Loading...

Corrosion Behavior of TLP Bonded 304 Stainless Steel Using Cobalt Base Interlayer

Sadooghi, Sajjad | 2022

140 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55428 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Ekrami, Ali Akbar; Tavakoli, Rouhollah
  7. Abstract:
  8. The transient liquid phase bonding is a combination of penetration bonding and hard soldering processes. This method is based on the diffusion in the solid state of the melting point reducing elements from the joint zone into the base metal and isothermal solidification that the kinetics of this reaction are controlled by diffusion in the solid state. In this study, we investigate the bonding of 304 stainless steel with cobalt base interlayer by transient liquid phase method and studies of microstructural and corrosion resistance of the joint. Three different temperatures are considered for the bonding and after each bonding, the microstructure is examined with a optical and scanning electron microscope. It was found that 1210 °C and 90 minutes holding time are suitable for complete removal of the eutectic areas from the joint center. The homogenization operation was performed on completely isothermal solidification samples at 1000 °C for 1h and 2h, which showed that the shear strength of the bond was reduced. The maximum strength is obtained from the joint is 96% of base metal which has been heat treated at 1210 °C and 90 minutes holding time. Then we study the corrosion properties of samples in two solutions, one of them is sulfuric acid with 10% concentration and other sodium chloride with 3.5% concentration. Corrosion results in both solutions show that the bonding reduces corrosion properties and bonding with eutectic and intermetallic compounds have the lowest corrosion resistance, its corrosion rate in seawater environment in mpy is 0.938 and in the acidic environment equal to 118.74, and the homogenized specimen has better corrosion resistance than the other bonding specimens and its corrosion rate is in sea water and acidic environments respectively 0.079 and 31.54 in mpy. Finally, the corrosion resistance of bonding is investigated in high temperature operations, and the results show the TLP bonding reduce corrosion resistance at high temperatures.

  9. Keywords:
  10. Transient Liquid Phase (TLP) ; Polarization ; 304 Austenitic Stainless Steel ; Nickel Based Interlayer ; High Temperature Oxidation ; Cobalt Based Interlayer

 Digital Object List

 Bookmark

No TOC