The proper preliminary heat treatment for T12 steel is . A: complete annealing B: homogenizing annealing C: spheroidizing annealing D: isothermal annealing

____is<br/>a low-temperature heat treatment used to eliminate all or part of the<br/>effect of cold working in steels. A: Normalizing B: Spheroidizing C: Annealing D: Process<br/>annealing

For tool steel, the heat treatment is usually: () A: spheroidizing followed by quenching and low temperature tempering B: carburizing followed by quenching and low temperature tempering C: Quenching and high temperature tempering D: normalizing