ASTM A333 Gr.8 Ultra-Low Temperature Steel Pipe

Standard & Grade

• Standard: ASTM A333
• Grade: Gr.8
• Material type: Ultra-low temperature (cryogenic) steel pipe
• Common name: 9% Nickel steel pipe
• Comparable material: AISI 4032 low alloy steel
• Manufacturing process: Seamless or welded (without filler metal)

Applications

• Liquefied Natural Gas (LNG) storage systems
• LNG transportation pipelines
• Cryogenic piping systems
• Ultra-low temperature industrial service

Engineering Characteristics

• Designed for ultra-low temperature service
• Excellent strength and toughness at cryogenic temperatures
• High resistance to thermal stress and strain
• Good weldability and corrosion resistance
• Heat treated to meet cryogenic mechanical requirements

Packing

• Bare packing, bundle packing, or crate packing
• Wooden protection at both ends of pipes
• Sea-worthy export packing as requested
• Each crate marked with order number, heat number, size, weight, and bundle details

Inspection & Testing

• Chemical composition inspection
• Mechanical tests: tensile strength, yield strength, elongation, hardness
• Impact test for cryogenic performance
• Flaring, flattening, and bending tests
• Surface and dimensional inspection
• Non-destructive testing (NDT)
• Hydrostatic test

Surface Treatment

• Oil dip
• Varnish
• Passivation
• Phosphating
• Shot blasting

Chemical Composition (%)

• Carbon (max): 0.13
• Manganese (max): 0.90
• Phosphorus (max): 0.025
• Sulfur (max): 0.025
• Silicon: 0.13 – 0.32
• Nickel: 8.40 – 9.60

Mechanical Properties

• Tensile strength (min): 690 MPa (100,000 psi)
• Yield strength (min): 515 MPa (75,000 psi)

Elongation Requirements (Minimum %)

• 8.0 mm: 22%
• 7.2 mm: 21%
• 6.4 mm: 20%
• 5.6 mm: 18%
• 4.8 mm: 17%
• 4.0 mm: 16%
• 3.2 mm: 15%
• 2.4 mm: 13%
• 1.6 mm: 12%

Mechanical Test Sampling

• Batch heat treatment: testing on 5% of each lot (minimum one pipe)
• Continuous heat treatment: minimum two pipes or 5% of the lot
• Impact test: one set of three specimens from each heat-treatment load