BS 5045 Type A Steel Coil for Gas Cylinders
BS 5045 Type A Steel Coil for Gas Cylinders - Composition, Properties & Equivalents
Comprehensive engineering material data for BS 5045 Type A carbon-manganese steel, used for seamless gas cylinders. Includes chemical composition, mechanical and thermal properties, international equivalents, and application guidance.
Hot forming, deep drawing, spinning, normalizing, normalizing and tempering, welding (on approved procedures), machining
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BS 5045 Type A Steel Coil for Gas Cylinders Introduction
BS 5045 Type A is a carbon-manganese steel grade specified in the United Kingdom standard BS 5045-1 for the manufacture of seamless steel gas cylinders. This grade is designed for the fabrication of transportable pressure vessels through hot forming, deep drawing, or spinning processes followed by normalizing or normalizing and tempering. It provides a favourable combination of strength, ductility, and toughness suitable for the safe containment of compressed and liquefied gases.
- Designed for seamless gas cylinder production with water capacities from 0.5 L to 150 L.
- Offered typically as hot-rolled steel coil in trim edge or mill edge condition.
- Weldable using approved procedures; suitable for cold forming operations prior to heat treatment.
- Meets stringent impact toughness requirements at sub-zero temperatures, ensuring gas cylinder safety during transport and service.
- Widely adopted in Europe and regions following British standards, though gradually being replaced by performance-based EN/ISO designs.
BS 5045 Type A Steel Coil for Gas Cylinders Chemical Composition of BS 5045 Type A Steel
Chemical composition as specified in BS 5045-1:1986 for Type A steel. The steel is fully killed and fine-grained. Residual elements such as Cr, Ni, Mo, Cu are typically controlled to totals not exceeding 0.25% each to maintain weldability and toughness. No intentional additions of microalloying elements are required.
| Element | Content (max, unless range) | Remarks |
|---|---|---|
| Carbon (C) | 0.50 | Maximum content; contributes to strength and hardenability |
| Silicon (Si) | 0.35 | Deoxidizer; higher levels may impair toughness |
| Manganese (Mn) | 1.70 | Principal strengthening and de-sulphurizing element |
| Phosphorus (P) | 0.040 | Maximum limit to avoid embrittlement |
| Sulfur (S) | 0.040 | Maximum limit for ductility and cleanliness |
BS 5045 Type A Steel Coil for Gas Cylinders Physical, Thermal and Electrical Properties of BS 5045 Type A
The following are typical physical properties for a carbon-manganese steel in the normalized condition. They apply to the base material at room temperature unless otherwise stated. These values are suitable for engineering design calculations related to gas cylinders.
| Property | Typical Value | Unit | Measurement Condition / Temperature Range |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20 °C |
| Modulus of elasticity (E) | 200 – 210 | GPa | 20 °C, tension |
| Shear modulus (G) | 79 – 82 | GPa | Calculated from E and ν |
| Poisson's ratio (ν) | 0.29 – 0.30 | – | Elastic range, room temperature |
| Thermal expansion coefficient (α) | 11.5 | 10⁻⁶/K | 20 – 100 °C |
| 12.5 | 10⁻⁶/K | 20 – 200 °C | |
| 13.2 | 10⁻⁶/K | 20 – 300 °C | |
| Thermal conductivity (λ) | 50 – 54 | W/(m·K) | 20 °C |
| Specific heat capacity (cₚ) | 460 – 490 | J/(kg·K) | 20 °C – 100 °C |
| Electrical resistivity (ρₑ) | 0.20 – 0.25 | 10⁻⁶ Ω·m | 20 °C, base material |
BS 5045 Type A Steel Coil for Gas Cylinders Mechanical Properties of BS 5045 Type A
Mechanical properties for finished cylinders manufactured from BS 5045 Type A steel according to BS 5045-1. Test specimens are taken from the cylinder wall in the longitudinal direction. The ratio of yield strength (ReH) to tensile strength (Rm) shall not exceed 0.92. Impact testing is performed at -20 °C using Charpy V-notch specimens.
| Property | Required Value | Unit | Test Condition |
|---|---|---|---|
| Tensile Strength, Rm | 650 – 850 | MPa (N/mm²) | Longitudinal specimen from cylinder wall; 5.65√S₀ gauge length |
| Yield Strength, ReH | ≥ 0.75 × Rm (minimum 490) | MPa | Upper yield or 0.2% proof stress, same specimen |
| Elongation after fracture, A | ≥ 15 | % | Gauge length 5.65√S₀ |
| Bend test | No cracks after 180° bending | – | Bend diameter = 3 × specimen thickness (3t), ambient temperature |
| Impact energy, KV₂ | ≥ 27 | J | Charpy V-notch, -20 °C, longitudinal specimen |
BS 5045 Type A Steel Coil for Gas Cylinders Direct Equivalent Material Standards and Substitutable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| United Kingdom | BS 5045-1 | Type A | Original specification for seamless gas cylinders. |
| – | – | – | No identical international grade exists. Replacement requires full assessment of manufacturing and service requirements. |
BS 5045 Type A Steel Coil for Gas Cylinders Application Introduction
BS 5045 Type A steel is purpose-designed for the production of seamless steel gas cylinders used in the storage and transportation of compressed and liquefied gases. The material's balanced tensile strength and low‑temperature toughness ensure compliance with international transport regulations (ADR, RID, IMDG, etc.). Typical manufacturing involves hot forming of steel coil into a cylinder shape followed by normalizing to achieve the required mechanical properties.
Product Applications: Oxygen gas cylinders (industrial and medical), Nitrogen and argon cylinders, Carbon dioxide (CO₂) cylinders for welding and beverages, Dissolved acetylene cylinders (with porous mass), Compressed Natural Gas (CNG) cylinders for vehicles, Portable fire extinguisher bodies, Scuba diving air tanks (when approved to other standards)
Processed into products: Seamless cylinder body (drawn or spun), Neck ring and valve boss, Cylinder base (foot ring), Welded or integral collar/handle assemblies, Re-processed cylinder halves for smaller pressure reservoirs
Application industries: Industrial Gas Manufacturing, Medical and Healthcare, Fire Protection and Safety, Beverage and Carbonation, Energy and CNG Storage, Laboratories and Specialty Gases
BS 5045 Type A Steel Coil for Gas Cylinders Similar / Substitute Materials for BS 5045 Type A
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| European Union | EN 1964-1 (performance-based) | 34CrMo4 (1.7220) | Common Cr-Mo steel for seamless cylinders; offers higher hardenability and strength but with different chemical composition and heat treatment. Cannot be directly substituted without re-qualification. |
| USA | ASTM A372/A372M | Grade B Class 70 | C-Mn steel for high‑pressure vessels; similar carbon and manganese range. Not specifically for gas cylinders, but may be used as starting material with separate cylinder design approval. |
| Japan | JIS G3429 | STH 22 | Seamless steel tubes for high pressure gas cylinders; lower Mn (≤0.85%) and C (≤0.33%) limits. A possible substitute only after cylinder design and testing in compliance with applicable regulations. |
| International | ISO 9809-1 | Type I (Cylinder design) | Design standard for quenched and tempered Cr-Mo steel cylinders. Material grade is typically 34CrMo4. BS 5045 Type A can sometimes be re-certified to ISO 9809-1 if all performance criteria are met. |
Notes:
- The data are based on BS 5045-1:1986 (Transportable gas containers – Specification for seamless steel gas containers of water capacity 0.5 litres up to and including 150 litres). Where possible, current European or ISO specifications should be consulted for new designs.
- Welding of BS 5045 Type A steel should follow approved procedures; post-weld heat treatment is typically required to restore toughness.
- Cylinder manufacturing must comply with national and international regulations, including periodic testing and certification by notified bodies.
- Type A steel is not intended for sour service (H₂S environments); special requirements apply for hydrogen embrittlement resistance.
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