Patent ID: 7434432

Claim:
A die apparatus for high temperature forming of a metal product of a selected shape, the apparatus comprising: at least two opposing die segments having inner surfaces together forming a hollow mold chamber for receiving a mold blank between the die segments, the inner surface of at least a first one of the die segments having a forming surface which forms at least part of the selected metal product shape, the die segments being of a first material having a first coefficient of thermal expansion CTE 1 ; and at least one insert of a second material mounted on the forming surface of the first die segment so as to project into the mold chamber and form an indent of predetermined shape in the mold blank formed against the forming surface, the second material having a second coefficient of thermal expansion CTE 2 higher than CTE 1 and higher than the coefficient of thermal expansion CTE 3 of the metal product to be formed in the cavity, whereby the relationship between the coefficients of thermal expansion of the die segment, metal product to be formed, and insert is as follows: CTE 1 <CTE 3 <CTE 2 ; whereby the insert shrinks to a shape of dimensions less than the formed shape of the indent in shaped metal part after forming and cooling in the mold chamber so that the shaped metal part is released from the insert.