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  for Metal Finishing since 1989
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STEEL PROPERTIES

2004

Hi,

I would like to know the difference between a class of steel and a grade of steel. I translate documents for the shipbuilding industry and bolts and rods often have reference numbers and letter after them. If I get the translation wrong this could cause big problems for the shipyard staff.

Thanks,

Kevin Furber
Technical translator - Guidel, Morbihan, France

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Kevin,

As you already know, one definitely needs to use as much precision as possible when 1) translating documents from one language to another and 2) using reference terms that may vary from country to country or from industry to industry. A "grade" of steel usually refers to a specific chemical composition. The term "class" or "property class" is used in the fastener industry to describe the mechanical property requirements for nuts, bolts, screws, etc. For a given property class, such as Property Class 10.9 from ISO 898-1, many different grades of steel (with differing chemical compositions) can be used as long as they meet the strength, hardness, and other requirements. I hope this was helpful. Feel free to post again if you need additional clarification.

Toby Padfield
Automotive supplier - Michigan
2004