Development of a New High-Performance Martensitic Heat-Resistant Steel for Boiler Applications

Abstract

The realization of advanced thermal power plants with increased efficiencies requires the development of new materials with enhanced capabilities in respect to high temperature strength and steam oxidation behavior. The change in the environmental policy and the increasing contribution of renewable energy sources into the public electric grid has changed the operation mode of the existing power plants in Europe. Instead of quasi stationary operation, for which the conventional thermal power plant fleet was designed, cyclic operation modes will dominate the power plant service lifetime. The creep-fatigue phenomena, however, may be responsible for significant lifetime reductions compared with the original design lifetime. Revamping of the existing power plants by application of “stronger” materials with improved steam-oxidation behavior, allowing wall thickness reduction can be a possible way to address the topic. Recently, Vallourec developed a new high-Cr ferritic-martensitic steel that combines excellent creep rupture strength properties and enhanced steam oxidation resistance of 12%Cr steels such as VM12-SHC or X20CrMoV11-1. Industrial products were successfully manufactured and the creep and steam oxidation properties were validated.

Science and Technology of High Performance Ferritic (HiperFer) Stainless Steels

“…10 the creep strength of the HiperFer 17Cr2 steels is ranked against various state of the art power engineering structural grades. Cold-rolled and recrystallization + precipitation annealed (RX+PA) 17Cr2/3 surpasses grade 92 [57] and approximately matches the performance of the novel 12 Cr steel Super VM12 [58]. While creep deformation of intermetallic particle strengthened HiperFer is controlled by growth of the strengthening Laves phase precipitates [16,47,59,60], creep damage and failure are mainly related to the accumulation of plastic deformation in PFZs (cf.…”

“…Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 7 March 2020 doi:10.20944/preprints202003.0120.v1 [57]; MarBN, mean of [61] and [62]; Super VM12 [58]; experiments marked with arrows are still in progress) Fig. 11: Accumulated plastic deformation, causing sub-grain formation (cf.…”

Science and Technology of High Performance Ferritic (HiperFer) Stainless Steels

“…In Figure 10 the creep strength of the HiperFer 17Cr2 steels is ranked against various state of the art power engineering structural grades. Cold-rolled and recrystallization + precipitation annealed (RX + PA) 17Cr2 surpasses grade 92 [57] and approximately matches the performance of the novel 12 Cr steel Super VM12 [58]. While creep deformation of intermetallic particle strengthened HiperFer is controlled by growth of the strengthening Laves phase precipitates [16,47,59,60], creep damage and failure are mainly related to the accumulation of plastic deformation in PFZs (cf.…”

“…steel Super VM12 [58]. While creep deformation of intermetallic particle strengthened HiperFer is controlled by growth of the strengthening Laves phase precipitates [16,47,59,60], creep damage and failure are mainly related to the accumulation of plastic deformation in PFZs (cf.…”

“…Creep rupture strength of HiperFer 17Cr1/2 and 17Cr5 in comparison to state of the art AFM and austenitic steels (100 MPa cross-weld data courtesy of Y. Yamamoto, ORNL, USA; comparative creep strength data: grade 92, 316L[57]; MarBN, mean of[61] and[62]; Super VM12[58]; experiments marked with arrows are still in progress).…”