Bassmark
Mechanical
- Dec 2, 2022
- 2
Hey All,
I am looking to learn how the serration dimensions on a ASME B16.5 raised face (RF) are derived from ASME B16.5.
Currently, for say, an 8" class 300 RF flange with concentric serrations, ASME B16.5 section 6.5.4.3 states:
"Either a serrated concentric or serrated spiral finish having a resultant surface finish from 3.2 micro-m to 6.3 micro-m (125 micro-in. to 250 micro-in.) average roughness shall be furnished. The cutting tool employed should have an approximate 1.5 mm (0.06 in.) or larger radius, and there should be from 1.8 grooves/ mm through 2.2 grooves/mm (45 grooves/in. through 55 grooves/in.)"
The spec calls out surface roughness of 125-250Ra and 45-55 pitch (recommended value), machined with a 1/16" rounded tip cutting tool. However, when I perform a quick online search, I find information which state the ASME B16.5 requirements for a concentric lay serration are to machine grooves using a 90-degree included angle "V" tool with grooves 1/64" deep and 1/32" wide.
Would serrations machined to these parameters be in accordance with ASME B16.5?
The calculated the RA value of the for said serrations was found to be 3500 micro-in which is far above the stated limit of 250 micro-in.
Maybe this is just a massive brain-fart, but I fear that when I'm questioned on the origins of the serration callout on a drawing, I wouldn't be able to point to a place in the specification and provide an explanation.
If anyone can provide some clarification on this matter, it would be much appreciated.
Bassmark
I am looking to learn how the serration dimensions on a ASME B16.5 raised face (RF) are derived from ASME B16.5.
Currently, for say, an 8" class 300 RF flange with concentric serrations, ASME B16.5 section 6.5.4.3 states:
"Either a serrated concentric or serrated spiral finish having a resultant surface finish from 3.2 micro-m to 6.3 micro-m (125 micro-in. to 250 micro-in.) average roughness shall be furnished. The cutting tool employed should have an approximate 1.5 mm (0.06 in.) or larger radius, and there should be from 1.8 grooves/ mm through 2.2 grooves/mm (45 grooves/in. through 55 grooves/in.)"
The spec calls out surface roughness of 125-250Ra and 45-55 pitch (recommended value), machined with a 1/16" rounded tip cutting tool. However, when I perform a quick online search, I find information which state the ASME B16.5 requirements for a concentric lay serration are to machine grooves using a 90-degree included angle "V" tool with grooves 1/64" deep and 1/32" wide.
Would serrations machined to these parameters be in accordance with ASME B16.5?
The calculated the RA value of the for said serrations was found to be 3500 micro-in which is far above the stated limit of 250 micro-in.
Maybe this is just a massive brain-fart, but I fear that when I'm questioned on the origins of the serration callout on a drawing, I wouldn't be able to point to a place in the specification and provide an explanation.
If anyone can provide some clarification on this matter, it would be much appreciated.
Bassmark
