Comparison Of The Performance Of Brake Material For Drilling Rig Based Sintered By Cold And Hot Pressing Method

With the depletion of shallow mineral resources,geological prospecting has been going from shallow to deep.Under the condition of deep hole drilling,the weight of drill pipe and the drilling will be greatly increased during operation,In order to ensure the drilling efficiency and the safety of construction personnel,the requirement of the deep hole drilling hoist brake materials has been highly improved.With a high and stable friction coefficient,high temperature and high pressure resistance,wear resistance material is very suitable for using as the brake material of deep hole drilling hosit.The sintering methods of powder metallurgy brake pads can be divided into two types,namely cold sintering method and hot sintering method.The biggest difference between these two sintering methods is whether the powder is subjected to high pressure(generally above 200 MPa)before sintering.In order to make a comparison on the advantages and disadvantages of these two methods,the brake pads were sintere by cold and hot sintering methods in this paper,the properties of each brake pads were tested as well.Firstly,this paper determines the manufacturing process of cold and hot-pressing sintered brake pads,and studies the effect of pressing pressure on the performance of cold-pressed brake pads.A comparative study on the performance of four cold pressed brake pads under the pressure of 250 MPa,300MPa,450 MPa and 600 MPa showed that the performance of cold pressed brake pads under the pressure of 300 MPa to 450 MPa is better.Secondly,this paper sintered two brake pads within the optimum pressure(300 MPa)by cold sintering method and two by hot sintering method at the same time.Andthe physical and mechanical properties,friction and wear properties and micro-morphology of these coldpressed and hopressed brake pads were tested and observed.Through the comparative study test results of the performance of coldpressed and hotpressed brake pads,this paper concludes as follows:(1)The hardness and friction coefficient of cold pressing sintered brake pads are similar to those of hot pressed sintered brake pads;(2)The performance of the cold pressing sintered brake pads is better than that of hot pressing sintered brake pads in density,compressive strength and strength and stability of friction coefficient;(3)The wear extent of hot pressing sintered brake pads is less than that of cold pressing sintered brake pads in high speed.The final conclusion is that the performance of cold pressing sintered brake pads is similar to that of CRCC(China Railway inspection and Certification Center),the cold pressing sintering method is more suitable for the manufacture of heavy-duty brake pads.The sintering parameters are as follows: cold pressing pressure of 300 MPa,sintering pressure of 3Mpa,sintering temperature of 950?,heating rate of 50?/min,holding time of 5 minutes.