different opinions regarding 2014 aluminum alloy 1

[MetalEng]

According to fig.11.25 of Metals Handbook,vol2 9th ed., 18 minutes in 204 C can lead to Min. Y.P. and Min. Ductility equal to 345 MPa and 13%,respectively. I don't believe that and I think this results may be affected by many other parameters. What's your opinions?

 

[Metalguy]

Do you think the values are too low or too high?

 

[MetalEng]

I think this holding time would be too short and it will not practically lead to enough hardening!

 

[MetalEng]

dear unclesyd, thank you for reply.
these conditions, will be led to those mechanical prperties?

 

[unclesyd]

2014: ultimate; yield; Elong(%) ; shear; endurance; hardness(500kg/10mm)

All values in kg/mm[sup]2[/sup]

O – 19.0; 9.8; 18; 12.7; 9.1; 45

T3– 45.0; 28.8; 20%

T4,T451–43.6; 29.5; 20%; 26.7; 14.1; 105

T6,T651–42.9; 42.2; 13%; 29.5; 12.7; 135

2014 T-4,T451: die forgings will have yields approximately 20% lower.

2014 T-6,T651: extruded shapes greater than 3/4" thick will have strengths (TS,YS) 15%-20% higher than the listed values

 

[swall]

Time should be 18 HOURS not 18 minutes!

 

[MetalEng]

Hi SWALL,
Could you tell me more about your opinion?

 

[swall]

As luck would have it , I have the 8th edition and 10th editions at work, but 9th edition is at home.I will take a look at that figure this evening.My assumption at this point is that we are talking about a 204C temperature excursion on top of a standard T6 treatment for 2014.

 

[MetalEng]

dear swall,
i think 18 min. is not industrially practical and 149 C/10 HR IS BETTER.

 

[unclesyd]

MetalEng & swall
Sorry about my erroneous posting about the time @ Temp as minutes instead of the correct hours. I can't blame that one on nobody but myself.

One more correction needs to be made and that is the 2014 T6 Ultimate tensile needs to be 49.2 instead of 42.9

The times I have fron ALCOA Handbooks for 2014 T6 precipitation heat treating are all 18 Hours @ 160°C for every form except the forgings. 2014 T6 Forgings are 10 Hrs @ 172°C.

 

[MetalEng]

dear unclesyd,
thank you again.
Finally, what's your opinion about 204 C/18 minutes?

 

[unclesyd]

At the present I concur that this is a error. In the three books (all prior to 1990) that I have list the time at temperature for the T6 condition as 18Hrs, again with the exception of forgings, which is 10 hours. This included reading all of ALCOA's ubiquitous footnotes. The shortest mentioned time at temperature for any alloy is 1 hour. The shortest time for any 2000 series alloy is 6 hours.

I lost my ultimate reference just prior to retiring, but I know who has one I’ll try to get up with him as see what other information is available.

I would also query ASM by e-mail and ask them to verify the numbers or if in error what are the correct numbers. I know they have done this on several occasions.

It might not hurt to query the producer of the material for a product data or technical sheet for this material.

 

[metengr]

MetalEng;
The 2014 aluminum alloy has a T6510 temper. The alloy is subjected to a solution treatment, stress relieved by stretching to produce a 1-3% permanent strain followed by an artifical aging at 320 deg F.

 

[MetalEng]

dear metengr,
thanks a lot. Could you gove me a reference about your opinion as well as some data about the resulted mechanical properties?

 

[MetalEng]

dear unclesyd,
thank you.
please let me know detailed result of your survey.
Bon Courage.

 

[unclesyd]

Looks like I’ll have to eat crow again. Look at the conclusions drawn on the last 2 references.

Look at the following website at Ohio State at the curves on 2014. The reference is to William D. Callister and there are 6 books on Amazon by him about material science.
Some recent graduate might know which book is being referenced.

http://er6s1.eng.ohio-state.edu/mse/mse205/lectures/chapter11/chap11.pdf

Here is another reference to chapter 11 of ??? and I’ll bet all are books by Callister as one of his books chapter 11 is heat treatment of metals..

http://www.clarkson.edu/class/es260/Chap11Solns.PDF

This another website with the same data from chapter 11 but different parameters

http://web.utk.edu/~prack/mse201/HW7.pdf

 

[MetalEng]

dear unclesyd,
I have already known about these references that you gave but I don't believe those. You mean that you got back on your prior opinion?

 

[unclesyd]

At the present I tend to go with ALCOA. With what little data I have I believe the values would fall in the subject ranges mention in the references. I would like to see data on other properties before stand on one set of values or the other. I try to see if I can access a copy of either of the newer books. Also so I would like to get an opinion from an AL producer. The values for time at temperature given in the problems have a very wide range, and I stated It seems any value would work.

This is almost as interesting as the time my boss turned a tempering oven with a 100 #s' of high dollar Al castings up to 1250°F without looking in the oven.

 

[swall]

MetalEng--This is what I think about the 18 minutes at 204C.I think the 345MPa and 13% figures are valid, at least to the point that one could pick them off the ageing curve.But, they may not represent actual data points obtained when the ageing curve was run (i.e. you get interpolated data when you pick a point on the curve).And no, I do not think this would be a practical heat treatment.It is a one time result that some researcher got when he ran an ageing experiment.The published heat treatments in the Aluminum Association and Alcoa handbooks have been well validated and tested. If you pick one wild heat treat off a graph, you have no way of knowing what the fatigue properties, SCC properties or residual stress level in the product might be.You only have that one bit of data, i.e. the YS and %E.