JPS6473048A - Sliding friction member - Google Patents

Abstract

PURPOSE:To maintain the sliding friction in the initial stage of use at a level equal to that after use with the lapse of time, by forming the inner part of a sliding friction member made of cast iron-type metal into pearlitic structure and also forming the surface-layer part of the above member into ferritic structure. CONSTITUTION:A sliding friction member performing its function by being brought into frictional contact with a semimetallic sliding friction member is manufactured by using cast-iron-type metal. At this time, the above member is formed into the prescribed shape by using a cast iron-type metal having pearlitic structure, which is heated up to about 900 deg.C for about 1hr in a decarburizing atmosphere. After this heat treatment, the above member is cooled, e.g., in a nitrogen atmosphere of ordinary temp. By this method, the above member is provided with a structure in which the inner part alone remains in the state of pearlitic structure and the surface layer part has a soft ferritic structure of about 8mum grain size. In the resulting sliding friction member mentioned above, the soft surface-layer part is subjected to frictional sliding at a high coefficient of friction by sure adhesion in the initial stage of use, and, after use with the lapse of time, sufficient sliding friction can be carried out in the part of pearlitic structure appearing at the surface due to the wear of the above surface- layer part, by means of the frictional surface become used.