JIS G3116 SG365 High-Strength Steel for Welded Gas Cylinders
JIS G3116 SG365 High-Strength Steel for Welded Gas Cylinders - Complete Material Profile
In-depth technical data for JIS G3116 SG365 steel coil designed for high-pressure gas cylinders. Includes chemical composition, mechanical properties, thermal and electrical physical properties, international equivalents, and application guidelines.
Hot rolling, cold forming, welding, deep drawing, spinning
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JIS G3116 SG365 High-Strength Steel for Welded Gas Cylinders Introduction
JIS G3116 SG365 is a hot-rolled steel coil/plate specifically developed for welded gas cylinders used to store liquefied petroleum gas (LPG), acetylene, and other high-pressure gases. It belongs to the Japanese Industrial Standard G3116 — Steel plates and strips for high pressure gas cylinders. The grade SG365 offers a minimum yield strength of 365 MPa combined with good formability and excellent weldability, ensuring safety and reliability under cyclic pressure loading. Its balanced chemical composition (low carbon, moderate manganese) provides strength without sacrificing toughness, while controlled impurity levels guarantee consistent performance in deep drawing, spinning, and welding operations. Typical delivery condition is hot-rolled, and coils can be supplied in skin-passed or pickled and oiled finish.
JIS G3116 SG365 High-Strength Steel for Welded Gas Cylinders Chemical Composition
The chemical composition of JIS G3116 SG365 is designed to achieve a fine-grained ferritic-pearlitic microstructure that balances strength, toughness, and weldability. Low carbon content ensures good weldability and formability, while manganese provides solid-solution strengthening. Silicon is controlled primarily for deoxidation. Phosphorus and sulfur are kept low to maintain ductility and minimize hot shortness. Values are heat analysis maxima unless otherwise agreed.
| Element | Standard Value (max %) | Remarks |
|---|---|---|
| Carbon (C) | ≤0.20 | Max |
| Silicon (Si) | ≤0.55 | Max |
| Manganese (Mn) | ≤1.60 | Max |
| Phosphorus (P) | ≤0.030 | Max |
| Sulfur (S) | ≤0.030 | Max |
JIS G3116 SG365 High-Strength Steel for Welded Gas Cylinders Thermal and Electrical Physical Properties
The following physical properties are typical for SG365 as a low-carbon manganese steel. These values are obtained from general engineering data for similar structural steels and are valid at room temperature unless otherwise noted. They are not mandatory specification requirements but are useful for design and processing calculations.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20°C |
| Elastic Modulus (E) | 206 | GPa | 20°C |
| Shear Modulus (G) | 79 | GPa | 20°C (calculated) |
| Poisson's Ratio (ν) | 0.3 | – | 20°C |
| Thermal Expansion Coefficient (α) | 11.7 × 10⁻⁶ | K⁻¹ | 0 – 100°C |
| Thermal Conductivity (λ) | 51.9 | W/(m·K) | 20°C |
| Specific Heat Capacity (cp) | 486 | J/(kg·K) | 20°C |
| Electrical Resistivity (ρe) | 0.17 × 10⁻⁶ | Ω·m | 20°C |
JIS G3116 SG365 High-Strength Steel for Welded Gas Cylinders Mechanical Properties
Mechanical tests are performed on test pieces taken in the longitudinal direction as per JIS Z 2241 and JIS Z 2242. The steel demonstrates a minimum yield strength (ReH) of 365 MPa and a tensile strength (Rm) range of 540–740 MPa. For thicknesses up to 16 mm, elongation on a JIS No. 5 test piece is ≥23%; for thicknesses over 16 mm up to 25 mm, ≥22%. Cold bend tests (180°) are carried out without cracking around a former of 1.5 times the specimen thickness. Impact toughness at 0°C averages ≥47 J (single value ≥33 J) on Charpy V-notch specimens. Typical values may exceed specified minima due to modern controlled rolling practices.
| Property | Specified Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥365 | MPa | Thickness ≤25 mm, transverse |
| Tensile Strength (Rm) | 540 – 740 | MPa | Thickness ≤25 mm, transverse |
| Elongation (A) | ≥23 | % | Thickness ≤16 mm, JIS No.5 specimen, longitudinal |
| Elongation (A) | ≥22 | % | Thickness >16 mm ≤25 mm, JIS No.5 specimen, longitudinal |
| Bend Test | No cracks | – | 180° bend, former diameter = 1.5t (t = thickness) |
| Charpy Impact (KV2) | ≥47 (average) | J | 0°C, V-notch, longitudinal |
| Charpy Impact (KV2) | ≥33 (single) | J | 0°C, V-notch, longitudinal |
JIS G3116 SG365 High-Strength Steel for Welded Gas Cylinders Fully Equivalent Standards and Substitutable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3116:2020 | SG365 | Original specification |
| International | ISO 4978:2018 | Grade 4 | Chemically and mechanically identical |
| China | GB/T 6653-2017 | HP365 | Equivalent strength and composition |
| South Korea | KS D 3514:2020 | SG365 | Adopted from JIS standard |
JIS G3116 SG365 High-Strength Steel for Welded Gas Cylinders Application Introduction
JIS G3116 SG365 is the material of choice for most LPG cylinder bodies, both domestic and industrial. Its excellent cold forming characteristics allow deep drawing of seamless cylinder bodies, while its consistent mechanical properties ensure uniform wall thickness and burst resistance. The steel is widely used for welded and brazed gas containers where safety regulations demand reliable toughness at low ambient temperatures.
Product Applications: Domestic LPG cylinders (cooking gas), Industrial acetylene cylinders, CNG storage cylinders for vehicles, Portable fire extinguisher bodies, High-pressure refrigerant containers, Helium and argon gas cylinders
Processed into products: Cylinder bodies (deep-drawn or rolled and welded shells), Head and bottom closures (formed by spinning or stamping), Cylinder necks and valve bosses, Base rings and foot rings, Protective collars
Application industries: Oil & Gas (LPG distribution), Industrial Gas Manufacturing & Distribution, Fire Safety Equipment, Automotive (CNG/LPG tanks), Refrigeration & Air Conditioning (refrigerant cylinders), Medical Gas Supply
JIS G3116 SG365 High-Strength Steel for Welded Gas Cylinders Similar / Alternative Grades for Reference
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10120:2017 | P355NB | Min. yield 355 MPa; tensile 490-630 MPa; similar application but slightly lower strength |
| USA | ASTM A414/A414M | Grade G | Min. yield 345 MPa; tensile 485 MPa; used for pressure vessels; may substitute with proper design |
| Japan | JIS G3116 | SG325 | Lower strength version (yield 325 MPa); suitable for less demanding gas cylinders |
Notes:
Welding and post-weld heat treatment: SG365 can be welded using all common processes (MAG, SAW, TIG) with low-hydrogen procedures. Preheating is generally not required for thicknesses below 25 mm. For severe forming applications, a stress-relief annealing at 580–620°C may be performed to reduce residual stresses. Certification: Coils are usually supplied with inspection certificates according to EN 10204 3.1. Supplementary testing, such as ultrasonic inspection or simulated normalized heat treatment, is available by agreement. Surface condition: The steel may be supplied with mill scale, pickled and oiled, or with a special anti-corrosion coating for extended storage before cylinder fabrication.
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