Strength tests of type 308 weld metals and welded joint of type 9Cr steel forging at elevated temperature (I)

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High temperature strength tests were carried out on weld metals of type 308 stainless steel welding materials, and welded joint of type 9Cr steel forging in order to get material data and to demonstrate the integrity of welded joints of the structural materials for the demonstrated LMFBR. Test items for type 308 stainless steel weld metals by Gas Tungsten Arc Welding(GTAW) and by Shielded Metal Arc Welding (SMAW), are tensile test, creep test, creep rupture test, low cycle fatigue test, creep-fatigue test and relaxation test. Test items for welded joint of type 9Cr steel forging by GTAW are tensile test, creep test, creep rupture test and creep crack propagation behavior test. As the results of each test, material properties of each weld metal and welded joint were clarified as follows. (1)0.2% off-set yield strength of type 308 stainless steel weld metal by GTAW and SMAW at room temperature, 450C, 500C, 550C and 600C is much higher than that of base metal, and tensile strength at each temperature is equivalent to that of base metal. Creep strength at 500C, 550C and 600C is equivalent to the best fit curve of base metal. Low cycle fatigue strength at 500C and 550C is equivalent to that of base metal. Additionally relaxation properties at 500C and 550C were clarified. These obtained results show that material properties of type 308 stainless steel weld metals by GTAW and SMAW satisfy with each strength value of base metal by "High Temperature Structure Design Standard for LMFBR, Material Standard". (2)As the results of tensile tests for welded joint of Mod.9Cr-1Mo steel forging by GTAW, tensile strength of weld metal is equivalent to existing data and tensile strength of welded joint is equivalent to that of base metal at room temperature, 450C, 500C and 550C. Creep strength of weld metal and welded joint at ...