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From: ------
Welded 6061-T6 is not T6 anymore. Depending on design intent you may or maynot need to reheat-treat the tool. When you weld 6061-T6 it will consist of portions of unaffected metal and inhomogeneous welded areas (heat-affected zones). I don't know what the specification is to heat treat 6061 but, to heat treat a 6061 weldment, one needs only to find a furnace large enough to fit your welded components inside. Heat-Treatment varies with the size of part and its alloyed composition. The T6 temper designation means that the aluminum alloy is "Solution Heat Treated and Artificially Aged", and consequently NOT cold-worked. Since 6061 has a great combination of strength and toughness/ductility, it is popular material of choice. Post-welded heat-treatment is necessary to achieve maximum materials properties.
To Re-Heat-Treat 6061-T6,
STEP 1) Solution Heat Treat for about 2 hours at 530 deg C. This will cause the solute alloying atoms to become evenly distributed within the part. This changes the temper to T4.
STEP 2) IMMEDIATELY quench the part after removal from the furnace in room temperature water. This will effectively freeze the solute atoms in place. Remove it when it's comfortable to touch.
STEP 3) Artificially Age-Harden the part for 18 hours at 160 deg C. This will cause the solute atoms to chemically react and precipitate into micron-sized particles and thus significantly strengthen the alloy into its wonderfully useful form.
It is important not to let the furnace deviate more than 5 deg C from the heat treatment temperature you need. Furnace temperature settings are notorious for being wrong, so double check with a type K thermcouple. If you are using other alloys, heat treatment schedules can be found in the ASM Handbook, Vol. 4. This text includes iron, aluminum, magnesium, and titanium alloys plus others.
Good luck,
From: ------
Hi, I have an older, Late "40's"- early "50's" Norton Universal Grinder with angle heads and would like your opinion of the Live Center type which should be used , I am grinding a 1.0 inch area of a 5.0 inch titanium tube which is thermal sprayed , I am currently using a boss that is taper fitted to a modified 60 degree floating center and I believe the center is the wrong type for this type of use. Any suggestions would be appreciated greatly. Thank You
Robert J. Knapke