Bolts & Nuts News
Contact Us
- Contact Person: Mr.Vincent
- Email:
- info@boltnuts.net
- Chinaboltnuts@gmail.com
- Tel:86-015968936020
Bolts,Nuts,Carriage Bolts,Nuts and Bolts
China Bolt Nut,Hex Bolt,Hex Nut,Threaded Studs,Washers,Hexagon Head Bolt,Bolts and Nuts,Hexagon Socket Bolt,China Structural Bolt,Stud Bolt,Square Head Bolt,Hex Flange Bolt
Heavy Hex Bolt,Heavy Hex Nuts,Structure Nuts,Hexagon Nuts,Hardened Washers,Bolt Nut,Plain Washers,Spring Washers,Flange Nuts,Nylon Nuts,Slotted Nuts,Cap Nuts,THREAD ROD WITH NUTS,Thread Rod,NON-STANDARD BOLTS,Flat Washer,HEXAGON HEAD NUTS,Spring Washer,China kitchen cabinetry
The Ubiquitous A325 (September 6, 2009)
The Ubiquitous A325,ASTM Committee F-16 on Fasteners,A325,bolt,1940s fastener,heavy hex head, high-strength bolts,ASTM developed A325,Committee F-16,Gorman,ubiquitous A325 bolt
"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."
