Effect of vibration treatment during welding on technological strength of chromium martensitic steel P91

Abstract

The paper shows the possibility of using the technology of vibration treatment in the process of welding of high-temperature chromium steel of martensitic class P91 applied to the product to increase the technological strength of welded joints and the effect of this technology on mechanical properties before and after thermal treatment. Application of vibration action on welding bath and weld seam in process of manufacturing of welded structure may allow to reduce inhomogeneity of weld metal structure in liquid phase, as well as increase its microchemical inhomogeneity within crystallites during crystallization, reduce grain size due to more efficient heat removal and increase of number of crystallization centers. On the example of manufacturing the turbine support housing of the gas turbine drive, it is shown that it is necessary to replace part of the heat treatment operations with other more energy - efficient and less labor-intensive operations. Results of studies of influence of vibration treatment of welded joint on tendency of welded joint metal to form cold cracks, strength, hardness and impact toughness are given. Based on the obtained results, diagrams of average values of parameters are constructed and conclusions are drawn on the possibility of using the technology of vibration treatment of the turbine casing in the process of welding in order to reduce the number of heat treatment operations during its manufacture.

Welding Technology for Liquefied Natural Gas Tanks

“…Optimum parameters of 9% nickel steel are achieved by very precise temperature control during production and controlled quenching. Preheating is performed only if high humidity is condensed on parts or welding works are carried out at temperature below 5 ° C [1,[16][17][18][19].…”

Effect of Different Ultrasonic Power on the Properties of RHA Steel Welded Joints

“…However, in some specific cases, the small deformation caused by vibration can reduce the welding stress [8]. With the change of vibration mode and frequency, low-frequency vibration welding can improve the toughness of welded joints without negative impact on other mechanical properties [9]. It has also been reported that applying an electromagnetic field in the welding process can effectively refine the weld grains and improve the weld hardness but, unfortunately, will weaken some mechanical properties of the weld, including strength and toughness [10,11].…”