W8x13 is a lightweight wide-flange H-beam belonging to the American standard series of hot rolled structural sections. The designation W identifies a wide-flange shape, 8 is the nominal depth in inches, and 13 is the nominal weight in pounds per foot, equivalent to about 19.3 kilograms per meter. The section is produced by hot rolling, which gives it consistent mechanical properties, uniform dimensions, and good processing performance. It is widely used in construction and industry as an economical structural member for light-to-medium loads.
Designation and Dimensions
The W8x13 section has a nominal depth of 8 inches, about 203 mm, and a flange width of approximately 4 inches, about 102 mm. The web thickness is about 5.8 mm and the flange thickness about 6.5 mm. The theoretical weight is 19.3 kg per meter. As with all W-shapes, the dimensions and tolerances are governed by ASTM A6, which controls the permissible deviation of depth, flange width, web thickness, flange thickness, and straightness. The cross-sectional design distributes material efficiently between the flanges and the web, giving the beam strong bending resistance in the strong axis and a good balance of stiffness and weight for light framing applications.
Material Grades
W8x13 beams are normally supplied in ASTM A36 or ASTM A992 material. ASTM A36 is a general-purpose carbon structural steel with a minimum yield strength of 36 ksi (250 MPa), excellent weldability, and easy machining, which makes it suitable for applications where moderate strength is sufficient. ASTM A992 is the default specification for wide-flange shapes in North American practice, providing a minimum yield strength of 50 ksi (345 MPa) with controlled carbon equivalent and improved weldability and toughness. The choice between the two depends on the design loads and the applicable building code; for most new steel frames A992 is preferred, while A36 remains common for lighter or less critical members.
Properties and Performance
The W8x13 section combines moderate strength with excellent processing characteristics. Its low-carbon composition gives superior weldability, so the beam can be joined by conventional arc welding processes without special preheat in most cases. It can be cut, drilled, and punched easily, and it accepts standard bolted connections. The section has good bending resistance relative to its weight, adequate torsional stiffness for short-span applications, and predictable behavior under static and light dynamic loading. These properties make it a reliable choice where the design does not demand the higher strength of heavy wide-flange sections.
Typical Applications
W8x13 beams are used in building structures for the beams and columns of factories, warehouses, and low-rise frames, and in mezzanine floors and platforms where a lightweight section with dependable strength is required. In machinery manufacturing they serve as structural supports, equipment bases, and machine frames. Other common uses include port facilities, warehouse racks, walkway supports, and light bridge and infrastructure components. Because the section is compact, it is also convenient for prefabricated steel assemblies and modular structures.
Fabrication and Surface Treatment
The beam can be processed by standard methods: flame or plasma cutting for length adjustment, drilling or punching for connection holes, and welding for field splices and attachments. The hot rolled surface is normally supplied in the black as-rolled condition, and protective treatments such as priming, painting, or hot-dip galvanizing can be applied where the service environment demands corrosion protection. Galvanized beams are suitable for outdoor and high-humidity environments. When ordering, the project specification should state the material grade, dimensions, length, quantity, and any required surface treatment.
Frequently Asked Questions
What does the designation W8x13 mean?
W indicates a wide-flange shape, 8 is the nominal depth in inches, and 13 is the nominal weight in pounds per foot, approximately 19.3 kg per meter.
What are the exact dimensions of W8x13?
The nominal dimensions are about 203 mm depth, 102 mm flange width, 5.8 mm web thickness, and 6.5 mm flange thickness, with tolerances per ASTM A6.
Which material grade is used for W8x13?
It is normally supplied in ASTM A36, with 250 MPa minimum yield strength, or ASTM A992, with 345 MPa minimum yield strength, depending on the design requirements.
Can W8x13 be welded?
Yes. The low-carbon composition gives the beam excellent weldability, and standard arc welding processes can be used without special procedures for most applications.
What is the difference between A36 and A992 for this beam?
A992 provides a higher minimum yield strength of 50 ksi (345 MPa) and is the default for wide-flange shapes, while A36 at 36 ksi (250 MPa) is used where moderate strength is sufficient.
What is W8x13 commonly used for?
It is used for light building frames, mezzanines, platforms, machinery bases, warehouse racks, and other light-to-medium structural applications.
Is galvanized W8x13 available?
Yes. Beams can be hot-dip galvanized or supplied with a primer coat for corrosion protection in outdoor or humid environments.