Manufacturing method of 42CrMo cylindrical shell part

Abstract

The invention discloses a manufacturing method of a 42CrMo cylindrical shell part, which comprises the following steps: 1) sawing and blanking raw materials to obtain a blank; 2) heating the blank and preserving heat; (3) upsetting is conducted on the heated blank, and die forging is conducted through a punch to obtain a cylindrical shell die forging blank; and (4) quenching and tempering heat treatment is conducted on the cylindrical shell die forging blank, a punch in the step (3) is of a big-end-up structure, and a fillet is arranged on the lower portion of the punch. The cylindrical shell forge piece is manufactured through die forging blank manufacturing, inner holes of cylindrical shell products can be shaped, consumption of overall raw materials is reduced, the forging working efficiency is improved, the cylindrical shell forge piece manufactured through the die forging forming process is small in section and light in weight, energy consumption is low in the subsequent heat treatment process, and the energy consumption is low. And the product forging efficiency can be improved by reducing the consumption of cutters and working hours during machining, the subsequent equipment machining time is shortened, the product delivery period is shortened, and the overall product cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of manufacturing alloy steel ring forgings, and particularly to a manufacturing method for 42CrMo cylindrical shell parts. Background Art

[0002] In the existing manufacturing methods for cylindrical shell forgings, generally the free forging rectangle method is adopted to make the product into a solid blind plate type. This forging method is simple, but has the defects of large raw material consumption, long subsequent heat treatment and processing time, low efficiency, and high cost. Specifically: 1) Due to the large difference in the inner and outer hole sizes of cylindrical shell products, the blanking allowance for ordinary free forging is large. After forging, rough turning before quenching and tempering must be carried out to ensure the qualified product performance in heat treatment. At the same time, rough turning before quenching and tempering will lead to too long product processing cycle and low production efficiency; 2) For rectangular cylindrical shell products, the energy consumption required during subsequent heat treatment, as well as the working hours and tool consumption during the processing process, will also increase synchronously, resulting in a significant increase in production cost.

[0003] In addition, in the existing manufacturing methods, there is also a method of punching a punch into a solid blind plate. This method also has problems of long time, low efficiency, and poor safety due to the small punch. Specifically: 1) The defects of the previous cylindrical shell products selected with small punches mainly focus on the defect of layer-by-layer heavy skin on the product after forging. Such defects greatly increase the difficulty of subsequent heat treatment requirements and easily lead to the risk of cracking during the heat treatment stage; 2) And machining causes great damage to the machining tools during the processing of heavy skin, and even the tool tip breaks during the processing, causing harm to the operator.

[0004] Therefore, at present, it is necessary to develop a manufacturing method for 42CrMo cylindrical shell parts to optimize the existing manufacturing process of cylindrical shell forgings to avoid the above-mentioned defects and problems. Summary of the Invention

[0005] The present invention is to overcome the above-mentioned defects existing in the prior art and provides a manufacturing method for 42CrMo cylindrical shell parts. The present invention uses die forging to make blanks for cylindrical shell forgings, which can form the inner hole of the cylindrical shell product, reduce the overall raw material consumption, and improve the working efficiency of forging. The cross-section of the cylindrical shell forging made by the die forging forming process is small and the weight is light, with lower energy consumption during subsequent heat treatment, and the consumption of tools and working hours during processing is reduced, which can improve the forging efficiency of the product, reduce the subsequent processing equipment time, shorten the product delivery cycle, and save the overall product cost.

[0006] The technical solution adopted by the present invention to solve its technical problems is:

[0007] A manufacturing method for a 42CrMo cylindrical shell part, comprising the following steps:

[0008] 1) Saw the raw material into blanks;

[0009] 2) Heat and hold the blank;

[0010] 3) Upset the heated blank and perform die forging with a punch to obtain a die-forged blank of the cylindrical shell;

[0011] 4) Perform quenching and tempering heat treatment on the die-forged blank of the cylindrical shell.

[0012] The heating temperature in step 2) is 1230 ± 20 °C, and the holding time is determined based on the thickness of the blank, which is 2.0 mm / min to 3.0 mm / min.

[0013] The punch in step 3) has an upper-large and lower-small structure, and a fillet is provided at the lower part.

[0014] The preparation steps of the die-forged blank of the cylindrical shell in step 3) are as follows:

[0015] S1: Preheat the punch to about 300 °C;

[0016] S2: Take the heated billet out of the furnace and perform upsetting and drawing to change the billet into a blank so that the size of the blank meets the requirements for entering the die;

[0017] S3: After rounding and flattening the upset blank, punch the punch into the blank in sequence to obtain a die-forged blank of the cylindrical shell.

[0018] The quenching and tempering heat treatment in step 4) includes the following steps:

[0019] S1: Put the die-forged blank of the cylindrical shell into a quenching and tempering heat treatment furnace;

[0020] S2: Heat the die-forged blank of the cylindrical shell to 850 °C to 900 °C at a rate of ≤ 150 °C / h, determine the holding time based on the wall thickness of the cylindrical shell and perform holding, and the holding time is 30 mm / h to 50 mm / h;

[0021] S3: Take the die-forged blank of the cylindrical shell out of the furnace after holding, perform water cooling, and perform air cooling to room temperature when the surface temperature drops to about 300 °C;

[0022] S4: Put the die-forged blank of the cylindrical shell into a tempering furnace, heat the die-forged blank of the cylindrical shell to 600 °C to 620 °C at a heating rate of ≤ 150 °C / h, and determine the holding time based on the wall thickness of the die-forged blank of the cylindrical shell and perform holding, and the holding time is 30 mm / h to 50 mm / h.

[0023] The manufacturing method of the 42CrMo cylindrical shell parts further includes the following steps:

[0024] 1) Rough machine the die forging blank of the cylindrical shell after quenching and tempering heat treatment to obtain the cylindrical shell;

[0025] 2) Perform ultrasonic testing on the rough machined cylindrical shell;

[0026] 3) Finish machine the cylindrical shell that has passed the ultrasonic testing;

[0027] 4) Inspect and test the finish machined cylindrical shell to meet the specified technical requirements.

[0028] The surface roughness of the rough machined cylindrical shell is ≤ Ra12.5μm.

[0029] The beneficial effects of the present invention are as follows:

[0030] 1. The present invention uses die forging to produce the cylindrical shell forgings, which can form the inner hole of the cylindrical shell products, and greatly reduce the consumption of the overall raw materials.

[0031] 2. While reducing the consumption of raw materials, the present invention reduces the requirements for the forging equipment capabilities needed, such as for the equipment price, brand, model, performance, etc. As long as it can meet the production needs, it is fine. It can also make full use of the forging equipment in the existing technology, thereby reducing the equipment cost, reducing the equipment energy consumption, and further improving the working efficiency of forging.

[0032] 3. The cylindrical shell forgings produced by the die forging forming process of the present invention have a smaller cross-section and lighter weight. During subsequent heat treatment, the energy consumption is lower, and the consumption of tools and working hours during processing is also reduced synchronously, reducing the use and maintenance costs.

[0033] 4. The present invention can improve the forging efficiency of products, reduce the time of subsequent processing equipment, shorten the product delivery cycle, save the overall product cost, and improve the economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The following further describes the present invention in conjunction with the drawings and embodiments:

[0035] Figure 1 is the schematic diagram of the working process of the embodiment in the present invention;

[0036] Figure 2 is the schematic diagram of the structure of the punch in the present invention;

[0037] Figure 3 is the schematic diagram of the structure of die forging the blank with the punch in the present invention.

[0038] In the figure, 1. punch, 11. rounded corner, 2. forged blank of cylindrical shell die forging. Detailed implementation mode

[0039] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0040] As Figures 1-3 shown, a manufacturing method for a 42CrMo cylindrical shell part includes the following steps: 1) Saw and cut the raw material to obtain a blank;

[0041] 2) Heat and keep the blank warm;

[0042] 3) Upset the heated blank and perform die forging with a punch to obtain a forged blank of cylindrical shell die forging;

[0043] 4) Perform quenching and tempering heat treatment on the forged blank of cylindrical shell die forging.

[0044] The heating temperature in step 2) is 1230 °C, and the holding time is determined based on the thickness of the blank, which is 3.mm / min.

[0045] The punch 1 in step 3) has an upper-large and lower-small structure, and a rounded corner 11 is provided at the lower part.

[0046] The preparation steps of the forged blank 2 of cylindrical shell die forging in step 3) are as follows:

[0047] S1: Preheat the punch to about 300 °C;

[0048] S2: Take the heated blank out of the furnace and perform upsetting and drawing to change it into a blank so that the size of the blank meets the requirements for entering the mold;

[0049] S3: After rolling and flattening the upset blank, punch the punch into the blank in sequence to obtain a forged blank of cylindrical shell die forging.

[0050] The quenching and tempering heat treatment in step 4) includes the following steps:

[0051] S1: Put the forged blank of cylindrical shell die forging into a quenching and tempering heat treatment furnace;

[0052] S2: Heat the forged blank of cylindrical shell die forging to 850 °C at a speed of ≤150 °C / h, determine the holding time based on the wall thickness of the cylindrical shell and perform holding, and the holding time is 50mm / h;

[0053] S3: Take out the warm cylindrical shell die forging billet from the furnace, carry out water cooling, and when the surface temperature drops to 300 °C, carry out air cooling to room temperature;

[0054] S4: Put the cylindrical shell die forging billet into a tempering furnace, heat the cylindrical shell die forging billet to 610 °C at a heating rate of ≤145 °C / h, and determine the holding time based on the wall thickness of the cylindrical shell die forging billet and carry out holding, and the holding time is 40 mm / h.

[0055] The manufacturing method of the 42CrMo cylindrical shell parts further includes the following steps:

[0056] 1) Rough machine the cylindrical shell die forging billet after quenching and tempering heat treatment to obtain a cylindrical shell;

[0057] 2) Carry out ultrasonic testing on the rough machined cylindrical shell;

[0058] 3) Finish machine the cylindrical shell that passes the ultrasonic testing;

[0059] 4) Inspect and test the finish machined cylindrical shell to meet the specified technical requirements.

[0060] The surface roughness of the rough machined cylindrical shell is ≤Ra12.5 μm.

[0061] The manufacturing method of the 42CrMo cylindrical shell parts of the present invention improves process flow planning, blanking, die forging blanking, quenching and tempering treatment, machining, final inspection and other steps. By using die forging blanking, the inner holes of different sizes of the cylindrical shell forgings can be forged into shape. By using die forging blanking to make the cylindrical shell forgings, the inner holes of the cylindrical shell products can be formed, which greatly reduces the consumption of the overall raw materials; it reduces the raw material consumption and production cost and improves the production efficiency. While reducing the raw material consumption, the forging hammer and loading and unloading machine required for blanking are also reduced synchronously, thus greatly reducing the production cost; the cross-section of the cylindrical shell forgings made by the die ring rolling forming process of the present invention is smaller and the weight is lighter, and the energy consumption during subsequent heat treatment is lower, and the consumption of cutting tools and working hours during machining is also reduced synchronously;

[0062] Example 2

[0063] Combined with Example 1, a manufacturing method of 42CrMo cylindrical shell parts includes the following steps: 1) Saw and blank the raw materials to obtain blanks;

[0064] 2) Heat and hold the blanks;

[0065] 3) Upset the heated blanks and carry out die forging with a punch to obtain a cylindrical shell die forging billet;

[0066] 4) Perform quenching and tempering heat treatment on the die-forged blank of the cylindrical shell.

[0067] The heating temperature in step 2) is 1210 °C, and the holding time is determined based on the thickness of the blank, which is 2.0 mm / min.

[0068] The punch 1 in step 3) has an upper-large and lower-small structure, and a fillet 11 is provided at the lower part.

[0069] The preparation steps of the die-forged blank 2 of the cylindrical shell in step 3) are as follows:

[0070] S1: Preheat the punch to about 295 °C;

[0071] S2: Take the heated billet out of the furnace and perform upsetting and drawing to change the material into a blank, so that the size of the blank meets the requirements for entering the mold;

[0072] S3: After rounding and flattening the upset blank, punch the punch into the blank in sequence to obtain the die-forged blank of the cylindrical shell.

[0073] The quenching and tempering heat treatment in step 4) includes the following steps:

[0074] S1: Put the die-forged blank of the cylindrical shell into the quenching and tempering heat treatment furnace;

[0075] S2: Heat the die-forged blank of the cylindrical shell to 900 °C at a speed of 147 °C / h, determine the holding time based on the wall thickness of the cylindrical shell and perform holding, and the holding time is 30 mm / h;

[0076] S3: Take the die-forged blank of the cylindrical shell out of the furnace after holding, perform water cooling, and when the surface temperature drops to about 298 °C, perform air cooling to room temperature;

[0077] S4: Put the die-forged blank of the cylindrical shell into the tempering furnace, heat the die-forged blank of the cylindrical shell to 620 °C at a heating rate of ≤145 °C / h, and determine the holding time based on the wall thickness of the die-forged blank of the cylindrical shell and perform holding, and the holding time is 30 mm / h.

[0078] The manufacturing method of the 42CrMo cylindrical shell parts further includes the following steps:

[0079] 1) Perform rough machining on the die-forged blank of the cylindrical shell after quenching and tempering heat treatment to obtain a cylindrical shell;

[0080] 2) Perform ultrasonic testing on the cylindrical shell after rough machining;

[0081] 3) Perform finish machining on the cylindrical shell qualified by ultrasonic testing;

[0082] 4) Inspect and test the machined cylindrical shell to meet the specified technical requirements.

[0083] The surface roughness of the cylindrical shell after rough machining is ≤ Ra12.5μm.

[0084] For other contents, refer to Embodiment 1 and will not be elaborated here.

[0085] Embodiment 3

[0086] A manufacturing method for 42CrMo cylindrical shell parts, comprising the following steps:

[0087] 1) Cut the raw material by sawing to obtain a blank.

[0088] 2) Heat and hold the blank.

[0089] 3) Upset the heated blank and perform die forging with a punch to obtain a die-forged blank of the cylindrical shell.

[0090] 4) Perform quenching and tempering heat treatment on the die-forged blank of the cylindrical shell.

[0091] The heating temperature in step 2) is 1250°C, and the holding time is determined based on the thickness of the blank, which is 2.5 mm / min.

[0092] The punch 1 in step 3) has an upper-large and lower-small structure, and a fillet 11 is provided at the lower part.

[0093] The preparation steps of the die-forged blank 2 of the cylindrical shell in step 3) are as follows:

[0094] S1: Preheat the punch to about 302°C.

[0095] S2: Take the heated billet out of the furnace and upset and draw it into a blank to make the size of the blank meet the requirements for entering the die.

[0096] S3: After rolling and flattening the upset blank, drive the punch into the blank in sequence to obtain a die-forged blank of the cylindrical shell.

[0097] The quenching and tempering heat treatment in step 4) includes the following steps:

[0098] S1: Put the die-forged blank of the cylindrical shell into a quenching and tempering heat treatment furnace.

[0099] S2: Heat the die-forged blank of the cylindrical shell to 870°C at a speed of ≤ 150°C / h, determine the holding time based on the wall thickness of the cylindrical shell and perform holding, and the holding time is 40 mm / h.

[0100] S3: Take out the warm cylindrical shell die forging billet from the furnace, conduct water cooling, and when the surface temperature drops to about 300 °C, conduct air cooling to room temperature;

[0101] S4: Place the cylindrical shell die forging billet into a tempering furnace, heat the cylindrical shell die forging billet to 600 °C at a heating rate of ≤150 °C / h, and determine the holding time based on the wall thickness of the cylindrical shell die forging billet and conduct holding, and the holding time is 50 mm / h.

[0102] The manufacturing method of the 42CrMo cylindrical shell parts further includes the following steps:

[0103] 1) Rough machine the cylindrical shell die forging billet after quenching and tempering heat treatment to obtain a cylindrical shell;

[0104] 2) Conduct ultrasonic testing on the rough machined cylindrical shell;

[0105] 3) Finish machine the cylindrical shell that passes the ultrasonic testing;

[0106] 4) Inspect and test the finish machined cylindrical shell to meet the specified technical requirements.

[0107] The surface roughness of the rough machined cylindrical shell is ≤Ra12.5 μm.

[0108] For other contents, refer to Embodiment 1 and will not be elaborated here.

[0109] In the description of the present invention, the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "vertical", "horizontal", etc. is the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for describing the present invention and does not require the present invention to be constructed or operated in a specific orientation. Therefore, it cannot be understood as a limitation to the present invention. The "connected" and "connected" in the present invention should be understood in a broad sense. For example, it can be a connection or a detachable connection; it can be a direct connection or an indirect connection through an intermediate component. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific situations.

[0110] The above is the preferred embodiment of the present invention. The description of specific embodiments is only for better understanding the idea of the present invention. For those of ordinary skill in the art, several improvements or equivalent replacements can be made according to the principle of the present invention, and these improvements or equivalent replacements are also regarded as falling within the protection scope of the present invention.

Claims

1. A method for manufacturing 42CrMo cylindrical shell parts, characterized in that: The following steps are involved: 1) The raw materials are sawn and cut to obtain blanks; 2) Heating and keeping the blank warm; 3) upsetting the heated blank and die forging with a punch to obtain a cylindrical shell die forging blank; 4) Perform tempering heat treatment on the cylindrical shell die forging blank.

2. A method for manufacturing 42CrMo cylindrical shell parts as claimed in claim 1, characterized in that: The heating temperature in the step 2) is 1230±20° C., and the holding time is determined based on the thickness of the blank, which is 2.0 mm / min to 3.0 mm / min.

3. A method for manufacturing 42CrMo cylindrical shell parts as claimed in claim 1, characterized in that: The punch in step 3) adopts a structure that is larger at the top and smaller at the bottom, wherein the bottom is provided with rounded corners.

4. A method for manufacturing 42CrMo cylindrical shell parts as claimed in claim 1, characterized in that: The steps of preparing the cylindrical shell die forging blank in step 3) are as follows: S1: preheating the punch to 300° C. S2: taking the heated blank out of the furnace and performing upsetting and drawing to transform the blank into a blank, so that the size of the blank meets the requirements for entering the mold; S3: After the roughened blank is rounded and flattened, punches are driven into the blank in sequence to obtain a cylindrical shell die forging blank.

5. A method for manufacturing 42CrMo cylindrical shell parts as claimed in claim 1, characterized in that: The quenching and tempering heat treatment in step 4) comprises the following steps: S1: placing the cylindrical shell die forging billet into a quenching and tempering heat treatment furnace; S2: heating the cylindrical shell die forging billet to 850°C to 900°C at a speed of ≤150°C / h, determining a holding time based on the wall thickness of the cylindrical shell and performing the holding, wherein the holding time is 30mm / h to 50mm / h; S3: taking the heat-insulated cylindrical shell die forging billet out of the furnace, water-cooling it, and air-cooling it to room temperature when the surface temperature drops to 300°C; S4: Place the cylindrical shell die forging billet into a tempering furnace, heat the cylindrical shell die forging billet to 600°C~620°C at a heating rate of ≤150°C / h, and determine the insulation time based on the wall thickness of the cylindrical shell die forging billet and perform insulation, the insulation time is 30mm / h~50mm / h.

6. A method for manufacturing 42CrMo cylindrical shell parts as claimed in claim 1, characterized in that: The following steps are also included: 1) rough machining the cylindrical shell die forging blank after quenching and tempering heat treatment to obtain a cylindrical shell; 2) Perform ultrasonic testing on the cylindrical shell after rough machining; 3) Finishing the cylindrical shell that has passed the ultrasonic test; 4) Inspect and test the cylindrical shell after fine processing to ensure it meets the specified technical requirements.

7. A method for manufacturing 42CrMo cylindrical shell parts as claimed in claim 6, characterized in that: The surface roughness of the cylindrical shell after rough machining is ≤Ra12.5μm.

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