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Grade 8 vs Grade BD vs Class 8.8 …..and let’s not forget B7


Grade 8 vs Grade BD vs Class 8.8...and let’s not forget B7.  

 

I recently had a customer ask me about the different High Tensile materials we can manufacture Threaded Rods and Studs from, in particular they were a little confused by the references to Class 8.8 and Grade 8 and was there a difference at all? 


Well, first and foremost all of these materials are High Strength, (High Tensile) steels and in the world of Threaded Rods and Studs,  if you are going to talk High Strength steels you should also include B7, so we have added that into this paper.

 

Comparing high strength material standards. ASTM ISO SAE standards

 

JS 429 GRADE 8


Let’s start with Grade 8 as it is one of the most commonly referenced high tensile materials in our industry, so much so that it has almost become a generic term, much like using a “Kleenex” [not tissue] to blow your nose or in the UK, doing the “Hoovering”, [not vacuuming] to clean the carpet. And yet as a raw material Grade 8 is not as readily available as say ASTM A354 Grade BD.

Grade 8 falls under the SAE J429 Standard which covers parts with thread diameters from 1/4” through to 1 1/2”.

 

ASTM A354 GRADE BD


Grade BD is a viable High Tensile alternative material to Grade 8, but much more easily available and offers a near identical strength to Grade 8.

Here at AATP we recently launched a range of High Tensile Threaded Rods and Studs under the GR8HT™ ROD, ( great-rod ) brand, these products are made exclusively by AATP here in Lancaster, PA and now available from stock. They are are fully certified to ASTM A354 Grade BD which covers parts with thread diameters from 1/4” through to 4”.  

 

ISO 898 CLASS 8.8


Not to be confused with Grade 8, Class 8.8 is a classification generally associated with Metric Fasteners. It falls under the ISO 898-1 standard which covers thread sizes M5 through to M39. Class 8.8 is defined as a High Tensile material and although not as strong as Grade BD or Grade 8 offers similar strength properties as A193 Grade B7 

 

ASTM A193 B7


Grade B7 is a High Tensile material that falls under the ASTM standard. Although not as strong as say Grade BD or Grade 8 it offers similar strength performance to Class 8.8 and is readily available as Threaded Rods or Studs.

 

For further details about AATP and our products, please visit us at www.aatprod.com