Assessment of creep rupture properties for dissimilar steels welded joints between T92 and HR3C

Abstract

A B S T R A C T Dissimilar steels welded joints, between ferritic steel and austenitic stainless steel, are always encountered in high-temperature components in power plants. As two new grade ferritic steel and austenitic stainless steel, T92 (9Cr0.5Mo2WVNb) and HR3C (TP310HCbN), exhibit superior heat strength at elevated temperatures and are increasingly applied in ultra-supercritical (USC) plants around the world, a complete assessment of the properties for T92/HR3C dissimilar steels welded joints is urgently required. In this paper, metallographic microstructures across the joint were inspected by optical microscope. Particularly, the creep rupture test was conducted on joints under different load stresses at 625 • C to analyse creep strength and predict their service lives, while their fractograph were observed under scanning electron microscope. Additionally, finite element method was employed to investigate residual stress distribution of joints. Results showed that the joints were qualified under USC conditions, and T92 base material was commonly the weakest part of them.

Effect of multiaxial stress state on creep damage in ASME T92 welded joint

“…By raising the steam temperature up to 600°C, the economic efficiency of generating units can be increased remarkably. Compared with supercritical units, USC units can afford a 4% to 7% increase in heat efficiency (from 40% to 45%‐47%) as well as a 20% to 25% reduction in the carbon dioxide emission . Hence, materials with superior creep and oxidation resistance are required to meet the demands of such severe service conditions …”

“…Compared with supercritical units, USC units can afford a 4% to 7% increase in heat efficiency (from 40% to 45%-47%) as well as a 20% to 25% reduction in the carbon dioxide emission. 2 Hence, materials with superior creep and oxidation resistance are required to meet the demands of such severe service conditions. 3 ASME T/P92 martensitic heat resistant steel (9Cr-1.8W-0.5Mo-NbV), developed by the Nippon Steel Corporation of Japan, has been widely recognized as an ideal material for USC components, since it possesses considerably high creep resistance, low oxidation rate, and well-welding performance.…”

Failure Analysis of Shaft Circulating Water Pump (CWP) used in Power Plant

“…Consequently, a comprehensive failure analysis including a variety of characterization methods was conducted to identify the root cause based on our previous failure analysis experiences [5][6][7][8][9][10][11][12][13].…”

A Comparison of Creep Rupture Strength of Ferritic/Austenitic Dissimilar Weld Joints of Different Grades of Cr-Mo Ferritic Steels

“…[1] However, premature creep failure is encountered in such dissimilar weld joints. [2][3][4][5][6][7] An understanding of the microstructural changes across the weld interface between ferritic and austenitic alloys and their effects on high-temperature creep deformation and fracture behavior are of primary concern for a realistic life assessment of the dissimilar weld joints. [8][9][10][11][12][13][14][15][16][17] Furthermore, the combination of material, geometry, and size of the weld joint and loading conditions can lead to the presence of complex stress state across the joint, which greatly influences the creep rupture life of dissimilar weld joints.…”