Research On Longevity Arc Deposition Process And Equipment Of Blast Furnace Tuyere

As one of the key components of the blast furnace, tuyere directly affects the stable operation of the blast furnace, the production efficiency and the production costs for the useful life with its main function of blowing coal towards blast furnace. Under the working environment inside blast furnace cylinder at above 2000 ?, the front-end of tuyere is located at the corrosion and erosion of melted iron chronically with the main failure mode for ablation. Besides, under the high-speed erosion of hot air and pulverized coal of 1200 ? for the inner wall, while under the strong oxidation for burning circulation area simultaneously, its main failure mode is wear. Therefore, it is necessary to hardening the inner and outer surfaces of the side for the tuyere.Currently, the following two majors are adopted by the domestic and international. The first is the use of a plasma thermal spraying method. However, it only forms a mechanical bond for the thermal spray method and the substrate with the small layer thickness and high porosity easily to wear off. The second is the use of welding methods which could achieve the thick layer of welding and form the metallurgical bonding when combined with furnace tuyere. The current welding materials are nickel-copper alloys with low wear resistant and high temperature oxidation resistance.Aiming at the actual use of blast furnace and the main failure mode in production, the study puts forward the methods of adopting the surfacing high temperature resistant alloy in the inner wall outlet by arc deposition process and plasma spraying process of high-temperature ceramic materials in the outlet wall. By proposing the material of the transition layer as JSTNi6382 and the surface as D450, the study will analyze the microstructure, micro-hardness, wear resistance and thermal shock resistance of the cladding layer.The micro-hardness was measured along the deposition direction of strengthening equidistant samples with the test results showing that the sample micro-hardness direction along deposition increased gradient hardness gently as the hardness of thecopper substrate for 46 HV, the micro-hardness of transition layer JSTNi6382 for about200 HV, the surface D450 for 360HV(35HRC) and he surface D600 for 480HV(47HRC).The wear tests show that the wear resistance of D450 is 5.8 times to copper and D600 is17 times to copper at room temperature. Experimental results show that the macroscopic crack appeared after 6 times' thermal shock for D600, but did not appeared after 10times' thermal shock for D450, and the thermal shock resistance of the sample by HDMR process is far superior to plasma spraying. Therefore, the study will reinforce the inner wall outlet of blast furnace tuyere by considering the method of cladding with JSTNi6382 as transition layer and D450 as surface.