Steel S5 As-Quenched
Heat-treated state
AISI/SAE S5 · UNS T41905
Peak hardness before tempering; must be tempered immediately to avoid cracking.
Values for the As-Quenched condition
Other S5 tempers and conditions
S5 is listed in 4 conditions; see the grade overview at S5.
- Annealed
- Normalized
- Hardened & Tempered
- As-Quenched
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault soft-annealed bar/plate as supplied | Standard stock condition for machining tools before hardening. | 440 | 725 | 25 | 215 HB | — |
900 °C, air cooled | Intermediate condition used to homogenize forgings before spheroidize annealing; not a service condition. | 800 | 1,250 | 10 | 40 HRC | 3.8 % IACS |
58–60 HRC (low temper ~175–205 °C) | Maximum hardness/wear condition for punches and shear blades where impact loads are moderate. | 1,850 | 2,150 | 4 | 59 HRC | — |
As-QuenchedThis page 870 °C oil quench, untempered | Peak hardness before tempering; must be tempered immediately to avoid cracking. | 2,050 | 2,400 | 1 | 63 HRC | 3.5 % IACS |
What is S5 As-Quenched?
S5 As-Quenched is S5 heat treated to As-Quenched — peak hardness before tempering; must be tempered immediately to avoid cracking. S5 As-Quenched has a yield strength of 2,050 MPa (297 ksi) and a tensile strength of 2,400 MPa (348 ksi) — stronger than 100% of steel grades. Elongation at break is 1% and the elastic modulus is 207 GPa (30 Msi). S5 As-Quenched has a density of 7.76 g/cm³ (0.28 lb/in³), lighter than 92% of steel grades. It melts at 1,420°C (2,588 °F). Annealed is the default condition FabDigit quotes; As-Quenched is available on request or by drawing note.
Advantages
- High strength — 2,050 MPa (297 ksi), better than 100% of steel grades
Limitations
- Difficult to machine — 5/100, worse than 100% of steel grades
- Difficult to weld — 5/100, worse than 100% of steel grades
- Limited formability — 2/100, worse than 100% of steel grades
- Limited ductility — 1%, worse than 99% of steel grades
- Limited service temperature — 150°C (302 °F), worse than 99% of steel grades
S5 As-Quenched properties
Typical room-temperature values for S5 As-Quenched; 22 are specific to this condition. Other listed values are S5 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
S5 As-Quenched has a density of 7.76 g/cm³ (0.28 lb/in³), lighter than 92% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
S5 As-Quenched has a yield strength of 2,050 MPa (297 ksi) and a tensile strength of 2,400 MPa (348 ksi) — stronger than 100% of steel grades. Elongation at break is 1% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
S5 As-Quenched is rated for continuous service to 150°C (302 °F). It conducts heat at 21 W/m·K (12.1 BTU/hr·ft·°F), worse than 95% of steel grades. Thermal expansion is 12.4 µm/m·K (6.89 µin/in·°F).
Electrical3
S5 As-Quenched conducts electricity at 3.5 % IACS, worse than 86% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of S5 As-Quenched takes about 36 MJ of energy and emits 2.6 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 40%.
Manufacturability8
S5 As-Quenched's machinability is not recommended (5/100, worse than 100% of steel grades); weldability not recommended (5/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S5 As-Quenched
Is S5 easy to machine?
Machine in the annealed condition (~215 HB) with sharp carbide or HSS tooling; the ~2% Si makes chips gummy, so use positive rake, rigid setups and flood coolant, and finish-grind after hardening.
Can S5 be welded?
Only repair welding is advised: preheat 300–350 °C, use matching or low-hydrogen electrodes, keep interpass heat, then temper immediately at the part's tempering temperature.
Can S5 be formed, bent or molded?
Hot forge 1040–1100 °C, stop above ~900 °C and slow-cool, then spheroidize anneal 760–790 °C; cold forming is limited to light bending in the annealed state.
What surface finishes work on S5?
Harden from 870 °C in oil (or interrupted/marquench), temper at 175–425 °C for 50–60 HRC; protect with black oxide, phosphate or oil — no anodizing, and avoid hard chrome above the temper temperature.
S5 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | 0.5 – 0.65 | 0.58 |
| Sihigh Si gives the shock-resisting character | 1.75 – 2.25 | 2 |
| Mn | 0.6 – 1 | 0.8 |
| Mo | 0.2 – 1.35 | 0.4 |
| Croptional addition per ASTM A681 | ≤ 0.5 | 0.3 |
| Voptional, grain refinement | ≤ 0.35 | 0.2 |
| Niresidual | ≤ 0.3 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
S5 As-Quenched — frequently asked
What is S5 As-Quenched used for?
S5 As-Quenched is typically used for pneumatic chisels, punches, shear and cropping blades, rivet sets and chipping hammers, cold heading and stamping tooling and impact drivers and screwdriver bits. In short: shock-resistant tool steel.
What is the yield strength of S5 As-Quenched?
S5 As-Quenched has a typical yield strength of 2,050 MPa (297 ksi) and a tensile strength of 2,400 MPa (348 ksi) — stronger than 100% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is S5 As-Quenched easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 100% of steel grades). Machine in the annealed condition (~215 HB) with sharp carbide or HSS tooling; the ~2% Si makes chips gummy, so use positive rake, rigid setups and flood coolant, and finish-grind after hardening.
Can S5 As-Quenched be welded?
Not readily — weldability is rated not recommended (5/100). Only repair welding is advised: preheat 300–350 °C, use matching or low-hydrogen electrodes, keep interpass heat, then temper immediately at the part's tempering temperature.
What surface finishes work on S5 As-Quenched?
Harden from 870 °C in oil (or interrupted/marquench), temper at 175–425 °C for 50–60 HRC; protect with black oxide, phosphate or oil — no anodizing, and avoid hard chrome above the temper temperature.
Can S5 As-Quenched be formed, bent or molded?
Hot forge 1040–1100 °C, stop above ~900 °C and slow-cool, then spheroidize anneal 760–790 °C; cold forming is limited to light bending in the annealed state.
What is the maximum service temperature of S5 As-Quenched?
S5 As-Quenched is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in S5 As-Quenched?
Yes — S5 As-Quenched is available for CNC machining; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A681 – Standard Specification for Tool Steels Alloy — ASTM International (2015)
- ASM Handbook Vol.1: Properties and Selection – Irons, Steels, and High-Performance Alloys (Tool Steels) — ASM International (1990)
- Tool Steels, 5th Edition (Roberts, Krauss, Kennedy) — ASM International (1998)
- ASM Handbook Vol.16: Machining — ASM International (1989)
- MatWeb AISI S5 tool steel datasheets — MatWeb LLC (2024)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.