1. Material Composition & Key Properties
Q: What defines the chemical/mechanical properties of E730K2?
A:
Chemical (wt%):
C: ≤0.20 | Mn: 1.40–2.00 | P: ≤0.015 | S: ≤0.005 | Al: ≥0.025 | Microalloys (V/Nb/Ti): ≤0.20.
Mechanical:
Yield Strength (σᵧ): ≥730 MPa | Tensile (σₜ): 800–950 MPa.
Elongation (A₅): ≥12% | Impact (KV): ≥30J at -60°C (K2 designation).
Note: The "K2" suffix ensures ultra-low-temperature toughness for cryogenic applications.
2. Manufacturing & Standards Compliance
Q: How are E730K2 tubes produced and certified?
A:
Process: Seamless only (hot-rolled + precision cold-drawn with ≤0.05mm OD tolerance).
Heat Treatment: Mandatory Q&T (Quenching at 900–950°C + Tempering at 600–700°C).
Standard Scope: EN 10297-1 for ultra-high-stress applications (e.g., aerospace, deep-sea).
3. Dimensional Tolerances
Q: What are the critical dimensional tolerances?
A:
| Parameter | Tolerance | Criticality |
|---|---|---|
| OD | ±0.6% (min ±0.3 mm) | Ensures interference fits |
| Wall Thickness | ±6% (min ±0.3 mm) | Critical for fatigue/rupture |
| Straightness | ≤0.8 mm/m | Vital for high-speed rotating parts |
4. Applications & Limitations
Q: Where is E730K2 typically used?
A:
Extreme Environments:
Cryogenic storage tanks (-196°C LNG).
Deep-sea mining risers (3,000m+ depth).
High-Tech Industries:
Aircraft landing gear components.
Heavy-duty hydraulic cylinders (1,000+ bar).
Avoid:
Temperatures >650°C (risk of σ-phase embrittlement).
Sour service (H₂S) without ISO 15156-compliant coatings.
5. Quality Validation & Certifications
Q: How is quality assured?
A:
Mandatory Tests:
Tensile (EN ISO 6892-1) | Impact (ISO 148-1 at -60°C).
Hardness (EN ISO 6506-1, max 280 HB).
NDT: 100% phased array UT (EN ISO 10893-11) + TOFD (ISO 10893-10).
Certifications:
EN 10204 3.2 | PED 2014/68/EU (Category IV) | API 6A (wellhead equipment).
