Optimum Thread Rolling Process that Improves SCC Resistance.

Kephart, A. P.

Technical Information Center Oak Ridge Tennessee

关键词: Alloys;    Steels;    Stress corrosion;    Heat treatments;    Ammonium nitrates;   

RP-ID  :  DE2004821687

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

Accelerated testing in environments aggressive for the specific material have shown that fastener threads that are rolled after strengthening heat treatments have improved resistance to SCC initiation. For example, intergranular SCC was produced in one day when machined (cut) threads of high strength steel (ASTM A193 B-7 and A354 Grade 8) were exposed to an aggressive aqueous environment containing 8 weight % boiling ammonium nitrate and stressed to about 40% of the steel's yield strength (120 ksi, 827 MPa). In similar testing conditions, fasteners that had threads rolled before heat-treatment (quench and temper) had similar susceptibility to SCC.