2/20/2013
HEADLINES
ISO Updates Carbon & Alloy Steel Bolt Standards

The International Standards Organization has published a new version of ISO 898-1, the fundamental mechanical property standard for carbon and alloy steel bolts, ahead of the five-year review schedule.

Fastener consultant Dr. John Newnham told Fastener+Fixing Magazine that it is an early update to the 2009 standard, which was “was quite controversial, and several aspects drew comments from national standards bodies.

The fundamental mechanical property standard for carbon and alloy steel bolts, which identifies the strength grades, permissible material types, and required tests and methods, is ISO 898-1. The standard defines the properties of ISO standard bolts, screws and studs, plus is called up in numerous proprietary drawings for non-standard fasteners.

“The ISO Technical Committee 2 sub-committee 11 drafted two amendments to the document to take account of the technical and editorial problems,” Newnham told F+F. “However the changes were so extensive that rather than issue the amendments separately, ISO 898-1 was re-published with all of the amendments included.”

There are no changes to the material types or strength grades, but there are increases to the maximum and minimum Brinell hardness values for property classes 8.8 and above.

Since ISO’s philosophy is that the latest issue applies, these changes could result in parts in stocked parts not complying with new requirements.

Other technical changes relate to the definitions and assessment of carburization and decarburization. There is a newly defined surface condition, ferritic decarburization, and there is a clarification of non-carburization which applies to strength grades 8.8 and above. There is also some revision to the way that these conditions must be assessed by microhardness tests and metallography so these need to be reviewed by test laboratories.

Newnham told Fastener+Fixing that ISO classifies this edition as a minor revision, but the technical changes are significant, and both manufacturers and distributors need to be aware of them. The new issue of EN ISO 898-1 is available from national standards organizations. ©2013 GlobalFastenerNews.com & Fastener + Fixing Magazine