ASTM A333 Grade 6 — Chemical Composition & Mechanical Properties
ASTM A333 Grade 6 is a low-temperature carbon steel (ltcs) grade for seamless & welded pipe (UNS K03006). It is also known as LTCS. This sheet summarises its chemical composition limits, minimum mechanical properties, heat treatment and typical service. Teshi Group supplies this grade as a stockist and supplier, and manufactures matching flanges and fittings.
ASTM A333 Grade 6 at a glance
| Specification | ASTM A333 Grade 6 |
|---|---|
| Material family | Low-temperature carbon steel (LTCS) |
| Product form | Seamless & welded pipe |
| UNS number | K03006 |
| Also known as | LTCS |
| Document | TG-MG-100 · Rev. 1 · October 2026 |
Typical service
LTCS pipe for −45 °C service — refrigeration, LNG/LPG
Heat treatment
Normalised, or normalised and tempered
Chemical composition of ASTM A333 Grade 6 (weight %)
Single values are maximums unless shown as a range or “min”.
Mechanical properties
| Tensile strength, min | 415 MPa |
|---|---|
| Yield strength (0.2 % offset), min | 240 MPa |
| Elongation, min | 30 % |
| Charpy V-notch test temperature | −45 °C (18 J avg, full size) |
| Hardness | Not specified |
About low-temperature carbon steel (ltcs)
Low-temperature carbon steel (LTCS) is carbon–manganese steel with fine-grain practice and heat treatment chosen to keep its toughness in cold service. Every heat is Charpy impact-tested at the minimum design temperature, which is what separates LTCS from ordinary carbon steel.
Reference information compiled from the published standard for convenience. It does not replace the current edition of the governing standard, which takes precedence. Verify critical dimensions and properties before design, purchase or fabrication. Teshi Engineers & Sales Promoters (P) Ltd accepts no liability for errors or omissions.
International equivalents of ASTM A333 Grade 6
All equivalents| Standard system | Nearest equivalent grade |
|---|---|
| USA — ASTM / ASME | ASTM A333 Grade 6 · ASME SA-333 Grade 6 |
| USA — UNS | K03006 |
| Europe — EN designation | P265NL (EN 10216-4) |
| Europe — W.Nr | 1.0453 |
| Japan — JIS | STPL380 (JIS G3460) |
| China — GB / NB | 16MnDG (GB/T 18984) |
| China — old GB designation | 16MnDG |
| UK — BS (withdrawn) | BS 3603 HFS 430 LT |
Equivalents are the nearest commonly cited grades. Chemistry, mechanical properties and testing differ between standards — compare them before substituting one for another.
Same alloy in other product forms
| Product form | Specification / grade |
|---|---|
| Seamless pipe | ASTM A106 Gr.B |
| Wrought butt-weld fittings | ASTM A234 WPB |
| Wrought butt-weld fittings | ASTM A420 WPL6 |
Other low-temperature carbon steel (ltcs) grades
Low-temperature carbon steel (LTCS) overviewStandards for ASTM A333 Grade 6
All material standardsFAQ
ASTM A333 Grade 6: common questions
What is the minimum yield strength of ASTM A333 Grade 6?
240 MPa, with a minimum tensile strength of 415 MPa.
What is the carbon content of ASTM A333 Grade 6?
0.30 max %.
How is ASTM A333 Grade 6 heat treated?
Normalised, or normalised and tempered.
What is the Chinese (GB) equivalent of ASTM A333 Grade 6?
The nearest Chinese equivalent is 16MnDG (GB/T 18984), formerly 16MnDG. Equivalents are close but not identical — compare chemistry and properties before substituting.
What is the JIS equivalent of ASTM A333 Grade 6?
The nearest Japanese (JIS) equivalent is STPL380 (JIS G3460).
Does Teshi Group supply ASTM A333 Grade 6?
Teshi Group supplies this grade as a stockist and supplier, and manufactures matching flanges and fittings. Send your size, rating and quantity to info@teshigroup.com for a quotation with EN 10204 3.1 certificates.
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