Brake drum is an important component of automobile drum brake and one of the main security parts of automobile. It plays an important role in driving safety. The development direction of automobile lightweight requires that the brake drum should also be lightweight, so as to reduce the vehicle weight and save resources, and meet the development concept and requirements of green manufacturing. However, this puts forward higher requirements for the performance of brake drum materials and the design of brake drum, which makes the development of high-performance gray cast iron brake drum inevitable and very urgent. Because gray cast iron has good thermal conductivity, shock absorption, wear resistance, excellent casting performance and low manufacturing cost, almost all brake drums of motor vehicles are made of gray cast iron, the main brands are HT200 and HT250.
(1) The graphite morphology of vanadium titanium gray cast iron is mainly A-type graphite and D-type graphite. With the increase of vanadium and titanium content, the graphite structure is refined and promotes the transformation from graphite to D-type graphite; The content of carbon silicon, vanadium and titanium increases further, and coarse thick flake or massive graphite will appear.
(2) The strength and hardness of gray cast iron increase with the increase of vanadium and titanium content; When the content of carbon, silicon, vanadium and titanium increases further, its strength and hardness decrease significantly.
(3) With the increase of vanadium and titanium content, its thermal conductivity decreases; With the further increase of carbon vanadium titanium content, its thermal conductivity increases obviously.
Compared with ordinary gray cast iron, vanadium titanium gray cast iron has higher strength and better wear resistance. It is suitable for preparing automobile brake drum. What is more advantageous is that Panzhihua is rich in vanadium and titanium resources, and the gray cast iron produced with local raw materials contains alloying elements such as V and Ti, so the performance of vanadium and titanium gray cast iron is better; Moreover, the natural introduction of V and Ti elements will not increase the additional cost. However, if the content of V and Ti in gray cast iron is too high, it will deteriorate the microstructure and properties. Therefore, the control of Ti and V in vanadium titanium gray cast iron is very key, and the microstructure and properties of vanadium titanium gray cast iron brake drum need to be further optimized. In this paper, the author studies and analyzes the changes of microstructure and properties of V-Ti gray cast iron brake drum with different components, and explores the best component ratio scheme.