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30CrMnSiNi2A is a premium low-alloy steel with chromium, manganese, silicon, and nickel, providing superior strength, toughness, and fatigue resistance after quenching and tempering.
It is ideal for automotive drive shafts, high-performance gears, springs, and industrial mechanical components that require durability under extreme loads and cyclic stresses.
Internationally, it is equivalent to SAE 5118 / EN 30CrMnSiNi2A, ensuring compatibility with global industrial and automotive standards.
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Chemical Composition (%)
| Element | Content |
|---|---|
| C | 0.28 – 0.36 |
| Si | 0.17 – 0.37 |
| Mn | 0.50 – 0.80 |
| Cr | 0.80 – 1.10 |
| Ni | 0.30 – 0.50 |
| P | ≤ 0.035 |
| S | ≤ 0.035 |
Mechanical Properties (After Quenching & Tempering)
| Property | Value |
|---|---|
| Tensile Strength | 950 – 1150 MPa |
| Yield Strength | ≥ 750 MPa |
| Elongation | ≥ 12% |
| Hardness (HRC) | 28 – 36 (after tempering) |
Advantages of 30CrMnSiNi2A Alloy Steel
1️⃣ High Tensile and Yield Strength
30CrMnSiNi2A exhibits tensile strength of 950–1150 MPa and yield strength ≥ 750 MPa, making it ideal for high-load shafts, gears, and springs. Its robust mechanical properties allow it to withstand heavy stress and torque in automotive and industrial applications.
2️⃣ Excellent Fatigue Resistance
The addition of nickel (Ni) enhances fatigue resistance, allowing components made from 30CrMnSiNi2A to endure repeated cyclic loading without cracking or permanent deformation. This is critical for drive shafts, torsion bars, and engine components.
3️⃣ Superior Toughness and Impact Resistance
With a carefully balanced chromium, manganese, silicon, and nickel composition, this steel maintains high toughness even after quenching and tempering. Components are less likely to fracture under sudden shocks or high-impact loads, making it suitable for automotive and heavy machinery applications.
4️⃣ High Wear and Abrasion Resistance
30CrMnSiNi2A is wear-resistant due to chromium and nickel, which enhances surface hardness while maintaining core toughness. This makes it ideal for gears, shafts, and mechanical parts that operate under continuous friction and high loads.
5️⃣ Good Hardenability and Heat Treatment Flexibility
Can be quenched and tempered to achieve desired hardness (28–36 HRC)
Heat treatment ensures balanced core strength, surface hardness, and toughness
Suitable for customized mechanical applications depending on the operational load
6️⃣ Machinability and Fabrication Friendliness
Can be machined in annealed condition for precision components
Hardened parts can be finely ground or polished
Weldable with proper preheating and post-weld tempering, making it versatile for complex component assemblies
7️⃣ Wide Industrial Applications
Due to its high-strength, toughness, fatigue resistance, and wear properties, 30CrMnSiNi2A is widely used in:
Automotive: drive shafts, axles, gears, torsion bars
Mechanical engineering: heavy-duty machinery parts, high-load shafts
Industrial: springs, engine components, transmission gears
8️⃣ International Standard Compliance
Meets GB / SAE / EN / ISO standards (SAE 5118 / EN 30CrMnSiNi2A)
Ensures global compatibility, making it ideal for export markets and OEM projects
Heat Treatment Guidelines
Quenching: 830–870°C, oil or water cooling
Tempering: 180–220°C for mechanical parts; higher for wear resistance
Ensures optimal combination of hardness, toughness, and fatigue strength
Applications
Automotive drive shafts and axles
Gears and gear shafts
Springs and torsion bars
Engine and transmission components
High-strength machinery parts requiring fatigue resistance
Physical Properties
| Property | Value |
|---|---|
| Density | 7.85 g/cm³ |
| Melting Point | 1420 – 1460°C |
| Modulus of Elasticity | 210 GPa |
| Thermal Conductivity | 42 W/m·K |
| Coefficient of Thermal Expansion | 12 ×10⁻⁶ /°C |
International Equivalent Standards
| China GB | SAE / AISI | EN / DIN | ISO |
|---|---|---|---|
| 30CrMnSiNi2A | SAE 5118 | 30CrMnSiNi2A | 5118 |
Industry Case Studies
Case 1: Automotive High-Load Shafts
Material: 30CrMnSiNi2A Alloy Steel
Process: Quenched and tempered to HRC 32–36
Benefit: Excellent tensile strength and fatigue resistance under heavy torque
Outcome: Shaft deformation reduced by 25%, service life extended by 30%
Case 2: Industrial Gears
Material: 30CrMnSiNi2A
Process: Hardened and tempered
Benefit: High wear resistance for heavy-duty machinery
Outcome: Gear lifespan increased by 20% compared to 42CrMo4
Case 3: Springs and Torsion Bars
Material: 30CrMnSiNi2A
Process: Heat treated HRC 30–34
Benefit: Superior elasticity and fatigue resistance
Outcome: Reduced maintenance frequency, extended service life
Technical Comparison
| Feature | 30CrMnSiNi2A (SAE 5118) | 30CrMnSiA | 42CrMo4 | Notes |
|---|---|---|---|---|
| Type | Low-alloy steel with Ni | Low-alloy steel | Cr-Mo alloy | Ni increases toughness & fatigue resistance |
| Hardness (HRC) | 28–36 | 28–35 | 28–36 | 30CrMnSiNi2A slightly higher toughness |
| Tensile Strength | 950–1150 MPa | 900–1100 MPa | 980–1200 MPa | Comparable, better fatigue life |
| Yield Strength | ≥ 750 MPa | ≥ 720 MPa | ≥ 740 MPa | Enhanced with Ni content |
| Wear Resistance | High | High | Medium | Optimized for high-load industrial components |
| Applications | Shafts, Gears, Springs | Shafts, Gears, Springs | Shafts, Gears | 30CrMnSiNi2A ideal for automotive & industrial high-fatigue parts |
FAQ – 30CrMnSiNi2A Alloy Steel (SAE 5118 / EN 30CrMnSiNi2A)
1️⃣ What is 30CrMnSiNi2A steel?
30CrMnSiNi2A is a high-strength low-alloy steel containing chromium, manganese, silicon, and nickel. It provides excellent tensile strength, fatigue resistance, toughness, and wear resistance, making it suitable for automotive, mechanical, and industrial applications.
2️⃣ What are the international equivalents of 30CrMnSiNi2A?
SAE / AISI: 5118
EN / DIN: 30CrMnSiNi2A
ISO: 5118
3️⃣ Can 30CrMnSiNi2A be hardened?
Yes. Through quenching and tempering, the steel can reach a hardness of 28–36 HRC, achieving a balance of toughness, strength, and wear resistance suitable for high-load applications.
4️⃣ What are the main applications of 30CrMnSiNi2A?
Automotive drive shafts and axles
Gears and gear shafts
Springs and torsion bars
Engine and transmission components
High-strength industrial machinery parts
5️⃣ Is 30CrMnSiNi2A weldable?
Yes, it is weldable. Preheating is recommended to avoid cracking, and post-weld tempering restores mechanical properties. Suitable welding methods include TIG, MIG, and arc welding.
6️⃣ What is the typical hardness after heat treatment?
Typically 28–36 HRC, depending on quenching and tempering parameters.
Ensures high fatigue resistance, wear resistance, and toughness.
7️⃣ How should 30CrMnSiNi2A be machined?
Best machined in annealed condition for precision parts
Hardened components require sharp tools, appropriate feed rates, and cooling
Can be ground or polished after heat treatment for high-precision mechanical components
8️⃣ What forms are available for 30CrMnSiNi2A?
Round bars, forged bars, plates, sheets, tubes
Shafts, torsion bars, springs, and other precision components
9️⃣ What advantages does 30CrMnSiNi2A have over 30CrMnSiA or 42CrMo4?
Nickel addition improves toughness and fatigue resistance
Balanced surface hardness and core strength
Better suited for high-stress, high-load components
Meets international standards for automotive and industrial applications
1️⃣0️⃣ What industries commonly use 30CrMnSiNi2A steel?
Automotive: high-load shafts, drive axles, gears, springs
Mechanical engineering: heavy-duty machinery parts, precision shafts
Industrial: torsion bars, engine components, transmission gears
Contact Us
For inquiries, technical support, or customized solutions regarding 30CrMnSiNi2A (SAE 5118 / EN 30CrMnSiNi2A) alloy steel products, please contact our professional team. We provide fast response, global shipping, and tailored services to meet your automotive, mechanical, and industrial needs.
Our address
Room 4107, Runfeng Building, Sanqiao New Street, Weiyang District, Xi'an City, Shaanxi Province
Phone Number
+8615769214734
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