High-temperature erosion testing standard and round robin testing

Abstract

Solid Particle Erosion (SPE) of hardware remains an ongoing concern with the operation of Steam Turbine power plants. SPE of both rotating and stationary components of turbines leads to loss of efficiency, higher cost of operation and maintenance of turbines. Ultra Supercritical (USC) and advanced USC programs underway in North America, Europe and Asia have created renewed interest in the understanding of the effects of SPE on the advanced alloys and high-temperature SPE testing. ASTM's G76 "Standard Test Method for Conducting Erosion Tests by Solid Particle Impingement Using Gas Jets" defines a standard test method for conducting room temperature SPE erosion testing. The current G76 erosion test reference conditions are 90 degree particle impingement with 50 micron alumina on AISI 1020 steel at room temperature and a relatively low particle velocity of 30 m/s. The objective of the current Electric Power Research Institute (EPR) sponsored program is to develop an elevated temperature SPE standard that will provide more appropriate reference conditions for SPE conditions encountered in current and next generation steam turbine applications. Currently such test standard is not available from any of the standards organizations. Various laboratories around the world have developed their own equipments and procedures to conduct there tests. This makes it difficult to compare these interlaboratory test results for the purpose of screening and selecting alloys and coatings for erosion mitigation. Organizations from the United States, United Kingdom, Canada, China, Germany, Italy and India have so far expressed interest in participating in an interlaboratory "Round Robin" test program to develop an elevated temperature erosion test standard. Initial test conditions and test matrix have been developed for this round robin test program. Type 410 stainless steel substrate will be used at impingement angles of 30 and90 degrees with 50 micron alumina erodent with particle velocity of 200 m/s (667 f7s) at room temperature and 600 C (1112 F). This paper will provide an overview of prior elevated temperature SPE testing, test capabilities of participating organizations and the status of the development of the new test standard. Copyright © 2011 Electric Power Research Institute Distributed by ASM International®. All rights reserved.