Steel 30CrMnSiA
GB 30CrMnSiA
30CrMnSiA is the low-inclusion, aerospace-quality version of the 30CrMnSi Cr-Mn-Si structural steel, broadly comparable to AISI 4130.
Reference datasheet — 30CrMnSiA 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 QT1080 condition
30CrMnSiA tempers and conditions
30CrMnSiA is supplied in 10 conditions, soft to hard. QT1080 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 |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition — choose for deep machining, cold forming or tube bending before final heat treatment. | 420 | 700 | 20 | 215 HB | — |
Hot rolled | Mill supply condition for bar and plate that will be machined then heat treated by the user. | 480 | 780 | 16 | 23 HRC | 7.5 % IACS |
Stress relieved | Typical delivery state for welded 30CrMnSiA tube frames before final Q&T or for moderate-load weldments. | 500 | 750 | 18 | 21 HRC | 7.5 % IACS |
Normalized | Uniform fine-grain structure for forgings and pre-machining stability before Q&T. | 540 | 830 | 15 | 25 HRC | 7.4 % IACS |
Cold drawn | Close-tolerance bright bar for shafts and fasteners machined without further heat treatment. | 720 | 880 | 10 | 27 HRC | 7.3 % IACS |
Q&T 28–32 HRC (temper ~570 °C) | Tough, machinable condition for shafts and general aerospace hardware where 900–1000 MPa suffices. | 800 | 960 | 16 | 30 HRC | — |
QT1080Default Q&T | Standard GB/T 3077 delivery condition — best balance of 1100 MPa strength and toughness for structural parts. | 930 | 1,130 | 12 | 36 HRC | — |
Q&T 35–40 HRC (temper ~450–500 °C) | Higher-strength Q&T level (~1200 MPa) for landing-gear links, lugs and highly loaded bolts. | 1,080 | 1,230 | 11 | 38 HRC | — |
Q&T high strength | Aerospace high-strength condition for thin-wall welded structures and fittings; toughness and hydrogen-embrittlement margin drop sharply. | 1,350 | 1,560 | 8 | 46 HRC | — |
As-quenched | Intermediate process condition only; must be tempered promptly to avoid quench cracking. | 1,350 | 1,800 | 3 | 51 HRC | 6.5 % IACS |
What is 30CrMnSiA?
30CrMnSiA is the low-inclusion, aerospace-quality version of the 30CrMnSi Cr-Mn-Si structural steel, broadly comparable to AISI 4130. Engineers specify it for high-strength structural parts and fasteners that also need tight cleanliness; it is available as sheet, tube, bar and forging stock in HR, A, N, CD, Q and SR conditions and heat treated from QT1080 to QT1470 or to 28-32 and 35-40 HRC bands. The default temper gives 930 MPa yield, 1130 MPa tensile, 12 % elongation and 340 HB (36 HRC), with 400 °C maximum service and machinability 42. It has no bare corrosion resistance and needs plating plus hydrogen-relief baking above 1000 MPa; 4130 is the nearest widely stocked substitute. 30CrMnSiA 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). 30CrMnSiA has a yield strength of 930 MPa (135 ksi) and a tensile strength of 1,130 MPa (164 ksi) — stronger than 90% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
What is 30CrMnSiA used for?
- aircraft parts
- high-strength fasteners
- landing gear components
Advantages
- High strength — 930 MPa (135 ksi), better than 90% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited ductility — 12%, worse than 84% of steel grades
30CrMnSiA properties
Typical room-temperature values for 30CrMnSiA-QT1080; bars are the position among steel grades.
Physical3
30CrMnSiA 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
30CrMnSiA has a yield strength of 930 MPa (135 ksi) and a tensile strength of 1,130 MPa (164 ksi) — stronger than 90% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
30CrMnSiA is rated for continuous service to 400°C (752 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 69% of steel grades. Thermal expansion is 11.3 µm/m·K (6.28 µin/in·°F).
Electrical3
30CrMnSiA conducts electricity at 7.2 % IACS, worse than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 30CrMnSiA takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
30CrMnSiA's machinability is fair (42/100, worse than 73% of steel grades); weldability good (55/100); formability fair (35/100).
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. 30CrMnSiA is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 30CrMnSiA
Is 30CrMnSiA easy to machine?
Machine in the annealed/normalized state (≈45–60 % of AISI 1212); above 35 HRC use carbide or CBN with rigid setups and reduced feed; leave grinding stock for post-Q&T distortion.
Can 30CrMnSiA be welded?
Good TIG/MIG/resistance weldability up to ~4 mm; preheat 150–300 °C for thick sections, use ER80S-D2/matching filler, and temper or fully re-Q&T after welding to avoid martensitic HAZ cracking.
Can 30CrMnSiA be formed, bent or molded?
Cold bend and roll only in the annealed condition (min bend radius ≈2t); hot forge at 1150–850 °C then normalize; oil quench from 860–890 °C, temper 200–600 °C to the required strength level.
30CrMnSiA 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 | 0.1 |
| Curesidual | ≤ 0.25 | 0.1 |
| Moresidual, not intentionally added | ≤ 0.1 | |
| P'A' high-grade limit | ≤ 0.03 | 0.01 |
| S'A' high-grade limit | ≤ 0.03 | 0.01 |
| Fe | balance |
What surface finishes work on 30CrMnSiA?
No corrosion resistance bare — apply Cd or Zn plating, phosphate + primer, or hard chrome; bake at 190 °C for 8–23 h after plating above 1000 MPa to relieve hydrogen embrittlement; shot peening markedly improves fatigue life.
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 30CrMnSiA in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Other
- 30KhGSA
- Similar grades
- 4130
How much does 30CrMnSiA cost?
30CrMnSiA 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.
30CrMnSiA — frequently asked
What is 30CrMnSiA used for?
30CrMnSiA is typically used for aircraft parts, high-strength fasteners and landing gear components. In short: aerospace-quality 4130 equivalent; weldable up to 4 mm; tempers to 1470 MPa.
What is the yield strength of 30CrMnSiA?
30CrMnSiA has a typical yield strength of 930 MPa (135 ksi) and a tensile strength of 1,130 MPa (164 ksi) — stronger than 90% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 30CrMnSiA easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Machine in the annealed/normalized state (≈45–60 % of AISI 1212); above 35 HRC use carbide or CBN with rigid setups and reduced feed; leave grinding stock for post-Q&T distortion.
Can 30CrMnSiA be welded?
Yes — weldability is rated good (55/100). Good TIG/MIG/resistance weldability up to ~4 mm; preheat 150–300 °C for thick sections, use ER80S-D2/matching filler, and temper or fully re-Q&T after welding to avoid martensitic HAZ cracking.
What surface finishes work on 30CrMnSiA?
No corrosion resistance bare — apply Cd or Zn plating, phosphate + primer, or hard chrome; bake at 190 °C for 8–23 h after plating above 1000 MPa to relieve hydrogen embrittlement; shot peening markedly improves fatigue life.
Can 30CrMnSiA be formed, bent or molded?
Cold bend and roll only in the annealed condition (min bend radius ≈2t); hot forge at 1150–850 °C then normalize; oil quench from 860–890 °C, temper 200–600 °C to the required strength level.
What is the maximum service temperature of 30CrMnSiA?
30CrMnSiA 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 30CrMnSiA-QT1080 and 30CrMnSiA-A?
QT1080 is the default condition — standard GB/T 3077 delivery condition — best balance of 1100 MPa strength and toughness for structural parts. A: softest condition — choose for deep machining, cold forming or tube bending before final heat treatment. Yield strength is 930 MPa in QT1080 versus 420 MPa in A.
How much does 30CrMnSiA cost?
30CrMnSiA 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 (30ХГСА structural alloy steel) — Gosstandart (2016)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- MMPDS-17 (AISI 4130/4135 low-alloy steel chapters, used as analogue) — Battelle/FAA (2022)
- (30CrMnSiA) — Mysteel / 1688 (2025)
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.