HP295 welded gas cylinder steel strip is a special low-carbon microalloyed steel developed for the manufacture of welded gas cylinders, defined in the Chinese standard GB/T 6653 (Steel Plates and Strips for Welded Gas Cylinders). As a core material for gas cylinders closely related to daily life and industrial production, it is widely used in civil LPG cylinders and small low-pressure gas containers because of its balanced mechanical properties, excellent processing performance, and high safety performance.
Designation and Material Concept
The HP in HP295 derives from the Chinese pinyin abbreviation for welded bottle, directly indicating its application field: welded gas cylinders. The number 295 is the minimum yield strength in MPa, the core index of load-bearing capacity. Unlike ordinary carbon steel, HP295 strip uses a low-carbon, low-impurity design with proper microalloying, ensuring the strength required for cylinder use while maintaining good plasticity, toughness, and weldability. It is usually produced by hot rolling, with uniform thickness, smooth surface, and stable internal quality.
Common Thickness and Width Specifications
Per GB/T 6653 and actual application scenarios, the common thickness range is 1.6-12 mm. Strip of 2.0-3.0 mm is mainly used for civil LPG cylinders (2 kg, 5 kg, 15 kg household models), accounting for about 90% of civil cylinder output; 3.0-12 mm strip suits small industrial low-pressure gas cylinders with slightly higher pressure requirements. The common width range is 800-1630 mm; special specifications can be adjusted to 500-2500 mm. Strip 800-1200 mm wide suits small and medium cylinders with diameter below 500 mm, while 1200-1630 mm wide strip is used for large-capacity civil or small industrial cylinders. Thickness tolerance is strictly controlled to ensure uniform cylinder walls and avoid local stress concentration.
Mechanical and Chemical Requirements
Key performance requirements: yield strength at least 295 MPa, tensile strength 440-560 MPa, elongation at least 26% for thickness 3 mm and above (at least 20% for thickness below 3 mm), and a 180° bend test without cracks. Chemical limits: carbon 0.20% max, silicon 0.35% max, manganese 1.50% max (supplier tables vary between 1.00% and 1.50%; confirm against the standard and mill certificate), phosphorus 0.035% max (usually controlled to 0.025% in production), sulfur 0.035% max (usually 0.015%), and acid-soluble aluminum 0.015% min to ensure deoxidation and grain refinement.
Delivery Conditions and Machining Guidance
HP295 strip can be supplied hot-rolled, normalized, tempered, or TMCP plus tempered according to customer needs, and can be shot-blasted and painted to improve corrosion resistance. The delivery condition affects machinability: normalized or tempered strip has better plasticity and toughness and is easier to machine than directly supplied hot-rolled strip.
Strip with tight thickness and width tolerances avoids uneven stress during processing and reduces the risk of deformation. Select stamping speed, welding current, and cutting speed rationally to improve processing efficiency and product quality and reduce tool wear. With the implementation of the new national standard for welded gas cylinders (GB 5842-2023), the performance requirements for HP295 strip have been further tightened, especially the yield ratio, improving safety and reliability.
Applications
HP295 strip is used for civil LPG cylinders, small portable gas cylinders, acetylene cylinders, propane containers, and other products; it is also used in petrochemical and power plant applications for small low-pressure pressure vessels. Typical cylinder specifications include water volumes of 23.5 L, 35.5 L, and 118 L, with an operating pressure of about 2.36 MPa. For higher pressure service, a higher strength grade such as HP345 is required.
Frequently Asked Questions
Q1: What products is HP295 mainly used for?
A1: LPG cylinders, acetylene cylinders, and other welded gas pressure vessels; also small low-pressure containers in petrochemical and power applications.
Q2: Can HP295 be used in high-pressure cylinders?
A2: It suits medium and low-pressure cylinders (design pressure usually up to about 10 MPa); high-pressure cylinders require a higher strength grade such as HP345.
Q3: Can HP295 be used at low temperature?
A3: The typical operating range is about -20°C to 60°C; verify impact toughness for low-temperature service.
Q4: What are the typical cylinder specifications for HP295?
A4: Common water volumes are 23.5 L, 35.5 L, and 118 L, with an operating pressure of about 2.36 MPa.
Q5: Which delivery condition is best for machining?
A5: Normalized or tempered strip has better plasticity and toughness and is easier to machine than hot-rolled strip.
