Structural Steel
– Even though the term “structural steel” is used commonly, there is no accurate definition of this term. Generally it is used to describe steel which is in the form of a bar, plate or a shape produced to a particular specification. The specification involves both chemical and mechanical properties. This particular material is commonly produced to be used in the construction of storage tanks, bridges, buildings and other related structural uses. This material originally was considered to be of low quality but this no longer is the case. The new specifications require the highest degree of steel production. In Canada, the most common material used in producing structural steel is 44w while in other countries A36 is still the most common.

Structural Steels are defined as to size and product shape by common practice in the industry and these definitions are published in present standards. They are:

Plates:

Flat hot rolled steel
a) – Over 7.87” (200mm) in width and over .2362” (6mm) in thickness
b) – Over 47.24” (1200mm) in width and over .177” (4.5mm) in thickness.

Structural Shapes:
Rolled flange sections having at least one dimension of the cross-section 3” (75mm) or greater

Bar Size Shapes:
Rolled flanged sections and angles having a maximum dimension of cross-section less than 3” (75mm)

Bars – Rounds, Squares and Hexagons and all sizes of Flats
Up to 7.87” width and over .1968” thickness

Mild Steel
– The term mild steel really has no meaning. Several years ago people working in the steel industry generally used it to describe A36 material. Use of this term has now carried over to include 44w. It should be noted that when using the term “mild steel” that the person receiving should be working in the same environment. That is to say that there is an understanding that it is representing a particular grade such as A36 or 44W. It should not be confused with 33C which in not intended for any structural end use. It is a safer practice to specify the exact grade as opposed to a term when dealing with structural steel. HSLA (High Strength Low Alloy) has replaced the use of A36 in many market applications.

A36 (38W)
– This is the most popular ASTM structural steel specification for carbon steel shapes, plates and bars, for welded and bolted construction of bridges, buildings and general purposes. It is not recommended where low temperature toughness is important.



44W (300W)
Standard weldable steel normally specified in building construction, it is not recommended where low temperature toughness is important. 44W can be flame cut, formed, drilled welded and machined by all normal means.

50W (350W)
Used normally for HSS sections, where specific strength requirements are required. Suitable for general welded construction where notch toughness at low temperatures is not a design requirement

50A (350A), 50AT (350AT)
are atmospheric corrosion resistant steels normally used in bridge constructions for beams and columns. Type A represents high-strength low-alloy steel with a composition to provide good atmospheric corrosion resistance and good weldability at high-strength levels. Used for both painted and unpainted applications. Steel of this type meet specified strength requirements. Type AT meets Charpy V-Notch impact requirements. The category of steel required must be specified.

ASTM A572-GR50
Intended for the construction of bridges, buildings and other structures. High-strength low-alloy

A516 GRADE 70
used in the construction of boilers and pressure vessels

Weldox 100/130/140/160
are structural steels with a min yield strength of 100/130/140/160 respectively, intended for applications where its high strength permits weight savings to be made. The plate has very good cold bending properties with very good weldability. Fulfills the requirements of ASTM A514, for thickness up to 2 ½”. Guaranteed impact toughness at -40F (-40C).

QT-100 (700QT)
– Quench and Tempered Steel is heat-treated to develop yield strength. This is a cost effective choice for applications which require high strength, improved notch toughness, superior weldability and good forming ability, as well as good resistance to brittle fracture and is suitable for structures where notch toughness at low temperatures are a design requirement. This meets specific strength and Charpy V-notch requirements. The category of steel required must be specified.

QT360 / QT400
– Quench and Tempered Steel that is heat-treated through hardness for resistance to abrasion. Weldable for structural sound joints and can be formed with care.

Hardox 400/500
are abrasion resistant plates with a hardness of 400 HD/500 HD, respectively, intended for applications where demands are imposed on abrasion resistance in combination with impact and/or good cold bending properties. Very good weldability

400F
Used in the original fabrication and repair of heavy equipment subject to severe abrasive wear. Common applications would relate to mining, aggregate, pulp and paper and construction markets.