Patent ID: 7500847

Claim:
A die for forming a honeycomb structure, comprising: a die base having two surfaces, one of the two surfaces being provided with slits of a honeycomb shape, the other thereof being provided with back holes which communicate with the slits and introduce a forming material therethrough, the forming material introduced into the back holes being extruded from the slits to form the honeycomb structure, wherein the die base is obtained by stacking and bonding two plate-like members comprising a first member and a second member to obtain a die precursor, and providing the slits and the back holes in the die precursor, wherein the first member is the one surface of the die base and is made of a tungsten carbide-based super hard alloy containing at least tungsten carbide, wherein the second member is the other surface of the die base, is made of a metal material capable of causing at least one of three phase transformations of martensite transformation, bainite transformation, and pearlite transformation by cooling of an austenite phase, and whose phase has been transformed into at least one of three phase transformations of martensite transformation, bainite transformation, and pearlite transformation by cooling of an austenite phase after bonding of the first and second member, and wherein the die for forming a honeycomb structure is substantially free from breakage and is formed by mechanically processing the die precursor whose tensile and compressive stresses in a mutually bonded surface of the two plate-like members constituting the die precursor are 50 MPa or less.