By using SolidWorks2010 software 3d entity modeling for the engine crankshaft of the developed tobacco harvest machine was built, and Ansys system combining working conditions to crankshaft with Ansys finite element method was imported. Then the crankshaft's stress result figure in four conditions was got, the stress concentration area was found, comparing and the analysis the the working conditions of the results, thus the basis theory for the engine of the crankshaft structure optimization design and research was provided.

In this study, 45 carbon steel was boronized and borosulphurized at 950°C for 2, 3， 4, 5, 6 and 8 h, respectively. The samples were characterized by scanning electron microscopy, optical microscope, microhardness tester and ring-on-block wear tester. It is found that the surface of borosulphurized samples was dense, compact and relatively smooth; Although the boride layers produced by boro- sulphurizing at 950°C showed a lower microhardness value compared with that produced by boronizing, the wear resistance of the borosulphurized carbon steel is higher than that of boronized sample due to formation of FeS phase in the boride layer.