Title page for etd-0722116-144933


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URN etd-0722116-144933
Author Chien-Ting Liu
Author's Email Address No Public.
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Department Mechanical and Electro-Mechanical Engineering
Year 2015
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Effect of Double Track of Diode Laser on Tempering for AISI 4140
Date of Defense 2016-07-17
Page Count 63
Keyword
  • Back tempering
  • Double track
  • Laser heat treatment
  • Abstract Laser heat treatment changes microstructure of surface to improve hardness, wear resistance, fatigue strength when the bulk material retains high strength and toughness so that mechanical components extend its operating life which works in harsh conditions or being under heavy load and wear.
    As the laser beam has a limited spot dimension, when the workpiece requires a large area of hardening, multiple tracks have to be applied. In addition to ensuring the requirements of hardness and depth of hardened zone, the quality should be uniform. On the contrary, with a long time for operating, both uneven wear by non-uniform hardness distribution and different metallurgical structure will cause the dimensional error.
    Hardness decreased by back tempering is one of the most critical problems in laser heat treatment of large surfaces. In this paper, a diode laser with different process parameters was used to harden the surface of AISI 4140 by double track. The effect of hardness profile and microstructure of the hardened zone by back tempering was analyzed. And carefully controlling the process parameters to minimize the drawbacks of hardness decreased by tempering. The average hardness of two hardened zones was HV627, HV736, and the tempering area still reached HV505 by using 1100‚ĄÉcontrol temperature with a feed rate of 300 mm/min and a distance between the double track of 3mm.
    Advisory Committee
  • Jao-Hwa Kuang - chair
  • Bor-jeng Lin - co-chair
  • Hsin-Pao Chen - co-chair
  • Guan-Syong Huang - co-chair
  • Der-Min Tsay - advisor
  • Files
  • etd-0722116-144933.pdf
  • Indicate in-campus at 99 year and off-campus access at 99 year.
    Date of Submission 2016-08-23

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