Impact tested seamless and welded pipe to ASTM A333 Grades 1, 3, 4, 6, 7, 8, 9, 10 and 11 for low temperature service down to minus 101 degrees C.
- Standard: ASTM A333, ASME B36.10, ASME B36.19
- Grades: Grade 1, Grade 3, Grade 4, Grade 6, Grade 7, Grade 8, Grade 9, Grade 10, Grade 11
Specifications
| Outer diameter | 1/2" - 48" |
|---|---|
| Wall thickness | SCH 10 - SCH XXS |
| Length | SRL, DRL, 20 FT, 40 FT, or custom |
| Ends | Plain, beveled, threaded |
| Surface treatment | Black painting, varnish, 3PE, FBE, cold insulation |
| Manufacturing process | Seamless and welded |
| Pressure rating | Low temperature and cryogenic service |
Why Low Temperature Pipe Needs Impact Testing
Carbon steel undergoes a ductile to brittle transition as temperature falls. Above the transition temperature the material absorbs energy by deforming plastically; below it, fracture becomes brittle and can propagate catastrophically at low stress. ASTM A333 addresses this by requiring fully killed steel with fine grain practice and controlled chemistry, and by mandating charpy V-notch impact testing at a specified low temperature. The test proves that the material retains notch toughness at the service temperature rather than merely assuming it from room temperature data, which is what separates A333 from ordinary A106 or A53 pipe. Every heat is tested.
Grade Selection by Service Temperature
The A333 grades are matched to service temperature. Grade 1 is carbon steel for service down to minus 45 degrees C. Grade 6, also carbon steel but with a higher manganese and silicon content, is by far the most widely used and covers the same minus 45 degrees C range; it is the usual choice for low temperature carbon steel process piping. Grade 3 is 3.5 percent nickel steel for service down to minus 101 degrees C. Grade 7 is 2.5 percent nickel for minus 73 degrees C service. Grade 8 uses 9 percent nickel for the most severe cryogenic duty down to minus 196 degrees C. Grade 4 is similar to Grade 1 but with restricted chemistry. When specifying, always state both the grade and the required impact test temperature.
What is LTCS pipe and which grade should I use?
LTCS stands for low temperature carbon steel and almost always refers to ASTM A333 Grade 6. It is the standard low temperature carbon steel for process piping down to minus 45 degrees C and is specified by impact testing at that temperature. If your service temperature goes below minus 45 degrees C you need to step up to a nickel steel such as Grade 3 (3.5 Ni, minus 101 C) or Grade 8 (9 Ni, minus 196 C).
What impact test temperature should be specified?
The test temperature should be at or below the minimum design metal temperature of the piping. Common specifications are 0 degrees C, minus 20 degrees C, minus 29 degrees C and minus 45 degrees C. ASTM A333 Grade 6 is normally tested at minus 45 degrees C (minus 50 degrees F). Minimum absorbed energy is typically 18 J average with no single value below 14 J for standard sizes, though project specifications often require higher values such as 27 J. Always state both the temperature and the energy requirement.
Materials
- Carbon steel
- Low alloy steel
- Nickel steel
- Stainless steel
Typical applications
- LNG and cryogenic piping
- Cold climate oil and gas lines
- Refrigeration systems
- Low temperature process piping
- Compressor and gas processing stations
Inspection & testing
- Charpy V-notch impact test at specified temperature
- Ultrasonic testing
- Hydrostatic pressure test
- Tensile and yield testing
- Hardness testing
- Third-party inspection (SGS, BV, TUV)
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