The Study Of Cladding Extrusion Technology Of The Wear Resistant Cast Iron Cr26

This paper takes the high chromium cast iron Cr26 as the research object which hold the brittle and wear-resistant properties, the material of 16 Mn as inner and outer cladding layer, Cr26 as intermediate wear layer. Completed the extrusion of Cr26 high chromium cast iron material by coating extrusion methods. We have determined the extrusion plant conditions through high temperature compression test and extrusion workshop test. The extruded tubes testing to determine the feasibility of cladding extrusion processing, and produce in line with the actual application of 16Mn/Cr26 type double-metal composite tube. 16 Mn of multiple tube outer plays a role of tenacity, inner Cr26 is wear-resisting layer. Through differential thermal analysis method to determine the austenitizing temperature Cr26 high chromium cast iron, the heat treatment process was studied to improve the comprehensive performance of composite pipes. Conclusions are as follows:(1) By controlling the pouring temperature and pouring time and casting speed, to achieve a three-metal wear tube 16Mn/Cr26/16 Mn cast molding, the composite interface combined with high strength, there are without interface slag and stratification or other defects. Three-metal tube casting process affected by centrifugal force and temperature, tube composition changes, and the emergence of carbon segregation led to a peak value of hardness.(2) Through the high-temperature compression test, we know that when the temperature is higher than 1100 ℃ Cr26 deformation resistance becomes rapid reduce, the degree of reduce changes slowly when the temperature continus to rise, when the temperature is close to 1250 ℃, partial becomes melting, tube extrusion temperature is determined for 1100~1150 ℃, the extrusion speed appropriate smaller.(3) Coated extrusion composite seamless tube adopts glass powder lubrication, annular furnace heating, heating time about 2.5~3 h, After high-pressure descaling the first induction heating temperature is 1090~1100 ℃, the second induction heating temperature is 1120~1140 ℃. Low temperature glass powder, poor lubrication. Cr26 easy to break when the temperature of extrusion is too high. the shear stress of metal in groove can reduce and increase the flow stability through a way that in a suitable temperature range extrusion is moderate, extrusion speed was lower than those of nickel-based alloy slightly.(4) By detecting the composite pipe extrusion products, the wear-resisting pipe group is even refined than before, the hardness of Cr26 reach more than 56 HRC, conform to the requirements of the standard. Results of impact test shows that the composite pipe is similar to single metal 16 Mn impact curve shape, both have good resilience, after 1020 ℃ heating and cooling treatment molding pipe not happen craze, grassroots 16 Mn has good tenacity, the pipes play not easily burst.(5) The DTA image display that Cr26 high chromium cast iron minimum phase change at 809 ℃, during the process of wear are mainly abrasive wear and tear. We can got the excellent properties of extrusion tubes, when these tubes after different heat treatment and in the 1050 ℃ heat preservation 60 minutes and empty cold, which hardness up to 64.2 HRC, and wear resistance is the best.