Steel 1070 · supply condition · default condition
Steel 1070-HR
Properties of the HR condition, compared with the other 1070 tempers.
Cheapest stock form for parts that will be re-heat-treated or machined then hardened.
What is 1070-HR?
1070-HR is 1070 supplied in the HR condition — cheapest stock form for parts that will be re-heat-treated or machined then hardened. 1070-HR 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 13% and the elastic modulus is 205 GPa (29.7 Msi). 1070-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Advantages
- Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 90% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 77% of steel grades
1070-HR properties
Typical room-temperature values for 1070-HR — 10 properties are specific to this condition; the rest are grade-level values shared by every 1070 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
1070-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical15
1070-HR 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 13% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
1070-HR is rated for continuous service to 300°C (572 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
1070-HR conducts electricity at 9 % IACS, better than 70% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (9/100), worse than 98% of steel grades.
Sustainability4
Producing a kilogram of 1070-HR takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
1070-HR's machinability is fair (45/100, worse than 65% 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.
Other 1070 tempers and conditions
1070 is also supplied in 9 other conditions. The full side-by-side table is on the 1070 overview.
- HRDefaultCheapest stock form for parts that will be re-heat-treated or machined then hardened.385 MPa yield · 201 HB
- Q&T 50-55HRCUse for cutting edges, scraper blades and wear plates where hardness matters more than toughness.1,600 MPa yield · 52 HRC
- OTReady-to-coil spring wire supplied at final strength — no post-coiling hardening needed, only stress relief.1,400 MPa yield · 46 HRC
- BTPre-hardened thin strip for clips, retaining rings and flat springs formed directly to shape.1,350 MPa yield · 47 HRC
- Q&THighest strength/elastic limit condition for springs, blades and wear parts; accept low ductility and no welding.1,250 MPa yield · 43 HRC
- CDClose tolerance, higher-yield bar or wire for springs, pins and machined parts without further heat treatment.720 MPa yield · 24 HRC
- SACDSpheroidize-annealed to globular carbides for maximum cold workability, then cold drawn — moderate strength with good ductility and improved machinability for cold heading, upsetting and further wire/bar processing.620 MPa yield · 210 HB
- NormalizedUniform fine pearlite with higher strength than as-rolled; good pre-treatment before machining or hardening.500 MPa yield · 26 HRC
- AnnealedPick when the part must be machined, blanked or cold formed before hardening.350 MPa yield · 183 HB
Working with 1070-HR
Is 1070 easy to machine?
Machine in the annealed or spheroidized state with rigid setups, carbide tooling and moderate speeds; above ~35 HRC use CBN/ceramic or switch to grinding.
Can 1070 be welded?
Poor weldability — high carbon equivalent causes hard, crack-prone HAZ; if unavoidable use 200–350 °C preheat, low-hydrogen consumables and immediate post-weld temper.
Can 1070 be formed, bent or molded?
Cold form only in annealed/soft strip condition with generous bend radii; hot forge 1150–850 °C then slow cool or normalize to avoid quench cracks.
What surface finishes work on 1070?
No inherent corrosion protection: use oil, phosphate, black oxide, zinc or paint; after acid pickling or electroplating of hardened parts bake at 190–210 °C to relieve hydrogen embrittlement. Fine pearlitic or tempered structures take a high mirror polish.
1070 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 |
|---|---|---|
| CGB 70 steel: 0.67–0.75 | 0.65 – 0.75 | 0.7 |
| MnGB/T 699 grade 70: 0.50-0.80 | 0.6 – 0.9 | 0.75 |
| Sinot specified in AISI/SAE bar chemistry; GB 70: 0.17–0.37 | 0.15 – 0.35 | 0.25 |
| Pmax, GB 70: ≤0.035 | ≤ 0.04 | 0.02 |
| Smax, GB 70: ≤0.035 | ≤ 0.05 | 0.03 |
| Crresidual (GB limit) | ≤ 0.25 | — |
| Niresidual (GB limit) | ≤ 0.3 | — |
| Curesidual (GB limit) | ≤ 0.25 | — |
| Fe | balance | — |
1070-HR — frequently asked
What is 1070-HR used for?
1070-HR is typically used for saw blades, cutting knives and springs. In short: spring carbon steel.
What is the yield strength of 1070-HR?
1070-HR 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 10 listed tempers.
Is 1070-HR easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in the annealed or spheroidized state with rigid setups, carbide tooling and moderate speeds; above ~35 HRC use CBN/ceramic or switch to grinding.
Can 1070-HR be welded?
Not readily — weldability is rated poor (20/100). Poor weldability — high carbon equivalent causes hard, crack-prone HAZ; if unavoidable use 200–350 °C preheat, low-hydrogen consumables and immediate post-weld temper.
What surface finishes work on 1070-HR?
No inherent corrosion protection: use oil, phosphate, black oxide, zinc or paint; after acid pickling or electroplating of hardened parts bake at 190–210 °C to relieve hydrogen embrittlement. Fine pearlitic or tempered structures take a high mirror polish.
Can 1070-HR be formed, bent or molded?
Cold form only in annealed/soft strip condition with generous bend radii; hot forge 1150–850 °C then slow cool or normalize to avoid quench cracks.
What is the maximum service temperature of 1070-HR?
1070-HR is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1070-HR and 1070-OT?
HR is the default condition — cheapest stock form for parts that will be re-heat-treated or machined then hardened. OT: ready-to-coil spring wire supplied at final strength — no post-coiling hardening needed, only stress relief. Yield strength is 385 MPa in HR versus 1,400 MPa in OT.
Can FabDigit make parts in 1070-HR?
Yes — 1070-HR 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
- SAE J403 / ASTM A29 — Carbon steel bars, grade 1070 — SAE / ASTM (2019)
- ASTM A684 — High-carbon cold-rolled strip — ASTM (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating — ASM International (1991)
- Machining Data Handbook — Metcut Research Associates (1980)
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.