Dissertation > Excellent graduate degree dissertation topics show

Study on Coated Electrodes in Resistance Spot Welding of Galvanized Steel Sheet

Author: ShenQiao
Tutor: ZouJiaSheng
School: Jiangsu University of Science and Technology
Course: Materials Processing Engineering
Keywords: Galvanized steel sheet Resistance spot welding Coated electrodes EDM deposition Deposition process Interface structure Electrode life Failure mechanism
CLC: TG453.9
Type: Master's thesis
Year: 2010
Downloads: 90
Quote: 1
Read: Download Dissertation

Abstract


In this paper, the electric spark deposition technology in Ni / cermet coating deposited on chromium zirconium copper electrode . Orthogonal experimental method to study the impact of the deposition process deposition efficiency and coating quality , and to optimize the process parameters ; resistance spot welding galvanized steel coated electrode prepared using the optimization process , based on the shear strength of resistance spot welding joints standard assessment coated electrode and uncoated electrode life ; coated electrode coated electrodes before welding , 300 solder joints and failure morphology analysis using scanning electron microscopy , energy dispersive spectroscopy and hardness testing means , structure and composition , and on this basis to explore the failure mechanisms of galvanized steel sheet spot welding electrodes , and further measures to improve the life of the coated electrode . The deposition current deposition voltage electrode speed , bar speed is the main process parameters affect the surface of the electrode spark deposition multilayer coating , in which the influence of the deposition voltage ; nickel coating deposition process parameters : the the deposition current value of 20A , deposition voltage value of 7.5V , the electrode speed in 40r/min-60r/min between , bars speed 3000r/min; deposition of metal ceramic layer deposition process parameters : the deposition of the current value of 20A , the deposition voltage value of 7.5V, the the electrode speed in 20r/min between bars speed 3500r/min. Maximum hardness value of the coated electrode 778HV, much higher than the hardness of the chromium zirconium copper substrate ; coated electrode end surface and cross section morphology and composition analysis showed that : The better the quality of the coating , the coating surface to see any form of crack , porosity, inclusions and other defects exist, the coating structure for the cermet layer / nickel cermet layer / nickel layer / nickel- chromium zirconium copper layer / chromium zirconium copper matrix . The test results show that : at least 800 times the life of the uncoated electrode coated electrode life is at least 2000 times , compared to non- coated electrode , the service life of the coated electrode is about 2.5 times . Analysis that coating electrodes to improve the lifetime of galvanized steel resistance spot main mechanism coating improves the resistance to plastic deformation of the electrode capabilities and limitations of the metallurgical reaction between zinc and an electrode . Improve the resistance spot welding electrode matrix strength and resistance to plastic deformation capacity, improving the coating composition, structure designed to enhance the bonding strength of the coating and the substrate and coating properties, and can further improve the life of the spot welding electrodes .

Related Dissertations

  1. Research on Operational Life Span and Applications of Coated Electrode Resistance Welding for Galvanized Steel,TG453.9
  2. Pull off pieces of structural damage to buried nonlinear analysis numerical simulation,V222
  3. Deformation Mechanism and Construction Information Management of Highway Cutting Slope in Strongly Weathered-areas,U416.14
  4. The Research on Physical Model Experiment of the Load-Unload Response Ratio Pattern and Its Failure Mechanism of Debris Landslide Induced by Rainfall,P642.22
  5. Containing artificial defects C_f / Al composites Compression Failure Behavior,TG115.53
  6. Reasearch on Welding Process and Mechanism of 9Ni Steel for Large LNG Storage Tank,TG457.11
  7. A Study on Failure Mechanism and Stability of High and Steep Rock Slope in the Open Pit of Daye Iron Mine,TD854.6
  8. Research on the Interface Structure and the Infiltration-mechanism of SiC_p/AZ91D by Vacuum,TB331
  9. Experimentation Study of Low-cycle Plastic Double Failure Mechanism of Steel Bar under Axial Load,TU391
  10. Or Hom -bottom flow plunge pool flow structure of the stilling basin boundary role overcurrent research,TV135
  11. Investigate on Phosphating of Galvanized Steel,TG174.4
  12. Study on Failure Mechanism and Treatment of Shaft Influenced by Rock Collapsing in Goaf Area,TD325.4
  13. Experimental and Numerical Study on Seepage Mechanism of Rock Failure,TD313
  14. Investgation of Fabrication of Aramid Fiber Flexible Composite and Its Stab Resistance,TB332
  15. Life Assessment and Fault Diagnosis of Boiler Tubes in Power Plant,TM621.2
  16. Study of Resistance Spot Welding Microstructure and Properties of Al-Mg-Si-Cu Based Auto Body Sheets,U465
  17. Researching on Distortion Failure Mechanism and Rational Distribution of Controlling Measures for Consequent Bedding Rock Slope with Steep Dip-Angle,U416.14
  18. Investigation of Failure Mechanisms of Orthotropic Steel Bridge Decks under Terror Blast Loading,U441
  19. Study on Intermittent Turning of Shell Ring Material 2.25Cr-1Mo-0.25V Steel and Tool Failure Mechanisms,TG51
  20. 5.12 Wenchuan earthquake typical cut slope failure mechanism of gravity retaining wall,U417.11
  21. The Failure Mechanism, Safety Evaluation and Seismic Protection Technique of Girder Bridge in the Strong Earthquake Area,U442.55

CLC: > Industrial Technology > Metallurgy and Metal Craft > Welding, metal cutting and metal bonding > Welding process > Pressure welding > Other pressure welding
© 2012 www.DissertationTopic.Net  Mobile