The invention relates to a preparation method of Ti-Mo-Ni alloy ingot
Titanium and titanium alloys have high specific strength and corrosion resistance, which is a promising structural material and corrosion resistance material. Since the early 1950s, industrial scale production has been limited to the military aviation industry due to price and supply problems. With the development of titanium industry, titanium and titanium alloy gradually from military to civil, from aviation industry gradually to general industry, the most important is to do corrosion resistant structural materials. At present, the world's general industrial titanium volume is increasing, corrosion resistant titanium alloy in petrochemical industry, alkali industry, electroplating and electrolysis industry, chemical industry, metallurgy industry, pharmaceutical industry and thermal power generation, seawater desalination, medical and health industries and other applications are increasing, with broad prospects for development. The research of corrosion resistant titanium alloy can be traced back to the end of the 1940s, that is, in the early stage of titanium development, the development of corrosion resistant titanium alloy has begun. With the deepening of corrosion resistant titanium alloy research, the corrosion resistant titanium alloy has been successfully applied titanium palladium alloy, titanium molybdenum alloy, titanium tantalum alloy, etc., among which titanium molybdenum nickel titanium alloy is the most commonly used corrosion resistant titanium alloy, its high temperature, low RA value chloride or weak reducing acid has good crack corrosion resistance. Its corrosion resistance is significantly better than pure titanium and close to Ti-O. 2Pd alloy.
Titanium-molybdenum-nickel alloy contains refractory metals molybdenum and nickel. The melting point of molybdenum is 2615t: and the density of molybdenum is 10.2g /cm, which are 1.57 and 2.27 times of that of titanium respectively. Although the melting point of nickel is only 1455t:, its density is 8. 9g/cm3, twice that of titanium. Conventional titanium molybdenum nickel ingot smelting production method is to add pure molybdenum and pure nickel, or add Ti -mo intermediate alloy and pure nickel, but due to the high melting point, density and molybdenum nickel density is big, in the consumption of smelting process of molybdenum or molybdenum additives without fully melted away into the molten pool of quality hidden trouble, because the vacuum consumable smelting has the intrinsic characteristics of the molten pool over low heat, The short maintenance time of liquid molten pool can not effectively remove high and low density inclusions, resulting in the insufficient alloying of unmelted molybdenum and nickel with titanium elements in the matrix, so it is difficult to obtain the ingot with uniform composition. The ingot produced has a small area of uneven molybdenum or nickel composition, which ultimately affects the corrosion resistance of Ti-O-3Mo-0.8Ni titanium alloy. Therefore, the original ti-Mo-Ni ingot production process has the following shortcomings: 1) pure metal addition, there are high density inclusion quality hazards; Ti-mo intermediate alloy and pure nickel addition, because of the particularity of ti-Mo intermediate alloy production process, its production cost is high; In addition, the composition of the two processes is not uniform, which affects the metallurgical quality of titanium. 2) It cannot meet the corrosion resistance requirements of titanium materials in metallurgy, petrochemical and other special industries; 3) Ingot containing metallurgical defects are easy to crack and produce microcracks in post-sequence processing, affecting the yield of material. Meanwhile, small cracks cannot be completely found through non-destructive testing and other technologies. Fatigue failure, fracture, leakage and other accidents will be caused at the microcracks in the use of titanium materials, resulting in great economic losses. Therefore, it is necessary to develop a reliable smelting technology to eliminate the above defects and produce high quality titanium alloy ingot with uniform distribution of molybdenum and nickel without segregation and inclusion of metallurgical defects.
