抄録
In order to obtain the data on the execllent wear-resistance, I took the study of the sliding wear when the pearlite cast iron is isothermally heat-treated. In other words, the purpose of this study is to make a comparison between the various iron such as heat-treated cast iron, manufactured by General Motors, U.S.A., Meehanite cast iron, acicular cast iron, Ti-eutectic graphite cast iron, Ca-nodular graphite cast iron, engine cast iron of I.L.O. Germany, and the cast iron which was isothermally heat-treated in the structure of abrasion and the amount of wear.
Experiments were made on the lubricating abrasion and the paraffin-60 spindle oil was used as the lubricante under the constant conditions.
The results of the experiments are as follows:
1. The wear resistance of the cast iron isothermally heat-treated decreases remarkably and its mechanical properties are, generally speaking, better than as-cast.
2. The abrasion mechanism of the cast iron which was isothermally heat-treated is, unlike that of the as-cast, similar to the abrasion mechanism of steel, and is greatly relative to toughness and strength. In order to obtain the good results of the abrasion, it is absolutely important to have the cast iron of the great strength by fining the matrix.
3. According to the results gained by the various isothermal heat treatments, the cast iron is good when it is heat-treated at 850°C, and marquenched to 250°C-260°C and tempered to 260°C. Its hardness is about Rockwell “C” 46.
4. According to the isothermal heat treatments, the cast iron expands up to 0.16%-0.25% at the maximum, but this was due to the too big influence of the casting stress, therefore, it is necessaty to anneal the material at low temperature of around 500°C after as-casting, and to eliminate the casting stress.
