What Is Angle Steel
Angle steel, also known as angle iron, is a long steel section with two sides perpendicular to each other forming an L-shaped cross section. It is divided into two main types: equal angle steel, with two equal side widths, and unequal angle steel, with different side widths. Unequal angle steel is further divided into equal-thickness and unequal-thickness types.
Specification Representation
Angle steel specifications are expressed by side length and side thickness in millimeters. For example, 30 by 30 by 3 mm denotes an equal angle with 30 mm sides and 3 mm thickness, and the model number can also be given in centimeters of side width, such as 3 angle. The same angle size often has two to seven different thickness options.
Size Classification
Domestic angle steel specifications range from 2 to 20 cm of side length. Angles with side length above 12.5 cm are called large angles, those between 5 and 12.5 cm are medium angles, and those below 5 cm are small angles. This classification guides handling, application, and procurement choices.
Unequal Angle Steel
The cross-sectional height of unequal angle steel is calculated from the long side. Common general specifications range from 50 by 32 mm to 200 by 125 mm with thicknesses from 4 to 18 mm, for example 50 by 32 up to 200 by 125. Unequal angles are rolled by hot rolling mills and serve where one leg carries a different share of the load.
Delivery Lengths and Grades
Delivery lengths are divided into fixed and random lengths. Fixed length ranges for domestic angle steel are 3 to 9 m, 4 to 12 m, 4 to 19 m, and 6 to 19 m depending on specification, while angles produced in Japan are typically 6 to 15 m. Common material grades include Q235B, Q355B, SS400, SM490, S235JR, S275JR, and ASTM A36, with ordering based on the required specification and steel grade.
Applications
Angle steel is used to form various stress members and connections in structures: high-voltage power transmission towers, main beams of steel bridges, tower crane columns and arms, workshop columns and beams, machinery frames, shipbuilding structures, industrial furnaces, reaction towers, container racks, and warehouses. The L-shaped section is efficient in tension, compression, and bracing applications.
Frequently Asked Questions
Q: How is angle steel specified?
A: By side length and side thickness in millimeters, such as 30 by 30 by 3 mm.
Q: What are the main types of angle steel?
A: Equal angle and unequal angle, with equal or unequal thickness variants.
Q: What sizes are considered large angles?
A: Angles with side length above 12.5 cm.
Q: What grades are available?
A: Q235B, Q355B, SS400, S235JR, S275JR, and ASTM A36 among others.
Q: What are angles used for?
A: Transmission towers, bridges, crane structures, frames, and machinery.
Q: What delivery lengths are available?
A: Fixed lengths from 3 to 19 m depending on specification.
Contact us for angle steel stock, custom lengths, drilling and cutting services, and export quotations.