CN112139416A

CN112139416A - Preparation method and die of extra-large-size special-shaped ring forging with outer steps

Info

Publication number: CN112139416A
Application number: CN202010988156.0A
Authority: CN
Inventors: 董凯; 李兆银
Original assignee: Shanghai Electric Shmp Casting & Forging Co ltd
Current assignee: Shanghai Electric Shmp Casting & Forging Co ltd
Priority date: 2020-09-18
Filing date: 2020-09-18
Publication date: 2020-12-29
Anticipated expiration: 2040-09-18
Also published as: CN112139416B

Abstract

The invention discloses a preparation method of an extra-large-size special-shaped ring forging with an outer step, which comprises the following steps of: s1, preparing a blank, namely preparing a circular ring blank by adopting a steel ingot; s2 preforming, namely, placing the ring blank into a lower forming die, and extruding the ring blank into a preformed blank with a pre-outer step by using a pre-pressing male die, wherein the lower forming die comprises a cavity matched with the outer surface of a forging, the pre-pressing male die comprises an arc-shaped working surface, the outer ring wall of the ring blank is abutted against the inner wall of the cavity, and the inner ring wall of the ring blank is abutted against the working surface of the pre-pressing male die; and S3, final forming, namely, placing the preform in a lower forming die, and adopting an upper flat anvil to rotate and gradually press until the top end of the blank is horizontal and reaches the height requirement to form the final formed blank. The invention adopts the matching of the forming lower die, the prepressing convex die and the upper flat anvil to realize the formation of the outer step in an outward turning manner, thereby avoiding the condition that the body is influenced by the folding in the forming mode of upsetting and stripping the outer step, optimizing the forging process and improving the utilization rate of the forge piece.

Description

Preparation method and die of extra-large-size special-shaped ring forging with outer steps

Technical Field

The invention relates to the field of forging, in particular to a method for preparing an extra-large-size special-shaped ring forging with an external step and a die thereof.

Background

With the continuous development of ocean engineering in China, the demand for extra-large special-shaped forgings for maritime workers is increasing day by day. The replacing ring is a special-shaped ring extra-large marine equipment forging with an outer step, is used as one of core components of the marine hydraulic pile driver, and has a huge supporting effect on marine engineering project development.

The forging of the substitute ring has the advantages of complex shape, extremely large size and high flaw detection requirement, and the forging has high performance requirement due to severe use working condition environment. A few domestic enterprises have the production capacity of related marine ultra-large forgings, and the enterprises mainly depend on import before. Meanwhile, due to the fact that forging equipment is limited, production and manufacturing experience of super-huge forgings is lacked, process technology accumulation is insufficient, the utilization rate of the forgings is extremely low, the forgings belong to rough production, and the quality is not high, so that the method is a common problem faced by domestic super-huge forging manufacturing enterprises.

The forging ring is made of alloy structural steel 30Cr2Ni2Mo, the maximum outer diameter is 7200mm, the inner diameter is 4760mm, the total height is 1200mm, the outer step height is 300mm, the weight of the forging piece is 175.5 tons, and 300 ton-class electric furnace ingots are required for integral forging. Therefore, the main technical difficulties in their production are shaping and quality control. At present, the mode of upsetting and stripping the outer step is adopted to form a large-diameter excircle, the mode is very easy to fold at the excircle, and the mode is folded and expanded to the forging body when the mode is serious. Meanwhile, the 300T-grade electric furnace ingot belongs to an oversized ingot type, and in order to ensure the quality performance of a forged piece, a proper forging process is needed to forge the internal defects of the steel ingot, so that the flaw detection risk is reduced. Therefore, in view of the above problems, it is necessary to propose a further solution to solve at least one of the problems.

Disclosure of Invention

The invention aims to provide a preparation method of an extra-large-size special-shaped ring forging with an outer step, so as to overcome the defects in the prior art.

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

a preparation method of an extra-large-size special-shaped ring forging with an outer step comprises the following steps:

s1, making a blank,

preparing a circular ring blank by using a steel ingot;

the pre-forming at S2 is carried out,

placing a circular ring blank in a lower forming die, and extruding by using a pre-pressing male die to form a pre-formed blank with a pre-outer step, wherein the lower forming die comprises a cavity matched with the outer surface of the forging, the pre-pressing male die comprises an arc-shaped working surface, the outer ring wall of the circular ring blank is abutted against the inner wall of the cavity, and the inner ring wall of the circular ring blank is abutted against the working surface of the pre-pressing male die;

the final shape of the blank is S3,

and placing the preformed blank in a forming lower die, and adopting an upper flat anvil to rotate and gradually press until the top end of the blank is horizontal and meets the height requirement to form a final formed blank.

In a preferred embodiment of the invention, before step S1, step S0 of compacting is further included, and the ingot is subjected to upsetting-stretching-compacting-upsetting-stretching, wherein the upsetting ratio is not less than 2.3, the temperature of the ingot at upsetting is 1050 ℃ -1270 ℃, and the surface temperature of the ingot at compacting is 730 ℃ -800 ℃.

In a preferred embodiment of the invention, before step S0, the ingot is heated at 1220-1270 ℃ and kept for 33 +/-3 h.

In a preferred embodiment of the invention, in step S1, the steel ingot is heated at 1220-1270 ℃ and is treated after heat preservation for 20 +/-2 h.

In a preferred embodiment of the invention, in step S1, the upsetting height of the steel ingot is 1500-2000mm, and the upsetting ratio is not lower than 2.1.

In a preferred embodiment of the present invention, in step S1, a hollow punch is used to punch the hole, and after punching, the maximum wall thickness is close to the height, and a core rod is used to enlarge the hole, and the height is greater than or equal to 1900 mm.

In a preferred embodiment of the present invention, the ring blank obtained in step S1 is heated at 1220-1250 ℃, and is subjected to heat preservation for 13 ± 2h, and then step S2 is performed.

In a preferred embodiment of the invention, the heating speed is less than or equal to 40 ℃/h.

In a preferred embodiment of the present invention, in step S2, when the temperature of the annular preform is uniform, the pre-pressing male die presses the annular preform until an included angle is formed between a tangent of an inner wall of the pre-outer step of the preform and an axis of the pre-outer step.

In a preferred embodiment of the invention, the pressing amount of the pre-pressing male die is 850-.

In a preferred embodiment of the invention, when the temperature difference of the surface area of the circular ring blank is less than or equal to 50 ℃, the temperature of the circular ring blank is uniform.

In a preferred embodiment of the invention, the included angle is 35 ° to 45 °.

In a preferred embodiment of the present invention, in step S3, the upper flat anvil is 1200.

In a preferred embodiment of the invention, the upper flat anvil is pressed down by 80-120mm each time, and is rotated by 8-12 degrees each time.

In a preferred embodiment of the invention, the upper flat anvil is pressed by 100mm each time and is rotated by 10 degrees each time.

In a preferred embodiment of the present invention, the preform is heated at 1200-1240 ℃ and is processed after 12 + -2 h of heat preservation before step S3.

In a preferred embodiment of the present invention, the method further comprises a step S4 of performing a heat treatment after forging to austenitize the final-formed blank at 860 ℃ and 960 ℃.

The invention also provides a die for preparing the super-large-size special-shaped ring forging with the outer step, which comprises the following steps:

a forming lower die, which comprises a cavity matched with the outer surface of the forging,

the prepressing male die can move along the axis of the cavity, the prepressing male die comprises an arc-shaped working surface, and an included angle between the tangent line of the arc-shaped working surface and the axis of the prepressing male die is 35-45 degrees.

In a preferred embodiment of the invention, the device further comprises an upper flat anvil.

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

(1) the invention adopts the matching of the forming lower die, the prepressing convex die and the upper flat anvil to realize the formation of the outer step in the outward turning mode, avoids the condition that the body is influenced by the folding in the forming mode of upsetting and peeling the outer step, optimizes the forging process, improves the utilization rate of the forge piece, solves the forging production problem of the forge piece, and has important significance for realizing the localization of the forge piece, improving the manufacturing strength of large forge pieces and heavy equipment in China and promoting the ocean strategic development in China.

(2) According to the invention, the included angle between the tangent line of the inner wall of the pre-outer step and the axis of the pre-outer step is controlled, the radial deformation degree of the outer step is controlled, the radial rheology is balanced, and the forming effect is improved; further, when the included angle is 35-45 degrees, the radial deformation degree of the outer step is optimal, and the radial rheology is balanced, so that the requirements of final finished products can be met.

(3) According to the invention, through the compaction step and by adopting a high-temperature and large-deformation forging technology, columnar crystals are smashed, macro segregation is improved, as-cast structure is broken, and internal pores are welded, so that a forging blank with excellent internal quality is obtained, and the quality of a finished product forging is improved.

Drawings

FIG. 1 is a flow chart of a manufacturing process according to an embodiment of the present invention;

FIG. 2 is a flow chart of a manufacturing process according to another embodiment of the present invention;

fig. 3 is a schematic structural view of a 300-ton ingot used in the present invention, wherein T denotes an ingot cap end and B denotes an ingot bottom end;

fig. 4 is a schematic structural view of the steel ingot after step S0;

fig. 5 is a schematic structural view of the ring blank obtained in step S1;

FIG. 6 is a schematic structural view of a pre-pressing male die;

FIG. 7 is a schematic structural view of a forming lower die, wherein x denotes a die size and has no other special meaning;

FIG. 8 is a schematic view of a preform in a lower mold for forming;

fig. 9 is a schematic structural view of a final formed billet, wherein p denotes a billet size, and no other special meaning exists.

Specifically, 100, prepressing a male die; 110. an arc-shaped working surface;

200. forming a lower die; 210. working surface one; 220. a second working surface; 230. and a third working surface.

Detailed Description

The disclosure may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the examples included therein. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control. The term "prepared from …" as used herein is synonymous with "comprising". The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

The conjunction "consisting of …" excludes any unspecified elements, steps or components. If used in a claim, the phrase is intended to claim as closed, meaning that it does not contain materials other than those described, except for the conventional impurities associated therewith. When the phrase "consisting of …" appears in a clause of the subject matter of the claims rather than immediately after the subject matter, it defines only the elements described in the clause; other elements are not excluded from the claims as a whole.

When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted to include the ranges "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.

The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. "optional" or "any" means that the subsequently described event or events may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

Approximating language, as used herein throughout the specification and claims, is intended to modify a quantity, such that the invention is not limited to the specific quantity, but includes portions that are literally received for modification without substantial change in the basic function to which the invention is related. Accordingly, the use of "about" to modify a numerical value means that the invention is not limited to the precise value. In some instances, the approximating language may correspond to the precision of an instrument for measuring the value. In the present description and claims, range limitations may be combined and/or interchanged, including all sub-ranges contained therein if not otherwise stated.

In addition, the indefinite articles "a" and "an" preceding an element or component of the invention are not intended to limit the number requirement (i.e., the number of occurrences) of the element or component. Thus, "a" or "an" should be read to include one or at least one, and the singular form of an element or component also includes the plural unless the stated number clearly indicates that the singular form is intended.

Example 1:

as shown in fig. 1, a method for preparing an extra-large-size special-shaped ring forging with an outer step comprises the following steps:

s1, making a blank,

a circular ring blank is manufactured by adopting a steel ingot, and the shape of the circular ring blank is shown in figure 5.

In this step, it should be noted that the ring blank obtained needs to have good roundness.

Specifically, the steel ingot is placed in a heating furnace for heating and heat preservation at the temperature of 1220-1270 ℃, and is discharged after heat preservation for 20 +/-2 hours, so that the steel ingot has good fluidity and is beneficial to forging deformation. As shown in FIG. 4, the upset H is about 1500-2000mm, preferably about 1800mm, and the upset ratio is not less than 2.1. Returning to the furnace after upsetting, heating and preserving heat at 1220-1270 ℃, keeping the temperature for 13 +/-2 hours, taking the product out of the furnace, punching by using a hollow punch, preferably a phi 1450 hollow punch, controlling the ratio of the wall thickness to the height when the d is about 1450mm, and punching the maximum wallThe thickness and the height are similar, namely (D-D) ≈ 2H, so as to avoid the phenomenon of 'waisting', namely the phenomenon that the end surface has large size and the diameter at the height of 1/2 is small. The defects of surface cracks and the like of the forging stock need to be cleaned in time before reaming, and a core rod, preferably a phi 1200 core rod, is adopted during reaming and is assisted with a rounding process so as to ensure the roundness of the ring stock. The outline schematic diagram after reaming is shown in figure 5, namely a circular ring blank H₁The size is not limited to be more than 1900mm, the unilateral wall thickness is about 500mm, and the inner diameter is about 4760mm, and the size is set according to the size of a finished forging ring, namely the inner diameter of a circular ring blank is basically consistent with the inner diameter of a final forming forging (final forming blank), and the outer diameter of the large end of the preform is more than or equal to (the outer diameter of the circular ring blank plus the outer diameter of the large end of the forging)/2.

The pre-forming at S2 is carried out,

the annular blank is placed in the lower forming die 200, and the pre-pressing male die 100 is used for extrusion forming of the preform with the pre-outer step, and the preform and the lower forming die 200 are shown in fig. 8. The forming lower die 200 is matched with the prepressing convex die 100 and the upper flat anvil to form the outer step in an outward turning mode, so that the condition that the body is influenced by folding in an upsetting outer step forming mode is avoided, the forging process is optimized, the utilization rate of the forge piece is improved, the forging production difficulty of the forge piece is solved, and the forming method has important significance for realizing the localization of the forge piece, improving the manufacturing strength of large forge pieces and heavy equipment in China and promoting the ocean strategic development in China.

The forming lower die 200 comprises a cavity matched with the outer surface of the forging piece, the prepressing male die 100 comprises an arc-shaped working surface 110, the outer annular wall of the annular blank is abutted against the inner wall of the cavity, and the inner annular wall of the annular blank is abutted against the working surface of the prepressing male die 100.

As shown in fig. 6 and 7, the forming die 200 includes a cavity that matches the outer surface of the forging. In this embodiment, the cavity of the lower forming die 200 is matched with the shape of the substitute knock-out ring, that is, the working surface of the cavity of the lower forming die 200 sequentially includes a first vertical working surface 210, a second working surface 220 forming an arc-shaped curved surface, and a third vertical working surface 230. The prepressing punch 100 comprises an arc-shaped working surface 110, and preferably, an included angle between a tangent line of the arc-shaped working surface 110 and an axis of the prepressing punch 100 is 35-45 degrees, so that the radial deformation degree of the outer step is optimal, and the radial rheology is balanced. The pre-pressing punch 100 is movable along the axis of the cavity to press and outwardly support the annular preform placed in the lower forming die 200 to form a preform as shown in fig. 8. When the included angle is small, the radial rheological property of the outer step is insufficient, and the outer diameter size of the large end of the forge piece is difficult to achieve; when the angle is too large, the radial flow of the outer step is too large, and the condition that the size of the inner diameter of the large end of the forge piece is large to cause the size of the forge piece to be in a shortage state easily occurs.

Specifically, the ring blank is put into a furnace and heated to 1220-1250 ℃, and is discharged after heat preservation for 13 +/-2 hours. The heating needs to be controlled at a heating speed of less than or equal to 40 ℃/h, the phenomenon that local temperature difference is too large due to rapid heating is avoided, secondly, the blank is placed reasonably, particularly, the position of the blank in the furnace needs to be noticed, a nozzle or flame in the furnace is kept away from the position as far as possible, the condition of local high temperature is avoided, and therefore the circular blank is uniformly heated, and local extrusion deformation in the following steps is avoided.

The processed ring blank is placed in a forming lower die 200, after the temperature of the ring blank is observed and measured to be uniform, the temperature difference of different areas on the surface is generally less than or equal to 50 ℃, the ring blank is promoted to generate forging rheology in the forming lower die 200 and the pre-pressing male die 100 by downward movement of the pre-pressing male die 100, the general pressing amount is 850 plus 950mm, a pre-forming blank is formed, the tangent line of the inner wall of the pre-outer step of the pre-forming blank forms an included angle with the axial line thereof, the included angle alpha is preferably 35-45 degrees, and the shape of the included angle alpha is shown in figure 8. If the temperature difference of the ring blank is too large, the forging rheological trends at different temperatures are different, so that an ellipse is easy to appear, and when the temperature difference of the surface area is less than or equal to 50 ℃, the metal rheological difference caused by the temperature is very small, so that the obvious forging rheological difference cannot appear.

The final shape of the blank is S3,

the preform is placed in the lower forming die 200 and rotated and progressively pressed using the upper flat anvil until the top of the preform is level and reaches the desired height to form the final preform, which is shown in fig. 9.

Specifically, the preform is placed in a heating furnace for heating and heat preservation at 1200-1240 ℃, and is taken out after heat preservation for 12 +/-2 hours. Considering the actual blank thickness, it is preferable to use a flat anvil with a width of 1200, and by rotating and pressing gradually, the outer step flows outwards in an everted manner, the inner wall of the outer step flows inwards in a pressed manner, each time the outer step is pressed by 80-120mm, each time the outer step is rotated by 8-12 degrees, in this embodiment the outer step is pressed by about 100mm, each time the outer step is rotated by about 10 degrees, and the outer step is pressed to a blank height of 1200mm to form a final formed blank, and the outline of the final formed blank is schematically shown in fig. 9.

Example 2:

as shown in fig. 2, before step S1, step S0 of compacting is further included. Because the size of the forging ring forging is large, 300-ton ultra-large electric furnace ingot is needed, in order to reduce the quality risk brought by metallurgical defects, in the compaction step, the whole large upsetting ratio and the wide anvil are combined, a three-upsetting three-drawing two-time compaction mode is adopted, coarse grains in the steel ingot are quickly refined, and the defects in the large steel ingot are welded, namely, upsetting-drawing is a cycle, the aim is to crush the grains axially and radially, and the compaction operation is carried out after each drawing to further compact the core structure.

Specifically, the steel ingot is subjected to upsetting-stretching-compacting-upsetting-stretching. Wherein, the upsetting ratio is more than or equal to 2.3, and when the upsetting ratio is less than 2.3, the effect of crushing crystal grains is difficult to achieve, and the axial large crystal grains are easy to appear. The blank temperature is 1050 ℃ -1270 ℃ during upsetting, the temperature is lower, the upsetting deformation resistance is large, the upsetting of a press is not moved, the temperature is too high, the heating furnace is difficult to reach the temperature, and the hot crack is easy to occur. Pressing the surface temperature of the blank in real time to be 730-800 ℃, and keeping the blank in the pressing state at a low temperature; the temperature is high, the deformation is mainly concentrated on the surface, the pressing through is difficult, and the core cannot be deformed.

Further preferably, the steel ingot is heated at 1220 ℃ -1270 ℃ and is kept warm for 33 +/-3 h before step S0. Through the compaction step, a high-temperature and large-deformation forging technology is adopted, columnar crystals are smashed, macro segregation is improved, as-cast structure is broken, internal pores are welded, a forging blank with excellent internal quality is obtained, and the quality of finished products of forgings is improved.

Specifically, the steel ingot is gradually pressed and pressed, the steel ingot shown in figure 3 is cut and tapped, and then the steel ingot is placed in a heating furnace for heating and heat preservation at the temperature of 1220-1270 ℃, and the heat preservation is carried out for 33 +/-3 hours. In order to facilitate field operation, the bottom clamp handle is pressed after the steel ingot is taken out of the furnace, then square drawing and chamfering are carried out, compaction is carried out when the surface temperature is cooled to 730-800 ℃, then upsetting and drawing-out are carried out twice to achieve the effect of compacting the blank, and the temperature of the forging stock is kept within the range of 1050-1270 ℃ all the time in the upsetting process.

The other steps are substantially the same as in example 1.

In a preferred embodiment of the present invention, the method further comprises a step S4 of heat treatment after forging, in which the final formed blank is austenitized at 860 ℃ and 960 ℃ to obtain a forging blank with uniform internal structure and a shape conforming to the size requirement of the forging.

As shown in fig. 6 and 7, the invention also provides a die for preparing the super-large-size special-shaped ring forging with the outer step, which comprises a forming lower die 200 and a pre-pressing convex die 100.

Specifically, the forming lower die 200 includes a cavity matched with the outer surface of the forging, that is, the cavity working surface of the forming lower die 200 sequentially includes a first vertical working surface 210, a second working surface 220 forming an arc-shaped curved surface, and a third vertical working surface 230, so as to be the same as the forging, that is, the shape of the forging ring. The prepressing male die 100 can move along the axis of the cavity, the prepressing male die 100 comprises an arc-shaped working surface 110, and the included angle between the tangent line of the arc-shaped working surface 110 and the axis of the prepressing male die 100 is 35-45 degrees. In this embodiment, the pre-pressing punch 100 is a rotary body, and the arc-shaped working surface 110 is an arc-shaped annular working surface.

In conclusion, the invention adopts the matching of the lower forming die, the prepressing convex die and the upper flat anvil to realize the formation of the outer step in the outward turning mode, avoids the condition that the body is influenced by the folding of the outer step forming mode of upsetting and peeling, optimizes the forging process, improves the utilization rate of the forge piece, solves the forging production problem of the forge piece, and has important significance for realizing the localization of the forge piece, improving the manufacturing strength of large forge pieces and heavy equipment in China and promoting the ocean strategic development in China.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. The preparation method of the extra-large-size special-shaped ring forging with the outer steps is characterized by comprising the following steps of:

s1, making a blank,

preparing a circular ring blank by using a steel ingot;

the pre-forming at S2 is carried out,

the final shape of the blank is S3,

2. The method for preparing the extra-large-size special-shaped ring forging with the outer step is characterized by further comprising the step S0 of compacting before the step S1,

upsetting, stretching, compacting, upsetting and stretching steel ingots, wherein the upsetting ratio is more than or equal to 2.3, the blank temperature is 1050-1270 ℃ during upsetting, and the blank surface temperature is 730-800 ℃ during compacting.

3. The method for preparing the extra-large-size special-shaped ring forging with the outer step according to claim 2, wherein before the step S0, the steel ingot is heated at 1220-1270 ℃ and is kept warm for 33 +/-3 h.

4. The method for preparing the extra-large-size special-shaped ring forging with the outer step according to claim 1, wherein the steel ingot is heated at 1220-1270 ℃ in step S1, and is treated after heat preservation is carried out for 20 +/-2 hours.

5. The method for preparing the extra-large-size special-shaped ring forging with the outer step according to claim 1, wherein the ring blank prepared in the step S1 is heated at 1220-1250 ℃ and is subjected to heat preservation for 13 +/-2 hours, and then the step S2 is carried out.

6. The method for preparing the extra-large size profiled ring forging with outer step according to claim 1 or 5, characterized in that, in step S2, when the temperature of the ring blank is uniform, the pre-pressing male die presses the ring blank until the tangent line of the inner wall of the pre-outer step of the preform forms an included angle with the axis.

7. The method for manufacturing the extra-large-sized special-shaped ring forging with the outer step according to claim 6, wherein the included angle is 35-45 degrees.

8. The method for preparing the extra-large-size special-shaped ring forging with the outer step according to claim 1, wherein in the step S3, the upper flat anvil is 1200.

9. The method for preparing the extra-large-size special-shaped ring forging with the outer step according to claim 1, wherein the upper flat anvil is pressed down by 80-120mm each time, and the angle of rotation is 8-12 degrees each time.

10. The utility model provides a mould for preparing outband step super large size dysmorphism ring forging which characterized in that includes: