Cake-shaped forge piece and forging method thereof

Abstract

The invention relates to a cake-shaped forge piece and a forging method thereof, belongs to the technical field of forge piece forging, and solves the problem that a cake-shaped wheel disc forging method in the prior art cannot meet the flaw detection requirement of a high-performance wheel disc. The method comprises the steps that 1, a steel ingot or a blank is heated and subjected to heat preservation, and upsetting is conducted in the axial direction Z; 2, square drawing is conducted in the first radial direction Y, and then upsetting is conducted in the first radial direction Y; 3, square drawing is conducted in the second radial direction X, and then upsetting is conducted in the second radial direction X; 4, square drawing is conducted in the axial direction Z, and then upsetting is conducted in the axial direction Z; the first radial direction Y and the second radial direction X are perpendicular to the axial direction Z, and the first radial direction Y is perpendicular to the second radial direction X. The grain size of the cake-shaped forge piece prepared through the method is uniform and refined, the grain size can reach the 6.5 level, and the whole surface sensitivity 0.7 mm equivalent is detectable.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of forging technology of forgings, in particular to a pie-shaped forging and a forging method thereof. BACKGROUND

[0002] Gas turbines have the advantages of high thermal efficiency, less pollution, less water consumption, etc., and the gas turbine unit participating in combined cycle can achieve higher thermal efficiency. The gas turbine disc forging is the basis and guarantee condition for the design and manufacturing technology of advanced gas turbines, among which the compressor disc in the gas turbine is an alloy steel pie-shaped forging, which requires purity of composition, uniformity and refinement of grains, and ensures that the full surface of the flaw detection reaches 1.0mm of the detectable equivalent.

[0003] The existing forging process of the gas turbine compressor disc forging will cause mixed grains of the pie-shaped disc forging, and the full surface of the flaw detection reaches 1.6mm or even 1.2mm of the equivalent, which is the limit and cannot meet the requirements of high-performance discs. SUMMARY

[0004] In view of the above analysis, the embodiments of the present application aim to provide a pie-shaped forging and a forging method thereof to solve the problem that the existing pie-shaped disc forging method cannot meet the flaw detection requirements of high-performance discs.

[0005] In one aspect, the present application provides a forging method of a pie-shaped forging, the method comprising:

[0006] Step 1: heating a steel ingot or a blank and keeping warm, and upsetting along the axial direction Z;

[0007] Step 2: drawing square along the first radial direction Y, and then upsetting along the first radial direction Y;

[0008] Step 3: drawing square along the second radial direction X, and then upsetting along the second radial direction X;

[0009] Step 4: drawing square along the axial direction Z, and then upsetting along the axial direction Z;

[0010] The first radial direction Y and the second radial direction X are perpendicular to the axial direction Z, and the first radial direction Y is perpendicular to the second radial direction X.

[0011] Based on the further improvement of the above method, in steps 1 to 4, the temperature of the blank is always kept not lower than 800℃.

[0012] Based on the further improvement of the above method, in step 1, the temperature of the heating is 1200-1270℃.

[0013] Based on the further improvement of the above method, in step 3, before drawing square along the second radial direction X, the blank is returned to the furnace for the second heating.

[0014] Based on the further improvement of the above method, the temperature of the second heating is 1200-1270℃.

[0015] Based on the further improvement of the above method, in step 4, before upsetting along the axial direction Z, the blank is returned to the furnace for the third heating.

[0016] Based on the further improvement of the above method, the temperature of the third heating is 1200-1270℃.

[0017] Based on the further improvement of the above method, the blank is processed by octagonal pressing after each square drawing.

[0018] Based on the further improvement of the above method, the ingot or blank is cylindrical or prismatic.

[0019] In another aspect, the present application also provides a pie-shaped forged piece prepared by the above forging method.

[0020] Compared with the prior art, the present application can at least achieve one of the following beneficial effects:

[0021] 1. The present application adopts a "three-way upsetting and drawing" method for free forging, which is beneficial to improve the anisotropy of the forged piece, make the deformation of the entire forged piece uniform, fully refine the grains, and improve the homogenization of the forged piece, so as to meet the ultrasonic full-surface ultra-small equivalent detectability of the forged piece, and achieve a full-surface sensitivity of 0.7mm equivalent detectability.

[0022] 2. In the forging process of the present application, by limiting the total upsetting ratio and total drawing ratio of the blank in the axial direction Z, the first radial direction Y and the second radial direction X respectively, the grains are further refined and the ultrasonic full-surface detectable equivalent sensitivity is improved.

[0023] In the present application, the above technical solutions can also be combined with each other to realize more preferred combination schemes. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification or be understood by implementing the present application. The purpose and other advantages of the present application can be realized and obtained from the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0025] Figure 1 The figure is a forging process diagram of the pie-shaped forged piece of the present application.

[0026] Figure 2 The figure is a forging process diagram of the pie-shaped forged piece of the prior art single-direction (axial) upsetting and drawing forging.

[0027] Figure 3 The grain size photograph of the pie-shaped forging prepared for Example 1.

[0028] Figure 4 The grain size photograph of the pie-shaped forging prepared for Example 2.

[0029] Figure 5 The grain size photograph of the pie-shaped forging prepared for Comparative Example 1. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present application will be described in detail below with reference to the drawings, which form a part of this application, and together with the embodiments of the present application illustrate the principles of the present application, but not limit the scope of the present application.

[0031] The existing forging process of the gas turbine compressor wheel disc forging is a free forging process along a single direction (axial direction) twice upsetting and elongating (or three times single direction upsetting and elongating), opening and upsetting, and opening edge mode, specifically:

[0032] As shown in Figure 2 , the single direction (axial direction) upsetting and elongating process includes: reducing the height of the blank along the axial direction, then elongating along the axial direction to complete the first axial upsetting and elongating; continuing to upset the blank after axial elongation along the axial direction, then elongating along the axial direction to complete the second axial upsetting and elongating; continuing to upset the blank after axial elongation along the axial direction, then elongating along the axial direction to complete the third axial upsetting and elongating; finally, upsetting along the axial direction, and then opening the edge to form the finished product.

[0033] However, the existing single direction upsetting and elongating process will cause mixed grains in the pie-shaped wheel disc forging, and the full surface of the detection will reach 1.6mm or even 1.2mm equivalent, which is the limit, and cannot meet the requirements of high-performance wheel discs (1.0mm or less can be detected equivalent).

[0034] The present application provides a forging method for a pie-shaped forging, as shown in Figure 1 , the method comprises:

[0035] Step 1: heat the steel ingot or blank and keep warm, upset along the axial direction Z;

[0036] Step 2: elongate along the first radial direction Y, then upset along the first radial direction Y;

[0037] Step 3: elongate along the second radial direction X, then upset along the second radial direction X;

[0038] Step 4: elongate along the axial direction Z, then upset along the axial direction Z;

[0039] The first radial direction Y and the second radial direction X are perpendicular to the axial direction Z, and the first radial direction Y is perpendicular to the second radial direction X.

[0040] It should be noted that the axial direction Z is along the central axis of the ingot or the blank, and the first radial direction Y and the second radial direction X are along the diametric direction perpendicular to the axial direction Z.

[0041] Compared with the prior art, the present application adopts a "three-way upsetting and drawing" method (i.e., upsetting and drawing along the axial direction Z, the first radial direction Y and the second radial direction X, respectively) for free forging, which is beneficial to improve the anisotropy of the forged piece, make the deformation of the entire forged piece uniform, fully refine the grains, improve the homogenization of the forged piece, meet the ultrasonic full-surface super-small equivalent detectability of the forged piece, achieve a full-surface sensitivity of 0.7mm equivalent detectable, and meet the requirement that the full-surface sensitivity of the high-performance wheel disc shall not exceed 1.0mm.

[0042] Exemplarily, the ingot or the blank can be a cylinder or a prism.

[0043] If the ingot is a cylinder, the axial direction Z is along the central axis of the cylinder, and the first radial direction Y and the second radial direction X are along any two diametric directions perpendicular to each other on the cross section (circular section) of the cylinder; if the cylinder is a prism and the cross section is a rectangle, the axial direction Z is along the central axis of the prism, and the first radial direction Y and the second radial direction X are along the long side and the short side or the short side and the long side of the rectangular cross section, respectively.

[0044] In steps 1 to 4, the temperature of the blank is always kept not lower than 800℃. If the temperature of the blank drops to 800℃, the blank should be returned to the furnace for heating in time.

[0045] While ensuring the forging temperature, the number of forging fire times should not be too much, because too many forging fire times will lead to coarse grains. Therefore, by comprehensively considering the forging temperature and the number of forging fire times, a forging process with three fire times can be selected.

[0046] Exemplarily, in step 1, the temperature of the heating is 1200-1270℃.

[0047] Specifically, the ingot is heated to 1200-1270℃ in a heating furnace, and is kept for 20-30h, and then the blank is taken out and is upset along the axial direction Z (the height direction of the blank) on a large press; then the blank is drawn along the first radial direction Y, and then is upset along the first radial direction Y, to complete the first fire time forging.

[0048] Exemplarily, in step 3, before drawing along the second radial direction X, the blank is returned to the furnace for the second heating.

[0049] Exemplarily, the temperature of the second heating is 1200-1270℃.

[0050] Specifically, the billet after the first forging is reheated to 1200-1270℃, and kept for 20-30h, and then the billet is taken out and is drawn along the second radial direction X, and then is upset along the second radial direction X, and then is drawn along the axial direction Z, to complete the second forging.

[0051] Further, in step 4, before upsetting along the axial direction Z, the billet is reheated for the third time.

[0052] Exemplarily, the temperature of the third time of reheating is 1200-1270℃.

[0053] Specifically, the billet after the second forging is reheated to 1200-1270℃, and kept for 20-30h, and then the billet is taken out and is upset along the axial direction Z, to complete the third forging.

[0054] Further, after each time of drawing, the billet is processed to have an octagonal shape, which is beneficial to the uniform bulging of the billet at the corner part during the upsetting process.

[0055] Exemplarily, for the wheel disc forging, step 4 further comprises: after being upset along the axial direction Z to a certain height, the wheel disc forging is made to have a required height by rotating the edge of the forging using a strip-shaped hammer head, and finally, the wheel disc forging is manufactured after punching a hole in the center of the forging, rolling an outer circle, and flattening.

[0056] Specifically, the rotating edge using the strip-shaped hammer head comprises: the length of the strip-shaped hammer head is greater than the diameter of the forging, and the forging is rotated by an angle after each time of pressing the surface of the forging by the strip-shaped hammer head, until the height of the entire forging is pressed to the required height of the wheel disc forging.

[0057] Exemplarily, the height of each time of pressing of the strip-shaped hammer head is 90-110mm.

[0058] Exemplarily, the angle of each time of rotation of the forging is 15°-30°.

[0059] It should be noted that the height of the last pressing of the strip-shaped hammer head needs to be determined according to the target height of the forging.

[0060] Exemplarily, the punching of the hole in the center of the forging adopts a punch.

[0061] Exemplarily, the rolling of the outer circle comprises: the forging is vertically erected along the radial direction, and the outer surface of the forging is pressed to be circular by using a hammer head.

[0062] Since the height of the forging in the Z direction will be higher during the rolling of the outer circle, the flattening is to press the height of the forging after the rolling of the outer circle to the required height of the gas turbine compressor wheel disc forging, and the specific operation method of the flattening can be the same as that of the rotating edge.

[0063] Exemplarily, the total upsetting ratio of the ingot or the billet in the axial direction Z, the first radial direction Y and the second radial direction X is greater than 1.8, for example, 1.8-4, which is beneficial to the dynamic recrystallization of the forging blank, thereby further refining the grain and improving the ultrasonic full surface detectable equivalent sensitivity.

[0064] Exemplarily, the total upsetting ratio of the ingot or the billet in the axial direction Z, the first radial direction Y and the second radial direction X is greater than 1.8, for example, 1.8-4, which is beneficial to the dynamic recrystallization of the forging blank, thereby further refining the grain and improving the ultrasonic full surface detectable equivalent sensitivity.

[0065] It should be noted that if the temperature of the third fire billet drops below the final forging temperature (800℃), the forging cannot be completed in one fire, and the billet can be returned to the furnace for reheating, the heating temperature is 1100-1200℃, and the billet is taken out after a certain holding time for forging until the production of the forging is completed.

[0066] It should be noted that the distribution of forging fire times can be adjusted according to the actual temperature of the billet. For example, in the first fire, the temperature of the billet has dropped to the final forging temperature after being drawn in the first radial direction Y, and then the first radial direction Y upsetting in the original first fire can be performed in the second fire. In turn, the second radial direction X upsetting in the second fire can be performed in the third fire. Therefore, the total forging fire times will increase by one or two times. Therefore, the actual fire times can be determined according to the temperature of the billet on site. However, the more the fire times, the less the grain refinement, so the fire times should be reduced as much as possible under the condition of ensuring the temperature.

[0067] In a second aspect, the present application also provides a pie-shaped forging prepared by the above forging method.

[0068] The pie-shaped forging has an ultrasonic full surface sensitivity of 1.0mm or less equivalent detectable.

[0069] Further, the pie-shaped forging has a grain size of 6.5, and can achieve an ultrasonic full surface sensitivity of 0.7mm equivalent detectable.

[0070] Exemplarily, the pie-shaped forging is a wheel disc forging, which has a diameter of 1900-2100mm and a height of 300-400mm. The pie-shaped forging is an alloy steel containing nickel, chromium, molybdenum and vanadium elements.

[0071] In the following, the pie-shaped forging and the forging method thereof will be further described through specific examples.

[0072] In the following examples and comparative examples, the ultrasonic full surface detectable equivalent of the forging is detected by the equivalent method.

[0073] Example 1

[0074] The embodiment provides a pie-shaped wheel disc forging and a forging method thereof, and the forging is an alloy steel containing nickel, chromium, molybdenum and vanadium elements.

[0075] The forging method of the wheel disc forging, as shown in the figure, comprises the following steps. Figure 1

[0076] The first fire: a cylindrical steel ingot with a cross-sectional diameter of 1250 mm and a height H of 1200 mm is provided, the steel ingot is heated to 1250 DEG C in a heating furnace, and is kept for 25 h, the steel ingot is taken out and is upset along the axial direction Z by 900 mm on a large press; then the square mouth is drawn along the first radial direction Y by 900 mm, and an octagon is pressed, then the first radial direction Y is upset by 900 mm, and the first fire forging is completed.

[0077] The second fire: the blank after the first fire forging is returned to the furnace for the second heating to 1250 DEG C, and is kept for 25 h, the blank is taken out and the square mouth is drawn along the second radial direction X by 900 mm on the press, and an octagon is pressed, then the second radial direction X is upset by 900 mm, the square mouth is drawn along the axial direction Z by 900 mm, and an octagon is pressed, and the second fire forging is completed. At this time, the axial direction Z, the first radial direction Y and the second radial direction X of the blank are all completed by the upsetting and drawing process.

[0078] The third fire: the blank after the second fire forging is returned to the furnace for the third heating to 1250 DEG C, and is kept for 20 h, the blank is taken out and is upset along the axial direction Z by 750 mm on the press, and the third fire forging is completed. The target height is reached by the way of rotating the edge of the hammer head, the length of the strip-shaped hammer head is greater than the diameter of the forging, the forging is rotated by an angle every time the strip-shaped hammer head is pressed down on the surface of the forging, until the height of the entire forging is pressed to the required height of the gas turbine compressor wheel disc forging, the height of the strip-shaped hammer head is 100 mm every time, and the angle of the forging is 20 DEG every time. Finally, the wheel disc forging is manufactured after the center hole is punched, the outer circle is rolled and the surface is flattened.

[0079] The total upsetting ratio of the axial direction Z of the blank is 1200 ÷ 900 + 1770 ÷ 750 = 3.66, the total upsetting ratio of the first radial direction Y is 1800 ÷ 900 = 2, and the total upsetting ratio of the second radial direction X is 1770 ÷ 900 = 1.97.

[0080] The total drawing ratio of the axial direction Z of the blank is 1770 ÷ 1230 = 1.44, the total drawing ratio of the first radial direction Y is 1800 ÷ 1250 = 1.44, and the total drawing ratio of the second radial direction X is 1770 ÷ 1230 = 1.44.

[0081] The first radial direction Y and the second radial direction X are perpendicular to the axial direction Z, and the first radial direction Y is perpendicular to the second radial direction X.

[0082] The grain size photo of the wheel disc forging obtained in the embodiment 1 is as shown in the figure​Figure 3 As shown, the grain of the wheel disc forging is uniformly refined, the grain size is 7, and the ultrasonic flaw detection full surface detectable equivalent is 0.7mm of sensitivity.

[0083] Embodiment 2

[0084] The embodiment provides a pie-shaped wheel disc forging and a forging method thereof, and the forging is an alloy steel containing nickel, chromium, molybdenum and vanadium elements.

[0085] The forging method of the wheel disc forging, like Figure 1 As shown, comprises:

[0086] The first fire: a cylindrical steel ingot with a cross-sectional diameter of 1250mm and a height H of 1200mm is provided, the steel ingot is heated to 1200℃ in a heating furnace, and the blank is taken out after 30h of heat preservation, and is upset along the axial direction Z by 900mm on a large press; then it is drawn along the first radial direction Y to a square opening by 900mm, and is pressed into an octagon, and then is upset along the first radial direction Y by 900cm, to complete the first fire forging.

[0087] The second fire: the blank after the first fire forging is returned to the furnace for the second heating to 1200℃, and the blank is taken out after 30h of heat preservation, and is drawn along the second radial direction X to a square opening by 900mm on a press, and is pressed into an octagon, and then is upset along the second radial direction X by 900mm, and is drawn along the axial direction Z to a square opening by 900mm, and is pressed into an octagon, to complete the second fire forging. At this time, the blank in the axial direction Z, the first radial direction Y and the second radial direction X is completed by the upsetting and drawing process.

[0088] The third fire: the blank after the second fire forging is returned to the furnace for the third heating to 1200℃, and the blank is taken out after 30h of heat preservation, and is upset along the axial direction Z by 750mm on a press, to complete the third fire forging. The target height is achieved by the way of rotating the edge of the hammer head, the length of the strip-shaped hammer head is greater than the diameter of the forging, and the forging is rotated by an angle every time the strip-shaped hammer head is pressed down by one hammer, until the height of the entire forging is pressed to the required height of the gas turbine compressor wheel disc forging, the height of the strip-shaped hammer head is 100mm every time, and the angle of the forging is 25° every time. Finally, the manufacturing of the wheel disc forging is completed after the center hole is punched, the outer circle is rolled and the surface is flattened.

[0089] Wherein, the first radial direction Y and the second radial direction X are perpendicular to the axial direction Z, and the first radial direction Y is perpendicular to the second radial direction X.

[0090] The grain size photo of the wheel disc forging obtained in Embodiment 2 is shown in Figure 4 As shown, the grain is uniformly refined, the grain size is 6.5, and the grain size consistency is good; the ultrasonic full surface detectable equivalent detection is carried out, and the result is that the ultrasonic full surface detectable equivalent of the wheel disc forging is 0.7mm of sensitivity.

[0091] Embodiment 3

[0092] The embodiment provides a cake-shaped wheel disc forging and a forging method thereof, and the forging is an alloy steel containing nickel, chromium, molybdenum and vanadium elements.

[0093] The forging method of the wheel disc forging, as shown in the figure, comprises the following steps. Figure 1

[0094] First fire: a cylindrical steel ingot with a cross-sectional diameter of 1250 mm and a height H of 1200 mm is provided, the steel ingot is heated to 1270 DEG C in a heating furnace, and the blank is taken out after 20 h of heat preservation, and is upset along the axial direction Z by 900 mm on a large press; then the blank is drawn along the first radial direction Y by 900 mm, and is pressed into an octagon, and then is upset along the first radial direction Y by 900 mm, and the first fire forging is completed.

[0095] Second fire: the blank after the first fire forging is returned to the furnace for the second heating to 1270 DEG C, and the blank is taken out after 20 h of heat preservation, and is drawn along the second radial direction X by 900 mm on the press, and is pressed into an octagon, and then is upset along the second radial direction X by 900 mm, and is drawn along the axial direction Z by 900 mm, and is pressed into an octagon, and the second fire forging is completed. At this time, the blank is subjected to the upsetting and drawing process in the axial direction Z, the first radial direction Y and the second radial direction X.

[0096] Third fire: the blank after the second fire forging is returned to the furnace for the third heating to 1270 DEG C, and the blank is taken out after 20 h of heat preservation, and is upset along the axial direction Z by 750 mm on the press, and the third fire forging is completed. The target height is achieved by the way of rotating the edge of the hammer head, the length of the strip-shaped hammer head is greater than the diameter of the forging, the forging is rotated by an angle every time the strip-shaped hammer head is pressed down on the surface of the forging, until the height of the entire forging is pressed to the required height of the gas turbine compressor wheel disc forging, the height of the strip-shaped hammer head is 100 mm every time, and the angle of the forging is 30 DEG every time. Finally, the wheel disc forging is manufactured after the center hole is punched, the outer circle is rolled and the surface is flattened.

[0097] The first radial direction Y and the second radial direction X are perpendicular to the axial direction Z.

[0098] The wheel disc forging obtained in Embodiment 3 has uniform and refined grains, the grain size is 6.5, and the grain size consistency is good; the ultrasonic full-surface detectable equivalent detection is performed, and the result is that the ultrasonic full-surface detectable equivalent of the wheel disc forging is 0.7 mm of sensitivity.

[0099] Embodiment 4

[0100] ​The embodiment provides a pie-shaped wheel disc forging and a forging method thereof, the method is similar to that in the embodiment 1, and the difference is that the total upsetting ratios of the blank in the axial direction Z, the first radial direction Y and the second radial direction X are all less than 1.8, the total upsetting ratio of the blank in the axial direction Z is 1.75, the total upsetting ratio of the blank in the first radial direction Y is 1.5, and the total upsetting ratio of the blank in the second radial direction X is 1.5.

[0101] The wheel disc forging obtained in the embodiment 4 is of the grain size 6, and the ultrasonic full-surface detectable equivalent detection is performed, and the result is that the ultrasonic full-surface detectable equivalent of the wheel disc forging is 1.0 mm of sensitivity.

[0102] Embodiment 5

[0103] The embodiment provides a pie-shaped wheel disc forging and a forging method thereof, the method is similar to that in the embodiment 1, and the difference is that the total upsetting ratios of the blank in the axial direction Z, the first radial direction Y and the second radial direction X are all less than 1.8, the total upsetting ratio of the blank in the axial direction Z is 1.75, the total upsetting ratio of the blank in the first radial direction Y is 1.5, and the total upsetting ratio of the blank in the second radial direction X is 1.5.

[0104] The wheel disc forging obtained in the embodiment 5 is of the grain size 6, and the ultrasonic full-surface detectable equivalent detection is performed, and the result is that the ultrasonic full-surface detectable equivalent of the wheel disc forging is 1.0 mm of sensitivity.

[0105] Comparative example 1

[0106] The comparative example provides a pie-shaped wheel disc forging and a forging method thereof, the method is a one-way forging method, as shown in the formula (1), and the method comprises the following steps. Figure 2

[0107] First fire: a cylindrical steel ingot with a cross-sectional diameter of 1250 mm and a height H of 1200 mm is provided, the steel ingot is heated to 1270 DEG C in a heating furnace and kept for 20 h, the blank is taken out and is subjected to upsetting along the axial direction Z by 900 mm on a large press; then the blank is subjected to square hole drawing along the Z direction by 900 mm, and is pressed into an octagon, and the first fire forging is completed.

[0108] Second fire: the blank after the first fire is heated to 1270 DEG C in a heating furnace and kept for 20 h, then is subjected to upsetting along the Z direction by 900 mm, is subjected to square hole drawing along the axial direction Z by 900 mm and is pressed into an octagon, then is subjected to upsetting along the Z direction by 900 mm, is subjected to square hole drawing along the axial direction Z by 900 mm and is pressed into an octagon, and the second fire forging is completed. At this time, the axial direction Z of the blank is subjected to three times of upsetting and drawing.

[0109] ​The third heating: the billet after the second heating is heated to 1270℃, and kept for 20 hours. The billet is taken out and upset 750mm along the axial direction Z on the press to complete the third heating. The target height is reached by the way of hammer head rotation opening edge. Finally, the manufacturing of the wheel disc forging is completed by punching in the center of the forging, rolling the outer circle and flattening the edge.

[0110] The grain size photo of the wheel disc forging obtained by the comparative example 1 is shown in Figure 5 The uniformity is insufficient, the crystal is mixed, the minimum grain size is 7 levels, and the maximum grain size is 4 levels. The ultrasonic full surface detectable equivalent detection is carried out, and the result is that the ultrasonic full surface detectable equivalent of the wheel disc forging is 1.6mm of sensitivity.

[0111] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any change or replacement easily thought by the person skilled in the art within the technical range disclosed by the present application should be covered in the protection scope of the present application.

Claims

1. A method for forging a pancake-shaped forging, characterized in that: The method comprises: Step 1: Heat the steel ingot or billet and keep it warm, then upset it in the axial direction Z; Step 2: Squaring along the first radial direction Y, and then upsetting along the first radial direction Y; Step 3: Squaring along the second radial direction X, and then upsetting along the second radial direction X; Step 4: Square along the axial Z direction, and then upsetting along the axial Z direction; The first radial direction Y and the second radial direction X are respectively perpendicular to the axial direction Z, and the first radial direction Y is perpendicular to the second radial direction X.

2. The forging method according to claim 1, characterized in that In steps 1 to 4, the blank temperature is always maintained at not less than 800°C.

3. The forging method according to claim 2, characterized in that In step 1, the heating temperature is 1200-1270°C.

4. The forging method according to claim 2, characterized in that In step 3, before being squared along the second radial direction X, the blank is returned to the furnace for a second heating.

5. The forging method according to claim 4, characterized in that The temperature of the second heating is 1200-1270°C.

6. The forging method according to claim 2, characterized in that In step 4, the blank is returned to the furnace for a third heating before being upset in the axial Z direction.

7. The forging method according to claim 6, characterized in that The temperature of the third heating is 1200-1270°C.

8. The forging method according to claim 1, wherein: After each square drawing, the blank is pressed into an octagonal shape.

9. The forging method according to claim 1, wherein: The steel ingot or billet is cylindrical or prism.

10. A pancake-shaped forging produced according to the forging method according to any one of claims 1 to 9.

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