1. Material Composition & Key Properties
Q: What defines the chemical and mechanical properties of E355 steel?
A:
Chemical Composition (wt%):
C: ≤0.20 | Mn: 0.90–1.60 | P: ≤0.025 | S: ≤0.020 | Si: ≤0.55.
Mechanical Properties:
Yield Strength (σᵧ): ≥355 MPa | Tensile Strength (σₜ): 490–630 MPa.
Elongation (A₅): ≥18% | Hardness: ≤180 HB.
Note: E355 is a high-strength, fine-grained steel with moderate weldability (Ceq ≤0.47).
2. Manufacturing & Standards Compliance
Q: How are EN 10297-1 E355 tubes produced?
A:
Process: Primarily seamless (hot-rolled or cold-drawn); welded (ERW/SAW) variants require extra testing.
Heat Treatment: Normalizing (900–950°C) or quenching/tempering (for alloyed grades).
Standard Scope: Covers tubes for mechanical, structural, and hydraulic applications.
3. Dimensional Tolerances
Q: What are the critical dimensional tolerances?
A:
| Parameter | Tolerance (EN 10297-1) | Impact |
|---|---|---|
| OD (D) | ±1.0% (min ±0.5 mm) | Ensures fit in assemblies |
| Wall Thickness | ±10% (min ±0.4 mm) | Affects pressure ratings |
| Straightness | ≤1.5 mm/m (cold-drawn: ≤1.0) | Critical for long shafts |
4. Applications & Limitations
Q: Where is E355 typically used?
A:
Heavy Engineering: Hydraulic cylinders, crane jibs, conveyor rollers.
Transportation: Chassis components, trailer axles (cold-drawn).
Avoid:
Temperatures >500°C (risk of decarburization).
Uncoated use in marine/acidic environments.
5. Quality Validation & Certifications
Q: How is quality assured for E355 tubes?
A:
Mandatory Tests:
Tensile (EN ISO 6892-1) | Hardness (EN ISO 6506-1).
Optional Tests:
Ultrasonic (EN 10246-1) | Hydrostatic (EN ISO 10893-4).
Certifications:
EN 10204 3.1/3.2 | PED 2014/68/EU (Category III/IV).
