Continuous casting mold and method for continuous casting of steel (as amended)

A continuous casting mold having a mold copper plate composed of copper or a copper alloy, the mold comprising:

• plural separate portions filled with a foreign metal of which thermal conductivity is 80% or less of thermal conductivity of the mold copper plate or 125% or more thereof,
• the plural separate portions being formed as circular concave grooves having a diameter of 2 mm to 20 mm or as quasi-circular concave grooves having a circle-equivalent diameter of 2 mm to 20 mm, the grooves being provided on an inner wall surface of the mold copper plate, and
• the plural separate portions being formed at least in a region from a meniscus to a position located 20 mm or more lower than the meniscus, the region being whole or part of the inner wall surface, wherein,
• a ratio of Vickers hardness HVc [kgf/mm2] of the mold copper plate to Vickers hardness HVm [kgf/mm2] of filled foreign metal satisfies relational expression (1) below:
• 0.3≦HVc/HVm≦2.3 (1), and
• the ratio of the thermal expansion coefficient αc [μm/(m×K)] of the mold copper plate to the thermal expansion coefficient αm [μm/(m×K)] of the filled foreign metal satisfies relational expression (2) below:
• 0.7≦αc/αm≦3.5 (2).