阅读说明：本技术 用于铸锭的往复压剪耦合镦粗方法 (Reciprocating pressure-shear coupling upsetting method for cast ingot ) 是由 仇平 赵长财 朱麒 刘俊铭 于 2021-08-30 设计创作，主要内容包括：本发明提供一种用于铸锭的往复压剪耦合镦粗方法,其包括：S1、预镦粗阶段：将上平砧单向初始压下,下平砧保持不动,通过上下平砧压紧夹住铸锭；S2、主变形阶段：上平砧持续下压,下平砧开始往复平移,对铸锭开始进行耦合镦粗,对饼类锻件可一次完成耦合镦粗主变形阶段；对非饼类锻件需翻转镦粗的,每次翻转都可按照S2方法进行镦粗,直至完成开坯主变形阶段；S3、压实平整阶段。本发明通过步骤S2的压剪耦合镦粗方法使铸锭内部产生较大的塑性变形,充分发挥剪应变的作用,进而提高铸锭心部的锻透性,达到细化晶粒、锻合孔洞疏松和消除偏析等目的,以大幅提高坯料质量。(The invention provides a reciprocating pressure-shear coupling upsetting method for ingot casting, which comprises the following steps of: s1, pre-upsetting stage: the upper flat anvil is initially pressed down in one direction, the lower flat anvil is kept still, and the cast ingot is clamped by the upper flat anvil and the lower flat anvil in a pressing mode; s2, main deformation stage: the upper flat anvil is continuously pressed downwards, the lower flat anvil starts to perform reciprocating translation, the ingot casting starts to be subjected to coupling upsetting, and a main deformation stage of the coupling upsetting can be completed for cake forgings at one time; upsetting non-cake forgings in a turning mode, wherein upsetting can be carried out according to an S2 method when the forgings are turned each time until the cogging main deformation stage is completed; and S3, compacting and flattening. According to the invention, the pressing-shearing coupling upsetting method of the step S2 is adopted to generate larger plastic deformation in the ingot, so that the shearing strain effect is fully exerted, the forging permeability of the center of the ingot is further improved, the purposes of grain refinement, loose forged hole, segregation elimination and the like are achieved, and the quality of the blank is greatly improved.)

1. A reciprocating pressure-shear coupling upsetting method for ingot casting is characterized by comprising the following steps: which comprises the following steps:

s1, pre-upsetting stage: firstly, the upper flat anvil is initially pressed down in a single direction, the lower flat anvil keeps the initial position still, and the cast ingot is clamped by the compression of the upper flat anvil and the lower flat anvil;

s2, main deformation stage: go up flat hammering block and continue to push down, flat hammering block begins to carry out reciprocating translation motion in the horizontal plane down simultaneously, and the main deformation stage of cogging is accomplished in the coupling upsetting of the pressure strain of going up flat hammering block effect and the shearing strain of flat hammering block effect down, makes the central regional grain size of deforming of ingot casting can obtain fully refining through the effect of increasing shearing strain to forging permeability, and concrete main deformation work flow is:

for cake forgings, the lower flat anvil selects the optimal translation amount, translation direction and reciprocating times under the condition that the material plasticity is allowed and the cast ingot is clamped by the upper flat anvil, and the cogging main deformation stage is completed by one-time coupling upsetting according to the steps within the rolling reduction threshold of the upper flat anvil;

for non-cake forgings, when upsetting and drawing out are deformed alternately, the lower flat anvil selects the optimal translation amount, translation direction and reciprocating times to carry out primary press-shearing coupling upsetting according to the steps in the range allowed by material plasticity and under the condition that the cast ingot is clamped by the upper flat anvil, then the cast ingot is turned over, the translation amount, translation direction and reciprocating times of the lower flat anvil are updated according to the size of the blank after primary upsetting, the steps are repeated to carry out press-shearing coupling upsetting again, and the blank opening main deformation stage is completed after the process of multiple turning upsetting;

s3, compacting and flattening: and the lower flat anvil returns to the initial position and keeps static, the upper flat anvil continues to press downwards until the final size position of the blank is met, and then the action is stopped, the forge piece is further compacted, and the end face is flattened.

2. The reciprocating pressure-shear coupled upsetting method for ingot casting as recited in claim 1, wherein: the reciprocating translation of the lower flat anvil comprises a unidirectional reciprocating translation motion and/or a multidirectional reciprocating translation motion.

3. The reciprocating pressure-shear coupled upsetting method for ingot casting as recited in claim 1, wherein: step S1 further includes heating the ingot, and pre-upsetting the heated ingot with the upper and lower flat anvils.

4. The reciprocating pressure-shear coupled upsetting method for ingot casting as recited in claim 1, wherein: the translational movement of the lower flat anvil in step S2 includes a linear movement or a curved movement.

5. The reciprocating pressure-shear coupled upsetting method for ingot casting as recited in claim 1, wherein: the magnitude of the upper flat anvil reduction threshold in the step S1 is determined according to the friction coefficient between the forging stock and the contact surface of the upper flat anvil and the lower flat anvil, so that the cast ingot is ensured not to slide in the upsetting process of the step S2.

6. The reciprocating pressure-shear coupled upsetting method for ingot casting as recited in claim 1, wherein: the translation distance of the lower flat anvil in the step S2 is more than 0.3 times of the initial ingot diameter value, and the blank is ensured not to topple.

7. The reciprocating pressure-shear coupled upsetting method for ingot casting as recited in claim 1, wherein: the magnitude of the upper flat anvil depression amount threshold in step S4 is determined in accordance with the flat end face distance.

Technical Field

The invention belongs to the technical field of material forging, and particularly relates to a reciprocating press-shear coupling upsetting method for ingot casting, which gives full play to a shear strain method to improve the internal quality of a forging stock.

Background

Upsetting is a forging process that reduces the height of the billet and increases the cross-section. When the local cross section of the billet is increased, the local upset is called local upsetting. The upsetting function comprises the steps of obtaining a forging with a larger cross section and a smaller height from a blank with a smaller cross section; the cross section and the flat end surface of the blank are enlarged before punching; the forging ratio during the next step of drawing is improved; the transverse mechanical property of the forge piece is improved, and the anisotropy is reduced; repeated upsetting and stretching are carried out to break up carbide in the alloy tool steel so as to ensure that the carbide is uniformly distributed.

At present, the ingot cogging is mostly carried out by utilizing the positive pressure of an upper flat anvil and a lower flat anvil, and in order to obtain better blank making quality, a method of large rolling reduction is often adopted for upsetting to improve the blank quality.

However, the existing process still has a plurality of defects for improving the blank quality:

(1) because of the friction between the working anvil and the contact surface of the blank, the deformation of the core of the ingot is extremely uneven, and the integral quality of the blank is not stable;

(2) during upset upsetting, holes may reappear near the horizontal symmetry plane and the vertical symmetry plane of the forging stock due to repeated action of large tensile stress, and new loosening defects may be generated in diagonal regions due to repeated action of shear strain, so that a high-quality blank cannot be obtained.

(3) The temperature is easy to rise in the large deformation process of the central area of the forging stock, so that broken grains can quickly grow again, and the effect of grain refinement is not good;

(4) defects such as segregation and white spots are mainly self-diffusion, and are difficult to eliminate.

Disclosure of Invention

In order to solve the defects of the prior art, the invention ensures that the inner part of the cast ingot generates larger plastic deformation by a pressing and kneading method, fully exerts the effect of shear strain, further improves the forging penetration of the core part of the cast ingot, and achieves the purposes of grain refinement, loosening of forged holes, segregation elimination and the like, thereby greatly improving the quality of the blank.

The invention aims to cancel the constraint condition that a lower flat anvil is fixed in the existing upsetting method, increase the reciprocating translational motion of the lower flat anvil, combine with the positive pressure upsetting of the upper flat anvil, refine the defects of coarse grains inside in a crushing mode, forge the defects of loose holes inside, rub-off segregation and the like through the coupling action of pressure strain and shear strain, and realize the high-quality cogging of cast ingots.

Specifically, the invention provides a reciprocating pressure-shear coupling upsetting method for ingot casting, which comprises the following steps of:

s1, pre-upsetting stage: firstly, the upper flat anvil is initially pressed down in a single direction, the lower flat anvil keeps the initial position still, and the cast ingot is clamped by the compression of the upper flat anvil and the lower flat anvil;

s2, main deformation stage: go up flat hammering block and continue to push down, flat hammering block begins to carry out reciprocating translation motion in the horizontal plane down simultaneously, and the main deformation stage of cogging is accomplished in the coupling upsetting of the pressure strain of going up flat hammering block effect and the shearing strain of flat hammering block effect down, makes the central regional grain size of deforming of ingot casting can obtain fully refining through the effect of increasing shearing strain to forging permeability, and concrete main deformation work flow is:

for cake forgings, the lower flat anvil selects the optimal translation amount, translation direction and reciprocating times under the condition that the material plasticity is allowed and the cast ingot is clamped by the upper flat anvil, and the cogging main deformation stage is completed by one-time coupling upsetting according to the steps within the rolling reduction threshold of the upper flat anvil;

for non-cake forgings, when upsetting and drawing out are deformed alternately, the lower flat anvil selects the optimal translation amount, translation direction and reciprocating times to carry out primary press-shearing coupling upsetting according to the steps in the range allowed by material plasticity and under the condition that the cast ingot is clamped by the upper flat anvil, then the cast ingot is turned over, the translation amount, translation direction and reciprocating times of the lower flat anvil are updated according to the size of the blank after primary upsetting, the steps are repeated to carry out press-shearing coupling upsetting again, and the blank opening main deformation stage is completed after the process of multiple turning upsetting;

s3, compacting and flattening: and the lower flat anvil returns to the initial position and keeps static, the upper flat anvil continues to press downwards until the final size position of the blank is met, and then the action is stopped, the forge piece is further compacted, and the end face is flattened.

Preferably, the reciprocating translation of the lower flat anvil comprises a unidirectional reciprocating translation motion and/or a multidirectional reciprocating translation motion.

Preferably, in step S1, the heated metal ingot is first pre-upset using an upper flat anvil and a lower flat anvil.

Preferably, the magnitude of the rolling reduction threshold in step S1 is determined according to the friction coefficient between the forging stock and the contact surfaces of the upper and lower flat anvils.

Preferably, the rolling reduction threshold in step S1 is of such a magnitude that the contact surface of the forging stock with the upper flat anvil and the lower flat anvil does not slide during the upsetting by the press-shear coupling.

Preferably, the single-side translation distance of the lower flat anvil in the step S2 is greater than 0.3 times the value of the initial ingot diameter, and the blank is guaranteed not to topple.

Preferably, the reciprocating translation of the lower flat anvil in step S2 includes a linear motion or a curvilinear motion.

Compared with the prior art, the invention has the following beneficial effects:

(1) the upsetting method is suitable for large-size forgings, and can reduce the overturning frequency and improve the machining efficiency compared with the existing upsetting method under a reasonable process.

(2) According to the invention, the reciprocating translation motion of the lower flat anvil is increased, the positive pressure upsetting of the upper flat anvil is combined, and the defects of coarse grains inside, loose holes inside a forged part, breaking segregation and the like are refined in a crushing mode through the coupling action of pressure strain and shearing strain, so that the high-quality cogging of the cast ingot is realized.

(3) According to the invention, the greater plastic deformation is generated inside the ingot by a compression strain and shear strain coupling method, the effect of shear strain is fully exerted, the forging penetration of the core part of the ingot is further improved, and the purposes of grain refinement, loosening of forged holes, segregation elimination and the like are achieved, so that the quality of the blank is greatly improved.

(4) The method can finish cogging for the round cake forge piece by one-time coupling upsetting. When the forging ratio (the ratio of the blank height before upsetting to the blank height after upsetting) is 1.6 and the traverse ratio (the ratio of the blank diameter before upsetting to the single-side translation amount of the lower anvil) is 3.3, the internal grain refining quality is equivalent to that when the forging ratio under upsetting of the traditional flat anvil is 2 (which is often taken as the lower limit), and the method is favorable for improving the working efficiency. In a word, the lower anvil can achieve better quality effect by selecting parameters such as reasonable translation amount, translation direction, reciprocating times and the like within the range allowed by material plasticity and under the condition that the cast ingot is clamped by the upper flat anvil.

Drawings

FIG. 1 is a schematic diagram of conventional flat anvil upsetting and cogging of a conventional ingot.

Fig. 2 is a schematic view of the working process of the present invention.

FIG. 3 is a schematic diagram of one-way prepressing of the upper flat anvil according to the present invention.

FIG. 4 is a schematic view of the translation of the lower flat anvil to the right according to the present invention.

FIG. 5 is a schematic view of the left translation of the lower anvil of the present invention.

FIG. 6 is a schematic view of the lower flat anvil of the present invention.

FIG. 7 is a schematic view of the one-way final pressing of the upper flat anvil according to the present invention.

FIG. 8 is a schematic diagram of the internal grain distribution structure of the sample under the conventional flat anvil upsetting method.

FIG. 9 is a schematic view of the internal grain distribution structure of an example of the inventive process.

Some of the reference numbers in the figures are as follows:

1-upper flat anvil, 2-ingot casting contour before upsetting, 3-forging blank contour in upsetting process, 4-lower flat anvil, 5-hard deformation area and 6-central deformation area; 7-hard deformation area, 8-central deformation area.

Detailed Description

Exemplary embodiments, features and aspects of the present invention will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers can indicate functionally identical or similar elements. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

FIGS. 3-7 are schematic views showing the operation of each part, and FIG. 8 is a schematic view showing the distribution structure of recrystallized grains in the forging stock after normal flat anvil positive pressure upsetting. FIG. 9 is a schematic view showing the distribution structure of recrystallized grains inside the upset forging blank according to the process of the present invention.

The invention provides a reciprocating pressure-shear coupling upsetting method for ingot casting, which comprises the following steps of:

s1, pre-upsetting stage: firstly, the upper flat anvil 1 is initially pressed in a one-way mode, the lower flat anvil 4 is kept still, the cast ingot is clamped through the upper flat anvil 1 and the lower flat anvil 4 in a pressing mode, and the pressing amount of the upper flat anvil 1 is within the pressing amount threshold value.

During specific work, the upper flat anvil 1 and the lower flat anvil 4 are used for pre-upsetting the heated metal cast ingot. The ingot casting is initially pressed down by the upper flat anvil 1 and the lower flat anvil 4, so that the contact surfaces of the upper flat anvil 4 and the lower flat anvil 4 and the ingot casting generate enough positive pressure and friction force, the contact surfaces of the forging stock and the upper flat anvil 4 do not slip in the subsequent process, and preparation is made for reciprocating press-shear coupling upsetting.

S2, main deformation stage: the upper flat anvil 1 is continuously pressed downwards, the lower flat anvil 4 starts to perform reciprocating translation movement, ingot casting cogging is simultaneously completed through coupling upsetting of pressure strain acted by the upper flat anvil 1 and shear strain acted by the lower flat anvil 4, and the internal forging penetrability of a blank is improved through the increased shear strain of the lower flat anvil 4.

In the working process, technological parameters such as the rolling reduction of the upper flat anvil 1, the translation amount of the lower flat anvil 4, the motion mode of the lower flat anvil 4 and the like are reasonably set, and the purpose of high-quality cogging can be achieved.

And for cake forgings, the lower flat anvil 4 selects the optimal translation amount, translation direction and reciprocating times within the range allowed by material plasticity and under the condition that the cast ingot is clamped by the upper flat anvil 1, and cogging is completed by one-time coupling upsetting. In the process of continuously pressing down the upper flat anvil 1, the height of the cast ingot is smaller and smaller, the cross section is larger and larger, so that the cast ingot is more and more stable, meanwhile, the clamping force of the upper flat anvil and the lower flat anvil is also continuously increased, the blank is more favorable for preventing slipping and toppling, therefore, the translation amount of the lower flat anvil 4 can be adjusted to be larger in a follow-up mode, the deformation of the core is increased as much as possible, and the quality of the core is optimally improved. When the forging ratio (the ratio of the blank height before upsetting to the blank height after upsetting) is 1.6 and the traverse ratio (the ratio of the blank diameter before upsetting to the single-side translation amount of the lower anvil) is 3.3, the internal grain refinement quality is equivalent to that when the traditional upsetting lower forging ratio is 2 (often used as a lower limit), and the method is favorable for improving the working efficiency. In a word, the lower anvil can achieve better quality effect by selecting parameters such as reasonable translation amount, translation direction, reciprocating times and the like within the range allowed by material plasticity and under the condition that the cast ingot is clamped by the upper flat anvil 1.

When other non-cake forgings are alternatively deformed by upsetting and drawing, the first coupling upsetting and cogging steps are the same as those of the cake forgings, and the lower flat anvil 4 selects the optimal translation amount, translation direction and reciprocating times to perform the first coupling upsetting and cogging in the range of material plasticity and under the condition that the cast ingot is clamped by the upper flat anvil 1. And after the first coupling upsetting and cogging are finished, turning the cast ingot, repeating the steps, pressing, shearing and coupling upsetting again, and finishing the coupling upsetting stage according to the method. Because the shape and the size of the blank are changed after the previous step of coupled upsetting, the technological parameters of each step need to be reset after the blank is turned over, so as to ensure that the pressure-shear coupled upsetting is smoothly carried out and the cogging main deformation stage is completed.

S3, compacting and flattening: the lower flat anvil 4 returns to the initial position and is still, the upper flat anvil 1 continues to be pressed down until the position meeting the final size of the blank stops, the forge piece is further compacted, and the end face is flattened.

The movement of the lower flat anvil 4 comprises a unidirectional reciprocating translational movement and/or a multidirectional reciprocating translational movement. It can move in a linear or curvilinear manner.

In actual production, the physical properties of the material, the friction coefficient between the two anvils and the cast ingot, the rolling reduction of the upper flat anvil 1 and the translation mode of the lower flat anvil 4 are set according to specific working conditions.

Preferably, no lubricant is added to the surface of the ingot before upsetting the ingot in step S1.

The implementation of the technical scheme of the invention mainly lies in the design of the process of the reciprocating pressure-shear coupling upsetting method for ingot casting, and the translation structure of the lower flat anvil 4 and the press need to be additionally designed, which is not limited in the patent.

Example (b):

the process flow of the invention is illustrated by taking the upsetting of the ingot with the size of 500mm in diameter and 600mm in height as an example. FIG. 1 is a schematic diagram of upsetting and cogging of a traditional flat anvil of an ingot, wherein the reduction of an upper flat anvil 1 is 200mm, namely the height of a forging stock after upsetting and cogging is 400 mm. Other working conditions are as follows: the material is IN718 alloy, the initial grain size is 50 μm, the heating temperature is 1100 ℃, and the friction coefficient is 0.7. The ingot profile 2 before upsetting is shown as reference numeral 2.

As shown in FIG. 3, the process of the present invention is a one-way prepressing process of the upper flat anvil 1, and the rolling reduction of the upper flat anvil 1 is 25 mm. At the moment, sufficient pressure and friction force are generated on the upper end face and the lower end face of the cast ingot, so that the contact surface of the forging stock and the upper flat anvil 4 and the lower flat anvil 4 does not slide when the pressing-shearing coupling upsetting is carried out.

As shown in fig. 4, in the process flow of the present invention, the upper flat anvil 1 continues to be pressed down and the lower flat anvil 4 starts to translate, the total pressing amount of the upper flat anvil 1 is 75mm, and the lower flat anvil 4 translates 100mm to the right. From the profile deformation trend, the middle part of the forging stock is subjected to right offset deformation, so that the internal shear strain is increased, and the coarse grains are favorably crushed.

As shown in FIG. 5, the process of continuously pressing down the upper flat anvil 1 and horizontally moving the lower flat anvil 4 to the left in the process flow of the present invention is shown, the total pressing amount of the upper flat anvil 1 is 150mm, and the lower flat anvil 4 is horizontally moved to the left by 200 mm. From the profile deformation trend, the middle part of the forging stock is subjected to leftward offset deformation, and complex and large strain is generated inside the forging stock under the leftward and rightward reciprocating offset and the positive pressure of the upper flat anvil 1, so that the forging penetration is increased, and the refining of crystal grains, the loosening of press holes and the kneading and breaking of segregation tissues are facilitated. The upsetting process forging profile 3 is shown as 3.

As shown in fig. 6, in the process flow of the present invention, the upper flat anvil 1 continues to be pressed down and the lower flat anvil 4 returns, the total pressing amount of the upper flat anvil 1 is 175mm, and the lower flat anvil 4 moves 100mm to the right. From the trend of profile deformation, the forging blank is close to the traditional profile to approach the required specification shape of the forging blank.

As shown in FIG. 7, the final pressing process of the upper flat anvil 1 in the process flow of the invention is that the total pressing amount of the upper flat anvil 1 is 200mm, and the lower flat anvil 4 is not moved. The purpose is to flatten the end faces and further compact the metal inside.

As shown in FIG. 8, the recrystallized grain size of the central deformation region 6 of the forging stock after normal flat anvil positive pressure upsetting is more than 50 μm, the maximum value is 58 μm, it can be seen that the grains in the region grow again, and the central deformation region 6 is measured to account for 2% of the total volume; the hard deformation area 5 is conical, the cone top is deep into the central area, and the recrystallized grain size of the area is 45-50 μm.

As shown in FIG. 9, the recrystallized grain sizes of the whole forging stock after upsetting by compression-shear coupling are all less than 50 μm, wherein the central deformation region 8 of the forging stock is a region with smaller grain size, the minimum value is 17 μm, and the region with the measured grain size less than 27 μm accounts for 17% of the total volume; the hard deformation area 7 is an oblate body, the volume is smaller than that of the normal flat anvil positive pressure upsetting, and the recrystallized grain size of the area is between 40 and 50 mu m.

Finally, it should be noted that: the above-mentioned embodiments are only used for illustrating the technical solution of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.