Fastener Technology International - December 2007/January 2008 - (Page 80)

The Bolt Doctor by: Guy Avellon GT Technical Consultants 271 Sandy Point Lane Lake Zurich, IL 60047 USA Office: +1 847 438 8529 Fax: +1 847 438 8539 Cell: +1 847 477 5057 www.BoltDoc.com Terminology So often many argue over certain terms that can affect product acceptance, rejection or liability. Consider the word “failure.” I am certain we all have an idea of what constitutes a failure, but in what context? Try imposing limits or simply communicate the thought to another and the meanings will vary. This is one reason why the F16.01 committee was charged with drafting a definition for the committee on Terminology: to have a standard meaning. Because a failure does not necessarily mean a fracture, break or total separation, it also can also include failure from exceeding the material’s yield point, where it doesn’t exhibit any of the above characteristics. It can also fail a test procedure, such as not meeting it’s hardness requirements. A definition is supposed to be succinct. Yet, there may be several conditions to which the term may also apply. In that regard, I came up with four separate conditions for failure: Test Specimen, Test Procedure, Field Service and Application. We agreed upon the following. ASTM Update on Fastener Test Methods The F16 Committee on Fasteners has recently approved an update to the new test methods for Determining Carburization and Decarburization in Threaded Steel Fasteners, F2328 and F2328M (metric). After several years of draft revisions, in the attempt to produce a consensus document that was current with today’s laboratory practices and industry’s requirements, the F2328 and its metric counterpart, the F2328 have superseded references to the SAE standard. The significant change over the SAE standard requires the referee method to be an average of readings on four adjacent threads. Most test results are the average of at least three readings, this method provides for three additional microindentations adjacent to the first reading. This technique significantly reduces random variables. Failure: Test Specimen (product)—When a full sized fastener or fastener test specimen does not meet any of the product’s specified characteristics when tested to a specified test method. Test Procedure—When a test procedure produces inaccurate data as a result of an error in calibration, test equipment or operational procedure. The test data should therefore be discarded. Field Service—When a fastener does not function as intended in a connection during installation or while experiencing service loading. Further analysis is required to determine if cause is from product or application failure. Application—When a fastener does not function as intended as a direct result of an inaccurate installation, nonmatching fastener components, incorrect grade or type for the joint application or any other mechanism not related to the physical properties of the fastener being substandard. Think this was fun? We haven’t quite settled upon the proper definition for “fracture” yet. Recent Changes New on a recent ballot; paragraph 8.2.4 was removed as it invoked a fourth measurement. From results of round-robin testing with other laboratories, this requirement was deemed unnecessary and costly. The Metric F2328M allowed for four classes of products: the first having a minimum tensile strength of 830 MPa and a hardness of 24 to 34 Rc; the second having an ultimate tensile of 1040 MPa and a hardness range of 33 to 39 Rc; the third having an ultimate tensile of 1200 MPa or with a minimum specified hardness of 37 Rc; and the fourth is for products with recessed socket drives. Class four separated the special requirements of the socket drive products from the hex head series. Therefore, referenced standards included F574M, F835M and F912M. In addition, it was also approved to use the thread height measurement values in ISO 898 as it represented more accurate results. Even though routine practice cites the optical method as adequate, it is the shared opinion of several colleagues that for recessed drive products, the micro-indentation method should be employed, as these products are very susceptible to decarburization. GT Technical Consultants specializes in stateof-the-art information and maintenance solutions related to the applications, specifications, failure prevention, quality and assembly procedures of fastener products with safety training programs that are unique to the industry and designed to save downtime and costs. Other services include ISO 9000 Quality Manual preparation. Test your fastener knowledge. Visit www.BoltDoc.com and take the ‘Fastener Quiz.’ 80 Fastener Focus December 2007 http://www.BoltDoc.com http://www.BoltDoc.com http://www.BoltDoc.com

Table of Contents Feed for the Digital Edition of Fastener Technology International - December 2007/January 2008

Fastener Technology International - December 2007/January 2008 Contents Editorial Calendar Industry News 5S – Turbocharged Lean House Cleaning: Principles and Practices for Creating an Efficient Workspace Corporate News Mechanical Properties – Part 7: Strength & Ductility in Bending FTI Technical Achievement Awards — Class of 2007 The Heat Treatment of Fasteners — Practice Melt Shop Provides More Efficient Titanium Wire & Rod Production Spotlight On Simulation Comparing Preparation and Calibration Techniques for Ultrasonic Bolt Tension Measurement – Part 2 Future-Oriented Testing Equipment Wire Handling Roundup What’s Happening at the IFI? Product Showcases Machinery Product Showcases Quality Education & Training in 2008 Fastener Focus Quality Checks on Retaining Rings: Your Recipe for Success Straight From The Show: NIFS/WEST Spotlight on Plastic Fasteners Competence in Stainless Steel Pick More Orders in Less Time With Slotting New Fastener, Drive Systems & Insert Join a Proven Product Line ASTM Update on Fastener Test Methods – The Bolt Doctor Column Advertisers’ Index Classified Advertisements Editorial Index

Fastener Technology International - December 2007/January 2008

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