6061 T6 vs 5052 for an automotive stiffening panel?

M

moespeeds

Plastic

Joined

Mar 3, 2011

Location

Cherry Hill, NJ

• Mar 22, 2012

• #1

Hey guys I want to replace a tunnel stiffening panel in my Corvette track car with something stiffer. Right now it's 3/32" Aluminum, grade unknown. I see panels sold online in 1/4" and 3/8", 6061 T6 for around $400. The panel is flat and fairly easy to duplicate, but locally I can only get 5052 in 3/8" plate in the size I need. I'm completely ignorant to the properties of either grade, but I do know 6061 T6 is the stronger of the two. No welding or anything like that will be required, just cutting to size and drilling some holes. 3/8: is as thick as I can go because of clearance issues, so making it thicker won't work. Think I'm ok with 5052? Any advice is appreciated...

 

Finegrain

Diamond

Joined

Sep 6, 2007

Location

Seattle, Washington

• Mar 22, 2012

• #2

The strength is irrelevant if what you care about is stiffness. If it really is just about stiffness get whichever Al is cheapest and available.

Regards.

Mike

 

S

SND

Diamond

Joined

Jan 12, 2003

Location

Canada

• Mar 22, 2012

• #3

5052 is definitely gummier. I'm no expert at all with metallurgy but from what I've played with, I think with aluminum the grade and temper and how its rolled not only affects strength but stiffness as well. It's possible that either one will work just fine for what you are doing depending on how much stress it actually sees, but I tend to have a little more faith in 6061.
I'm surprised they don't have it in sheet/plate in your area, 6061 is as common as it gets.

 

annoying

Hot Rolled

Joined

Apr 22, 2010

Location

IN, USA

• Mar 22, 2012

• #4

moespeeds said:

Hey guys I want to replace a tunnel stiffening panel in my Corvette track car with something stiffer. Right now it's 3/32" Aluminum, grade unknown. I see panels sold online in 1/4" and 3/8", 6061 T6 for around $400. The panel is flat and fairly easy to duplicate, but locally I can only get 5052 in 3/8" plate in the size I need. I'm completely ignorant to the properties of either grade, but I do know 6061 T6 is the stronger of the two. No welding or anything like that will be required, just cutting to size and drilling some holes. 3/8: is as thick as I can go because of clearance issues, so making it thicker won't work. Think I'm ok with 5052? Any advice is appreciated...

Click to expand...

How big do you need?? you should look around a bit more or look at onlinemetals.com or something. Gotta be something closer to you though... I'd think

 

C

CougarMountain

Hot Rolled

Joined

Jan 28, 2010

Location

Oregon

• Mar 22, 2012

• #5

6061 would be a better choice if you want a material that's better at holding it's shape. 5052 is more for applications that need to be formed. A common alloy in used in boats for example. Also, 5052 doesn't lose it's strength in heat affected zones, such as when welded, like 6061 will. 7075 is even stiffer, like a spring. Used alot in aircraft applications. What ever material you use, make sure it's extruded, or rolled, and not cast, as in tooling plate.

 

Spencer in NH

Stainless

Joined

Jan 22, 2007

Location

Southern New Hampshire

• Mar 22, 2012

• #6

Stiffness is a linear property. What that means is if you have a beam (sheet, rod, whatever) and you push on it a little, it will bend a little and come back to exactly where it was before you pushed on it. How much pressure you used to make it move a certain amount is stiffness.

Stiffness is NOT A FUNCTION OF ALLOY within a basic metal species. So, 6061, 5052, 7075 aluminums are all going to have the same stiffness. So, base your choice on the next thing on the list. Welding it? 6061. Bending it? 5052. Maximum yield strength? 7075 (and bring yer checkbook).

Stiffness is NOT A FUNCTION OF ALLOY within a basic metal species.

 

C

CougarMountain

Hot Rolled

Joined

Jan 28, 2010

Location

Oregon

• Mar 22, 2012

• #7

Doesn't stiffness have a relation to yield strength?, as in deflection?
5052-H32 yield= 28000psi
6061-T6 yield=35000psi
7075-T6 yield=65000psi

 

Spencer in NH

Stainless

Joined

Jan 22, 2007

Location

Southern New Hampshire

• Mar 22, 2012

• #8

Look at Young's Modulus... That is stiffness.

Young's modulus - Wikipedia, the free encyclopedia

"Young's modulus, also known as the tensile modulus, is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds."

Yield is a non-linear property. Once yielded, the metal is forever changed... i.e. bent, deformed.

It takes more force to bend a beam of 7075 to the yield point than it does 6061, or 5052, in turn. So, a force that is a temporary "deflection" for 7075 may be a permanent bend in 6061.

The short answer, CougarMountain, is: no.

5052-H32 yield= 28000psi modulus=10.2 ksi
6061-T6 yield=35000psi modulus=10.0 ksi
7075-T6 yield=65000psi modulus=10.4 ksi

 

dfw5914

Stainless

Joined

Apr 1, 2006

Location

Sanctuary, TX

• Mar 22, 2012

• #9

The higher yield strength materials are springier not stiffer.
Steel would be around three times as stiff as aluminum and is around three times as heavy.
So if stiff is the goal with limited space, you can reach maximum stiffness with steel and the weight will be a wash.
In other words, a 1/8" thick steel panel would be comparable to a 3/8" thick aluminum panel in both weight and stiffness.
Plus steel wont transmit so much heat.

 

K

kustomizingkid

Titanium

Joined

Aug 2, 2010

Location

Minnesota

• Mar 22, 2012

• #10

If you want to gain stiffness of the panel change the shape, Add thickness, or some other type of 3D feature. IF you really wanted to get exotic get some CF and Nomex core and bond it in

 

W

wesg

Titanium

Joined

Nov 4, 2004

Location

Cedar Park, TX - Boulder Creek/Redwood City, CA

• Mar 22, 2012

• #11

Stiffness goes up by the cube of the thickness, so the 3/8" aluminum panel would be the same weight as 1/8" steel, but 9x stiffer.

 

dfw5914

Stainless

Joined

Apr 1, 2006

Location

Sanctuary, TX

• Mar 22, 2012

• #12

The exhaust runs directly below this panel, I don't think any bonded structures would last.

 

K

kustomizingkid

Titanium

Joined

Aug 2, 2010

Location

Minnesota

• Mar 22, 2012

• #13

dfw5914 said:

The exhaust runs directly below this panel, I don't think any bonded structures would last.

Click to expand...

Carbon Fiber and adhesives are much more heat resistant than you would think... and there are high heat resins and adhesive, but it doesn't really matter as I highly doubt the OP would go for something that exotic.

 

S

ss_again

Aluminum

Joined

Jun 22, 2010

Location

TX, USA

• Mar 22, 2012

• #14

dfw5914 is correct but let me add to it a little. Maybe this can help clear it up a little.

Young's modulus is the typically called "elasticity" of the material not the stiffness of a structure but does play a big part in the total stiffness. The other factor that has to be considered is the cross-sectional area (A) for axial stiffness and the moment of inertial area (I) for bending stiffness.
Take for example a rectangular bar of length (L), rigidly held on one end with a force is applied at the other.

Let K = stiffness in units of lb/in

K_axial = A*E/L

K_bending = 3*E*I / L^3
(Note that "I" varies with cross-sectional shape of part and for a rectangular bar it is b*t^3/12 where "b" is the width and "t" is the thickness)

Hope that helps some.

 

Last edited: Mar 22, 2012

dfw5914

Stainless

Joined

Apr 1, 2006

Location

Sanctuary, TX

• Mar 22, 2012

• #15

wesg said:

Stiffness goes up by the cube of the thickness, so the 3/8" aluminum panel would be the same weight as 1/8" steel, but 9x stiffer.

Click to expand...

Forgot about that.