Investigators: Mark. R. Stoudt, Richard E. Ricker

Technical Description:

Large duplex stainless steel cylinders called "suction roll shells" are used in the processing of pulp to make paper. The service life of a typical suction roll shell is 5 to 8 years and it costs several hundred thousand dollars to replace one. Working with the only U.S. manufacturer of suction roll shells, Sandusky International, NIST is designing and conducting experiments which should lead to the development of a more fundamental understanding of the causes of these failures and metallurgical changes that could lead to an increase in the service life of these components.

Technical Objectives:

• Develop electrochemical measurement techniques and evaluate the electrochemical properties of the alloys used in the construction of suction roll shells in typical pulp and paper process environments and the influence of chemical composition and microstructure on corrosion.

• Develop experimental techniques for the measurement of corrosion fatigue crack propagation at low velocities in the pulp and paper process environment.

• Develop experimental techniques for studying corrosion fatigue crack initiation in pulp and paper process environments.

• Apply these experimental techniques to develop a fundamental understanding of the relationships between microstructure and performance of duplex stainless steels in the pulp and paper process environment.

Anticipated Outcome:

• Sandusky International will use the experimental methods, database and knowledge gained from their cooperation with NIST in this CRADA to develop suction roll shells with longer service life significantly reducing the cost of producing paper and strengthening their competitive position on the international market.

• Chemical species brought into the process environment from recycled paper may be contributing to reducing the service life of suction roll shells. As a result, development of alloys more resistant to this failure may result in promoting recycling of paper products.

• Reducing the cost of paper products and increased recycling will increase the use of paper products and influence many industries beyond the pulp and paper industry and their equipment manufacturers.

• The knowledge and the experimental techniques developed for this industry and environment can be used to help other industries where corrosion fatigue limits the service life of their components.

Accomplishments for FY 1995:

• Designed and began fabrication of a system for measuring corrosion fatigue crack propagation in a simulated pulp and paper process environment.

• Working with Sandusky International, designed a series of experiments for evaluation of the influence of microstructure on corrosion fatigue crack propagation.

• Conducted preliminary evaluation of the electrochemical behavior of the duplex stainless steel currently used for the construction of suction roll shells.

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Last modified: Mon Jan 06 09:46:15 1997 Metallurgy Webmeister