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Improvement and Modeling of the Cast Pin Tear Test

A modification of the original Cast Pin Tear Test (CPTT) developed by Hull in the 1970’s has been ongoing at the Welding and Joining Metallurgy Lab of OSU for several years. Its primary use is to quantify weld solidification cracking in Ni-base alloys. Recent with the modified CPTT have shown that it is sensitive to the effect on small compositional variations on the solidification cracking behavior in high-chromium, Ni-base filler metals, such as those used in the Nuclear Industry. Its ranking of solidification cracking susceptibility has been shown to be comparable to other weldability tests, such as the Transvarestraint test.

The CPTT apparatus has been subjected to further improvement to provide better reliability in testing of difficult to cast alloys. Induction levitation melting in combination with infrared temperature measurement is usd to promote controllable, repeatable, and uniform heating of the molten test button.

A finite element analysis (FEA) model of the testing process with the improved CPTT apparatus has been developed using the ProCastTM software. Using FEA simulations, the CPTT mold material and design have been optimized to reproduce a typical range of weld thermal histories in the cast pin. Current FEA simulations are aiming to quantify the critical strain that causes solidification cracking in the cast pin. This critical strain can be used as a material related criterion for ranking the solidification cracking susceptibility in metallic alloys.

An extensive validation study has been conducted, which aimed to evaluate the reproducibility of the improved CPTT. The results were used to generate a ranking database for the solidification cracking susceptibility in various high chromium Ni-base filler metals and in dilutions of such filler metals with Type 304 stainless steel.


Industry Sponsor: Electric Power Research Institute

Faculty: Boian Alexandrov (OSU)

Graduate students: Timothy Luskin (MS), Eric Przybylowicz

Industry Contact: Steven McCracken


Thesis: Timothy C. Luskin, Modeling and Optimization of the Cast Pin Tear Test

Publications

  1. Luskin T.C., B.T. Alexandrov, J.C. Lippold, S.S McCracken, A New Generation Cast Pin Tear Test, Welding in the World, submitted for publication, November 2013.
  2. Luskin T.C., B.T. Alexandrov, J.C. Lippold, S.S McCracken, Preliminary Finite Element Analysis and Optimization of the Cast Pin Tear Test, 10th International Seminar Numerical Analysis of Weldability, Technische Universität Graz, accepted for publication, 2012.
  3. T.C. Luskin, B.T. Alexandrov, J.C. Lippold, and S.L. McCracken. 2012. Development and validation of a new generation cast pin tear test, 10th Int. EPRI Conf. on Welding and Repair Technology for Power Plants, Marco Island, FL, June 2012.
  4. Alexandrov B.T., A.T. Hope, B.J. Sutton, B.B. Alexandrov, and J.C. Lippold, Improvement and Modeling of Solidification Process in the Cast Pin Tear Test, Welding and Fabrication Technology for New Power Plants, Second International EPRI Conference, 2011.