CN114160731B - A forging method for titanium alloy oblique T-shaped forging - Google Patents

Abstract

The invention belongs to the field of forging and die design, and particularly relates to a forging method of a titanium alloy inclined T-shaped forging. The method comprises the steps of heating a titanium alloy bar stock to a deformation temperature, freely forging to obtain a T-shaped blank, heating the T-shaped blank to the deformation temperature, rotating the T-shaped blank by 90 degrees on the basis of a horizontal plane, placing the T-shaped blank in a pre-forming die, forging the T-shaped blank by adopting the pre-forming die to obtain a pre-formed piece, wherein the pre-formed piece comprises an inclined boss and a bottom plate, the inclined boss protrudes downwards from the middle section of the bottom plate, the inclined boss occupies at least 3/4 of the space of the middle section, the parting surface of the pre-forming die is the largest cross section of the pre-formed piece, the largest cross section is a curved surface, heating the pre-formed piece to the deformation temperature, forging the pre-formed piece by using the pre-forging die, heating the pre-formed piece to the deformation temperature, and forging the pre-formed piece by using a final forging die to obtain a die forging piece.

Description

Forging method of titanium alloy inclined T-shaped forging

Technical Field

The invention belongs to the field of forging and die design, and particularly relates to a forging method of a titanium alloy inclined T-shaped forging.

Background

The titanium alloy oblique T-shaped forging is a complex die forging for aviation, is difficult to mold in one-time die forging and has larger influence on a die and forging equipment due to complex structural characteristics, and on the other hand, a rough blank is complex and difficult to realize, has larger deformation, is easy to crack and has unqualified performance.

Disclosure of Invention

The invention aims to design a forging method of a titanium alloy inclined T-shaped forging, which ensures that the good shape filling size of the forging meets the drawing requirement, has qualified performance and is simple and easy to realize.

The invention solves the problem of difficult forging forming by designing preforming, pre-forging and final forging and controlling reasonable forging process parameters, and has less damage to a die and forging equipment, simple and easy manufacture of the rough blank and qualified physicochemical properties.

In order to solve the technical problem, the technical scheme of the invention is as follows:

A forging method of a titanium alloy inclined T-shaped forging comprises the following steps:

heating the titanium alloy bar to a deformation temperature, and freely forging to obtain a T-shaped rough blank;

Heating a T-shaped blank to a deformation temperature, rotating the T-shaped blank by 90 degrees on the basis of a horizontal plane, placing the T-shaped blank in a pre-forming die, forging the pre-forming die to obtain a pre-forming piece, wherein the pre-forming piece comprises an inclined boss and a bottom plate, the inclined boss protrudes downwards from the middle section of the bottom plate, and the inclined boss occupies at least 3/4 of the space of the middle section;

Heating the preformed piece to a deformation temperature, and forging by using a pre-forging die to obtain a pre-forging piece;

and heating the pre-forging piece to a deformation temperature, and forging by using a final forging die to obtain the die forging piece.

Before heating the titanium alloy bar to the deformation temperature and free forging the blank to obtain a T-shaped rough blank, the method further comprises:

designing matched dies according to the outline dimension of the die forging, wherein the dies comprise a preformed die, a pre-forging die and a final-forging die;

and designing a T-shaped blank according to the outline dimension of the preformed forging.

For the preforming mould, according to die forging overall dimension design assorted mould, include:

Determining characteristic points of the preform on the parting surfaces of the upper die and the lower die according to the maximum cross section of the vertical preform;

sequentially connecting the starting point and the end point of the characteristic points to form a curve, wherein the curve formed by the curve is a curve parting surface of the mold, so that the preformed piece can be uniformly divided up and down, and the preformed mold is determined according to the parting surface and the outline dimension of the preformed forging piece;

The method comprises the steps of designing a preformed piece according to the outline dimension of the preformed piece, and carrying out equal-section equal-volume conversion, wherein the preformed piece is enabled to be uniformly deformed when being forged to the preformed piece, and the deformation is about 20% -50%.

According to die forging overall dimension design assorted mould includes:

Firstly, designing a final forging die matched with the shape of the hot forging according to the outline dimension of the hot forging;

the design of the pre-forging die is to design a final forging die matched with the pre-forging die in shape according to the outline dimension of the pre-forging piece, wherein the pre-forging piece is designed according to the outline dimension of the pre-forging piece and the equal-section equal-volume conversion, so that the pre-forging piece is guaranteed to be uniformly deformed when being forged to the final forging piece, and the deformation is about 20% -35%.

The size of the final forging die is designed by adopting a design formula, wherein the size of the final forging die is equal to ((the outline size of the forging) x (1+the thermal shrinkage rate of the material)).

Designing a T-shaped blank according to the outline dimension of the preformed forging, comprising:

adding 5mm under-pressure and 30mm wide and 8mm deep burrs on the basis of the equal section according to the outline dimension of the preformed piece close to the inclined T shape, and performing equal volume conversion to obtain an inclined T-shaped rough blank;

the same-section and equal-volume transformation of the inclined T-shaped rough blank into the T-shaped rough blank is adopted.

The preforming process comprises the following steps:

Heating the T-shaped rough blank in an electric furnace, wherein the heating standard is that the temperature is 35 ℃ below the phase change point, and the heat preservation time is calculated according to the heat preservation coefficient of 0.6-0.8 min/mm;

placing the heated and insulated T-shaped rough blank into a pre-forming die;

And hammering the pre-forming die by using 2800T three hammers to enable the T-shaped rough blank to be full of the cavity, wherein the hammering interval time is 15s, the first hammer is used for tapping and positioning, the second hammer is used for hammering the three hammers until the die is closed, the forging under-pressure is less than or equal to 5mm, and the final forging temperature is not lower than 820 ℃ to obtain the pre-forming piece.

The pre-forging process comprises the following steps:

Heating the preformed piece in an electric furnace, wherein the heating standard is that the temperature is 35 ℃ below the phase change point, and the heat preservation time is calculated according to the heat preservation coefficient of 0.6-0.8 min/mm;

Placing the heated and insulated preform into a pre-forging die;

Hammering the pre-forging die, wherein the forging hammering times are 3, the hammering interval time is 15s, the hammering energy of the first hammer 2800t, the hammering energy of the second hammer 4000t and the hammering energy of the third hammer 5600t are forged until the die is closed, the forging under-pressure is less than or equal to 5mm, and the final forging temperature is not lower than 820 ℃ to obtain the pre-forging.

The final forging process comprises the following steps:

Heating the pre-forging in an electric furnace, wherein the heating standard is that preheating is carried out at a temperature of 35 ℃ below a phase change point, the heat preservation time is calculated according to a heat preservation coefficient of 0.6-0.8 min/mm, the temperature is heated to 15 ℃ above the phase change point after the preheating is finished, and the heat preservation time is calculated according to a heat preservation coefficient of 0.25-0.5 min/mm;

Placing the heated and heat-preserving pre-forging piece into a final forging die;

And hammering the final forging die, wherein the forging times are 3, the hammering interval time is 15s, the first hammer is used for hammering energy of 20mm thick backing plates 2800t, the second hammer is used for hammering energy of 10mm thick backing plates 4000t, the third hammer is used for hammering energy of 5600t of backing plates until the die is closed, the under-pressure of the forging is less than or equal to 5mm, and the final forging temperature is not lower than 820 ℃ to obtain the die forging.

The forging method has the beneficial effects that reasonable forging parameters are controlled by designing the T-shaped rough blank, free forging blank, preforming, pre-forging and final forging, so that each procedure meets the requirements, and the forging with good filling and qualified performance is successfully obtained.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the following will simply explain the drawings that need to be used in the embodiments of the present invention. It is evident that the drawings described below are only examples of the invention, from which other drawings can be obtained for a person skilled in the art without inventive effort.

FIG. 1 is a schematic illustration of a forging provided by the present invention.

Fig. 2 is a schematic view of a T-shaped blank of the present invention.

Fig. 3 is a preform view of the present invention.

FIG. 4 is a diagram of a pre-forging of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without making any inventive effort are intended to fall within the scope of the present invention.

Various aspects of features of embodiments of the invention are described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details. The following description of the embodiments is merely for a better understanding of the invention by showing examples of the invention. The present invention is not limited to any particular arrangement and method provided below, but covers any modifications, substitutions, etc. of all product constructions, methods, and the like covered without departing from the spirit of the invention.

The invention provides a forming method of a titanium alloy inclined T-shaped die forging, which comprises the steps of freely forging a T-shaped rough blank, preforming, pre-forging, die forging and the like, and respectively strictly controlling heating temperature, heat preservation time, striking energy and pressing distance to obtain a forging with qualified filling performance as shown in figure 1.

The method comprises the steps of freely forging a T-shaped rough blank (shown in figure 2), preforming, pre-forging and heating at the same heating temperature in three links, forging and heating to 35 ℃ below a phase change point, wherein the heat preservation coefficient is calculated according to 0.6-0.8 mm/s, the die forging adopts a step heating mode, preheating and heating to 35 ℃ below the phase change point, the heat preservation coefficient is calculated according to 0.6-0.8 mm/s, heating to 15 ℃ above the phase change point after the preheating is finished, and the heat preservation coefficient is calculated according to 0.25-0.5 mm/s.

The forming method of the titanium alloy inclined T-shaped die forging comprises the following specific steps:

Firstly, designing a final forging die according to the outline dimension of a hot forging piece ((the outline dimension of a forging piece is x (the thermal shrinkage rate of a material) and designing a die matched with the shape of the final forging die), secondly, designing a die matched with the shape of the pre-forging die according to the outline dimension of the pre-forging piece, and determining the pre-forging die according to the outline dimension of the pre-forging piece and the equal-section equal-volume conversion design, so as to ensure that the pre-forging piece deforms uniformly when being forged to the final forging piece and the deformation is about 20% -35%, thirdly, designing the pre-forging die according to the outline dimension of the pre-forging piece, analyzing the structural characteristics of the pre-forging piece, determining the characteristic points (the characteristic points are connected into curved surfaces which divide the upper and lower volumes of the pre-forging piece uniformly) on the parting surfaces of the upper and lower dies, and sequentially connecting the starting points and the end points of the characteristic points to form a curve, wherein the curved surface formed by the curve is the curved parting surface of the die, and the pre-forging piece is the outline dimension of the die, and the pre-forging piece is determined according to the outline dimension of the pre-forging piece, and the equal-section equal-volume conversion design is ensured, and the deformation of the pre-forging piece is about 20% -50%;

Designing a T-shaped rough blank, wherein the appearance of a preformed piece is close to an inclined T shape, so that 5mm under-pressure and 30mm wide and 8mm deep burrs are added on the basis of the uniform cross section according to the appearance size of the preformed piece, the inclined T-shaped rough blank is obtained through equal volume conversion, and the production difficulty of the inclined T-shaped rough blank is high;

Step three, freely forging a T-shaped rough blank, namely heating a titanium alloy bar in an electric furnace to a standard temperature of 35 ℃ below a phase transition point, wherein the heat preservation time is calculated according to a heat preservation coefficient of 0.6-0.8 min/mm, the freely forging blank comprises two working steps of material dividing, drawing and shaping, the deformation is controlled within 20% -50%, and the final forging temperature is not lower than 820 ℃;

and step four, heating the blank to a deformation temperature, and preforming the T-shaped blank to obtain a preform (shown in figure 3).

Heating the T-shaped rough blank in an electric furnace, wherein the heating standard is that the temperature is 35 ℃ below the phase change point, the heat preservation time is calculated according to the heat preservation coefficient of 0.6-0.8 min/mm, the cavity is full of 2800T energy three hammers, the first hammer is tapped and positioned, the second hammer and the third hammer are respectively dried at intervals of 10 seconds, the mold is closed, the under-pressure of the forging piece is less than or equal to 5mm, and the final forging temperature is not lower than 820 ℃ to obtain the preformed piece.

And fifthly, heating the preformed piece to a deformation temperature, and performing pre-forging on the preformed piece to obtain a pre-forging piece (shown in figure 4). Heating the preformed piece in an electric furnace, wherein the heating standard is that the temperature is 35 ℃ below the phase transition point, the heat preservation time is calculated according to the heat preservation coefficient of 0.6-0.8 min/mm, the forging hammering times are 3 times, the hammering interval time is 15s, the hammering energy of the first hammer 2800t, the hammering energy of the second hammer 4000t, the hammering energy of the third hammer 5600t is forged until the mold is closed, the under-pressure of the forging piece is less than or equal to 5mm, and the final forging temperature is not lower than 820 ℃ to obtain the preformed piece.

And step six, heating the pre-forging piece to a deformation temperature, and forging by using a final forging die to obtain the die forging piece. Heating the pre-forging piece in an electric furnace according to the heating standard, wherein the temperature is 35 ℃ below the preheating phase change point, the heat preservation time is calculated according to the heat preservation coefficient of 0.6-0.8 min/mm, the temperature is heated to 15 ℃ above the phase change point after the preheating is finished, the heat preservation time is calculated according to the heat preservation coefficient of 0.25-0.5 min/mm, the forging hammering times are 3 times, the hammering interval time is 15s, the hammering energy of a 20mm thick base plate 2800t is used for a first hammer, the hammering energy of a 4000t is used for a 10mm thick base plate is used for a second hammer, the hammering energy of a third hammer is used for a die closure, the under-pressure of the forging piece is less than or equal to 5mm, and the final forging temperature is not lower than 820 ℃ to obtain the die forging piece.

Example 1

Firstly, designing a final forging die according to the outline dimension of a hot forging (see figure 1), designing a die matched with the shape of the hot forging (the outline dimension of the forging is x (1+material heat shrinkage rate)), secondly, designing a die matched with the shape of the pre-forging die according to the outline dimension of the pre-forging (see figure 4), designing a uniform deformation of the pre-forging when the pre-forging is forged to the final forging according to the outline dimension of the forging, and ensuring that the deformation is about 20% -35%, and thirdly, designing the pre-forging die according to the outline dimension of the pre-forging (see figure 4), designing a die matched with the shape of the pre-forging, analyzing the structural characteristics of the pre-forging, determining characteristic points (the upper and lower volume equally dividing of the pre-forging by the curved surface formed by connecting the characteristic points) of the pre-forging die parting surfaces, and sequentially connecting the starting point and the end point of the characteristic points to form a curve, wherein the curved surface formed by the curve is the curved parting surface of the die, and the outline dimension of the pre-forging die is determined according to the outline dimension of the pre-forging, and ensuring that the pre-forging is uniform in deformation when the pre-forging is about 20% -50% when the pre-forging is uniform in the outline dimension;

Designing a T-shaped rough blank (see figure 2), wherein the appearance of the preformed piece is close to an inclined T shape, so that 5mm under-pressure and 30mm wide and 8mm deep burrs are added on the basis of the equal section according to the appearance size of the preformed piece (figure 3), the inclined T-shaped rough blank is obtained through equal volume conversion, the production difficulty of the inclined T-shaped rough blank is high, the equal section of the inclined T-shaped rough blank is converted into the T-shaped rough blank, the T-shaped rough blank is preformed by rotating 90 degrees on the basis of a horizontal plane, the T-shaped rough blank is placed on a die for preforming, the T-shaped rough blank is guaranteed to be slowly and excessively deformed uniformly when being forged to the preformed piece, and the main deformation amount is 20% -50%, and the individual parts are 10% -15%;

And thirdly, determining a blanking specification phi 250 multiplied by 300mm according to the size of the titanium alloy oblique T-shaped rough blank. Heating the bar stock to 934 ℃ (the phase change point 969 ℃ of the batch of materials) for heat preservation, wherein the heat preservation time is 180min, the heat preservation coefficient is 0.7min/mm, discharging and forging the T-shaped rough blank, the method comprises two working steps of material dividing, drawing and shaping, the deformation is controlled within 20% -50%, and the final forging temperature is measured to 832 ℃;

Heating the T-shaped rough blank to 934 ℃ (969 ℃ of the phase change point of the material of the batch) for heat preservation, wherein the heat preservation time is 130min, the heat preservation coefficient is 0.7min/mm, discharging the material to perform preforming on the T-shaped rough blank, filling a cavity with 2800T energy three hammers, positioning the first hammer by tapping, respectively spacing 10s of a second hammer and a third hammer, closing the mould, and actually measuring 191 vertical dimension of a forging piece, wherein the final forging temperature is actually measured to 866 ℃ to obtain a preformed piece;

fifthly, heating the preformed piece to 934 ℃ which is the phase change point 969 ℃ of the material in the batch, preserving the heat for 100min, and carrying out pre-forging on the preformed piece by discharging from a furnace, wherein the forging and hammering times are 3 times, the hammering interval time is 15s, the hammering energy of a first hammer 2800t, the hammering energy of a second hammer 4000t and the hammering energy of a third hammer 5600t are forged until a mold is closed, and the vertical dimension of a forge piece is 90 and 90 in actual measurement;

Preheating the pre-forging piece to the temperature of 934 ℃ and preserving heat for 90min, wherein the heat preservation coefficient is 0.7min/mm, heating to 984 ℃ after the preheating is finished, preserving heat for 50min, the heat preservation coefficient is 0.3min/mm, the forging and hammering times are 3 times, the hammering interval time is 15s, the hammering energy of a 20mm thick backing plate 2800t is used for the first hammer, the hammering energy of a 4000t of a 10mm thick backing plate is used for the second hammer, the hammering energy of a 5600t backing plate is used for the third hammer, the vertical dimension of the forging piece is 55 actual measurement 57, and the final forging temperature is 872 ℃ to obtain the die forging piece.

And checking and accepting the forging according to the technical condition requirements, and filling the forging with good size and qualified performance after physicochemical treatment.

It should be noted that the above embodiments are only for illustrating the technical solution of the present invention, but the scope of the present invention is not limited thereto, and any equivalent modifications or substitutions can be easily made by those skilled in the art within the technical scope of the present invention, and these modifications or substitutions should be included in the scope of the present invention.

Claims (6)

1. A method for forging a titanium alloy oblique T-shaped forging, the method comprising the steps of:

heating the titanium alloy bar to a deformation temperature, and freely forging to obtain a T-shaped rough blank;

Heating a T-shaped blank to a deformation temperature, rotating the T-shaped blank by 90 degrees on the basis of a horizontal plane, placing the T-shaped blank in a pre-forming die, forging the pre-forming die to obtain a pre-forming piece, wherein the pre-forming piece comprises an inclined boss and a bottom plate, the inclined boss protrudes downwards from the middle section of the bottom plate, and the inclined boss occupies at least 3/4 of the space of the middle section;

Heating the preformed piece to a deformation temperature, and forging by using a pre-forging die to obtain a pre-forging piece;

heating the pre-forging piece to a deformation temperature, and forging by using a final forging die to obtain a die forging piece;

heating the titanium alloy bar to a deformation temperature, and before free forging the blank to obtain a T-shaped rough blank, further comprising:

designing matched dies according to the outline dimension of the die forging, wherein the dies comprise a preformed die, a pre-forging die and a final-forging die;

Designing a T-shaped blank according to the outline dimension of the preform;

for the preforming mould, according to die forging overall dimension design assorted mould, include:

Determining characteristic points of the preform on the parting surfaces of the upper die and the lower die according to the maximum cross section of the vertical preform;

Sequentially connecting the starting point and the end point of the characteristic points to form a curve, wherein the curve formed by the curve is a curve parting surface of the mold, so that the preformed piece can be uniformly divided up and down, and the preformed mold is determined according to the parting surface and the outline dimension of the preformed piece;

The preformed piece is designed according to the outline dimension of the preformed piece in an equal-section equal-volume conversion mode, the preformed piece is enabled to be uniformly deformed when being forged to the preformed piece, and the deformation is about 20% -50%;

designing a matched pre-forging die and a final-forging die according to the outline dimension of the die forging, comprising the following steps:

firstly, designing a final forging die matched with the die forging according to the outline dimension of the die forging;

the design of the pre-forging die is that the pre-forging die is matched with the pre-forging die in shape according to the outline dimension of the pre-forging die, wherein the pre-forging die is designed according to the outline dimension of the die forging die in an equal-section equal-volume conversion mode, and the pre-forging die is guaranteed to be uniformly deformed when being forged to the die forging die, and the deformation is about 20% -35%.

2. The method of claim 1, wherein the size of the final forging die is designed using a design formula that the size of the final forging die is equal to the forging external dimension x (1+ material heat shrinkage).

3. The method of claim 2, wherein designing the T-shaped blank based on the preform form factor comprises:

adding 5mm under-pressure and 30mm wide and 8mm deep burrs on the basis of the equal section according to the outline dimension of the preformed piece close to the inclined T shape, and performing equal volume conversion to obtain an inclined T-shaped rough blank;

and converting the inclined T-shaped rough blank into the T-shaped rough blank with the same cross section and the same volume.

4. A method according to claim 3, wherein the preforming process comprises:

Heating the T-shaped rough blank in an electric furnace, wherein the heating standard is that the temperature is 35 ℃ below the phase change point, and the heat preservation time is calculated according to the heat preservation coefficient of 0.6-0.8 min/mm;

placing the heated and insulated T-shaped rough blank into a pre-forming die;

And hammering the pre-forming die by using 2800T three hammers to enable the T-shaped rough blank to be full of the cavity, wherein the hammering interval time is 15s, the first hammer is used for tapping and positioning, the second hammer is used for hammering the three hammers until the die is closed, the forging under-pressure is less than or equal to 5mm, and the final forging temperature is not lower than 820 ℃ to obtain the pre-forming piece.

5. The method of claim 4, wherein the pre-forging process comprises:

Heating the preformed piece in an electric furnace, wherein the heating standard is that the temperature is 35 ℃ below the phase change point, and the heat preservation time is calculated according to the heat preservation coefficient of 0.6-0.8 min/mm;

Placing the heated and insulated preform into a pre-forging die;

Hammering the pre-forging die, wherein the forging hammering times are 3, the hammering interval time is 15s, the hammering energy of the first hammer 2800t, the hammering energy of the second hammer 4000t and the hammering energy of the third hammer 5600t are forged until the die is closed, the forging under-pressure is less than or equal to 5mm, and the final forging temperature is not lower than 820 ℃ to obtain the pre-forging.

6. The method of claim 5, wherein the finish forging process comprises:

Heating the pre-forging in an electric furnace, wherein the heating standard is that preheating is carried out at a temperature of 35 ℃ below a phase change point, the heat preservation time is calculated according to a heat preservation coefficient of 0.6-0.8 min/mm, the temperature is heated to 15 ℃ above the phase change point after the preheating is finished, and the heat preservation time is calculated according to a heat preservation coefficient of 0.25-0.5 min/mm;

Placing the heated and heat-preserving pre-forging piece into a final forging die;

And hammering the final forging die, wherein the forging times are 3, the hammering interval time is 15s, the first hammer is used for hammering energy of 20mm thick backing plates 2800t, the second hammer is used for hammering energy of 10mm thick backing plates 4000t, the third hammer is used for hammering energy of 5600t of backing plates until the die is closed, the under-pressure of the forging is less than or equal to 5mm, and the final forging temperature is not lower than 820 ℃ to obtain the die forging.