Help -- Welder in Poland

By karpiel07 Date 05-27-2008 15:09

Hi All,

We're welding mtb bike frames in Europe and we've had the hardest time finding heat treaters for ALU 6061. We have a good vendor in the UK, but shipping back and forth is a costly nightmare. We're trying to work with Heatmasters locally, but we sent a test batch through them and the material came back too soft. They showed us a graph that indicated the test material had been solution annealed at 986 F for 30 minutes then quenched in water then aged at 350 F for 8 hours. This material seemed like it was T4 at best though. We're having it tested, but has anyone encountered something like this? We're desperate for answers here. Also, how long after aging does 6061 set at T6 (10-12 hours? is it hard right out of the oven?) Sorry for being such a newbie here, but i'm kind of between a rock and a hard place...

By thomasyyz (**)

Date 05-27-2008 21:11

maybe some one can bump this thread to the "Metallurgy" section, cheers!

By jrw159

Date 05-28-2008 02:33

I agree :-)

By jrw159

Date 05-28-2008 02:33

:-)

By gwg

Date 05-29-2008 04:21

Using my handy ASM Handbook on-line subscription

for 6061 extruded bar, shapes and tube

Solution treatment temperature 985 deg F , precipitation treatment for T6 350 deg F for 8 hours

By gwg

Date 05-29-2008 04:24

Keep in mind that the product form and how it was worked prior to heat treatment result in different properties. For example, drawn tube is subjected to a slightly different precipitation heat treatment 320 deg F for 18 hours to achieve a T6 temper.

By karpiel07 Date 05-29-2008 15:07

Thanks for your help! We think they might not have allowed the material to cool properly (i believe you have to wait 72 hours between the solution treatment and the precipitation processes). We believe they quenched the material and waited just an hour to start precipitation. In such a case, we're wondering if the material is permanently damaged, or if it can undergo another precipitation. Another consideration is their oven, which does not circulate air. Their oven is very precise and maintains a completely even temp throughout with the use of sensors inside the oven and on the material itself. So we have a bit of a puzzle. Any advice is greatly appreciated...

By gwg

Date 05-29-2008 23:16

karpiel07;
Where did you determine the source of the delay between solution treatment and precipitation heat treatment? It is not in any of the reference material I have (ASM Volume 4 Handbook on heat treating). Also, it makes no sense to me - the purpose of the solution treatment is to dissolve all elements into solid solution and precipitate them out at the required temeprature to form the correct size and distribution density of precipitates. I believe, if anything, the quench rate may be the problem. You need to cool as quickly as possible in a water quench tank that does not exceed 100 deg F during quenching. Look there.

By js55

Date 05-30-2008 13:34

I also have not seen anything about control over the time it took to remove the assembly from the furnace get it quenched. I don't remember the recommendation off hand but it ain't much for obvious reasons.

By karpiel07 Date 06-09-2008 13:32

Hello,

Thanks for all the help. The quench must be the problem then. We got the 72 hour wait suggeston from a publication put out by Easton several years ago. It seems to have less relevance.