# Tag Info

20

I believe it has less to do with strength and more to do with stiffness. A rod of aluminum of the same length and weight as a a steel rod will be just as strong (force required to break) but have three times the cross-sectional area which hugely increases the second moment of inertia by nine times (it scales to the fourth power of distance/length which is ...

15

If furnished in a thin, polished sheet, aluminum will reflect infrared radiation, as for instance in a so-called "space blanket" which consists of a thin sheet of plastic on which a thin and smooth layer of aluminum has been deposited. In this context, the aluminum can prevent heat losses by reflecting infrared radiation. But if that thin sheet of ...

13

Yes, steel (even some stainless) may be cheaper than aluminum, but the material cost of an item is seldom the majority of the total cost, especially a small item such as a potato peeler. Making aluminum parts with complex, curved shapes can be fairly easily done by casting. Aluminum pours at around 1500 °F, which can be achieved with low-cost furnaces and ...

10

The work history and temperature history of any metal can make a big difference in the final shape after machining. If the material was cold worked (e.g. rolled) there may be significant residual stresses within the material. When you start selectively removing material, those stresses may cause the part to warp into a new shape. Cast metals and ones that ...

10

A very important property of steel used in reinforced concrete is that it has similar coefficient of thermal expansion as concrete: Concrete: $14.5 \cdot 10^{-6} \frac{m}{m\,K}$ Steel: $12.0 \cdot 10^{-6} \frac{m}{m\,K}$ Compare this with: Aluminum: $22.2 \cdot 10^{-6} \frac{m}{m\,K}$ So a likely result of putting aluminum inside a concrete beam would ...

9

TL;DR: Materials perform differently under different loading conditions. Some applications are more suited for steel others for aluminium I will try to give another more general perspective/approach, using the concept of material indices (mainly other users gave perfectly adequate explanations of the differences between bending and tension and stiffness vs ...

9

It really depends on what you are trying to do with it. And thermal "conductors" and "insulators" are not a hard and fast distinction in properties like electric conductors or insulators. Every material just has a certain thermal conductivity, so compared to say diamond, aluminum has low conductivity. With foil, wrapping it with air ...

8

I'm going to run with this assuming the arm looks like the following diagram (I'm ignoring the 11.4 pounds of the bar for now to make the concepts easier to explain - that can be added later by assuming all 11.4 pounds run through the center of the bar.): This is a pretty simple setup. To figure out the loading on the shaft, we have to move the load from ...

7

Most soda cans in the US are on the order of 0.1 mm thick according to the sources I've seen. So 0.25 mm seems plausible to me, assuming that you made no errors in your calculations.

7

You can use a sort of "double diameter washer". I've made that name up, but I am pretty sure such a device exists: That's a cross section of one of your linkages. The white things are the aluminum pieces, the grey one is the screw, the yellow is the nut while the red is the "double diameter washer". If you can found some washer that is ...

7

In short: you can't use aluminium to reinforce concrete. You shouldn't even embed uncoated aluminium in concrete. Quoting Corrosion of Non Ferrous Metals in Contact with Concrete, "Aluminium suffers attack when embedded in concrete". Corrosion of aluminium embedded in concrete causes total destruction of aluminium bars, therefore it's dangerous and ...

6

I looked up 6000 grade aluminum to be about \$2/kg, while 304 stainless steel is about \$3.40/kg. This means stainless steel is about 70% more expensive than aluminum, which is consistent with my experience in doing mechanical design. I'm not sure where your numbers came from that aluminum is 4x more expensive than stainless steel. I also have a ...

6

Summary The general term for changing tube and pipe diameter is swaging. The tools you are looking for exist but vary widely in price and complexity. It may be more straightforward to find a local metal supplier who can do the swaging for you based on your specifications. Flaring vs. Swaging I am unsure if there is a specific name for the process which is ...

6

Using your plate as boat hull implies a complex load profile probably involving compression, shear and bending, possibly even torsion. In such cases, it is effectively impossible to give a simple answer to your question. @RainerJ's answer is perfectly acceptable for tensile and shear loads: if you're replacing material X with material Y and Y's yield ...

6

Sometimes the strength isn't required, so size for size, aluminium is lighter. e.g. bicycles often use aluminium screws to hold the bottle cage to the frame. The size of the screw is set to be comfortable to handle, and to accept the same size Allen key as other screws on the bike. But, it doesn't need to be super strong as it's not taking a critical or high ...

6

An option available to you along with welding is a product known as aluminum brazing rod. When aluminum is heated to melting point, an oxide forms which prevents bonding. In a welding environment, a flux or enclosing gas is used to prevent the oxide. The aluminum brazing rod works in a different manner, by reacting with the aluminum and forming a different ...

5

The dross is mostly composed of aluminium oxide which is already present on the surface of the metal before it even goes into the furnace, as the aluminium melts the oxides separate and float to the top. Recycled aluminium will tend to be made up of relatively thin material with a high surface area to volume ratio and so a relatively high proportion of ...

5

A shoulder bolt is a good approach in applications with light loading, but it needs to be specified such that it can be fully tightened while still allowing the necessary clearance for movement without binding. Use shims where needed. You can reduce some of the play in the joint by having the bolt threaded into one of the aluminum pieces (but still backed ...

5

The Wikipedia page puts tin foil thickness at between 0.2 mm and 0.006 mm. That means that the upper end of the tin foil is easily comparable with the thickness of my box. Ooook. Let's look at this, from an engineering perspective. First, scales. The smallest measurement from Wikipedia vs the largest is a 33x factor difference. This is perhaps hard to ...

5

We use this equation for a simply supported beam loaded at its center with 200lbs. M= P x L/4 =200 x 3 /4 = 150 lbs.ft for calculating the tube stress we convert this to 150 x 12 = 1800 lbs.inch For a hollow round tube we calculate section module which is $Z = 0.78 (R_o^4 -R_i^4)/R_o$ assuming you have 16 gauge tube with 0.065 inch walls, Z=0.1838 . ...

4

Re-tooling and re-equipping a factory to use a different metal can be very expensive. If the required rate of return from re-tooling/re-equipping cannot be achieved be it simply isn't done. The production rate from some utensil manufacturers may be low and the profit margins small resulting in no major new investing in changing to other metals and re-...

4

Yes it is but there a a few things you need to watch out for. You will need to allow enough excess material for any surfaces which need to be machined subsequent to casting. All castings shrink somewhat so the pattern needs to be a some percentage larger than the finished casting needs to be. Its not uncommon for castings to have internal voids which ...

4

Aluminum sections are extruded from billets heated to 800-925F under high pressure and then pushed through a die. During the entire process temperature is carefully controlled, because depending on the aluminum alloy and performance expected heat stages at the beginning and exit out of die are crucial. here is the diagram of the extrusion machine.

4

The tube is sealed in the following manner: The aluminum from which the tube is formed is laminated or otherwise coated with a thin layer of plastic on its inside, which is easily heat-fused together and which thereby seals off the material inside from oxygen on the outside. The outer surface is also typically laminated or otherwise coated with another type ...

4

My reputation is too low to comment so I'll give some pointers in an answer :) Looking at your design your structures weak points are the areas where the plate and the sensors interface, especially the ones in the corners. This is because you have a very long lever from your load to the feet of your sensors and a very small contact area between the sensor ...

4

When Zeppelins were designed, only non-sparking materials were allowed for them so the hydrogen gas that invariably seeps from the gas bags would not find an ignition source. Steel did not qualify. But this is admittedly a rare example. The other answers which mention the second moment of inertia are spot-on, though. If you build a load-carrying shell you ...

4

Galvanic Compatibility Often when design requires that dissimilar metals come in contact, the galvanic compatibility is managed by finishes and plating. The finishing and plating selected facilitate the dissimilar materials being in contact and protect the base materials from corrosion. For harsh environments, such as outdoors, high humidity, and salt ...

3

For a one-off structure swaging or flaring tube is probably a bit of a long way round to do it. There are actually quite a few off the shelf solutions for joining tube, an example at random Something else to consider is that, for something which is disassembled and moved about a lot, if your system relies on one tube fitting inside another then and damage ...

3

In your situation (as long as you don't actually intend to use the thing!) 6061-T6 will be just fine. The main reason to pick it is that many more product forms are available in it than most other alloys, and it is relatively inexpensive. It is one of the strongest among the weldable aluminum alloys and very easy to machine (as most aluminum is.) The one ...

3

I'm guessing that shipping cost could be a reason. For a pallet (or several) of utensils, shaving a few percent weight off of each one could amount to a significant savings in shipping cost, especially if the trade route is between China and Europe or North/South America.

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