# Steel delamination,have you ever seen it before?



## Ken from ontario

I found this topic  on a welding forum and although I had heard of it but never seen it until today:




They are supposedly called" lamellar tear" googled it and found this:
*Lamellar tearing is a material deficiency that can lead to brittle fracture in particular types of structural steel element assemblies.*
Some of you might know exactly what it is but as I mentioned I had only heard it could happen if different alloy  are used in combination of wrong heat treatment during its formation.
Just thought you  might find it interesting.


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## pdentrem

I will try to remember to take a couple pictures of a lump of steel at work tomorrow.
Pierre


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## dlane

Sounds like Chinese steel to me


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## 4GSR

Back in the late 1970's we had a problem with this same issue but in thicker sections of steel plate.  It was either 1" or 1-1/2" I don't remember which.  Turn out it came from Brazil!


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## pdentrem

Here is a couple pictures of a block of O1 about 2x1 1/2" x 1/2" thick. We use this and other scraps to hold the start of thin long strip going through our belt annealing furnace. Once the first 6-10 feet are in the furnace all is good but we need a little weight at the start. These blocks have gone through a few times, like 100s of times and they all end up looking like this.
Pierre


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## Ken from ontario

They must weigh a lot.  you probably couldn't sell them as anything but raw scrap steel.


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## Wreck™Wreck

Yes, have seen it in cold rolled sections in the past.

It has not been very common.


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## 12bolts

Laminar corrosion is seen very commonly in steel, (especially in salt water enviroments). I would think that there is some form of micro corrosion occurring on a molecular level to induce that effect.

Cheers Phil


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## stupoty

I had a thread ages ago about a piece of cold rold 1" square stock that had split in the middle, i had to grind the center out of it and weld fill it. 

Was very odd as when it happened it didnt make a noise it just kind of fell apart 

Stuart


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## RJSakowski

In forging, a cold shut can result in a tear.  A cold shut occurs when forge welding two pieces of steel together and an incomplete weld occurs.  In making Damascus or pattern welded steel, a steel/iron laminated bar is drawn out and cut in two or more pieces.  The pieces are stacked, heated to a welding heat, and welded together by hammering.  The wrong temperature, impurities, etc. can cause a poor weld to be made.  The laminate will stick together but applying and bending force can cause it to delaminate.

Rolled steel bar stock is made by rolling and rerolling steel billets until the desired shape and dimensions are attained.  a relatively locallized glitch will be drawn out into a planar defect which can cause this type of delamination failure.


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## eugene13

Certain types of steel will form a "pipe" as the ingot cools, if the ingot is rolled into a finished product the defect will appear as a lamination.  I don't know how common this problem is now days as most everything is continuous cast, but back in the day as much as the top third of an ingot would have be scrapped in order to get a good slab.


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## pdentrem

Even in con casting, one can get voids but not common. Sometimes the Nitrogen/Argon gas that we bubble into the crucible can be trapped as the metal is drawn through the die. When this happens we can see remains of the bubbles either on the surface as the metal cooled the nitro was pushed out or we get a void in the upper half of the cast metal. When this happens,  we just toss the bad parts back into the crucible.

When hand casting I see lots of pipe as the metal cools. At times I have a sprue that is as larger than the part so that liquid metal is drawn into the cooling part to prevent the formation of the void.
Pierre


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## juiceclone

I know that some steel is hot rolled and  "folded" and rolled etc. to arrive at what they want. I suspect that two different grades/hardness/duct-ability can be hot rolled together to give a softer backing to a very hard top layer.  That pix looks very much like that.  (In fact, it looks like armor)  If the steel is of a "random/unknown" source, it could be almost anything, and if it's from China .........???.


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## Fra_78

It was an issue in France in the 80's when steel started to be imported from eastern block countries. I remember a fishing boat made with Romanian steel peeling apart...


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## MetalMuncher

I saw something like this in the early 70s in a sheet metal shop where we made tool chests. Sometimes on the radius bends for a tool chest cover the steel would split open and de-laminate rather than forming a nice smooth surfaced radius. The sheet steel was being imported, but I am not sure from where.


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## Downunder Bob

I have seen it on chinese steel, also korean and Indian made steel, but chinese is generally the worst.


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## arvidj

Probably not relevant to the case at hand but ...

I have see 'delamination' on a set of brake rotors. I put a set of new rotors on my autocross car. I had the new set cryogenically treated before I put them on. Near the end of the season I started getting a serious shudder when I stepped on the brakes. Inspection showed that two of the rotors had 'chunks' of the surface missing. Think of having a plywood rotor and the outer layer of veneer had simply disappeared in parts of the rotor face. There were 'holes' that were about an 1/8 of an inch deep and several inches in length and width. The next 'layer' down was what looked like a reasonably smooth surface of good metal.

I attributed it to defects in the casting where it was not as 'all one piece of metal' and homogeneous as one would hope it to be, followed by the cryogenic treatment causing the layering to disconnect from one another, followed by extremely high heats finally breaking the layers apart and the chunks coming out of the rotor face.

Had not seen that happen before trying out the cryogenic treating and have not had another set treated or experienced the delaminiation since.


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## Dave Paine

Adding my own example from a few months ago.  I wanted a spacer and found a washer which just needed a small amount to be bored from the inner diameter.  I mounted in the chuck, started to bore with very light passes since the thin material could easily come loose in the chuck.

The washer did start to come loose.  When I stopped the lathe I found this seemed to be due to the steel delaminating.

I expected this would not turn with a good finish due to likely being hot rolled steel and a stamped washer, but I was not expecting the delamination.


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## Rustrp

Fra_78 said:


> It was an issue in France in the 80's when steel started to be imported from eastern block countries. I remember a fishing boat made with Romanian steel peeling apart...


Yes, but wouldn't that be getting two boats for the price of one. :|


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## Rustrp

dlane said:


> Sounds like Chinese steel to me


America makes it's own share of delaminated product, but most of it gets pulled in the testing/inspection cycle.


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## rock_breaker

Before I retired the cement plant maintenance supervisor (an excellent marksman/re-loader) had a lamination problem when he tried to open a hole in a cement slurry storage tank prior to repairs. The first of 4 shots went about 3/16 to 1/4 into the steel. the remaining shots enlarged the hole to about the size of a quarter but no deeper.  I felt a shaped charge would do the job but was unsure about the piping and pumps being able to withstand an instantaneous but brief overpressure. Never pushed the issue. Routine procedure was to either unbolt a big door (large enough for a 1.5 yd. loader) or work a drainage hole with oxy/act torch. either way led to the employees getting well soaked with slurry. Not sure why a 8 or 10 inch flange would not have worked.
Have a good day
Ray


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## jamby

Saw something very similar when in tech school years ago when one of the students made a pair of parallels and didn't anneal them after heat treat.   He had just ground them and they started to show crack lines with in minutes they all cracked apart.   Looking much like the wood splittering. 

Jim


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## Cactus Farmer

eugene13 said:


> Certain types of steel will form a "pipe" as the ingot cools, if the ingot is rolled into a finished product the defect will appear as a lamination.  I don't know how common this problem is now days as most everything is continuous cast, but back in the day as much as the top third of an ingot would have be scrapped in order to get a good slab.


We bought some big buck barrel quality steel from Washington state and the shipping was as much as the steel! We cut off 1.5" to avoid any issues with the sheared end and started drilling a barrel blank. There was a funny sound during the drilling. Reamed OK and then pulled the rifling button through it. It was cracked!!! One third of the barrel was junk and I sure would not trust the rest. We looked at the sawed end of the remaining bar and  there was a crack from the center out to the surface, Rejected the whole thing and contacted the seller. They were aware of the issue and refunded the whole amount including shipping. We made high dollar duck decoy weights with a lot of it and scraped the rest. We got lucky and recovered our $1000 investment.  It appears even good reputation sellers can get junk steel.


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## Downunder Bob

Cactus Farmer said:


> We bought some big buck barrel quality steel from Washington state and the shipping was as much as the steel! We cut off 1.5" to avoid any issues with the sheared end and started drilling a barrel blank. There was a funny sound during the drilling. Reamed OK and then pulled the rifling button through it. It was cracked!!! One third of the barrel was junk and I sure would not trust the rest. We looked at the sawed end of the remaining bar and  there was a crack from the center out to the surface, Rejected the whole thing and contacted the seller. They were aware of the issue and refunded the whole amount including shipping. We made high dollar duck decoy weights with a lot of it and scraped the rest. We got lucky and recovered our $1000 investment.  It appears even good reputation sellers can get junk steel.



In my experience it depends where the streel is made mare than the local supplier. I've only ever seen it in Chinese made steel, which unfortunately all the cut price merchants supply. I would bet that the steel inquestion was not made in USA, UK, Germany, Australia, and probably a couple of other countries to boot. Most likely from China, India, and quite a few others including Eastern European, South American and Asian, except Japan and probably south Korea.


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## Zathros

Same here with Some chineese suppliers. Somtimes even airbubbles in the Carbon steel they sell. But given the price they do and Some of those steel tools I use rarely then I buy from them. Otherwise as earlier mentioned from the high industry countries.


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## KBeitz

I had some steel out of Canada that came unlaminated. with more inspection I 
found layers of glass in the steel.


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## stupoty

KBeitz said:


> I had some steel out of Canada that came unlaminated. with more inspection I
> found layers of glass in the steel.



I wonder if that was some sort of flux residue?

Stuart


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## RWanke

During the 70s working at a shipyard they bought a bunch of foreign steel (Japanese, Chinese?) that would sometimes delaminate when bent or rolled but we would also find pockets of sand in it as it was being welded. Hit one and it would just blow a hole where you where welding.


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## Downunder Bob

We Have the same problem here in Australia. Big box hardware stores, sell poor quality steel. Flat or round bar and angle iron in particular are all rubbish. problems with welding, won't bend properly and also hard spots when cutting.

We are  a modern island nation of 25m people, yet we have stopped making things here. We used to build cars and trucks here, but no more. We also used to build ships, all gone, we used to build trains, trams ( trolley cars) washing machines fridges, TV's etc, now all gone everything is imported.

Over the last 40 year we have gone from the lowest unemployment in the modern industrialised world to one of the highest. The skills are being lost as people reach retirement age, no new ones being trained.


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## stupoty

RWanke said:


> pockets of sand in it as it was being welded. Hit one and it would just blow a hole where you where welding.



Always adds to the excitement of welding i guess


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