Steel 6CrW2Si QT-40-43HRC
Hardness band
GB 6CrW2Si · AISI/SAE S1
Soft-tempered condition for high-toughness structural tool parts; wear resistance is largely given up.
Values for the QT-40-43HRC condition
Other 6CrW2Si tempers and conditions
6CrW2Si is listed in 8 conditions; see the grade overview at 6CrW2Si.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault spheroidize/soft annealed bar as supplied | Standard stock condition for machining and forming before hardening; ≤285 HB per GB/T 1299. | 450 | 760 | 18 | 240 HB | — |
Cold drawn | Bright, size-accurate small-diameter bar for chisel and punch blanks needing little pre-machining. | 640 | 880 | 10 | 27 HRC | 6.2 % IACS |
Hot rolled | As-rolled or as-forged bar and flats; harder and less uniform — anneal before machining. | 650 | 1,000 | 10 | 34 HRC | 6.2 % IACS |
QT-40-43HRCThis page oil quench 870 °C + temper ~520 °C | Soft-tempered condition for high-toughness structural tool parts; wear resistance is largely given up. | 1,180 | 1,330 | 12 | 42 HRC | 6 % IACS |
oil quench 870 °C + temper ~420 °C | Maximum-toughness hardened state for shanks, drivers and tool bodies subject to severe shock or bending. | 1,350 | 1,550 | 9 | 47 HRC | — |
oil quench 870 °C + temper ~320 °C | Toughness-biased setting for heavy-impact tools such as rivet sets, hot chisel bodies and shear blades. | 1,500 | 1,750 | 6 | 51 HRC | — |
oil quench 870 °C + temper ~250 °C | Common working hardness for pneumatic bits and cold chisels — good balance of edge life and impact resistance. | 1,600 | 1,900 | 4 | 54 HRC | — |
oil quench 870 °C + temper ~200 °C | Maximum hardness condition for chisels and punches where edge retention matters more than shock toughness. | 1,750 | 2,100 | 2 | 57 HRC | — |
What is 6CrW2Si QT-40-43HRC?
6CrW2Si QT-40-43HRC is 6CrW2Si heat treated to QT-40-43HRC — soft-tempered condition for high-toughness structural tool parts; wear resistance is largely given up. 6CrW2Si QT-40-43HRC has a yield strength of 1,180 MPa (171 ksi) and a tensile strength of 1,330 MPa (193 ksi) — stronger than 94% of steel grades. Elongation at break is 12% and the elastic modulus is 207 GPa (30 Msi). 6CrW2Si QT-40-43HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). Annealed is the default condition FabDigit quotes; QT-40-43HRC is available on request or by drawing note.
Advantages
- High strength — 1,180 MPa (171 ksi), better than 94% of steel grades
Limitations
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited formability — 5/100, worse than 99% of steel grades
- Difficult to machine — 18/100, worse than 97% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 87% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
6CrW2Si QT-40-43HRC properties
Typical room-temperature values for 6CrW2Si QT-40-43HRC; 22 are specific to this condition. Other listed values are 6CrW2Si reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
6CrW2Si QT-40-43HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
6CrW2Si QT-40-43HRC has a yield strength of 1,180 MPa (171 ksi) and a tensile strength of 1,330 MPa (193 ksi) — stronger than 94% of steel grades. Elongation at break is 12% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
6CrW2Si QT-40-43HRC is rated for continuous service to 430°C (806 °F). It conducts heat at 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 82% of steel grades. Thermal expansion is 12.4 µm/m·K (6.89 µin/in·°F).
Electrical2
6CrW2Si QT-40-43HRC has an electrical resistivity of 2.85×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 6CrW2Si QT-40-43HRC takes about 35 MJ of energy and emits 2.6 kg of CO₂ — more than 87% of steel grades. Typical recycled content is 35%.
Manufacturability8
6CrW2Si QT-40-43HRC's machinability is poor (18/100, worse than 97% of steel grades); weldability not recommended (10/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 6CrW2Si QT-40-43HRC
Is 6CrW2Si easy to machine?
Machine in the annealed condition (≤285 HB) with rigid setups and cobalt-HSS or coated carbide; after hardening only grinding, EDM or CBN is practical.
Can 6CrW2Si be welded?
Weld only for repair: preheat 300–400 °C, use matched or tool-steel filler, keep interpass hot and re-temper immediately to avoid quench cracking.
Can 6CrW2Si be formed, bent or molded?
Hot forge 1050–1150 °C, stop above ~900 °C and cool slowly, then anneal 800–820 °C furnace-cool; cold forming is limited to mild bending of annealed stock.
What surface finishes work on 6CrW2Si?
Harden from 860–900 °C in oil and temper 200–520 °C to target hardness; finish with grinding plus black oxide, phosphate or oil coating for rust protection.
6CrW2Si 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 | 0.55 – 0.65 | 0.6 |
| Siraises tempering resistance and toughness | 0.5 – 0.8 | 0.65 |
| Mn | ≤ 0.4 | 0.25 |
| Cr | 1 – 1.3 | 1.15 |
| Wcarbide former, grain refinement | 2.2 – 2.7 | 2.45 |
| Niresidual | ≤ 0.25 | — |
| Curesidual | ≤ 0.3 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
6CrW2Si QT-40-43HRC — frequently asked
What is 6CrW2Si QT-40-43HRC used for?
6CrW2Si QT-40-43HRC is typically used for chisels, pneumatic tool bits and punches. In short: impact-tough tool steel; tougher than water-hardening grades; oil-hardening shock grade.
What is the yield strength of 6CrW2Si QT-40-43HRC?
6CrW2Si QT-40-43HRC has a typical yield strength of 1,180 MPa (171 ksi) and a tensile strength of 1,330 MPa (193 ksi) — stronger than 94% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 6CrW2Si QT-40-43HRC easy to machine?
Not especially — machinability is rated poor (18/100, worse than 97% of steel grades). Machine in the annealed condition (≤285 HB) with rigid setups and cobalt-HSS or coated carbide; after hardening only grinding, EDM or CBN is practical.
Can 6CrW2Si QT-40-43HRC be welded?
Not readily — weldability is rated not recommended (10/100). Weld only for repair: preheat 300–400 °C, use matched or tool-steel filler, keep interpass hot and re-temper immediately to avoid quench cracking.
What surface finishes work on 6CrW2Si QT-40-43HRC?
Harden from 860–900 °C in oil and temper 200–520 °C to target hardness; finish with grinding plus black oxide, phosphate or oil coating for rust protection.
Can 6CrW2Si QT-40-43HRC be formed, bent or molded?
Hot forge 1050–1150 °C, stop above ~900 °C and cool slowly, then anneal 800–820 °C furnace-cool; cold forming is limited to mild bending of annealed stock.
What is the maximum service temperature of 6CrW2Si QT-40-43HRC?
6CrW2Si QT-40-43HRC is rated for continuous use to about 430°C (806 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 6CrW2Si Annealed and 6CrW2Si-HR?
Annealed is the default condition — standard stock condition for machining and forming before hardening; ≤285 HB per GB/T 1299. HR: as-rolled or as-forged bar and flats; harder and less uniform — anneal before machining. Yield strength is 450 MPa in Annealed versus 650 MPa in HR.
Sources
- GB/T 1299 (Alloy Tool Steels) — SAC / (2014)
- ASTM A681 Standard Specification for Tool Steels Alloy (S1) — ASTM International (2015)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (Tool Steels) — ASM International (1990)
- Tool Steels, 5th ed. (Roberts, Krauss, Kennedy) — ASM International (1998)
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.