The company I recently started at has always used Struers, but I’ve started looking into it and their prices are HIGHWAY ROBBERY! I get that they like to say they’re “the best”, but I really don’t buy it. I’ve used Buehler, Pace, Allied, and METSUCO. I’ve never had a real quality issue with any of these companies. I’m considering suggesting that we should start phasing out the Struers consumables. I will say, I do like their polishing “pads”. Currently been using the same MD Piano for course grinding, and MD Allegro for 9um polish for almost a year and they’re still in great condition. Does anyone use Struers pads with non-Struers consumables? Of course, Struers suggests it won’t work well, but I don’t buy it. The pre-mixed diamond suspension/lubricant (DiaPro) feels like such a hoax. Is there any downside to making my own premix with a cheaper suspension and lubricant, or even just manually dosing. I’ve always done it that way prior to this job, and I never had any real problems with it. We prep and polish maybe 5-10 samples a week. Opinions, comments, and recommendations welcome here.

I have a toilet that all the chrome fittings have become pitted. The tap (faucet) has the least pitting but it is perhaps the best quality, thickest plate. This as happened over about 6 years but seems to have become quicker and more prevelent in last six months. Don't believe it's to do with cleaning products as 2 other toilets in the house are cleaned with the same and no problems. There is no window and the ventilation is a fan the runs when room in use and 20 minutes after. It is also strange that the white gloss paintwork yellows quite quickly compared to any other in the house. Google it but no real answers

Hello! I'm a mechanical engineering student looking to learn more about the subject for my research proposal for grad school. What do you guys recommend I read after finishing Callister's book for foundational knowledge?

Off the wall thought here... I have a single 17-4PH stainless part here in H1150 condition. Due to some in service wear issues, and inability to solution anneal, then age to H900 (due to distorsion concerns), we're left looking at options to nitride the part., specifically only a bore up the middle.

I'm aware gas nitriding 17-4PH isn't suitable, due the passivation layer preventing diffusion of the nitrogen into the steel. However, I'm also aware of chemical activation methods that allow you to gas nitride.

I'm trying to avoid plasma nitride due to the very high minimum load charge for a single part...

So, here's my thought - we have a variety of flex hones, in the right size - could we do a very quick, dry honing of the bore to remove the few nm of the passivation layer, blow out with compressed air - and straight into nitriding?

I found this paper mentions grinding just prior - but no more details.

https://pmc.ncbi.nlm.nih.gov/articles/PMC8838025/

I think the question I really don't know how to answer, is how long do you get between activation, and having to start the nitriding...

Is there a way to identify series 300 steel vs series 17-4? I have a bunch of gun mounts that are supposedly different materials that I need to differentiate between, but all the label plates fell off.

Hello. I'm currently deciding on a topic for my master's research proposal. One topic that caught my interest were superalloys. I'm getting my master's to hopefully get into R&D so job prospects are important for me. I wanna ask if there are other uses or industries that use superalloys aside from aerospace?

Is it possible to ID the metal from photos alone? The discoloring seems pretty distinct. Thank you in advance for your expertise and insight. On this subject I have none! Cheers

I'm having issues with spring steel 52SiCrNi5. We make special expansion chucks as in the photo where a ponty shaft (in red) push from inside the chuck and makes it expand. The problem is that I'm trying to make it with spring steel to make it more durable but the part breaks almost immediately. What am I doing wrong? Could it be an issue with hardening (this process is made by a third supplier).

Hi everyone,

In my spare time I've been making colored precious metal intermetallics, but I'm having trouble with PdIn. According to everything I read it's supposed to be a purplish pink but all of my attempts at synthesis have left me with a gray blob with a slightly colored center (see image).

My attempts have involved using an arc melting set up where Pd and In are placed on a water cooled copper hearth and hit with an electrical arc to melt. The melting takes place in a large bell jar filled with argon (after evacuating and flushing with argon several times) and only after melting a piece of zirconium to take up more oxygen remaining in the atmosphere.

Does anyone know what might be preventing me from getting the PdIn phase and color? Am I getting things too hot? Is it a matter of annealing?

Thanks!

Pic - https://imgur.com/a/4i5xSDD

Looking to make Ga into beads about 0.2 grams, I have a way to drop the gallium into a size that is about that mass but the gallium isn't forming a solid. The solution is about 10% Hcl, how can I help the solid form more readily?

Would the continuous heating and cooling lead to any kind of useful properties like hardness, ductility, sheen, etc? Specifically for iron/steel or bronze

Hi has anyone studied with Iom3 (institute of materials, minerals and mining)? My husband is keen on the online metallurgy diploma but it doesn't have a lot of information online about how the course works and it is a lot of money to take a risk on it. Just wondering if anyone has any feedback/can vouch for them, thanks!

Having a hard time finding it on the net, How did they mine iron , copper , tin , gold etc

The internet says it’s 1000+ to find any of these metals so what humans just got a pickaxe and mined that deep is it that possible ? How did they know if there’s any metals to begin with

Could anyone explain how this might have happened?

I was working with 5160 High Carbon Steel and was hammering a guard into place. When I tried to hammer it back out, the steel completely broke.

There were other factors at play, but I’m trying to understand what could have caused this. Any insights?

Hi everyone,I hope this is the right section to ask. I've made a grill to use over my barbecue and outdoor camp fire,I've used a stainless steel sheet of 3mm thickness,with some holes and cutout for flame to cook. I've lightly polished It with a flap disk,now I was thinking,is It safe to cook on It? The first piece of bread tasted a little bit metallic,even after a good cleaning and burning,I don't know what can happen under direct flame

I was drilling through a screw, and wiped it with chlorox bleach soaked cotton shop towel beforehand, and no matter how hard I drilled, it just wouldn’t work. So, did chlorox bleach made the steel screw harder to drill? Thank you

Hey everybody, wanted to make one last post about aluminum etching without HF since nobody has pictures of what it looks like. This is for science and posterity.

This was using 25% nitric acid heated to ~70 C for a 6061 Al sample. ASTM seems to undershoot the time quite a bit, ASTM E407 said 40 seconds and this was 3+ minutes.

All in all, I think this is way better than the last post I had with the phosphoric acid. A big part of it is likely there’s way less smut with the nitric method so it’s a lot easier to see everything. Is it going to go in a journal or give you perfect grain size calculations or anything? No. But it still works well enough to see the elongated structures that give you exfoliation susceptibility and decent general structure. I also just felt empty inside sending out a report without a microstructure, so satisfies that inner desire as well.

Also, side note, for anyone who knows exfoliation really well, how come in this sample there’s preferential corrosion along both the really elongated grains and in the more equiaxed regions where all the precipitates are lined up? This is most likely a galvanic issue, as they have iron and copper depositing out here, so I was wondering if that’s why it looks mixed rather than only targeting the elongated layers in the microstructure.

Found in the wall of a house from the 1910s My first thought was lead, but this stuff is magnetic. Is it just straight up iron? I doubted that because it doesn’t have the usual red iron dust. It feels very soft I could just about crumple it into a ball if I had gloves on. My guess is nickel because of the tarnish.

Hi!

I just got a job as a metallurgy lab tech! The company analyses mining samples.

Background is in medical and pharmaceutical science, master's level.

Anyone got any textbook recommendations so I can read up a bit before starting? Really wanting to make a go at a career in metallurgy.

Was going to ask my new boss, but decided not to ask to not come across as a total nerd.

There was a recent post that was deleted that showed yellow deposits on engine exhaust parts. These deposits are also found on turbines, boilers and high temperature test equipment.(edit to remove corrupt link)

https://ln5.sync.com/dl/872691400#293cgsqt-3qibpwkh-4qui2sed-cy7yj7zg

Some people may not be aware of what these deposits are. As awareness of this issue has increased in the last few years.

The earliest reference I have is from 1990, in boiler applications.

https://en.harmfuldust.com/_files/ugd/d7b443_36eda9716c194ccbb47acbd6b06deb87.pdf?index=true

This became more widely known in the Energy industry in 2018/2019.

https://en.harmfuldust.com/_files/ugd/d7b443_0c0e29e8448b48ff95f0dfe6dbddfc1b.pdf

And on combustion engines by 2021

https://www.zeppelin.com/content/dam/zeppelin/power-systems/download-neu/downloads-en/service/Caterpillar_Technical_Bulletin_Chromium6.pdf

https://www.energysafetycanada.com/Attachments/DownloadResource?attachmentGuid=1801a7a2-d4b6-4dea-b6b1-1ba4cd6480a7&open=True

These deposits are chromates (typically calcium or sodium or potassium chromate).These CrVI salts are carcinogenic. These deposits also form on high temperature test equipment containing alloy steels or nickel alloys and materials containing alkali metal or alkali earth compounds. This includes most refractory materials and many high temperature thread lubricants.

If your high temperature equipment or refractory has acquired a yellow deposit take appropriate precautions.

Test strips and swabs for CrVI are widely available.

Solutions of citric acid or citric/ascorbic acid may be used as part of a procedure to neutralise contaminated parts. (edit for spelling)

Hello! I don't know if this is the right subreddit (If it's not, can someone tell me which one is?) But I'm curious if it's feasible to calculate the properties of an alloy made of the following composition:

25% Tungsten

20% Rhenium

12% Cobalt

15% Tantalum

8% Hafnium

10% Zirconium

10% Chromium

Specifically, I'm interested in the potential density, melting point, hardness, and any potential uses for this alloy.
Is it even possible to create such an alloy?
What are the challenges in making it?
How might it compare to existing alloys in terms of performance?
Roughly how expensive would this be to produce?
Any insight into its applications, such as where this might be useful, would be greatly appreciated!

Been following the textbook method for a while but not getting results.

Thanks in advance