Abstract:
      Low carbon steel plates with fine grained ferrite in surface layers industrially produced by a special thermo-mechanical control process (TMCP) were tested for investigating the effect of ferrite grain refinement on fatigue behavior of the steel plates. And fatigue fractographs were observed and analyzed with the scanning electron microscope (SEM). For the plates rolled by the special TMCP (named special plates), the ferrite grain size approaches 10micron in surface layers and reaches 14micron in average while for the usually rolled plates (named usual plates), the grain size is 26 micron in surface layers and 26.4 micron in average. In a similar stress condition, the fatigue lifetime of the special plates is more than 3.5 times as long as that of usual plates, and the first stage of fatigue crack propagation can be prolonged, and the secondary fatigue cracks are smaller than that of usually hot-rolled plates. With the lifetime 37% more than that of usual plates, the special plates can sustain a stress range 40MPa more than that the usual plates can sustain. Therefore, the fatigue properties have been obviously improved for the special plates with fine grains in surface layers.

Keywords:low carbon steel plate; ferrite grain refinement, surface layers; fatigue strength
原文下載鏈接http://www.maneyonline.com/doi/abs/10.1179/174328405X42965?journalCode=mst