r/metallurgy

Image 1 — Titanium corrosion on fasteners.
Image 2 — Titanium corrosion on fasteners.
Image 3 — Titanium corrosion on fasteners.

Titanium corrosion on fasteners.

I’ve had a box of titanium fasteners sitting in a cardboard box for about a year. I bought them to use on an atv. When I get a spare bolt today from the box I noticed a few of the bolts and nuts had turned a dull gray almost like they had been sandblasted. And some looked like they have actually corroded.

Box has been in my garage and not exposed to water. Any ideas what is going on? There is a few aluminum nuts in the box as well could that be the problem?

u/mcantando — 4 days ago

Snapped my knife and it had brown corrosion marks at top of the break

Hi just snapped my knife and it had these marks at the top of the knife I presume this is due to a manufacturing defect. The knife is made from X50CrMoV15. The company that makes it offers free replacements if it's from a manufacturing defect and just after opinions if it is. Thanks.

u/Jimeh2020 — 4 days ago
▲ 257 r/metallurgy+2 crossposts

Materials scientists develop ductile and scalable 3 GPa (435 ksi) steel via a hierarchical microstructural architecture

nature.com
u/505engineer — 12 days ago

Making steel brittle | Designing an experiment to show for students in history class

Hey all, I'm new to this sub! Looking for some guidance, since I started researching the topic and it's a bit confusing. I work in engineering education and this semester our students are taking a course called "6 inventions that changed the world." Among those inventions is steel, as a material, how it influenced the civilization and how incredibly important it has been since.

Our students are engineers so even this history class is supposed to include science/engineering basics for them to learn. Me and my team really wanted to make a cool demonstration for them and came up with the following experiment: taking a steel rod and heating it with a blowtorch (?) until it's glowing hot, then dipping in water. As far as I understand, it must become brittle if left without further heat treatment. We break it it half to demonstrate how brittle it's become and then repeat the procedure but after cooling in water we heat it again and cool slowly, in sand for example, and then try to break it again to reveal that it is much more ductile now.

I would like to get some feedback from people who have experience with this. I'm also not entirely sure it will work the way I described, so I would appreciate critique. Thanks a bunch everyone!

reddit.com
u/ElectronicDegree4380 — 11 days ago
▲ 17 r/metallurgy+1 crossposts

Eisen Relief mit Korrosion

Hallo Metallurgie Fans, ich hab heute dieses Relief gekauft. Ich habe es aufgrund des Gewichts und des Ausssehen sowie der Art der Korrosion als Eisen Relief interpretiert. Es ist wahrscheinlich kein Zink und definitiv kein Kupfer.

Könnt ihr mir helfen, einen Weg zu finden, die Korrosion zu entfernen und nachhaltig das gesunde Eisen vor selbiger zu bewahren? Ich möchte dabei die Patina sowie die Details des Reliefs so gut wie möglich erhalten.

Letztes Bild zeigt die Rückseite

u/TraderJoe_strong89 — 9 days ago

Are these pellets made of lead?

My dad gave me a large bin full of these small metal beads that were used to weigh down his standing floor speakers. I'm trying to figure out if they are made of lead. As far as I can tell, they are not magnetic (which I think is a bad sign). Is there anything I should do to test them? If they are lead, should I replace them, or is it safe to keep lead pellets in a contained space like the interior of a speaker stand?

u/Puzzleheaded_Two6012 — 11 days ago

After steel is quench hardened, does it slowly lose its hardness over time at ambient conditions?

As I understand it, when steel is quenched it freezes the harder austenite form that steel takes above a critical temperature and prevents it from reverting back to the softer pearlite or ferrite form.

My question is, would a piece of hardened steel slowly revert back to pearlite/ferrite form over a long enough timespan at ambient temperatures, lets say over several thousand years?

reddit.com
u/War_Hymn — 11 days ago

How do you find good project ideas without it being just a gimmick to fill your resume?

I'm currently doing B.Tech degree in Metallurgical and Materials Engineering. I'm in 2nd Yr. The issue I'm facing while searching for projects is I find a lot of ideas but I'm unable to filter out which is actually useful or interesting and good to go with and which are just resume fillers.

For example, right now I had an idea to make a Phase Diagram Analyser that would give the phase composition and phase %age at certain temperature for alloys and all but idk if its useful to invest time after that or its just not impressive at all. Similar thoughts for another one I thought to build a device that can measure the thermal conductivity of materials but again there are already a lot of them, will it be of any use if i build one as a project?

reddit.com
u/Independent-Rip7737 — 11 days ago
▲ 2 r/metallurgy+1 crossposts

Vertical Crack in My Cast Iron Septic Pipe

Hi Everyone,
I’m seeking advice on repairing a two-foot hairline crack without replacing the entire line, which would require opening a tiled bathroom wall and possibly other, unanticipated work.
My plumber suggests that he wire brush the crack and fill and coat it with silicone and then address the issue again if it fails in the future. I’m going with his suggestion but wonder if also adding pipe clamps just above and below the crack would possibly help to prevent the crack from going further. The crack starts vertically at its top and ends in a short horizontal tail at its bottom.
Also, could installing pipe clamps in intervals along the crack help prevent it from widening?
Any opinions would be appreciated. Thank you for reading this.

reddit.com
u/OtherwiseTax7928 — 11 days ago