Evaluation of Creep Strength of Heterogeneous Welded Joint in HR6W Alloy and Sanicro 25 Steel

Abstract

This article presents the results of investigations on HR6W alloy and Sanicro 25 steel and the dissimilar welded joint made of them. The characteristic images of microstructure of the investigated materials in the as-received condition and following the creep test, observed with a scanning electron microscope (SEM), are shown. The X-ray analysis of phase composition of the existing precipitates was carried out. The method for evaluation of creep strength based on abridged creep tests carried out at a temperature higher than the design one is presented. The obtained results do not deviate from the values of creep strength determined in longterm creep tests. The maximum difference in creep strength of the investigated materials is ±20%, which is in compliance with the acceptable scatter band. The methodology presented can be used for verification of creep strength (life time) of the material of finished components to be operated under creep conditions.

Design and Experimental Study of HTSG for Waste to Energy: Analysis of Pressure Difference

“…In this study, a laboratory scale experiment was conducted beforehand, and the HTSG material was SUS310. The thermal conductivity of SUS310 is similar to that of HR6W [9] at temperatures below 400 °C, as shown Furthermore, the overall heat transfer coefficient was computed using Equation (2).…”

“…In this study, a laboratory scale experiment was conducted beforehand, and the HTSG material was SUS310. The thermal conductivity of SUS310 is similar to that of HR6W [9] at temperatures below 400 • C, as shown in Figure 3, however, its conductivity differs from that of HR6W at temperatures above 400 • C. Further analysis on this discrepancy would be necessary prior to actual site applications. in Figure 3, however, its conductivity differs from that of HR6W at temperatures above 400 °C.…”

“…Extensive research on materials has been recently conducted to overcome this challenge. Zieliński et al [9] introduced a material with an austenitic structure (HR6W, Sanicro 25) that has stability up to 750 • C. In particular, Sanicro 25 was proven to remain stable for more than 2000 h at 700 • C. Zeng et al [10] investigated the tensile properties, microhardness, chemical composition distribution, and microstructure of the BTi-6431S titanium alloy, which can be used in applications up to 700 • C. Furthermore, Wright et al [11] examined the properties of Alloy 800H and Alloy 617 for nuclear plants and asserted that their operating temperature range was 750-800 • C in the steam generator. Dewa et al [12] also analyzed the fatigue properties of Alloy 617 and stated that its maximum design temperature was 950 • C.…”

The Influence of Long-term Ageing on the Microstructure of Sanicro 25 Steel

“…This steel is characterised by high nickel (24%), chromium (22%) and tungsten (3%) contents and the addition of elements such as niobium, cobalt and copper. It is primarily intended for components of boiler pressure superheaters and reheaters to be operated at up to 700 °C [8].…”

“…HR3C and Super 304H. Creep strength of Sanicro 25 steel determined at 700 º C for up to 100,000 h is 95 MPa, and it is similar to that of the much more expensive HR6W nickel-base alloy [1,8,9]. The high performance of Sanicro 25 steel justifies the increasingly higher demand for it and its more and more widespread use in ultra-supercritical and advanced ultra-supercritical power units [1,9].…”