Our MBQ (merchant bar quality) size range varies by mill. You can view and sort our product offerings by mill in the product finder on this page or on NucorNow.

ASTM A36 or ASTM A36M-19 is a specification for carbon structural steel shapes, plates and bars designed for structural quality. These materials are intended for use in the riveted, bolted or welded construction of bridges and buildings, as well as for general structural applications.

Within the category of merchant bar, structural steel is available in various shapes, including angles, channels, rounds, squares and flats. These shapes are utilized for a variety of applications, providing structural support and stability in buildings, bridges and other structures.

A steel angle is a structural steel component with an L-shaped cross-section. It has two legs that form a 90-degree angle. These angles can be equal-leg or unequal-leg (with legs of different lengths). Steel angles are used in construction, engineering and other industries for structural support, corner protection and fastening.

C channels and U channels are both types of steel shapes used for structural support, differing in shape and application. C channels have a “C” shape with a web and two tapered flanges, while U channels have a “U” shape with two parallel flanges and a web. Typically, C channels are stronger and more rigid, making them suitable for heavier loads, while U channels are more versatile for lighter loads and provide edge protection.

The Steel Manufacturers Association defines the types of merchant bar quality (MBQ) products as follows: 

Merchant Bars: Includes all carbon flats, hexes, rounds, squares and special sections that do not meet the definition of SBQ (special bar quality) steel. 

Light Shapes: Includes all carbon and HSLA angles, channels, beams, Ts, Zs and other shapes which have no dimension greater than 3″ and includes shapes which have one or more dimension equal to 3″. 

Structural Angles & Channels: All carbon and HSLA angles & channels with at least one dimension greater than 3″. 

Yes, we domestically manufacture shipbuilding steel grades made through electric arc furnace (EAF) technology to produce low embodied carbon steel. This process ensures a high-quality and consistent supply, supporting the U.S. maritime industry with sustainable and reliable steel solutions.  
 
Nucor manufactures flat bar grade ABS – A (19 mm, .75”), angle bar grade ABS – A (6.4 mm, .25”) and round bar grade ABS – A (20.3 mm, .8”), as well as ABS Grade A and B up to and including 1/2″ thickness, ABS Grade A and AH36 for MBQ up to 1/2″ thickness and ABS Grade A and AH 36 for MBQ up to 1″ thickness. Products and grades vary by mill, so please inquire for your specific needs.