SURFACE TREATMENT METHOD USING LOCAL HEATING AND ULTRASONIC NANOCRYSTAL SURFACE MODIFICATION

摘要

The present invention relates to a surface treatment method for performing heat treatment only with regard to a part of a large component, such as a crankshaft of a large diesel engine, a large gear, a bearing, a mold, or the like, the part being needed in view of the usage/function thereof, thereby improving the strength thereof. Conventional surface treatment methods using existing heat treatment and local heating technologies have a problem in connection with the limitation in that no consideration has been made regarding methods for endowing better mechanical characteristics by modifying the surface of the object together with hardness improvement and post-treatment for changing tensile residual stress formed in the surface of the object after heat treatment to compressive residual stress. In order to solve said problem, the present invention provides a surface treatment method using local heating and ultrasonic nanocrystal surface modification, the method being configured such that local heating and surface treatment processes can be performed as continuous processes by the same equipment by merging/combining a local heating technology and an ultrasonic nanocrystal surface modification (UNSM) technology, thereby improving all of the mechanical characteristics of the object, the performance thereof, and the life thereof.