Steel 1086 QT-42HRC
Hardness band
AISI/SAE 1086 · UNS G10860 · EN 1.1269
QT-42HRC = q&T 40–45 HRC
Tougher temper for shock-loaded wear parts where 50 HRC would chip.
Values for the QT-42HRC condition
Other 1086 tempers and conditions
1086 is listed in 8 conditions; see the grade overview at 1086.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
A | Softest, most machinable and most cold-formable condition; the standard delivery state for tool and spring blanks. | 380 | 655 | 24 | 192 HB | — |
HRDefault Hot rolled | Standard mill-supplied condition for bar and coil that will be spheroidized, machined or hardened by the user. | 540 | 930 | 12 | 27 HRC | — |
Normalized | Use to homogenize coarse as-rolled or forged structure and refine grain before hardening. | 560 | 1,010 | 11 | 31 HRC | — |
spheroidize annealed then cold drawn | Choose for close-tolerance bright bar that still machines and cold-heads reasonably before hardening. | 655 | 790 | 10 | 235 HB | 9.5 % IACS |
Cold drawn | General cold-finished bar with better surface and tolerance than hot rolled but higher residual stress. | 700 | 830 | 8 | 24 HRC | 9.6 % IACS |
QT-42HRCThis page Q&T 40–45 HRC | Tougher temper for shock-loaded wear parts where 50 HRC would chip. | 1,180 | 1,380 | 9 | 42 HRC | — |
Q&T 48–52 HRC | Spring/tool temper balancing high elastic limit with some toughness; typical for leaf springs and hand tools. | 1,450 | 1,700 | 6 | 50 HRC | — |
Q&T 58–62 HRC | Maximum hardness and edge retention for blades, files, scrapers and wear plates; very brittle, keep sections thin. | 1,700 | 2,100 | 2 | 60 HRC | — |
What is 1086 QT-42HRC?
1086 QT-42HRC is 1086 heat treated to QT-42HRC — tougher temper for shock-loaded wear parts where 50 HRC would chip. 1086 QT-42HRC has a yield strength of 1,180 MPa (171 ksi) and a tensile strength of 1,380 MPa (200 ksi) — stronger than 94% of steel grades. Elongation at break is 9% and the elastic modulus is 205 GPa (29.7 Msi). 1086 QT-42HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,410°C (2,570 °F). HR is the default condition FabDigit quotes; QT-42HRC is available on request or by drawing note.
Advantages
- High strength — 1,180 MPa (171 ksi), better than 94% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- High electrical conductivity — 9.6 % IACS, better than 78% of steel grades
Limitations
- Difficult to machine — 20/100, worse than 97% of steel grades
- Limited ductility — 9%, worse than 93% of steel grades
- Low fracture toughness — 40 MPa·√m (36.4 ksi·√in), worse than 92% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
1086 QT-42HRC properties
Typical room-temperature values for 1086 QT-42HRC; 12 are specific to this condition. Other listed values are 1086 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
1086 QT-42HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,410°C (2,570 °F).
Mechanical16
1086 QT-42HRC has a yield strength of 1,180 MPa (171 ksi) and a tensile strength of 1,380 MPa (200 ksi) — stronger than 94% of steel grades. Elongation at break is 9% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
1086 QT-42HRC is rated for continuous service to 350°C (662 °F). It conducts heat at 47 W/m·K (27.2 BTU/hr·ft·°F), better than 75% of steel grades. Thermal expansion is 11.4 µm/m·K (6.33 µin/in·°F).
Electrical3
1086 QT-42HRC conducts electricity at 9.6 % IACS, better than 78% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 1086 QT-42HRC takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
1086 QT-42HRC's machinability is poor (20/100, worse than 97% of steel grades); weldability poor (15/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1086 QT-42HRC
Is 1086 easy to machine?
Machine in the spheroidize-annealed condition (≈65% of 1212); use rigid setups, sharp carbide or coated HSS and low-to-moderate speeds — hardened 1086 needs grinding or EDM.
Can 1086 be welded?
Poor weldability (CE ≈ 0.9): preheat 250–350 °C, low-hydrogen consumables, slow cooling and immediate stress-relief/temper, or avoid welding entirely.
Can 1086 be formed, bent or molded?
Cold form only in the annealed/spheroidized state with generous bend radii; hot work 1100→850 °C, then slow cool or normalize to avoid hard as-forged martensite.
What surface finishes work on 1086?
No natural corrosion resistance — specify oil, black oxide, phosphate, zinc or paint; grind and polish after hardening, and shot peen springs to boost fatigue life.
1086 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 |
|---|---|---|
| CSAE J403 / ASTM A29 | 0.8 – 0.93 | 0.86 |
| Mn | 0.3 – 0.5 | 0.4 |
| Pmax, bar products | ≤ 0.04 | 0.02 |
| Smax, bar products | ≤ 0.05 | 0.03 |
| Sitypical for killed steel; not always specified | 0.1 – 0.3 | 0.22 |
| Fe | balance | — |
1086 QT-42HRC — frequently asked
What is 1086 QT-42HRC used for?
1086 QT-42HRC is typically used for springs, blades, wire products and cutting tools. In short: tighter chemistry than 1084; hardens to 60 HRC; spring and blade grade.
What is the yield strength of 1086 QT-42HRC?
1086 QT-42HRC has a typical yield strength of 1,180 MPa (171 ksi) and a tensile strength of 1,380 MPa (200 ksi) — stronger than 94% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 1086 QT-42HRC easy to machine?
Not especially — machinability is rated poor (20/100, worse than 97% of steel grades). Machine in the spheroidize-annealed condition (≈65% of 1212); use rigid setups, sharp carbide or coated HSS and low-to-moderate speeds — hardened 1086 needs grinding or EDM.
Can 1086 QT-42HRC be welded?
Not readily — weldability is rated poor (15/100). Poor weldability (CE ≈ 0.9): preheat 250–350 °C, low-hydrogen consumables, slow cooling and immediate stress-relief/temper, or avoid welding entirely.
What surface finishes work on 1086 QT-42HRC?
No natural corrosion resistance — specify oil, black oxide, phosphate, zinc or paint; grind and polish after hardening, and shot peen springs to boost fatigue life.
Can 1086 QT-42HRC be formed, bent or molded?
Cold form only in the annealed/spheroidized state with generous bend radii; hot work 1100→850 °C, then slow cool or normalize to avoid hard as-forged martensite.
What is the maximum service temperature of 1086 QT-42HRC?
1086 QT-42HRC is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1086-HR and 1086 A-SPH?
HR is the default condition — standard mill-supplied condition for bar and coil that will be spheroidized, machined or hardened by the user. A-SPH: softest, most machinable and most cold-formable condition; the standard delivery state for tool and spring blanks. Yield strength is 540 MPa in HR versus 380 MPa in A-SPH.
Sources
- SAE J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- ASTM A682/A684 — High-Carbon Cold-Rolled Spring Steel Strip — ASTM (2018)
- ASTM A227 / A229 — Hard-Drawn and Oil-Tempered Spring Wire — ASTM (2019)
- GB/T 699 — (85 grade) — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating — ASM International (1991)
- Mysteel / SMM (2025)
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.