S7
Download S7 Spec sheetExELL™ S-7 SMDQ was developed by Ellwood Specialty Steel as a premium tooling quality chromium-molybdenum alloy tool steel for die and mold applications.
ExEll™ S-7 SMDQ is characterized by:
- Excellent cleanliness
- Very good honogeniety
- High toughness
- Good impact and wear resistance
- Very good polishability
- Good flame and through hardening properties
- Good dimensional stability during hardening
| Typical Analysis | |||
| C | 0.50 | Mn | 0.70 |
| Si | 0.30 | Cr | 3.25 |
| S | 0.005max | Mo | 1.50 |
APPLICATIONS
ExELL™ S-7 SMDQ is very suitable for heavy duty blanking and forming tools because of the good combination of toughness and wear resistance. Typical applications include upgraded tooling for stamping, blanking, punching, cropping, shearing, trimming, cold compacting, heading and other forming tools.
With the very good cleanliness and homogenous structure, ExELL™ S-7 SMDQ is an excellent choice for plastic mold applications. ExELL™ S-7 SMDQ is regularly used for high quality plastic injection, compression and transfer molds.
CHARACTERISTICS
Coefficient of Thermal Expansion, in/in/F
400 F………0.0000069
Thermal Conductivity, BTU in/ft2 hr F
70 F………201
400 F………210
Density, lbs/cu.in.
70F……….0.2833
Modulus of Elasticity, psi
70F………29,000,000
400F………28,000,000
Specific Heat, Btu/lbF
70F………0.11
Critical Temperatures
Ac3………1500F
Ac1………1360F
Ms………425F
HEAT TREATMENT (General Recommendations)
Surface Treatments
If a locally higher hardness is required, ExELL™ S-7 SMDQ lends itself readily to flame or induction hardening to 58-60 (air cooling. Surfaces of ExELL™ S-7 SMDQ can also be easily chrome plated or nitrided with typical or standard methods.
Stress Relieving
To minimize movement during heat treatment, a stress relieve can be used between the rough and finish machine opera0ons of tool making before heat treatment. After rough machining, heat treat the part(s) to equalize and hold 1 – 2 hours. Furnace cool to 900F and then air cool.
Annealing
With a protective atmosphere or vacuum furnace, heat slowly to 1530F. Equalize and hold on hour per inch of thickness. Furnace cool 20F/hr to 1000F and equalize. Air cool to room temperature.
Hardness – 217 HB max.
TOOLMAKING
For any additional information including flame hardening, welding, machining, grinding, EDM processing, nitriding, or polishing, please contact Ellwood Specialty Steel direct at 800-932-2188.
Hardening and Quenching
Preheating: Heat to 1200-1250F and equalize. Continue heating to hardening temperature.
Hardening: Protect against oxidation and decarburization. Austentizing (hardening) temperature range is 1690-1780F but hardening is usually at 1725F.
Typical response is:
| Hardening Temperature | Hold Time* | As-Quenched Hardness |
1700F60 Min.56-60 HRC1725F45 min.57-61 HRC1750F30 min.57-61 HRC
*Hold time = time at temperature after tool is fully heated through.
Quenching: Typical quenching media include:
- Circulating air or atmosphere
- Forced air or gas
- Step quench
- Oil (large cross sections)
Temper as soon as quenching temperature reaches 120 – 150F.
Tempering
Temper immediately after quenching to about 150F. Temper two times with intermediate cooling to room temperature.
ExELL™ S-7 SMDQ should be heated to the desired tempering temperature (40F minimum) and held a minimum of two hours. Select the tempering temperature based on required hardness (tempering between 700-800F should be avoided to avoid temper embrittlement). Air cool to room temperature. Check hardness and adjust temperature for additional tempering opera0ons. Repeat for second temper.
Typical tempering temperature responses follow. (Use for approximate guideline only)
| Hardening Temperature | Hardness HRC |
400F58480F55930F521025F491100FF44
MECHANICAL PROPERTIES
| Hardness HRC | Compressive Yield Strength |
58300,000 psi
55295,000 psi50240,000 psi45200,000 psi40160,000 psi35120,000 psi
Typical impact strengths at room temperature versus tempering temperature are:
| Tempering Temperature | Impact Strength Charpy KCU ft lb |
| 400F | 8.5 |
| 480F | 10.0 |
| 750F | 6.0 |
| 930F | 8.0 |
| 1025F | 10.0 |
CAPABILITIES
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 op0mum 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.
QUALITY ASSURANCE
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.
