Rolling Speed And Model For Micro-tracking Of Tailor Rolled Blank

Low carbon and environmental protection are being paid more and more attention, lightweight becomes a important method of energy saving in automobile industry. Tailor welded blanks (TWB) have been applied in auto manufacturing as an advanced lightweight technology, but there are some disadvantages in TWB:longer production process, increasing the cost, welding seams effecting the surface quality, no linear sheet thickness transitions. A more effective method is Tailor Rolled Blank (TRB) by changing roll gap during rolling, and TRB can make smooth linear thickness transitions, integrating the thin and thick region.In this paper, TRB transition region was main research object, the longitudinal and lateral speed were deeply analyzed, and based on that a micro-tracking model was designed.(1)Three power function expression of transition region curve was derived. The shape and size of curve not only determines the local carrying capacity of stamping, but also affect stamping production and die design, and also has close relation with rolling process control level. The expression optimized the transition region curve and smoothed the connected point.(2)The matching relation between longitudinal speed and lateral speed when rolling transition region was researched, and specific expressions of these two speeds was calculated according to the matching relation. The control of the two speeds decided the degree of fit between designed transition region curve and rolled transition region curve. On the condition of mass flow, longitudinal speed and lateral speed could be expressed.(3)The control method of rolling TRB was proposed. Longitudinal speed was different when rolling thick region, thin region and transition region, so was lateral speed. A new speed control method was proposed on the whole TRB rolling process based on speed periodic variation.(4)A micro-tracking model was developed. When rolling TRB, the longitudinal changes in thickness are continuous. The model concluded three parts:starting point of tracking; rolling process tracking and judging the end of one periodic rolling which could accurately track the location of rolling.According to rolling speed control method and micro-tracking model mentioned above, rolling experiment results showed:the differential thickness ratio up to1:1.7, the transition region can be controlled within100-200mm. Thick, thin areas and the length of the transition region could be accuracy gained.