Brass & steel long knife.?

I bought a knife from a local blacksmith. The full tang were the handle is & 2/3rd of the back of the blade is of some form of what appears to be a spring brass. About 1/8th inch thick. The bottom 1/3rd of the blade in front of the handle to the point is of some form of very hard steel. The two metals have been blacksmith forged together. Do you think this will hold together. The blade part is so hard about all you can do is polish the edge with a hard file. I did manage to get it sharp enough to shave with after filling on the blade for over a hour. & it had a edge on it not the best edge when I started. So will the two metals as such hold bound together in a blacksmith weld?