Abstract：The finite element（FE）method is used to simulate the deformation courses of three different deformation processes for the small-sized UNS N08825 inconel seamless steel tube，based on which，relevant elements associated with the cold-drawing process are analyzed，including distributions of the stress，the strain and the metal flow speed， and the changes of wall thickness before and after the cold-drawing process，and the cold drawing load is predicted. Combined the simulation result with the site production experience，the most suitable deformation process path is determined. Key words：seamless steel tube；cold-drawing；inconel；UNS N08825

UNS N08825 is a nickel-iron – chromium – based nickel alloy. In addition to Cr and Ni, it also contains alloying elements such as Mo, Cu, and Ti.

This alloy has an austenitic structure when subjected to hot working at 1150 – 1230 °C. At room temperature, its reduction of area can reach over 50%. It exhibits good corrosion resistance in both reducing and oxidizing media, and possesses excellent hot – and cold – working properties as well as low – temperature mechanical properties. It shows good corrosion resistance in flowing seawater, and has good resistance to various waste gases, alkaline solutions, and most organic acids and their compounds. It is commonly used in the form of pipes in important engineering fields such as petrochemical industry and heat exchangers.

Pipe forming is an important link in production and application. Usually, hot extrusion or hot piercing methods are used for billet preparation, and then cold rolling or cold drawing methods are used for diameter and wall thickness reduction until the target size is achieved. Among the cold deformation processes, the cold drawing process is more flexible compared with cold rolling. It can flexibly reduce the diameter of steel pipes and achieve the desired mechanical properties. Only the outer die needs to be replaced when changing specifications, so it has been widely used in actual production.

In the cold drawing process, deformation control is the key. Improper design of the deformation amount may lead to a mismatch between the tonnage of the drawing machine and the actual drawing force, resulting in problems such as the breakage of the drawing head. Therefore, it is very important to rationally match the material properties and the deformation amount. The finite element simulation analysis method is a modern and intelligent analysis method that has been widely used in the manufacturing field. Simulation analysis can be used to estimate the cold drawing load, the stress concentration during the cold drawing process, and the size changes. It has important guiding significance for the production practice of pipes and can also greatly reduce the cost of process optimization.