6082-T6 equivalent in MMPDS-06? 1

[JBlack68]

To all,

I am bit stuck. I am using 6082-T6 stress allowable but was adviced/told (by the customer) that;
1. (strength) data must be taken from MMPDS-06
2. knock-down factor (strength reduction) must be taken at 200degF

Question is: Does anyone know what would be the equivalent to 6082-T6 in MMPDS? I cannot think anything

any help or pointer would be greatly appreciated

Thanks
Regards

JXB0809

 

[TVP]

6061-T6 is the closest grade in MMPDS-06.

 

[JBlack68]

Thanks. Much appreciated

 

[RPstress]

Caution: 6082 is commonly used for salt water marine service. 6061 should not be used in seawater; its copper content renders it vulnerable to corrosion.

 

[JBlack68]

Looking at MMPDS-05 for 6061 as pointed toward by fellow forum members. I have a (really) stupid question but if one does not ask...

Figure 3.6.2.2.1(a). Effect of temperature on the tensile ultimate strength (Ftu) of 6061-T6 aluminum alloy (all products).
and
Figure 3.6.2.2.1(c). Effect of exposure at elevated temperatures on the room temperature tensile ultimate strength (Ftu) of 6061-T6 aluminum alloy (all products).

What is the difference between the 2 curves? Is the 2nd curve more a creep related data?

Thanks
Regards
JXB

 

[mp87]

Hi,

[ul]
[li]Figure 3.6.2.2.1(a) refers to Ftu measured at high temperature after a certain dwell time at that temperature.[/li]
[li]Figure 3.6.2.2.1(c) is instead related to Ftu measured at room temperature after a certain dwell time at high temperature.[/li]
[/ul]

 

[RPstress]

The (a) and (b) curves are the instantaneous heat factor, the property at the specified temperature after letting it soak for the specified time.
The (c) and (d) curves are the effect of toasting the alloy at the specified temperature for the specified time then letting it cool down; has the toasting permanently damaged the alloy and if so how much will it recover its pre-toasting strengths?

If you're going to hold it at temperature for a year or so (10,000 hours) then (d) says its yield is permanently reduced at any temperature above about 250°F. (b) says the actual yield at 250°F is 88% of the RT value (and also that it doesn't matter how long it's held at 250°F; even after a half hour it has dropped to 88%).

PS: in my previous post I should have cited a reference: it was in Professional Boat Builder February/March 2014
"Altered Properties
Understanding how the structural characteristics of aluminum alloys change during construction is essential for boat designers and builders", by John Kecsmar.
That's available on the web if you have been given access (they seem happy to give access to people who are at least somewhat involved professionally). PBB has a lot of good information about aluminum, steel and composite in the industry.

 

[RPstress]

PS: Sorry mp87. I wasn't criticizing your post; you just beat me to it (I delayed posting for bit after starting to answer).

 

[JBlack68]

Thanks for the clarification. I guess I need to use curve (a). At this moment in time the only info I have is
"Material allowable shall be taken at 200deg F from MMPDS-06"

 

[mp87]

@RPstress

No need to apologise at all, two answers are better than one and yours was indeed more detailed than mine.