Reynolds 531 DB Tubing : Seamed : Impossible ??
I thought there was a REALLY GOOD reason why Reynolds NEVER made 531 seamed tubing. I thought that there were strength problems in welding generic manganese-moly tubing. I'm not certain about this because certainly there were aircraft frames made in WWII with Reynolds 531 tubing, but perhaps they had to be carefully brazed or the butts had to be overly large.
Anyway, because 531 is not good for welding that's why just about all the seamed tubing in the world is chromoly, which loses less strength after welding.
http://reynoldstechnology.biz/
And that's why Reynolds only offers special air-hardened steels for welding purposes. I think the dirty little secret here is that only 531 and 753 are manganese-moly frames without chromium, because britain had better access to manganese than chromium, and all other series of reynolds steels are flavors of chromoly (where chromium is dominant over manganese, if any), actually.
- Don Gillies
San Diego, CA, USA