4130 welding

["BillDube@killacycle.com" <BillDube@killacycle.com>]

Paul C wrote:

 > There are applications where 3140 is appropriate,
 > mostly where a
 > significant degree of flexure is expected, i.e. aircraft and
 > bicycle frames.

It's worth noting here that most of the frame gurus insist on TIG welding
4130, even though it was *designed* for gas welding.  TIG gives you pretty
welds.  It also causes drastic thermal transients in the metal, which is why
you have to treat it after a TIG weld.  The PROPER way to do it is to use a
big, soft gas flame and take our time.  That ensures heat spreads gradually
throughout the area.  Yeah, the welds look cobby.  They're also probably
stronger.


 >>>>>>>>>>>>>>>>>

	The American Welding Society specifies TIG as the best method for welding 
4130 tubing. If you wish to get technical it is not "TIG" but, according to 
the AWS, it is "GTAW." This stands of Gas Tungsten Arc Welding. They call 
it this because the shield gas is often not truly "inert." GTAW results in 
the best weld strength for 4130 tubing.

	If you are going for the absolute top strength, you must heat treat the 
entire completed structure in a tempering oven. This relieves all the 
thermally-induced stress in the heat-effected zones, but also converts all 
the martensite back to austenite to restore the full toughness of 4130.


    _ /|        Bill "Wisenheimer" Dube'
   \'o.O'     <billdube@KillaCycle.com>
=(___)=
        U
Check out the bike -> http://www.KillaCycle.com
    _ /|        Bill "Wisenheimer" Dube'
   \'o.O'     <billdube@KillaCycle.com>
=(___)=
        U
Check out the bike -> http://www.KillaCycle.com