A709 is a high-strength, low-alloy steel plate that is often used in the manufacturing of bridges. Kloeckner Metals routinely stocks A709 nationwide.

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General Info About A709

Kloeckner Metals offers A709 steel plate in grade 50W. This steel plate is often stocked in the flat-rolled, as-in condition. It is excellent for building bridges and similar applications.

  • Advantages/Disadvantages

    ASTM A709 grade 50 steel plate has good corrosion resistance, low formability for some grades, higher strength, and a higher cost.

  • Industries

    It is used in many industries, primarily in manufacturing and construction.

  • Applications

    If it is properly designed, it can be used for many applications in the unpainted condition including:

    • Pedestrian bridges
    • Railroad bridges and overpasses
    • Highway bridge girders and additional components
  • Machining

    Its machinability is fair. Since it is an alloy steel, it is tougher to machine than plain carbon steel.

  • Welding

    It is weldable by all conventional methods.

  • Heat Treatment

    Heat treatment is not required.

Typical Standards

GradeFormatDimensions (Imperial Units)
50WDiscrete (Mill Rolled)3/16" - 4"72". 84", 96", 120"240" - 480"

Chemical Properties

0.19% Max0.80 - 1.25%0.030% Max0.030% Max0.30 - 0.65%0.40% Max0.40 - 0.65%0.25 - 0.40%0.02 - 0.10%

Mechanical Properties

Tensile Strength485 MPa65 KSI
Yield Strength345 MPa50 KSI
Elongation 200mm/8"1818
Elongation 50mm/2"2121

Frequently Asked Questions

  • What is A709 Steel?


    ASTM A709 is the standard specification for structural steel that is used in bridges. It includes carbon steel plate, HSLA steel plate, and quenched and tempered (Q&T) steel plate, all used as structural steel in the construction of bridges.

  • What is A709 Grade 50W Steel?


    A709 Grade 50W steel is a standard specification for structural steel in bridges with weathering capabilities. With a corrosion index of 6.0 or higher, ASTM A709-50W has substantially better atmosphere corrosion resistance than carbon steels even with the addition of copper.

  • What is HPS Steel?


    HPS stands for “high performance steel” and is a designation given to steels that promise better performance in tensile strength, weldability, cold formability, toughness, and corrosion resistance compared to other mild steel grades. Some HPS steels are interchangeable with the American standard ASTM A709.

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