Total Hemispherical Emissivity of Grade 91 Ferritic Alloy with Various Surface Conditions

Azmeh, Christopher B.; Walton, Kyle L.; Ghosh, Tushar K.; Loyalka, Sudarshan K.; Viswanath, Dabir S.; Tompson, Robert V.

doi:10.13182/nt15-54

Cited by 8 publications

(5 citation statements)

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“…The total hemispherical emissivity of A387 Grade 91 EDM cut as a function of temperature is shown in Figure 6.1. The total hemispherical emissivity data from Azmeh et al 35 for mild-abrasive A387 Grade 91 are also included. The emissivity of A387 Grade 91 EDM cut has increased from 0.57 to 0.65 in range of temperatures between 444 K and 1026 K. The total hemispherical emissivity values for A387 Grade91 EDM cut were higher than the emissivity values of mild-abrasive A387 Grade 91 in Azmeh et al 35 work.…”

Section: Resultsmentioning

confidence: 99%

“…The total hemispherical emissivity data from Azmeh et al 35 for mild-abrasive A387 Grade 91 are also included. The emissivity of A387 Grade 91 EDM cut has increased from 0.57 to 0.65 in range of temperatures between 444 K and 1026 K. The total hemispherical emissivity values for A387 Grade91 EDM cut were higher than the emissivity values of mild-abrasive A387 Grade 91 in Azmeh et al 35 work. This can be ascribed to oxidation occurring during EDM cutting method from the heat generated.…”

Section: Resultsmentioning

confidence: 99%

“…The total hemispherical emissivity values are given in Figure 6.4. The emissivity data for Azmeh et al 35 for sandblasted surfaces with 60 and120 grit size are included. The emissivity values of sandblasted surface with 320 grit size increased from 0.49 at 464 K to 0.57 at 1048 K. As illustrated in Figure 6.4, the total hemispherical emissivity of sandblasted surfaces increased with finer grit size used.…”

Section: Resultsmentioning

confidence: 99%

“…Azmeh et al (2016) 35 obtained the total hemispherical emissivity of A387 Grade 91 at temperature range from 325 K to 1299 K for different surface circumstances.…”

Section: Emissivity Of A508/a533b and A387 Grade 91mentioning

confidence: 99%

“…26,36,[40][41][42][43] There have been a number of studies demonstrating the effect of oxidation on the total hemispherical emissivity of various materials. 25,35,44,45 The emissivity of SS316L for different surface conditions has been measured by several authors. The literature on emissivity measurements of SS316L has reviewed in chapter two.…”

Section: Introductionmentioning

confidence: 99%

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Total hemispherical emissivity of reactor pressure vessel candidate materials : SS 316 L, SA 508, and A 387 Grade 91

Al-Zubaidi¹

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Future nuclear Reactor Pressure Vessels (RPV) require high emissivity materials and alloy for efficient heat decay removal under normal and accidental events. Emissivity is the material property that determines the heat radiation rate from the material surface. The total hemispherical emissivity of candidate materials, 316L stainless steel, A508/A533B steel, and A387 Grade 91 steel were measured in the present work. Standard ASTM C835-06 was used to measure the total hemispherical emissivity of structural materials of RPV. The bell jar emissivity was measured using 304 stainless steel strips coated with black paint (Aremco HiE-Coat 840 M). Testing these strips verified that the internal bell jar emissivity is greater than 0.8 as required by the ASTM standard. Emissivity of 316L stainless steel was measured for the following conditions: (1) "as-received" from the supplier (un-oxidized) and; (2) oxidized in air at 573 K for up to 3000 h. The emissivity of as-received test strips varied from 0.24 at 434 K to 0.34 at 1026 K. The total hemispherical emissivity of 316 L stainless steel oxidized in air for 500 h or more ranged from 0.28 at 429 K to 0.38 at 1096 K. Increasing the sample oxidation time beyond 500 h at 573 K did not have any significant observable effect on the total hemispherical emissivities of any of the test strips studied. It is suspected that the emissivity ceased to increase during the additional oxidation time because of the protective chromium oxide layer formed on 316L stainless steel inhibiting further oxidation. The total hemispherical emissivity of A508/A533B steel was measured in the temperature range from 400 K to 900 K for the following surface conditions: (1) mirror polished finish; (2) mirror polished and oxidized in air at 573 K and 773 K for various durations; (3) after Electric Discharge Machining (EDM) cutting process; and (4) EDM and oxidized in air at 573 K and 773 K up to 1000 h. The emissivity of polished A508/A533B (un-oxidized) strips varied from 0.16 to 0.24 within the temperature range from 552 K to 1180 K. Emissivity values for polished samples oxidized in air for 10 h at 573 K were increased from 0.18 at 543 K to 0.28 at 815 K. While the emissivity of polished samples oxidized in air for 100 h at 573 K increased from 0.16 at 460 K to 0.33 at 815 K. The total hemispherical emissivity of EDM cut and oxidized in air at 573 K for 500 h has experienced an increase from 0.75 to 0.8 in the range of temperature from 418 K to 625 K. No further significant change in emissivity was observed following an increase in oxidation time from 500 h to 1000 h. Polished and oxidized strips at temperature 773 K for 10 h has increased from 0.74 at 464 K to 0.81 at 838 K. This strong effect of temperature has not been noticed for EDM-cut oxidized samples at 773 K for 500 h due to detach of the oxide layer from the A508/A533B substrate. The emissivity of A387 Grade 91 was measured for the following conditions: (1) EDM cut; (2) EDM cut and oxidized in air at 873 K and 1023 K for up to 5 h; (3) sandblasted with 320 grit size; and (4) sandblasted with 320 grit size and oxidized in air at 1023 K for 5 h. The emissivity of EDM cut A387 Grade 91 varied from 0.57 at 444 K to 0.62 at 1026 K, while the emissivity of A387 Grade 91 sandblasted with 320 grit increased from 0.49 at 464 K to 0.57 at 1048 K. The total hemispherical emissivity of A387 Grade 91 oxidized in air at 873K for 1 h has increased from 0.75 to 0.8 in the temperature range of 420 K to 831 K. The emissivity of A387 Grade 91 oxidized in air at 1023 K for 1h increased from 0.69 at 429 K to 0.8 at 889 K. Oxidation of A387 Grade 91 in air at 873 K and 1023 K did not result in significant difference in emissivity values among various test strips for oxidation durations of 1 h, 3 h, and 5 h. The emissivity of A387 Grade 91 sandblasted with 320 grit and oxidized at 1023 K for 5 h increased from 0.63 at 440 K to 0.74 at 944 K.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…Azmeh et al (2016) 35 obtained the total hemispherical emissivity of A387 Grade 91 at temperature range from 325 K to 1299 K for different surface circumstances.…”

Section: Emissivity Of A508/a533b and A387 Grade 91mentioning

confidence: 99%