阅读说明：本技术 Co-Cr-Mo-N合金及其制备方法 (Co-Cr-Mo-N alloy and preparation method thereof ) 是由 陈业高 邵国友 彭伟平 彭剑凌 丹斌 于 2020-05-21 设计创作，主要内容包括：本发明涉及材料加工领域,公开了一种Co-Cr-Mo-N合金的制备方法,包括以下步骤：真空熔炼-真空浇铸-热处理-轧制-切割。将Co-Cr-Mo-N合金真空熔炼浇铸后,加热至1150~1350℃,星型轧制,单次轧制量10%~18%,终轧直径8~10mm。本发明使用轧制的方法对Co-Cr-Mo-N合金进行加工成形为细杆,不仅加工工艺简单,有效提高了加工效率,而且制品组织细化,粗大相破碎,致密度提高,提升了材料的力学性能。(The invention relates to the field of material processing, and discloses a preparation method of a Co-Cr-Mo-N alloy, which comprises the following steps: vacuum melting, vacuum casting, heat treatment, rolling and cutting. After the Co-Cr-Mo-N alloy is subjected to vacuum melting and casting, heating to 1150-1350 ℃, performing star rolling, wherein the single rolling amount is 10% -18%, and the final rolling diameter is 8-10 mm. According to the invention, the Co-Cr-Mo-N alloy is processed and formed into the thin rod by using a rolling method, so that the processing technology is simple, the processing efficiency is effectively improved, the product structure is refined, the coarse phase is crushed, the compactness is improved, and the mechanical property of the material is improved.)

1. A preparation method of a Co-Cr-Mo-N alloy is characterized by comprising the following steps:

vacuum smelting: vacuum degree is less than or equal to 10^-2Pa, the smelting temperature is 1550-1680 ℃; pretreating Co, Cr and Mo single components or their binary or their ternary alloy, adding them into crucible, vacuumizing until the vacuum degree is less than or equal to 10^-2Pa; heating to melt, controlling the temperature to be 1620-1680 ℃, and keeping the temperature for 1-3 h;regulating and controlling the components to ensure that the components of other elements except the N element are reasonable; adding N, and performing electromagnetic stirring to meet the requirements of components and uniformity; preserving the heat for 0.5-1 h, detecting the components, and regulating and controlling the components to be qualified;

vacuum casting: cooling the melt to 1480-1520 ℃, preserving the temperature for 0.1-0.5 h, and then casting the melt into a bar with the length of 50-2000 mm and the diameter of 30-80 mm in a vacuum casting chamber; transferring the bar material to a heat treatment furnace when the temperature of the bar material is reduced to below 1200 ℃;

and (3) heat treatment: controlling the furnace temperature at 1050-1250 ℃, keeping the temperature for 3-20 h, and discharging and air cooling; heating the cooled bar to 300-550 ℃, preserving heat for 1-20 h, then rapidly heating to 1150-1350 ℃, and preserving heat for 0.2-1 h;

rolling: star-shaped rolling is carried out on the bar material at a high temperature, the single-time rolling amount is 10-18%, and the final rolling diameter is 8-10 mm;

cutting: cutting according to the requirement, wherein the length is 20-50 mm.

2. The method for producing a Co-Cr-Mo-N alloy according to claim 1, wherein in the rolling step, a roller normal angle of the star rolling is 90 ° or 120 °, and a rolling speed is 1 to 10 m/min.

3. The method of producing a Co-Cr-Mo-N alloy according to claim 1, wherein in the melting step, N is added by a method of adding a nitride.

4. The method of claim 3, wherein the nitride is chromium nitride.

5. The method for preparing the Co-Cr-Mo-N alloy according to claim 1, wherein in the smelting step, N is added by introducing nitrogen at 1320-1480 ℃ and keeping the temperature for 1-3 h.

6. The method of producing a Co-Cr-Mo-N alloy according to any one of claims 1 to 5, wherein in the vacuum melting step, the binary alloy raw material of cobalt, chromium, and molybdenum is a cobalt-chromium alloy or a cobalt-molybdenum alloy.

7. The method of producing a Co-Cr-Mo-N alloy according to any one of claims 1 to 5, wherein in the vacuum melting step, the ternary alloy raw material of cobalt, chromium, and molybdenum is a cobalt-chromium-molybdenum alloy.

8. The method of producing a Co-Cr-Mo-N alloy according to any one of claims 1 to 5, wherein in the vacuum melting step, the method of pretreatment is any one or a combination of:

drying, cleaning, degreasing and crushing.

9. A Co-Cr-Mo-N alloy, characterized by being produced by the production method according to any one of claims 1 to 4.

10. The Co-Cr-Mo-N alloy of claim 9, consisting of the following components in weight percent: 27-30% of Cr, 5-7% of Mo, 0.1-0.5% of N, 0.2-0.35% of C, less than or equal to 1% of Mn, less than or equal to 1% of Si, less than or equal to 0.5% of Ni, less than or equal to 0.75% of Fe, less than or equal to 0.2% of W, less than or equal to 0.02% of P, less than or equal to 0.01% of S, less than or equal to 0.03% of Al, less than or equal to 0.1% of Ti.

Technical Field

The invention relates to the field of metallurgy, in particular to a Co-Cr-Mo-N alloy and a preparation method thereof.

Background

Since the Co-Cr-Mo alloy has excellent mechanical properties, wear resistance and corrosion resistance, it is practically effective as an implant material for artificial knee and hip joints and an implant material for dental use. The product is mainly prepared by molding and processing through a casting method. A typical ASTM standard F75 alloy of Co — Cr — Mo alloys has a structure mainly composed of a dendrite structure mainly including a Co-rich γ (f.c.c.) phase, an M23C6 carbide phase containing Co and Mo under Cr-rich conditions, and a Cr-and Mo-rich σ phase. The cast material has various casting defects such as hard and brittle precipitates, segregation, shrinkage cavities or bubbles, and the presence of these defects causes damage or cracks during processing, thereby impairing the mechanical reliability of the material.

When the Co-Cr-Mo alloy is used in the fields of artificial false teeth and the like, the Co-Cr-Mo alloy needs to be processed into a thin rod shape, and because of the hard and brittle nature of the Co-Cr-Mo alloy, an investment casting method is generally used for forming the Co-Cr-Mo alloy at present, but the investment casting process is complex and has low efficiency, and the casting can cause thick product tissues and low density, thereby influencing the service performance of the material.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems in the prior art, the invention provides the Co-Cr-Mo-N alloy and the preparation method thereof, the Co-Cr-Mo-N alloy is processed and formed into a thin rod by using a rolling method, the processing technology is simple, the processing efficiency is effectively improved, the product structure is refined, the coarse phase is crushed, the density is improved, and the mechanical property of the material is improved.

The technical scheme is as follows: the invention provides a preparation method of a Co-Cr-Mo-N alloy, which comprises the following steps: vacuum smelting: vacuum degree is less than or equal to 10^-2Pa, the smelting temperature is 1550-1680 ℃; pretreating Co, Cr and Mo single components or their binary or their ternary alloy, adding them into crucible, vacuumizing until the vacuum degree is less than or equal to 10^-2Pa; heating to melt, controlling the temperature to be 1620-1680 ℃, and keeping the temperature for 1-3 h; regulating and controlling the components to ensure that the components of other elements except the N element are reasonable; adding N, and performing electromagnetic stirring to meet the requirements of components and uniformity; preserving the heat for 0.5-1 h, detecting the components, and regulating and controlling the components to be qualified; vacuum casting: cooling the melt to 1480-1520 ℃, preserving the temperature for 0.1-0.5 h, and then casting the melt into a product with the length of 50-2000 m in a vacuum casting chamberm, a bar with the diameter of 30-80 mm; transferring the bar material to a heat treatment furnace when the temperature of the bar material is reduced to below 1200 ℃; and (3) heat treatment: controlling the furnace temperature at 1050-1250 ℃, keeping the temperature for 3-20 h, and discharging and air cooling; heating the cooled bar to 300-550 ℃, preserving heat for 1-20 h, then rapidly heating to 1150-1350 ℃, and preserving heat for 0.2-1 h; rolling: star-shaped rolling is carried out on the bar material at a high temperature, the single-time rolling amount is 10-18%, and the final rolling diameter is 8-10 mm; cutting: cutting according to the requirement, wherein the length is 20-50 mm.

Preferably, in the rolling step, the normal angle of the roller of the star rolling is 90 degrees or 120 degrees, and the rolling speed is 1-10 m/min.

Preferably, in the smelting step, N is added by adding a nitride.

Preferably, in the vacuum melting step, the binary alloy raw materials of cobalt, chromium and molybdenum are cobalt-chromium alloy and cobalt-molybdenum alloy.

Preferably, in the vacuum melting step, the ternary alloy raw material of cobalt, chromium and molybdenum is a cobalt-chromium-molybdenum alloy.

Preferably, in the vacuum smelting step, the pretreatment method is any one or combination of the following: drying, cleaning, degreasing and crushing.

Preferably, the nitride is chromium nitride.

Preferably, in the smelting step, N is added by introducing nitrogen at 1320-1480 ℃ and keeping the temperature for 1-3 h. And the temperature of 1320-1480 ℃ is a solid-liquid phase temperature range, nitrogen is introduced at the temperature to maximally dissolve nitrogen, the nitrogen is decomposed into free nitrogen atoms at the temperature, and the nitrogen atoms diffuse into the melt under the concentration trend and are dissolved in crystal lattices or form nitrides, so that the purpose of increasing the nitrogen is achieved.

The invention also provides a Co-Cr-Mo-N alloy prepared by the preparation method.

Preferably, the Co-Cr-Mo-N alloy consists of the following components in percentage by weight: 27-30% of Cr, 5-7% of Mo, 0.1-0.5% of N, 0.2-0.35% of C, less than or equal to 1% of Mn, less than or equal to 1% of Si, less than or equal to 0.5% of Ni, less than or equal to 0.75% of Fe, less than or equal to 0.2% of W, less than or equal to 0.02% of P, less than or equal to 0.01% of S, less than or equal to 0.03% of Al, less than or equal to 0.1% of Ti.

Has the advantages that: compared with the prior art, the invention has the following advantages:

the Co-Cr-Mo-N alloy is a quaternary alloy, has a large solid-liquid phase temperature range, is difficult to fill during solidification, is easy to form shrinkage cavity and shrinkage porosity defects, and is rolled to close casting pores of the Co-Cr-Mo-N alloy so as to improve the density;

2. casting quaternary Co-Cr-Mo-N alloy under non-quenching condition, easily forming coarse second phase at crystal boundary to form Widmannstatten structure, so as to sharply reduce plasticity and toughness of the material, deteriorate material performance, produce a large amount of plastic deformation by rolling, break brittle Widmannstatten structure and improve material performance;

3. the Co-Cr-Mo-N alloy material has anisotropic characteristics by rolling, and the second phase is arranged along the rolling direction, so that the unidirectional compression resistance of the material is improved, and the unidirectional stress requirement of dental and orthopedic materials is met, so that the rolled product can better meet the use requirement;

4. compared with an investment casting Co-Cr-Mo-N alloy rod, the rolled bar has the advantages of simple process, high production efficiency and low cost;

5. the bar after heat treatment has uniform components, eliminates coarse and large crystal boundary phases and reduces stress.

Detailed Description

The present invention will be described in detail with reference to specific examples.