Specs for ASTM A153 AND ASTM A194-2005a

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Sir,
What is the difference between ASTM A153 AND ASTM A194-2005a

Thomas Mathew
Senior Structural Engineer - Kuwait

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The 'Scope' of each ASTM specification is available at http://www.techstreet.com & http://www.astm.org
See ASTM A153 [link is to spec at TechStreet], 'Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware' and A194, 'Standard Specification for Carbon and Alloy Steel Nuts for Bolts for High Pressure or High Temperature Service, or Both.'

Any coating of fasteners, and whether nut threads are cut before or after coating, must be specified in the ASTM A194 manufacturing process. An * suffix added to the nut grade indicates zinc coating. ASTM A153 provides a nominal zinc thickness of 43 microns on small (3/8" or 9.52 mm diameter) fasteners, 53 microns on larger.

Also, zinc coated fasteners should only be used at temperatures below 390 °F [210 °C] to avoid possible embrittlement (per Appendix X2 of A194).

Ken Vlach
- Goleta, California