Patents by Inventor Rae W. Chang

Rae W. Chang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5507189
    Abstract: Apparatus and a method for evaluating the plane strain stretch formability for thin steel sheets used in automotive bodies to provide easy evaluation of the plane strain stretch formability. The apparatus includes: a lower die and an upper die with a lock bead installed thereon. A rectangularly shaped test specimen is inserted between the upper and lower dies and, and is clamped by means of the lock bead along the circumferential edge of the test specimen, so that the material of the test specimen can be moved into the upper die. A punch is elevated to apply a stretch forming force on the test specimen, and then, the plane strain stretch formability is evaluated based on the fracture limit punch height at the instant of the fracture. The punch has a saddle-like, semi-cylindrical shape.
    Type: Grant
    Filed: August 25, 1994
    Date of Patent: April 16, 1996
    Assignees: Pohang Iron & Steel Co., Ltd., Research Institute of Industrial Science & Technology
    Inventors: Young S. Kim, Jeong C. Kim, Won J. Choi, Rae W. Chang, Ki S. Kim, Moon H. Yu
  • Patent number: 5431753
    Abstract: An austenitic high manganese steel having superior formability, strengths and weldability, and a process for manufacturing the steel, are disclosed. The superior formability of the steel is suitable for use on automobiles and electronic panel. The steel has a composition of (in weight %) less than 1.5% of C, 15.0-35.0% of Mn, 0.1-6.0% of Al, and the balance of Fe and other indispensable impurities. The size of the austenite grains is less than 40.0 .mu.m, and, one or more elements are added by selecting them from a group consisting of less than 0.60% of Si, less than 5.0% of Cu, less than 1.0% of Nb, less than 0.5% of V, less than 0.5% of Ti, less than 9.0% of Cr, less than 4.0% of Ni, and less than 0.2% of N, thereby providing an austenitic high manganese steel having superior formability, strengths and weldability.
    Type: Grant
    Filed: August 26, 1993
    Date of Patent: July 11, 1995
    Assignees: Pohang Iron & Steel Co. Ltd., Research Institute of Industrial Science & Techology
    Inventors: Tai W. Kim, Jae K. Han, Rae W. Chang, Young G. Kim