A problem with the interpolation function

Hello everybody,

I'm a new user of Comsol but I have to simulate the behavior of a material using this software.
I have numerical values obtained by experience in an excel file. I made a .txt file with this values (first column the argument and the second the values of y axis). I put 1 in the number of arguments and attached my .txt file, but when I click on 'plot', I get a curve that obviously doesn't match my table of values. I find values on the graph that my x-variable (the argument of my discrete function) doesn't reach. Moreover, the person who did the experimentation plotted the curve somehow, and the shape of this curve is nothing like what i get on Comsol.

I still have another question. I'm supposed to use the steel B500S in the simulation. This reference is given by the European norm UNE 36-068-94, but I notice that Comsol uses the UNS norm, which I never heard of, may be it's the norm used by the USA or something like that. Anyway, I don't know how to recognise my material in this norm.

Thanks for reading me if you get here,
Imane.