Steel 30CrMnSiNi2A
EN 30CrMnSiNi2A
30CrMnSiNi2A is a silicon-modified Cr-Mn-Ni low-alloy ultra-high-strength steel from the GB aerospace family, functionally equivalent to US 300M, with silicon raising resistance to tempering.
Reference datasheet — 30CrMnSiNi2A 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 QT260 condition
30CrMnSiNi2A tempers and conditions
30CrMnSiNi2A is supplied in 10 conditions, soft to hard. QT260 is the default FabDigit quotes; the values on this page are for it.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
(mill delivery condition for bar/forging stock) | Soft delivery condition for machining, cold straightening and forging stock before final quench and temper. | 560 | 800 | 18 | 217 HB | — |
Cold drawn + annealed bar | Small-diameter precision bar for fasteners and pins, machined then heat treated to final strength. | 720 | 900 | 12 | 25 HRC | 6.4 % IACS |
Normalized + high-temperature temper | Alternative pre-machining condition giving a uniform sorbitic structure and better machined surface than full anneal. | 750 | 950 | 16 | 27 HRC | 6.4 % IACS |
Q&T 500–550 °C | Use when maximum toughness, machinability and reduced SCC/hydrogen sensitivity matter more than peak strength. | 1,150 | 1,280 | 15 | 39 HRC | — |
Isothermal quench (austemper, lower bainite) | Choose for complex thin-section forgings where distortion and quench cracking must be minimised and impact toughness maximised. | 1,300 | 1,550 | 14 | 45 HRC | — |
Q&T 400 °C | Listed for reference only — tempering near 350–450 °C causes a sharp drop in impact energy and should be avoided. | 1,350 | 1,500 | 12 | 44 HRC | 5.9 % IACS |
Q&T 300 °C | Slightly lower strength with improved toughness and hot-strength retention; upper limit before temper embrittlement. | 1,400 | 1,630 | 13 | 46 HRC | — |
QT260Default Q&T 260 °C | Standard aerospace condition — best balance of 1620–1800 MPa strength, ductility and K_IC for landing gear and structural fittings. | 1,450 | 1,700 | 12 | 48 HRC | — |
As-quenched (untempered martensite) | Intermediate condition only — never used in service because untempered martensite is brittle and quench-crack prone. | 1,550 | 2,000 | 5 | 54 HRC | 4.5 % IACS |
Q&T 200 °C | Maximum-strength condition for short-life or stiffness-critical parts where toughness and SCC resistance are less critical. | 1,550 | 1,820 | 10 | 51 HRC | — |
What is 30CrMnSiNi2A?
30CrMnSiNi2A is a silicon-modified Cr-Mn-Ni low-alloy ultra-high-strength steel from the GB aerospace family, functionally equivalent to US 300M, with silicon raising resistance to tempering. Supplied as forgings, bar and plate, it is normally heat treated to about 1450 MPa yield, 1700 MPa tensile, 12% elongation and 48 HRC for landing gear and highly loaded structural forgings. Service is limited to roughly 250 °C, corrosion protection is mandatory, weldability is poor, and machinability is low (score 22); 4335V or 4340 are the nearest alternatives. 30CrMnSiNi2A has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,420°C (2,588 °F). 30CrMnSiNi2A has a yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,700 MPa (247 ksi) — stronger than 97% of steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi).
What is 30CrMnSiNi2A used for?
- landing gear
- aircraft structural forgings
- high-strength shafts
Advantages
- High strength — 1,450 MPa (210 ksi), better than 97% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Difficult to machine — 22/100, worse than 95% of steel grades
- Limited formability — 10/100, worse than 95% of steel grades
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
30CrMnSiNi2A properties
Typical room-temperature values for 30CrMnSiNi2A-QT260; bars are the position among steel grades.
Physical3
30CrMnSiNi2A has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
30CrMnSiNi2A has a yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,700 MPa (247 ksi) — stronger than 97% of steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
30CrMnSiNi2A is rated for continuous service to 250°C (482 °F). It conducts heat at 31 W/m·K (17.9 BTU/hr·ft·°F), worse than 83% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
30CrMnSiNi2A conducts electricity at 5.7 % IACS, worse than 80% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 30CrMnSiNi2A takes about 34 MJ of energy and emits 2.5 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 20%.
Manufacturability7
30CrMnSiNi2A's machinability is poor (22/100, worse than 95% of steel grades); weldability poor (20/100); formability not recommended (10/100).
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. 30CrMnSiNi2A is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 30CrMnSiNi2A
Is 30CrMnSiNi2A easy to machine?
Rough-machine in the annealed condition (HB ≤229); finish cuts on hardened 48 HRC material need rigid setups, coated carbide or CBN, low feeds and generous coolant, leaving stock for grinding.
Can 30CrMnSiNi2A be welded?
Poor weldability — if unavoidable use TIG/EB with matching or low-hydrogen filler, 250–350 °C preheat, and re-quench-and-temper the whole part; never weld in the final heat-treated state.
Can 30CrMnSiNi2A be formed, bent or molded?
Hot forge 1150→900 °C with slow post-forge cooling and immediate anneal; cold forming is limited to gentle straightening in the annealed state.
30CrMnSiNi2A 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 | 0.27 – 0.34 | 0.3 |
| Siraises tempering resistance | 0.9 – 1.2 | 1.05 |
| Mn | 1 – 1.3 | 1.15 |
| Cr | 0.9 – 1.2 | 1.05 |
| Nitoughness and hardenability | 1.4 – 1.8 | 1.6 |
| Curesidual | ≤ 0.2 | |
| Saerospace melt practice, often ≤0.008 | ≤ 0.01 | |
| P | ≤ 0.02 | |
| Fe | balance |
What surface finishes work on 30CrMnSiNi2A?
Shot-peen highly stressed fillets, then cadmium, Zn-Ni or IVD aluminium plate plus primer; bake 190–200 °C for 8–24 h after plating or acid pickling to relieve hydrogen, and avoid grinding burns.
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 30CrMnSiNi2A in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 300M
How much does 30CrMnSiNi2A cost?
30CrMnSiNi2A is a premium-cost steel ($$$), cheaper than about 51% 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.
30CrMnSiNi2A — frequently asked
What is 30CrMnSiNi2A used for?
30CrMnSiNi2A is typically used for landing gear, aircraft structural forgings and high-strength shafts. In short: 300M-class strength level; silicon-modified temper resistance; landing gear workhorse grade.
What is the yield strength of 30CrMnSiNi2A?
30CrMnSiNi2A has a typical yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,700 MPa (247 ksi) — stronger than 97% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 30CrMnSiNi2A easy to machine?
Not especially — machinability is rated poor (22/100, worse than 95% of steel grades). Rough-machine in the annealed condition (HB ≤229); finish cuts on hardened 48 HRC material need rigid setups, coated carbide or CBN, low feeds and generous coolant, leaving stock for grinding.
Can 30CrMnSiNi2A be welded?
Not readily — weldability is rated poor (20/100). Poor weldability — if unavoidable use TIG/EB with matching or low-hydrogen filler, 250–350 °C preheat, and re-quench-and-temper the whole part; never weld in the final heat-treated state.
What surface finishes work on 30CrMnSiNi2A?
Shot-peen highly stressed fillets, then cadmium, Zn-Ni or IVD aluminium plate plus primer; bake 190–200 °C for 8–24 h after plating or acid pickling to relieve hydrogen, and avoid grinding burns.
Can 30CrMnSiNi2A be formed, bent or molded?
Hot forge 1150→900 °C with slow post-forge cooling and immediate anneal; cold forming is limited to gentle straightening in the annealed state.
What is the maximum service temperature of 30CrMnSiNi2A?
30CrMnSiNi2A is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 30CrMnSiNi2A-QT260 and 30CrMnSiNi2A-QT520?
QT260 is the default condition — standard aerospace condition — best balance of 1620–1800 MPa strength, ductility and K_IC for landing gear and structural fittings. QT520: use when maximum toughness, machinability and reduced SCC/hydrogen sensitivity matter more than peak strength. Yield strength is 1,450 MPa in QT260 versus 1,150 MPa in QT520.
How much does 30CrMnSiNi2A cost?
30CrMnSiNi2A is a premium-cost steel ($$$), cheaper than about 51% 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
- GJB / (30CrMnSiNi2A) (1994)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- MMPDS-17 (300M / AMS 6417 comparison data) — Battelle (2022)
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.