Study On Manufacturing Process And Mechanical Property Of Modified High Manganese Wear-resistant Steel Ring-hammer

Ring-hammers are the mainly key and worn parts of crackers, which service life and the production cost are directly affected by the wear resistance of the component. According to the working condition of ring-hammer, a modified high manganese wear-resistant ring-hammer (MHMWRRH) material and new molding technology of iron-sand molding & spiral-ring chill lost foam casting, the main researching contents and results are as follows:The components of MHMWRRH were designed, based on the high manganese steel and with an addition of rare earth and tieshen No.1 complex modification. The mainly chemical component is about C:0.9～1.2,Mn:11.0～14.0,Si:0.3～0.7,Cr:0.1～0.5,Mo:≤0.3,V≤0.1,Ti≤0.1,P,S≤0.04,RE: 0.1～0.3%, tieshen No.1:0.3～0.6%. The typical microstructure is composed of austenite and sliced carbide.The wear mechanism of MHMWRRH was studied under different working conditions. Results show that the optimized chemical composition of MHMWRRH is related to the wear failure modes. When worked in conditions of heavy loading and high contact stress, the mainly failure form of the ring-hammer is fatigue wear and sliding wear MHMWRRH with fine austenite and appropriate hardness, strength and ductility should be chosen to improve its the mechanical property and service life.The sand casting and spiral-ring chill lost foam casting molding method was put forward for the first time and used for the production of MHMWRRH. The results show that when cast by the iron-sand, it not only has the inherent characteristic of sand molding but also act a function of metallic types. The casting cooled quickly in the molds, the crystal grains are refined, and the density is also improved. At the same time, the cooling capacity of spiral-ring chill is compensated; the phenomenon as adhering sand in the inner circle of ring, cracking and coursing of the crystal grain is effectively suppressed.According to the characteristics of MHMWRRH lost foam casting, a new method of the mixed bottom and top coating is successfully employed. Production practice shows that with this compound coating, the impacting action of heat burst to cavity was greatly weakened, the heat stress was reduced and cracking was also effectively prevented.The practice experiences verified that the properties of MHMWRRH produced with the modification technique are as follows:σb=724MPa,αk=219J/cm2,δ=37%,HB=210, the yield>95%. After water toughening at 1080oC for 3h, the properties can meet the requirements of application. The products developed in this paper have a better wear-resistant property, the production efficiency has been greatly improved and the cost is decreased, which will have an obvious market competition prospect.