抄録
Quench cracking and distortion are generally considered to occur under united thermal and transformational stresses. In this paper quench residual stresses were examined by using a S 55 C steel bar. Various polyalkylene glycol (PAG) solutions and oil were prepared for the quench cooling solutions. The micro structure of the test piece was observed with a metallurgical microscope. The residual stresses caused by quenching were measured by Sachs' method. Considerable tensile and compressive stresses existed on the surface and in the center of the steel. The distribution of stresses and the hardness were related to the PAG content and could be explained clearly by the quench cooling rate.
