A method for manufacturing a high speed steel work roll

Abstract

The application discloses a preparation method of a high-speed steel work roll and belongs to the technical field of materials. The steps comprise the following steps: adopting material with component proportion meeting the alloy range of the outer layer material component of the high-speed steel work roll as raw material, adopting an electric arc furnace to smelt, smelting temperature of the outer layer being 1690-1720 DEG C, and pouring out of the furnace after reaching the requirement of the outer layer material component; fixing a middle core shaft on a cold-type tool base, surrounding the middle core shaft by a cold-type tool with the condition of circulating cooling liquid, pouring out the outer layer part, and processing into a composite blank of the outer layer+middle core shaft; adopting a hot isostatic pressing mode to process the poured-out blank; adopting an annealing mode to heat treat the poured-out blank; and processing until the finished product after the heat treatment is finished. The application prepares the work roll with high wear resistance, high organization grain size and high surface quality, improves the preparation technical level of the work roll in the hot rolling of the rolling industry, especially the work roll after the thin slab continuous casting and rolling, and improves the work roll efficiency and quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of materials, in particular to a preparation method of high-speed steel work roll. BACKGROUND

[0002] At present, high nickel chromium is generally used in the later stage of hot continuous rolling, the cycle is short, and the conventional high-speed steel has good wear resistance, but it cannot be used in the later stage of the rack due to insufficient accident resistance and crack propagation resistance, and the thin slab continuous casting and rolling can use high-speed steel material with better wear resistance because of no tail throwing and sticking steel, etc. In order to achieve the balance wear of carbide and matrix in high-speed steel matrix, it is necessary to ensure the dispersion distribution of carbide in the matrix, and the work roll in the finishing rolling stage needs to ensure good wear resistance and surface roughness resistance of the roll surface because of low rolling temperature and large deformation resistance during rolling.

[0003] Based on the above background, a material with high accident resistance suitable for the later stage of hot continuous rolling and good surface roughness is needed to be developed, and how to design a high wear-resistant material and how to determine the preparation method are urgent problems to be solved. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a preparation method of high-speed steel work roll, which prepares a work roll with high wear resistance, high organizational grain size and high surface quality, is suitable for rolling lines such as the later stage of hot continuous rolling, especially thin slab continuous casting and rolling, and is suitable for part of cold rolling rack, improves the preparation technology level of rolling roll in the rolling industry, especially in the later stage of thin slab continuous casting and rolling, and improves the efficiency and quality of rolling roll.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is:

[0006] A preparation method of high-speed steel work roll, comprising the following steps:

[0007] Step A: using materials with component proportion meeting the alloy range of the outer layer material of high-speed steel work roll as raw materials, using electric arc furnace for smelting, outer layer smelting temperature 1690-1720℃, reaching the outer layer material component requirement, pouring out of furnace;

[0008] Step B: fixing the middle core shaft on the cold type tool base, surrounding the middle core shaft with cold type tool with cooling liquid circulation condition, pouring out the outer layer part, and processing into the composite blank of outer layer+middle core shaft;

[0009] Step C: using hot isostatic pressing method to process the poured blank;

[0010] Step D: using annealing method to heat treat the poured blank;

[0011] Step E: processing until finished product after heat treatment.

[0012] The further improvement of the technical scheme of the present application is that in step A, the weight percentage of different alloys in the outer layer material composition is: C: 0.3-2.1%, Si: 0.4-1.5%, Mn: 0.3-1.3%, P≤0.10%, S≤0.08%, Cr: 2-10%, Ni: 0.5-3.0%, Mo: 0.5.0-20%, V: 0.1-15.0%, W: 0.1-10.0%, Nb: 0.1-1.0%, and the balance is Fe.

[0013] The further improvement of the technical scheme of the present application is that the alloy elements satisfy 5%≤Cr+Mo+W+V+Nb≤30%.

[0014] The further improvement of the technical scheme of the present application is that in step B, the outer layer of the core shaft is preheated before pouring, and the preheating temperature is 350-500°C.

[0015] The further improvement of the technical scheme of the present application is that in step B, the cold type tooling includes a U-shaped support provided with a base and a cooling pipeline arranged outside the support; the cooling pipeline includes a liquid inlet arranged at the bottom end of one side pipeline and a liquid outlet arranged at the top end of the other side pipeline.

[0016] The further improvement of the technical scheme of the present application is that in step B, the cooling medium is poured into the cold type tooling.

[0017] The further improvement of the technical scheme of the present application is that in step C, the temperature range of hot isostatic pressing is 1150-1180°C, the hot isostatic pressing pressure is 150-300MPa, and the duration is 1-3h.

[0018] The further improvement of the technical scheme of the present application is that in step D, the annealing temperature is 530-600°C, and the holding time is 50-70h.

[0019] Due to the adoption of the above technical scheme, the present application has achieved the following technical progress:

[0020] 1. The present application uses a special cold type tooling to chill the liquid steel, ensuring that the grain structure is small and uniform during solidification. At the same time, by using a core shaft, a layer of high-performance outer layer material is wrapped around the outer layer, and through preheating of the core shaft and etching of the outer layer steel, the purpose of metallurgical bonding of the bonding layer is achieved, ensuring good wear resistance of the outer layer while having accident resistance suitable for the working condition of the later stage of the rack.

[0021] 2. The present application also solves the problem of neck wear on the current market, and at the same time, higher strength of the neck performance is obtained.

[0022] 3、The present application further improves the strength of the bonding layer and the performance of the outer layer molten steel through the hot isostatic pressing treatment. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is the schematic diagram of the cold-type tooling in the present application;

[0024] Figure 2 is the base body structure picture after acid corrosion of the roll body working layer amplified 500 times in the present application;

[0025] Figure 3 is the metallographic structure of the product manufactured by the conventional centrifugal method;

[0026] 1, support, 2, cooling pipeline, 3, liquid inlet, 4, liquid outlet. DETAILED DESCRIPTION

[0027] The present application will be further described in detail below in combination with the drawings and examples:

[0028] A preparation method of a high-speed steel working roll, comprising the following steps:

[0029] Step A: adopt the material with the component proportion meeting the alloy range of the outer layer material component of the high-speed steel working roll as the raw material, adopt the electric arc furnace for smelting, the outer layer smelting temperature is 1690-1720℃, and the outer layer material component requirement is met to pour out and pour;

[0030] Step B: fix the middle core shaft on the cold-type tooling base, the middle core shaft is surrounded by the cold-type tooling, the cold-type tooling is provided with the condition of circulating cooling liquid, the outer layer part is poured out, and the composite blank of the outer layer+middle core shaft is processed; the middle core shaft is preheated before pouring the outer layer, and the preheating temperature is 350-500℃;

[0031] Step C: the poured blank is processed by the hot isostatic pressing mode, the hot isostatic pressing pressure is 150-300MPa, the temperature is 1150-1180℃, and the pressing time is 1-3h;

[0032] Step D: the poured blank is heat treated by annealing, the annealing temperature is 530-600℃, and the holding time is 50-70h;

[0033] Step E: process until the finished product after the heat treatment is finished.

[0034] The weight percentages of the different alloys of the outer layer material composition in step A are: C: 0.3-2.1%, Si: 0.4-1.5%, Mn: 0.3-1.3%, P≤0.10%, S≤0.08%, Cr: 2-10%, Ni: 0.5-3.0%, Mo: 0.5.0-20%, V: 0.1-15.0%, W: 0.1-10.0%, Nb: 0.1-1.0%, and the balance is Fe;

[0035] In order to make the high-speed steel working roll have a certain wear resistance during use, a certain amount of carbide needs to be formed. However, too much carbide will affect the accident resistance of the working roll. The content of carbide-forming elements needs to be limited. Therefore, the main alloying elements of the outer layer are 5%≤Cr+Mo+W+V+Nb≤30%.

[0036] like Figure 1 As shown, in step B, the cold type tooling includes a U-shaped bracket 1 provided with a base and a cooling pipeline 2 provided on the outside of the bracket; the cooling pipeline 2 includes a liquid inlet 3 provided at the bottom end of one side of the pipeline and a liquid outlet 4 provided at the top end of the other side of the pipeline; in order to achieve a chilling effect, a cooling medium such as cooling water is flushed into the cold type tooling to increase the cooling speed of the product.

[0037] Example 1

[0038] Scrap steel, Cr3 forging heads, ferrovanadium, ferromolybdenum, ferrovanadium powder, Nb iron powder and ferrotungsten powder are used as raw materials and smelted in an electric arc furnace to achieve the designed composition range: C: 0.65%, Si: 0.53%, Mn: 0.65%, P: 0.001%, S: 0.001%, Cr: 4.12%, Ni: 0.96%, Mo: 10.12%, V: 12.35%, Nb: 0.53%, W: 3.98%, and the balance is Fe. Melting is carried out at a temperature of 1690℃. After the composition meets the standard, the temperature is raised to 1710℃ and then taken out of the furnace. Static pouring is carried out after the furnace is taken out, and a forged steel shaft with a core of 92CrMo is poured in. The box is unpacked 60 hours after the pouring is completed. After unpacking, the blank is subjected to rough polishing, the paint and surface black skin are removed, and the roller blank is wrapped with low-alloy steel and welded and sealed. After sealing, it is loaded into the hot isostatic pressing furnace for hot pressing. The hot isostatic pressing pressure is 200MPa, the hot pressing temperature is 1160℃, and the hot pressing time is 1.5h. After the hot pressing is completed, the roller body is blown, cooled to 500℃, and then loaded into the furnace for annealing at 530℃ and kept warm for 50h. After the heat treatment, it undergoes semi-finishing, testing, and finishing testing until it is finished.

[0039] Example 2

[0040] The waste steel, Cr3 forging material head, vanadium iron, molybdenum iron, vanadium iron powder, Nb iron powder and tungsten iron powder are used as raw materials, and an electric arc furnace is used for smelting, so as to reach the designed component range: C: 0.96%, Si: 0.59%, Mn: 0.69%, P: 0.002%, S: 0.002%, Cr: 4.13%, Ni: 0.93%, Mo: 10.05%, V: 8.35%, Nb: 0.23%, W: 3.86%, and the balance is Fe. The smelting is carried out at a temperature of 1693 ℃, the temperature is increased to 1712 ℃ after the components reach the standard, and then the furnace is discharged, and static casting is carried out. The forged steel shaft with a core of 92CrMo is poured into, the box is opened after 60 h, rough machining is carried out after the box is opened, the paint and the surface black skin are removed, the low alloy steel is used to wrap and weld the roll blank, the roll blank is sealed after sealing, and is loaded into a hot isostatic pressing furnace body for hot pressing. The hot isostatic pressing pressure is 250 MPa, the hot pressing temperature is 1163 ℃, and the hot pressing time is 1.8 h. After the hot pressing is completed, the roll body is blown, and is loaded into the furnace for annealing after being cooled to 505 ℃. The annealing temperature is 535 ℃, and the heat preservation time is 55 h. After the heat treatment is completed, semi-finishing, detection, finishing and detection are carried out until the finished product.

[0041] Example 3

[0042] The waste steel, Cr3 forging material head, vanadium iron, molybdenum iron, vanadium iron powder, Nb iron powder and tungsten iron powder are used as raw materials, and an electric arc furnace is used for smelting, so as to reach the designed component range: C: 0.96%, Si: 0.59%, Mn: 0.69%, P: 0.002%, S: 0.002%, Cr: 4.13%, Ni: 0.93%, Mo: 10.05%, V: 8.35%, Nb: 0.23%, W: 3.86%, and the balance is Fe. The smelting is carried out at a temperature of 1693 ℃, the temperature is increased to 1712 ℃ after the components reach the standard, and then the furnace is discharged, and static casting is carried out. The forged steel shaft with a core of 92CrMo is poured into, the box is opened after 60 h, rough machining is carried out after the box is opened, the paint and the surface black skin are removed, the low alloy steel is used to wrap and weld the roll blank, the roll blank is sealed after sealing, and is loaded into a hot isostatic pressing furnace body for hot pressing. The hot isostatic pressing pressure is 250 MPa, the hot pressing temperature is 1163 ℃, and the hot pressing time is 1.8 h. After the hot pressing is completed, the roll body is blown, and is loaded into the furnace for annealing after being cooled to 505 ℃. The annealing temperature is 535 ℃, and the heat preservation time is 55 h. After the heat treatment is completed, semi-finishing, detection, finishing and detection are carried out until the finished product.

[0043] Example 4

[0044] The waste steel, Cr3 forging material head, vanadium iron, molybdenum iron, vanadium iron powder, Nb iron powder and tungsten iron powder are used as raw materials, and an electric arc furnace is used for smelting, so as to reach the designed component range: C: 0.93%, Si: 0.67%, Mn: 0.65%, P: 0.0016%, S: 0.0014%, Cr: 4.15%, Ni: 0.73%, Mo: 8.61%, V: 7.35%, Nb: 0.29%, W: 3.89%, and the balance is Fe. The smelting is carried out at a temperature of 1693 ℃, the temperature is increased to 1715 ℃ after the components reach the standard, and then the furnace is discharged, and static casting is carried out. The forged steel shaft with a core of 92CrMo is poured into, the box is opened after 57h, rough machining is carried out after the box is opened, the paint and the surface black skin are removed, the low alloy steel is used to wrap and weld the roll blank, the roll blank is sealed after sealing, and is loaded into a hot isostatic pressing furnace body for hot pressing. The hot isostatic pressing pressure is 150 MPa, the hot pressing temperature is 1180 ℃, and the hot pressing time is 1.4h. After the hot pressing is completed, the roll body is blown, and is loaded into the furnace for annealing after being cooled to 501 ℃. The annealing temperature is 539 ℃, and the heat preservation time is 70h. After the heat treatment is completed, semi-finishing, detection, finishing and detection are carried out until the finished product.

[0045] Example 5

[0046] The waste steel, Cr3 forging material head, vanadium iron, molybdenum iron, vanadium iron powder, Nb iron powder and tungsten iron powder are used as raw materials, and an electric arc furnace is used for smelting, so as to reach the designed component range: C: 0.53%, Si: 0.61%, Mn: 0.63%, P: 0.0012%, S: 0.0012%, Cr: 4.11%, Ni: 0.71%, Mo: 8.51%, V: 7.31%, Nb: 0.21%, W: 3.81%, and the balance is Fe. The smelting is carried out at a temperature of 1691 ℃, the temperature is increased to 1711 ℃ after the components reach the standard, and then the furnace is discharged, and static casting is carried out. The forged steel shaft with a core of 92CrMo is poured into, the box is opened after 53h, rough machining is carried out after the box is opened, the paint and the surface black skin are removed, the low alloy steel is used to wrap and weld the roll blank, the roll blank is sealed after sealing, and is loaded into a hot isostatic pressing furnace body for hot pressing. The hot isostatic pressing pressure is 280 MPa, the hot pressing temperature is 1151 ℃, and the hot pressing time is 1h. After the hot pressing is completed, the roll body is blown, and is loaded into the furnace for annealing after being cooled to 513 ℃. The annealing temperature is 585 ℃, and the heat preservation time is 53h. After the heat treatment is completed, semi-finishing, detection, finishing and detection are carried out until the finished product.

[0047] Example 6

[0048] Scrap steel, Cr3 forging heads, ferrovanadium, ferromolybdenum, ferrovanadium powder, Nb iron powder and ferrotungsten powder are used as raw materials and smelted in an electric arc furnace to achieve the designed composition range: C: 0.91%, Si: 0.66%, Mn: 0.64%, P: 0.0015%, S: 0.0016%, Cr: 4.13%, Ni: 0.69%, Mo: 9.13%, V: 7.39%, Nb: 0.25%, W: 3.51%, and the balance is Fe. Melting is carried out at a temperature of 1703℃. After the composition meets the standard, the temperature is raised to 1720℃ and then taken out of the furnace. After being taken out of the furnace, static pouring is performed, and a forged steel shaft with a core of 92CrMo is poured in. After pouring, the box is unpacked 56 hours after completion. After unpacking, the blank is subjected to rough polishing, the paint and surface black skin are removed, and the roller blank is wrapped with low-alloy steel and welded and sealed. After sealing, it is loaded into the hot isostatic pressing furnace for hot pressing. The hot isostatic pressing pressure is 300MPa, the hot pressing temperature is 1150℃, and the hot pressing time is 3h. After the hot pressing, the roller body is blown, cooled to 511℃, and then loaded into the furnace for annealing at 600℃ and kept warm for 57h. After the heat treatment, it undergoes semi-finishing, testing, and finishing testing until it is finished.

[0049] Example 7

[0050] Example 7 is a control example, in which the outer layer material is the same as that of Example 1, the core material is ductile iron, and it is produced by conventional centrifugation.

[0051] The products of Examples 1 to 7 were subjected to tensile mechanical property testing of the samples. The performance testing was carried out in accordance with the national standard GB / T228. The test results are shown in Table 1.

[0052] Table 1 Example product performance test results

[0053]

[0054] like Figure 2 、 3 The metallographic pictures shown are Figure 2 This is a picture of the matrix structure of the roller working layer after acid corrosion, magnified 500 times. Figure 3 It is a product organization produced by conventional centrifugal process.

[0055] Performance testing of the specially designed high-speed steel and comparisons with the examples show that the developed rolls exhibit excellent wear resistance and exceptional roll neck strength, significantly improving wear resistance compared to the ductile iron used in conventional centrifugal rolls. Furthermore, the roll barrel exhibits superior thermal fatigue resistance to conventional high-alloy high-speed steel. Thermal wear tests show that the developed high-speed steel work rolls exhibit superior on-machine wear plus off-machine grinding compared to Example 7.

[0056] According to the performance detection result and the metallographic picture, it is concluded that the developed high-speed steel roller has good wear resistance, the neck strength is higher than that of conventional nodular iron material, the roller body has high wear resistance and the core has high toughness, meanwhile, the grain is fine and the anti-accident performance is good.

[0057] In conclusion, the working roller with high wear resistance, high grain size and high surface quality is prepared, which is suitable for hot continuous rolling, especially for the later stage rack of thin slab continuous casting and rolling, and is suitable for part cold rolling rack, improves the roller preparation technical level of hot rolling, especially for the later stage of thin slab continuous casting and rolling, and improves the efficiency and quality of the roller.

Claims

1. A method for preparing a high-speed steel work roll, characterized in that: The following steps are involved: Step A: Using materials with a composition ratio that meets the alloy range of the outer layer material composition of the high-speed steel work roll as raw materials, smelting is carried out in an electric arc furnace, and the outer layer melting temperature is 1690-1720°C. When the outer layer material composition requirements are met, it is taken out of the furnace and cast; In step A, the weight percentages of different alloys in the outer layer material composition are: C: 0.3-2.1%, Si: 0.4-1.5%, Mn: 0.3-1.3%, P≤0.10%, S≤0.08%, Cr: 2-10%, Ni: 0.5-3.0%, Mo: 8.51-20%, V: 0.1-15.0%, W: 0.1-10.0%, Nb: 0.1-1.0%, and the balance is Fe; the alloying elements satisfy 5%≤Cr+Mo+W+V+Nb≤30%; Step B: Fix the central core shaft on the cold tooling base. The central core shaft is surrounded by a cold tooling with cooling liquid circulation conditions. The outer layer is cast to form a composite blank of the outer layer + central core shaft. The cold type tooling comprises a U-shaped bracket (1) provided with a base and a cooling pipeline (2) provided on the outside of the bracket; the cooling pipeline (2) comprises a liquid inlet (3) provided at the bottom end of one side of the pipeline and a liquid outlet (4) provided at the top end of the other side of the pipeline; a cooling medium is injected into the cold type tooling; The outer layer of the core shaft is preheated before pouring, and the preheating temperature is 350-500℃; Step C: The cast blank is subjected to pressure processing by hot isostatic pressing; The temperature range of hot isostatic pressing is 1150-1180°C, the pressure of hot isostatic pressing is 150-300 MPa, and the duration is 1-3 hours; Step D: The cast blank is heat treated by annealing at a temperature of 530-600°C for 50-70 hours; Step E: After the heat treatment is completed, the product is processed until it is finished.

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