Different material properties from a similar mild steel billet

[kaninchenofmersey]

Hi
Recently I tested 3 samples with the same dimension and shape namely T1, T2 and T3.
All was cut from the same mild steel billet. T1 was cut vertically across the billet whilst T3 and T4 were cut in horizontal direction.

T1 underwent strain gauge measuremnt before it was tensile tested on INSTRON machine.

T3 and T4 didnt went strain gauge measurement and were tensile tested on the same machine.

The results
Young modulus (YM) for T1= 205.7 GPa
YM for T3 = 208 Gpa
YM for T4 = 312 Gpa

Why there is such discrepancies between the samples?

Thanks in advance

 

[CoryPad]

How was strain measured on each specimen?

Regards,

Cory

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[kaninchenofmersey]

InSTRON machine has its own data processing.
I suspect the different setup on the machine might affect the result but I couldnt verify it as I am not familiar with the machine.

 

[ApplicationSupporter]

As CoryPad asked - how are you measuring strain on the specimen (strain gauges, or extensometer?) Your original post is not clear. I think that data processing is not the key to your problems.

 

[arunmrao]

Any physical inconsistencies in the ingot. Just this evening I was discussing the various defects observed in steel ingots. Is this sample from a continuously cast strand or from conventional ingot molds.

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[EdStainless]

You need to look at microstructure. If this is from the as cast billet then there could be huge variation in grain size and orientation.
Any heat treatment? That also could be a factor.
You need to find out what strain range the software is using for modulus calculation. It may be taking data out of the linear region.

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