W18x40 Beam Specifications

W18x40 is a rolled structural beam with wide flanges that is used in construction and other applications.

W18x40 Beam Size and Dimensions

The dimensions and specifications of this structural steel beam are below:

Depth	17.9 in
Width	6.02 in
Area	11.8 in2
Weight	40 lb/ft
Web Thickness	0.32 in
Flange Thickness	0.53 in
Area Moment of Inertia	603 in4
Elastic Section Modulus	67 in3

W18x40 Profile

The depth of W18x40 beams may vary by 1/8” above and below the nominal value.

The flange width may vary by 1/4” above nominal and 3/16” below nominal. Flanges may be out of square by as much as 5/16”.

The distance from the center of the web to the center of the profile may be no greater than 3/16”.

The radii of fillets and toes for W-beams are not specified. Instead, these dimensions are left up to individual manufacturers.

W18x40 Weight

Wide flange beams are designated by their depth x weight. The W18x40 designation indicates that the beam weighs 40 pounds per foot. A 10-foot section of W18x40 would weigh 400 pounds and a 50-foot section of W18x40 would weigh 2,000 pounds.

W18x40 Conversion to Metric

The metric equivalent to W18x40 is W460x60. This metric beam has the following specifications:

Depth	455 mm
Width	133 mm
Area	7610 mm2
Weight	60 kg/m
Web Thickness	8 mm
Flange Thickness	13.3 mm

W18x40 Section Properties

W18x40 Area Moment of Inertia

The area moment of inertia (or second moment area) for a W18x40 beam about the x-axis (perpendicular to the flange) can be calculated from the equation below:

The area moment of inertia of the W18x40 profile about the x-axis is approximately 603 in⁴.

W18x40 Section Modulus

The elastic section modulus for a W18x40 beam about the X-axis is calculated from the following equation:

The elastic section modulus for the W18x40 profile about the X-axis is approximately 67 in³.

W18x40 Properties

The properties of W18x40 beams are specified by ASTM A6 “Standard Specifications for Rolled Structural Steel Bars, Plates, Shapes and Sheet Piling”