30CrMnSiA structural steel
OTAI SPECIAL STEEL is 30CrMnSiA steel stockist and supplier from China. more than 25 years of experience in the 30CrMnSiA steel flat bar and plate supply.
30CrMnSiA steel is a high-strength low-alloy structural steel (often classified under the Chinese GB/T 11251 standard) known for its excellent strength, toughness, and wear resistance. It contains chromium, manganese, and silicon as the main alloying elements, and is widely used in the aerospace, military, automotive, and heavy machinery industries.
This steel is ideal for components that demand high fatigue strength, impact resistance, and good weldability after heat treatment.
30CrMnSiA structural steel properties are as follows:
Form of Supply
30CrMnSiA low-alloy structural steel, we can supply the round bar, steel flat bar, plate, hexagonal steel bar, and steel square block. Round bar can be sawn to your required lengths as one-offs or multiple cut pieces. Rectangular pieces can be sawn from flat bar or plate to your specific sizes. Ground tool steel bar can be supplied, providing a quality precision finished bar to tight tolerances.
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- Round
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- sheet
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- Square
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- Plate
Chemical composition
| C(％) | 0.26 – 0.34 | Si(％) | 0.90 – 1.20 | Mn(％) | 0.80 – 1.10 | P(％) | ≤0.030 |
| S(％) | ≤0.030 | Cr(％) | 0.80 – 1.10 |
Mechanical Properties
| Property | Value Range |
|---|---|
| Tensile Strength (Rm) | 980 – 1180 MPa |
| Yield Strength (Rp0.2) | ≥ 835 MPa |
| Elongation (A5) | ≥ 10% |
| Impact Toughness (AKV) | ≥ 63 J |
| Hardness (HBW) | ≤ 229 (annealed) |
After quenching and tempering, 30CrMnSiA achieves excellent strength-to-weight ratio, ideal for lightweight but durable parts.
Heat treatment Related
| Process | Temperature Range | Cooling Method |
|---|---|---|
| Annealing | 820 – 860°C | Furnace cooling |
| Normalizing | 870 – 900°C | Air cooling |
| Hardening | 830 – 860°C | Oil or water quenching |
| Tempering | 500 – 600°C | Air cooling |
For maximum strength and fatigue resistance, the material is usually delivered in quenched and tempered condition (Q+T).
Applications of 30CrMnSiA Steel
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Aircraft landing gear, brackets, and structural frames
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High-strength bolts and fasteners
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Military vehicle armor structures
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Mining and construction machinery parts
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Automotive crankshafts, axles, and suspension arms
Frequently Asked Questions (FAQ)
Q1: What is the difference between 30CrMnSiA and 35CrMo?
A: 30CrMnSiA has better weldability and higher silicon content, offering improved toughness. 35CrMo has slightly higher strength and hardenability.
Q2: Is 30CrMnSiA equivalent to any international grade?
A: It has no direct ASTM equivalent but is roughly similar to AISI 4135 or EN 34CrMo4, with some compositional differences.
Q3: Can 30CrMnSiA be welded?
A: Yes, it has good weldability, but preheating (150–250°C) and post-weld tempering are recommended for structural integrity.
Quality Assured Supply
30CrMnSiA alloy steel is supplied in accordance with our ISO 9001: 2025 registration.
Contact our experienced sales team to help you with your 30CrMnSiA structural steel questions and inquiries by Email or Telephone. The questions will be replied to in 24 hours.
Email: jack@otaisteel.com
Tel: +86-769-23190193
Fax: +86-769-88705839