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More Changes to ISO 898-1 on the Way
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2012-03-14
Dr John Newnham, Fastener Specialist for the Confederation of British Metalforming, foresees significant effects for fastener manufacturers and distributors. Here he explains why he believes fastener companies need to be alert to the implications of the forthcoming revision of ISO 898-1.
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. This standard is not just used to define the properties of ISO standard bolts, screws and studs, but is called up in numerous proprietary drawings. The latest version of this standard was issued in 2009, but unfortunately, a substantial number of changes have already been agreed, and it is likely that a complete new standard may be issued shortly.
The 2009 issue was quite controversial, and several aspects drew negative comments. As a result, ISO Technical Committee 2 sub-committee 11 has drafted amendments to the document to take account of perceived problems, and the changes are so extensive that they have recommended re-publication of ISO 898-1.
The draft changes include some technical revisions, as well as numerous editorial revisions for clarification, and the usual updates where necessary, relating to reference standards. The newly agreed ISO practice of not dating the reference standards is followed, so the latest issue of any quoted standard now applies.
One series of technical changes is concerned with the definitions and assessment of carburization and decarburization. There is a newly defined surface condition, ferritic decarburization, and there is also a clarification of non-carburization which applies to strength grades 8.8 and above, previously defined tests not being feasible for lower strength grades. There is also some revision to the way that these conditions are assessed by microhardness tests and metallography.
Of significant concern also are increases to the maximum and minimum Brinell hardness values for property classes 8.8 and above. Given that the new ISO philosophy relating to updated standards is that the latest issue applies, these changes could result in parts being in stock that do not comply with the new requirements, and in one country at least, these would no longer be acceptable. For more information about the CBM and to contact the confederation visit www.britishmetalforming.com
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. This standard is not just used to define the properties of ISO standard bolts, screws and studs, but is called up in numerous proprietary drawings. The latest version of this standard was issued in 2009, but unfortunately, a substantial number of changes have already been agreed, and it is likely that a complete new standard may be issued shortly.
The 2009 issue was quite controversial, and several aspects drew negative comments. As a result, ISO Technical Committee 2 sub-committee 11 has drafted amendments to the document to take account of perceived problems, and the changes are so extensive that they have recommended re-publication of ISO 898-1.
The draft changes include some technical revisions, as well as numerous editorial revisions for clarification, and the usual updates where necessary, relating to reference standards. The newly agreed ISO practice of not dating the reference standards is followed, so the latest issue of any quoted standard now applies.
One series of technical changes is concerned with the definitions and assessment of carburization and decarburization. There is a newly defined surface condition, ferritic decarburization, and there is also a clarification of non-carburization which applies to strength grades 8.8 and above, previously defined tests not being feasible for lower strength grades. There is also some revision to the way that these conditions are assessed by microhardness tests and metallography.
Of significant concern also are increases to the maximum and minimum Brinell hardness values for property classes 8.8 and above. Given that the new ISO philosophy relating to updated standards is that the latest issue applies, these changes could result in parts being in stock that do not comply with the new requirements, and in one country at least, these would no longer be acceptable. For more information about the CBM and to contact the confederation visit www.britishmetalforming.com
