Preliminary application of the draft code case for alloy 617 for a high temperature component

Abstract

The ASME draft Code Case for Alloy 617 was developed in the late 1980s for the design of very-high-temperature gas cooled reactors. The draft Code Case was patterned after the ASME Code Section III Subsection NH and was intended to cover Ni-Cr-Co-Mo Alloy 617 to 982qC (1800qF). But the draft Code Case is still in an incomplete status, lacking necessary material properties and design data. In this study, a preliminary evaluation on the creep-fatigue damage for a high temperature hot duct pipe structure has been carried out according to the draft Code Case. The evaluation procedures and results according to the draft Code Case for Alloy 617 material were compared with those of the ASME Subsection NH and RCC-MR for Alloy 800H material. It was shown that many data including material properties, fatigue and creep data should be supplemented for the draft Code Case. However, when the evaluation results on the creep-fatigue damage according to the draft Code Case, ASME-NH and RCC-MR were compared based on the preliminary evaluation, it was shown that the Alloy 617 results from the draft Code Case tended to be more resistant to the creep damage while less resistant to the fatigue damage than those from the ASME-NH and RCC-MR.

Effect of Strain Range on the Low Cycle Fatigue in Alloy 617 at High Temperature

“…Therefore, a thorough knowledge of the elastoplastic behavior is necessary in the design and life evaluation of such components that operate in the high temperature condition. Although Alloy 617 has many superior properties, many researchers have reported that the number of cycles to failure varies widely at high temperatures [5][6][7][8][9]. However, they did not provide sufficient data on the Alloy 617 in the LCF regime over a range of conditions.…”

Preliminary Design Analysis of a Hot Gas Duct for the NHDD Program at Korea

“…A preliminary evaluation for a creep-fatigue damage according to the draft code case was carried out on a hot duct piping for the Alloy 617 material. Then the creep-fatigue damage equation for the Alloy 617 material according to the draft code case was calculated as [9] 18.8 82732…”

“…An evaluation for creep-fatigue damage according to the ASME-NH was carried out for the hot duct piping for the Alloy 800H material. Thus the creep-fatigue damage equation for Alloy 800H according to the ASME-NH calculation was calculated as [9] Advanced Materials Research Vols. 33-37 42.4 396.9…”

“…In RCC-MR, the elastic-plastic strain is determined from a summation of four strain terms; elastic strain range, plastic increase in a strain due to a primary stress range, plastic increase in a strain according to Neuber's rule and a plastic increase in a strain due to a triaxiality. Thus the creep-fatigue damage equation for Alloy 800H according to the RCC-MR is [9] 970.4 270.5…”