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A preparation method of a large-diameter special-shaped thin-walled tubular molybdenum-based alloy part

A molybdenum-based alloy, large-diameter technology, applied in the field of powder metallurgy, can solve the problems of uneven forging deformation, cracking of the bar, poor uniformity of the structure and properties of the bar, etc., to achieve uniform structure distribution, inhibit grain growth and shortening. Effect of sintering time

Active Publication Date: 2020-03-24
NO 59 RES INST OF CHINA ORDNANCE IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method is usually only suitable for the preparation of molybdenum-based alloy rods with a diameter of less than 100mm. If the diameter is larger, this process is difficult to achieve forging and toughening of the central part of the rod, and the uniformity of the structure and properties of the rod is poor.
For example, for large-diameter (outer diameter ≥ 100mm) special-shaped (the special-shaped here refers to the thicker wall thickness in the middle of the tube and thinner wall thickness at both ends) thin-walled (wall thickness range is generally 4 ~ 10mm) tubular molybdenum-based alloy Parts, if the above method is adopted, due to the high content of hard and brittle phase oxides, carbides and other particles in the molybdenum-based alloy, during the large deformation and toughening forging process of the billet, forging defects such as cracking and delamination of the billet are prone to occur. Moreover, the diameter of the sintered molybdenum-based alloy billet is large, and the uneven forging deformation will easily lead to extremely uneven structure and performance of each part of the billet, resulting in low room temperature and high temperature strength and toughness of the molybdenum-based alloy parts, which are far from meeting the requirements of high temperature and high temperature. Requirements for service in special environments such as overload shock and high-frequency vibration

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  • A preparation method of a large-diameter special-shaped thin-walled tubular molybdenum-based alloy part
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  • A preparation method of a large-diameter special-shaped thin-walled tubular molybdenum-based alloy part

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Embodiment 1

[0056] A method for preparing a special-shaped thin-walled tubular molybdenum-based alloy part with an outer diameter of 100mm and a maximum wall thickness of 5mm, comprising the following steps in sequence:

[0057] (1) Material selection

[0058] Molybdenum dioxide powder, rare earth lanthanum nitrate and TiC carbide powder are selected as raw materials; among them, the dosage ratio of molybdenum dioxide powder, rare earth lanthanum nitrate and TiC carbide powder is calculated according to mass percentage, and rare earth lanthanum nitrate: 0.5% , TiC carbide powder: 2.5%, the rest is molybdenum dioxide powder;

[0059] (2) Powder pretreatment

[0060] According to the mass percentage content of each raw material, the rare earth lanthanum nitrate solution is prepared first, and then the rare earth lanthanum nitrate solution is evenly doped in the molybdenum dioxide powder by liquid spraying, and the primary powder is obtained after vacuum drying. Preparation of Mo-La by Hig...

Embodiment 2

[0077] A method for preparing a special-shaped thin-walled tubular molybdenum-based alloy part with an outer diameter of 135mm and a maximum wall thickness of 7mm, comprising the following steps in sequence:

[0078] (1) Material selection

[0079] Molybdenum dioxide powder, rare earth lanthanum nitrate and TiC carbide powder are selected as raw materials; among them, the dosage ratio of molybdenum dioxide powder, rare earth lanthanum nitrate and TiC carbide powder is calculated according to mass percentage, and rare earth lanthanum nitrate: 1.5% , TiC carbide powder: 1.0%, the rest is molybdenum dioxide powder;

[0080] (2) Powder pretreatment

[0081] According to the mass percentage content of each raw material, the rare earth lanthanum nitrate solution is prepared first, and then the rare earth lanthanum nitrate solution is evenly doped in the molybdenum dioxide powder by liquid spraying, and the primary powder is obtained after vacuum drying. Preparation of Mo-La by Hig...

Embodiment 3

[0098] A method for preparing a special-shaped thin-walled tubular molybdenum-based alloy part with an outer diameter of 160 mm and a maximum wall thickness of 8 mm, comprising the following steps in sequence:

[0099] (1) Material selection

[0100] Molybdenum dioxide powder, rare earth lanthanum nitrate and TiC carbide powder are selected as raw materials; among them, the dosage ratio of molybdenum dioxide powder, rare earth lanthanum nitrate and TiC carbide powder is calculated according to mass percentage, and rare earth lanthanum nitrate: 3.0% , TiC carbide powder: 0.5%, the rest is molybdenum dioxide powder;

[0101] (2) Powder pretreatment

[0102] According to the mass percentage content of each raw material, the rare earth lanthanum nitrate solution is prepared first, and then the rare earth lanthanum nitrate solution is evenly doped in the molybdenum dioxide powder by liquid spraying, and the primary powder is obtained after vacuum drying. Preparation of Mo-La by H...

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Abstract

The invention relates to a method for preparing a large-diameter special-shaped thin-walled tubular molybdenum-based alloy part, which is characterized in that it includes the following steps in sequence: (1) material selection; (2) powder pretreatment; (3) prefabricated green body forming; ( 4) Pre-sintering; (5) Hot isostatic pressing densification; (6) Spinning; (7) Overall heat treatment and other steps. The large-diameter special-shaped thin-walled tubular molybdenum-based alloy parts prepared by the preparation method have many advantages such as excellent room-temperature mechanical properties and high-temperature mechanical properties.

Description

technical field [0001] The invention belongs to the technical field of powder metallurgy, and in particular relates to a method for preparing a large-diameter special-shaped thin-wall tubular molybdenum-based alloy part. Background technique [0002] Molybdenum and molybdenum alloy materials have high melting point (above 2600 ℃), moderate density (10g / cm 3 ), strong toughness and other advantages, it is suitable for high temperature erosion and ablation above 1600 ℃, overload impact above 500g, 5×10 6 An ideal structural material for service in special environments such as the above high-frequency vibrations. Based on the alloy strengthening and toughening mechanism, adding La to metal molybdenum 2 o 3 Rare earth oxide particles such as rare earth oxide particles and carbide particles such as high melting point TiC can not only significantly improve the room temperature mechanical properties such as the flexural strength of the alloy, but also greatly improve the high te...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F1/00C22C27/04C22C1/05C22C1/10B22F3/04B22F3/10B22F3/15B22F3/14B22F3/24B22F5/10
CPCB22F1/0003B22F3/04B22F3/1017B22F3/14B22F3/15B22F3/24B22F5/106B22F2003/248B22F2998/10B22F2999/00C22C1/05C22C27/04B22F2201/013
Inventor 陈大军李忠盛吴护林张隆平丛大龙宋凯强陈汉宾
Owner NO 59 RES INST OF CHINA ORDNANCE IND