Method and apparatus of evaluating mechanical properties of steel

A method of evaluating mechanical properties of steel which comprises the steps of:

• measuring tensile strength, yield point, elongation, hardness, grain size and chemical composition of first steel samples to be evaluated;
• determining, on the basis of the measurements thus obtained, an empirical equation for each of the tensile strength, yield point and elongation of the first steel samples in which the hardness, grain size and chemical composition thereof are contained as variables;
• measuring hardness, grain size and chemical composition of a second steel sample to be evaluated;
• and
• deriving the tensile strength, yield point and elongation of the second steel sample to be evaluated by substituting the hardness, grain size and chemical composition measured for the second steel sample in each empirical equation.

A method of evaluating mechanical properties of steel which comprises the steps of:

• measuring shelf energy, transition temperature, temperature range of an energy transition region, hardness, grain size and chemical composition of first steel samples;
• determining, on the basis of the measurements thus obtained, an empirical equation for each of shelf energy, transition temperature, and temperature range of an energy transition region of the first steel samples in which the hardness, grain size and chemical composition thereof are contained as variables;
• measuring the hardness, grain size and chemical composition of a second steel sample to be evaluated;
• deriving shelf energy, transition temperature, and temperature range of an energy transition region of the second steel sample to be evaluated by substituting the hardness, grain size and chemical composition measured for the second steel sample in each empirical equation;
• and
• determining energy absorbed at a given temperature from an energy transition curve approximated on the basis of the shelf energy, transition temperature, and temperature range of the energy transition region of the second steel sample to be evaluated using an equation ##EQU12## where vET:
• energy absorbed at temperature T
• vEs:
• shelf energy
• vTrE:
• transition temperature
• T.sub.2 -T.sub.1 :
• temperature range of the energy transition range.

A method of evaluating mechanical properties of steel which comprises the steps of:

• measuring tensile strength, yield point, elongation, shelf energy, transition temperature, temperature range of an energy transition region, hardness, grain size and chemical composition of first steel samples to be evaluated;
• determining, on the basis of the measurements thus obtained, an empirical equation for each of the tensile strength, yield point, elongation, shelf energy, transition temperature, and temperature range of the energy transition region of the first steel samples in which the hardness, grain size and chemical composition thereof are contained as variables;
• measuring hardness, grain size and chemical composition of a second steel sample to be evaluated;
• deriving the tensile strength, yield point, elongation, shelf energy, transition temperature, and temperature range of the energy transition region of the second steel sample to be evaluated by substituting the hardness, grain size and chemical composition measured for the second steel sample in said empirical equations;
• and
• determining the energy absorbed at a given temperature from the shelf energy, transition temperature, and temperature range of the energy transition region of the second steel sample to be evaluated.