1. Applicable temperature range
GR1: It is suitable for extremely low temperature environment from -45℃ to -195℃, mainly used in ultra-low temperature scenarios such as liquefied natural gas (LNG).
GR6: The lowest applicable temperature is -45℃, applicable to medium-low temperature environment (such as conventional petrochemical, natural gas transmission)
2. Chemical composition
| element | GR1 | GR6 | Explanation of variances |
|---|---|---|---|
| C | ≤0.30% | ≤0.30% | Similar, but GR6 allows for a higher ceiling |
| Ni | nickel(3.18–3.82%) | No nickel | GR1 improves low-temperature toughness through nickel elements |
| other | No special alloying elements | Containing Cr, Mo, Cu, etc. | GR6 reinforced corrosion resistance and strength |
3. Mechanical properties
| parametric | GR1 | GR6 | Explanation of variances |
|---|---|---|---|
| tensile strength | ≥450 MPa | ≥415 MPa | GR1 has higher strength |
| yield strength | ≥240 MPa | ≥240 MPa | same |
| Low Temperature Impact Toughness | Need to meet the -195 ℃ test requirements | Need to meet the -45 ℃ test requirements | GR1 has tougher toughness requirements |
4. Production process and delivery status
GR1: Normalised (N) or normalised + tempered is required to ensure ultra-low temperature stability.
GR6: Normally delivered in normalised or normalised + tempered condition, and cold working (e.g. cold drawing, cold rolling) is permitted.
5. Areas of application
GR1:
Liquefied natural gas (LNG) storage tanks and transmission pipelines (-195°C grade).
Ultra-low temperature heat exchangers, nuclear energy equipment, etc.
GR6:
Conventional low-temperature pipelines (-45℃ level), such as ethylene, propylene transport.
Cryogenic storage and transport equipment for petrochemical industry (e.g. ammonia, urea production)
