METHOD FOR ESTIMATING BREAKING TOUGHNESS OF CARBIDE ALLOY

PROBLEM TO BE SOLVED: To easily and accurately provide a method for estimating a breaking toughness value of carbide alloy without breaking the carbide alloy. SOLUTION: In the method for estimating the breaking toughness value of carbide alloy with a connection metal with WC as a main constituent and Co or Co and Ni as main constituents, the coercive force and a breaking toughness value KIC of the carbide alloy where the composition ratio of Co and Ni is known are measured in advance and the relationship between the coercive force and the breaking toughness value IIC is obtained. Then, the coercive force of the carbide alloy to be measured is measured and the breaking toughness KIC is estimated from the coercive force of the above carbide alloy to be measured by the above relationship where the contents of Co and Ni are equal.