Tianjin Huayuan Metal Wire Products Co.Ltd
Address: Zhangjiafangzi, Tuanbo Town, Jinghai County, Tianjin City, China
Tel: +86-22-68509690 68509822
In the drawing process, the drawing stress of the drawing force applied to the drawing area of the unit cross section of the drawn wire at the drawing mouth is drawn to the pull 1. In order for the metal to undergo plastic deformation in the mold hole, the tensile stress of strain 1 must be greater than the deformation resistance of the metal in the deformation area of the mold hole. In order to prevent the drawing process in which the deformation of the wire after it is drawn out of the die hole continues to be drawn or broken, and thus destabilizing the drawing process, the drawing stress value of 1 must be less than the yield limit of the drawn wire after the die hole is drawn. Therefore, the condition for realizing the drawing process is usually expressed as follows: v T< v v 1< v v s. The ratio K is called the safety factor of the drawing process.
After experiencing the cold drawn metal wire, it produces obvious deformation and hardening. Its yield limit, s value, is close to its strength limit, v, which is commonly used in production to replace v, so the condition of the drawing process can also be expressed as unv T< v 1< v s. The safety factor K of the drawing process can also be expressed by the ratio of net b to net 1.
The K value of the safety factor in the drawing process is generally between 1.40 and 2.0. K<1.40 means that the tension at the drawing stress is too high. The metal wire may continue to deform after the die hole, and the drawing process is unstable. >2.0 indicates that tension strain 1 is small, deformation is too small in the second drawing, and the second drawing is increased. In the case of ultra-fine metal wire whose drawing diameter is less than 0.05mm, it is difficult to wear the die. In order to improve the stability of drawing process, reduce The Times of pulling and breaking, and improve the drawing production efficiency, the safety factor K value can be used to be greater than 2.0.