Steel C30-HR (Hot rolled)
Supply condition
EN C30 · AISI/SAE 1030 · JIS S30C · GB 30
Cheapest stock condition for weldments, brackets and parts to be machined and later heat treated.
Values for the HR condition
Other C30 tempers and conditions
C30 is listed in 11 conditions; see the grade overview at C30.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
HRThis page Hot rolled | Cheapest stock condition for weldments, brackets and parts to be machined and later heat treated. | 260 | 470 | 20 | 137 HB | — |
Spheroidize annealed | Choose for cold heading, thread rolling or severe cold forming of fasteners and forged blanks. | 290 | 440 | 35 | 120 HB | 10.5 % IACS |
Solution annealed | Softest, most stable condition for deep machining, cold bending or stress-free blanks before hardening. | 340 | 465 | 31 | 126 HB | — |
NDefault Normalized | Pick the normalized 870–900 °C air-cooled delivery and test condition for uniform fine pearlite balancing 345 MPa yield, 30% elongation and machinability before any further hardening. | 345 | 520 | 30 | 149 HB | — |
Induction hardened | Pick when journals or teeth need a hard wear surface (≈50 HRC) on a tough, ductile core. | 360 | 560 | 22 | 52 HRC | 10 % IACS |
Cold drawn | Bright, close-tolerance bar with higher yield and better surface finish; use where no further heat treatment is planned. | 440 | 525 | 12 | 149 HB | — |
Q&T 650 °C | High-temper condition when maximum toughness and machinability are wanted after hardening. | 441 | 586 | 32 | 17 HRC | — |
Q&T 540 °C | Most common quenched-and-tempered condition for general machine shafts and forgings. | 517 | 669 | 28 | 25 HRC | — |
Q&T 425 °C | Use quenching with 425 °C tempering (≈32 HRC) for loaded shafts requiring about 731 MPa tensile; hardness rises to 302 HB while elongation falls to 23%. | 579 | 731 | 23 | 32 HRC | — |
Q&T 315 °C | High strength with modest ductility for small hardened pins and levers. | 621 | 800 | 19 | 42 HRC | — |
Q&T 205 °C | Maximum hardness/wear on thin sections; low toughness, use only for small wear parts. | 648 | 848 | 17 | 50 HRC | — |
What is C30-HR?
C30-HR is C30 supplied in the HR condition — cheapest stock condition for weldments, brackets and parts to be machined and later heat treated. C30-HR has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 92% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi). C30-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). N is the default condition FabDigit quotes; HR is available on request or by drawing note.
Advantages
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
Limitations
- Low strength — 260 MPa (37.7 ksi), worse than 92% of steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 78% of steel grades
C30-HR properties
Typical room-temperature values for C30-HR; 13 are specific to this condition. Other listed values are C30 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
C30-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).
Mechanical16
C30-HR has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 92% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
C30-HR is rated for continuous service to 400°C (752 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
C30-HR conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of C30-HR takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
C30-HR's machinability is good (58/100, better than 75% of steel grades); weldability good (68/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C30-HR
Is C30 easy to machine?
Machines readily at ~70 % of 1212 in the normalized or cold-drawn state; annealed material can smear, so use sharp carbide, 120–200 m/min and good coolant.
Can C30 be welded?
Weldable by SMAW/GMAW with low-hydrogen consumables; at 0.30 % C preheat 100–150 °C and post-weld stress relief on thick or restrained joints to avoid HAZ cracking.
Can C30 be formed, bent or molded?
Good hot forgeability at 1100–1200 °C; cold bending needs generous radii (≥2t) and is best done annealed or spheroidized.
What surface finishes work on C30?
No anodizing — protect with zinc/nickel plating, phosphate + oil, black oxide or paint; takes a fine polish but will flash-rust unless coated.
C30 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/T 699 steel 30; AISI 1030 = 0.28-0.34 | 0.27 – 0.34 | 0.3 |
| Si | 0.17 – 0.37 | 0.25 |
| MnAISI 1030 = 0.60–0.90 | 0.5 – 0.8 | 0.65 |
| PC30E/1.1178 ≤0.025 | ≤ 0.04 | 0.02 |
| SC30E ≤0.035, C30R sulfur-treated | ≤ 0.04 | 0.02 |
| Crresidual | ≤ 0.25 | 0.05 |
| Niresidual | ≤ 0.3 | 0.05 |
| Curesidual | ≤ 0.25 | 0.05 |
| Fe | balance | — |
C30-HR — frequently asked
What is C30-HR used for?
C30-HR is typically used for shafts, bolts, small forgings, machine parts and gears (light duty). In short: most weldable medium carbon; good machinability and formability; lower-strength C35 alternative.
What is the yield strength of C30-HR?
C30-HR has a typical yield strength of 260 MPa (37.7 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 92% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is C30-HR easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines readily at ~70 % of 1212 in the normalized or cold-drawn state; annealed material can smear, so use sharp carbide, 120–200 m/min and good coolant.
Can C30-HR be welded?
Yes — weldability is rated good (68/100). Weldable by SMAW/GMAW with low-hydrogen consumables; at 0.30 % C preheat 100–150 °C and post-weld stress relief on thick or restrained joints to avoid HAZ cracking.
What surface finishes work on C30-HR?
No anodizing — protect with zinc/nickel plating, phosphate + oil, black oxide or paint; takes a fine polish but will flash-rust unless coated.
Can C30-HR be formed, bent or molded?
Good hot forgeability at 1100–1200 °C; cold bending needs generous radii (≥2t) and is best done annealed or spheroidized.
What is the maximum service temperature of C30-HR?
C30-HR is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C30-N and C30-QT205?
N is the default condition — pick the normalized 870–900 °C air-cooled delivery and test condition for uniform fine pearlite balancing 345 MPa yield, 30% elongation and machinability before any further hardening. QT205: maximum hardness/wear on thin sections; low toughness, use only for small wear parts. Yield strength is 345 MPa in N versus 648 MPa in QT205.
Sources
- EN 10083-2 / EN 10277 (C30, C30E, 1.0528/1.1178) — CEN (2006)
- ASTM A29/A29M and SAE J403 (1030) — ASTM / SAE (2020)
- JIS G 4051 (S30C) — JSA (2016)
- 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.