Hot die steel, used for large solid dies in drop forging, should necessarily have

Cold shut (lap) may occur in products obtained by:

A small bore is designated as $$25H7.$$ The lower (minimum) and upper (maximum) limits of the bore are $$25.000mm$$ and $$25.021$$ respectively. When the bore is designated as $$25H8,$$ then the upper limit is $$25.033mm.$$ When the bore is designated as $$25H6,$$ then the upper limit of the bore in $$mm$$ is