304 Square Tube Strength (Yield & Tensile Guide)

The yield strength of 304 stainless steel square tube is ≥205 MPa, and tensile strength is ≥515 MPa.

In practical applications, high strength indicates that the material is less prone to deformation and breakage (cracking) under static loads; it also typically exhibits good hardness and wear resistance. Therefore, materials requiring high hardness and wear resistance are typically made from high-strength materials. This article introduces the strength standards for 304 stainless steel square tubes.

How much load can a 304 square tube hold?

The load a 304 stainless steel square tube can hold depends on its size, wall thickness, span, and loading conditions, so there is no single fixed value. For example, a 40×40×2.0 mm tube can typically support several hundred kilograms under short-span conditions, but precise capacity should be calculated based on actual design parameters.

How Size and Thickness Affect 304 Square Tube Strength？

The actual strength of 304 square tubes is not only determined by the material itself, but is also significantly influenced by the following factors:

1. Cross-sectional Dimensions (Width & Height)
Larger dimensions result in stronger bending and torsional resistance.
For example, a 40×40 square tube has a much stronger bending resistance than a 20×20 square tube.

2. Wall Thickness
Increasing wall thickness → increasing section modulus → significantly improving strength.

Common thicknesses:
0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.5mm, 2.0mm, 3.0mm…
Increasing the wall thickness from 1.0mm to 2.0mm can increase the bending load-bearing capacity by 50-120%.

3. Weld Quality
304 square tubes are mostly welded tubes, making weld integrity extremely important.
A weld that meets the following criteria has a strength essentially equivalent to the base metal:
Complete fusion of weld metal
No cracks, porosity, or slag inclusions
Sufficient penetration on the back side
Poor welds will directly reduce load-bearing capacity.

304 Stainless Steel Square Tube Standards (ASTM, EN, GB)

The strength standards for 304 square tubes are mainly based on the following specifications:

(1) International Standards (Commonly used for export products)
ASTM A554 (Stainless steel welded structural tubes)
ASTM A312 (Stainless steel seamless tubes)
EN 10296-2 (Stainless steel tubes for structural purposes)
DIN 17455

(2) Chinese National Standards
GB/T 19228.1-2011 "Stainless steel welded tubes"
GB/T 14976 "Stainless steel seamless tubes for fluid transport"

GB/T 12771 "Welded stainless steel tubes for fluid transport"

304 vs 316 Stainless Steel Strength Comparison

In terms of mechanical strength, 316 stainless steel is generally considered stronger than 304 stainless steel. This is also due to the molybdenum element contained in 316 stainless steel. Therefore, 316 stainless steel generally has better mechanical properties. The yield strength and tensile strength of both can vary depending on the manufacturing process and conditions, but overall, the tensile strength of 316 stainless steel is higher than that of 304 stainless steel.

Mechanical properties	304 stainless steel	316 stainless steel
Ultimate Tensile Strength	73200 psi	79800 psi
Tensile Yield Strength	31200 psi	34800 psi
Hardness (Rockwell B)	70	80
Elongation at break	70%	60%

What is the strength of 304 stainless steel square tubes?

The strength of a material is its ability to resist damage under external forces. When a material is subjected to external forces, internal stress is generated. As the external force increases, the stress increases accordingly until the bonding force between the material's internal particles is insufficient to resist the applied external force, at which point the material fails. The ultimate stress value reached at material failure is called the material's ultimate strength.


Tensile strength of 304 stainless steel square tube: ≥515~1035 (MPa). Because tensile strength represents the maximum load-bearing capacity of an actual part under static tensile conditions, and is easy to measure with good reproducibility, it is one of the important mechanical property indicators of metallic materials in engineering, widely used in product specifications or quality control indicators.

Yield strength is the yield limit of a metallic material when it yields, that is, the stress that resists a small amount of plastic deformation. However, for metallic materials without a clear yield point, the stress value that produces 0.2% residual deformation is defined as its yield limit, called the conditional yield limit or yield strength. External forces exceeding this limit will cause permanent, irreversible failure of the component.

For calculation formulas and notes, see “Square Tube Strength Calculation and Notes”.