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18 votes

Do "non-iron steels" exist?

Steel is defined as an alloy of iron and carbon; there is no such thing as a non-ferrous steel. If you alloy some other metal with carbon, it becomes something other than steel. Looking for a steel ...
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15 votes
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Unknown metal-piece connected to the case of an iPod Nano 2

It's a naked piezoelectric buzzer. Some piezoelectric crystal grown on a metal circle are the active part and the bottom contact glued on the back cover. The top is then metallised to get the second ...
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11 votes
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Galvanized Steel (Zinc Plated Steel) vs Stainless Steel

Stainless steel can be used up to temperatures of about 1000C. The corrosion resistance of zinc plating decreases rapidly above 100C, and embrittlement can occur above 500C. Zinc plating has lower ...
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11 votes

Why does corrosion take place at certain stressed regions?

One of the mechanism that affect corrosion is known in the literature as Stress Corrosion Cracking (SCC). The idea is that tensile stressed regions are prone to crack development. Crack development ...
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11 votes
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What kind of metal are eye glasses frames made from?

There are many different materials that can be used for modern eyewear. Based on the following table (I put it together from online searches, its not from a single site, although the content is ...
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10 votes
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Is this railway carriage side likely made of single metal sheet?

Is it indeed possible Yes and reasonable to craft a carriage side of such large single sheet It can be reasonable, but typically isn't. To form an entire side of the carriage from one sheet of ...
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  • 1,106
8 votes

What would be a practical way for removing thousands of padlocks from valuable bridge railings?

Just do it Since the primary requirement is to not harm the existing structure, anything that is done will have to be manual. Humans are good about dealing with varying conditions. Each lock type, ...
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  • 10.6k
8 votes
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Material selection for weight scale

Which of the following materials will be most suitable to manufacture the disc for the stiffest/strongest possible part. It seems that you need a material that will transform a non-uniform load into ...
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  • 3,587
8 votes

Is this railway carriage side likely made of single metal sheet?

It's possible, aluminum sheeting comes in large rolls; You take one that is wide enough and you can cut out a single sheet long enough for the length of the carriage. It's probably attached to the ...
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8 votes

Why not build container ships from plastic?

In short, because steel is less expensive on a strength per dollar basis of anything else, and for large structures, it's less expensive to work, again on a strength per dollar basis. That's why ...
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7 votes
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How can I finish a round hole so it has 90 degree corners (flat bottom)?

You are likely referring to a counterbore hole, which may be drilled using a bit of the same name. Alternately, if you can't find a bit of the appropriate dimensions, it may be possible to remove the ...
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  • 3,971
7 votes
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Do "non-iron steels" exist?

Iron and carbon have an interaction which make them different from most engineering alloys. This is to do with both the relative size of C and Fe atoms and their chemistry. Carbon atoms are just the ...
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7 votes

What are typical forging loads?

Short answer Forging loads are dependent on total deformation and die type in addition to temperature. So that kind of table is not possible. But you can check flow stress curves such as given below ...
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7 votes

How metal fittings seal connection without rubber gaskets?

The common pipe threads that are used in buildings for water and gas are tapered threads. The thread is cut on the cone rather than cylinder. In the US, these threads are called National Pipe Thread ...
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  • 1,045
7 votes

Why not build container ships from plastic?

Anything is possible and lowering the lightship weight (LS) of ships will save fuel, but the key issue would be any change must not reduce the seaworthiness of ships. This question is very broad. ...
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6 votes

Metal spring thermal expansion

Assuming the spring is not fully compressed/bottomed out, it doesn't really matter if the spring material is expanding or not because it's a spring - it will deform to fill the space between the coils....
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  • 3,525
6 votes
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Why are car bodies not made of titanium?

The bulk price of titanium doesn't tell the whole story. A big chunk of the cost of titanium parts is down to the fact that it is significantly more costly to make things out of titanium than steel. ...
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6 votes
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Purpose and name of fine pitch marks on a cast metal part

these are part-tracking marks. they indicate which cavity in the mold the part was cast from, in which mold set, in what molding machine, in what year, month, day and shift. this way, a part that ...
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5 votes

How metal fittings seal connection without rubber gaskets?

In addition to tapered threads for creating seals, there are Compression Fittings which use a matching male and female mating low angle taper to create a sealing surface. When properly torqued, they ...
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  • 1,578
5 votes
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How do I use this " Low-Density, High-Hardness, High-entropy Alloy" to make a good shortsword?

As a HEMA practitioner and a physicist, I can tell you that different swords need different properties and it is unlikely one material will be the end-all for a sword material. Depending on the sword, ...
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5 votes
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Is it necessary to preheat an investment casting mould when working in a vacuum?

Convection, Conduction, Radiation Of the three modes of heat transfer, only one is affected by the vacuum. As you noted in your question, gaseous convection should be eliminated. That being said, the ...
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5 votes

Strongest brazing materials for titanium?

To give at least some context to this. Titanium is generally considered 'exotic' for welding purposes as it is quite sensitive to both temperature change and contamination by atmospheric gasses, even ...
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5 votes
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Strechable object that can transfer current

First of all, with your 4 inch distance, the propagation time wouldn't be 0.1 seconds. It would be 0.000 000 000 339 seconds. Measuring such short time differences is a significant ...
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  • 1,835
5 votes
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Why did the Soviet Alfa-class submarines have a titanium hull?

the former soviet union had plentiful stores of titanium on hand, so its expense was not an issue. Being nonmagnetic, a titanium hull would be more difficult to detect with magnetometers. Note ...
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4 votes
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Would a T-800 with a gold skeleton deform under stress?

The following table gives some of the material properties of four metals: gold, aluminium, titanium and iron. ...
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  • 9,382
4 votes
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How small can you get a stream of molten steel to be at low pressure?

Making a nozzle with that long and thin of a hole is not feasible, but you could make a larger hole behind it and just have the last 3mm be 0.6mm in diameter. This would be feasible in a ceramic, but ...
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  • 1,295
4 votes

Difference between Precipitation Hardening and Tempered Martensite

Summary: Both processes depend on relative solubility of solute between high and low temperature solvent phases. How each process proceeds at sub-microscopic scale is very different. Precipitation ...
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  • 3,971
4 votes

What's the difference between tempering and aging?

Although the time and temperatures may be the same, different things are happening. Tempering generally reduces hardness/strength, but improves toughness. Aging martensite is done for a group of ...
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  • 5,720
4 votes

How to create an airtight connection between Stainless Steel and PTFE?

You're going to struggle to get a reliable gas tight fit with that design. For a start it would be better if the two connections were separate so they aren't fighting against each other in terms of ...
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4 votes
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What are these metal cylinders often found in the streets of London?

These containers are nitrous oxide canisters https://www.talktofrank.com/drug/nitrous-oxide https://en.wikipedia.org/wiki/Recreational_use_of_nitrous_oxide
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