The vibratory stress relief of a marine shafting of 35 # bar steel

Abstract

The marine shafting is made from a 35 # bar steel. The 35 # bar steel is named based on PR China national standard GB 699-88, “Quality carbon structure steel technical requirements,” the 35 # bar steel corresponds to 060A35, B.S. The bar steel was hot rolled, piled and air cooled; hot rolling, cooling and microstructure transformation formed macro residual stress in the bar steel. There is high macro residual stress in the 35 # (060A35, B.S.) bar steel. Worker shaped the bar steel into marine shafting with lathe. During machining, the macro residual stress releases and thus causes considerable deformation of the marine shafting. The vibratory stress relief is introduced to the bar steel that was shaped into marine shafting. The vibratory stress relief of the bar steel of the marine shafting was carried out. The tensile properties of the bar steel were measured before and after vibration. While the bar steel was vibrating, six different location axial surface vibratory stresses were measured with dynamic strain gauge; the axial surface vibratory stresses distributive curve is obtained. The macro residual stress was measured with X-ray stressmeter before and after vibration. The macro residual stress decreased notably by about 48%. The tensile properties changed slightly. The vibratory wave is a standing wave. The vibratory stress relief is valid for macro residual stress relieving of the bar steel of the marine shafting. The mechanism of the macro residual stress relieving by vibration on the bar steel of marine shafting is discussed. The “double-dynamic mechanism” is introduced to explain the course of macro residual stress relieving in the test.