ST3
ST3 Carbon Steel — Characteristics, Properties & Supply by Russian Metals
INTRODUCTION OF ST3
ST3 (Russian GOST Ст3) is a widely-used low-carbon structural steel recognized for its high strength, excellent ductility, and smooth weldability. Thanks to its balanced chemical composition, it can be easily machined, bent, drilled, and welded without cracking or loss of mechanical properties. Its cost-effectiveness and dependable performance make it a preferred choice for engineers and fabricators working in civil construction and industrial manufacturing.
Characteristics for grade St3sp ( Ст3сп )
| Grade : | St3sp ( Ст3сп ) |
| Classification : | Normal quality structural carbon steel |
Chemical composition in % for grade 15 ( 15 )
| C | Si | Mn | Ni | S | P | Cr | N | Cu | As |
|---|---|---|---|---|---|---|---|---|---|
| 0.14 - 0.22 | 0.15 - 0.3 | 0.4 - 0.65 | max 0.3 | max 0.05 | max 0.04 | max 0.3 | max 0.008 | max 0.3 | max 0.08 |
ST3 — Chemical Composition
| Element | Min (%) | Max (%) |
|---|---|---|
| C | – | 0.20 |
| Si | – | 0.35 |
| Mn | 0.40 | 0.65 |
| S | – | 0.050 |
| P | – | 0.040 |
| Fe | Balance | Balance |
Mechanical properties under Т=20oС for grade St3sp ( Ст3сп )
| Assortment | Dimension | Direct. | σB | σT | δ5 | ψ | KCU | Heat treatment |
|---|---|---|---|---|---|---|---|---|
| - | (mm) | - | MPa | MPa | % | % | kJ/m² | - |
| Pipe, GOST 8696-74 | 372 | 245 | 23 | |||||
| Pipe, GOST 10705-80 | 372 | 225 | 22 | |||||
| Rolled stock, GOST 535-2005 | 370 - 490 | 205-255 | 23-26 | |||||
| Sheet trick, GOST 14637-89 | 370-480 | 205-245 | 23-26 | |||||
| Rebar, GOST 5781-82 | 373 | 235 | 25 | |||||
| Wire rods , GOST 30136-95 | 490-540 | 60 |
Available Forms & Services — Russian Metals
- Plates & Sheets: Cut-to-size for tanks, machinery, and structures.
- Pipes & Tubes: Seamless & welded, tested and certified.
- Bars & Rods: Round, square, and custom lengths.
- Profiles: Angles, channels, beams for construction frameworks.
- Processing Services: CNC cutting, drilling, welding, bending, and finishing.
We supply industrial-grade ST3 with MTC for reliable performance and complete traceability.
Equivalent & Comparable Grades
EN:
S235JR, S275JR (similar low-carbon structural steels)
ASTM / AISI:
A36 (close mechanical profile)
DIN:
St37-2, St44-2
(Always verify MTCs when substituting for critical projects.)
| Brinell hardness for St3sp ( Ст3сп ) , | HB 10 -1 = 121 MPa
Technological properties for grade St3sp ( Ст3сп )
| Weldability : | without limitations. |
| Flakes : | not predisposed |
| Temper brittleness: | not predisposed |
Physical properties for grade St3sp ( Ст3сп )
| T | E 10-5 | α 10⁶ | λ | ρ | C | R 10⁹ |
|---|---|---|---|---|---|---|
| Grade | MPa | 1/Grade | Watt/(m·Grade) | kg/m3 | J/(kg·Grade) | Ohm·m |
| 20 | 7850 | |||||
| T | E 10 -5 | α 10⁶ | λ | ρ | C | R 10⁹ |
Mechanical & Physical Properties
| Property | Typical Values |
|---|---|
| Yield Strength (σ₀.₂) | ~235–345 MPa |
| Tensile Strength (σᵦ) | ~370–510 MPa |
| Elongation (δ5) | 22–25% |
| Impact Toughness | High even at sub-zero temperatures |
| Density | ~7.85 g/cm³ |
| Hardness | ~130–180 HB |
Weldability
Excellent — welds easily without preheating.
Heat Treatment
Can be normalized or strengthened by controlled rolling.
Why Choose Russian Metals?
- Certified ST3: Full MTC documentation for engineering compliance.
- Large Stock & Fast Delivery: Available across India with quick turnaround times.
- Expert Guidance: Material selection and project-specific advice from experienced professionals.
- Custom Processing: Cutting, machining, and surface finishing available for tailored solutions.
Types of delivery of grade 15 ( 15 )
- B03 - Metal forming treatment. Forgings
- В20 - Classification, nomenclature and general norms
- В22 - Graded and shaped rolling
- B23 - Sheets and Strips
- B24 - Ribbons
- B34 - Ribbons
- B42 - Rails: Pads, Pads, Crutches
- В62 - Steel pipes and connecting parts to them
Advantages of Using ST3 Steel
Key Benefits
- Cost-effective structural steel with high reliability.
- High strength & ductility for demanding applications.
- Good machinability & weldability for fabrication projects.
- Available with MTC certification for engineering compliance.
Applications of ST3 Carbon Steel
Construction & Infrastructure
Used in beams, columns, bridges, and frames.
Pressure Vessels & Storage Tanks
Ideal for fuel, water, and chemical tanks.
Pipeline Systems
Used in oil, gas, and water distribution lines.
Shipbuilding & Marine Equipment
Applied in hulls, deck structures, and supports.
Machinery & Automotive Parts
Used for brackets, plates, and load-bearing elements.
Specification
Mechanical properties :
σB - Tensile strength [MPa]
σT - Yield stress [MPa]
δ5 - Specific elongation at fracture [%]
ψ - Reduction of area [%]
KCU - Impact strength [kJ/m²]
HB - Brinell hardness [MPa]
Physical properties :
T - Test temperature [Grade]
E - Young modulus [MPa]
α - Coefficient of linear expansion (20° - T) [1/Grade]
λ - Thermal (heat) condition coefficient [Watt/(m·Grade)]
ρ - Density [kg/m³]
C - Specific heat (range 20° - T) [J/(kg·Grade)]
R - Electrical resistance [Ohm·m]
Weldability :
without limitations - welding is done without heating and subsequent heat treeting
limited weldability - welding is possible under heating up to 100-120 grade and subsequent heat treeting
hard weldability - obtaining the quality welding needs the additional operations:heating up to 200-300 grade; the heat treeting ia annealing