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10/18/2005
Given sufficient tonnage order and lead time, a producing mill will generally produce what a customer orders. The following are some general guidelines that can be used but may vary by regions across Canada.
W-Shapes –
All W-shape sections are imported from mills in the U.S. and overseas.
Most commonly used sections are usually stocked by steel service centres. CISC Steel Service Centre Members are listed in the member directory.
The usual rule is to select the lighter sections in any one grouping (same ‘d’ and ‘b’ dimensions) - Click here for more information.
W-Shapes are commonly rolled to ASTM A992 or A572 grade 50 which are considered to be a suitable substitute for G40.21 350W steel. However, if ASTM A992 is specified, as for seismic application, then A572 grade 50 or G40.21 350W may serve as an appropriate substitution if it meets additional requirements, including the upper limit for yield strength and yield-to-tensile strength ratio as stipulated for A992 steel.
The trend to make ASTM A992 the basic steel grade for rolled shapes in North America is currently underway.
HSS –
Basic grades available in Canada
- 1) G40.21-350W in either Class C or Class H.
Availability of G20.21 350 W Class C dominates over Class H in most regions. Recently Atlas Tube installed a new furnace to expedite the stress-relieve process for production of Class H HSS
- 2) ASTM A500
ASTM A500 Grade C is the common grade but its Fy and Fu are lower than for G40.21-350W HSS. In addition, an HSS section made to ASTM A500 HSS can be and usually is thinner than if made to CSA G40.20/21.
The CISC Handbook has now included column and beam tables for HSS for G40.21 350W Class C and Class H, and for ASTM A500 Grade C.
What is available in your area?
- 1) Assume ASTM A500 unless it is known otherwise that the section used is available in G40.21-350W.
- 2) Where G40.21-350W is available, for example in Ontario and Alberta, assume Class C unless it is known that Class H can be made available in the time frame and quantities desired.
Plate –
Plate to be used for gussets, connections, etc. should be assumed to be CSA G40.21-300W as it is the common grade.
This question appeared in the "Ask Dr. Sylvie" column of Advantage Steel no. 24, Winter 2005.
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