CN115647266A - Forging method for producing large-specification bearing steel forged blank by square blank - Google Patents
Forging method for producing large-specification bearing steel forged blank by square blank Download PDFInfo
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- CN115647266A CN115647266A CN202211326078.3A CN202211326078A CN115647266A CN 115647266 A CN115647266 A CN 115647266A CN 202211326078 A CN202211326078 A CN 202211326078A CN 115647266 A CN115647266 A CN 115647266A
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Abstract
The invention relates to a forging method for producing a large-specification bearing steel forging billet by using a square billet, belonging to the technical field of square billet forging. The forging method comprises the following steps: (1) heating: the continuous casting square billet adopts a hot delivery mode, and the square billet is heated to 1250-1270 ℃ and then is subjected to heat preservation for 13-17 h; (2) drawing out: and (3) drawing the square billet after heating and heat preservation, wherein the forging ratio is 2.2-2.4, and the reduction per pass is 0.25-0.27 times of the height of the section of the forging billet of the previous pass. The invention adopts a one-time square billet compaction process to improve the internal quality of a high-carbon chromium bearing steel product, so that the forged steel product has compact structure, the flaw detection quality requirement is further met, and reworking and quality waste products are reduced.
Description
Technical Field
The invention belongs to the technical field of square billet forging, and particularly relates to a forging method for producing a large-specification bearing steel forging billet by using a square billet.
Background
The forging is to utilize the plasticity of the material to generate plastic deformation under the action of external force so as to obtain the forging with required shape, size and certain tissue performance. The bearing steel is used for manufacturing balls, rollers, sleeves and the like of rolling bearings, and can also be used for manufacturing precision measuring tools, such as dies, measuring tools, screw taps and precision parts of diesel oil pumps. In order to improve the yield and shorten the delivery production period, more and more bearing steel forging materials are produced by adopting a continuous casting round billet mode at present, but the defects of final finished product flaw detection exceed the standard due to direct drawing without upsetting, insufficient internal deformation of continuous casting billets and poor center loosening and welding.
At present, high-carbon chromium bearing steel forged billets with the diameter of 380-400mm are produced by steel ingots, and the steel ingots have dead heads, so that the quality is poor, and the steel ingots need to be cut off after finished products, so that the yield is low, and is generally about 80%. The high-carbon chromium bearing steel forging stock with the diameter of 380-400mm meets the requirements of the part 8 forging of JB-T5000.8-2007 general technical conditions for heavy machinery: when a steel ingot is used for forging, the forging ratio of a steel ingot without upsetting is generally not less than 3, and the forging ratio of a common forged product in the forging industry is actually more than 4, so that the flaw detection level of the product can meet the use requirement.
The method adopts a steel ingot to produce the high-carbon chromium bearing steel forging stock with the diameter of 380-400mm, the forging heat number is generally 3-4, and the method not only causes the increase of the production cost, influences the production efficiency of the product, but also causes the waste of raw materials.
Therefore, the high-carbon bearing steel has the defects that the continuous casting square billet is easy to form loose due to high C content, the center loose is more serious compared with the center loose of common alloy steel, effective measures need to be taken by forging, and the problem of loose shrinkage cavity is solved under the condition of low forging ratio and low cost.
Disclosure of Invention
The invention provides a forging method for producing a large-specification bearing steel forging stock by using a square billet. The forging method provided by the invention determines a suitable cogging process by combining the characteristics of steel grades under the condition of not increasing an upsetting process, improves the internal quality of a high-carbon chromium bearing steel product by adopting a one-time square billet compaction process, reduces the center porosity of a blank to further improve the internal quality of a forging billet, enables the forged steel product to have compact structure, further meets the requirement on flaw detection quality, reduces reworking and quality waste products, and remarkably improves the production efficiency.
In order to solve the technical problems, the invention adopts the following technical scheme: a forging method for producing a large-specification high-carbon chromium bearing steel forging stock by using a square billet comprises the following steps:
(1) Heating: the continuous casting square billet adopts a hot delivery mode, the square billet is heated to 1250-1270 ℃ and then is subjected to heat preservation, and the heat preservation time is 13-17 h;
(2) Drawing out: and drawing the square billet after heating and heat preservation, wherein the forging ratio is 2.2-2.4, and the reduction of each pass is 0.25-0.27 times of the height of the section of the forging billet of the previous pass.
In the heating in the step (1) of the invention, the specification of the continuous casting square billet is 430-460mm by 610-650 mm.
In the heating in the step (1), after the square billet is fed in a hot manner, the temperature of the fed square billet is more than or equal to 550 ℃, and the heating speed is less than or equal to 50 ℃/h.
In the step (2) of drawing, the forging drawing passes are 4 times, and the die is turned for 90 degrees after each drawing pass.
The high-carbon chromium bearing steel forging stock comprises the following chemical components in percentage by mass: c:0.95% -1.05%, si: 0.15-0.35%, mn: 0.25-0.45%, cr:1.40 to 1.65 percent of Mo, less than or equal to 0.1 percent of P, less than or equal to 0.020 percent of S, less than or equal to 0.0012 percent of O.
The diameter phi of the high-carbon chromium bearing steel forging blank is 380-400 mm.
The flaw detection level of the high-carbon chromium bearing steel forging blank reaches SEP 1921E/E grade, and the specific standards are as follows: the diameter of a single point discontinuous equivalent flat-bottom hole is less than or equal to 3mm, and the diameter of a long or dense point discontinuous equivalent flat-bottom hole is less than or equal to 2mm.
The high-carbon chromium bearing steel forging billet is generally less than or equal to 0.5 grade in porosity, less than or equal to 0.5 grade in central porosity, less than or equal to 3.0 in banded structure and free of microscopic pores.
The high-carbon chromium bearing steel forging blank carbide liquation is 0.5.
The invention adopts an improved high-temperature diffusion process of the steel ingot before forging, improves the heating temperature of the steel ingot, designs an optimal heating process, adjusts the heat preservation time, designs a reasonable pressing process, adopts a 4-pass compaction process, ensures that the specification of a forging stock produced by a bearing steel square billet reaches 380mm-400mm, the flaw detection level reaches SEP 1921E/E level, and produces qualified products with the minimum cost.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: 1. the high-carbon chromium bearing steel forged blank produced by the invention can be used for producing qualified high-carbon chromium bearing steel forged blank products under the condition of small forging ratio by reasonably designing heating and heat preservation and forging high reduction process, and the problems of casting blank center looseness and uneven carbide are effectively solved. 2. The forging method provided by the invention determines a proper cogging process under the condition of not increasing an upsetting process, improves the internal quality of a high-carbon chromium bearing steel product by adopting a one-time drawing process, reduces the central porosity of a blank to further improve the internal quality of a forged blank, enables the forged steel product to have a compact structure, further meets the requirement of flaw detection quality, enables the flaw detection of a product with the specification of phi 380-400mm to reach an optimal level, reduces reworking and quality waste products, and remarkably improves the production efficiency.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
Example 1
A forging method for producing a large-size high-carbon chromium bearing steel forging stock by using a square stock adopts the following specific processes:
(1) Heating: producing a forging stock product made of GCr15, wherein the section specification of a square stock is 460mm x 610mm, the continuous casting square stock adopts a hot delivery mode, the hot delivery temperature is 580 ℃, the temperature rise speed is 40 ℃/h, the square stock is heated to 1250 ℃ and then is subjected to heat preservation, and the heat preservation time is 14h;
(2) Drawing out: and (3) drawing the heated and insulated square billet, drawing the square billet by using a 350mm flat anvil by adopting a direct drawing forging process with a forging ratio of 2.4, wherein the fillet radius of the wide flat anvil is 35mm, and the length of the wide flat anvil is 1300mm.
The forging drawing passes are 4 times, each pass is turned over for 90 degrees after drawing, then the next pass is drawn, the reduction of each pass is 0.25 time of the height of the section of the forging stock of the previous pass, and after 4 passes of drawing, the forging stock is rounded and finished into a forging stock product with the diameter of 380 mm.
The chemical composition and percentage content of the high-carbon chromium bearing steel forging stock obtained in the embodiment are shown in table 1, and the specification and performance are shown in table 2. The ultrasonic flaw detection meets the SEP 1921E/E grade requirement.
Example 2
A forging method for producing a large-size high-carbon chromium bearing steel forging stock by using a square stock adopts the following specific processes:
(1) Heating: producing a forging stock product made of GCr15, wherein the section specification of a square stock is 430mm x 650mm, the continuous casting square stock adopts a hot delivery mode, the hot delivery temperature is 560 ℃, the temperature rise speed is 50 ℃/h, the square stock is heated to 1260 ℃, and then the heat preservation is carried out, and the heat preservation time is 15h;
(2) Drawing out: and (3) drawing the square billet subjected to heating and heat preservation, adopting a direct drawing forging process with a forging ratio of 2.3, drawing by using a 350mm flat anvil, wherein the fillet radius of the wide flat anvil is 35mm, and the length of the wide flat anvil is 1300mm.
The forging drawing pass is 4 times, each pass is turned over 90 degrees after drawing, then the next pass is drawn, the reduction of each pass is 0.27 times of the height of the section of the forging stock of the previous pass, and after 4 passes of drawing, the forging stock is rounded and finished into a forging stock product with the diameter of 390 mm.
The chemical composition and percentage content of the high-carbon chromium bearing steel forging stock obtained in the embodiment are shown in table 1, and the specification and performance are shown in table 2. The ultrasonic flaw detection meets the SEP 1921E/E grade requirement.
Example 3
A forging method for producing a large-size high-carbon chromium bearing steel forging stock by using a square stock adopts the following specific processes:
(1) Heating: producing a forging stock product made of GCr15, wherein the section specification of a square stock is 440mm x 630mm, a continuous casting square stock adopts a hot delivery mode, the hot delivery temperature is 580 ℃, the temperature rise speed is 30 ℃/h, the square stock is heated to 1270 ℃ and then is subjected to heat preservation, and the heat preservation time is 17h;
(2) Drawing out: and (3) drawing the square billet subjected to heating and heat preservation, adopting a direct drawing forging process with the forging ratio of 2.2, drawing by using a 350mm flat anvil, wherein the fillet radius of the wide flat anvil is 35mm, and the length of the wide flat anvil is 1300mm.
The forging drawing pass is 4 times, each pass is turned over 90 degrees after drawing, then the next pass is drawn, the reduction of each pass is 0.26 time of the height of the section of the forging stock of the previous pass, and after 4 passes of drawing, the forging stock is rounded and finished into a forging stock product with the diameter of 400mm.
The chemical components and the percentage content of the high-carbon chromium bearing steel forging stock obtained in the embodiment are shown in a table 1, and the specification and the performance are shown in a table 2. The ultrasonic flaw detection meets the SEP 1921E/E grade requirement.
Example 4
A forging method for producing a large-size high-carbon chromium bearing steel forging stock by using a square stock adopts the following specific processes:
(1) Heating: producing a forging stock product with the material quality of GCr15, wherein the section specification of a square stock is 460mm x 610mm, a hot delivery mode is adopted for a continuous casting square stock, the hot delivery temperature is 550 ℃, the temperature rise speed is 50 ℃/h, the heat preservation is carried out after the square stock is heated to 1255 ℃, and the heat preservation time is 13h;
(2) Drawing out: and (3) drawing the square billet subjected to heating and heat preservation, adopting a direct drawing forging process with the forging ratio of 2.2, drawing by using a 350mm flat anvil, wherein the fillet radius of the wide flat anvil is 35mm, and the length of the wide flat anvil is 1300mm.
The forging drawing pass is 4 times, each pass is turned over 90 degrees after drawing, then the next pass is drawn, the reduction of each pass is 0.27 times of the height of the section of the forging stock of the previous pass, and after 4 passes of drawing, the forging stock with the diameter of 385mm is finished in a circle mode.
The chemical composition and percentage content of the high-carbon chromium bearing steel forging stock obtained in the embodiment are shown in table 1, and the specification and performance are shown in table 2. The ultrasonic flaw detection meets the SEP 1921E/E grade requirement.
Example 5
A forging method for producing a large-size high-carbon chromium bearing steel forging stock by using a square stock adopts the following specific processes:
(1) Heating: producing a forging stock product with the material quality of GCr15, wherein the section specification of a square stock is 460mm x 610mm, the continuous casting square stock adopts a hot delivery mode, the hot delivery temperature is 585 ℃, the temperature rise speed is 45 ℃/h, the square stock is heated to 1268 ℃ and then is subjected to heat preservation, and the heat preservation time is 16h;
(2) Drawing out: and (3) drawing the heated and insulated square billet, drawing the square billet by using a 350mm flat anvil by adopting a direct drawing forging process with a forging ratio of 2.3, wherein the fillet radius of the wide flat anvil is 35mm, and the length of the wide flat anvil is 1300mm.
The forging drawing passes are 4 times, each pass is turned over for 90 degrees after drawing, then the next pass is drawn, the reduction of each pass is 0.26 time of the height of the section of the forging stock of the previous pass, and after 4 passes of drawing, the forging stock with the diameter of 395mm is obtained through circle finishing.
The chemical composition and percentage content of the high-carbon chromium bearing steel forging stock obtained in the embodiment are shown in table 1, and the specification and performance are shown in table 2. The ultrasonic flaw detection meets the SEP 1921E/E grade requirement.
Example 6
A forging method for producing a large-size high-carbon chromium bearing steel forging stock by using a square stock adopts the following specific processes:
(1) Heating: producing a forging stock product made of GCr15, wherein the section specification of a square stock is 460mm x 610mm, a continuous casting square stock adopts a hot delivery mode, the hot delivery temperature is 590 ℃, the temperature rise speed is 35 ℃/h, the square stock is heated to 1265 ℃ and then is subjected to heat preservation, and the heat preservation time is 15.5h;
(2) Drawing out: and (3) drawing the heated and insulated square billet, drawing the square billet by using a 350mm flat anvil by adopting a direct drawing forging process with a forging ratio of 2.2, wherein the fillet radius of the wide flat anvil is 35mm, and the length of the wide flat anvil is 1300mm.
The forging drawing pass is 4 times, each pass is turned over 90 degrees after drawing, then the next pass is drawn, the reduction of each pass is 0.25 time of the height of the section of the forging stock of the previous pass, and after 4 passes of drawing, the forging stock is rounded and finished into a forging stock product with the diameter of 380 mm.
The chemical composition and percentage content of the high-carbon chromium bearing steel forging stock obtained in the embodiment are shown in table 1, and the specification and performance are shown in table 2. The ultrasonic flaw detection meets the SEP 1921E/E grade requirement.
Table 1 examples 1-6 chemical composition of high carbon chromium bearing steel forging stock and percentage thereof (%)
TABLE 2 examples 1-6 high carbon chromium bearing steel forged stock specifications and properties
By comparison, the high-carbon chromium bearing steel forged blanks produced by the once-drawing forging method in the examples 1 to 6 have the flaw detection level of products with the specification phi of 380-400mm reaching the optimal level. According to the embodiment, the forging method provided by the invention determines a suitable cogging process under the condition of not increasing an upsetting process, improves the internal quality of a high-carbon chromium bearing steel product by adopting a one-time drawing process, reduces the center porosity of a blank to further improve the internal quality of a forging blank, enables the forged steel product to have a compact structure, further meets the flaw detection quality requirement, reduces reworking and quality waste products, and remarkably improves the production efficiency.
Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention any modifications and equivalents.
Claims (9)
1. A forging method for producing a large-specification high-carbon chromium bearing steel forging stock by using a square billet is characterized by comprising the following steps: the forging method comprises the following steps:
(1) Heating: the continuous casting square billet adopts a hot delivery mode, and the square billet is heated to 1250-1270 ℃ and then is subjected to heat preservation for 13-17 h;
(2) Drawing out: and (3) drawing the square billet after heating and heat preservation, wherein the forging ratio is 2.2-2.4, and the reduction per pass is 0.25-0.27 times of the height of the section of the forging billet of the previous pass.
2. The forging method for producing the large-specification high-carbon chromium bearing steel forging stock by the square stock as claimed in claim 1, wherein the forging method comprises the following steps: in the heating in the step (1), the specification of the square billet of the continuous casting square billet is 430-460mm by 610-650 mm.
3. The forging method for producing the large-specification high-carbon chromium bearing steel forging stock by the square stock according to claim 1, wherein the forging method comprises the following steps: in the heating in the step (1), after the square billet is hot-delivered, the hot-delivery temperature is more than or equal to 550 ℃, and the heating speed is less than or equal to 50 ℃/h.
4. The forging method for producing the large-specification high-carbon chromium bearing steel forging stock by the square stock according to claim 1, wherein the forging method comprises the following steps: in the step (2), in the drawing, the forging drawing passes are 4 times, and the die is turned over by 90 degrees after drawing in each pass.
5. The forging method for producing the large-specification high-carbon chromium bearing steel forging stock by the square stock as claimed in claim 1, wherein the forging method comprises the following steps: the high-carbon chromium bearing steel forging stock comprises the following chemical components in percentage by mass: c:0.95% -1.05%, si: 0.15-0.35%, mn: 0.25-0.45%, cr:1.40 to 1.65 percent of the total weight of the alloy, less than or equal to 0.1 percent of Mo, less than or equal to 0.020 percent of P, less than or equal to 0.020 percent of S, and less than or equal to 0.0012 percent of O.
6. The forging method for producing a large-size high-carbon chromium bearing steel forging stock by using the square stock as claimed in any one of claims 1 to 5, wherein the forging method comprises the following steps: the diameter phi of the high-carbon chromium bearing steel forging blank is 380-400 mm.
7. The forging method for producing a large-size high-carbon chromium bearing steel forging stock by using the square stock as claimed in any one of claims 1 to 5, wherein the forging method comprises the following steps: the flaw detection level of the high-carbon chromium bearing steel forging blank reaches SEP 1921E/E level.
8. The forging method for producing the forged blank of the large-specification high-carbon chromium bearing steel by the square billet according to any one of claims 1 to 5, wherein the forging method comprises the following steps: the high-carbon chromium bearing steel forging billet is generally less than or equal to 0.5 grade in porosity, less than or equal to 0.5 grade in central porosity, less than or equal to 3.0 grade in banded structure and free of microscopic pores.
9. The forging method for producing the forged blank of the large-specification high-carbon chromium bearing steel by the square billet according to any one of claims 1 to 5, wherein the forging method comprises the following steps: the liquation of the carbide of the high-carbon chromium bearing steel forging blank is less than or equal to 0.5 grade.
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| CN202211326078.3A CN115647266A (en) | 2022-10-27 | 2022-10-27 | Forging method for producing large-specification bearing steel forged blank by square blank |
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| CN202211326078.3A CN115647266A (en) | 2022-10-27 | 2022-10-27 | Forging method for producing large-specification bearing steel forged blank by square blank |
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