Author Topic: 6061-T651  (Read 2782 times)

Offline George

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6061-T651
« on: August 06, 2014, 11:09:41 AM »
I ordered a piece of aluminum 6061-T6 for a new mid plate and it is 6061-T651. I have looked online and don't think there is a problem but it's something I haven't seen before. Any problems associated with this material?

Thank You. George

Offline dreracecar

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Re: 6061-T651
« Reply #1 on: August 06, 2014, 12:04:17 PM »
To get to the -T6 temper, the 6061 is heated to about 990F, then quenched in water, then aged at about 350F for around 8 hours. That changes the typical yield strength from 8 ksi to about 40 ksi- fairly substantial.

But that quenching in water puts residual stresses in the aluminum, since there is a surface-to-center cooling gradient. The -T651 designation means the mill took that extrusion and gave it a 1% to 3% stretching, or permanent set, to get rid of some of those residual stresses.

Offline George

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Re: 6061-T651
« Reply #2 on: August 06, 2014, 05:33:09 PM »
To get to the -T6 temper, the 6061 is heated to about 990F, then quenched in water, then aged at about 350F for around 8 hours. That changes the typical yield strength from 8 ksi to about 40 ksi- fairly substantial.

But that quenching in water puts residual stresses in the aluminum, since there is a surface-to-center cooling gradient. The -T651 designation means the mill took that extrusion and gave it a 1% to 3% stretching, or permanent set, to get rid of some of those residual stresses.

Thanks Bruce. It all sounds good to me.

Offline Nightmare AA/FA

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Re: 6061-T651
« Reply #3 on: August 06, 2014, 07:11:25 PM »
To get to the -T6 temper, the 6061 is heated to about 990F, then quenched in water, then aged at about 350F for around 8 hours. That changes the typical yield strength from 8 ksi to about 40 ksi- fairly substantial.

But that quenching in water puts residual stresses in the aluminum, since there is a surface-to-center cooling gradient. The -T651 designation means the mill took that extrusion and gave it a 1% to 3% stretching, or permanent set, to get rid of some of those residual stresses.

Now there's a guy who knows his metal.

Offline dreracecar

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Re: 6061-T651
« Reply #4 on: August 06, 2014, 09:24:06 PM »
Also how to copy and paste