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Title: Fracture toughness characterization of Type 410 stainless steel: Final report

Technical Report ·
OSTI ID:5747016

Type 410 stainless steel has been used as an alternative material for bolts and studs because of its mechanical properties and corrosion resistance. However, failures have occurred in 410 stainless steel that have prompted further studies to characterize the properties of the failed material. After the discovery of failed valve studs by Virginia Power, investigation of the failures focused on improper heat treating of the studs, resulting in temper embrittlement. (The studs were purchased to ASTM specification A 193 Grade B6, with a supplemental requirement of 125 ksi tensile strength.) To assess the fracture properties of the stud material, pieces of several failed studs were sent to Materials Engineering Associates, Inc. Characterization of the material was performed using impact tests (Charpy-V notch specimens), strength tests (tensile specimens), and static fracture toughness tests (compact tension specimens). The strength tests revealed 0.2% offset yield and ultimate strengths exceeding ASTM and Virginia Power requirements, although the reduction-of-area requirement was satisfied in only three of six tests. The impact tests revealed low toughness, with 20 ft-lb and 20% shear not eclipsed until 430/sup 0/F. Test results at 550/sup 0/F indicate an upper shelf in excess of 80 ft-lb. The static fracture toughness tests exhibited cleavage failure from 40/sup 0/F to 200/sup 0/F, with low toughness at 40/sup 0/F and 120/sup 0/F. Higher toughness was observed at 200/sup 0/F, with the onset of the static upper shelf probably occurring between 300/sup 0/F to 400/sup 0/F. 2 refs., 10 figs., 4 tabs.

Research Organization:
Materials Engineering Associates, Inc., Lanham, MD (USA)
OSTI ID:
5747016
Report Number(s):
EPRI-NP-5511; ON: TI88920111
Country of Publication:
United States
Language:
English