ASTM A333 Grade 9 Pipes

ASTM A333 Grade 9 pipes are seamless or welded steel pipes designed for low temperature service where impact toughness is required below freezing conditions. Amardeep Steel supplies Grade 9 for piping systems operating at temperatures down to −75°C. The grade contains nickel and copper alloying additions that support its low temperature performance. For comparatively moderate low temperature service, see our ASTM A333 Grade 6 pipes, while ASTM A333 Grade 8 pipes are used for more demanding cryogenic applications. Our range of alloy steel pipes and tubes includes additional grades for specialized temperature and pressure requirements.

Each order is supplied with mill test certificates, Charpy impact test results at −75°C and heat number traceability to support material verification and inspection.

What Are ASTM A333 Grade 9 Pipes?

ASTM A333 covers seamless and welded steel pipe for low temperature service and other uses where notch toughness must be proven by test. Grade 9 is one of the alloy grades in the standard. It contains 1.60 to 2.24 percent nickel and 0.75 to 1.25 percent copper, and it is impact tested at minus 75 degrees Celsius (minus 100 degrees Fahrenheit).

Grade 9 also has a higher minimum yield strength than the carbon steel grades, at 315 MPa. That lets it carry the same pressure with a thinner wall, and makes it a practical middle option when Grade 6 is not tough enough at the design temperature and 9 percent nickel steel would be more than the job needs.

How Nickel and Copper Improve Low Temperature Toughness

Nickel lowers the temperature at which steel changes from ductile to brittle behaviour, which is why it appears in almost every steel built for cold service. Copper adds strength and improves resistance to atmospheric corrosion. Combined with a carbon limit of 0.20 percent, this gives a pipe that stays tough at minus 75 degrees Celsius and is still straightforward to weld.

Heat Treatment of ASTM A333 Grade 9 Pipes

Grade 9 pipe is heat treated to control its grain structure using one of the routes allowed by the standard:

• Normalizing: heating to a uniform temperature of at least 815 degrees Celsius and cooling in air, with tempering afterwards if the mill chooses
• Controlled hot finishing (seamless only): reheating and controlling hot working so the finishing temperature falls between 845 and 955 degrees Celsius, then cooling in a controlled atmosphere furnace

Seamless and Welded A333 Grade 9 Pipes

Applications of Nickel Copper Low Temperature Pipes

• LPG, propane and propylene storage and transfer lines
• Ammonia refrigeration and storage systems
• Liquid carbon dioxide lines, including feed lines to CO2 storage tanks
• Cold sections of gas processing and fractionation plants
• Plant piping and pipelines in arctic and cold climate regions

Testing and Documentation

Every order of A333 Grade 9 pipe goes through the checks below at our testing facility or approved third party labs.

• Chemical analysis of heat and product samples
• Tensile test for strength and elongation
• Charpy V-notch impact test at minus 75 degrees Celsius
• Hydrostatic test or nondestructive electric test
• Flattening test, visual inspection and dimensional checks
• Positive material identification and third party inspection on request

Mill test certificates are issued to EN 10204 3.1, with 3.2 available on request. You can view our approvals on the certificates page.

Packing and Marking

Each pipe is marked with the specification, grade, size, schedule, heat number and manufacturer name. Pipe ends are fitted with plastic caps, and lengths are bundled or packed in wooden boxes for export. Read more about our packing and despatch process.