阅读说明：本技术 高效钛及钛合金铸锭短流程精锻开坯工艺 (Efficient short-flow precision forging and cogging process for titanium and titanium alloy ingots ) 是由 蒋荣军 候宇鑫 国斌 赵炯 于 2019-08-07 设计创作，主要内容包括：本发明提供一种高效钛及钛合金铸锭短流程精锻开坯工艺,包括加热流程、径锻机精锻变形、检验和机加工流程,然后得到钛合金棒材：其中所述的加热流程采用环形加热炉、通过火焰加热实现对钛及钛合金锭坯的加热,在加热过程中采用预热、加热以及均热三个阶段实现,其中预热段的加热温度在800±50°,加热时间为60-70min；加热段的加热温度在900-1150°,加热时间70-90min,均热段的加热温度与加热段相当,均热时间为60-90min；径锻机精锻变形处理包括通过液压式径锻机进行精锻,使用四锤头进行锤击锻造,锻造时间10-30min。本发明采用改进加热方式的环形加热炉,通过环形分段加热的方式,并结合径锻机的锻造变形,实现钛及钛合金铸锭的快速、高效、短流程的制备。(The invention provides a short-flow precision forging and cogging process of a high-efficiency titanium and titanium alloy ingot, which comprises a heating flow, a radial forging machine precision forging deformation, an inspection and a machining flow, and then titanium alloy bars are obtained: wherein the heating process adopts an annular heating furnace, realizes the heating of the titanium and titanium alloy ingot blank by flame heating, and realizes the three stages of preheating, heating and soaking in the heating process, wherein the heating temperature of the preheating stage is 800 +/-50 ℃, and the heating time is 60-70 min; the heating temperature of the heating section is 900-1150 ℃, the heating time is 70-90min, the heating temperature of the soaking section is equivalent to that of the heating section, and the soaking time is 60-90 min; the finish forging deformation treatment of the radial forging machine comprises the steps of performing finish forging through a hydraulic radial forging machine, and performing hammering forging by using four hammers for 10-30 min. The invention adopts the annular heating furnace with an improved heating mode, realizes the fast, efficient and short-flow preparation of the titanium and the titanium alloy ingots by an annular sectional heating mode and the forging deformation of a radial forging machine.)

1. A short-flow precision forging and cogging process of high-efficiency titanium and titanium alloy ingots is characterized by comprising a heating flow, a radial forging machine precision forging deformation, an inspection flow and a machining flow, and then obtaining titanium alloy bars:

wherein the heating process adopts an annular heating furnace, realizes the heating of the titanium and titanium alloy ingot blank by flame heating, and realizes the three stages of preheating, heating and soaking in the heating process, wherein the heating temperature of the preheating stage is 800 +/-50 ℃, and the heating time is 60-70 min; the heating temperature of the heating section is 900-1150 ℃, the heating time is 70-90min, the heating temperature of the soaking section is equivalent to that of the heating section, and the soaking time is 60-90 min;

the finish forging deformation treatment of the radial forging machine comprises the steps of performing finish forging through a hydraulic radial forging machine, and performing hammering forging by using four hammers for 10-30 min.

2. The short-flow precision forging and cogging process of high-efficiency titanium and titanium alloy ingots according to claim 1, characterized in that in the heating process, the design of the annular heating furnace adopts a design that a heating section, a preheating section and a soaking section are mutually connected to form an annular shape, and charging and discharging are carried out between the preheating section and the soaking section.

3. The short-flow precision forging and cogging process of high-efficiency titanium and titanium alloy ingots according to claim 1, characterized in that during the heating process, the furnace bottom of the annular heating furnace rotates for one circle, so that the ingot blank sequentially and continuously passes through three areas of a heating section, a preheating section and a soaking section.

4. A high efficiency short pass precision forging cogging process for titanium and titanium alloy ingots according to claim 1, characterized in that during heating, the atmosphere in the ring-shaped heating furnace is slightly oxidizing.

5. A high efficiency short pass precision forging cogging process for titanium and titanium alloy ingots according to claim 1, wherein in the precision forging deformation process, the hammering frequency of the hammer head is lower than the frequency in the middle and later forging stages during the initial forging of the ingot, and the deformation speed and hammering frequency of each pass are gradually increased in the middle and later forging stages.

6. A high efficiency short pass precision forging cogging process for titanium and titanium alloy ingots according to claim 1, characterized in that in the final small deformation finish forging stage, the frequency of hammering is up to 240 per minute passes.

Technical Field

The invention relates to the technical field of titanium and titanium alloy bar forging, in particular to a high-efficiency short-flow precision forging and cogging process for titanium and titanium alloy ingots.

Background

Compared with copper, aluminum, iron and nickel, the titanium and titanium alloy heating process has low heat conductivity of titanium, and the main difficulty of heating is that the heating time is quite long when a surface heating method is adopted, and the temperature difference of the cross section is large when a large blank is heated. Unlike copper, iron, and nickel-based alloys, which decrease in thermal conductivity with increasing temperature, titanium alloys increase in thermal conductivity with increasing temperature.

However, when the heating temperature is increased, titanium and titanium alloys also react strongly with air. Titanium reacts strongly with oxygen when heated above 650 c, and also reacts with nitrogen above 700 c, forming a deeper surface layer saturated with both gases. For example, when a titanium ingot having a diameter of 350mm is heated to 1100 to 1150 by surface heating, it is necessary to uniformly heat the ingot for 3 to 4 hours or more in a temperature range in which titanium and a gas strongly react with each other, and a gettering layer having a thickness of 1mm or more may be formed. Such a getter layer deteriorates the deformability of the alloy.

Referring to fig. 1, in the prior art, a titanium alloy ingot cogging process generally includes heating, cogging forging, secondary heating, secondary forging deformation, inspection, and machining to prepare a bar, and even under some performance requirements, the process may further include three times of heating and forging deformation, so that the cogging process of the titanium alloy ingot is prolonged, and corresponding costs are increased greatly.

However, in addition to strict control of the quality of the production process of titanium alloy materials, the low-cost, high-efficiency and short-flow titanium and titanium alloy processing technology of titanium is a key influencing the wide application of titanium alloys in various industries, the current cost is still high, the low-cost preparation is more and more highly emphasized by development departments and titanium material production enterprises, and the problems of excellent performance, good surface quality and high material yield of the obtained titanium alloy bars are a key problem in the current titanium alloy bar production and preparation.

Disclosure of Invention

The invention aims to provide a short-flow precision forging and cogging process for high-efficiency titanium and titanium alloy ingots, which aims to solve the problems in the prior art, and realizes the rapid, high-efficiency and short-flow preparation of the titanium and titanium alloy ingots by adopting an annular heating furnace with an improved heating mode, and by adopting an annular sectional heating mode and combining the forging deformation of a radial forging machine.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the short-process precision forging and cogging process of the high-efficiency titanium and titanium alloy ingot comprises a heating process, a radial forging machine precision forging deformation, an inspection process and a machining process, and then the titanium alloy bar is obtained:

wherein the heating process adopts an annular heating furnace, realizes the heating of the titanium and titanium alloy ingot blank by flame heating, and realizes the three stages of preheating, heating and soaking in the heating process, wherein the heating temperature of the preheating stage is 800 +/-50 ℃, and the heating time is 60-70 min; the heating temperature of the heating section is 900-1150 ℃, the heating time is 70-90min, the heating temperature of the soaking section is equivalent to that of the heating section, and the soaking time is 60-90 min;

the finish forging deformation treatment of the radial forging machine comprises the steps of performing finish forging through a hydraulic radial forging machine, and performing hammering forging by using four hammers for 10-30 min.

Preferably, in the heating process, the design of the annular heating furnace adopts the design that the heating section, the preheating section and the soaking section are mutually connected into an annular shape, and the charging and discharging are carried out between the preheating section and the soaking section.

Preferably, during the heating process, the furnace bottom of the annular heating furnace rotates for one circle, so that the ingot blank sequentially and continuously passes through three areas of the heating section, the preheating section and the soaking section.

Preferably, during the heating, the atmospheric condition in the ring-shaped heating furnace is a micro-oxidation atmosphere.

Preferably, in the finish forging deformation process, the hammering frequency of the hammer head is lower than the hammering frequency in the middle and later forging stages when the ingot is initially forged, and the deformation speed and the hammering frequency of each pass are gradually increased in the middle and later forging stages.

Preferably, the pass reaches a hammering frequency of 240 per minute in the final small deformation finish forging stage.

By the technical scheme, the cogging process has the beneficial effects that: compared with the traditional free forging, the invention adopts the hydraulic forging machine, can realize higher forging speed and beating frequency than the common quick forging machine, and in the heating process, an improved annular heating furnace is adopted, the furnace bottom rotates for a circle, the ingot blank continuously passes through three areas of preheating, heating and soaking, the atmosphere environment in the furnace is controlled, the heating temperature and time of the titanium and titanium alloy ingot blank are effectively controlled, and the perfect implementation of the forging process of the radial forging machine is ensured.

The invention can shorten the retention time of the blank at high temperature by optimizing the sectional heating process of the titanium and titanium alloy materials and the forging deformation process of the hydraulic radial forging machine, solves the problems of low heat conductivity of the titanium and the titanium alloy and serious gas absorption at high temperature in the heating process, and realizes that the workpiece is kept in a relatively stable and narrow deformation temperature range in the deformation process by carrying out precision forging through the hydraulic radial forging machine and controlling the pass elongation and the deformation speed so as to obtain the optimal structure and performance.

Drawings

FIG. 1 is a flow chart of a prior art rapid forging (rapid forging) cogging process for titanium and titanium alloy ingots.

FIG. 2 is a flow chart of the short-flow precision forging and cogging process of the high-efficiency titanium and titanium alloy ingot.

Fig. 3 is a schematic view of a ring-shaped heating furnace used in the cogging process of the present invention.

FIG. 4 is a schematic representation of the microstructure of a Ti-Fe-B alloy in a prior art rapid forging process.

FIG. 5 is a schematic view of the microstructure of Ti-Fe-B alloy in the short pass finish forging process of the present invention.

FIG. 6 is a schematic representation of the TA1 alloy microstructure in a rapid forging process.

FIG. 7 is a schematic representation of the microstructure of the TA1 alloy in a short pass precision forging process according to the present invention.

FIG. 8 is a graph of the room temperature tensile stress strain of the TA1 alloy under the rapid and finish forge forging process.

Detailed Description

In order to better understand the technical content of the present invention, specific embodiments are described below with reference to the accompanying drawings.

In this disclosure, aspects of the present invention are described with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. Embodiments of the present disclosure are not necessarily intended to include all aspects of the invention. It should be appreciated that the various concepts and embodiments described above, as well as those described in greater detail below, may be implemented in any of numerous ways.

Referring to fig. 2, an embodiment according to various aspects of the present invention provides a short-process precision forging cogging process for titanium and titanium alloy ingots, which generally includes a heating process, a radial forging machine precision forging deformation process, an inspection process and a machining process, and then titanium alloy bars are obtained.

Referring to fig. 2 and 3, the heating process of the invention adopts an annular heating furnace to heat the titanium and titanium alloy ingot blanks by flame heating. In a preferred embodiment, referring to FIG. 3, the annular heating furnace is composed of a fixed furnace wall and an annular rotary furnace bottom, and a water seal is arranged between an inner ring and an outer ring. The ingot blank continuously passes through three zones of preheating, heating and soaking by adopting a special loading and unloading mechanism, the furnace bottom rotates for a circle, and the ingot blank does not slide relative to the furnace bottom. The heating section, the preheating section and the soaking section are mutually connected into a ring design, and charging and discharging are carried out between the preheating section and the soaking section.

In order to ensure that the forge piece and the die forge piece obtain uniform fine grain structures and high mechanical properties, the three stages of preheating, heating and soaking are adopted in the heating process, wherein the heating temperature of the preheating section is 800 +/-50 ℃, and the heating time is 60-70 min; the heating temperature of the heating section is 900-1150 ℃, the heating time is 70-90min, the heating temperature of the soaking section is equivalent to that of the heating section, the soaking time is 60-90min, and the retention time of the blank at high temperature is ensured to be short.

In the embodiment of the invention, the annular heating furnace belongs to a flame heating furnace, and the control of the furnace atmosphere is mainly determined by the harmful influence of certain components and impurities in the furnace atmosphere on the alloy according to the characteristics of the interaction between the properties of the furnace atmosphere and the alloy. In the process of realizing the process, the atmosphere in the furnace is controlled to be a micro-oxidation atmosphere, the pressure of the hearth is improved, the air suck-back is prevented, and the hydrogen embrittlement crack generated by the hydrogen absorption of the ingot blank is avoided. Meanwhile, the material is charged by a hot furnace more preferably, and the material is charged after the forging, so that the waste heat is fully utilized, and the energy is saved; and the number of opened burners is reduced, the heating temperature and time of the titanium and titanium alloy ingot blank are effectively controlled, and the perfect implementation of the forging process of the radial forging machine is ensured.

Compared with the traditional free forging equipment, the process is realized by adopting a hydraulic radial forging machine, the finish forging deformation treatment comprises finish forging through the hydraulic radial forging machine, hammering forging is carried out by using four hammers, and the forging time is 10-30 min. In the process of finish forging deformation, when an ingot blank is initially forged, the hammering frequency of a hammer is lower than the hammering frequency in the middle and later forging stages, and the deformation speed and the hammering frequency of each pass are gradually increased in the middle and later forging stages.

Preferably, the pass reaches a hammering frequency of 240 per minute in the final small deformation finish forging stage.

By the precision forging process, the forging speed and the striking frequency which are much faster than those of a common quick forging machine can be obtained. Due to the self characteristic of hydraulic drive, stepless adjustment of forging speed and striking frequency can be realized according to the reduction of the hammer head, the return height and the load of each pass. Generally, the larger the reduction, the return stroke height and the load, the lower the forging speed and the striking frequency, and vice versa.

In the forging and cogging process, in order to ensure the core forging penetration, the elongation of each cogging pass is set as large as possible according to the plasticity of the material. Under a certain pass elongation, when an ingot blank is initially forged, the original size of the blank is large, and a large absolute reduction and a large forging force of the hammer head are required, so that the hammer head can obtain a slow deformation speed and a low striking frequency. In the forging process, the blank deforms along with each pass, the diameter before forging is gradually reduced, and the corresponding absolute reduction and forging force are also gradually reduced, so that the deformation speed and striking frequency of each pass are gradually increased, and the striking frequency of 240 times/minute can be realized in the final small-deformation finishing pass.

Because the blank has large deformation resistance and small heat conductivity coefficient, the thermal effect is obvious during deformation, the temperature rise phenomenon is obvious, and the forging overheating is easy to occur. When the ingot blank is initially forged, the diameter of the blank is relatively large, the length of the blank is relatively short, the surface heat dissipation temperature drop is small, and the low deformation speed and the striking frequency can prevent the temperature from rising too fast. Along with the reduction of the section of the blank, the length is increased, the surface heat dissipation and the temperature drop are rapid, the deformation heat can be increased by adopting the rapid deformation speed and the striking frequency, and the material temperature is prevented from being low.

Fig. 4-8 are microstructure morphologies and stress-strain curves of the short pass finish forge of the present invention compared to the forge of different titanium alloys under a conventional rapid forging process. FIG. 4 is a schematic representation of the microstructure of a Ti-Fe-B alloy in a prior art rapid forging process. FIG. 5 is a schematic view of the microstructure of Ti-Fe-B alloy in the short pass finish forging process of the present invention.

An ingot of 400mm diameter is converted by cogging into a rod of 120mm diameter. The two materials were deformed by the same amount. The microstructure of each region of the fast-forged and the finish-forged Ti-Fe-B alloys is shown in FIGS. 4 and 5, where S is abbreviated as "Surface", M is abbreviated as "middle", and C is abbreviated as "Core".

FIG. 6 is a schematic representation of the TA1 alloy microstructure in a rapid forging process. FIG. 7 is a schematic representation of the microstructure of the TA1 alloy in a short pass precision forging process according to the present invention. Referring to fig. 8, which is a tensile stress-strain curve of TA1 alloy at room temperature under the fast forging and finish forging processes, as shown in the alloy tensile property test results in table 1 below, it can be seen that the alloy material under the short-process forging process of the present invention has better tensile property and finer alloy structure.

TABLE 1 tensile Properties of TA1 alloy under two forging processes

Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention should be determined by the appended claims.