Research On Ten Straightening Process Model Of Bar Based On Arc Offset Of Neutral Layer

The production of bar has to go through steelmaking,rolling,finishing and other processes.Finishing line is the last process of bar production,and its process control accuracy directly affects the quality of finished bar.As the core equipment of finishing line,the straightening process control of straightening machine directly determines the straightness accuracy of bar,so it is urgent for bar production enterprises to establish a perfect straightening process control model.In view of the above problems,this paper uses theoretical analysis,numerical simulation and experimental verification to do the following research.(1)Based on the theory of plate neutral layer offset,the theory of neutral layer arc offset in bar straightening process is established by discrete method.Every moment of bar in roll system is regarded as pure bending state.The pure bending process of bar is simulated by ABAQUS software,and the neutral layer arc offset formula is fitted based on the numerical simulation data.The three-point bending test is carried out on the press,and the results are obtained Through the comparison of theoretical formula,finite data and experimental data,the correctness of arc-shaped neutral layer migration theory in bar bending is proved.(2)Based on the arc deflection theory of the neutral layer of bar,the elastic recovery theory of one-step bending is deduced;The residual curvature after the first straightening is taken as the original curvature of the second straightening,and so on,the elastic recovery theory of bar ten roll straightening process is established,which can verify the rationality of straightening process parameters.(3)Based on bilinear roll profile design and visual studio 2008 software platform establishes the calculation model of straightening roll profile,which can quickly calculate the parameters range of straightening roll according to the parameters of incoming bar,and set the specific parameters according to the actual situation,and the designed roll profile data can be quickly obtained,so as to provide convenience for the drawing of straightening roll;With the aim of 80% of the contact length between the bar and the straightening roll as the objective,the adjustment method of the bar straightening inclination angle is established by the cyclic iteration method.At the same time,a calculation method of the bar straightness is proposed,which can lay a theoretical foundation for the on-line detection of the straightness.(4)The straightening process of bar was simulated by ABAQUS software,and the straightness,residual stress and straightening force of bar after straightening were obtained.Through the simulation,the straightness of the straightened bar is less than 1 mm / m,which meets the requirements of straightness,and the residual stress is small.Then,the process parameters of a ten roll bar straightener were collected.By comparison,the theoretical calculation bending amount was slightly larger than the actual setting bending amount,and the deviation was about 10%.At the same time,the whole process bending elastic recovery theory was applied to verify the straightening process,and the results showed that the residual deflection was less than 1 mm/m.