A36

A36 is a widely used carbon structural steel plate, with its designation conforming to the American Society for Testing and Materials (ASTM) standard ASTM A36/A36M-23 "Standard Specification for Carbon Structural Steel". This standard is the oldest and most extensively used structural steel specification in North America, commonly adopted not only in the United States and Canada but also globally, serving as a recognized benchmark for general-purpose structural steel in international engineering.

The designation "A36" originates from its historical background. The "A" stands for the category of "Ferrous Metals" in the ASTM system, while "36" indicates a minimum yield strength of 36 kilopounds per square inch (ksi), which converts to approximately 250 MPa. This strength level is comparable to internationally used grades such as China's Q235, Europe's S235JR, Japan's SS400 (based on a 400 MPa tensile strength but with a similar yield strength), and Australia's AS3678-250. Falling into the low-to-medium strength category, A36 is suitable for the vast majority of conventional building and engineering structures.

The primary applications of A36 steel plate are extremely broad, mainly used in the fabrication of general building structures, bridges, industrial facilities, machinery, and transportation equipment. Thanks to its reliable performance, mature manufacturing processes, and low cost, A36 has become one of the most fundamental and commonly used structural materials in infrastructure projects across North America and beyond. Typical applications include:

    Construction and Civil Engineering: Beams, columns, trusses, bracing systems, and other load-bearing or non-load-bearing components in factories, warehouses, office buildings, and similar structures.
    Bridge Engineering: Main girders, bridge decks, connectors, and auxiliary structures in small-to-medium-sized bridges.
    Mechanical Manufacturing: Frames, bases, enclosures, conveyor frames, work platforms, and other mechanical parts with moderate strength requirements.
    Transportation: Frames and body structures for ordinary trucks, trailers, agricultural machinery, and rail vehicles.
    General Facilities: Shelves, fences, stairs, walkways, pipe supports, and other municipal or industrial auxiliary installations.

Its main characteristics include:

    Moderate Strength: A minimum yield strength of 250 MPa and a minimum tensile strength exceeding 400 MPa provide good load capacity and structural stability.
    Excellent Weldability and Workability: As a low-carbon steel, A36 has a low carbon equivalent (typically no more than 0.29%), offering outstanding weldability. It can be welded using various methods (e.g., shielded metal arc welding, gas metal arc welding) without requiring preheating or post-weld heat treatment, and is resistant to cracking.
    Good Ductility and Toughness: A36 exhibits high elongation and good room-temperature impact toughness, enabling it to absorb energy and accommodate structural deformation and dynamic loads.
    High Cost-Effectiveness: With mature production processes and low material costs, it is one of the most economical structural steels available.
    Wide Applicability: As a globally recognized "benchmark steel," A36 offers exceptional versatility and interchangeability in design, procurement, and construction.