阅读说明：本技术 Gh3128合金棒材制备方法 (Preparation method of GH3128 alloy bar ) 是由 赖宇 刘庭耀 付建辉 蒋世川 于 2019-10-22 设计创作，主要内容包括：本发明涉及高温合金锻造方法领域,尤其是一种有效实现低钨GH3128棒材成型,同时棒材组织均匀且μ相时效析出量降低的GH3128合金棒材制备方法,包括如下步骤：a、将低钨含量的电渣锭进行均匀化热处理；b、将均匀化热处理后的电渣锭进行两道次预压实拔长；c、进行一火次四道次径锻开坯,整形到尺,随后空冷车修成型。本发明在均匀化之后先进行预压实拔长,有利于电渣锭铸态组织的破碎,实现组织转变为等轴晶,为并将此作为径锻成型的中间坯。本发明尤其适用于GH3128合金棒材制备工艺之中。(The invention relates to the field of high-temperature alloy forging methods, in particular to a preparation method of a GH3128 alloy bar, which can effectively realize the forming of a low-tungsten GH3128 bar, has uniform bar structure and reduced mu-phase precipitation yield, and comprises the following steps: a. carrying out homogenization heat treatment on the electroslag ingot with low tungsten content; b. carrying out two times of pre-compaction and drawing on the electroslag ingot after the homogenization heat treatment; c. and performing one-fire four-pass radial forging cogging, shaping to a ruler, and then performing air cooling and vehicle repairing molding. The invention carries out pre-compaction and drawing-out after homogenization, is beneficial to crushing the cast structure of the electroslag ingot, realizes the transformation of the structure into isometric crystal, and takes the isometric crystal as an intermediate billet for radial forging forming. The invention is particularly suitable for the preparation process of the GH3128 alloy bar.)

The preparation method of the GH3128 alloy bar is characterized by comprising the following steps:

a. firstly, carrying out homogenization heat treatment on an electroslag ingot with low tungsten content;

b. carrying out pre-compaction and drawing-out twice on the electroslag ingot after the homogenization heat treatment, wherein the deformation of the pre-compaction and drawing-out twice is 20-30% in the first pass, and the deformation of the pre-compaction and drawing-out twice is 25-35% in the second pass, so as to break the as-cast structure of the electroslag ingot;

c. performing one-fire four-pass radial forging cogging, wherein the striking frequency of 90 times/min is adopted in the first pass, the deformation is 5-10%, and the bar is rounded; the striking frequency of the second pass is 180 times/min, the deformation is 25% -30%, and the recrystallization of the forged bar tissue is realized; the deformation amount of the third striking frequency is 15-20% at 180 times/min, the whole deformation of the bar is coordinated, and the uniformity of the structure is increased; and the striking frequency of the fourth pass is 180 times/min, shaping to a ruler, and then performing air cooling and vehicle repairing and molding.

2. The method of preparing GH3128 alloy rods of claim 1, wherein: in step a, the homogenization heat treatment is carried out at 1150 ℃ for 5 hours.

3. The method of making GH3128 alloy rods of claims 1 or 2, wherein: in the step b, the drawing mode is anvil drawing.

Technical Field

The invention relates to the field of high-temperature alloy forging methods, in particular to a GH3128 alloy bar preparation method.

Background

GH3128 is a nickel-based alloy which is solid-solution-strengthened by tungsten and molybdenum and grain boundaries are strengthened by boron, cerium and zirconium, and has high plasticity, high creep strength, good oxidation resistance, stamping, welding and other properties. GH3128 is mainly used in the fields of gas turbine engine and combustor flame tube working for a long time below 950 deg.C. With the technological progress and the change of alloy application environment, the alloy performance is continuously required, and it is known from aviation material handbooks that the alloy has a solid solution content of more than 8 percent, and tungsten increases the precipitation tendency of a mu phase in the alloy, which seriously affects the endurance and fatigue performance of the alloy.

In both patent 201510848784.8 and patent 201611149289.9, multiple-fire repeated upsetting and drawing process is adopted for preparing GH4169 alloy bars, but the temperature after forging needs to be strictly controlled, and the problem of large particle precipitation still exists. In patent 201810749244.8, aiming at homogenization of alloy grains, a multi-fire transverse and radial upsetting and drawing process is adopted to prepare an alloy bar material GH3128, which is beneficial to realization of uniformity of grains in all directions, but the processing and forming time is increased, the heating and heat preservation cost is increased for multiple fire times, and the forging temperature is difficult to control. At present, no technological method capable of controlling the uniformity of the structure and the aging precipitation of the mu phase by taking GH3128 into account exists.

Disclosure of Invention

The invention aims to provide a preparation method of a GH3128 alloy bar, which can effectively realize the forming of a low-tungsten GH3128 bar and has uniform bar structure and reduced mu-phase precipitation amount.

The technical scheme adopted by the invention for solving the technical problems is as follows: the preparation method of the GH3128 alloy bar comprises the following steps: a. firstly, carrying out homogenization heat treatment on an electroslag ingot with low tungsten content; b. carrying out pre-compaction and drawing-out twice on the electroslag ingot after the homogenization heat treatment, wherein the deformation of the pre-compaction and drawing-out twice is 20-30% in the first pass, and the deformation of the pre-compaction and drawing-out twice is 25-35% in the second pass, so as to break the as-cast structure of the electroslag ingot; c. performing one-fire four-pass radial forging cogging, wherein the striking frequency of 90 times/min is adopted in the first pass, the deformation is 5-10%, and the bar is rounded; the striking frequency of the second pass is 180 times/min, the deformation is 25% -30%, and the recrystallization of the forged bar tissue is realized; the deformation amount of the third striking frequency is 15-20% at 180 times/min, the whole deformation of the bar is coordinated, and the uniformity of the structure is increased; and the striking frequency of the fourth pass is 180 times/min, shaping to a ruler, and then performing air cooling and vehicle repairing and molding.

Further, in step a, the homogenization heat treatment is performed by keeping the temperature at 1150 ℃ for 5 hours.

Further, in the step b, the drawing mode is anvil drawing.

The invention has the beneficial effects that: according to the invention, the electroslag cast ingot with reduced tungsten content is used as a forging stock of the forging rod, and the addition of tungsten element is reduced, so that the production cost can be reduced, the segregation can be reduced to a certain extent, and the mu-phase precipitation tendency can be reduced. Meanwhile, pre-compaction drawing is carried out after homogenization, which is beneficial to crushing of the cast structure of the electroslag ingot, realizes the transformation of the structure into isometric crystal and takes the isometric crystal as an intermediate billet for radial forging forming. In addition, the forging forming is directly carried out by one-time and four-time radial forging, so that the forging stock can be ensured to finish hot working below the rapid growth temperature of crystal grains and above the mu phase precipitation peak temperature, and meanwhile, the uniformity of the structure is improved through the matching of pass striking. The invention is particularly suitable for the preparation process of the GH3128 alloy bar.

Drawings

FIG. 1 is a crystal phase diagram of the core structure of the rod prepared by the present invention.

FIG. 2 is a crystallographic phase diagram of the structure at the 1/2 radius of a rod prepared in accordance with the present invention.

FIG. 3 is a crystal phase diagram of the surface structure of the rods prepared by the present invention.

FIG. 4 is a crystal phase diagram of an aging structure of a bar prepared by the invention.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

The preparation method of the GH3128 alloy bar shown in FIG. 1, FIG. 2, FIG. 3 and FIG. 4 comprises the following steps: a. firstly, carrying out homogenization heat treatment on an electroslag ingot with low tungsten content; b. carrying out pre-compaction and drawing-out twice on the electroslag ingot after the homogenization heat treatment, wherein the deformation of the pre-compaction and drawing-out twice is 20-30% in the first pass, and the deformation of the pre-compaction and drawing-out twice is 25-35% in the second pass, so as to break the as-cast structure of the electroslag ingot; c. performing one-fire four-pass radial forging cogging, wherein the striking frequency of 90 times/min is adopted in the first pass, the deformation is 5-10%, and the bar is rounded; the striking frequency of the second pass is 180 times/min, the deformation is 25% -30%, and the recrystallization of the forged bar tissue is realized; the deformation amount of the third striking frequency is 15-20% at 180 times/min, the whole deformation of the bar is coordinated, and the uniformity of the structure is increased; and the striking frequency of the fourth pass is 180 times/min, shaping to a ruler, and then performing air cooling and vehicle repairing and molding.

The production of high-temperature alloy bars usually adopts a combined forging process of 'quick forging, upsetting and cogging' plus 'one-fire-time or multiple-fire-time radial forging', the combined forging process is mainly used for large ingot type large-size bars or alloy bars requiring fine grains and strictly requiring extremely poor grains, the GH3128 alloy has a low critical value of dynamic recrystallization, dynamic recrystallization is easy to complete, and the grain growth sensitivity is mainly related to temperature, so that conditions are created for one-fire-time multiple-time radial forging forming of the GH3128 alloy bars. The GH3128 alloy bar material is prepared by adopting electroslag ingot of GH3128 with low tungsten content. Firstly, carrying out high-temperature homogenization heat treatment on an electroslag ingot, then pre-compacting, drawing and cogging with a certain deformation, and finally realizing bar preparation in a radial forging and cogging mode of one fire for multiple times. Specifically, after high-temperature homogenization heat treatment, pre-compaction and elongation are carried out for two times, an ingot blank is preliminarily compacted, loose shrinkage holes in the ingot blank are eliminated, and an as-cast structure is crushed to generate equiaxed grains. And the material is directly forged by one fire for four times, and uniform bar structures can be obtained by matching the pass deformation with the striking frequency, and the mu phase precipitation during aging is reduced.

In order to further optimize the preparation process and thus obtain more desirable product quality, the following scheme is preferred: in step a, the homogenization heat treatment is carried out at 1150 ℃ for 5 hours. Preferably, in step b, the drawing manner is anvil drawing.