フェライト球状黒鉛鋳鉄の低エネルギー打撃による衝撃試験

概要

論文の詳細を見る
Fracture process of ferritic spheroidal graphite cast iron in Charpy impact test was investigated by means of low energy blow on the specimen followed by fracturing it at 77 K and measuring the crack length propagated by the blow. Bending load-time curves obtained by an instrumented testing machine were converted to load-deflection curves by law of conservation of energy. Crack initiation energy, the energy absorbed up to the maximum bending load, is supposed to be the energy required for the notch root to attain both the fracture strength and fracture strain, but the estimated energy is fairly lower than the experimentally obtained. During crack propagation, the stress intensity factor remained almost unchanged, and the crack extension energy is proportional to the width of the ligament. The observed compliances of spring back after crack propagation are bigger than those expected from the crack opening displacement, a reason of which may be lowered Young's modulus in distorted ligament section.
Japan Foundry Engineering Societyの論文