ASTM A554 TP304 Stainless Steel Welded Mechanical Tubing

ASTM A554 TP304 is welded stainless steel mechanical tubing produced from flat rolled 304 strip. The specification covers tubing for mechanical, structural, ornamental and exhaust service, where a clean appearance, dependable strength and stable corrosion resistance matter more than pressure containment. TP304 is the standard 18 percent chromium and 8 percent nickel austenitic grade, which stays tough at low temperature, is easy to form and weld, and resists attack in most atmospheric and mildly aggressive environments.

What Is ASTM A554 TP304 Tubing?

The tube is roll formed from flat strip and closed with a longitudinal weld made without filler metal, then annealed and finished to the ordered surface condition. Because no filler is added, the wall stays uniform and the bore stays smooth, which suits mechanical, architectural and hygienic duties. Product is offered in round, square, rectangular and special shapes. A554/A554M is the metric version of the same specification, and it also states the marking rules that the finished tube has to carry.

Chemical Composition of Grade 304

Element	Requirement, %
Carbon	0.08 max
Manganese	2.00 max
Phosphorus	0.045 max
Sulfur	0.030 max
Silicon	1.00 max
Chromium	18.0 - 20.0
Nickel	8.0 - 11.0

Mechanical Properties

Property	Value
Heat treatment condition	Solution treated at 1900 °F / 1040 °C
Yield strength	205 MPa / 30 ksi minimum
Tensile strength	515 MPa / 75 ksi minimum
Elongation	35 percent minimum

Physical Properties of TP304 Tube

Property	Value
Density	8000 kg/m3
Elastic modulus	193 GPa
Mean coefficient of thermal expansion, 0 to 100 °C	17.2 µm/m/°C
Mean coefficient of thermal expansion, 0 to 315 °C	17.8 µm/m/°C
Mean coefficient of thermal expansion, 0 to 538 °C	18.4 µm/m/°C
Thermal conductivity at 100 °C	16.2 W/m.K
Thermal conductivity at 500 °C	21.5 W/m.K
Specific heat, 0 to 100 °C	500 J/kg.K
Electrical resistivity	720 nΩ.m

Equivalent Grades for TP304 Tubing

System	Designation
ASTM / ASME	A554 TP304
Euronorm number	1.4301
Euronorm name	X5CrNi18-10
British Standard	304S31
Swedish standard	2332
Japanese Industrial Standards	SUS 304
Chinese standard	06Cr19Ni10

Shapes, Sizes and Finishes

Round tube for mechanical, hydraulic and heat exchanger duties

Square tube for frames, railings, furniture and structural work

Rectangular tube for load bearing frames and cladding supports

Dimensions quoted by outside diameter or side length together with wall thickness

Finishes: mill finish, bright annealed and mirror polished

Supplied in straight lengths, with cut lengths and deeper polishing on request

Quality Control, Marking and Packaging

Raw coil is checked by positive material identification before forming, the longitudinal weld is monitored in process by eddy current and ultrasonic testing, and the finished tube passes a full dimensional inspection. Inspection records and photographs are retained so that every batch stays traceable, and the three level quality control routine keeps the composition and the mechanical performance of each delivery consistent, which simplifies incoming inspection for distributors and fabricators.

Tube is packed in bales or in laminated wooden crates, wrapped in plastic and protected so that it arrives in seaworthy condition, or packed to a specified requirement. Marking follows A554/A554M and identifies the standard, the grade, the dimensions, the heat number and the batch number, together with whether the tube is hot finished or cold finished.

Typical Applications

Food processing equipment and hygienic conveying systems

Pharmaceutical plant piping and equipment frames

Chemical processing and general industrial machinery

Oil and gas instrument and utility tubing

Architecture and construction, including balustrades and handrails

Marine fittings and coastal installations

Heating, ventilation and air conditioning equipment

Water treatment plants and agricultural equipment

Frequently Asked Questions

Q: What is ASTM A554 TP304 tubing used for?
It is welded mechanical tubing for structural, ornamental, mechanical and hygienic applications such as handrails, frames, food equipment, HVAC units and water treatment assemblies.

Q: Is A554 tube welded or seamless?
A554 tube is welded from flat strip with a longitudinal seam made without filler metal, so the wall thickness and the bore remain uniform along the length.

Q: What does TP304 mean?
TP stands for tubular product and 304 is the austenitic grade, containing 18.0 to 20.0 percent chromium and 8.0 to 11.0 percent nickel with carbon limited to 0.08 percent.

Q: What is the difference between ASTM A554 and ASTM A312?
A554 covers welded mechanical tubing for structural and decorative duties without a pressure rating, while A312 covers seamless and welded pipe intended for pressure and high temperature service.

Q: Which shapes and surface finishes are available?
Round, square and rectangular sections in mill finish, bright annealed finish and mirror polished finish, supplied in straight lengths or cut to order.

Q: Which grade is equivalent to A554 TP304 in other systems?
It corresponds to 1.4301 and X5CrNi18-10 in the Euronorm, 304S31 in British Standard, 2332 in the Swedish system, SUS 304 in Japanese Industrial Standards and 06Cr19Ni10 in the Chinese standard.