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.

 

[pdentrem]

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

 

[dlane]

Sounds like Chinese steel to me

 

[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!

 

[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

 

[Ken from ontario]

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

 

[Wreck™Wreck]

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

It has not been very common.

 

[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

 

[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

 

[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.