Quenching<br/>is the heat treatment by which austenite transforms to ____. A: bainite B: pearlite C: martensite D: ferrite

During heat treatment of steel, austenite transforms into martensite by A: annealing B: austenitizing C: quenching D: normalizing

In the as-quenched state, martensite is very hard and so brittle that a heat treatment known as_________must be accomplished sequently. A: normalizing B: annealing C: tempering D: austempering

英译汉： Carbon steel(碳钢) Martensite(马氏体) Pearlite(珠光体) Cementite(渗碳体) Ferrite(铁素体) Austenite(奥氏体) annealing(退火), normalizing(正火), quenching(淬火), and tempering(回火)