QUESTION: (2014) What are the key characteristics of ASTM A1085 HSS as compared to A500 Grade C and CSA G40.20/21 products?

ANSWER: In a nutshell, ASTM A1085 HSS are produced to meet requirements comparable to those of CSA G40.20/21 350WT Category 1. The material is required to conform to a minimum average Charpy V-notch impact value of 25 ft-lb at 40°F (approximately 34 J at 4°C), as represented by the test specimen. In addition, a maximum yield stress at 70 ksi (approximately 485 MPa) as well as a minimum yield stress at 50 ksi (345 MPa) apply. Minimum corner radius control is another measure unique to A1085 square and rectangular HSS. All in all, A1085 HSS are superior to A500 products in various aspects.

QUESTION: (2014) What sectional properties may I use for the design of ASTM A1085 HSS?

ANSWER: Wall-thickness and mass tolerances for ASTM A1085 products are essentially the same as those specified for HSS in CSA G40.20-13. Hence sectional properties provided for CSA G40.20 HSS in the CISC Handbook of Steel Construction, which are calculated from nominal wall thickness, depth, width and diameter, may be used for design. Since A1085 is a new standard, it is not included in Clause 5.1.3 of S16-09; until it is covered, use of A1085 may require Approval in accordance with Clause 5.1.1.

QUESTION: (2014) How do I determine the factored axial compressive resistance of an ASTM A1085 HSS column?

ANSWER:  Since the manufacturing method for A1085 HSS is also permitted for the manufacturing of Class C CSA G40.20 HSS, the factored axial compressive resistance of an A1085 HSS column may be determined in accordance with Clause 13.3.1 with the value of n taken as 1.34. The factored axial compressive resistance tables for Class C G40.20 HSS Columns in the CISC Handbook of Steel Construction may be used provided an adjustment for the small difference in Fy values (345 MPa vs. 350 MPa) is accounted for. Purchasers of A1085 HSS may specify heat treatment, as a Supplemental Requirement S1, which also conforms to the stress-relieve requirement for Class H G40.20 HSS. Hence an n-value of 2.24 may be used for A1085 HSS supplied with Supplemental Requirement S1.
However, use of notch-tough steel as gravity columns is an exception.

QUESTION:  (2014) Are ASTM A1085 products readily available?

ANSWER: ASTM A1085 is a new standard, introduced in 2013. Atlas Tube Canada ULC has started taking orders in 2013. Time will tell if they will be readily available from service centres.