Heat treat of 2014/2219/355 welded assy
Heat treat of 2014/2219/355 welded assy
(OP)
I have a 355 cast aluminum housing that has been previously welded and heat treated. I am looking for a postweld heat treatment after welding a new piece of 2219-t3 plate and 2014-t6 bar stock to the housing(2219 plate directly to the housing, then the 2014 piece to the 2219 plate). I plan on using 2319 filler rod. I understand that I will be overaging material that has previously been aged, that is the casting and other wrought sections already welded to it. What would be a good compromise for postweld heat treat time and temperature? My goal is to maximize strength in the HAZ, and I was going to start with 4-6 hours at 325F. Obviously this will not produce a T8 hardness in all the components but I have to compromise in some way here, so I think this should give me something acceptable. Any input would be appreciated.





RE: Heat treat of 2014/2219/355 welded assy
How about fully solutioning the assembly after you weld the new parts into it? Then age it as an assembly.
Regards,
matlsguy
RE: Heat treat of 2014/2219/355 welded assy
RE: Heat treat of 2014/2219/355 welded assy
I just checked my ASM Heat Treating Handbook. I need to make a few points. 325F (162C) is too low a temperature to stress relieve the fixture after welding. That temperature is the optimal aging temperature for these alloys. To stress relieve, you need a greater amount of diffusion; thus the temperature needs to be higher. ASM reccomends 500F-800F.
Next point, since you are heat treating A355 (high thermal conductivity and thus low thermal stresses) warpage shouldn't be a problem if a reasonably low temperature ramp up and ramp down rate is used.
Last point, is you heat treat in a argon atmosphere the machined surfaces should't be ruined. Surface finish shouldn't be an issue since you are going to have to heat treat above 500F anyways for stress relieve
I think you can still get a T8 hardness. Good Luck!
Matlsguy
RE: Heat treat of 2014/2219/355 welded assy
RE: Heat treat of 2014/2219/355 welded assy
I would think you need to stress relieve after welding the assembly prior to aging. For the solutionizing process, you might need a fixture to prevent any distortion if you plan on oil quenching. To quench this material you don't need the high quench rates such as that to form martensite as with steels. You might be able to get away with backfilling the furnace with argon at a high turnover rate. Distortion will be minimal using this quenching method. I would recommend stress relieving, then solutioning, then aging.
Matlsguy
RE: Heat treat of 2014/2219/355 welded assy
RE: Heat treat of 2014/2219/355 welded assy
RE: Heat treat of 2014/2219/355 welded assy
RE: Heat treat of 2014/2219/355 welded assy
RE: Heat treat of 2014/2219/355 welded assy
matlsguy