AISI S7 Tool Steel Properties, S7 Material Heat Treating Hardness

0

AISI S7 Tool Steel.

AISI S7 tool steel is a Shock-Resisting Steel with the highest hardenability and elevated temperature softening resistance of the S-series steels. Due to these properties, S7 material is popular in shock-resistant applications. They are moderately resistant to decarburization and grain growth.

S7 Tool Steel Properties

S7 tool steel properties such as chemical composition, physical and mechanical properties are summarized below.

Chemical Composition

Chemical Composition, %
Standard AISI (UNS) C Si Mn P, ≤ S, ≤ Cr Mo V, ≤
ASTM A681 S7 (T41907) 0.45-0.55 0.20-1.00 0.20-0.90 0.030 0.030 3.00-3.50 1.30-1.80 0.35

Physical Properties

Physical Properties Metric Imperial
Density 7.76 g/cm3 0.280 lb/in3
Coefficient of thermal expansion (CTE) 12.6 μm/m·K (20-200 °C) 7.0 μin./in.°F (70-400 °F)
13.3 μm/m·K (20-425 °C) 7.4 μin./in.°F (70-800 °F)
13.7 μm/m·K (20-500 °C) 7.6 μin./in.°F (70-930 °F)
13.3 μm/m·K (20-200 °C) 7.4 μin./in.°F (70-1200 °F)

Mechanical Properties of S7 Steel

Nominal room-temperature mechanical properties of S7 steel

Steel Condition, Fan cooled from 940 °C (1725 °F) and single tempered at: Tensile strength, MPa (ksi) 0.2% yield strength, MPa (ksi) Elongation in 2 in. (50mm), % Reduction in
area, %
Hardness, HRC Charpy unnotched impact, J (ft·lbf)
S7 205 °C (400 °F) 2170 (315) 1450 (210) 7.0 20 58 244 (180)
315 °C (600 °F) 1965 (285) 1585 (230) 9.0 25 55 309 (228)
425 °C (800 °F) 1895 (275) 1410 (205) 10.0 29 53 243 (179)
540 °C (1000 °F) 1820 (264) 1380 (200) 10.0 33 51 324 (239)
650 °C (1200 °F) 1240 (180) 1035 (150) 14.0 45 39 358 (264)
Annealed 640 (93) 380 (55) 25.0 55 95 HRB

Heat Treat for S7 Shock-resisting Tool Steel

The heat treating of S7 tool steel is listed below.

Normalizing and Annealing Temperatures

  • Normalizing: Do not normalize.
  • Annealing: 815-845 °C (1500-1550 °F), the upper limit of the range should be used for large sections and the lower limit for smaller sections. Time held at temperature varies from 1 hour for light sections to 4 hours for heavy sections and large furnace charges of high alloy steel.
  • Rate of cooling: ≤ 14 °C/h (25 °F/h)
  • Annealed Brinell hardness: 187-223 HB.

S7 Material Hardening and Tempering

  • Rate of heating: Slowly
  • Hardening
    • Preheat temperature 650-705 °C (1200-1300 °F);
    • Austenitizing temperature 925-955 °C (1700-1750 °F)
    • Time at temperature: 14-45 minutes for open furnace heat treatment
    • Quenching medium: Air or oil
    • Quenched Rockwell C hardness, 60-61 HRC
  • Tempering temperature: 205-620 °C (400-1150 °F)
  • Approximate tempered Rockwell C hardness: 45-57 HRC

Applications

S7 steel is primarily used for chisels, punches, rivet sets, stamps, screwdrivers and other applications that require high toughness and resistance to shock loads. Also used for hot punching and shearing where some heat resistance is required.

AISI S7 Steel Equivalent Material

AISI S7 steel equivalent material is listed in the table below, including European EN, ISO, German DIN, Chinese GB and Japanese JIS standard, etc.

AISI S7 Tool Steel Equivalent Material
US European Union ISO Germany China Japan Australia India Rusia Korea
Standard Steel (UNS) Standard Steel Name (Material Number) Standard Designation Standard Steel Name (Material Number) Standard Steel Grade Standard Steel Grade Standard Grade Standard Grade Standard Grade Standard Grade
AISI, SAE;
ASTM A681
S7 (T41907) EN ISO 4957 5OCrMoV13-15 (1.2355) ISO 4957 5OCrMoV13-15 DIN EN ISO 4957;
DIN 17350,
5OCrMoV13-15 (1.2355) GB/T 1299 5Cr3MnSiMo1V
Leave A Reply

Your email address will not be published.

We use cookies to improve your experience on our website. By browsing this website, you agree to our use of cookies. Accept Read More

buy levitra buy levitra online