Jul 26, 2016

ASTM Standards Essential to Structural Steel Tube Production

If you are in the business of producing steel products, you cannot help but be involved with ASTM International standards. Virtually all structural steel products used in construction and manufacturing are produced to an ASTM standard. For example, there are a minimum of 50 ASTM standards referenced in the American Institute of Steel Construction's Specification for Structural Steel Buildings (ANSI/AISC 360), and that doesn't include all the standards used for materials testing during construction. Many manufacturers also use ASTM standards as a basis for production quality when ordering structural steel products used in the products they manufacture. Needless to say, ASTM is part of the vernacular of those involved in the business of structural steel.

Atlas Tube, a division of the JMC Steel Group, is the leading producer of hollow structural sections in North America. Sometimes referred to as structural steel tubes, HSS are used in the design, fabrication and construction of structural steel structures and in the manufacture of agricultural and construction equipment as well as a host of other applications. Atlas also produces straight-seam electric resistance welded pipe piles used as driven piles in foundation design. Atlas Tube has five production facilities located in Harrow, Ontario, Canada; Chicago, Ill.; Plymouth, Mich.; Blytheville, Ark.; and Winnipeg, Manitoba, Canada. Across all these facilities, Atlas produces the largest size range of HSS with the shortest rolling cycles. This situation creates great availability of HSS produced to ASTM standards for the end user. The JMC Steel Group also includes Wheatland Tube, Sharon Tube, Picoma and Energex, which also use ASTM standards in the production of steel pipe and tube products.

HSS are typically produced through a process commonly referred to as the "ERW process." Coils of hot-rolled steel are cut, or slit, into the appropriate width and fed into a tube mill that preps the edges for welding and then uses a series of rolls to cold-work the flat steel into a circular mother tube. Once the flat steel has been shaped into the circular mother tube, the edges are welded together. The weld is an electric-resistance weld and is created using high frequency induction and the natural electrical resistance of steel to heat up the edges of the steel strip. Rollers force the near-molten steel together under great pressure to form a metallurgical bond. As the steel squeezes together and the weld is created, excess steel creates a weld bead both on the inside and the outside of the HSS. The exterior bead is removed so that the exterior has a smooth finish. Once the weld is formed, the HSS is cooled and then passed through a series of squeezing and compression stands that shape the HSS into its final shape and size, whether it be round, square or rectangular. The HSS is then cut to length using a band saw. At this point, the HSS travels to a bundling table where like sizes and lengths are bundled together and then either loaded onto trucks for delivery or put into the warehouse for storage.

While several ASTM standards for pipe and tube production refer to the ERW process of manufacture, the most commonly used standard for the production of HSS is ASTM A500, Specification for Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes. This standard describes the process of manufacture, the process of ordering the finished product and the process of determining the quality of the product. ASTM A500 also describes the requirements for the chemical and mechanical properties of the finished HSS as well as the allowable tolerances in the product and the quality control testing that is required. There are two destructive tests that are required by ASTM A500: the tensile test and the flattening test. Atlas Tube also sometimes does additional destructive tests such as the cone test and the Charpy V-notch method. Testing procedures of steel products are defined in another ASTM standard, A370, Test Methods and Definitions for Mechanical Testing of Steel Products.

Atlas does most of its quality testing in-house so we use the ASTM standards to make sure our testing equipment is adequate and properly maintained to perform the required testing. Atlas does at times employ an outside testing laboratory for testing as well. We make sure that the testing labs that we use also are in compliance with ASTM standards.

Atlas has always viewed the maintenance of ASTM standards as well as the development of new ASTM standards to be a very important process. Atlas Tube has structural engineers and metallurgists on staff that participate in the ASTM committees. Recently, Atlas participated in the development of a new ASTM standard, ASTM A1085, Specification for Cold-Formed Welded Carbon Steel Hollow Structural Sections (HSS) which was published in April 2013. The new ASTM A1085 was developed to improve the level of performance of HSS used in construction, especially those structures that are subject to dynamic and seismic loads. This includes bridges and buildings in earthquake zones. Atlas supported the development of this new standard because it was felt that this was a much-needed improvement to the manufacture of HSS. By participating in the ASTM process, Atlas could foresee and propel the needed changes that the HSS industry should adopt.

ASTM International standards are an integral part of the production of structural steel products. Without them, customers, end users, steel specifiers and manufacturers would not have the common platform on which to base a quality product. ASTM standards clearly are the support that gives structural steel its strength.

Atlas Tube, a division of JMC Steel Group

Brad Fletcher, S.E., is the senior sales engineer at Atlas Tube. In this role, he leverages his 20 years of experience in engineering design and the steel industry to provide technical expertise on the use of steel hollow structural sections and pipe piling products to design engineers, detailers, fabricators and architects. An ASTM International member since 2006, he works on Committee A01 on Steel, Stainless Steel and Related Alloys.

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