Steel 30CrMnSi
GB 30CrMnSi
30CrMnSi is a high-strength Cr-Mn-Si structural alloy steel close to AISI 8630, used where high strength-to-weight is required in aerospace and heavy machine structures.
Reference datasheet — 30CrMnSi 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 QT880-520 condition
30CrMnSi tempers and conditions
30CrMnSi is supplied in 8 conditions, soft to hard. QT880-520 is the default FabDigit quotes; the values on this page are for it.
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 | — |
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?
30CrMnSi is a high-strength Cr-Mn-Si structural alloy steel close to AISI 8630, used where high strength-to-weight is required in aerospace and heavy machine structures. It is supplied hot-rolled, annealed, normalized or cold-drawn as bar, tube and sheet and heat treated to QT880-520, QT880-400 or QT880-250; the default temper gives 900 MPa yield, 1120 MPa tensile, 11 % elongation and 340 HB (36 HRC) with service to 400 °C. Machinability is rated 40, the steel is crack-sensitive in welding and it has no bare corrosion resistance. 30CrMnSiA is the cleaner, aerospace-quality version of the same chemistry. 30CrMnSi 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). 30CrMnSi has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,120 MPa (162 ksi) — stronger than 90% of steel grades. Elongation at break is 11% and the elastic modulus is 205 GPa (29.7 Msi).
What is 30CrMnSi used for?
- aircraft structural parts
- high-strength bolts
- shafts
- landing gear
Advantages
- High strength — 900 MPa (131 ksi), better than 90% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited ductility — 11%, worse than 89% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
- Low fracture toughness — 65 MPa·√m (59.2 ksi·√in), worse than 75% of steel grades
30CrMnSi properties
Typical room-temperature values for 30CrMnSi-QT880-520; bars are the position among steel grades.
Physical3
30CrMnSi 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 has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,120 MPa (162 ksi) — stronger than 90% of steel grades. Elongation at break is 11% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
30CrMnSi 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 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 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's machinability is fair (40/100, worse than 77% of steel grades); weldability fair (40/100); formability poor (25/100).
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. 30CrMnSi is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 30CrMnSi
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.
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 |
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.
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 30CrMnSi in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 8630
How much does 30CrMnSi cost?
30CrMnSi 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.
30CrMnSi — frequently asked
What is 30CrMnSi used for?
30CrMnSi 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?
30CrMnSi has a typical yield strength of 900 MPa (131 ksi) and a tensile strength of 1,120 MPa (162 ksi) — stronger than 90% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 30CrMnSi easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% 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 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?
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 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?
30CrMnSi 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.
How much does 30CrMnSi cost?
30CrMnSi 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
- 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; 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.