Preparation method of composite rare earth oxide reinforced molybdenum alloy piercing mandrel

Abstract

The invention discloses a preparation method of a composite rare earth oxide reinforced molybdenum alloy piercing mandrel. The method includes the steps: firstly, uniformly mixing carbon powder, titanium hydride powder, zirconium hydride powder and rare earth oxide powder in a three-dimensional mixer to obtain doped powder, and then uniformly mixing the doped powder and molybdenum powder to obtain mixed powder raw materials; secondly, pressing the mixed powder raw materials to form piercing mandrel blanks; thirdly, finishing the piercing mandrel blanks to remove redundant piercing mandrel blanks; fourthly, sintering the finished piercing mandrel blanks, and cooling the sintered the piercing mandrel blanks to reach indoor temperature to obtain the composite rare earth oxide reinforced molybdenum alloy piercing mandrel. Composite rare earth oxide is added based on a TZM (titanium zirconium molybdenum) alloy, and the molybdenum alloy piercing mandrel with fine high-temperature hardness and flexural toughness is prepared by the aid of technological processes such as mixing, pressing, finishing and sintering and can stably adapt to high-temperature, high-pressure, splat cooling and quick heating working environments.

Description

technical field [0001] The invention belongs to the technical field of molybdenum alloy plug preparation, and in particular relates to a method for preparing a molybdenum alloy plug strengthened by composite rare earth oxides. Background technique [0002] During the piercing process of the seamless steel pipe, the molybdenum alloy plug is in direct contact with the high-temperature steel billet. Under the action of rolling friction, the temperature of the nose of the molybdenum alloy plug is as high as 1300°C, and the entire cone area of ​​the molybdenum alloy plug bears this huge pressure. Axial pressure, radial stress and surface friction. At the same time, the molybdenum alloy plug must be forced to cool in water during the process of pipe penetration. In such a harsh working environment of high temperature, high pressure and rapid cooling and rapid heating, molybdenum alloy plugs are subjected to the combined effects of mechanical fatigue and thermal fatigue, and are pr...

AI Technical Summary

Problems solved by technology

In such a harsh working environment of high temperature, high pressure and rapid cooling and rapid heating, molybdenum alloy plugs are subjected to the combined effects of mechanical fatigue and thermal fatigue, and are prone to failure forms such as collapse, thick pier, sticking steel, and cracking, resulting in the use of plugs. The service life is reduced, which seriously affects the forming quality, production cost and efficiency of the steel pipe

[0003] In order to solve the above problems, the conventional method uses TZM alloy (zirconium-titanium-molybdenum alloy) to prepare the plug. The mechanism of action is to form a small amount of carbide elements in solid solution in the molybdenum matrix, thereby increasing the recrystallization temperature and strength of the molybdenum alloy. However, the molybdenum alloy plug The working environment is extremely harsh, and the molybdenum base itself is a brittle material. The TZM alloy plug has the defect of being easy to crack or even break under the huge torque of the rolling rod.

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