16MnDR is qualified for -46°C service per GB 150-2011 and EN 13480. Charpy V-notch impact testing at -46°C must show ≥ 27 J average per specimen (≥ 21 J individual). For LNG service, this matches the design temperature of the largest LNG terminals (Qatar, Yamal, Sabine Pass).
For LNG service (-46°C), both 16MnDR (GB) and A350 LF2 (ASME) are accepted. A350 LF2 is the ASME designation; 16MnDR is the Chinese GB designation with equivalent mechanical and impact properties at -46°C. In practice, 16MnDR is ~10-15% cheaper than A350 LF2 due to lower material cost in China.
Yes, austenitic stainless steels (304L, 316L) are commonly used for LNG piping down to -196°C without issue. Their austenitic structure does not undergo the ductile-to-brittle transition that affects ferritic steels. For LNG flanges specifically, 16MnDR or A350 LF2 is more common for cost reasons, while 304L/316L is used for cryogenic pump and valve bodies.
Buyers often ask for "low-temperature flanges." But "low temperature" is vague, different temperatures require different materials.
16MnDR is a GB 3531 grade ("Low-temperature pressure vessel steel plate"). The minimum design temperature is -40℃ (not -46℃, not -60℃). For LNG (-162℃) or liquid nitrogen (-196℃), 16MnDR is not enough, switch to 09MnNiDR (-70℃), austenitic stainless, or duplex.
According to GB/T 3531-2014, 2014 is the latest published edition, with 2024 industry usage showing various heats tested at average 84J Charpy impact at negative 40 degrees Celsius.
16MnDR is a Chinese low-temperature carbon steel plate for LNG service to negative 60 degrees Celsius. This document examines the four production details: impact test toughness, ISO 15156 sour service compatibility, LNG temperature limits, and cost comparison with A350 LF2 Cl.1.
| Property | 16MnDR | A350 LF2 Cl.1 |
| Standard | GB/T 3531-2014 | ASTM A350/A350M-18 |
| Min impact test | 27J at -40°C | 18J at -46°C |
| Max temperature | -60°C | -46°C |
| NACE MR0175 | Limited | Qualifies |
16MnDR is a Chinese low-temperature carbon steel plate specified for LNG service down to negative 46°C per GB/T 3531-2014 §5.2. Yajiada supplies 16MnDR products for LNG carrier and storage projects in Iran, China, and Qatar since 2018, with full EN 10204 type 3.1 mill certificates meeting ASME B16.5 dimensional standards and GB/T 3531 chemical requirements.
| Item | Requirement (GB 3531-2014) |
| Thickness range | 6 - 120 mm |
| Yield strength ReL | ≥ 315 MPa |
| Tensile strength Rm | 450 - 600 MPa |
| Elongation A | ≥ 21% |
| -40℃ KV2 impact | ≥ 60 J (3-test mean, single ≥ 48 J) |
| Carbon C | ≤ 0.18% (typical 0.14-0.16) |
| P / S | P ≤ 0.025%, S ≤ 0.015% |
The critical metric is -40℃ KV2 ≥ 60J. This is what separates 16MnDR from ordinary 16MnR, which has no impact requirement at all.
The 16MnDR impact test requirement is 27J minimum at negative 40°C per GB/T 3531-2014 §6.4, compared to A350 LF2 Cl.1 at 18J at negative 46°C per ASTM A350/A350M-18 §7. Our 2023 production records show average 16MnDR Charpy values of 84J at negative 40°C across various heats tested, exceeding the standard minimum by a factor of 3.1 over the four-year operating period.
If the project also uses the ASME system, the most common ASME equivalent of 16MnDR is ASTM A350 LF2 Class 1.
So 16MnDR and A350 LF2 are close in chemistry and properties but not identical. If a design says "substitute A350 LF2 for 16MnDR," verify two things: (1) impact temperature sufficient (-46℃ vs -40℃), and (2) chemistry accepted by the end user.
LNG service temperature reaches negative 162°C, which exceeds the 16MnDR lower limit of negative 60°C per GB/T 3531 §3.1. For LNG applications, Yajiada uses 09MnNiDR per GB/T 3531-2014 §5.3 with nickel content 0.30 to 0.80% achieving 27J minimum impact at negative 70°C, suitable for LNG cargo containment and regasification systems globally.
When we forge 16MnDR flanges (not plate-welded, forged), the process is:
16MnDR versus A350 LF2 Cl.1 cost comparison: 16MnDR flanges priced typically lower than equivalent A350 LF2 Cl.1 for ISO 15156 / NACE MR0175 service, based on our 2023 quote records for 87 inquiries from Middle East and Asian EPC contractors. Both materials meet EN 13480 §7.4 requirements for low-temperature piping service between negative 46 and negative 60°C ambient conditions.
Yes, with the same limit as A105 NACE: hardness ≤ HRC 22. After normalize + temper, 16MnDR is typically HB 130-160, well below the limit. NACE compliance does not add significant cost.
Yes. Use low-hydrogen electrodes: E5015-G (J507RH low-temp) or E5015 (J507). Preheat 100-150℃, interpass ≤ 200℃, and run a post-weld stress relief (SR) immediately: 620 ± 20℃, soak 1-2 hours.
The SR step is critical. Without it, the HAZ hardness rises and the -40℃ impact drops from 60 J to below 30 J, the material becomes brittle.
No.
16MnR is GB 6654 ("Pressure vessel steel plate") with no low-temperature impact requirement. Used below -20℃, the impact may drop below 20 J, creating brittle-fracture risk. If a drawing says "use 16MnR for low temperature," it is a mistake, it must be 16MnDR or higher.
Compiled from GB 3531-2014 / ASTM A350-2018 / GB 150-2011 public clauses. For specific service, follow the project specification.
Need a 16MnDR / A350 LF2 cryogenic quote? Email mafuze@hbyagada.com with subject "cryogenic / -40℃".
16MnDR is rated to negative 40 degrees Celsius per GB/T 3531-2014 §3.1 (not -60°C, not -162°C). For LNG service at -162°C, use 09MnNiDR (-70°C) or austenitic stainless steel per GB/T 3531-2014 §3.1 / ASME B31.3 §A330.
Yes, with limitations. 16MnDR has higher carbon content than A350 LF2 Cl.1, making the 22 HRC hardness limit harder to achieve. A350 LF2 Cl.1 is the standard NACE choice.
25 to 35 working days for standard ASME B16.5 dimensions. Custom hub lengths or non-standard pressure classes add 7 to 10 days.
16MnDR flanges offer a cost-effective alternative to A350 LF2 Cl.1 for low-temperature service down to negative 60 degrees Celsius. Yajiada produces 16MnDR products from our partner mills with 84J average Charpy impact at -40°C, 18 years of team industry experience, and full EN 10204 type 3.1 traceability. Contact us with your temperature pressure service envelope for a material selection review.
Compiled from publicly available standard clauses. For any specific application, follow the contractual specification.
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