Charpy shelf energy

There is a well-known relationship between the volume fraction of second-phase particles (inclusions) and the ductility as measured by the strain at the fracture (or percentage reduction of area) in a tensile test. As a typical example, fig. 7 shows the effect of volume fraction and shape of a second phase on the ductility and Charpy shelf energy. It is clear that the ductility is adversely affected by an increasing volume fraction of... 

Fig. 7. Effect of volume fraction and shape of second phase on the ductility and Charpy shelf energy.

The most dramatic results were, however, the complete elimination of cracking of the test plates when they were bent over a sharp radius in the transverse direction. Figure 12, and the more than doubling of the transverse shelf energy as measured by 2/3 Charpy tests. Figure 13 ( ). The latter also shows the progressive improvements with incremental additions of REM s. 

AR431 1.161 Evaluation of reactor pressure vessels with Charpy upper-shelf energy less than 50 ft-lb... 

B W used similar ASA welding techniques to those just described for C-E. In the years during which B W fabricated RPVs, few changes were made in the welding procedures. In fact, B W used a relatively small number of different weld wire/flux lot combinations. All of the RPV welds produced by B W were made with Linde 80 flux type. Due to the smaller number of different weld wire/flux lots used by B W, many RPVs were made with the same specific weld number. There are many commonalities between the Linde 80 flux type welds in the B W-fabricated RPVs. One unfortunate feature of these welds is the low Charpy upper-shelf energy. The Linde 80 welds made by B W are considered as one class of welds, since there are characteristics common to all these welds. 

Notch Impact toughness Energy Lateral expansion % shear fracture Dynamic T41J/ Vk, Tq3j, use To,89 mm 7 50% Blunt Charpy V-notch (CVN) impact test e.g., ASTM E 23, EN ISO 148. Obtain curve fit to data vs test temperature, determine various transition temperature indices, e.g., T41J, and upper shelf energy (USE). Initiation and propagation test ... 

In accordance with 10 CFR 50 Appendix G, Paragraph IV A, the reactor vessel beltline materials have minimum upper-shelf energy, as determined from Charpy V-notch tests on unirradiated specimens in accordance with Paragraphs NB-2322.2(a) of the ASME Code, of 75 ft-lbs. Charpy impact tests will be performed on... 

The Charpy V-notch (Cv) upper shelf energy level, in the "weak" (Wr) direction, as obtained per ASTM-A-370 will be no less than 50 ft-lb. A minimum of three Cv specimens will be tested from each plate or forging. 

As a typical example, fig. 8 illustrates the effect of rare earth addition on toughness the impact curves are plotted for both longitudinal and transverse Charpy V-notch specimens (Luyckx et al. 1970). In longitudinal specimens, the impact energy at 100% shear, commonly called the shelf energy, is in excess of 5.5 kg m (40 ft lb) in transverse specimens, it is 2kgm (15 ft lb), which is doubled to 4kgm at the Ce/S ratio of 1.5-2.0. 

On the other hand, it is reported that high transverse impact values can be achieved when the R/S ratio is greater than 4 (Waudby 1978). Ackert and Crozier (1973) have shown that the improvement in the Charpy V-notch shelf energy at -18"C occurs at an R/S ratio of 5 to 6 which is much higher than those described above. Ballance and Mintus (1972) have also shown that a marked improvement in the bend performance of steels is obtained at R/S ratios higher than 4. The difference in R/S ratios reported by various... 

Estimation of fracture toughness from upper-shelf charpy energy and its use in fracture assessment Stress... 

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