Analysis of factors responsible for the accelerated creep rupture of 12% Cr martensitic steel weld joints

Microstructure Evolution and Mechanical Properties of X6CrNiMoVNb11-2 Stainless Steel after Heat Treatment

“…The Ac1, Ac3, Ms and Mf can be determined through the verification of the experimental phase transition point [31,32]. Figure 4a shows the transition temperatures (Ac1 = 774.77 °C, Ac3 = 851.21 °C, Ms = 292.71 °C and Mf = 133.95 °C) from the measured length of the sample by the dilatometer, by heating to 1040 °C for 30 min and cooling at a rate of 1.0 °C/s, which are close to the values of Ac1 = 774.00 °C, Ac3 = 861.00 °C, as taken from reference [35]. Since the specific volume of austenite is smaller than that of martensite, the rapid expansion of the specimen at the Ms point during the transformation from austenite to martensite is observed near 292.71 °C.…”

“…Using the thermal expansion curve, the temperatures of the beginning time The A c1 , A c3 , M s and M f can be determined through the verification of the experimental phase transition point [31,32]. Figure 4a [35]. Since the specific volume of austenite is smaller than that of martensite, the rapid expansion of the specimen at the M s point during the transformation from austenite to martensite is observed near 292.71 • C. According to Figure 4a, the sample length firstly increases linearly and then decreases, indicating an austenite transformation at the inflection.…”