What an Angle Steel Section Is
An angle steel section is a structural profile with two legs meeting at a right angle, forming an L-shaped cross-section. The shape provides stiffness in two directions and is one of the most economical members for bracing, framing and connection details in steel buildings and industrial structures.
Equal and Unequal Angle Bars
Equal angles have legs of the same length and are used where symmetrical stiffness is needed, such as trusses, frames and brackets. Unequal angles have different leg lengths and suit connections where loading is not symmetric, such as roof purlins and edge members. Standard leg sizes and thicknesses are published in the relevant product standards for direct design use.
Material Grades and Standards
Angle bars are supplied in carbon steel grades to internationally recognized standards. ASTM A36 covers general structural carbon steel for bolted, riveted and welded construction. Q235 is the general structural grade to GB/T 700, and Q345 to GB/T 1591 offers higher strength for heavier loads. SS400 to JIS G3101 is a common equivalent for the same class of service.
ASTM A36 for general structural framing and bracing.
Q235B for building members where moderate strength is sufficient.
Q345 for higher-strength applications and longer spans.
SS400 as a widely used alternative in Asian markets.
Surface Finishes
Angles are normally supplied with a black hot-rolled surface for interior and protected applications. Hot-dip galvanized angles are available for outdoor, coastal and corrosive service, extending the maintenance-free life of the structure significantly.
Applications in Building Structures
Diagonal bracing and wind bracing in steel frames.
Trusses, lattice girders and roof structures.
Brackets, supports and connection details.
Frames for mezzanines, racks and industrial platforms.
Transmission towers and lattice masts.
Frequently Asked Questions
Q: What is the difference between equal and unequal angle steel?
Equal angle steel has two legs of the same length, while unequal angle steel has legs of different lengths for asymmetric loading conditions.
Q: Which standard is used for A36 angle bars?
A36 angle bars are supplied to ASTM A36, with dimensional tolerances normally to ASTM A6.
Q: Can angle bars be galvanized?
Yes, hot-dip galvanizing is available and is recommended for outdoor or corrosive environments.
Q: What size range is commonly available?
Equal and unequal angles are available from small sections around 20 mm legs up to 200 mm legs and larger, depending on the grade.
Q: Are material certificates provided with the delivery?
Yes, mill test certificates with chemical composition and mechanical properties are supplied with each order.