Rolling method of hard alloy N06625 in steckel mill
Through the two-fire heating and double-rolling process and the reasonable design of rolling method, the problem of breaking of cemented carbide N06625 in hot rolling production was solved, and hot rolling was achieved, which reduced production costs and met downstream process requirements.
Patent Information
- Application Number
- CN202510882795.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-28
- Publication Date
- 2025-09-05
AI Technical Summary
Cemented carbide N06625 is prone to fracture during hot rolling production and is difficult to roll into a coil, resulting in high production costs and inability to meet downstream process requirements.
The two-fire heating and double-rolling process is adopted, combined with the reasonable design of the rolling pass times and the thickness of the intermediate blank, and the rolling method of four-roll reversible rough rolling mill and double-stand furnace rolling mill, including slab in-furnace heating, open-blank rolling, surface grinding, rough rolling and furnace rolling, so as to achieve hot rolling of cemented carbide N06625.
The N06625 hot rolled coil with wide width and large rolls were successfully rolled on a dual-stand furnace rolling mill, reducing production costs and meeting the needs of downstream processing processes.
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Figure CN120587248A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of steel rolling, in particular to a method for rolling hard alloy N06625 in a Steckel mill. Background Art
[0002] Cemented carbide N06625 is a solid solution strengthened nickel-based alloy with excellent corrosion resistance. It is widely used in various fields such as high-end equipment manufacturing, petroleum and petrochemicals.
[0003] Cemented carbide N06625 suffers from characteristics such as easy solidification segregation, a narrow hot working range, and high deformation resistance. This makes it prone to fracture during hot rolling and difficult to roll into coils. Therefore, currently, N06625 is only available in sheet form as hot-rolled medium plates, resulting in high production costs and failing to meet the needs of downstream processes. Summary of the Invention
[0004] The object of the present invention is to provide a rolling method of cemented carbide N06625 in a Steckel mill, which can smoothly realize the hot rolling of cemented carbide N06625 into coils, thereby helping to reduce its production cost while easily meeting the needs of downstream processes.
[0005] The technical solution adopted by the present invention to solve the technical problem is: a rolling method of cemented carbide N06625 in a Steckel mill, comprising the following steps: S1, first rolling process; S1.1 Slab placement and primary heating: The thickness of the slab is 180±2mm. The slab is placed in a walking beam furnace for heating. The temperature ranges for each heating stage and the temperature range for exiting the furnace are set, and the dwell time is also set. S1.2 slab rolling: the slab is rolled using a four-roll reversing roughing mill to obtain a slab with a thickness of 120 ± 2 mm. S1.3 Surface grinding: Grind the surface cracks of the blank plate with a grinding rate of 3-6%; S2, the second rolling process: S2.1 Billet plate into the furnace and secondary heating: send the billet plate into the walking beam heating furnace for secondary heating and set the temperature range of each heating stage and the temperature range of the furnace, and set the furnace dwell time; S2.2 Rough rolling: The billet is rolled using a four-roll reversing rough rolling mill to obtain an intermediate billet with a thickness of 23±2 mm. S2.3 Steckel mill rolling: The intermediate slab is rolled using a twin-stand Steckel mill. The inlet and outlet coiling furnace temperatures are 1120±10°C. The thickness of the hot rolled strip obtained is in the range of 8±0.3mm. S2.4 layer cooling and coiling.
[0006] Preferably, the temperature range of each heating furnace section of the walking-beam heating furnace is: temperature range of the first heating section: 1120±20℃, temperature range of the second heating section: 1210±20℃; temperature range of the third heating section: 1220±20℃; temperature range of the equalizing section: 1220±20℃; temperature range of the furnace discharge: 1200±10℃; the residence time of the slab in the walking-beam heating furnace is not less than 200min.
[0007] Preferably, in step S1.2, when the slab is rolled using a four-roll reversible roughing mill, nine reciprocating rolling passes are adopted, with a rolling speed of ≤2.5 m / s for each pass and a reduction ratio of ≤5% for each pass; and at the same time, the vertical rolls have no side pressure.
[0008] Preferably, in step S1.3, the cracks on the upper and lower surfaces of the blank plate are first ground with a 16# coarse grinding wheel and then with a 20# grinding wheel, and the surface of the blank plate is inspected using a PT flaw detection method until there are no cracks on the upper and lower surfaces of the blank plate.
[0009] Preferably, in step S2.1, the temperature of each heating furnace section of the walking-beam heating furnace is set as follows: temperature range of the first heating section: 1120±20℃, temperature range of the second heating section: 1210±20℃; temperature range of the third heating section: 1220±20℃; temperature range of the equalizing section: 1240±20℃; temperature range of the furnace discharge: 1230±10℃; the residence time of the blank plate in the walking-beam heating furnace is not less than 200min.
[0010] Preferably, in step S2.2, when the billet plate is rolled using a four-roll reversible roughing mill: nine passes of reciprocating rolling are adopted, with a single pass reduction rate ≤20%, a rolling force ≤50,000 KN, a rolling speed ≤5.5 m / s, and no side pressure on the vertical rolls.
[0011] Furthermore, the reduction ratios from the first pass to the eighth pass gradually increase.
[0012] Preferably, in step S2.3, when rolling the intermediate slab using a double-stand Steckel mill, six-pass reciprocating rolling is adopted, with a single-pass reduction rate of ≤20%, a rolling force ≤48000 KN, and a rolling speed ≤10 m / s.
[0013] Furthermore, the reduction ratio from the first pass to the third pass gradually decreases.
[0014] Preferably, in step S2.4, when the steel strip passes through the laminar cooling area, cooling water is not supplied to the laminar cooling area; when the steel strip is coiled using a coiler, the coiler is tensioned after coiling 4 turns.
[0015] The beneficial effects of the present invention are as follows: the present invention solves the problem that cemented carbide N06625 is prone to fracture and difficult to be rolled into coils during hot rolling production by innovatively adopting a two-fire heating and double-rolling process rolling process, reasonably designing the number of rolling passes and the thickness of the intermediate billet, the reduction amount of the forward pass and other rolling methods, and successfully rolls out wide and heavy N06625 hot-rolled coils on a double-stand furnace coil mill; the rolling of cemented carbide N06625 into coils can help reduce the production and processing manufacturing costs of cemented carbide N06625, and at the same time, it is also beneficial for it to meet the requirements of downstream processing procedures. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some preferred embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0017] Figure 1 A schematic diagram of a flow chart of a specific embodiment of the present invention; Figure 2 This is a photo of a blank plate produced by slab rolling in a specific embodiment of the present invention; Figure 3 This is a photo of a blank plate after repair in a specific embodiment of the present invention; Figure 4 This is a photo of a N06625 hot-rolled coil produced in a specific embodiment of the present invention; DETAILED DESCRIPTION The following will be combined with specific embodiments and appendix Figure 1-4 The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the embodiments described are only some preferred embodiments of the present invention, not all embodiments. Those skilled in the art may make similar modifications without violating the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0018] The walking beam heating furnace, four-roll reversing roughing mill and double-stand Steckel mill involved in the present invention are all well-known mature technology products in the existing steel rolling technology field. Therefore, the specific structure and working principle of the walking beam heating furnace, four-roll reversing roughing mill and double-stand Steckel mill will not be described in detail here.
[0019] The present invention provides a method for rolling cemented carbide N06625 in a Steckel mill, wherein the method mainly adopts a two-fire heating and double-rolling process to realize coil rolling of cemented carbide N06625, and specifically comprises the following steps: S1, first rolling process; S1.1 Slabs are put into the furnace and heated with one fire: the slabs are put into the walking beam furnace for heating and the temperature range of each heating stage and the temperature range of the furnace are set, and the furnace residence time is also set; specifically, the thickness of the selected slab is 180±2mm. In this specific embodiment, the thickness of the slab is 180mm; the temperature ranges of each heating furnace section of the walking beam furnace are: the temperature range of the first heating section: 1120±20℃, the temperature range of the second heating section: 1210±20℃; the temperature range of the third heating section: 1220±20℃; the temperature range of the soaking section: 1220±20℃; the furnace discharge temperature range: 1200±10℃, and the furnace residence time of the slab in the walking beam furnace is not less than 200mi n, in actual application, it can be set between 200 and 300 minutes. In actual application, the length of each heating furnace section of the walking beam heating furnace is fixed. The walking beam heating furnace reasonably controls the stepping movement speed of the slab in the furnace according to the set dwelling time, and then realizes the time distribution of the slab in each furnace section; the temperature of each section, the furnace discharge temperature and the furnace dwelling time can be specifically: 1120℃, 1210℃, 1220℃, 1220℃, 1200℃ and 210 minutes. In this step, the furnace discharge temperature is raised to supplement the cooling of the slab in the subsequent rolling process, so that in the subsequent rolling process, the temperature of the slab is always maintained in a reasonable hot working range, which is conducive to the first hot rolling shaping of the slab; S1.2 slab rolling: The slab is rolled out of the furnace using a four-roll reversible roughing mill to obtain a slab. Specifically, nine reciprocating rolling passes are used, with a rolling speed of ≤2.5 m / s per pass and a reduction ratio of ≤5% per pass. At the same time, the vertical rolls are not subjected to side pressure, and the thickness of the obtained slab is within the range of 120 ± 2 mm. In this specific embodiment, by reasonably setting the reduction ratio per pass, the thickness of the final slab is 120 mm. S1.3 Surface grinding: Grind the surface cracks of the blank plate with a grinding rate of 3-6%. Specifically, first use a 16# coarse grinding wheel and then a 20# grinding wheel to grind the cracks on the upper and lower surfaces of the blank plate. Use the PT flaw detection method to detect the surface of the blank plate until there are no cracks on the upper and lower surfaces of the blank plate. The thickness of the blank plate after grinding is 115mm.
[0020] S2, the second rolling process: S2.1 Billet plate entering the furnace and secondary heating: send the billet plate into the walking beam heating furnace for secondary heating and set the temperature range of each heating stage of the walking beam heating furnace and the temperature range of the furnace discharge, and set the furnace residence time; specifically, the temperature setting of each heating furnace section of the walking beam heating furnace is as follows: the temperature range of the first heating section: 1120±20℃, the temperature range of the second heating section: 1210±20℃; the temperature range of the third heating section: 1220±20℃; the temperature range of the soaking section: 1240±20℃; the furnace discharge temperature range: 1230±10℃; the residence time of the billet in the walking beam heating furnace is not less than 200min, and can be set at 200~300m in actual application. in. In actual application, the length of each heating furnace section of the walking beam heating furnace is determined. The walking beam heating furnace reasonably controls the stepping movement speed of the billet plate in the furnace according to the set furnace dwelling time, and then realizes the time distribution of the billet in each furnace section; the temperature of each furnace section, the furnace discharge temperature and the furnace dwelling time can be specifically: 1120℃, 1210℃, 1220℃, 1240℃, 1230℃ and 220min; in this step, the furnace discharge temperature is raised to supplement the cooling of the billet plate in the subsequent rolling process, so that in the subsequent rolling process, the temperature of the billet plate is always maintained in a reasonable hot working range, which is conducive to the subsequent hot rolling shaping of the billet plate; S2.2 Rough rolling: The billet is rolled out of the furnace using a four-roll reversible roughing mill to obtain an intermediate billet. Specifically, the billet is rolled using a four-roll reversible roughing mill with nine reciprocating passes, a single-pass reduction ratio of ≤20%, a rolling force of ≤50,000 kN, a rolling speed of ≤5.5 m / s, and no side pressure from the vertical rolls. The thickness of the intermediate billet obtained is in the range of 23 ± 2 mm. In this specific embodiment, by reasonably controlling the single-pass reduction ratio and gradually increasing the reduction ratio from the first to the eighth pass, the thickness of the intermediate billet obtained is 23 mm. S2.3 Steckel mill rolling: The intermediate slab is rolled using a double-stand Steckel mill, and the temperatures of the inlet coiling furnace and the outlet coiling furnace are 1120±10℃. Specifically, six passes of reciprocating rolling are adopted, with a single pass reduction rate ≤20%, a rolling force ≤48000KN, and a rolling speed ≤10m / s. The thickness range of the obtained hot rolled strip is: 8±0.3mm. In this specific embodiment, the forward shift of the reduction amount is achieved by reasonably controlling the single pass reduction rate, and at the same time, the reduction rate from the first pass to the third pass is gradually reduced, and the thickness of the obtained rolled strip is 8mm.
[0021] S2.4 layer cooling and coiling; specifically, after the rolling of the strip after 8mm is completed, the laminar cooling device is used to cool the strip. When the strip passes through the laminar cooling area, the laminar cooling area does not supply cooling water. The lack of cooling water causes the temperature of the strip to drop slowly, thereby facilitating the coiling of the strip. The strip after passing through the laminar cooling area is coiled into a coil by a coiler. When the coiler is used to coil the steel strip, the coiler is tensioned after coiling 4 turns. After the steel strip is coiled 4 turns, its coiling stability is improved, so it is convenient for subsequent coiling.
[0022] The above method successfully realizes the coil rolling of cemented carbide N06625, which helps to reduce the production and processing costs of cemented carbide N06625 and also helps it meet the needs of downstream processing procedures.
[0023] The above rolling method is further described in detail below with reference to specific embodiments: S1, the first tying process; S1.1 Slabs are placed in the furnace and heated in one fire. The thickness of the slabs produced by the existing continuous casting machine is 180 mm. The thickness of the selected slabs was measured on site and was 181.88 mm thick and approximately 7500 mm long. The slabs were placed in a walking beam furnace for heating. The temperatures of the heating sections of the walking beam furnace were as follows: first heating section temperature 1130°C; second heating section temperature 1220°C; third heating section temperature 1230°C; soaking section temperature 1230°C; and furnace discharge temperature 1210°C. The dwell time was 230 minutes. S1.2 slab rolling: The slab is rolled using a four-roll reversible roughing mill to obtain a slab. The specific rolling parameters of slab rolling are shown in Table 1. Table 1 The first rolling process of the slab rolling procedure As shown in Table 1, after the slab is rolled nine times in the four-roll reversing roughing mill, the thickness of the final slab is 121.36 mm (hot value). S1.3 Surface grinding: Grind the surface cracks of the blank plate. First use a 16# coarse grinding wheel and then a 20# grinding wheel to grind the cracks on the upper and lower surfaces of the blank plate. Use the PT flaw detection method to detect the surface of the blank plate until there are no cracks on the upper and lower surfaces of the blank plate. The thickness of the blank plate after grinding is 114.93mm (cold value).
[0024] S2, the second rolling process: S2.1 Billet plate into the furnace and second fire heating: The temperatures of the heating sections of the walking beam furnace are: first heating section temperature 1130°C; second heating section temperature 1220°C; third heating section temperature 1230°C; soaking section temperature 1250°C; furnace discharge temperature 1240°C; and furnace dwell time 260 minutes. S2.2 Rough rolling: The billet is rolled out of the furnace using a four-roll reversing rough rolling mill to obtain an intermediate billet. The specific parameters for rolling into coils are shown in Table 2. Table 2 Second rolling process rough rolling regulations From the contents of Table 2 above, it can be seen that after the billet plate is rolled nine times by the four-roll reversing roughing mill, the thickness of the intermediate billet finally obtained is 23.34 mm (hot value); S2.3 Steckel mill rolling: The intermediate slab is rolled using a double-stand Steckel mill. The inlet and outlet coiling furnace temperatures are 1120°C. The specific finishing rolling parameters are shown in Table 3. Table 3 Second rolling process finishing rolling regulations As shown in Table 3, after six passes of the slab on the double-stand Steckel mill, the thickness of the final strip is 8.25 mm (hot value). S2.4 Layer cooling and coiling; specifically, after the strip is rolled, the strip is cooled by a laminar cooling device. When the strip passes through the laminar cooling area, no cooling water is supplied to the laminar cooling area. After passing through the laminar cooling area, the strip is coiled into a coil by a coiler. When the coiler is used to coil the steel strip, the coiler is stretched after coiling 4 turns, and the strip is coiled into a coil by the coiler.
[0025] In the present invention, “left” and “right” are relative positions used for the convenience of describing positional relationships, and therefore cannot be understood as absolute positions to limit the scope of protection.
[0026] Except for the technical features described in the specification, all other technical features are known technologies to those skilled in the art.
[0027] The above description, in conjunction with the accompanying drawings, details the preferred embodiments and examples of the present invention. However, the present invention is not limited to the above embodiments and examples. A person skilled in the art can make several improvements and modifications without departing from the concept of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A method for rolling cemented carbide N06625 in a Steckel mill, characterized in that: The following steps are involved: S1, first rolling process; S1.1 Slab placement and primary heating: The thickness of the slab is 180±2mm. The slab is placed in a walking beam furnace for heating. The temperature ranges for each heating stage and the temperature range for exiting the furnace are set, and the dwell time is also set. S1.2 slab rolling: the slab is rolled using a four-roll reversing roughing mill to obtain a slab with a thickness of 120 ± 2 mm. S1.3 Surface grinding: Grind the surface cracks of the blank plate with a grinding rate of 3-6%; S2, the second rolling process: S2.1 Billet plate into the furnace and secondary heating: send the billet plate into the walking beam heating furnace for secondary heating and set the temperature range of each heating stage and the temperature range of the furnace, and set the furnace dwell time; S2.2 Rough rolling: The billet is rolled using a four-roll reversing rough rolling mill to obtain an intermediate billet with a thickness of 23±2 mm. S2.3 Steckel mill rolling: The intermediate slab is rolled using a twin-stand Steckel mill. The inlet and outlet coiling furnace temperatures are 1120±10°C. The thickness of the hot rolled strip obtained is in the range of 8±0.3mm. S2.4 layer cooling and coiling.
2. The method for rolling cemented carbide N06625 in a Steckel mill according to claim 1, wherein In step S1.1, the temperature ranges of the heating furnace sections of the walking-beam heating furnace are as follows: the temperature range of the first heating section is 1120±20°C, the temperature range of the second heating section is 1210±20°C; the temperature range of the third heating section is 1220±20°C; the temperature range of the soaking section is 1220±20°C; the temperature range of the furnace discharge is 1200±10°C; and the residence time of the slab in the walking-beam heating furnace is not less than 200 minutes.
3. The method for rolling cemented carbide N06625 in a Steckel mill according to claim 1, wherein In step S1.2, when the slab is rolled using a four-roll reversible roughing mill, nine reciprocating rolling passes are used, with a rolling speed of ≤2.5 m / s for each pass and a reduction ratio of ≤5% for each pass; at the same time, there is no side pressure on the vertical rolls.
4. The method for rolling cemented carbide N06625 in a Steckel mill according to claim 1, wherein In step S1.3, the cracks on the upper and lower surfaces of the blank plate are first repaired with a 16# coarse grinding wheel and then with a 20# series grinding wheel, and the surface of the blank plate is inspected using a PT flaw detection method until there are no cracks on the upper and lower surfaces of the blank plate.
5. The method for rolling cemented carbide N06625 in a Steckel mill according to claim 1, wherein: In step S2.1, the temperature of each heating furnace section of the walking-beam heating furnace is set as follows: temperature range of the first heating section: 1120±20℃, temperature range of the second heating section: 1210±20℃; temperature range of the third heating section: 1220±20℃; temperature range of the equalizing section: 1240±20℃; temperature range of the furnace discharge: 1230±10℃; the residence time of the blank plate in the walking-beam heating furnace is not less than 200min.
6. The method for rolling cemented carbide N06625 in a Steckel mill according to claim 1, wherein In step S2.2, when the billet plate is rolled using a four-roll reversible roughing mill: nine passes of reciprocating rolling are adopted, with a single pass reduction rate ≤20%, a rolling force ≤50,000 kN, a rolling speed ≤5.5 m / s, and no side pressure on the vertical rolls.
7. The method for rolling cemented carbide N06625 in a Steckel mill according to claim 6, wherein: The reduction rate increases gradually from the first pass to the eighth pass.
8. The method for rolling cemented carbide N06625 in a Steckel mill according to claim 1, wherein: In step S2.3, when the intermediate slab is rolled using a double-stand Steckel mill, six-pass reciprocating rolling is adopted, with a single-pass reduction rate of ≤20%, a rolling force ≤48000 KN, and a rolling speed ≤10 m / s.
9. The method for rolling cemented carbide N06625 in a Steckel mill according to claim 8, wherein: The reduction rate gradually decreases from the first pass to the third pass.
10. The method for rolling cemented carbide N06625 in a Steckel mill according to claim 1, wherein: In step S2.4, when the steel strip passes through the laminar cooling area, cooling water is not supplied to the laminar cooling area; when the steel strip is coiled using a coiler, the coiler is tensioned after coiling 4 turns.