Global Fastener News

9/1/2009
FEATURE

A325 (photo courtesy of Industrial Fasteners Institute).

October 29, 1998 FIN – Editor’s Note: From our FASTENER HISTORY section – The American Society for Testing Materials is marking its 100th anniversary by highlighting its most important standards in a “Heritage Collection.” The ASTM Committee F-16 on fasteners chose ASTM Standard A325 for structural steel bolts for the collection. The following are excerpts from a Standardization News article on the bolt: For more historical articles, visit our FASTENER HISTORY section.

“Every steel building being erected in North America utilizes A325s,” Gene Mitchell, producer vice chair of ASTM Committee F-16 on Fasteners, described the importance of the bolt.

“In the late 1940s fastener producers began to manufacture heavy hex head, high-strength bolts suitable for critical applications such as building and bridge construction,” Maryann Gorman wrote in Standardization News. “It quickly became apparent, as it usually does, that an industry-wide standard was necessary to ensure the quality of these crucial connectors.”

ASTM developed A325 specifying the chemical composition and mechanical properties plus testing and inspection requirements for quenched and tempered structural steel bolts.

The standard “has become an integral part of every steel structure built in the United States, Canada and often in other countries, since the 1950s,” the publication reported.

In addition for use in construction, the flexibility of the A325 makes it useable in heavy equipment and other applications.

Jim Schiele of St. Louis Screw & Bolt recalled the development of the heavy hex head, high-strength bolt and the subsequent testing the fasteners went through at three university research sites in the mid-1950s.

“It’s a real tribute to the standard that since the heavy hex head, high strength bolt was introduced along with the standard in the early 1960s there has not been a single known bridge failure due to bolt failure,” Schiele told Standardization News.

Schiele added that adhering to the standard “has helped make St. Louis Screw & Bolt a better company.”

Committee F-16 shares much of its membership with the Research Council on Structural Connections, the Industrial Fasteners Institute, the American Institute of Steel Construction and the Bolting Technology Council.

Mitchell said revising the minimum tensile strength requirement is the next major change for the committee. Updating the 105 ksi figure would utilize the existing heat treatment technology and bring the requirements for these large A325 bolts in line with ASTM A 490.

“During the ’50s and ’60s, the consistent and uniform through-hardening of large diameter structural bolts was extremely difficult. Today, with the advances in heat treatment technology, the through-hardening process is not the dilemma it once was,” Mitchell added.

Gorman concluded that technology improvements “have provided humans with unprecedented safety in their built environment, and much of this safety is due to the work of committees like F-16 on Fasteners. The next time you drive safely over a sturdy bridge or walk unthinking into your high-rise office building, remember the ubiquitous A325 bolt.” ©1998/2009 Fastener Industry News

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Related Links:

• ASTM