Steel S2 · heat-treated state
Steel S2 Q&T
Properties of the Q&T condition, compared with the other S2 tempers.
General hardened-and-tempered service condition (typically 54–58 HRC) for shock tools and bits.
What is S2 Q&T?
S2 Q&T is S2 heat treated to Q&T — general hardened-and-tempered service condition (typically 54–58 HRC) for shock tools and bits. S2 Q&T has a yield strength of 1,700 MPa (247 ksi) and a tensile strength of 2,000 MPa (290 ksi) — stronger than 99% of steel grades. Elongation at break is 6% and the elastic modulus is 207 GPa (30 Msi). S2 Q&T has a density of 7.79 g/cm³ (0.281 lb/in³), lighter than 90% of steel grades. It melts at 1,425°C (2,597 °F). Annealed is the default condition FabDigit quotes; Q&T is available on request or by drawing note.
Advantages
- High strength — 1,700 MPa (247 ksi), better than 99% of steel grades
Limitations
- Difficult to machine — 12/100, worse than 99% of steel grades
- Limited formability — 5/100, worse than 99% of steel grades
- Limited ductility — 6%, worse than 98% of steel grades
- Low fracture toughness — 35 MPa·√m (31.9 ksi·√in), worse than 95% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
S2 Q&T properties
Typical room-temperature values for S2 Q&T — 15 properties are specific to this condition; the rest are grade-level values shared by every S2 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
S2 Q&T has a density of 7.79 g/cm³ (0.281 lb/in³), lighter than 90% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
S2 Q&T has a yield strength of 1,700 MPa (247 ksi) and a tensile strength of 2,000 MPa (290 ksi) — stronger than 99% of steel grades. Elongation at break is 6% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
S2 Q&T is rated for continuous service to 200°C (392 °F). It conducts heat at 25.5 W/m·K (14.7 BTU/hr·ft·°F), worse than 87% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
S2 Q&T conducts electricity at 5.5 % IACS, worse than 81% of steel grades.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of S2 Q&T takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 45%.
Manufacturability8
S2 Q&T's machinability is not recommended (12/100, worse than 99% of steel grades); weldability poor (15/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other S2 tempers and conditions
S2 is also supplied in 5 other conditions. The full side-by-side table is on the S2 overview.
- AnnealedDefaultStandard stock condition (183–217 HB) for machining, forming and drilling before hardening.460 MPa yield · 200 HB
- Hardened & TemperedMaximum-hardness condition for screwdriver bits and punch tips where wear beats toughness.1,900 MPa yield · 59 HRC
- Q&TGeneral hardened-and-tempered service condition (typically 54–58 HRC) for shock tools and bits.1,700 MPa yield · 57 HRC
- H&T 50-54 HRCToughest practical working condition for chisels, rivet sets and pneumatic-hammer tooling under heavy shock.1,500 MPa yield · 52 HRC
Working with S2 Q&T
Is S2 easy to machine?
Machine in the annealed condition with sharp carbide or cobalt HSS at moderate speed; the ~1 % Si makes chips gummy, so use generous coolant and finish-grind after hardening.
Can S2 be welded?
Not a welding grade — repair only, with 200–320 °C preheat, matching or austenitic filler, and an immediate re-temper to avoid quench cracks.
Can S2 be formed, bent or molded?
Forge 1010–1150 °C, never below ~900 °C, slow cool then anneal 760–790 °C; harden 845–885 °C with a severe water/brine quench (thin sections may be oil-quenched) and temper 175–370 °C for 50–60 HRC.
What surface finishes work on S2?
Grind, then protect with black oxide, manganese phosphate or oil; thin electroplating requires post-plate bake (~190 °C) to avoid hydrogen embrittlement.
S2 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 | 0.4 – 0.55 | 0.5 |
| Siraises hardenability and tempering resistance | 0.9 – 1.2 | 1.05 |
| Mn | 0.3 – 0.5 | 0.4 |
| Mo | 0.3 – 0.6 | 0.45 |
| Voptional grain refiner | ≤ 0.5 | 0.2 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
S2 Q&T — frequently asked
What is S2 Q&T used for?
S2 Q&T is typically used for screwdrivers, pneumatic tool bits and chisels. In short: tough; water-hardening tool.
What is the yield strength of S2 Q&T?
S2 Q&T has a typical yield strength of 1,700 MPa (247 ksi) and a tensile strength of 2,000 MPa (290 ksi) — stronger than 99% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is S2 Q&T easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Machine in the annealed condition with sharp carbide or cobalt HSS at moderate speed; the ~1 % Si makes chips gummy, so use generous coolant and finish-grind after hardening.
Can S2 Q&T be welded?
Not readily — weldability is rated poor (15/100). Not a welding grade — repair only, with 200–320 °C preheat, matching or austenitic filler, and an immediate re-temper to avoid quench cracks.
What surface finishes work on S2 Q&T?
Grind, then protect with black oxide, manganese phosphate or oil; thin electroplating requires post-plate bake (~190 °C) to avoid hydrogen embrittlement.
Can S2 Q&T be formed, bent or molded?
Forge 1010–1150 °C, never below ~900 °C, slow cool then anneal 760–790 °C; harden 845–885 °C with a severe water/brine quench (thin sections may be oil-quenched) and temper 175–370 °C for 50–60 HRC.
What is the maximum service temperature of S2 Q&T?
S2 Q&T is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in S2 Q&T?
Yes — S2 Q&T is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A681 — Standard Specification for Tool Steels Alloy — ASTM International (2022)
- 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)
- Shock-resisting tool steel S2 data sheet — Tool-steel producers (Crucible/Böhler/Hudson-type datasheets) (2020)
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.