ASTM A1065

Specification for Cold-Formed Electric-Fusin (Arc) Welded High-Strength Low-Alloy Structural Tubing in Shapes, with 50ksi Minimum Yield Point

A1065 covers larger rectangular and square HSS shapes that are outside the scope of A500 however, there is some overlap with A500. Per the STI HSS Capability Tool, which shows current availability and producer contact information, the minimum size available is 12-inch x 12-inch. A1065 can also be specified for tapered members. These larger sizes, up to a maximum 200-inch perimeter and 1-inch thickness, are typically used for tall columns or members with long spans or large loading. There are two steel grades available: 50 and 50W. Grade 50W is manufactured with enhanced atmospheric corrosion protection. Both grades have a minimum yield strength of 50ksi; however, the tensile strength for grade 50 is 60ksi compared with 70ksi for grade 50W. Therefore, the supplier cannot substitute one grade for the other without the permission of the purchaser. There is an additional option available in the supplementary requirements for Charpy V-notch testing for use in cyclically loaded structures.

Due to the size of the HSS tubes covered in the A1065 Specification, the tubes are manufactured by first cold-forming two plates into equal-sized C-shapes, which are half of the overall section. These two halves are then welded together with a submerged arc weld (SAW) on both sides to form the final shape. The thickness tolerance for A1065 is much tighter than A500 with a minimum thickness of 0.01 inch less than nominal. Therefore, AISC 360-16 allows cross-sectional properties to be calculated with the full nominal thickness.

Section properties and design tables are available for A500, A1065 and A1085 in STI Design Guide Volume 1 and 2A and 2B.

For more information on this and other HSS ASTM standards, see our HSS Insider article “Understanding HSS Material Specifications: Which ASTM Should I Specify for HSS?“