Extrusion machine reamer is the key to the concrete extrusion machine parts, its material is metamorphic iron. As-cast organization of austenite + eutectic carbide (M, C, type), mechanical performance is: a = 940 mpa, hardness is 54 HRC, aK = 5.4 J/cm. Reamer work in the whole extrusion press forward in the processes of concrete floor plate forming operation. Imported bearing the workpiece under extrusion, impact stress in the work, and use the impact from corrosion, imported bearing the workpiece high hardness (HRC 62 or higher) and high bending strength (- > 600 mpa), good impact toughness (j/cm. 7 or higher) , and should have good corrosion resistance; Also asked that the workpiece deformation small, parallel to the axis of good; In addition in reamer has excellent abrasion resistance (> 10000 m) operation, artifact damage rate (a split, broken, etc.) should be less than l %. According to the request of reamer working, different requirements at different positions of the workpiece hardness, and its strict deformation. In the production practice shows that the heat treatment to prevent oxidation decarburization and reduce the quenching deformation is the key of the reamer heat treatment quality.
Found in imported Bearings Distributor h t t p:/ /w w w.fagbearings-hk.c o m/ , the improper heat treatment technology and operational negligence, make the reamer oxidation decarburization or deformation is too large, easily cause failure scrapped. To prevent reamer oxidation decarburization and heat treatment requirements of the different parts of the different hardness of workpiece, and get Ngg /], requirements, such as using local quenching tempering technology limited, control different hardness both deformation control is difficult. If use local coating to protect overall quenching tempering again, on the one hand, different hardness can be obtained in different parts of the workpiece, the second to prevent oxidation decarburization of workpiece and reduce the deformation. Test process in the thin wall cladding coating and the corner, can make each part of the workpiece heating and cooling rate tends to be uniform, so as to prevent deformation and cracking of workpiece defects. To this end, the reamer thread section of coating paint protection) to improve overall quenching tempering process test, test result is good, process characteristics are as follows:
2 (1) coating in cafe a 4 mm aluminium silicate fiber and 74-104 - m hollow glass beads as the basic material, match with sodium silicate + + dextrin pulp.
(2) the coating method. Threaded parts coated about 5 mm aluminum silicate fiber coating. To reduce the hardness of the transition zone, reduce the length of transition zone, designed a head screw, the size of 100 ram x 20 mm, in addition, the reamer ~ 50 mm cone hole injection binder, and fill the hollow glass bead, thread surface to prevent oxidation, before the above process can apply a layer of anti oxidation coating and then to the process.
(3) the imported bearing heat treatment process. Annealing processing first, make the threaded parts hardness less than 38 HRC; 960 ℃ and then quenching treatment, the overall workpiece x 2 h after heating air cooling quenching, subsequent 250 ~ C x 4 h tempering treatment. Reamer with the improved process, after the workpiece quality, its hardness and mechanical properties are shown in table 17 _7 and table 17-8. In addition, due to containing rare earth elements in the metamorphic iron, workpiece excellent corrosion resistance; Workpiece axis deviation range for. 5. 1.2 NLNL, conform to the technical requirements, to meet the requirements of assembly in production, the production well.