Steel 1078
AISI/SAE 1078 · UNS G10780
1078 is a plain high-carbon steel (~0.72–0.86 % C, UNS G10780) that develops its strength from carbon and heat treatment rather than alloying additions.
Reference datasheet — 1078 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the HR condition
1078 tempers and conditions
1078 is supplied in 9 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition; choose for cold forming, deep machining or before final hardening. | 370 | 615 | 22 | 174 HB | 49 W/m·K |
HRDefault Hot rolled | Standard mill condition for bar and coil that will be re-heat-treated by the user; cheapest form. | 385 | 690 | 12 | 200 HB | — |
Normalized | Fine pearlite for uniform structure and higher strength than hot rolled without quenching distortion. | 520 | 1,005 | 11 | 31 HRC | — |
Spheroidize annealed and cold drawn | Best combination of size accuracy, surface finish and machinability for screw-machine parts before hardening. | 570 | 655 | 10 | 192 HB | 9.6 % IACS |
Cold drawn | Standard cold-finished bar: higher strength and tight tolerance, but limited ductility and residual stress. | 700 | 830 | 8 | 22 HRC | — |
Q&T 42-47 HRC | Tough-hard condition for heavy springs, chisels and wear parts needing some shock resistance. | 1,280 | 1,450 | 8 | 45 HRC | 44 W/m·K |
Hardened and blue tempered spring strip | Ready-to-use flat spring, shim and clip stock supplied hardened, tempered and blued. | 1,380 | 1,550 | 3 | 46 HRC | 8.5 % IACS |
Hard drawn spring wire | Heavily patented-and-drawn wire for coil springs used as-coiled with only a low-temperature stress relief. | 1,400 | 1,700 | 3 | 48 HRC | — |
Q&T 56-62 HRC | Maximum hardness and wear resistance for blades, punches and cutting edges; very brittle, avoid impact and notches. | 1,700 | 2,000 | 2 | 59 HRC | 42 W/m·K |
What is 1078?
1078 is a plain high-carbon steel (~0.72–0.86 % C, UNS G10780) that develops its strength from carbon and heat treatment rather than alloying additions. It is supplied mainly as spring wire, strip and bar in HR, annealed, normalized, spheroidize-annealed cold-drawn, hard-drawn and quenched-and-tempered conditions, giving about 385 MPa yield, 690 MPa tensile, 12 % elongation and 200 HB in the default condition, with service to roughly 350 °C. The trade-offs are poor weldability (score 20), limited cold formability (score 30) and no corrosion resistance, so parts are formed soft and hardened afterwards. 1086 is the nearest alternative when higher hardness is required. 1078 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,400°C (2,552 °F). 1078 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 65% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
What is 1078 used for?
- Music wire
- Leaf springs
- Coil springs
- High-strength wire products
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
- High electrical conductivity — 9.5 % IACS, better than 75% of steel grades
Limitations
- Low fracture toughness — 40 MPa·√m (36.4 ksi·√in), worse than 92% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
1078 properties
Typical room-temperature values for 1078-HR; bars are the position among steel grades.
Physical3
1078 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
1078 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 65% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
1078 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 11.3 µm/m·K (6.28 µin/in·°F).
Electrical3
1078 conducts electricity at 9.5 % IACS, better than 75% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (8/100), worse than 99% of steel grades.
Sustainability4
Producing a kilogram of 1078 takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
1078's machinability is fair (40/100, worse than 77% of steel grades); weldability poor (20/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 1078 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 1078
Is 1078 easy to machine?
Machine in the spheroidize-annealed or SACD condition with sharp carbide tooling and generous coolant; hardened stock (>45 HRC) needs grinding or CBN.
Can 1078 be welded?
Poor weldability (CE ≈ 0.9): preheat 260–320 °C, use low-hydrogen consumables and temper immediately after welding; avoid welding on hardened springs.
Can 1078 be formed, bent or molded?
Cold form only when spheroidize annealed; hot work at 1050–1150 °C and never finish below ~800 °C, then slow cool to avoid quench cracks.
1078 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/AISI 1078 carbon range | 0.72 – 0.85 | 0.78 |
| Mn | 0.3 – 0.6 | 0.45 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.05 | 0.03 |
| Sinot specified for rimmed/capped heats; typical for killed steel | 0.15 – 0.35 | 0.25 |
| Fe | balance |
What surface finishes work on 1078?
Not anodizable — protect with oil, black oxide, zinc phosphate, zinc/nickel plating or paint; grind and polish easily to a fine finish when hardened.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 1078 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G10780
- Similar grades
- 80
How much does 1078 cost?
1078 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
1078 — frequently asked
What is 1078 used for?
1078 is typically used for music wire, leaf springs, coil springs and high-strength wire products. In short: heat-treatable spring steel; high strength, low weldability; wear resistance after hardening.
What is the yield strength of 1078?
1078 has a typical yield strength of 385 MPa (55.8 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 65% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 1078 easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Machine in the spheroidize-annealed or SACD condition with sharp carbide tooling and generous coolant; hardened stock (>45 HRC) needs grinding or CBN.
Can 1078 be welded?
Not readily — weldability is rated poor (20/100). Poor weldability (CE ≈ 0.9): preheat 260–320 °C, use low-hydrogen consumables and temper immediately after welding; avoid welding on hardened springs.
What surface finishes work on 1078?
Not anodizable — protect with oil, black oxide, zinc phosphate, zinc/nickel plating or paint; grind and polish easily to a fine finish when hardened.
Can 1078 be formed, bent or molded?
Cold form only when spheroidize annealed; hot work at 1050–1150 °C and never finish below ~800 °C, then slow cool to avoid quench cracks.
What is the maximum service temperature of 1078?
1078 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 1078-HR and 1078 QT-58?
HR is the default condition — standard mill condition for bar and coil that will be re-heat-treated by the user; cheapest form. QT-58: maximum hardness and wear resistance for blades, punches and cutting edges; very brittle, avoid impact and notches. Yield strength is 385 MPa in HR versus 1,700 MPa in QT-58.
How much does 1078 cost?
1078 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- SAE J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements — ASTM (2020)
- ASTM A227 — Steel Wire, Cold-Drawn, for Mechanical Springs — ASTM (2017)
- ASTM A682/A684 — Hardened and Tempered / High-Carbon Steel Strip — ASTM (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating — ASM International (1991)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.