Titanium Alloy Rod Wire Rod Rolling Pass Design And Optimization

Titanium alloy has many outstanding advantages such as low density, highspecific strength, excellent high and low temperature performance, which is akind of structural metal developed in1950’s. Due to its high deformationresistance and low thermal conductivity, titanium alloy rod and wire rolled intraditional two-roll mill will lead to harmful spread easily, which has influenceon low production efficiency and poor product quality. Therefore, titanium alloyrod and wire for making high-end products can’t be met.Aimed at high demand, but backward production techniques of titaniumalloy rod and wire, Taiyuan university of science and technology proposed toproduce titanium alloy rod and wire with three-roll Y-type mill for the first time,which has advantages of high deformation efficiency, available continuousproduction, high yield, and excellent over-all properties. However, workpiecehas poor stability in three-roll pass. That is to say, symmetric axis of workingpiece is found to deviate away from that of multi-roller pass, called as "reversingsteel", which could lead to "roll-seizing" and stop rolling process. Therefore, anappropriate pass system design system is the efficient way to solve suchproblem.To solve these problems above, starting from the characters of three-rollmill, this paper focuses on pass design and optimization of three-roll Y-type mill.And main work is as followed：(1) Pointing to low accuracy of current model in deformation region ofthree-roll mill, new mathematics models for “flat triangle-round triangle”sequence pass system and “arc triangle–round triangle” sequence pass system indeformation region, which are frequently used in three-roll mill, have beenestablished in this paper with mathematics analytical method.(2) Based on all three-roll pass design parameters mathematics modelsabove, computer aided Roll-Pass design (CARD) system of titanium alloy rodand wire has been developed with Matlab, Excel and AutoCAD. (3)Algorithm of Fmincon function (constrained nonlinear N dimensionsminimization) in Matlab optimization toolbox has been applied to optimize passsystem, setting energy consumption minimum as target function and elongationcoefficient as decision parameter.(4) Pass system of Φ12mm and Φ15mm titanium alloy rod (TC4) has beendesigned with CARD system. The rolling experiments have been done inself-developed eight-stand three-roll practical production line, and qualifiedtitanium alloy finished products have been obtained.The result shows that, with the CARD system, pass design can get highprecision, high reliability accurately and rapidly. The CARD system provides asimple, reliable and scientific method for pass design in titanium alloy rod andwire for three-roll mill.