The Affects Of Manufacturing Process On Torsion Property Of Bead Wire And Its Optimization

Bead wire is the frame material of tire,it used to fix the connection between wheel hub and carcass,during the vehicle’s running,especial in bad weather and road condition,the tire will bear drastic force,and the stress will forcus on tire bead area,if the property of wire is not good enough,it will bring tire broken,it is a big quality risk.The bead wire should have strong tensile and good ductility which is ensure the usage of it,and most important ductility property is bead wire torsion.Ф1.55 mm HT was taken as an example to implement the trials,choose the most important factors,carbon equivalent(CE%),drawing angle and termper temperature,which will effect the bead wire torsion significantly,implement DOE to find the main factors.Via the trial,CE% have the biggest influence to torsion,higher CE% lower torsion.The bead wire from 0.87 wt% wire rod is much higher than the bead wire from 0.82 wt% wire rod.The potential reason is because the higher carbon content will bring higher risk of GBC which have bad influence to the torsion property.Drawing angle also have big influence to torsion,bigger drawing angle,lower torsion.The bead wire produced with 6° die angle will have better torsion property than 12°,the reason is because the smaller die angle will make the wire deformation more homogeneous,it will help to improve the torsion property.The influence to torsion of temper temperature is limited in defined temperature region,the torsion property between 420℃ and 470℃ is not significant.The experimental results were explained and,the process parameters were also optimized based on the result of the DOE.The best process setting should be using 0.80~0.845 wt% wire rod,choose 6° drawing die angle,select 420℃ tempering temperature,after optimization,the property of bead wire is more stable,and unqualified ratio decreased from 18% to almost zero.