Six-axis free bending and twisting (6FBT) technology enables the integral forming of square tube components with complex shapes. However, the process analysis method and the deformation behavior of square tube spiral components in the bending and twisting process have not been investigated. In this paper, an analytical model of the bending die trajectory suitable for one-time forming of square tube spiral components is proposed and verified by FE simulations and experiments. In this model, the bending direction of the component axis is changed continuously by adding an additional cross section torsion angle in the bending process of the square tube, and then the spiral member is formed. This paper further reveals the laws of stress, strain, wall thickness distribution and cross section distortion of 304 stainless steel square tube spiral components in the 6FBT process. The results show that during the forming process, the equivalent stress on the edge of the square tube is greater than that on the surface, the wall thickness reduction on each cross section only occurs on the outside of the bent, and the section distortion between the inside and outside of the bent is larger than that between the inside and outside of the twist.

六轴自由弯曲和扭转（6FBT）技术可以实现复杂形状的方管部件的整体成型。然而，尚未对方管螺旋构件在弯扭过程中的工艺分析方法和变形行为进行研究。本文提出了一种适用于方管螺旋部件一次性成型的折弯模具轨迹分析模型，并通过有限元仿真和实验进行了验证。在该模型中，通过在方管弯曲过程中增加额外的截面扭转角，不断改变构件轴的弯曲方向，从而形成螺旋构件。本文进一步揭示了应力、应变、304不锈钢方管螺旋构件在6FBT工艺中的壁厚分布和截面畸变[J]. 结果表明，在成形过程中，方管边缘处的等效应力大于表面处的等效应力，各截面的壁厚减小仅发生在弯头外侧，且方管之间的截面变形内弯和外弯大于内弯和外弯之间的弯。