Toughness weld metal

The use of a bottom flange RBS combined with the replacement of top and bottom beam flange groove welds with high toughness weld metal provided plastic rotations on the order of 0.02 to 0.025 radian. The presence of a... 

J. O Donnell, H. Huthmann, and A. A. Tavassoli, The Fracture Toughness Behavior of Austenitic Steels and Weld Metal Including the Effects of Thermal Aging and Irradiation , Int. J. Pres. Ves. Piping, 65 (1996), 209-220. 

The requirements for obtaining the desired notch toughness in weld metal are more comprehensive. Impact tests are required on the weld metal of procedure qualification test plates for all... 

Step 3 Decide combined thickness of joint in question (Chapter 3). Step 4 Decide limitations on heat input, bead size, or electrode size which can he used (Chapter 3). These limitations may arise because of positional welding or because of a need to achieve minimum toughness levels in weld metal or HAZ. Step 5 Trace horizontal line to obtain required preheat level. 

The ability of a material containing a sharp defect, such as a crack tip, to resist fracture (or crack growth] when stressed. The fracture toughness of steels (and weld metals] is reduced when the temperature is reduced and also near ambient temperature when they... 

Normally, a minimum preheat temperature is required when it is necessary to achieve particular levels of toughness and/or strength in the HAZ or weld metal a maximum value may also be required. Preheat may be local or general. It is recommended that the former should be measured at least 75 mm from the weld line. 

The weldability of the Fe-12Ni-0.5Al alloy is illustrated in Fig. 3, where the ratios of toughness for either weld metal or the heat-affected zone (HAZ) to that of... 

Use of higher-purity filler wire in welding the 3- and 8-mm-thick plates with square edges had little effect on the joint strength, but the weld metal had a higher ductility and toughness. 

Test specimens for conducting mechanical property tests such as Charpy V-notch, tensile and fracture toughness for weld metals and base metals. 

Table 4.5 gives an example of the content of capsules of 900 MWe reactors. Charpy V-notch tests are used to monitor all the materials. Additional tensile and fracture toughness tests are carried out for base and weld metals. Most reactors have four surveillance capsules to cover their design lifetime (40 years), except the first series of six 900MWe reactors known as CPO which have eight capsules. Generally, capsules are planned to be removed so that irradiation at quarter, half, three-quarters and completion of the component design end-of-life fluence can be achieved (Brillaud and Hedin, 1992 Chas et al, 2004). Table 4.6 shows the lead factors, defined by... 

C J Bolton, P J E Bischler, M R Wootton, R Moskovic, J R Morri, H C Pegg, A B Haines, R F Smith and R Woodman, Fracture toughness of weld metal samples removed from a decommissioned Magnox reactor pressure vessel, Int. J. Press. Vessels Pip., 2002,79,685-692. 

Plots showing effects of irradiation on crack-arrest toughness, /C a, vs temperature for HSSI weld 73W, the same weld metal as in Fig. 10.9a (Iskander et al., 1992). 

As shown, the AT4U and ATo are essentially 1 1 for weld metals, but ATo is 1.16 X AT41J for base metals. These correlations are based on 42 and 47 individual sets of data, respectively and, as reported in Sokolov and Nanstad (1999), the raw CVN data and the raw Kj data were obtained and analyzed by the authors to ensure consistency. It is important to note that the confidence bounds ( 2o) on these correlations are 26 °C and 36 °C for the welds and base metals, respectively. As discussed by the authors, correlative evaluations using other CVN energy indices did not significantly alter the observations. Figure 10.15 (Sokolov and Nanstad, 1999) shows a comparison of the CVN 41J transition temperature and the fracture toughness reference temperature To for the same materials as in Fig. 10.14, and shows the relationship ... 

Comparisons of irradiation-induced shifts of fracture toughness and CVN energy for western-type RPV (a) weld metals and (b) base metals. As shown, the A74U and ATo (= T m) are essentially 1 1 for weld metals, but ATg is 1.16 x ATnj for base metals (Sokolov and Nanstad, 1999). 

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