Special-shaped martensitic stainless steel forge piece and forming and manufacturing method thereof

Abstract

The invention provides a special-shaped martensitic stainless steel forge piece and a forming and manufacturing method thereof.The forming and manufacturing method comprises the steps that (1) after an electroslag ingot is subjected to upsetting and drawing treatment, punching treatment and chambering treatment in sequence, a blank with the annular section is obtained; (2) the annular-section blank is placed in a tire mold to be extruded and deformed, and an annular special-shaped prefabricated blank is obtained; and (3) the annular special-shaped prefabricated blank is placed in a ring rolling mill to be subjected to ring rolling treatment, and the special-shaped martensitic stainless steel forge piece is obtained. The ring rolling mill comprises a core roller, a main roller, an upper conical roller and a lower conical roller; a groove matched with the shape of the outer surface of the annular special-shaped preformed blank is formed in the outer surface of the main roller; the core roller is provided with a protruding structure matched with the inner surface of the annular special-shaped prefabricated blank in shape. By adopting the method provided by the invention, the utilization rate of the material can be effectively improved, and the processing period is shortened, so that batch production is realized; and the obtained forge piece can meet the requirements of product structure combination and performance.

Description

Technical Field

[0001] The invention belongs to the technical field of forging and forming, and relates to a special-shaped martensitic stainless steel forging, and in particular to a special-shaped martensitic stainless steel forging and a forming and manufacturing method thereof. Background Art

[0002] High-performance martensitic heat-resistant steel forgings are mainly used in aerospace and heavy-duty gas turbine fields, and are widely used in the manufacture of compressor turbine discs, air inlet casings, mounting edges and other devices. The ring rolling process, also known as hole expansion or ring rolling, is a continuous local shaping process that uses ring rolling equipment such as tire membrane forming and ring rolling machines to reduce wall thickness, expand diameter, and form cross-sectional profiles. The traditional ring rolling process is suitable for rectangular or nearly rectangular cross-section rings. For complex cross-section ring section forgings, a large amount of subsequent machining is required. Therefore, special-shaped ring rolling is the inevitable development direction of the ring rolling process.

[0003] At present, near-net-shape forming technology has been widely used in the manufacturing of ring forgings to realize the rolling forming of ring forgings with non-rectangular cross-sections such as internal special shapes, external special shapes, internal and external special shapes, and directly rolling out ring forgings with complex cross-sectional contours. It not only improves the utilization rate of materials, but also reduces the subsequent processing allowance and processing cycle. It has high technical and economic efficiency and is a very attractive research field and development direction in ring rolling technology.

[0004] However, the horizontal ring rolling technology used in near-net forming technology is still difficult to prepare special-shaped ring forgings. Special-shaped ring forgings are still mainly produced using rectangular section rolling technology. This process has a low material utilization rate and a long forging processing cycle when preparing end face special-shaped ring forgings. In addition, mechanical processing will also destroy the internal streamlines of the special-shaped rings, which will also have a certain impact on the service life of the special-shaped ring forgings.

[0005] In addition, although the rectangular rolling technology can produce ring forgings with special-shaped cross-sections that meet the technical requirements of the products, there is a certain gap between this process and the special-shaped forming technology, especially when producing cross-section ring forgings. The material utilization rate of this process is low and the forging processing cycle is long.

[0006] In summary, the material utilization rate of the special-shaped ring rolling process is effectively improved, the rolling efficiency is high, the production cost is low, the obtained rings are of high precision and small processing allowance, which can effectively improve the competitiveness of the products. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention aims to provide a special-shaped martensitic stainless steel forging and a forming and manufacturing method thereof. The method provided by the present invention reduces material loss, shortens the processing cycle, and through the design of the ring rolling machine, the prepared special-shaped martensitic stainless steel forging has higher precision.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a forming and manufacturing method for a special-shaped martensitic stainless steel forging, the forming and manufacturing method comprising the following steps:

[0010] (1) The electroslag ingot is subjected to upsetting treatment, punching treatment and hole expansion treatment in sequence to obtain a ring-shaped cross-section blank;

[0011] (2) placing the annular cross-section blank obtained in step (1) in a fetal membrane and extruding and deforming it to obtain an annular special-shaped preform;

[0012] (3) placing the annular special-shaped preform obtained in step (2) on a ring rolling machine for ring rolling to obtain the special-shaped martensitic stainless steel forging;

[0013] Step (3) The ring rolling mill comprises a core roll, a main roll, an upper tapered roll and a lower tapered roll; the outer surface of the main roll is provided with a groove matching the outer surface shape of the annular special-shaped preform;

[0014] The core roller has a convex structure matching the inner surface shape of the annular special-shaped preform.

[0015] The present invention can make the profiled surface of the annular special-shaped preform and the profiled working area of ​​the ring rolling machine cooperate well through the core roller, main roller, upper tapered roller and lower tapered roller used in the ring rolling process, and can effectively control the growth rate of the annular special-shaped preform, while allowing the preform to increase the sufficient deformation amount during the ring rolling process to ensure the requirements of the structure and performance of the obtained product; and the method can greatly improve the utilization rate of materials, shorten the processing cycle, and thus realize mass production.

[0016] As a preferred technical solution of the present invention, the upsetting treatment in step (1) includes three upsetting treatments and two lengthening treatments.

[0017] Preferably, the deformation amount of each upsetting treatment in step (1) is 40-50%, for example, it can be 40%, 42%, 44%, 46%, 48% or 50%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] It is worth noting that the hole expansion treatment in step (1) of the present invention also includes a regular flattening treatment of the forging.

[0019] As a preferred technical solution of the present invention, the fetal membrane in step (2) includes an outer mold and an inner mold.

[0020] As a preferred technical solution of the present invention, the specific preparation method of the annular special-shaped preform described in step (2) includes: subjecting the annular cross-section blank described in step (1) to heat preservation treatment, and then placing it in an outer mold, and placing the inner mold in the inner hole of the annular cross-section blank, and then using a press to press the inner mold into the annular cross-section blank.

[0021] As a preferred technical solution of the present invention, the temperature of the heat preservation treatment is 1150-1200°C, for example, it can be 1150°C, 1160°C, 1170°C, 1180°C, 1190°C or 1200°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] Preferably, the insulation time of the insulation treatment is 0.3-0.5 min / mm×effective thickness, wherein the specific value of 0.3-0.5 min / mm can be, for example, 0.3 min / mm, 0.34 min / mm, 0.38 min / mm, 0.42 min / mm, 0.46 min / mm or 0.5 min / mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] It is worth noting that the effective thickness described in the present invention is obtained by an equal volume conversion method.

[0024] As a preferred technical solution of the present invention, the difference between the outer diameter of the annular cross-section blank and the inner diameter of the outer mold is 12 to 18 mm, for example, it can be 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm or 18 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] Preferably, the height of the annular cross-section blank is 60 to 80 mm higher than the height of the annular special-shaped preform, for example, it can be 60 mm, 64 mm, 68 mm, 72 mm, 76 mm or 80 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] As a preferred technical solution of the present invention, the ring rolling process in step (3) includes: inserting the annular shaped preform in step (2) into the core roller and matching them with each other, matching the annular shaped preform with the groove on the outer surface of the main roller, fitting the upper tapered roller with the cross-section of the annular shaped preform, and then moving the core roller radially toward the main roller, the upper tapered roller and the lower tapered roller rotate respectively around their respective axis directions, and move radially away from the main roller, so that the ring wall of the annular shaped preform becomes thinner and the outer diameter increases, thereby obtaining the shaped martensitic stainless steel forging.

[0027] It is worth noting that in the ring rolling process described in step (3) of the present invention, the annular special-shaped preform described in step (2) is mainly subjected to the feed force given by the core roller and the downward pressure given by the upper cone roller, thereby realizing the ring rolling process of the blank.

[0028] As a preferred technical solution of the present invention, the feed speed of the core roller is 0.4-0.8 mm / s, for example, it can be 0.4 mm / s, 0.45 mm / s, 0.5 mm / s, 0.55 mm / s, 0.6 mm / s, 0.65 mm / s, 0.7 mm / s or 0.8 mm / s, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, the linear speed of the main roller is 1200-1500 mm / s, for example, it can be 1200 mm / s, 1250 mm / s, 1300 mm / s, 1350 mm / s, 1400 mm / s, 1450 mm / s or 1500 mm / s, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] As a preferred technical solution of the present invention, the pressing speeds of the upper tapered roller and the lower tapered roller are the same.

[0031] Preferably, the pressing speed of the upper and lower tapered rollers is 1 to 1.5 mm / s, for example, 1 mm / s, 1.1 mm / s, 1.2 mm / s, 1.3 mm / s, 1.4 mm / s or 1.5 mm / s, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0032] The present invention can further ensure the organization and performance requirements of the obtained product by optimizing the working parameters of the core roller, the main roller, the upper cone roller and the lower cone roller during the ring rolling process;

[0033] More specifically, if the feed speed of the core roller is too high, it will cause scabbing on the upper and lower end surfaces of the forging; if the linear speed of the main roller is too high, it will cause the forging to warp; if the pressing speed of the upper and lower tapered rollers is too high, it will cause roller climbing; if the working parameters of the core roller, main roller, upper tapered roller and lower tapered roller are too low, it will reduce production efficiency, thereby increasing production costs.

[0034] In a second aspect, the present invention provides a special-shaped martensitic stainless steel forging, wherein the special-shaped martensitic stainless steel forging is obtained by the forming and manufacturing method provided in the first aspect.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The method provided by the present invention can effectively improve the utilization rate of materials, shorten the processing cycle, and thus realize mass production;

[0037] (2) The method provided by the present invention can ensure that the obtained product meets the product requirements of organizational structure and performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a production flow chart of the special-shaped martensitic stainless steel forgings of the present invention;

[0039] Figure 2 It is a schematic diagram of the structure of the annular special-shaped preform of the present invention;

[0040] Figure 3 This is a schematic diagram of the principle of ring rolling of a special-shaped martensitic stainless steel forging according to the present invention;

[0041] Figure 4 is a schematic diagram of the outer mold in the fetal membrane of the present invention;

[0042] Figure 5 is a schematic diagram of the inner mold in the fetal membrane of the present invention;

[0043] Among them, 1 is the main roller, 2 is the lower tapered roller, 3 is the upper tapered roller, 4 is the core roller, and 5 is the annular special-shaped preform. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0045] As a specific embodiment, the present invention provides a special-shaped martensitic stainless steel forging, such as Figure 1 As shown, the forming and manufacturing method of the special-shaped martensitic stainless steel forging comprises the following steps:

[0046] (1) The electroslag ingot is subjected to three upsetting treatments, two drawing treatments, a punching treatment, and a hole expansion treatment in sequence to obtain a ring-shaped cross-section blank;

[0047] The deformation of each roughening and stretching treatment is 40-50%;

[0048] (2) The annular cross-section blank of step (1) is subjected to heat preservation treatment and then placed in a Figure 4 In the outer mold shown, Figure 5 The inner mold shown is placed in the inner hole of the annular cross-section blank, and then the inner mold is pressed into the annular cross-section blank by a press to obtain a Figure 2 The annular shaped preform shown;

[0049] The temperature of the heat preservation treatment is 1150-1200°C, and the heat preservation time is 0.3-0.5min / mm×effective thickness;

[0050] (3) placing the annular special-shaped preform obtained in step (2) on a ring rolling machine for ring rolling to obtain the special-shaped martensitic stainless steel forging;

[0051] Step (3) The ring rolling mill comprises a core roll 4, a main roll 1, an upper tapered roll 3 and a lower tapered roll 2; the outer surface of the main roll 1 is provided with a groove matching the outer surface shape of the annular special-shaped preform 5;

[0052] The core roller 4 has a convex structure matching the inner surface shape of the annular special-shaped preform 5;

[0053] like Figure 3 As shown, the ring rolling process includes: inserting the annular shaped preform 5 of step (2) into the core roller 4 and matching them with each other, matching the annular shaped preform 5 with the groove on the outer surface of the main roller 1, fitting the upper tapered roller 3 with the cross section of the annular shaped preform 5, and then moving the core roller 4 radially toward the main roller 1, and the upper tapered roller 3 and the lower tapered roller 2 respectively rotate around their respective axis directions and move radially away from the main roller 1, so that the ring wall of the annular shaped preform 5 becomes thinner and the outer diameter increases, thereby obtaining the shaped martensitic stainless steel forging;

[0054] The feeding speed of the core roller is 0.4-0.8 mm / s, the linear speed of the main roller is 1200-1500 mm / s, and the pressing speeds of the upper tapered roller and the lower tapered roller are the same, which is 1-1.5 mm / s.

[0055] Example 1

[0056] This embodiment provides a special-shaped martensitic stainless steel forging, such as Figure 1 As shown, the forming and manufacturing method of the special-shaped martensitic stainless steel forging comprises the following steps:

[0057] (1) The electroslag ingot is subjected to three upsetting treatments, two drawing treatments, a punching treatment, and a hole expansion treatment in sequence to obtain a ring-shaped cross-section blank;

[0058] The deformation amount of each roughening and stretching treatment is 45%;

[0059] (2) The annular cross-section blank of step (1) is subjected to heat preservation treatment and then placed in a Figure 4 In the outer mold shown, Figure 5 The inner mold shown is placed in the inner hole of the annular cross-section blank, and then the inner mold is pressed into the annular cross-section blank by a press to obtain a Figure 2 The annular shaped preform shown;

[0060] The temperature of the heat preservation treatment is 1175°C, and the heat preservation time is 0.4min / mm×effective thickness;

[0061] (3) placing the annular special-shaped preform obtained in step (2) on a ring rolling machine for ring rolling to obtain the special-shaped martensitic stainless steel forging;

[0062] Step (3) The ring rolling mill comprises a core roll 4, a main roll 1, an upper tapered roll 3 and a lower tapered roll 2; the outer surface of the main roll 1 is provided with a groove matching the outer surface shape of the annular special-shaped preform 5;

[0063] The core roller 4 has a convex structure matching the inner surface shape of the annular special-shaped preform 5;

[0064] like Figure 3 As shown, the ring rolling process includes: inserting the annular shaped preform 5 of step (2) into the core roller 4 and matching them with each other, matching the annular shaped preform 5 with the groove on the outer surface of the main roller 1, fitting the upper tapered roller 3 with the cross section of the annular shaped preform 5, and then moving the core roller 4 radially toward the main roller 1, and the upper tapered roller 3 and the lower tapered roller 2 respectively rotate around their respective axis directions and move radially away from the main roller 1, so that the ring wall of the annular shaped preform 5 becomes thinner and the outer diameter increases, thereby obtaining the shaped martensitic stainless steel forging;

[0065] The feeding speed of the core roller is 0.6 mm / s, the linear speed of the main roller is 1350 mm / s, and the pressing speeds of the upper and lower tapered rollers are the same, which is 1.25 mm / s.

[0066] Example 2

[0067] This embodiment provides a special-shaped martensitic stainless steel forging, such as Figure 1 As shown, the forming and manufacturing method of the special-shaped martensitic stainless steel forging comprises the following steps:

[0068] (1) The electroslag ingot is subjected to three upsetting treatments, two drawing treatments, a punching treatment, and a hole expansion treatment in sequence to obtain a ring-shaped cross-section blank;

[0069] The deformation amount of each roughening and stretching treatment is 40%;

[0070] (2) The annular cross-section blank of step (1) is subjected to heat preservation treatment and then placed in a Figure 4 In the outer mold shown, Figure 5 The inner mold shown is placed in the inner hole of the annular cross-section blank, and then the inner mold is pressed into the annular cross-section blank by a press to obtain a Figure 2 The annular shaped preform shown in the figure; the temperature of the heat preservation treatment is 1150°C, and the heat preservation time is 0.5min / mm×effective thickness;

[0071] (3) placing the annular special-shaped preform obtained in step (2) on a ring rolling machine for ring rolling to obtain the special-shaped martensitic stainless steel forging;

[0072] Step (3) The ring rolling mill comprises a core roll 4, a main roll 1, an upper tapered roll 3 and a lower tapered roll 2; the outer surface of the main roll 1 is provided with a groove matching the outer surface shape of the annular special-shaped preform 5;

[0073] The core roller 4 has a convex structure matching the inner surface shape of the annular special-shaped preform 5;

[0074] like Figure 3 As shown, the ring rolling process includes: inserting the annular shaped preform 5 of step (2) into the core roller 4 and matching them with each other, matching the annular shaped preform 5 with the groove on the outer surface of the main roller 1, fitting the upper tapered roller 3 with the cross section of the annular shaped preform 5, and then moving the core roller 4 radially toward the main roller 1, and the upper tapered roller 3 and the lower tapered roller 2 respectively rotate around their respective axis directions and move radially away from the main roller 1, so that the ring wall of the annular shaped preform 5 becomes thinner and the outer diameter increases, thereby obtaining the shaped martensitic stainless steel forging;

[0075] The feeding speed of the core roller is 0.4 mm / s, the linear speed of the main roller is 1200 mm / s, and the pressing speeds of the upper and lower tapered rollers are the same, which is 1 mm / s.

[0076] Example 3

[0077] This embodiment provides a special-shaped martensitic stainless steel forging, such as Figure 1 As shown, the forming and manufacturing method of the special-shaped martensitic stainless steel forging comprises the following steps:

[0078] (1) The electroslag ingot is subjected to three upsetting treatments, two drawing treatments, a punching treatment, and a hole expansion treatment in sequence to obtain a ring-shaped cross-section blank;

[0079] The deformation amount of each roughening and stretching treatment is 50%;

[0080] (2) The annular cross-section blank of step (1) is subjected to heat preservation treatment and then placed in a Figure 4 In the outer mold shown, Figure 5 The inner mold shown is placed in the inner hole of the annular cross-section blank, and then the inner mold is pressed into the annular cross-section blank by a press to obtain a Figure 2 The annular shaped preform shown in the figure; the temperature of the heat preservation treatment is 1200°C, and the heat preservation time is 0.3min / mm×effective thickness;

[0081] (3) placing the annular special-shaped preform obtained in step (2) on a ring rolling machine for ring rolling to obtain the special-shaped martensitic stainless steel forging;

[0082] Step (3) The ring rolling mill comprises a core roll 4, a main roll 1, an upper tapered roll 3 and a lower tapered roll 2; the outer surface of the main roll 1 is provided with a groove matching the outer surface shape of the annular special-shaped preform 5;

[0083] The core roller 4 has a convex structure matching the inner surface shape of the annular special-shaped preform 5;

[0084] like Figure 3 As shown, the ring rolling process includes: inserting the annular shaped preform 5 of step (2) into the core roller 4 and matching them with each other, matching the annular shaped preform 5 with the groove on the outer surface of the main roller 1, fitting the upper tapered roller 3 with the cross section of the annular shaped preform 5, and then moving the core roller 4 radially toward the main roller 1, and the upper tapered roller 3 and the lower tapered roller 2 respectively rotate around their respective axis directions and move radially away from the main roller 1, so that the ring wall of the annular shaped preform 5 becomes thinner and the outer diameter increases, thereby obtaining the shaped martensitic stainless steel forging;

[0085] The feeding speed of the core roller is 0.8 mm / s, the linear speed of the main roller is 1500 mm / s, and the pressing speeds of the upper and lower tapered rollers are the same, which is 1.5 mm / s.

[0086] Comprehensive analysis of Examples 1-3 shows that the method provided by the present invention can effectively improve the utilization rate of materials, shorten the processing cycle, and thus achieve mass production; and the obtained forgings can meet the product structure combination and performance requirements.

[0087] Example 4

[0088] This embodiment provides a special-shaped martensitic stainless steel forging. The forming and manufacturing method of the special-shaped martensitic stainless steel forging is different from that of Embodiment 1 only in that:

[0089] In this embodiment, the feed speed of the core roller in step (3) is adjusted to 0.2 mm / s.

[0090] Example 5

[0091] This embodiment provides a special-shaped martensitic stainless steel forging. The forming and manufacturing method of the special-shaped martensitic stainless steel forging is different from that of Embodiment 1 only in that:

[0092] In this embodiment, the feed speed of the core roller in step (3) is adjusted to 1.2 mm / s.

[0093] Compared with Example 1, Examples 4-5 adjust the feed speed of the core roller during the ring rolling process. If the feed speed of the core roller is too high, it will cause scabbing on the upper and lower end surfaces of the forging, thereby reducing the product yield. If the speed is too low, it will reduce production efficiency, thereby increasing production costs.

[0094] Example 6

[0095] This embodiment provides a special-shaped martensitic stainless steel forging. The forming and manufacturing method of the special-shaped martensitic stainless steel forging is different from that of Embodiment 1 only in that:

[0096] In this embodiment, the linear speed of the main roller in step (3) is adjusted to 1000 mm / s.

[0097] Example 7

[0098] This embodiment provides a special-shaped martensitic stainless steel forging. The forming and manufacturing method of the special-shaped martensitic stainless steel forging is different from that of Embodiment 1 only in that:

[0099] In this embodiment, the linear speed of the main roller in step (3) is adjusted to 1800 mm / s.

[0100] Compared with Example 1, Examples 6-7 adjust the linear speed of the main roller during the ring rolling process. If the linear speed of the main roller is too high, it will cause the product to flip. If the linear speed of the main roller is too low, the production efficiency will be reduced, thereby increasing the production cost.

[0101] Example 8

[0102] This embodiment provides a special-shaped martensitic stainless steel forging. The forming and manufacturing method of the special-shaped martensitic stainless steel forging is different from that of Embodiment 1 only in that:

[0103] In this embodiment, the pressing speed of the upper tapered roller in step (3) is adjusted to 1 mm / s, and the pressing speed of the lower tapered roller is adjusted to 1.5 mm / s, that is, the pressing speeds of the upper tapered roller and the lower tapered roller are different.

[0104] Example 9

[0105] This embodiment provides a special-shaped martensitic stainless steel forging. The forming and manufacturing method of the special-shaped martensitic stainless steel forging is different from that of Embodiment 1 only in that:

[0106] In this embodiment, the pressing speed of the upper tapered roller in step (3) is adjusted to 1.5 mm / s, and the pressing speed of the lower tapered roller is adjusted to 1 mm / s, that is, the pressing speeds of the upper tapered roller and the lower tapered roller are different.

[0107] Compared with Example 1, the pressing speeds of the upper and lower conical rollers described in Examples 8-9 are different; when the pressing speed of the upper conical roller is higher than that of the lower conical roller, or when the pressing speed of the lower conical roller is higher than that of the upper conical roller, roller climbing will occur during the production process.

[0108] A comprehensive analysis of Example 1 and Examples 4-9 shows that the selection of process parameters during the ring rolling process in step (3) will affect the structural uniformity and physical properties of the resulting forgings. Optimizing the ring rolling process parameters is beneficial to improving the yield of the resulting forgings and further improving material utilization.

[0109] Comparative Example 1

[0110] This comparative example provides a special-shaped martensitic stainless steel forging, and the forming and manufacturing method of the special-shaped martensitic stainless steel forging is different from that of Example 1 only in that:

[0111] In this comparative example, the process of placing the obtained annular cross-section blank in the fetal membrane for extrusion and deformation as described in step (2) is omitted, that is, the annular cross-section blank obtained in step (1) is directly subjected to the ring rolling process.

[0112] Compared with Example 1, when the ring rolling process is performed by the method provided in this comparative example, the ring rolling mill cannot achieve close contact with the shaped preform, which leads to greater resistance during the ring rolling process, thereby increasing the processing cycle and failing to achieve mass production; in addition, omitting the extrusion deformation process may result in the organizational structure or physical properties of the final product failing to meet product requirements. This further proves the indispensability of the steps of the method described in the present invention.

[0113] In summary, the method provided by the present invention can effectively improve the utilization rate of materials, shorten the processing cycle, and thus realize mass production; and the obtained forgings can meet the product structure combination and performance requirements.

[0114] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A forming and manufacturing method for a special-shaped martensitic stainless steel forging, characterized in that: The molding manufacturing method comprises the following steps: (1) The electroslag ingot is subjected to upsetting treatment, punching treatment and hole expansion treatment in sequence to obtain a ring-shaped cross-section blank; (2) placing the annular cross-section blank obtained in step (1) in a fetal membrane and extruding and deforming it to obtain an annular special-shaped preform; (3) placing the annular special-shaped preform obtained in step (2) on a ring rolling machine for ring rolling to obtain the special-shaped martensitic stainless steel forging; Step (3) The ring rolling mill comprises a core roll, a main roll, an upper tapered roll and a lower tapered roll; the outer surface of the main roll is provided with a groove matching the outer surface shape of the annular special-shaped preform; The core roller has a convex structure matching the inner surface shape of the annular special-shaped preform.

2. The molding manufacturing method according to claim 1, characterized in that: The upsetting treatment in step (1) includes three upsetting treatments and two lengthening treatments; Preferably, the deformation amount of each upsetting treatment in step (1) is 40-50%.

3. The molding manufacturing method according to claim 1 or 2, characterized in that: The fetal membrane in step (2) includes an outer mold and an inner mold.

4. The molding manufacturing method according to claim 3, characterized in that: The specific preparation method of the annular special-shaped preform described in step (2) includes: subjecting the annular cross-section blank described in step (1) to heat preservation treatment, and then placing it in an outer mold, and placing an inner mold in the inner hole of the annular cross-section blank, and then using a press to press the inner mold into the annular cross-section blank.

5. The molding manufacturing method according to claim 4, characterized in that: The temperature of the heat preservation treatment is 1150-1200°C; Preferably, the heat preservation time of the heat preservation treatment is 0.3 to 0.5 min / mm×effective thickness.

6. The molding manufacturing method according to claim 4, characterized in that: The difference between the outer diameter of the annular cross-section blank and the inner diameter of the outer die is 12 to 18 mm; Preferably, the height of the annular cross-section blank is 60 to 80 mm higher than the height of the annular special-shaped preform.

7. The molding manufacturing method according to any one of claims 1 to 6, characterized in that: The ring rolling process in step (3) includes: inserting the annular shaped preform in step (2) into the core roller and matching them with each other, matching the annular shaped preform with the groove on the outer surface of the main roller, fitting the upper tapered roller with the cross section of the annular shaped preform, and then moving the core roller radially toward the main roller, the upper tapered roller and the lower tapered roller rotate respectively around their respective axis directions and move radially away from the main roller, so that the annular wall of the annular shaped preform becomes thinner and the outer diameter increases, thereby obtaining the shaped martensitic stainless steel forging.

8. The molding manufacturing method according to claim 7, characterized in that: The feeding speed of the core roller is 0.4-0.8 mm / s; Preferably, the linear speed of the main roller is 1200-1500 mm / s.

9. The molding manufacturing method according to claim 7, characterized in that: The pressing speeds of the upper tapered roller and the lower tapered roller are the same; Preferably, the pressing speed of the upper tapered roller and the lower tapered roller is 1 to 1.5 mm / s.

10. A special-shaped martensitic stainless steel forging, characterized in that: The special-shaped martensitic stainless steel forging is obtained by the forming and manufacturing method according to any one of claims 1 to 9.

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