ASTM A335 P9 Seamless Pipe - High Temperature Chrome Moly Alloy Steel Pipes

1. Product Overview: Engineered for Extreme Conditions

ASTM A335 P9 seamless pipe is a chromium-molybdenum alloy steel manufactured for high-temperature/pressure service in corrosive environments. Compliant with ASME B31.3 and NACE MR0175 standards, it delivers exceptional:

• Thermal Stability: Sustained performance at 540-650°C (1000-1200°F)

• Corrosion Resistance: Superior sulfidation/H₂S resistance vs. carbon steel

• Creep Strength: Minimum 30,000 psi yield strength at 600°C

2. Precise Chemical Composition

Table 1: ASTM A335 P9 Chemical Requirements (Weight %)

Trace Control:

• Cu ≤ 0.50% | Ni ≤ 0.40% | V ≤ 0.03%
• Cr:Mo ratio maintained at 9:1 for optimal scale formation

3. Global Equivalent Grades

Table 2: International Standard Cross-Reference

4. Mechanical Properties

Table 3: Minimum Room-Temperature Mechanical Properties (Per ASTM A335)

Elevated-Temperature Performance:

• 540°C (1000°F) Yield Strength: ≥ 165 MPa (24,000 psi)
• Creep Rupture Strength: 34 MPa @ 600°C/100,000 hrs
• Charpy V-Notch Impact: 20J min @ -29°C (-20°F)

5. Key Engineering Advantages

• Oxidation Resistance: Forms protective Cr₂O₃ scale at ≥600°C
• Sulfidation Resistance: 3x longer service life vs. P11 in sour gas
• Thermal Fatigue Resistance: Low expansion coefficient (13.3 μm/m·K)
• Weldability:
  • Pre-heat: 200-300°C
  • Electrodes: E8018-B2 (AWS A5.5)
  • Post-Weld Heat Treat: 675-760°C
• Dimensional Precision:
  • OD Tolerance: ±1% (min ±0.8mm)
  • WT Tolerance: +20%/-12.5%

6. Critical Application Sectors