Steel 1080 · hardness band
Steel 1080 Q&T 50-55 HRC
Properties of the Q&T 50-55 HRC condition, compared with the other 1080 tempers.
Blade, cutter and wear-part condition: maximum hardness and edge retention, low impact toughness.
What is 1080 Q&T 50-55 HRC?
1080 Q&T 50-55 HRC is 1080 heat treated to Q&T 50-55 HRC — blade, cutter and wear-part condition: maximum hardness and edge retention, low impact toughness. 1080 Q&T 50-55 HRC has a yield strength of 1,500 MPa (218 ksi) and a tensile strength of 1,800 MPa (261 ksi) — stronger than 97% of steel grades. Elongation at break is 5% and the elastic modulus is 205 GPa (29.7 Msi). 1080 Q&T 50-55 HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,385°C (2,525 °F). HR is the default condition FabDigit quotes; Q&T 50-55 HRC is available on request or by drawing note.
Advantages
- High strength — 1,500 MPa (218 ksi), better than 97% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
- Polishes to a fine finish — 65/100, better than 78% 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 — 5%, worse than 98% of steel grades
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
1080 Q&T 50-55 HRC properties
Typical room-temperature values for 1080 Q&T 50-55 HRC — 12 properties are specific to this condition; the rest are grade-level values shared by every 1080 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
1080 Q&T 50-55 HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,385°C (2,525 °F).
Mechanical15
1080 Q&T 50-55 HRC has a yield strength of 1,500 MPa (218 ksi) and a tensile strength of 1,800 MPa (261 ksi) — stronger than 97% of steel grades. Elongation at break is 5% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
1080 Q&T 50-55 HRC is rated for continuous service to 180°C (356 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 11.3 µm/m·K (6.28 µin/in·°F).
Electrical3
1080 Q&T 50-55 HRC conducts electricity at 9.5 % IACS, better than 74% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 87% of steel grades.
Sustainability4
Producing a kilogram of 1080 Q&T 50-55 HRC takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
1080 Q&T 50-55 HRC's machinability is not recommended (12/100, worse than 99% of steel grades); weldability poor (20/100); 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 1080 tempers and conditions
1080 is also supplied in 8 other conditions. The full side-by-side table is on the 1080 overview.
- HRDefaultCheapest stock form for blanks that will be machined and then hardened; pearlitic as-rolled structure.585 MPa yield · 31 HRC
- Q&T 50-55 HRCBlade, cutter and wear-part condition: maximum hardness and edge retention, low impact toughness.1,500 MPa yield · 52 HRC
- PatentedPatented (sorbitic) and heavily drawn wire for coil springs and wire forms — very high strength as-drawn, no further hardening needed.1,500 MPa yield · 47 HRC
- Q&TBalanced strength/toughness condition for springs, chisels and highly loaded machine parts in thin sections.980 MPa yield · 40 HRC
- CDUse when a bright, close-tolerance bar with higher yield strength is wanted straight from stock.855 MPa yield · 31 HRC
- CRThin strip for saw blades, shims, flat springs and stamped blades; tight thickness and good surface.830 MPa yield · 32 HRC
- SA+CDSpheroidize-annealed (globular carbides in ferrite) then cold drawn — moderate strength with the best cold formability and machinability attainable in 0.80 % C steel, the standard feed condition for cold-heading and pre-hardened spring parts.620 MPa yield · 20 HRC
- NormalizedUniform fine pearlite for consistent machining and predictable response to later hardening.524 MPa yield · 31 HRC
- AnnealedSoftest, most machinable and most formable condition — pick it for heavy machining or cold forming before hardening.375 MPa yield · 174 HB
Working with 1080 Q&T 50-55 HRC
Is 1080 easy to machine?
Machine in the annealed or normalized state with rigid setups, sharp carbide or coated carbide at moderate speed and good flood coolant; hardened 1080 needs grinding or ceramic/CBN tooling.
Can 1080 be welded?
Poor weldability — high carbon equivalent causes hard, crack-prone HAZ; if unavoidable use 200–300 °C preheat, low-hydrogen filler, slow cool and immediate stress relief/temper.
Can 1080 be formed, bent or molded?
Cold form only in the spheroidize-annealed condition and expect large springback; hot form at 950–1150 °C, then normalize before hardening.
What surface finishes work on 1080?
No corrosion resistance: finish with oil, black oxide, phosphate, zinc plating or paint; hardened surfaces take a fine polish and can be shot-peened for fatigue life.
1080 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; GB 80 is 0.77–0.85 | 0.75 – 0.88 | 0.8 |
| MnGB 80 uses 0.17–0.37 Mn | 0.6 – 0.9 | 0.75 |
| Sitypical for killed hot-rolled product; not specified for all bar grades | 0.15 – 0.35 | 0.25 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.05 | 0.03 |
| Fe | balance | — |
1080 Q&T 50-55 HRC — frequently asked
What is 1080 Q&T 50-55 HRC used for?
1080 Q&T 50-55 HRC is typically used for flat and leaf springs, music and patented spring wire, mower and cutter blades, knife blanks, cold-work tool blanks and spiral and clock springs. In short: high-carbon spring bar.
What is the yield strength of 1080 Q&T 50-55 HRC?
1080 Q&T 50-55 HRC has a typical yield strength of 1,500 MPa (218 ksi) and a tensile strength of 1,800 MPa (261 ksi) — stronger than 97% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 1080 Q&T 50-55 HRC easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Machine in the annealed or normalized state with rigid setups, sharp carbide or coated carbide at moderate speed and good flood coolant; hardened 1080 needs grinding or ceramic/CBN tooling.
Can 1080 Q&T 50-55 HRC be welded?
Not readily — weldability is rated poor (20/100). Poor weldability — high carbon equivalent causes hard, crack-prone HAZ; if unavoidable use 200–300 °C preheat, low-hydrogen filler, slow cool and immediate stress relief/temper.
What surface finishes work on 1080 Q&T 50-55 HRC?
No corrosion resistance: finish with oil, black oxide, phosphate, zinc plating or paint; hardened surfaces take a fine polish and can be shot-peened for fatigue life.
Can 1080 Q&T 50-55 HRC be formed, bent or molded?
Cold form only in the spheroidize-annealed condition and expect large springback; hot form at 950–1150 °C, then normalize before hardening.
What is the maximum service temperature of 1080 Q&T 50-55 HRC?
1080 Q&T 50-55 HRC is rated for continuous use to about 180°C (356 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1080-HR and 1080-CD?
HR is the default condition — cheapest stock form for blanks that will be machined and then hardened; pearlitic as-rolled structure. CD: use when a bright, close-tolerance bar with higher yield strength is wanted straight from stock. Yield strength is 585 MPa in HR versus 855 MPa in CD.
Can FabDigit make parts in 1080 Q&T 50-55 HRC?
Yes — 1080 Q&T 50-55 HRC is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- SAE J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- GB/T 699 (grade 80) — SAC (2015)
- ASTM A684/A684M — High-Carbon Steel Strip — ASTM (2021)
- ASTM A227/A229 — Hard-Drawn and Oil-Tempered Spring Wire — ASTM (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating; Vol.16 — Machining — ASM International (1991)
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.