Thank you for your suport.
1º) We measure the hardness four times and take the average, and we usually measure at the centerline.
2º) We have done a metalographic study of two Almen strips. We have seen some surface decarburization whitin 15 and 30 um. I assume that it is created during the hot rolling, and I think it could also affect the intensity result. The hardness variability between core and surface is practicaly null.