Hard-surfaced cast iron articles and method and apparatus for manufacturing the same

A method for manufacturing hard-surfaced cast iron rolls, comprising the steps of;

• casting the roll and cooling the same in a manner such that, upon completion of said cooling, the crystal structure of the roll is that of grey cast iron;
• machining the roll substantially to its final dimension;
• mounting the roll for rotation about an axis of rotation;
• remelting the roll surface to be treated by directing at least one electron beam onto a zone of the roll surface to be treated and rotatably displacing the roll in a continuous manner and axially displacing the electron beam relative to the roll to direct the at least one electron beam onto different remelting zones;
• cooling the treated roll surface;
• and
• machining the roll to its final dimensions and surface smoothness subsequent to said remelting and cooling steps.

A roll manufactured by a method comprising the steps of:

• casting the roll and cooling the same in a manner such that, upon completion of said cooling, the crystal structure of the roll is that of grey cast iron;
• machining the roll substantially to its final dimension;
• mounting the roll for rotation about an axis of rotation;
• remelting the roll surface to be treated by directing at least one electron beam onto zones of the roll surface to be treated and rotatably displacing the roll and axially displacing the electron beam relative to each other to direct the at least one electron beam onto different remelting zones in a punctiform manner;
• cooling the treated roll surface to define a punctiform pattern of treated hardened zones and untreated zones of lower hardness;
• and
• machining the roll to its final dimensions and surface smoothness subsequent to said remelting and cooling steps;
• and
• wherein the final surface harness of the treated surface of the roll is in the range of about 500 to 900 HB and wherein the treated roll surface is defined by a pattern of treated hardened zones between which are substantially untreated zones of lower hardness.