# Tag Info

12

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

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

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 ...

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

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

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 ...

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 ...

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 . ...

5

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 ...

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 ...

4

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 ...

4

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 ...

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 ...

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

Having spent several years in product development at Kitchen-Aid's parent company, I can guarantee that if there were a less expensive way to provide the same function to the consumer, that is how it would be done. They have whole teams of engineers tasked only with cost reduction. The reason that items are marked as "hand wash only" often have more to do ...

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

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-...

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.

3

This is unlikely to work very well. The biggest issue is that you won't get good adhesion between the two surfaces. aluminium has a particularly resilient and inert surface oxide layer so molten aluminium won't just stick to the surface of solid aluminium. Welding it requires an inert atmosphere and reverse polarity current or alternating current to clean ...

3

I used to build structures using the 80/20 aluminum extrusions , I used a mitre saw with a good aluminum cutting blade lubricated with stick wax (or any good cutting fluid). Makes beautiful square cuts with minimal burring. Be careful applying the stick wax to the rotating blade, otherwise your mitre saw will become a finger removing device by default :-(

3

(Short answer below) A phase diagram like the one you posted is to be intended true for a solution(either solid or liquid) of the two components(i.e. Al and Cu). Adding Cu to molten Al does not properly mean to have a solution(the two components must be dispersed in thw whole bath in a uniform way). Also a phase diagram is drawn as a "succession of ...

3

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 ...

2

Steel or aluminum can be made equally strong. Generally aluminum can more easily be designed to have a higher strength to weight ratio because it has the a larger area moment of inertia for a given mass. Like Olin Lanthrop mentioned in the comments, the weakest link will be your connection between the table top and the legs. You can't count on the friction ...

2

Normally the production of specific alloys is a fairly specialised process and they would be bought in as ingots or other stock types from commercial manufacturer rather than being made as part of a manufacturing process. This is as much about the quality control and analysis required to produce a given alloy to a specification as the actual mechanics of ...

2

Beside very cheap products, the only aluminum parts I have found in my kitchen tools are either injected or molded. Why this? Because the fusion point of aluminum is much lower than steel, plain steel molds can be easily used. The opposite is not true and for steel casting, it requires disposable sand molds. Thus, the process of steel casting is more ...

2

I am going to start out by saying that aluminum is a mess. There are too many designations and things that you can do to it after it solidifies. To directly answer your question, what might necessitate an additional round of heat treating is directly affected by the desired final mechanical properties. Each of the designations that you listed is a complete ...

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