Welding residual stress test and fatigue life experiment on 16MnR specimens welded by high-temperature welding process were studied in this article. It was indicated that the process could decrease welding residual stress and increase fatigue life dramatically. The maximum of the longitudinal residual stress of specimens welded by high-temperature welding process at 750 ℃ and 850 ℃ were decreased by 55% and 68%, respectively, and the fatigue life of specimens welded by high-temperature welding process at 750 ℃ and 850 ℃ was decreased by 50% and 98%, respectively, as compared with those of the specimens welded by normal-temperature welding process. The reason for the advantages of the high-temperature welding process was analyzed, and demonstrated its feasibility.

    Performance test of heat transfer and pressure drop was done in the helical baffle heat exchangers with helix angle of 12°,18°, 30°and 40°.Applying a software Tasc3 o f British Heat Transfer Association, the operation situation of heat exchangers of segmental baffle board was simulated , and the value of heat coefficient and pressure drop was obtained.Through data computation, under the same flow quantity , the overall coefficient per pressure drop of helical baffle board heat exchangers with different helix angles was compared with those of segmental baffle board heat exchangers.Meanwhile , the coefficient at shell side and the pressure drop were studied contrastively for different helix angles of 12°, 18°, 30°and 40°, and helix angle w as optimized .The results show that the overall heat coefficient of helical baffle board heat ex changers in our tests is higher 59.48% than that of segmental baffle board heat ex changers of corresponding structures.Under the test condition, the general performance of baffle heat exchanger with helix angle of 18? is better than baffle heat exchanger with helix angle 12°, 30°and 40°.