Originally Posted by fbagatelleblack

Prestige is heat-treated 4130. 4130 will always lose its temper in the heat-effected zone. The only way to re-establish the temper is by post-process heat treating.

It is entirely possible that Tange does not suggest/encourage/require heat treatment of Prestige tubing after welding, but if that is the case then they are simply accepting the fact that the tubing will be weaker in these areas. Since the welds are not generally in the most highly stressed parts of the frame, weaker tubing could be acceptable in these spots.

Yours,

FBB