Questions tagged [metals]

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What kind of metal are eye glasses frames made from?

I've noticed that prescription eye glasses frames are often made from metal that is quite rigid. It's surprisingly difficult to bend the metal, despite how thin it is. And if it does bend, it doesn't ...
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9 votes
2 answers
172 views

Material selection for weight scale

I am looking to test the FlexiForce sensor in measure force, however for accurate readings the load needs to be disturbed evenly over the sensing area. As such I am having "discs" made to cover the ...
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8 votes
4 answers
3k views

Do "non-iron steels" exist?

There are numerous steel alloys, containing mostly iron, carbon, and some other metals. Generally speaking, we can think of them as if they were some type of steel. My question is: do "non-ferrous ...
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8 votes
2 answers
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Is this railway carriage side likely made of single metal sheet?

A neat image from Wikipedia: Here the railway carriage side looks like it is crafted from a single sheet of metal (if we ignore the doors and the windows and some minor parts like that small thing ...
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8 votes
2 answers
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Unknown metal-piece connected to the case of an iPod Nano 2

I disassembled an iPod Nano 2 yesterday and was surprised to find a round brass-coloured plate glued to the back. I didn't find any mention of it at the teardown over at ifixit.com, as they didn't cut ...
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8 votes
1 answer
426 views

Weldability of Pure Tin

The site states that Tin cannot be welded, but after I made some research, I discovered that tin, when alloyed with copper or used as a protective coating for steel, can be welded. My question is why ...
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7 votes
2 answers
1k views

Metal micro perforation

I'm trying to design a metal surface with micro-perforation for a product and light it from other side with LED, such that the perforated pattern appears only when lit. In my previous prototype, ...
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6 votes
2 answers
7k views

How metal fittings seal connection without rubber gaskets?

I am well familiar with the concept of gasket. From my non-mechanical engineer perspective, I can understand how a standard rubber gasket works in various plumbing ...
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6 votes
2 answers
817 views

How can I finish a round hole so it has 90 degree corners (flat bottom)?

I have a 10 mm depth x 5 cm length 99% Tungsten rod. How can I machine the described hole so that instead of having a bevel from the tip of the main drill-hole bit, it has a perfect 90 degree corner ...
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6 votes
1 answer
988 views

What are typical forging loads?

What are typical forging loads for various metals and configurations? I know that the typical test for a metal is to upset a 0.750" high x 0.500" diameter cylinder to a height of 0.5", but could not ...
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5 votes
2 answers
2k views

Metal spring thermal expansion

I am attempting to figure out why a laser layout tool I have is drifting over time. It was designed with a small adjustment mechanism that relies on a spring to apply pressure to a fulcrum that ...
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5 votes
6 answers
498 views

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

Inspired by this story about Paris authorities ordering removal of thousands of "love lock" padlocks from bridge railings. This is not a DIY SE question because it's not DIY scale in the first place. ...
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5 votes
2 answers
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Difference between Precipitation Hardening and Tempered Martensite

The textbook "Materials Science and Engineering An Introduction" mentions that: "Precipitation hardening and the treating of steel to form tempered martensite are totally different phenomena, even ...
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5 votes
2 answers
311 views

What grade of titanium are "memory titanium" glasses made of?

I've worked with different grades of titanium. Mostly with grade 5, and also grade 1 which is ductile. I know that some glasses are made of titanium and are called "memory titanium", I guess because ...
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5 votes
1 answer
178 views

Optimal size and shape for a steel target?

Problem I'm building a steel target for long-range rifle shooting. For those unfamiliar, the purpose of the steel is to produce a loud "PING" when the bullet strikes the target. It's very fun. Since ...
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4 votes
2 answers
529 views

Why does corrosion take place at certain stressed regions?

Why does certain parts of metal show more corrosion at the place where there is high dislocation density in comparison to the place where the dislocation density is less? I do sincerely feel that this ...
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4 votes
1 answer
168 views

Purpose and name of fine pitch marks on a cast metal part

I have seen this kind of mark on various cast metal parts. This is an image of the base casting of a hard disk drive made by HGST. What are these marks for? What are they called?
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4 votes
1 answer
5k views

Strongest brazing materials for titanium?

What are the strongest brazing materials for titanium? The main materials I would like to use would be copper or silver, in which case I would like to ask which would form a stronger bond with ...
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4 votes
1 answer
195 views

How small can you get a stream of molten steel to be at low pressure?

I'm designing a crucible / extruder, and right now it has a .6mm hole to extrude from. Will this work? A chart with various metals listed would be nice. Pictures: Click to expand
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4 votes
2 answers
99 views

Frequency dependence of electromagnetic shield metal

I know that the effectiveness of metals used for electromagnetic shields heavily depends on the used frequency or frequency range. I could not find a resource in the web (tables or graphs) that give ...
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4 votes
1 answer
334 views

How to calculate the bending resistance of a square metal bar?

I have an old bend/twisted wooden door. It has some character to it so I want to keep it and add square metal bars to straighten it. I have provided a sample drawing of the door and where it is ...
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3 votes
1 answer
2k views

Is it necessary to preheat an investment casting mould when working in a vacuum?

Normally, in investment casting, the mould is preheated before pouring the liquid metal in to reduce thermal shock from rapid cooling. In a vacuum, the heat transfer due to gas convection is reduced ...
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3 votes
1 answer
767 views

How do I use this " Low-Density, High-Hardness, High-entropy Alloy" to make a good shortsword?

Given the information on swords here: When you need to place a great deal of strength into a thin blade, steel remains the best all around choice. Titanium blades will be simultaneously weaker and ...
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3 votes
1 answer
384 views

Can Rotary Friction Welding be used to join metals and ceramics?

Is Rotary Friction Welding a good method to join cylinders of a metal (such as Ti alloy) and a ceramic (such as SiC). I know that Diffusion bonding can be used in such cases. However, it has its own ...
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3 votes
1 answer
167 views

Would a T-800 with a gold skeleton deform under stress?

Over in Programmers chat we were discussing whether a gold skeleton would be feasible. That got me thinking: If I were to build a Terminator (T-800) using pure gold as the endoskeleton, would the ...
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3 votes
1 answer
4k views

Sheet Metal Bending: stuck on calculating the minimum radius required

I'm used to calculate the minimum radius required for bending operations on both aluminum and steel sheets, given the following parameters: https://imgur.com/a/7akHC Problem statement: For a sheet ...
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3 votes
1 answer
389 views

How thick does an aluminium vacuum cylinder have to be?

Take a hollow aluminium cylinder with outer radius $r$ and length $h$, capped with two circular endcaps. How thick does the aluminium have to be, that is what is the inner diameter of the cylinder, ...
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3 votes
1 answer
44 views

Can chemical vapor deposition chambers be used to lay down thick layers of metal?

Can CVD Chambers be used to lay down thick (~1 mm) layers of metal?
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3 votes
4 answers
117 views

The behavior of the stress-strain curve of metal, containing a void

Let's assume that in a metal sample without any dislocation, there is a void. Then we conduct a uniaxial tensile test.
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2 votes
2 answers
297 views

Why did the Soviet Alfa-class submarines have a titanium hull?

My limited knowledge in engineering tells me: Titanium is expensive, stronger and heavier than aluminium, lighter and weaker than high yield steel. The most significant advantage of titanium is the ...
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2 votes
2 answers
164 views

Is there a drill adaptor or attachment tool for cut a metal solid cylinder

I need to cut a 7mm solid Aluminium plug (Non-hollow and non-threaded) to replace a part in my car. Is there a simple drill adapter tool to cut a solid metal cylinder (Plug) from an Aluminium mass ? ...
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2 votes
2 answers
3k views

What's the difference between tempering and aging?

The processes sound really similar; I'm asking with respect to Martensite processing. Essentially the difference between Tempered martensite and Aged martensite for Steels
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2 votes
2 answers
427 views

Which materials can be used to make permanent casting molds for cast iron?

I am interested in comparing the different materials that can be used to make castings of cast irons, and therefore was wondering which material is commonly used/which materials can be used to make ...
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2 votes
2 answers
3k views

Is a metal Prince Rupert's drop possible?

Can a Prince Rupert's drop be made of metal instead of glass?
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2 votes
2 answers
104 views

Heating Sand/Ceramic/Refractory Material under vacuum

In a Vacuum Metallurgy (Casting), a mold needs to be heated (500 to 700 degrees) to reduce thermal shock on the metal surface. Normally, a gas fired oven is employed for such job, but in a vacuum ...
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2 votes
2 answers
94 views

What type of drill bits are these?

https://drive.google.com/file/d/1JPV6dRqB6f__N1eCcmn6QkOStLpVdc-U/view?usp=drivesdk Here's an image for bits Head. https://photos.app.goo.gl/HS8hFqLeWn8jecka7 In the image above (Google Images & ...
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2 votes
1 answer
221 views

What mechanism is available to rotate a metal piece on another metal piece?

I am trying to find some type of mechanism where I can have a smooth but not too stiff rotation between two metal pieces. I was thinking of putting a shoulder screw through the pieces (the pieces will ...
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2 votes
1 answer
304 views

What is the ideal metal sheet thickness used in a 1 tonne atv/tractor dump trailer?

What would the ideal thickness of the dump trailer bed be, so it can withstand loading rock from a height of 1 meter? The spacing of ribs is yet to be decided. The goal is that the trailer be as ...
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2 votes
2 answers
131 views

38CrNiMoAlA: Does it even exist?

I have some plungers made of 38CrNiMoAlA. Their required hardness to be achieved via quenching/tempering is 51 HRC. I've scoured our technical order for heat treatment of steel alloys but the material ...
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2 votes
3 answers
80 views

Support columns inside metal tubing

Does structural metal tubing (e.g., either as HSS, or in space frames, or even motorcycle/bicycle frames) ever come with any small metal rods or columns inside of the tubing itself? While it might ...
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2 votes
2 answers
1k views

Heat treatment processes for ferrous metals

I am trying to find out information about the heat treatment processes of ferrous metals as part of a project which involves making a screwdriver. This includes: Hardening, Annealing, Tempering, ...
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2 votes
1 answer
77 views

Coating gold on to sunglasses lenses?

Recently I have been trying to find out more about the process that is used to coat glasses lenses with gold. I asked about it in another forum last night and I was directed here. I initially thought ...
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2 votes
1 answer
71 views

What paint/spray on material should I use to insulate a metal pole?

I am not entirely sure if this is the correct forum to ask this question so please refer me on if there is a better arena. I am creating a small weather station and I wish to measure soil ...
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2 votes
1 answer
526 views

How to use sample holder on Metallography specimen preparation machine Struers Tegrapol-21

In lab we have Struers Tegrapol-21 grinding and polishing machine. I use it for sample preparation. Usually I put 6 samples at once and prepare them with sample holder. However today I need to prepare ...
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2 votes
0 answers
82 views

What is the Specific Heat of Molten Bronze?

I have sources giving the specific heat capacity of bronze as 382 to 385 J⋅kg⁻¹⋅K⁻¹, or as 435 J⋅kg⁻¹⋅K⁻¹. I'm assuming the variation is due to different alloys being considered, which are not ...
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2 votes
1 answer
168 views

How Can I do punching of 0.22mm in stainless steel sheet (Sheet thickness 0.5mm)

Wanted to press punching of 0.22mm dia (Bottom) and on (top) 0.6mm dia Please suggest how can I make such die?
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1 vote
2 answers
530 views

Why not build container ships from plastic?

This may sound crazy but bear with me. I was thinking about why cargo ships are built from such heavy material as steel, while smaller boats are often made of plastics. I know cargo ships carry a lot ...
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1 vote
1 answer
10k views

Galvanized Steel (Zinc Plated Steel) vs Stainless Steel

Zinc Plating is known for its ability to prevent most corrosion, and it is done by just dipping a metal in hot pool of zinc and letting it cooldown. Meanwhile, stainless steel, an alloy that is ...
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1 vote
6 answers
2k views

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

I have these two parts shown below, the bottom cylindrical part is stainless steel, the rectangular upper piece is PTFE (Teflon). The SS prongs from the lower part need to insert into the holes of the ...
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1 vote
1 answer
126 views

Aluminium Bolt in Titanium Casing: Any Dangers of (Contact-)Corrosion?

Assumed we have a fuel flask that is made of titanium. The bottle will be filled with white gasoline when used. At the bottleneck there is a standardized thread manufactured into the titanium. Are ...
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