ST45 (CT35)
Characteristics for grade St3sp (Ст3сп)
ST45 Carbon Steel Pipes & Tubes — Trusted Supplier in India | Russian Metals
At Russian Metals, we stock and supply DIN 2391 ST45 seamless precision steel pipes and tubes.
INTRODUCTION OF ST45
ST45 is a medium-carbon alloy steel known for its high tensile strength, excellent toughness, and reliable fatigue performance. Its balanced mechanical properties and moderate corrosion resistance make it suitable for demanding working environments. Because of this, ST45 is widely used in aerospace components, hydraulic systems, chemical processing lines, marine engineering, mechanical structures, and heavy industrial applications.
We also cater to Wacker ST45 specifications for clients requiring specialized processing standards and dimensional accuracy.
ST45 Chemical Composition
| Element | Max (%) | Min (%) |
|---|---|---|
| Carbon (C) | ≤0.21 | – |
| Silicon (Si) | ≤0.35 | – |
| Manganese (Mn) | ≥0.40 | – |
| Phosphorus (P) | ≤0.025 | – |
| Sulfur (S) | ≤0.025 | – |
| Iron (Fe) | Balance | Balance |
What is ST45 Steel?
ST45 (DIN 2391) is a medium carbon, non-alloy precision steel widely used in hydraulic and mechanical systems. It provides:
- High tensile & yield strength for critical load-bearing applications.
- Good machinability and dimensional accuracy for precision engineering.
- Reliable weldability with proper filler materials and controlled heat input.
Its versatility and cost-effectiveness make ST45 a preferred material in many industries.
ST45 Mechanical Properties
| Delivery Condition | Tensile Strength (Rm) | Yield Strength (ReH) | Elongation (A%) |
|---|---|---|---|
| BK (Cold Finished/Hard) | 580 MPa | — | 5% |
| BKW (Cold Finished/Soft) | 520 MPa | — | 8% |
| BKS (Stress Relieved) | 520 MPa | 375 MPa | 12% |
| GBK (Annealed) | 390 MPa | 255 MPa | 21% |
| NBK (Normalized) | 440–570 MPa | 255 MPa | 21% |
Density
~7.85 g/cm³
Hardness
~120–180 HB
Weldability
Good — recommended to use appropriate filler and preheating for high-temp welds.
Applications of ST45 Pipes & Tubes
- Aerospace Systems: Hydraulic & fuel pipelines.
- Mechanical Engineering: Shafts, cylinders, precision components.
- Chemical & Petrochemical Plants: High-pressure piping & heat exchangers.
- Marine & Offshore: Structural pipes and process systems.
- Boilers & Pressure Vessels: Medium pressure and temperature use.
- Industrial Automation: Pneumatic and hydraulic lines.
Available Forms at Russian Metals
- Seamless Precision Tubes: Cold drawn or hot finished, custom cut lengths.
- Round Bars & Hollow Bars: Machining quality for shafts and components.
- Custom Processing: CNC cutting, bending, honing, polishing & coating.
- Surface Conditions: Annealed, normalized (NBK), stress relieved (BKS), polished.
We offer global delivery of ST45 alloy products with MTC compliance for critical projects.
Why Choose Russian Metals for ST45 Steel
- Compliant with DIN 2391 & Wacker ST45 specifications.
- Industrial-grade ST45 with 3.1/3.2 MTC certification.
- Global delivery of ST45 alloy products to aerospace, marine & chemical industries.
- Large stock availability with quick processing & dispatch.
- Custom sizes & finishes to fit complex engineering needs.