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 that the part being needed in view of its usage/function, thereby improving strength. 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. To solve the above problem, the surface treatment method of the present invention can perform the local heating and the surface treatment processes as continuous processes by the same equipment by merging and combining a local heating technology and an ultrasonic nanocrystal surface modification (UNSM) technology, thereby improving all mechanical characteristics of an object, performance thereof, and a lifespan thereof.