Thermal Expansion, in/in/F

400 F ___________ 0.000006

Thermal Conductivity, BTU in/ft2 hr F

70 F ___________ 130

400 F __________ 155

Density, lbs/

70 F ___________ 0.283

Modulus of Elasticity, psi

70 F ___________ 29,000,000

400 F __________ 27,700,000

Specific heat, Btu/lb F

70 F ___________ 0.11

HEAT TREATMENT (General Recommendations)

ExELL™ 15-5 PH is normally supplied in either the solution annealed condition or the solution annealed plus aged condition. However, the following thermal treat data may be useful if stress relieving, aging or re-solution annealing might be necessary.


Stress relieving after aging is generally not performed because of the risk of undesired aging. Stress relieving will simultaneously age harden the material. Thus it is very useful to perform major machining in the solution annealed condition, then age the part as required. The aging treatment in this context will both precipitation harden and stress relieve the material.


Solution annealing ExELL™ 15-5 PH should not be necessary. However, if aged material requires to be re-solution annealed treat as follows. Heat to 1900F, equalize, hold 30 minutes at temperature and air quench. Movement and distortion are likely. Resulting hardness will be ~ 30-33 HRC.


If ExELL™ 15-5 PH was not supplied in a specified aged condition (prehardened), the material can be age hardened with an aging temperature generally between 925° and 1150°F. The aging temperature is typically selected to attain a desired hardness level.

Condition Aging Temp Hardness (HRC)
H925 925°F ~42–44
H975 975°F ~39–41
H1025 1025°F ~38–40
H1150 1150°F ~33–35


Aging is performed by uniformly heating to the aging temperature, equalizing temperature from surface to center, holding 4 hours at temperature and air cooling. Slight shrinkage will occur after aging on the order of about 0.0005 to 0.0010 inches per inch.

Most aging is accomplished by using a 975°F age or higher. A 975°F aging treatment is used for a certain balance of hardness and toughness while higher temperature aging treatments will improve toughness and minimize over-aging if higher service temperatures are encountered.


FEATURE Typical Hardness P-20
302 HB
293 HB
420F.m320 HB S-755 HRC H-1352 HRC 42050 HRC 15-5PH40 HRC
Strength 2 1 2 9 7 6 4
Wear Resistance 1 1 1 7 6 5 4
Toughness 8 4 4 3 3 2 6
Texturing 6 1 1 5 5 5 8
Polishability 3 1 1 6 7 7 6
Corrosion Resistance 1 1 4 1 1 6 8
Machinability* 4 6 5 6 6 6 3
Weldability 6 4 2 4 4 4 8
Nitriding Ability 6 5 n/a 4 7 n/a n/a
Flame Hardening 7 7 2 2 2 2 n/a


*Machinability of P-20, Holder, 420F and 15-5PH is rated in the pre-hardened condition. S-7, H-13 and 420 are rated in the annealed condition. Overall ratings are 1-10 where 1 is the lowest rating.


For any additional information to include welding, machining, grinding or EDM processing, nitriding, polishing or texturing, please contact Ellwood Specialty Steel direct at 800-932-2188.


Ellwood Specialty Steel is a fully integrated producer of a wide range of specialty tool steels.

Our ExELL™ grades are made with the advanced ASEA-SKF steel making capabilities which include an ultra high powered electric arc furnace with subsequent state of the art ladle refining and vacuum degassing equipment for the most complete and modern ladle metallurgy technology.

Our steel making expertise and capability is further enhanced from a long forging history with optimum forging and heat treating practices to develop very special material characteristics of product uniformity, cleanliness, machinability, polishability, strength, toughness, hardenability and other steel properties. All this from production facilities certified to ISO 9002.


Ellwood Specialty Steel is committed to providing products and services which will consistently meet or exceed all quality and performance expectations. We will provide customer and technical service that will ensure complete satisfaction.

Being a very flexible provider,Ellwood Specialty Steel will establish product programs to fully support industry or customer requirements. Our extensive stock programs are supported by very short mill lead times of custom forged products. Customized stock programs are and can be available for specific customer needs.

This information is intended to provide general data on our products and their uses and is based on our knowledge at the time of publication. No information should be construed as a guarantee of specific properties of the product described or suitability for a particular application. Ellwood Specialty Steel reserves the right to make changes in practices that may render some information outdated or obsolete. Ellwood Specialty Steel should be consulted for current information and/or capabilities.



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