Steel 30CrMnSi-HR (Hot rolled)
Supply condition
GB 30CrMnSi
Cheapest mill condition for stock that will be fully heat treated after rough machining.
Values for the HR condition
Other 30CrMnSi tempers and conditions
30CrMnSi is listed in 8 conditions; see the grade overview at 30CrMnSi.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest state — pick for deep machining, cold forming or thread rolling before final Q&T. | 480 | 750 | 20 | 210 HB | — |
HRThis page Hot rolled | Cheapest mill condition for stock that will be fully heat treated after rough machining. | 520 | 850 | 15 | 240 HB | — |
Normalized | Uniform fine-grain structure for forgings before final quenching, or moderate-strength non-critical parts. | 620 | 950 | 14 | 29 HRC | — |
Cold drawn | Bright close-tolerance bar for shafts and fasteners machined without further heat treatment. | 750 | 900 | 10 | 27 HRC | 7 % IACS |
QT880-520Default Q&T | Standard commercial Q&T condition — best strength/toughness balance for shafts, gears, high-strength bolts and structural fittings. | 900 | 1,120 | 11 | 36 HRC | — |
Q&T | Higher-strength spring/fitting condition (~1300–1450 MPa) where some ductility is still needed. | 1,250 | 1,400 | 8 | 43 HRC | — |
Isothermal (austempered) quench | Choose for thin high-strength parts where distortion and quench cracking must be minimised while keeping toughness at ~1600 MPa. | 1,350 | 1,600 | 8 | 46 HRC | — |
Q&T | Maximum-strength condition (1600–1700 MPa) for aircraft fittings and landing-gear parts; very notch- and hydrogen-sensitive. | 1,400 | 1,650 | 6 | 48 HRC | — |
What is 30CrMnSi-HR?
30CrMnSi-HR is 30CrMnSi supplied in the HR condition — cheapest mill condition for stock that will be fully heat treated after rough machining. 30CrMnSi-HR has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 850 MPa (123 ksi) — stronger than 67% of steel grades. Elongation at break is 15% and the elastic modulus is 205 GPa (29.7 Msi). 30CrMnSi-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). QT880-520 is the default condition FabDigit quotes; HR is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Low fracture toughness — 65 MPa·√m (59.2 ksi·√in), worse than 75% of steel grades
30CrMnSi-HR properties
Typical room-temperature values for 30CrMnSi-HR; 10 are specific to this condition. Other listed values are 30CrMnSi reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
30CrMnSi-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
30CrMnSi-HR has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 850 MPa (123 ksi) — stronger than 67% of steel grades. Elongation at break is 15% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
30CrMnSi-HR is rated for continuous service to 400°C (752 °F). It conducts heat at 37 W/m·K (21.4 BTU/hr·ft·°F), worse than 71% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
30CrMnSi-HR conducts electricity at 7 % IACS, worse than 74% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 30CrMnSi-HR takes about 34 MJ of energy and emits 2.3 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
30CrMnSi-HR's machinability is fair (50/100, worse than 53% of steel grades); weldability fair (40/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 30CrMnSi-HR
Is 30CrMnSi easy to machine?
Rough machine annealed or high-tempered (≤229 HB) with carbide at 100–150 m/min; above 40 HRC use coated carbide/CBN, rigid setups and finish-grind to size.
Can 30CrMnSi be welded?
Weldable but crack-prone: preheat 250–350 °C, low-hydrogen consumables or TIG with matching wire, slow cool and always temper/stress-relieve after welding; avoid welding parts already in the 1600 MPa condition.
Can 30CrMnSi be formed, bent or molded?
Cold form, bend and roll threads only in the annealed condition; hot forge 1150–1200 °C, finish above 900 °C, then slow cool or normalize to prevent flake cracking.
What surface finishes work on 30CrMnSi?
No anodizing — protect with zinc, cadmium or hard-chrome plating, phosphate + oil, black oxide or primer/paint; bake 190–200 °C for 4–24 h after plating high-strength tempers to relieve hydrogen embrittlement.
30CrMnSi 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 |
|---|---|---|
| C | 0.28 – 0.34 | 0.31 |
| Si | 0.9 – 1.2 | 1.05 |
| Mn | 0.8 – 1.1 | 0.95 |
| Cr | 0.8 – 1.1 | 0.95 |
| Niresidual | ≤ 0.3 | — |
| Curesidual | ≤ 0.2 | — |
| Moresidual, not intentionally added | ≤ 0.1 | — |
| P≤0.025 for A-grade (30CrMnSiA) | ≤ 0.03 | — |
| S≤0.025 for A-grade (30CrMnSiA) | ≤ 0.03 | — |
| Fe | balance | — |
30CrMnSi-HR — frequently asked
What is 30CrMnSi-HR used for?
30CrMnSi-HR is typically used for aircraft structural parts, high-strength bolts, shafts and landing gear. In short: high-strength Cr-Mn-Si structural steel; reaches 1600 MPa tempers; crack-sensitive when welded.
What is the yield strength of 30CrMnSi-HR?
30CrMnSi-HR has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 850 MPa (123 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 30CrMnSi-HR easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Rough machine annealed or high-tempered (≤229 HB) with carbide at 100–150 m/min; above 40 HRC use coated carbide/CBN, rigid setups and finish-grind to size.
Can 30CrMnSi-HR be welded?
With care — weldability is rated fair (40/100). Weldable but crack-prone: preheat 250–350 °C, low-hydrogen consumables or TIG with matching wire, slow cool and always temper/stress-relieve after welding; avoid welding parts already in the 1600 MPa condition.
What surface finishes work on 30CrMnSi-HR?
No anodizing — protect with zinc, cadmium or hard-chrome plating, phosphate + oil, black oxide or primer/paint; bake 190–200 °C for 4–24 h after plating high-strength tempers to relieve hydrogen embrittlement.
Can 30CrMnSi-HR be formed, bent or molded?
Cold form, bend and roll threads only in the annealed condition; hot forge 1150–1200 °C, finish above 900 °C, then slow cool or normalize to prevent flake cracking.
What is the maximum service temperature of 30CrMnSi-HR?
30CrMnSi-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 30CrMnSi QT880-520 and 30CrMnSi QT-ISO?
QT880-520 is the default condition — standard commercial Q&T condition — best strength/toughness balance for shafts, gears, high-strength bolts and structural fittings. QT-ISO: choose for thin high-strength parts where distortion and quench cracking must be minimised while keeping toughness at ~1600 MPa. Yield strength is 900 MPa in QT880-520 versus 1,350 MPa in QT-ISO.
Sources
- GOST 4543 Прокат из легированной конструкционной стали (30ХГСА) — Gosstandart (2016)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
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.