Stress relaxation behavior for low alloy heat resistance steel

摘要

Stress relaxation behavior was experimentally investigated for low alloy heat resistance steel used in thermal well casing at elevated temperature.The experimental results indicated that stress relaxation occurred, particularly, pre-stress decreased sharply at early stage, followed by constant stresss, i.e.s, stress relaxation limitation at 350 °C.When applied pre-stress 760 MPa, the relaxation limitation was close to 392 MPa approximately.Furthermore, relaxation limitation decreased significantly with pre-strain reducing.As applied pre-strain 230 MPa, the relaxation limitation reached to 0.1 MPa.In other word, pre-strain disappeared.It is suggested that pre-stress plays a negligible role in well cementation for thermal recovery well due to stress relaxation.