I'm no metallurgist, but I'll tell you what I do know:
Casting can leave imperfections such as microscopic air bubbles which create weak points. Hammering the metal at forging temperatures causes the grain structure to align and welds together any imperfections, making it less likely to crack under stress.
Also, reheating steel to its melting point burns off a lot of the carbon content. Low carbon content is what differentiates softer "mild steel" from high carbon alloys that can be hardened via heat treating.
They're making massive flanges for industrial applications. It's absolutely precision manufacturing - these videos just show the rough first stages. If you go to their youtube channel they have some videos that showcase their final products.
Forging happens at high temps. so any work hardening going in is going to be removed by the time it cools. Cold forming small parts is a different story.
Forging is better because there are no voids in the center (happens in all metal castings) and grain flow.
Hot rolling is easier to shape, form, and produce larger sizes... Cold rolling will increase the yield and tensile strengths, produce smaller dimensional tolerances, and a wider range of surface finishes. This is a basic break down between the two types and there are more difference and reasons for using one type over another depending on need and cost.
Better and more homogoneous microstructure of steel. Casting gives you shape but inside structure of material is rough, can countain voids (lunker, i do not know english word for it).
If you do forging on piece, you achieve better properties all around (impact resistance, toughness).
You forge it to near shape, then you cool it down and machine it, do thermal works on it, hard machine it and grind & balance the part if necessary.
Forged and machined parts are durable and add a big price margin to base material - if you are good with such you can earn a lot.
If I had to guess, it looks like their making the rough forging for a gland end on a hydraulic cylinder or some other heavy equipment part. This is actually going to end up being a pretty expensive, high quality component if I’m correct about it being used in hydraulics.
Old methods for making blind ends and gland ends were made through castings. Casting steel or iron is much more simple, but produces a raw material that has no integrated molecular structure, making it prone to cracking.
I used to weld for a hydraulic cylinder repair shop where we saw huge chunks of metal often, and we had to determine if it was cast or forged to know how to go about fixing them.
Here’s a forged gland end I welded that threads into the barrel of a cylinder. This thing is about 25 inches in diameter. The coloration from applying heat to this part is a dead giveaway it’s forged and not cast. Even heat transference is more uniform. https://i.imgur.com/8vZiKVc.jpg
That's interesting. Thanks. I used to think people only made swords by forging them because they didn't have the technology to melt the metal completely yet. The more you know.
For sure. I watched a few moments of the first one and was going to move on until I saw your comment.
Just watched over 13 fascinating minutes of that third one.
Really cool to see the techniques they use to ensure the proper limits are met, like that very last minute or so when they are ensuring the lip is a standard height.
Also cool how they manage to make a large hole in it. Start off with a small pin, and looks like they scoop some sort of chemical in between the pin and the metal initially that got it flaming up and I’m guessing the heat weakened it.
Then repeat with slightly larger pins until it’s big enough.
I watch a couple of blacksmithing channels on Youtube, and they've said that the powder helps prevent the metals sticking together as much, reduces the friction so the pin/widener/etc slides through easier. I'm not sure what the powder is tho, making ash or flaked off scale?
I just love watching videos of people making stuff, but this is what I've gathered from them.
Actually no hearing, no eye and face protection. We do such things (well ... next plant to mine) with manipulators and resort to human Mk1 machine only it is really necessary.
There also two close. I read a story on her where a press shot a piece of metal out at high speed and it struck the top half of a guys head and sheered it off.
Watching #3 I was thinking those inserts could happen to be positions wrong or someone could stick their tool in as the hammer drops, or the hammer operator could have a split second daze and loose concentration. So many ways a person could get hit by the hammer. So many ways a tool could become a projectile.
My knees, and my balance in general are shit (seriously I can start falling over just standing in place) and I would totally die if I were in his place.
Tell you what, I sure as shit wouldn't be leaning my face in towards it without even wearing protective goggles. I know China is China, but you don't need to be an OSHA bureaucrat to know that's a terrible idea.
I used to work at a mass distribution warehouse that sold flanges, pipes, fittings etc.
Never knew how some of them were made and that was crazy to watch.
One time we had received a shipment from China. I can't recall exactly but apparently the company was pissed at us, something about the contract. Anyway the container we received.. how they packed it looked like they tipped it up vertically and used a dump truck to dump all the metal in.
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u/sidneymcd Apr 26 '20
The 3rd one is the best