Study On Powder Metallurgy Brake Shoe For Deep Hole Drill

With the development of modern society, geological drilling is moving towards deep and super-deep direction. With the increase of wells depth and self-weight of drilling pipe, brake materials is needed to provide greater braking torque. When the emergency happens, the deeper the well is, the more braking torque is needed, and the friction materials should have good heat resistance and thermal conductivity which prevents damage or failture of frction materials. Meanwhile, due to the high frequency of braking during hoisting or descending drill pipe, the friction materials should have good abrasion resistance.This paper based on the mechanism of friction and wear analyzes the factors which could effect the friction factor and wear performace of powder metallurgy friction materials. This research concludes the components of iron-based and copper-based friction materials and finds the roles of various component which gives the basis of resonable scope of formula selection.Combined with practical application, the research designed the steel back structure of metallurgical powder brake block and the brake block friction layer, and it also designed moulds according to the corresponding structure. The brake block structure consists of steel back and friction material, and the latter can be divided into transition layer and working lining. This structure is good for independent prodcution of steel back, improving the production efficiency. Adding transition layer materials could enhance the adhesion between steel back and friction materials, avoid the separation or off between steel back and friction materials due to the change of temperature and load in the friction.The brake block production process adopts the process engineering of prepararing, mixing and loading of powder, producing steel back, and sintering with hot-presse approach. Based on formula 1, through the contrast tests, it studied the influence factors of brake performance. The scope of process parameter that suits the formula is obtained as follows: sintering temperature range is 850~950℃, sintering pressure is 12 ~ 20MPa,and holding time is 10 ~ 20 min. In addition, how to produce more excellent performance of brake block process is concluded.