creep fracture in tempered martensitic steels
Jan 28, 2020 · Also, in sample, creep tested in as-received state with 100 MPa at 625 °C, the HAZ microstructure consisted of well-tempered martensitic islands converted to colonies of spheroidal precipitates with fine ferrite subgrains, surrounded by larger recrystallized ferrite blocks, the last containing very low dislocation density (Fig. 43). Effects of Tempering Temperature on the Microstructure and Aug 04, 2018 · Creep curves for steels tempered at 660, 690 and 740°C - Tensile strength 175 MPa and test temperature 600°C. According to the results, it was observed that the variation of the test load reduced the rupture time by 37% of sample tempered at 660°C, 41% in
Keywords:martensitic steels, welded joints, creep behaviour, failure mode, fracture mechanism INTRODUCTION High chromium (9-12% Cr) martensitic-ferritic creep-resistant steels represent promising materials for use in ultra-super-critical (USC) thermal power plants . Recent Investigation on creep behavior of welded joint of Dec 12, 2014 · The tempered martensite boundaries in the HAZ gradually become obscure after creep, shown in Fig. 8(h). Due to the lowest peak temperature and the shortest dwell time at peak temperature during welding in this area (OT-HAZ), a large amount of undissolved carbides which are apt to become coarse and stimulate the nucleation of creep voids Mechanisms of tempered martensite embrittlement in slow cooling alloy steels, previously tempered above 600~ in the temperature range 350 to 550~ (temper embrittlement), and ii) tempering as-quenched alloy steels in the range 250 to 450~ (tempered martensite embrittlement). Whereas there is now a large body of evidence linking the phenomenon of temper embrittle-
of the steel. Creep rupture strength of the high Cr ferritic steel decreases quickly after long-term use. A signicant im-provement of creep rupture strength can be achieved if we can prevent the loss of rupture strength. In the steel tempered at high temperature, enhanced recovery of the subgrain structure along grain boundaries isCreep failure model of a tempered martensitic stainless A new model considering both deformation and damage evolution under multiple viscoplastic mechanisms is used to represent high temperature creep deformation and damage of a martensitic stainless steel in a wide range of load levels. First, an experimental database is built to characterise both creep flow and damage behaviour using tests on various kinds of specimens.