hss tubing

The Complete Guide to HSS Tubing


HSS tubing–standing for hollow structural sections–provides economical, high-strength support for construction projects and mechanical applications. Responsible for approximately 18% of the structural steel market, HSS tubing is known for its multidirectional load bearing and comes in a variety of different shapes, including round, square, and rectangular. Stocking HSS tubing throughout our footprint of 40+ North American branches, Kloeckner Metals is proud to supply a complete guide to HSS tubing to our current and future customers.

What does HSS stand for?

HSS tubing refers to a type of steel tubing constructed with a hollow, circular, square, or rectangular cross-section. It is commonly used in construction, engineering, or architectural applications for columns, beams, trusses, or other structural elements. HSS tubing is valued for its strength, durability, and versatility, as well as its aesthetic appeal in certain design contexts.

Download Our Steel Pipe & Steel Tube Spec Sheet Today

Kloeckner Metals is a full-line hss tubing supplier and service center. Download our steel pipe and steel tube spec sheet and check what Kloeckner Metals routinely stocks.

Steel Pipe & Steel Tube Spec Sheet

HSS tube sizes range from 1 inch to 24 inches in diameter, and these size tubes come in various shapes such as round, square, rectangular, oval, and angle. It is typically made from A500 Grade B, but it can also be made from other grades of steel. HSS tubes are often used for structural support in buildings, bridges, and other large constructions, as well as for decorative elements such as railings.

What are the benefits of HSS tube?

Overall, HSS tube offers several advantages over other types of structural elements, making them a popular choice in many industries.

Strength and durability

HSS tubes are made of high-strength steel, which makes them stronger and more durable than other types of tubes. They can withstand heavy loads, harsh weather conditions, and other external factors.

Weight savings

The hollow shape of HSS tubes reduces their weight compared to solid steel sections, making them more cost-effective to transport and easier to handle on the job site.

Design flexibility

HSS tubes are available in a variety of shapes, sizes, and thicknesses, making them versatile and suitable for a wide range of applications. They can be used to create complex shapes and structures, such as arches and trusses.


HSS tubes can be left exposed in buildings, bridges, and other structures, creating an industrial, modern, and aesthetically pleasing look.

Corrosion resistance

HSS tubes can be coated or painted to resist corrosion, ensuring that they have a long service life and require minimal maintenance.

Closed Sections

Enclosed structural sections offer an advantage in their ability to withstand torsional loads. Furthermore, in industries such as food processing and clean facilities where hygiene is paramount, HSS tubes are an optimal choice because their minimal surface area attracts less dust and debris.

Economy of Coatings

HSS tubes with rectangular shapes (including squares) have around 33% less surface area compared to an open section with similar capacity. This translates to reduced surface preparation, less usage of painting materials and labor, and lower requirements for cementitious fireproofing.

What grade of steel is HSS?

HSS is characterized by its high strength-to-weight ratio. The grades used to produce HSS tubing can vary depending on the application, but in general, they are of grades that are durable, formable, and weldable.

A500 Grade B/C

HSS tubes conforming to ASTM A500 B standards are made through a process of cold-forming and welding, utilizing carbon steel to provide essential structural support for various load-bearing applications such as buildings and bridges. A500 Grade B is the most common specification for square, rectangular, and round HSS, and 98% of the time it will also meet the specifications for A500 Grade C.

A513 Type 1

HSS tubes made to ASTM A513 standards are available in various sizes, thicknesses, and shapes and can be produced with different finishes, including bare steel, galvanized steel, or painted.

A36 Grade 50

HSS tubing is also available in A36 Grade 50, which is a hot-rolled form of carbon steel. Due to its versatility, strength, and formability, A36 Grade 50 steel is used in a wide variety of applications.

Deeper dive into A500 Grade B

Since A500 Grade B is one standard in HSS tubing, let’s take a closer look at the chemical composition, mechanical properties, tolerances, maximum twist, and other important details.

Chemical Composition (A500 Grade B)

Carbon Max. % 0.30
Phosphorus Max. % 0.045
Sulphur Max. % 0.045

Mechanical Properties (A500 Grade B)

Tensile strength, min. psi 58,000
Yield strength, min. psi 46,000
Elongation in 2”, min. 23%

Tolerances (A500 Grade B)

Largest Outside Dimension Across Flats, Inches Tolerance for Outside Dimensions Including Convexity or Concavity Wall Thickness Tolerance
1 to 2 ½ incl. Plus or Minus .020” + 10%
Over 2 ½ to 3 ½ incl. Plus or Minus .025” + 10%
Over 3 ½ to 5 ½ incl. Plus or Minus .030” + 10%
Over 5 ½ Plus or Minus 1% + 10%

Maximum Twist (A500 Grade B)

Twist is measured by holding down the edge of one end of a square or rectangular structural hollow on a surface plate with the bottom side of the tube parallel to the surface plate, and noting the height that either corner on the opposite end of the bottom side is above the surface plate.

Longer Outside Dimensions, Inches Maximum Twist Per 8 Ft. of Length, Inches
1 to 1 ½ incl. .050
Over 1 ½ to 2 ½ incl. .062
Over 2 ½ to 4 incl. .075
Over 4 to 5 ½ incl. .087
Over 5 ½ to 8 incl. .100
Over 8 .112

Maximum Outside Corner Radii

For square and rectangular tubing, the radius of any outside corner may not exceed three times the nominal wall thickness.

Squareness of Sides

Adjacent sides of structural hollows may deviate from 90 degrees by plus or minus two degrees, maximum.

Variations from Exact Straightness

Permissible variations include (1/8” * (number of feet of total length/5) including camber and sweep.

What’s important about the different shapes?

HSS tubes are available in various shapes to meet specific construction needs.

Square HSS tube

Square HSS and jumbo tubes are typically available in A513 mechanical tube and A500 structural tube. Square jumbo tubing is suitable for applications requiring uniform geometries across multiple cross-sections.

Round HSS tube

Typically, round HSS tube is available in A513 mechanical tube and A500 structural tube. It is useful in creating uniform shapes, especially for constructing columns, and is highly resistant to torsion.

Rectangular HSS tube

Rectangular jumbo HSS is commonly used in welded steel frames that experience loading from multiple directions. Typically available in both A513 mechanical tube and A500 structural tube, the flat shape of rectangular HSS is ideal for construction and often utilized to create visually pleasing aesthetic effects.

What are standard HSS tube steel sizes?

HSS tube sizes are measured by their outside diameter and wall thickness, which are referred to as the nominal size. HSS tubes come in a wide range of sizes, from small to very large.

Common HSS tube steel sizes are 1/2 inch square to 12 inches square and from .188-inch wall thickness to 0.5-inch wall thickness. When selecting HSS tubes for a project, you must consider the size of the tube as well as the grade of steel.

HSS tubes are also available in square, rectangular, and oval shapes in addition to round tubes. For square, rectangular, and oval tubes, the outside measurements are taken across opposite sides and then averaged to determine the nominal size.

In general, HSS tubes are available in metric sizes as well as imperial sizes. Metric sizes range from 10mm to 600mm with wall thicknesses up to 40mm. The imperial sizes include fractional sizes (1/2” – 4”) and schedule sizes (5” – 24”). But, as a North American metals supplier, our focus here will be on imperial sizes.

It is important to note that the exact size of an HSS tube may vary due to manufacturing tolerances. That is why it is essential to check the actual measurements with your steel service center before buying HSS steel.

HSS steel sizes chart

HSS tubes come in a variety of standard sizes and shapes, which are specified by various standards organizations. The most common standard that specifies HSS sizes is ASTM A500 Grade B. Here are some of the most commonly stocked HSS tube sizes available:

Square Hollow Structural Tubing (ASTM A500 Grade B) at Lengths of 20, 24, and 40 Feet

Size Inches Wall Thickness Gauge Wall Thickness Dec.* Wt. Per Ft. Lbs.
2 3/16 .188 4.32
2 ¼ .250 5.41
2 ½ 3/16 .188 5.59
2 ½ ¼ .250 7.11
3 3/16 .188 6.87
3 ¼ .250 8.81
3 5/16 .312 10.58
3 ½ 3/16 .188 8.15
3 ½ ¼ .250 10.51
4 3/16 .188 9.42
4 ¼ .250 12.21
4 5/16 .312 14.83
4 3/8 .375 17.27
5 3/16 .188 11.97
5 ¼ .250 15.62
5 3/8 .375 22.37
5 ½ .500 28.43
6 3/16 .188 14.53
6 ¼ .250 19.02
6 3/8 .375 27.48
6 ½ .500 35.24
7 3/16 .188 17.08
7 ¼ .250 22.42
8 3/16 .188 19.63
8 ¼ .250 25.82
8 3/8 .375 37.69
8 ½ .500 48.85
10 ¼ .250 32.63
10 3/8 .375 47.90

*Wall thickness may be thinner than theoretical and still be within ASTM standards.

Rectangular Hollow Structural Tubing (ASTM A500 Grade B)

Size Inches Wall Thickness Gauge Wall Thickness Dec.* Wt. Per Ft. Lbs.
3 x 2 3/16 .188 5.59
3 x 2 ¼ .250 7.11
4 x 2 3/16 .188 6.87
4 x 2 ¼ .250 8.8!
4 x 3 3/16 .188 8.15
4 x 3 ¼ .250 10.51
5 x 2 3/16 .188 8.15
5 x 2 ¼ .250 10.51
5 x 3 3/16 .188 9.42
5 x 3 ¼ .250 12.21
5 x 3 3/8 .375 17.27
6 x 2 3/16 .188 9.42
6 x 2 ¼ .250 12.21
6 x 3 3/16 .188 10.70
6 x 3 ¼ .250 13.91
6 x 3 5/16 .312 16.96
6 x 4 3/16 1.88 11.97
6 x 4 ¼ .250 15.62
6 x 4 3/8 .375 22.37
7 x 4 ¼ .250 17.32
7 x 5 3/16 .188 14.53
7 x 5 ¼ .250 19.02
7 x 5 ½ .500 35.24
8 x 2 3/16 .188 11.97
8 x 2 ¼ .250 15.62
8 x 3 3/16 .188 13.25
8 x 3 ¼ .250 17.32
8 x 3 3/8 .375 24.93
8 x 3 ½ .500 31.84
8 x 4 3/16 .188 14.53
8 x 4 ¼ .250 19.02
8 x 4 3/8 .375 27.48
8 x 4 ½ .500 35.24
8 x 6 3/16 .188 17.08
8 x 6 ¼ .250 22.42
8 x 6 3/8 .375 32.58
10 x 2 3/16 .188 14.53
10 x 4 ¼ .250 22.42
10 x 4 3/8 .375 32.58
10 x 6 ¼ .250 25.82
10 x 6 5/16 .312 31.84
10 x 6 3/8 .375 37.69
10 x 6 ½ .500 48.85
10 x 8 ¼ .250 29.23
10 x 8 5/16 .312 36.10
12 x 2 3/16 .188 17.08
12 x 2 ¼ .250 22.42
12 x 4 3/16 .188 19.63
12 x 4 ¼ .250 25.82
12 x 4 5/16 .312 31.84
12 x 4 3/8 .375 37.69
12 x 6 ¼ .250 29.23
12 x 6 3/8 .375 42.79
12 x 6 ½ .500 55.66

*Wall thickness may be thinner than theoretical and still be within ASTM standards.

It’s important to note that the sizes listed above are not an exhaustive list and that other sizes may be available depending on the manufacturer and the specific application. Additionally, HSS tubes are typically available in various wall thicknesses, which can affect the load capacity and rigidity of the tubing.

Where is HSS tube found?

HSS tubes can be found in a wide range of applications. Here are a few examples:

Construction and Heavy Equipment

HSS tubes are commonly used in building construction for various structural components such as columns, beams, and pillars. They provide strength and stability to the structures while also allowing for design flexibility.

Sports Equipment

HSS tubes are used in the construction of sports equipment such as basketball hoops, soccer goals, and fitness equipment due to their strength and durability.


HSS tubes find their way into many types of equipment typical in the agriculture industry including sprayers, tractors, harvesters, combines, and other equipment. They are also found in frames, cranes, greenhouse structures, and roll-over protective structures.

Fabrication & Machining

HSS tubing is typical in bases, spacers, racks, and many machined and welding applications.


HSS tubing is commonly found in solar racking, brackets, and bases.

Oil & Gas

HSS tubing is also common to tooling racks, off-shore production equipment, and off-shore drilling platforms.

Industrial Machinery

HSS tubes are used in industrial machinery for their ability to withstand high loads and pressures. They are often used in the construction of hydraulic cylinders and brackets, spacers, pump bases, machine frames, machine bases, and other structural components.


HSS is commonly used in columns, buildings, towers, signs, and awnings. HSS tubes are also used in bridge construction for their high strength-to-weight ratio and durability. They are often used as bridge girders, trusses, and other structural elements.


HSS tubes are also used in architectural applications for their aesthetic appeal. They can be used in the construction of decorative fencing, gates, or other ornamental structures.

Can you weld HSS steel?

HSS tubes are often welded to through plates or shear end plates to help reinforce structural supports, but two specific rules of welding apply:

  1. Unlike other metals, you cannot weld HSS steel from both sides.
  2. The main member is typically more flexible, creating an uneven load distribution in the welded joint.

When handling HSS steel, welders typically use one of three types of welds: complete‐joint‐penetration (CJP) groove welds, partial‐joint‐penetration (PJP) groove welds, and fillet welds.

How easy is it to fabricate HSS steel?

In addition to providing strength with less weight and easier handling, it is also suitable for many industries and applications due to its ease of fabrication. HSS steel can be formed, cut, punched, flared, flanged, and joined to other shapes through forming, welding, or other mechanical means.

What is the difference between tube steel and HSS?

Structurally, there is no difference between HSS and tube steel (TS). At one point, all tubular steel was simply called tube steel or TS. The American Institute of Steel Construction (AISC) began using HSS in the early 1990s to transition from using TS to using HSS.

This change was intended to create consistency across the global marketplace. In Canada, Asia, and Europe, manufacturers use other terms, including CHS (circular hollow section), SHS (square hollow section), and RHS (rectangular hollow section).

Contact Our Qualified Team Today

Kloeckner Metals is a full-line hss tubing supplier and service center. Kloeckner Metals combines a national footprint with the latest fabrication and processing technologies and most innovative customer service solutions.

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Natalie Spira
Natalie Spira is Kloeckner's Acquisition Marketing Manager. Previously, she was the Founder and CEO of Fraction Marketing, a marketing agency providing fractional support to scaling startups with a focus on acquisition marketing and demand generation. Natalie holds a MBA from Tel Aviv University with concentrations in entrepreneurship and marketing and a BA in English from UCLA.
hss tubing
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