ExELL™ 420-SMDQDownload ExELL™ 420-SMDQ Spec sheet
ExELL™ 420-SMDQ is a premium grade stainless steel used in many tooling applications with these typical properties:
- Good corrosion resistance
- Very good polishability
- Excellent steel cleanliness
- High working hardness/strength
- Good wear resistance
- Very good stability in hardening
Corrosion resistance. For extruding or molding corrosive materials such as PVC and acetates and for molds or engineering parts subjected to mild corrosives or to humid working or storage conditions.
Very good surface finish: When polishability requires an excellent surface for release, minimal stress raisers, the molding production of most optical parts of the molding of medical and the food industry parts such as containers.
Good wear resistance. Very suitable for certain adhesive or abrasive wear resistance requirements. For molding abrasive filled plastics and for long or high production runs.
|USE||Typical Hardness HRC|
|Extrusion or Pultrusion Dies||46–54|
|Compression or Transfer Molds||50–54|
|Blow molds for PET or PVC||46–54|
Note:Most applications of ExELL™ 420-SMDQ utilize the optimum combination of corrosion resistance, hardness and toughness properties attained by heat treatment with hardening at 1870F and double tempering at 480F.
Coefficient of Thermal Expansion, in/in/F
|70 – 400 F||0.0000060|
|70 – 600 F||0.0000064|
Thermal Conductivity, BTU in/ft2 hr F
Modulus of Elasticity, psi
Specific Heat, Btu/ibF
Ac1 – 1470F
Ac3 – 1580F
Ms – 325F
After rough machining of an annealed component, heat the part to 1200F, equalize and hold 1 – 2 hours. Furnace cool to 900F and then air cool to room temperature.
With a protective atmosphere or vacuum furnace, heat slowly to 1450F. Equalize and hold one hour per inch of thickness. Furnace cool 20F/hr to 1200F and equalize. Air cool to room temperature. Hardness – 229 HB max.
HARDENING AND QUENCHING
Protect against decarburization and oxidation during austenitizing.
Preheating: Heat to 1200F and equalize. Continue heating to 1550F and equalize. Complete heating to hardening temperature.
Hardening: Typical austenitizing range is 1870 – 1920F. Hardening temperature can be adjusted to develop maximum hardness. A hardening temperature of 1870 – 1880F is normally used for most applications while 1910 – 1920F can be used for maximum hardness.
|Hardening Temperature||Hold Time*||As-Quenched Hardness|
|1870F||30 min.*||56±2 HRC|
|1910F||30 min||57±2 HRC|
*Hold time = time at temperature after tool is fully heated through.
Quenching: Quenching should be performed as rapidly as possible without promoting excessive movement or cracking. Typical quenching media include:
- High speed gas with sufficient positive pressure in vacuum furnace
- Circulating air/atmosphere
- Martempering bath or fluidized bed at 480–1020F, then air cool to room temp.
- Warm oil
Temper immediately after quenching to about 150F. Temper a minimum of two times with intermediate cooling to room temperature.
Choose the tempering temperature to develop required hardness. (However, tempering at 480F is recommended for the optimum balance of hardness, toughness, corrosion resistance and dimensional stability.) ExELL™ 420-SMDQ should be heated to the desired tempering temperature and held a minimum of two hours. Air cool to room temperature. Check hardness and adjust temperature for additional tempering operation(s). Repeat for added tempers.
Typical tempering temperature responses follow (use for approximate guideline only):
|Tempering Temperature||Harden 1780F HRC||Harden 1910F HRC|
*Avoid tempering between 750–1020F due to risk of temper embrittlement and loss of corrosion resistance.
Typical tensile & yield strength at RT
|52 HRC||46 HRC|
|Tensile Strength, psi||255,000||210,000|
|0.2% Yield Strength, psi||215,000||185,000|
ExELL™ 420-SMDQ resists rusting and staining due to humid service or storage conditions. Additionally, ExELL™ 420-SMDQ will resist typical corrosion by water, water vapor, weak organic acids and when molding corrosive plastics under normal conditions.
ExELL™ 420 SMDQ will exhibit maximum corrosion resistance when using a low temperature temper (480F) in heat treatment and when polished to a very fine finish.
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 integrated producer, 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 products described or suitability for a particular application. Ellwood Specialty Steel reserves the right to make changes in practices which may render some information outdated or obsolete. Ellwood Specialty Steel should be consulted for current information and/or capabilities.