As a leading producer of ST52.4 NBK seamless tubes, we combine advanced metallurgy, cutting-edge manufacturing processes, and rigorous quality control to deliver solutions that exceed global industry standards. In this article, we break down our proprietary production techniques and the competitive advantages that make our tubes the preferred choice for demanding applications in oil & gas, machinery, and automotive industries.
1. Material Selection & Alloy Optimization
Raw Material Precision: We source high-purity billets via electric arc furnace (EAF) melting followed by vacuum degassing (VD) to achieve a carbon content of 0.16–0.22% and manganese content of 1.0–1.3%, ensuring optimal strength-to-ductility balance.
Cleanliness Assurance: Advanced LF refining reduces oxygen levels to ≤20ppm, minimizing impurities that compromise fatigue resistance.
2. Hot Rolling & Cold Drawing Processes
Hot Extrusion Technology: Utilizing 120MN hydraulic presses, we achieve seamless tube forming with wall thickness tolerances of ±5% (ASTM A178-compliant) and outer diameters from Φ25mm to Φ159mm.
Cold Drawing Precision: A 12-stage cold drawing line enhances yield strength to **≥410MPa while maintaining surface roughness below Ra 0.8μm** for friction-sensitive applications.
3. Heat Treatment & Surface Finishing
Controlled Normalization: Inline induction heating (±15°C accuracy) eliminates residual stresses, ensuring dimensional stability during service.
Automated Ultrasonic Testing (UT): Full-body scanning detects surface and subsurface defects (e.g., cracks, lamination) with 99.95% pass rates.
Applications for ST52.4 NBK Tubes
Our tubes excel in:
Oil & Gas: High-pressure boiler tubes (600Bar), CO₂-resistant drilling liners.
Hydraulic Systems: Precision cylinder barrels with roundness ≤0.02mm for extended service life.
Automotive: Turbocharger piping operating at 550°C with minimal thermal expansion.
