1074 steel attempts log

I got two filaments with our first order, the first was copper and now that the roll is almost used up I’m trying 1074 steel. first impressions:

1: The filament is way more brittle. With copper I just have to be careful about sudden bends and curves. With the steel the snapping is just silly. making me do equally silly things like this:

in order to make it easy for the spool to unroll… don’t ask me how long this task took me or the other things I tried first…

In the end, filament still broke during my first few tries, and I found it easiest to just break off small lengths and let them hang loose from the extruder. Of course this means I can only make small parts, but it’s fine for now.

2: It requires much slower printing speeds than copper. random uneducated guess: it has a higher proportion of PLA than copper to get it to acceptable bending (though I have no clue why the copper PLA would bend more easily anyway) which means that there’s more PLA to stay melted/flow/be impacted by the metal’s high thermal mass. Regardless of the reason, these are what a couple of my first green parts are compared to copper:

That’s at 60-70 percent of the speed, too. I will try printing very slow and maybe a lower temperature and see how that gets me.

3: Sintering is going to be harder, too, for a couple of reasons. A big one is that iron is just more easily oxidized than copper, and then that oxide layer isn’t as protective. And it’s just plain carbon steel, and the amount of carbon is pretty important to what kind of steel it is. And my method of reducing oxygen is to throw it in with a bunch of carbon…

For my first go I got really lazy and debound it under copper conditions because I was doing those at the same time, so 100F peak temperature less. I then sintered at a more direct profile than recommended, so first just 5 hour ramp to 1100 C and then two hours to the peak sintering temperature, the same 3 hour soak temperature, and then the like 6 hour cooldown phase to 600 C.

My carbon was moooostly gone, hard to tell since it was reused and it doesn’t go completely white when it’s used up. At first the part looked really good, in that it was solid (very light feeling) and held its shape! dropped it a couple times and I swear I could hear a bit of a clank… after wire brushing:

image

So held its shape completely. But when I tried to pull on it it went snap, boo!

It almost looks blue/purple inside.

magnification with both inside and outside in view:

It lost 10% of its weight and shrank much less than you would expect.

Next time I’ll try all recommended settings and heap on more carbon, too.

Very cool writeup!
Thought to make something similar to fit into the spool but went the filawarmer route first.
If you put your insert on thingieverse or have an stl to share throw it this guy’s way :wink:

Hi,
May I ask why the amount of carbon is important to steel? And why increase the amount of carbon?
Thank you.

I actually tried to fit it into the spool as you mentioned at first, and spent an hour cutting out the right sized hole to squeeze it in there… then realizing that the whole point of the bolts on the roll was it came apart easily… then realizing that the bearing was just a bit undersized… then realizing I couldn’t find the hot glue gun so I used a soldering iron… sheesh.

I actually just used it because it was already lying around the lab but I think it is this this model: Large "Print-in-place" Ball Bearing (Ø145mm) by barspin - Thingiverse

I would recommend scaling it a bit so you can just stick it inside with a bit of tape unlike me!

it is a really complicated subject why carbon is important to the property of steel. That’s another way of saying I’m not an expert but for instance, more carbon increases the hardness while making it more brittle. One thing they’ll do to get the best of both worlds in industry is carefully increase the carbon content of just the surface of the metal. This makes it resistant to scratching while leaving the core soft to absorb impact energy. I just learned this fact last night, so don’t take my word for it!

Thanks! Hopefully won’t need it with the warmer… but with my luck I’ll be printing that bearing soon

Of course, I can’t help but think you might be able to loosen something up on your extruder too to reduce the grip… If it worked before, I just feel like there’s no reason to have to add another variable (filawarmer) if you don’t have to

Hmm… I thought that 1074 was just plain carbon steel, but it’s actually stainless steel. So much for solving all my problems by buying stainless in the future!

Thanks for the information,
Have you used the suggested settings Sintering Refractory Ballast and sintering carbon they provided?

I used aluminum refractory instead of the one specifically for steel. I did use carbon but maybe not enough. I followed the settings mostly but with a 100 less degree F peak debinding temperature (I was doing copper parts at the same time.) I think I’ll start my crappy little parts tomorrow, giving them a bit more attention. Tried again to print today but didn’t get far before breaking.

Looking forward to your sharing.How do you know if carbon is enough?
And today I am going to the second times sintering for the ss 316L.I will show the result here
when finished.

Followed the debinding and sintering temperatures precisely this time. Note that I was confused; copper actually is debound at a higher temperature than steel. This time I added more carbon, too.

When I was done I feel like there still wasn’t much carbon leftover after sintering, whereas with copper there’s usually plenty. Temperature and long cooling times could definitely be a factor. Also, the aluminum oxide held together more solidly than with copper. Just little details, but they all have some kind of reason.

Anyway, pics of what came out this time:

Cracked head, never a problem with copper. Not even going to bother trying to process this one.

Cube maybe shrunk just a little bit, not as much as copper, even though the steel has a lower metal content (again, why is copper more bendy even though it has less plastic? @bradley)

Here’s what it looks like under scope, same greenish skin as before:

I polished the bottom and I mean, it got shiny. It’s cool that it’s magnetic too.

But without a way to clear off just the oxide, I thought maybe I’d try ‘polishing’ it in the planetary mill with some pieces of copper:

…bad idea. That little chunk was what survived. The rest crushed into powder within 20 minutes. By copper.

So: Absurdly embrittled steel, or just a block of rust? I vote for rust.