越野车车身前支梁内高压成形精度与性能

Tube hydroforming precision and performance on front support beam foroff-road vehicle body

为获得车身前支梁内高压成形工艺稳定性和尺寸一致性的相关数据,对批量生产的上、下前支梁典型截面的尺寸精度、环向壁厚和残余应力分别进行了抽样测量,并对其年度废品率进行了统计分析。结果表明:前支梁典型截面的尺寸精度可达±0.2 mm,离散度均低于0.2%;其壁厚分布均匀,最大减薄率低于6%。成形件母材区的平均抗拉强度大于436.7 MPa,且焊缝区的强度均高于母材区。此外,前支梁成形件的残余应力较小,最大残余拉应力仅为78 MPa,大部分区域处于残余压应力状态,且最大残余压应力达到108 MPa,有利于提高疲劳性能。内高压成形技术可保证前支梁尺寸精度的一致性和高性能成形,且其年度废品率低于0.3%。

In order to obtain the relevant data of the stability and dimensional consistency of tube hydroforming process on the front support beam for the vehicle body,the typical cross-section dimensional precision,circumferential wall thickness and residual stress of the massproduced upper and lower front support beams were sampled and measured,and the annual scrap rate was statistically analyzed.The results show that the typical cross-section dimensional precision of front support beam is within±0.2 mm,the dispersion is lower than 0.2%,the wall thickness distribution is uniform,and the maximum thinning rate is lower than 6%.The average tensile strength in the base metal area of formed part is greater than 436.7 MPa,and the strength in the weld area is higher than that in the base metal area.In addition,the residual stress of front support beam formed part is small,the maximum residual tensile stress is only 78 MPa,most areas are in the state of residual compressive stress,and the maximum residual compressive stress reaches 108 MPa,which is beneficial to improve the fatigue performance.Therefore,the tube hydroforming technology can ensure the consistency of the dimensional precision and the high performance forming of front support beam,and its annual scrap rate is less than 0.3%.