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Inclusions in material

JohnEvans

Titanium
Joined
Sep 23, 2009
Location
Phoenix,AZ
Ordered in some 12L14 to make a hub to adapt a Chevy V-8 crank vibabration dampner to a Hot Roded Modle A Ford 4 banger for a friend. Drilled a through hole and bored to size ,turned the 2 dia. on the OD and parted off. The boring cuts were smooth and quiet,didn't notice the issue until after I milled a keyway on the small OD. The inclusion looks like a piece of 3/16 tool stock went into the melt and had a higher melting point so stayed intact. The damage will not affect the use and being it's for a friend he won't care. A regular customer would not be so understanding I fear. The only good thing is that it is on the ID ,on the OD being it's leaded steel I could not build up with weld. NUTS!!!!!
 

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Today at my fulltime job, we had 90 (quantity) 8" diameter by 4" thick cylinder bases rejected by the ultrasound. Inclusions in 80% of them, three different heat numbers.

I always hear that todays materials are getting shitty and shittier, now I'll be saying the same thing.
 
The inclusion looks like a piece of 3/16 tool stock went into the melt

Hey, that's just the way you get back all your carbide inserts that break off and go into the scrap bin, together with the chips.
I think this will become more and more a problem, with the recycling rates.


Nick
 
Yup. Crap in the recycle bin. I try to use stuff out of the scrap bins for fixtures and stuff, but some of the guys where I work will toss a part with a broken drill in there without thinking about it. (don't ask why he breaks drills, he's just an ass)
 
I will state my opinion of 12L14

CRAP

Good for door stops...

Even a crank hub is exposed to water.. which 12L14 is allergic to..

It's so easy to machine they say... So is toilet paper... Nice and soft, so grit can cut seal surface too..

How many crankshafts are 12L14?? head bolts?? connecting rods???

Even a simple pulley hub is subjected to vibration.. And plenty of it...

Adding lead to steel, right up there with, adding water to gasoline...
 
You guys just need to do some fun pressure retaining parts. Then you buy bar that been UT and certified. Castings get X-ray. All that, and you still have porosity and inclusions.

Just had a C5 casting that opened up porosity on finished bore. That a 5% CR 1/2% MO. Heat treat required after weld. So.......weld everything and start over.
JR
 
Ah yes, one more....."Laminated plate"

Lovely when it makes it all the way thru burn, form, weld, anneal, machine,
and then it's discovered in final assembly, or worse, by the customer.
 
i once took a tour of a mini mill or small steel remelter. they made in one day a pile of 2x2 angle 20ft long pile was 20ft wide by 20ft tall.
.
scrap gets melted and additions are made like deoxidizers which help eliminate free oxygen that show as gas bubbles when welding. deoxidizers when they meet oxygen form aluminum oxide and silicon oxide which is basically an abrasive grit in the steel. they try to get the slag which rises to top to pour off. basically it is a critical and fast done operation of send sample to lab make alloy additions wait a bit, pour off slag, pour steel to tundish of holding tank that releases 3 streams of 5x5 square white hot continuous cast that are cut to lengths and immediately rolled to shapes.
........ what do you think happens to less than perfect stuff ?? my guess is it gets sold at a discount and you can bet they don't call it scrap metal but give it a nicer sounding name. Most places that use steel a lot keep track of the "heat" number which is like a lot number , everything in the same batch probably has they same problems.
 
Ordered in some 12L14 to make a hub to adapt a Chevy V-8 crank vibabration dampner to a Hot Roded Modle A Ford 4 banger for a friend. Drilled a through hole and bored to size ,turned the 2 dia. on the OD and parted off. The boring cuts were smooth and quiet,didn't notice the issue until after I milled a keyway on the small OD. The inclusion looks like a piece of 3/16 tool stock went into the melt and had a higher melting point so stayed intact. The damage will not affect the use and being it's for a friend he won't care. A regular customer would not be so understanding I fear. The only good thing is that it is on the ID ,on the OD being it's leaded steel I could not build up with weld. NUTS!!!!!
Maybe I'm blind, but where exactly is the inclusion?
 
Ah yes, one more....."Laminated plate"

Lovely when it makes it all the way thru burn, form, weld, anneal, machine,
and then it's discovered in final assembly, or worse, by the customer.

In the case of the hydralic bases, they went through; burn, machine, weld, machine, weld, and finally got caught at the final machine.

Edited to add: the drill press operator noticed some porosity in a spotface and raised the red flag.

We recently switched to a different supplier for burned blanks because of this very problem with the former suppliers bar stock.
 
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I recycled some 12" 22Lb beam for a deck I built. While drilling the web for cross beams I hit a rolled in inclusion. The steel was at least 25 years old then (1986). Hougen broaches were not cheap then.......

 
TD: It is the internal keyway looking area,that is where whatever it was was living. I had not seen any issues until after I had removed the part from the mill after cutting the external keyway on the smaller OD. I think maybe the clamping pressure in the mill vise deformed the part enough that the piece fell out. One of lifes mysteries I guess. Delivered the part tonight to my friend at a car cruise and got a order for another one from a different friend when he saw it.
 
It happens to the very best we know how to produce and inspect. Had a Titan IV launch being prepared at Cape Canaveral in the 70s with a billion dollar payload on a tight launch window.

The solid rocket boosters were steered by fluid valves that could inject N2O4 (very nasty stuff) into the exit cone of each booster. Twenty four valves per booster, these were very big solid rockets. (look up Titan IV if you're interested) The valves had 17-4 PH pintles, the movable part of the valve that controlled the flow of N204 into the exit cone to deflect the thrust of the rocket to steer the vehicle.

My company manufactured the boosters and steering system.

The last test on the launch pad prior to fueling the steering system (TVC, thrust vector control) with N2O4 was to pressurize the system with helium and look for leaks. Helium is a very small molecule and will find any path out it can. It's also safe and easily detected. First time ever after many launches one valve leaked, a few molecules per minute but detectable and a fail. A mad scramble happened to replace the leaking valve and save the launch window.

The metal that part was made from underwent every most sensitive production process and QC known to man before making the parts. The finished parts went through every QC process again. No cost was spared, the part failed.

The leaky part was found to have a microscopic stringer though over four inches of solid metal, far smaller than might be imagined. It was so small it was beyond detection of our then most sensitive tests. So... better tests were needed and developed.

There is no perfect material, there are only acceptably flawed materials. Knowing what is good enough for the job and least expensive is a fundamental part of engineering.
 
TD: It is the internal keyway looking area,that is where whatever it was was living. I had not seen any issues until after I had removed the part from the mill after cutting the external keyway on the smaller OD. I think maybe the clamping pressure in the mill vise deformed the part enough that the piece fell out. One of lifes mysteries I guess. Delivered the part tonight to my friend at a car cruise and got a order for another one from a different friend when he saw it.
So, you did not cut the internal keyway?
 
I have to agree that raw materals, be it steel, copper, aluminum or whatever, are getting worse and worse due to several cycles of recycling. Yesterday I was turning down a piece of one inch diameter 1018 to 0.75 and ran into two hard spots in less than three inches that I thought I was going to have to put on the grinder to get through -- probably the chrome off a 1956 Chevy bumper!
 
TD: No, I had nothing to do with that apparent keyway. Don't have any equipment to cut a blind keyway. Wish I did ,like a slotter head for one of the BPs. My best guess it was a piece of 3/16th square cobalt lathe tool.
 








 
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