JIS G3429 Seamless tubes for high pressure gas cylinder

JIS G3429 seamless steel tubes are used for the manufacture of seamless steel gas cylinders specified in JIS B 8230 and JIS B 8241.

JIS G3429 Seamless  tubes for high pressure gas cylinder

Standards: JIS G3429

Size (mm):

The main products of steel / steel grade:

Packing: Bare/bundles/crates/crate protection at the both sides of tubes or as per customers' requirements.

Painting: as requested.

Chemical Compositions(%):
Grade C Si Mn P S Ni Cr Mo
STH11 ≤0.50 0.10-0.35 ≤1.80 ≤0.035 ≤0.035 / / /
STH12 0.30-0.41 0.10-0.35 1.35-1.70 ≤0.030 ≤0.030 / / /
STH21 0.25-0.35 0.15-0.35 0.40-0.90 ≤0.030 ≤0.030 ≤0.25 0.80-1.20 0.15-0.30
STH22 0.33-0.38 0.15-0.35 0.40-0.90 ≤0.030 ≤0.030 ≤0.25 0.80-1.20 0.15-0.30
Tolerance Data
Outside diameter: 1%
Wall thickness: +30%
Wall thickness disparity: Within 20% of the nominal wall thickness
Length: >+30mm

Note: the tolerance is not available for WT<5.6mm tubes

The tubes shall be manufactured by seamless process, electric resistance welding process, or butt welding process, and those of other grades shall be manufactured by seamless process or electric resistance welding process. The tube shall be as manufactured or as cold-finished condition, or they shall be subjected to appropriate heat treatment.

The tubes shall be practically straight. and the two ends shall be at right angles to the axis of the tube.

The tubes shall be free from defects detrimental to practical use.

Seamless steel tubes for high pressure gas cylinder.

This should be marked out in the contract after negotiated by the two parties. The amount of steel tubes shorter than 4000 mm should not exceed five percent of your total number of delivered seamless steel pipe for gas cylinder. The two end surface should be perpendicular to the steel pipe axis. The cutting burrs should be took off.

Standards JIS G3429 standard is typically applicable for gas cylinder steel tubing. We can manufacture the following grade of seamless steel pipe for gas cylinder: 37Mn, 34Mn2V, 30CrMo, 35CrMo, STH11, STH12, STH21, STH22, or anything else.

Manufacturing TechnologyWe adopt hot rolling (hot expanding) or cold rolling (cold drawing) to produce gas cylinder steel replacements.
ApplicationsThis steel tube is mainly appeared to make different associated with gas cylinders, hydraulic cylinders and other high pressure cylinders. Seamless steel pipe for gas cylinder can also be applicable for Gas main Vehicle (NGV) cylinders, Compressed Natural Gas (CNG) trailers, transportation and storage of compressed hydrogen, as well as technical gases, and also scuba diving and fire extinguisher

Specifications of Seamless Steel Pipe for Gas Cylinder

Dimension Deviation

Manufacturing Method Size Range Allowable Outside Diameter Deviation (%) Allowable Wall Thickness Deviation (%)
General Class High Class
Hot Rolling (Hot Expanding) D < 339.7 mm ± 1 + 12.5 - 10 ± 10
D ≥ 339.7 mm + 15 - 12.5 + 12.5 - 10
Cold Rolling (Cold Drawing) Total ± 0.75 ± 10 ± 7.5

Manufacturing Method Size Range Allowable Outside Diameter Deviation (%) Min. Allowable Wall Thickness Deviation (%)
General Class High Class
Hot Rolling (Hot Expanding) D< 339.7 mm ± 1 +25 0 +22.5 0
D ≥ 339.7 mm +30 0 +25 0
Cold Rolling (Cold Drawing) Total ± 0.75 +22.5 0 +15 0


Tech & Service of Seamless pipe

Seamless pipes are extensively applied for the nuclear device, gas, petrochemical, ship building and boiler industries. Seamless pipes dominates 65% of market share in Chinese boiler industry.

How to make seamless pipe(seamless pipe process)?
Hot Piercing Workshop
Piercing process
The cross roll piercing and pilger rolling process in the size range from approx. 250 to 660 mm outside diameter.
Precision cold drawn steel tube production process
Pipe weld cracks
often follow different mechanisms can be divided into two types of thermal cracking and cold cracking.
How to calculate a steel pipe and tube theoretic weight
Calculate a steel pipe?
Pipe fittings are necessary to join together pipes, or to change the direction of an existing pipe.
Pipe beveling
Pipe beveling is the process where an angle is formed between the edge of the end of a pipe or tube and a plane perpendicular to the surface.
Steel pipe cutting machine
Pipe cutting
Cutting tools have a grinding wheel piece cutting machine (also known as toothless saw), hand saw, cutter and other hand tools.
Packing the steel pipes
There are probably hundreds of different methods for packing a pipe, and most of them have merit, but there are two principles that are vital for any method.


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