Cold rolling working roll and preparation method thereof
By controlling the heating temperature and holding time through multiple hot forging and post-forging heat treatment, the problem of uneven distribution of liquid carbides in cold rolling work rolls was solved, achieving uniform dispersion of liquid carbides and improving the fatigue resistance of work rolls.
Patent Information
- Application Number
- CN202511973927.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-02-10
AI Technical Summary
Existing cold rolling work rolls are prone to forming network or chain-like liquid carbides during the manufacturing process, which can lead to fatigue crack initiation and cause roll body spalling or breakage.
By employing multiple forging processes and post-forging heat treatment, and by controlling the heating temperature and holding time, the liquid carbides are dissolved and finely distributed in the austenitic matrix, avoiding network or chain-like distribution.
It effectively avoids the network or chain distribution of liquid carbides in cold rolling work rolls, improves the fatigue resistance of work rolls, and reduces the risk of roll spalling and roll breakage.
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Figure CN121491258A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of forging technology, in particular to a cold rolling work roll and a preparation method thereof. BACKGROUND
[0002] The cold rolling work roll is a core component of a cold rolling mill, mainly used for rolling metal plates at room temperature, and the material thinning and surface quality improvement are realized through roll system extrusion. At present, since the steel used to manufacture the cold rolling work roll has a high carbon content and a high degree of alloying, the diffusion rate of solute elements in the solid phase is slower than that in the liquid phase during the non-equilibrium solidification process of the steel. With the progress of solidification, the solute elements are redistributed, excluded to the front of the solid-liquid interface and enriched in the liquid phase, resulting in a higher concentration than the average composition, which is easy to form net-like or chain-like distributed liquid precipitated carbides. The existence of the net-like or chain-like distributed liquid precipitated carbides as stress concentration points is easy to become a fatigue crack source when stressed, which is easy to cause roll body peeling or roll breakage. Therefore, how to avoid the formation of net-like or chain-like distributed liquid precipitated carbides in the cold rolling work roll has become a technical problem to be solved at present. SUMMARY
[0003] The problem solved by the present application is how to avoid the formation of net-like or chain-like distributed liquid precipitated carbides in the cold rolling work roll.
[0004] To solve the above problems, the present application provides a preparation method of a cold rolling work roll, comprising: Step S1, first fire forging: heating the steel ingot to 1190-1210 DEG C, holding for 9-11 hours, and then performing first upsetting and drawing to obtain a first intermediate forging; wherein the final forging temperature of the first upsetting and drawing is 840-860 DEG C; Step S2, second fire forging: heating the first intermediate forging to 1190-1210 DEG C, holding for 9-11 hours, and then performing second upsetting and drawing to obtain a second intermediate forging; the final forging temperature of the second upsetting and drawing is 840-860 DEG C; Step S3, third fire forging: heating the second intermediate forging steel ingot to 1170-1180 DEG C, holding for 7-8 hours, and then performing third upsetting and drawing to obtain a third intermediate forging; the final forging temperature of the third upsetting and drawing is 740-760 DEG C; Step S4, performing post-forging heat treatment on the third intermediate forging to obtain a cold rolling work roll.
[0005] Optionally, in the step S4, the post-forging heat treatment on the third intermediate forging to obtain a cold rolling work roll comprises: Step S41, heating the third intermediate forging to 940-960 DEG C at a first heating rate, keeping for a first time, and then cooling to 250-300 DEG C, to obtain a fourth intermediate forging; Step S42, heating the fourth intermediate forging to 820-840 DEG C at a second heating rate, keeping for a second time, and then cooling to 720-740 DEG C at a first cooling rate, to obtain a fifth intermediate forging; Step S43, heating the fifth intermediate forging to 660-680 DEG C, keeping for a third time, and then air cooling to room temperature, to obtain the cold rolling work roll.
[0006] Optionally, in the step S41, the first heating rate is 50-80 DEG C / h.
[0007] Optionally, in the step S41, the first time is 5-8 h.
[0008] Optionally, in the step S42, the second heating rate is 80-120 DEG C / h, and the second time is 10-15 h.
[0009] Optionally, in the step S42, the first cooling rate is 20-50 DEG C / h.
[0010] Optionally, in the step S43, the third time is 14-20 h.
[0011] Optionally, the diameter of the cold rolling work roll is 350-900 mm.
[0012] Optionally, in the step S1, the material of the steel ingot is selected from 85Cr3MoV steel and 85Cr5MoV steel.
[0013] The application further provides a cold rolling work roll prepared by the method.
[0014] Compared with the related art, in the first fire forging to the second fire forging process, the heating temperature is set to 1190-1210 DEG C, and the holding time is extended to 9-11 h, due to the longer holding time, part of the coarse liquid precipitated carbide in the ingot is dissolved into the austenite matrix at high temperature; more importantly, the chromium-poor area around the carbide and the chromium-rich area in the carbide will produce a concentration gradient, driving the chromium atoms to diffuse from the area with high concentration to the area with low concentration, and after long time holding, the coarse liquid precipitated carbide will be gradually disconnected. In addition, by appropriately reducing the heating temperature (1170-1180 DEG C) and the final forging temperature (740-760 DEG C) in the last fire forging process, the liquid precipitated carbide which has been disconnected in the first fire forging to the second fire forging process can be further refined, so that the carbide is uniformly dispersed, thereby avoiding the appearance of the liquid precipitated carbide in the working roll. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 The metallographic structure picture of the cold rolling working roll prepared in Example 1 of the present application; Figure 2 The metallographic structure picture of the cold rolling working roll prepared in Comparative Example 1. DETAILED DESCRIPTION
[0016] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present application are shown in the drawings, it should be understood that the present application can be realized in various forms, and should not be interpreted as being limited to the embodiments described herein, on the contrary, these embodiments are provided in order to more thoroughly and completely understand the present application. It should be understood that the drawings and embodiments of the present application are only for exemplary purposes, and are not intended to limit the scope of protection of the present application.
[0017] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application.
[0018] As used herein, the term "includes" and its variants are open-ended, meaning that "includes but is not limited to"; the term "based on" means "based, at least in part, on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments." Related terms shall be construed accordingly. It should be noted that the terms "first", "second", and the like, as used herein do not have any specific meaning, but are used to distinguish a different object from another. In addition, the terms "first", "second" are used for description purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.
[0019] The preparation method of the cold rolling work roll provided by the embodiment of the present application comprises: Step S1, first fire forging: heating the steel ingot to 1190-1210 DEG C, holding for 9-11 hours, and then performing first upsetting and drawing to obtain a first intermediate forging; wherein the final forging temperature of the first upsetting and drawing is 840-860 DEG C; Step S2, second fire forging: heating the first intermediate forging to 1190-1210 DEG C, holding for 9-11 hours, and then performing second upsetting and drawing to obtain a second intermediate forging; the final forging temperature of the second upsetting and drawing is 840-860 DEG C; Step S3, third fire forging: heating the second intermediate forging steel ingot to 1170-1180 DEG C, holding for 7-8 hours, and then performing third upsetting and drawing to obtain a third intermediate forging; the final forging temperature of the third upsetting and drawing is 740-760 DEG C; Step S4, performing post-forging heat treatment on the third intermediate forging to obtain a cold rolling work roll.
[0020] In the first fire forging to the second fire forging process, the heating temperature is set to 1190 DEG C to 1210 DEG C, and the holding time is extended to 9h to 11h, due to the longer holding time, part of the coarse liquid precipitated carbide in the ingot is dissolved into the austenite matrix at high temperature, more importantly, the concentration gradient is generated between the chromium-poor area around the carbide and the chromium-rich area in the carbide, driving the chromium atoms to diffuse from the area with high concentration to the area with low concentration, after long time holding, the coarse liquid precipitated carbide will be gradually disconnected. In addition, by appropriately reducing the heating temperature (1170 DEG C to 1180 DEG C) and the final forging temperature (740 DEG C to 760 DEG C) in the last fire forging process, the liquid precipitated carbide which has been disconnected in the first fire forging to the second fire forging process can be further refined, so that the carbide is uniformly dispersed, thereby avoiding the liquid precipitated carbide in the working roll in a net or chain distribution.
[0021] In some embodiments of the present application, in the step S4, the third intermediate forging is subjected to the post-forging heat treatment to obtain the cold-rolled working roll, comprising: In step S41, the third intermediate forging is heated to 940 DEG C to 960 DEG C at a first heating rate, and then cooled to 250 DEG C to 300 DEG C to obtain a fourth intermediate forging; In step S42, the fourth intermediate forging is heated to 820 DEG C to 840 DEG C at a second heating rate, and then cooled to 720 DEG C to 740 DEG C at a first cooling rate to obtain a fifth intermediate forging; In step S43, the fifth intermediate forging is heated to 660 DEG C to 680 DEG C, and then air-cooled to room temperature to obtain the cold-rolled working roll.
[0022] In some embodiments of the present application, in the step S41, the first heating rate is 50 DEG C / h to 80 DEG C / h, and the first time is 5h to 8h.
[0023] In some embodiments of the present application, in the step S42, the second heating rate is 80 DEG C / h to 120 DEG C / h, the second time is 10h to 15h, and the first cooling rate is 20 DEG C / h to 50 DEG C / h.
[0024] In some embodiments of the present application, in the step S43, the third time is 14h to 20h.
[0025] In some embodiments of the present application, the diameter of the cold-rolled working roll is 350mm to 900mm.
[0026] In some embodiments of the present application, the material of the ingot is selected from 85Cr3MoV steel and 85Cr5MoV steel.
[0027] This invention also provides a cold rolling work roll, which is manufactured using the cold rolling work roll preparation method described above.
[0028] The present invention will be further described below with reference to specific embodiments.
[0029] Example 1 A1. First forging: The steel ingot is heated to 1200℃ and held for 10 hours, and then the first upsetting is performed to obtain the first intermediate forging; wherein the material of the steel ingot is 85Cr3MoV steel, and the final forging temperature of the first upsetting is 850℃.
[0030] A2. Second forging: The first intermediate forging is heated to 1200℃ and held for 10 hours, and then subjected to a second upsetting and drawing to obtain the second intermediate forging; the final forging temperature of the second upsetting and drawing is 850℃.
[0031] A3. Third forging: The second intermediate forging is heated to 1180℃ and held for 8 hours, and then subjected to a third upsetting and drawing to obtain the third intermediate forging; the final forging temperature of the third upsetting and drawing is 750℃.
[0032] A4. The third intermediate forging is heated to 950°C at a first heating rate, held at that temperature for a first time, and then cooled to 275°C to obtain the fourth intermediate forging; wherein the first heating rate is 65°C / h and the first time is 6.5h.
[0033] A5. The fourth intermediate forging is heated to 830°C at a second heating rate, held at that temperature for a second time, and then cooled to 730°C at a first cooling rate to obtain the fifth intermediate forging; wherein the second heating rate is 100°C / h, the second time is 12.5h, and the first cooling rate is 35°C / h.
[0034] A6. The five intermediate forgings are heated to 670°C, held at that temperature for a third time, and then air-cooled to room temperature to obtain the cold-rolled work roll. The third time is 17 hours, and the diameter of the cold-rolled work roll is 600 mm.
[0035] Example 2 A1. First forging: The steel ingot is heated to 1210℃ and held for 9 hours, and then the first upsetting is performed to obtain the first intermediate forging; wherein the material of the steel ingot is 85Cr5MoV steel, and the final forging temperature of the first upsetting is 850℃.
[0036] A2. Second forging: The first intermediate forging is heated to 1210℃ and held for 9 hours, and then subjected to a second upsetting and drawing to obtain the second intermediate forging; the final forging temperature of the second upsetting and drawing is 850℃.
[0037] A3. Third forging: The second intermediate forging is heated to 1170℃ and held for 7 hours, and then subjected to a third upsetting and drawing to obtain the third intermediate forging; the final forging temperature of the third upsetting and drawing is 750℃.
[0038] A4. The third intermediate forging is heated to 950°C at a first heating rate, held at that temperature for a first time, and then cooled to 275°C to obtain the fourth intermediate forging; wherein the first heating rate is 65°C / h and the first time is 6.5h.
[0039] A5. The fourth intermediate forging is heated to 830°C at a second heating rate, held at that temperature for a second time, and then cooled to 730°C at a first cooling rate to obtain the fifth intermediate forging; wherein the second heating rate is 100°C / h, the second time is 12.5h, and the first cooling rate is 35°C / h.
[0040] A6. The five intermediate forgings are heated to 670°C, held at that temperature for a third time, and then air-cooled to room temperature to obtain the cold-rolled work roll. The third time is 17 hours, and the diameter of the cold-rolled work roll is 600 mm.
[0041] Comparative Example 1 A1. First forging: The steel ingot is heated to 1200℃ and held for 2 hours, and then the first upsetting is performed to obtain the first intermediate forging; wherein the material of the steel ingot is 85Cr3MoV steel, and the final forging temperature of the first upsetting is 850℃.
[0042] A2. Second forging: The first intermediate forging is heated to 1200℃ and held for 2 hours, and then subjected to a second upsetting and drawing to obtain the second intermediate forging; the final forging temperature of the second upsetting and drawing is 850℃.
[0043] A3. Third forging: The second intermediate forging is heated to 1180℃ and held for 8 hours, and then subjected to a third upsetting and drawing to obtain the third intermediate forging; the final forging temperature of the third upsetting and drawing is 850℃.
[0044] A4. The third intermediate forging is heated to 950°C at a first heating rate, held at that temperature for a first time, and then cooled to 275°C to obtain the fourth intermediate forging; wherein the first heating rate is 65°C / h and the first time is 6.5h.
[0045] A5. The fourth intermediate forging is heated to 830°C at a second heating rate, held at that temperature for a second time, and then cooled to 730°C at a first cooling rate to obtain the fifth intermediate forging; wherein the second heating rate is 100°C / h, the second time is 12.5h, and the first cooling rate is 35°C / h.
[0046] A6. The five intermediate forgings are heated to 670°C, held at that temperature for a third time, and then air-cooled to room temperature to obtain the cold-rolled work roll. The third time is 17 hours, and the diameter of the cold-rolled work roll is 600 mm.
[0047] Experimental Example Metallographic characterization of the cold rolling work rolls obtained in Example 1 and Comparative Example 1 was performed, and the results are shown in the figure. Figure 1 and Figure 2 ,from Figure 1 It can be seen that no network or chain-like distribution of liquid carbides appeared in the cold rolling work rolls prepared in Example 1. Figure 2 It can be seen that the cold rolling work rolls prepared in Comparative Example 1 contain chain-like distributions of liquid carbides ( Figure 2 (White area in the middle)
[0048] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.
Claims
1. A method for preparing a cold-rolled work roll, characterized in that, include: Step S1, First forging: Heat the steel ingot to 1190℃ to 1210℃, hold for 9h to 11h, and then perform the first upsetting and drawing to obtain the first intermediate forging; wherein, the final forging temperature of the first upsetting and drawing is 840℃ to 860℃. Step S2, Second Forging: The first intermediate forging is heated to 1190°C to 1210°C and held for 9 to 11 hours, and then subjected to a second upsetting and drawing to obtain the second intermediate forging; the final forging temperature of the second upsetting and drawing is 840°C to 860°C. Step S3, Third Forging: The second intermediate forging steel ingot is heated to 1170°C to 1180°C and held for 7 to 8 hours, and then subjected to a third upsetting and drawing to obtain the third intermediate forging; the final forging temperature of the third upsetting and drawing is 740°C to 760°C. Step S4: Perform post-forging heat treatment on the third intermediate forging to obtain a cold-rolled work roll.
2. The method for preparing cold-rolled work rolls according to claim 1, characterized in that, In step S4, the post-forging heat treatment of the third intermediate forging to obtain a cold-rolled work roll includes: Step S41: Heat the third intermediate forging to 940°C to 960°C at a first heating rate, hold it at that temperature for a first time, and then cool it to 250°C to 300°C to obtain the fourth intermediate forging; Step S42: Heat the fourth intermediate forging to 820°C to 840°C at a second heating rate, hold it at that temperature for a second time, and then cool it to 720°C to 740°C at a first cooling rate to obtain the fifth intermediate forging; Step S43: Heat the five intermediate forgings to 660°C to 680°C, hold at that temperature for a third time, and air cool to room temperature to obtain the cold-rolled work roll.
3. The method for preparing cold-rolled work rolls according to claim 1, characterized in that, In step S41, the first heating rate is 50℃ / h to 80℃ / h.
4. The method for preparing cold-rolled work rolls according to claim 1, characterized in that, In step S41, the first time is 5 hours to 8 hours.
5. The method for preparing cold-rolled work rolls according to claim 1, characterized in that, In step S42, the second heating rate is 80℃ / h to 120℃ / h, and the second time is 10h to 15h.
6. The method for preparing cold-rolled work rolls according to claim 1, characterized in that, In step S42, the first cooling rate is 20℃ / h to 50℃ / h.
7. The method for preparing cold-rolled work rolls according to claim 1, characterized in that, In step S43, the third time period is 14h to 20h.
8. The method for preparing cold-rolled work rolls according to claim 1, characterized in that, The diameter of the cold rolling work roll is 350 mm to 900 mm.
9. The method for preparing cold-rolled work rolls according to claim 1, characterized in that, In step S1, the steel ingot is made of 85Cr3MoV steel and 85Cr5MoV steel.
10. A cold rolling work roll, characterized in that, It is manufactured using the method for preparing cold-rolled work rolls as described in any one of claims 1 to 9.