The small punch (SP) test technique can generate tensile, toughness, and creep strength data from very small specimens, enabling nondestructive sampling from large components. This has accelerated industry interest in SP, particularly in the energy sector. A round-robin for the SP creep test was organized within the EPERC network on a 1CrMoV rotor steel, primarily to contribute to harmonizing the test procedure for this emerging method. This presentation analyzes the SP creep test results performed at several temperatures and one load level to assess their inter-comparability and interpret the results concerning conventional uniaxial creep tests. The SP loading geometry appeared to be a key parameter in evaluating the SP results, particularly for correlation with uniaxial creep behavior. A standardization initiative for the SP test method, including creep as well as low-temperature testing for determining tensile and toughness properties of metallic materials, has recently started via a CEN Workshop.

Creep-fatigue crack formation (endurance) and crack growth rate data are necessary inputs for assessing the structural integrity and for estimating the design life of high temperature components in power generation and aircraft engine industries. Ensuring consistency in the reported test data, as well as an understanding of the inherent scatter and its source in the data, are both necessary for assuring quality and limitations of the analyses that rely on the data. In 2008, the American Society for Testing and Materials (ASTM) under the umbrella of its subcommittees E08.05 on Cyclic Deformation and Crack Formation and E08.06 on Crack Growth, and the sponsorship of Electric Power Research Institute (EPRI) through its international experts’ working group on creep-fatigue embarked on the task of developing separate standard test methods for creep-fatigue crack formation and creep-fatigue crack growth. The first standard entitled, “E-2714-09: Standard Test Method for Creep-fatigue Testing” was developed in 2009 and was followed up with a round-robin consisting of 13 laboratories around the world for testing the newly developed standard. This paper discusses the results of this round-robin concluded in 2012 using the widely used P91 steel that led to the formulation of the Precision and Bias statement contained in the version of the ASTM standard E2714 that was successfully balloted in the year 2013.

Solid particle erosion (SPE) harms steam and gas turbines, reducing efficiency and raising costs. The push for ultra-supercritical turbines reignited interest in SPE’s impact on high-temperature alloys. While the gas turbine industry researches methods to improve erosion resistance, a similar need exists for steam turbines. Existing room-temperature SPE test standards are insufficient for evaluating turbine materials. To address this gap, an EPRI program is developing an elevated-temperature SPE standard. This collaborative effort, involving researchers from multiple countries, has yielded a draft standard submitted to ASTM for approval. This presentation will detail the program, test conditions, and the draft standard’s development.

Work has been progressing over recent years to develop a standard test method for high temperature solid particle erosion testing. Early in 2015 this standard was published by ASTM as G211-14 Standard Test Method for Conducting Elevated Temperature Erosion Tests by Solid Particle Impingement Using Gas Jets. To support the development of this standard the European funded METROSION project has been conducting a comparison of different apparatus which employ different nozzle geometries, acceleration lengths, stand-off distances and heating and accelerating processes. The aim is to understand the influence these instrumental and experimental parameters have on the measured erosion rate and erosion mechanism. As part of this work three very distinct approaches have been compared using a common erodent and test pieces. Measurements have been performed at 600 °C with particle velocities of 50 to 320 m/s, using different stand-off distances, acceleration lengths and nozzle diameters for impact angles of 30 and 90°. This is the first time a comprehensive comparison of these parameters has been conducted and shows the relative influence of these experimental variables.

High-temperature solid particle erosion (SPE) is a major threat to efficiency in power plants and jet engines, potentially reducing turbine efficiency by 7-10% and causing significant CO 2 emissions. The sources of these particles vary widely, from volcanic ash in engines to fly ash in boilers and scale in turbines. While better surface engineering and coatings offer solutions, their development is hampered by a lack of standardized test methods and reliable models. To address this, the METROSION initiative aims to establish a comprehensive framework for characterizing the high-temperature SPE performance of new materials and coatings. This framework will require a step change in test methods and control, focusing on accurately measuring key parameters like temperature, flow rate, particle properties, and impact angles. This paper outlines the initiative’s goals, with a particular focus on the techniques used for in-situ measurements of temperature, particle velocity, and 3D shape/size.

Because of the problems experienced with steam-side oxidation in commercial power plants, there has been continuing interest in better understanding the steam oxidation behavior of creep strength enhanced ferritic steels such as grades 23, 24 and 91 as well as 300-series stainless steels such as 347H and 304H. Analysis of field-exposed tubes has provided information on the oxidation reaction products but relatively few specimens are available and there is limited information about the kinetics. Specimens have included tube sections with a shot peened surface, a treatment that is now widely used for austenitic boiler tubes. To complement this information, additional laboratory studies have been conducted in 1bar steam at 600°-650°C on coupons cut from conventional and shot-peened tubing. Exposures of 1-15 kh provide some information on the steam oxidation kinetics for the various alloys classes. While shot-peened type 304H retained its beneficial effect on oxidation resistance past 10,000 h at 600° and 625°C, the benefit appeared to decline after similar exposures at 650°C.