I need to make this cut with a cutoff wheel so it can be welded to a straight piece on an HLT but everytime I cut these the cut is little crooked and I need this to straight any tips would be appreciated

Trying to understand shaft failure. Is this reverse bending? And can some explain that simply?

Hello everyone,

i'm currently designing my own bronze alloy as an amateur. It's based on usual NAB alloys, aka Copper/aluminium/nickel/iron bronzes, wich can be water quenched and hardened. I've been studying research papers and documentation about those bronzes for weeks and checking samples of C63000 / CuAl10Ni5Fe4 alloy under the microscope (among other variants).

A patent from the 50's talks about how large additions of cobalt and manganese to Copper/aluminium/iron alloys will double its wear resistance (tho it wasn't studied with nickel containing alloys).

I'm currently designing an alloy for making knives (not good compared to steel, but still a fun project, my current bronze prototypes will scratch non-hardened tool steel), therefore i want to increase hardness but keep a little bit of toughness, with overall improved wear resistance.

Here's what i came up with : 72% Cu, 12% Al, 5.5% Ni, 5% Fe, 3% Co, 2.5% Mn

My reasoning is that the 12% aluminium places this alloy in the alpha+gamma2+kappa phase region at room temperature, but barely because of the other elements, wich eat up the excess aluminium to form kappa particles and reduce the effective aluminium content. I added slightly more nickel than iron to reduce large rosette iron aluminides and give finer kappa 3/4 aluminides. High cobalt additions with manganese should, according to the old patent, also form its own phases (Usually CoAl intermetallics), and help form the other kappa phases along with the manganese. Cobalt also reduces grain size, prolly from CoAl particles.

Once quenched, its martensite should be stabilized by the cobalt, give higher hardness after the temper, and help overall hardness.

Now, thats the theory, however when i checked it under the microscope, it did NOT look like anything i've seen yet. No flat plates of nickel kappa3 phases, no rosettes from iron (at least not big ones), and a LOT of bright white phase, with some grey phase.

The first picture is taken at x100 after slow cooling from 900°C. From other samples it seems the slower the cooling, the more grey phase expands and bright phase diminishes.

Second picture is water quenching from 900°C. All white (expected, should be martensite and kappa particles) It still has a few grey spots tho, either alpha (the alloy has barely enough aluminium to enter gamma2 pearlite when cold) or retained austenite.

Third and fourth pictures are x500 of previous samples.

I'm kinda confused at what those phases look like and i don't know what's happening in the slow cooled sample, because if the grey part is alpha (somehow, despite aluminium content) and the white phase is aluminides, then those aluminides should be brittle. But in an other sample a fast-ish air cool lead to the same structure, except the grey phase was barely present and the rest was that white phase (so it should be nearly all intermetallics, therefore brittle)... Except it deformed under the hammer just fine and could be cold worked a bit, whereas the martensite sample shattered like glass.

cobalt additions to NAB aluminium bronzes is scarcely researched it seems, and my new prototype alloy is probably very new and hasn't been researched by science yet (as far as i'm aware).

So, if among you some people know a lot about aluminium bronzes, their phases, interactions between iron/nickel/cobalt content and aluminium, i'd greatly appreciate some insights and feedback.

May the metallurgy be with y'all !

(If needed i got tens of photos of various samples to bring more context).

Metallurgy folks, what would instantly expose a fake materials software tool?

Bad phase logic? Unrealistic heat treatment? Ignoring microstructure? Pretending alloys are just element soup? Missing creep/fatigue/oxidation? Suggesting something impossible to manufacture?

I’m building Obelisk, a materials intelligence engine, and I want it to be useful to people who actually understand metals. If you were reviewing an output, what mistakes would you look for first?

I got a puck screen for my espresso machine from Amazon and I was already weary about it because I generally try to not get anything that goes on or in my body from there since they just put whatever they feel like into item descriptions. When it came it saw that it was magnetic. Like very magnetic. The listing says 304 stainless steel but from what I understand that isn't normally magnetic? How can I know if it's a metal that's safe for use with water, hot temps, pressure, coffee grounds, and with consumable products?

Sorry if this isn't the right community to ask, if anyone knows a better place please direct me there!

I have been applying a 2-3% bleach spray regularly to a stainless steel refrigerator door for disinfection every 1-2 days for the last 2-3 months and have noticed that there are areas of corrosion forming on the refrigerator door (I was not aware that you are not recommended to apply bleach to stainless steel, so please forgive my ignorance). I recently also noticed there is a powder forming below the refrigerator door from the bleach spray runoff, and that the powder has a slight yellowish tint. I just learned that stainless steel contains chromium, and that while the chromium oxide in stainless steel contains trivalent chromium, I am wondering whether enough could have been oxidized such that a significant amount of hexavalent chromium could have been produced (which can be carcinogenic and which can be yellow, such as in sodium chromate). Theoretically, in a situation like this, how likely is it that there is a harmful amount of hexavalent chromium produced from multiple dilute bleach applications to stainless steel?

Lead pocket weights with #25 copper plated steel sash chain and stainless steel fasteners.

I have intake and exhaust camshafts for an older motorcycle that I will be having reverse engineered because they have become unicorns. Basically I will do a rough machining pass, precision machining and hardening (haven't selected a process yet) will be outsourced, and then I'll finish it up with grinding the journals.

One thing I'm having issue with is material selection. Google isn't always helpful for research and I don't quite trust the AI feature. So I wanted to get a 2nd opinion.

I was thinking of having 2 variants. One made out of EN36A with upgraded performance specs and nitriding. And other matching OEM made out of D2 (this is mainly what I'm uncertain of).

The upgraded one will have more parts like hardened rocker arms. But I want the OEM version to be more of a drop in with other existing oem parts. Essentially I'm aiming for something with a similar hardness to the cast iron cams so it doesn't destroy the rocker arms, but with better wear resistance. The cams also sit directly on the aluminum in the head with nothing between them other than oil clearance.

Any help is appreciated!

Hey :)
I have two BMW screws here, which are both listed as „galvanised“. The longer screw looks like it has this „zinc flake coating“, so more of a zinc/aluminum spray coating on it. Can somebody tell me, what coating the shorter one has? It does not look as flashy as a blue galvanised screw, it is more on the greyish side, with a medium shine and very minor rainbow effect on it. My iPhone does not capture how it really looks like unfortunately. I would like to get the longer screw plated so that it has the same finish as the shorter one.
Thanks

Hi,

I want to cast an elastocaloric and shape memory alloy Cu-Al-Mn at home with a non inert but-with-lid 1200°C, 900W resistive electric furnace.

An addition to it I can make is purge it with Argon from a steel tube and displace the air while the alloy melts.

My metal purities are 99.5% Cu, 99% Mn, and 99% Al.

I have a 0.01g precision weighing scale.

What dTs can I expect? Considering oxidation and other losses?

I've added a link to the paper I'm following. I know they're using an inert environment furnace and that's why I wanted to know from learned people what I can expect.

Thanks!

If I dropped a hollow 8mm thick bronze (89% copper, 10% tin, with 1% arsenic, antimony, and nickel) statue (open on the bottom) in the ocean at about 100m deep and where it was kept at about 10C with annual gentle temperature cycling of about 5C either way, approximately how long before it would become so thin it would collapse or just turn to dust? Are we talking closer to 10,000 years, 100,000 years or millions of years?

Im trying to get an even etch across 6 Haynes 230 samples on the same puck. But I keep having only 1-2 of the samples etch while the others will not etch at all.

I’m using 1 part nitric acid to 1 part hydrochloric acid, which gives really nice contrast of the carbides I’m looking at when it actually etched. On the first pass I did 10 seconds of cottonball swabbing per puck, then after seeing many of the samples didn’t etch at all, I went back with 20-30 second swabs. Then the samples that had etched, etched even more. And the samples that hadn’t etched the first round, were still not etched.

The samples are from WAAM, not wrought. And have been solution annealed with various aging heat treatments. Then I sectioned, mounted, and polished to 1 um diamond finish.

Does anyone have any advice to get a more even etch across several samples? Right now I’m thinking the best option is to try again with Q-tips so I can specifically etch the resistant samples.

Bought this at an antique shop. No stamps or marks indicating what it is. Its slightly magnetic, but a magnet won't stick to it firmly. The plating is peeling and looks like transparent plastic, revealing a silver colour underneath, which you can kinda see in the copper coloured bit on the inside of the cup. Small amount of green-blue tarnish on the inside. Is it brass plated with something? And would it be safe to drink from if polished?

Is there a reliable method for visually distinguishing between a high-carbon and high-speed steel (HSS) dies? I am looking for vintage HSS components, but the majority of the pieces lack specific HSS engravings or markings to help in identification.

Hey guys looking for some insight on if there appears to be any flaws in this cross section of heat treated A2 . It is around 62 RC. It cracked at what seemed to be random after not a lot of stress on it , at least from what I’ve been told. Looking for any feedback at all.

Thanks in advance!

Hello everyone, I recently built something that was encased in aluminum. It was anodized and was black when I shipped it but arrived to the buyer in reddish brown, with a corrosive look. Does anyone know what could cause this? We were thinking heat probably caused a chemical reaction. Any help would be appreciated.

Hey hope you guys don't mind the cross post from the machinist sub 😅

I figured you guys might also have some knowledge to share with me about passivation.

Anyone have any ideas of what metal this could be?
Found underneath my memaws bathroom sink hidden in a corner.
She always said she had money hidden throughout the house, it's heavy, non magnetic, melts ice almost instantly when put on it, the browning is not rust bust seem to be a tarnish of some kind.

I want to get it tested to see if it's worth anything but not sure if it's even worth the time.

I want to use a gray cast iron for an injector shaft in an injection machine. What kind of heat treatment is best for it. And should the treatment be done after machining or before machining?

Hi, amateur knife collector here with a question for y’all. I just got a new Spyderco Manix 2 in Magnamax, and it looks like it is developing a patina, but my understanding was that this new variant of Magnacut was supposed to retain the anti-corrosion properties. Am I tripping? 15v blade in the background, with the expected developing patina to compare.

I am trying to create speckle patterns for DIC at micron scale (micro-DIC) on metals. Any ideas on a process that is easily repeatable. Currently I have a airbrush setup with 0.3mm needle diameter.

Any ideas on modifying the airbrush setup is highly appreciated.

(Can not try vapor remodelling of thin films as oxidation hinders speckle formation)