Manufacturing method of edging roller for rolling track beam

Abstract

The invention discloses a manufacturing method of an edging roller for rail beam rolling, which belongs to the technical field of rail beam rolling, and comprises the following steps: S1, smelting: sequentially adding pig iron, scrap steel, material heads and alloy into an intermediate frequency furnace according to the requirements of chemical components of an outer layer and a core part of the edging roller made of a high-speed steel material to obtain qualified molten steel; the tapping temperature of the outer layer molten steel is controlled to be 1550-1600 DEG C, and the tapping temperature of the core molten steel is controlled to be 1500-1560 DEG C; s2, centrifugal casting is conducted, specifically, the rotating speed of a centrifugal machine is controlled to be 800-900 r / min, and 0.5-1.0 kg / t of glass slag is added along with flow when the outer layer is cast; the interval time between the outer layer and the core part is controlled to be 5-10 min, and after the time is up, core part molten steel is poured; s3, heat treatment; s4, finish turning; and S5, assembling. The problems that the hole pattern of the edging roller for rolling the rail beam is not wear-resistant, the edge falls off, and the non-transmission end journal is broken are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of rail beam rolling, in particular to a manufacturing method of an edging roll for rail beam rolling. Background Art

[0002] In the prior art, the edging rolls used for rail beam rolling are mainly made of semi-steel material, but there are some problems in actual production. Since different pass shapes need to be opened on the edging roll and the pass depth is relatively large, it is difficult for the traditional static casting semi-steel material to meet the use requirements of the edging roll, and problems such as non-wear-resistant pass shapes and edge chipping are likely to occur during the rolling process. At the same time, due to the relatively small diameter of the non-driving end journal of the edging roll, there are porosity defects in the casting semi-steel, and the journal is extremely prone to fracture during the rolling process, resulting in rolling accidents. With the development of high-speed railways and rail transit, the quality requirements for steel rails are getting higher and higher, and the roll profile retention ability and wear resistance of the rolls need to be improved. However, the conventional semi-steel material can no longer meet the application requirements of rail beam rolling, which seriously restricts the development of rail beam plants. Therefore, it is urgent to improve the edging roll for rail beam rolling to solve the above problems to meet the higher requirements for rolls put forward by rail rolling. For this purpose, new materials and manufacturing processes need to be adopted to improve the wear resistance, thermal crack resistance and accident resistance of the edging roll. By means of reasonable design of the structural form of the edging roll, optimization of the material ratio and heat treatment process and other technical means, the problems existing in the existing edging roll can be effectively solved, so as to meet the higher requirements for rolls put forward by rail beam rolling. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a manufacturing method of an edging roll for rail beam rolling, and solve the problems of non-wear-resistant pass shapes, edge chipping and fracture of the non-driving end journal of the edging roll for rail beam rolling.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A manufacturing method of an edging roll for rail beam rolling, comprising the following steps:

[0006] S1. Melting:

[0007] S11. Add pig iron, scrap steel, billet heads and alloys into the intermediate frequency furnace in sequence according to the chemical composition requirements of the outer layer and the core of the high-speed steel material edging roll to obtain qualified molten steel;

[0008] The chemical composition of the outer layer and the mass percentage content of each component are: C 1.5-2%, Si 0.5-1.0%, Mn 0.6-1.2%, Cr 4.0-6.0%, Ni 1.0-2.0%, Mo 3.0-6.0%, V 2.0-4.0, W 2.0-4.0, and the rest are Fe and unavoidable impurities;

[0009] The chemical composition of the core part and the mass percentage of each component are as follows: C 0.8 - 1.5%, Si 1.2 - 1.8%, Mn 0.5 - 1.0%, Cr ≤ 0.3%, Ni ≤ 0.5%, Mo ≤ 0.5%.

[0010] In S12, the tapping temperature of the molten steel for the outer layer is controlled at 1550 - 1600°C, and the tapping temperature of the molten steel for the core part is controlled at 1500 - 1560°C for rapid tapping.

[0011] S2. Centrifugal casting:

[0012] In S21, the rotational speed of the centrifuge is controlled at 800 - 900 r / min. When casting the outer layer, 0.5 - 1.0 kg / t of glass slag is added with the flowing molten steel.

[0013] In S22, the interval time between the outer layer and the core part is controlled at 5 - 10 min. After the time is up, the molten steel for the core part is poured in.

[0014] S3. Heat treatment:

[0015] After rough machining of the roll ring, high-temperature quenching and multiple temperings are carried out. The quenching temperature is controlled at 1000 - 1100°C, and the tempering temperature is controlled at 540 - 580°C.

[0016] S4. Precision turning:

[0017] The roll sleeve of the edging roll is machined to the finished product size.

[0018] S5. Assembly:

[0019] In S51, the roll sleeve of the edging roll is put into a low-temperature resistance furnace and preheated to 250 - 350°C for heat preservation for 10 - 20 h.

[0020] In S52, after the roll sleeve of the edging roll is preheated and heat-preserved, it is quickly taken out of the furnace and placed on the hot-fitting pit.

[0021] In S53, the processed roll shaft of the edging roll is lifted by a crane and hot-fitted through the roll sleeve of the edging roll.

[0022] After hot-fitting, slow cooling is carried out, and the slow cooling temperature ≤ 50°C.

[0023] A further improvement of the technical solution of the present invention lies in:

[0024] In S11, the outer layer and the core part of the roll sleeve are smelted in different intermediate frequency furnaces, and according to their respective smelting time and tapping time, different power-on times are controlled.

[0025] A further improvement of the technical solution of the present invention lies in:

[0026] In S3, the quenching temperature is controlled at 1080 - 1100 °C, and the holding time is controlled at 8 - 12 h; the tempering holding time is controlled at 30 - 50 h, and the number of tempering times is controlled at 3 times.

[0027] A further improvement of the technical solution of the present invention lies in:

[0028] In S4, it is processed to the finished product size, where the inner hole is precision ground by a grinding machine, and the inner hole size has an interference fit with the roll shaft of the edging roll, and the interference amount is controlled at 1.0 - 1.2‰.

[0029] A further improvement of the technical solution of the present invention lies in:

[0030] In S52, after the edging roll is preheated and held, it is taken out of the furnace within 8 minutes and placed on the hot charging pit. The hot charging pit is circular, the pit mouth diameter is φ700 mm, the pit depth is ≥2 m, and the whole pit is of reinforced concrete structure.

[0031] A further improvement of the technical solution of the present invention lies in:

[0032] In S53, for the processed roll shaft of the edging roll, the assembly part is processed by a grinding machine, and the processing times are matched with the roll sleeve of the edging roll, and the interference amount is controlled at 1.0 - 1.2‰.

[0033] A further improvement of the technical solution of the present invention lies in:

[0034] In S54, after the hot charging is completed, the roll sleeve of the edging roll is wrapped with aluminosilicate needle felt. After natural cooling to 50 °C, the aluminosilicate needle felt is removed and packaged and stored in the warehouse.

[0035] A further improvement of the technical solution of the present invention lies in:

[0036] The obtained edging roll has a roll body hardness of HSD80 - 90, a roll diameter hardness of 40 - 50 HSD, and a journal strength of ≥800 Mpa.

[0037] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is:

[0038] 1. The novel high-speed steel material edging roll prepared by the present invention has high journal strength, good toughness, good red hardness, good wear resistance and good accident resistance of the roll body, solves the problems of non-wear resistance of the pass of the edging roll, block dropping at the edge of the pass and journal fracture, and the on-line time is extended by 3 - 5 times compared with the conventional semi-steel material.

[0039] 2. The present invention manufactures a novel high-speed steel roll sleeve and a forged steel material roll shaft respectively, and realizes high red hardness and wear resistance of the roll body and high strength and high toughness of the roll diameter through interference fitting. Specific Embodiments

[0040] The present invention will be further described in detail below in conjunction with embodiments:

[0041] The chemical composition of the outer layer of the edging roll for rail beam rolling and the mass percentage content of each component are: C 1.5 - 2%, Si 0.5 - 1.0%, Mn 0.6 - 1.2%, Cr 4.0 - 6.0%, Ni 1.0 - 2.0%, Mo 3.0 - 6.0%, V 2.0 - 4.0, W 2.0 - 4.0, and the rest are Fe and unavoidable impurities.

[0042] The chemical composition of the core of the edging roll for rail beam rolling and the mass percentage content of each component are: C 0.8 - 1.5%, Si 1.2 - 1.8%, Mn 0.5 - 1.0%, Cr ≤ 0.3%, Ni ≤ 0.5%, Mo ≤ 0.5%.

[0043] A manufacturing method of an edging roll for rail beam rolling includes the following steps:

[0044] S1. Melting:

[0045] S11. Add pig iron, scrap steel, ingot heads, alloys, etc. into the intermediate frequency furnace in sequence according to the requirements of the chemical composition of the outer layer and the core of the edging roll made of high-speed steel material to obtain qualified molten steel for the inner and outer layers;

[0046] The outer layer and the core of the roll sleeve are smelted in different intermediate frequency furnaces respectively, and the different power-on times are controlled according to their respective smelting time and tapping time;

[0047] S12. Control the tapping temperature of the outer layer molten steel at 1550 - 1600 °C, and control the tapping temperature of the core molten steel at 1500 - 1560 °C and quickly tap the furnace;

[0048] S2. Centrifugal casting:

[0049] S21. Control the rotation speed of the centrifuge at 800 - 900 r / min. When casting the outer layer, add 0.5 - 1.0 kg / t of glass slag with the flow;

[0050] S22. Control the interval time between the outer layer and the core at 5 - 10 min. After the time is up, pour the core molten steel;

[0051] S3. Heat treatment:

[0052] After rough machining of the roll ring, perform high-temperature quenching + multiple temperings. Control the quenching temperature at 1000 - 1100 °C and the tempering temperature at 540 - 580 °C;

[0053] Control the quenching temperature at 1080 - 1100 °C, the holding time at 8 - 12 h; control the tempering holding time at 30 - 50 h, and the number of tempering times at 3 times.

[0054] S4. Precision turning:

[0055] Process the edging roll sleeve to the finished size;

[0056] Process to the finished size, where the inner hole is finely ground by a grinding machine, and the inner hole size should have an interference fit with the edging roll shaft, and the interference amount is controlled at 1.0 - 1.2‰.

[0057] S5. Assembly:

[0058] S51 Put the edging roll sleeve into a low-temperature resistance furnace, preheat it to 250 - 350°C, and keep it warm for 10 - 20 h;

[0059] After the edging roll sleeve is preheated and kept warm, quickly take it out of the furnace and place it on the hot-fitting pit;

[0060] After the edging roll is preheated and kept warm, take it out of the furnace within 8 minutes and place it on the hot-fitting pit. The hot-fitting pit is circular, the diameter of the pit mouth is φ700mm, the depth of the pit is ≥2m, and the whole pit is of reinforced concrete structure.

[0061] S53 Use a crane to lift the processed edging roll shaft and implement hot-fitting through the edging roll sleeve;

[0062] For the processed edging roll shaft, the assembly part is processed by a grinding machine, and the processing times match the edging roll sleeve, and the interference amount is controlled at 1.0 - 1.2‰.

[0063] S54 After hot-fitting, perform slow cooling, and the slow cooling temperature ≤50°C;

[0064] After hot-fitting is completed, wrap the edging roll sleeve with aluminosilicate needled felt. After it is naturally cooled to 50°C, the aluminosilicate needled felt can be removed and it can be packaged and stored in the warehouse.

[0065] The comparison between the present invention and the conventional semi-steel material indexes is shown in Table 1 as follows:

[0066] Table 1 Comparison of the performance between the conventional semi-steel material and the combined high-speed steel

[0067] Hardness / HSD Single rolling volume / t Shaft breakage accident rate Conventional semi-steel material 45-50 2000-3000 10％ Composite high-speed steel 80-90 6000-10000 0

[0068] The hardness of the roll body of the prepared edging roll is HSD80 - 90, the hardness of the roll diameter is 40 - 50HSD, and the strength of the journal is ≥800 Mpa.

[0069] Example

[0070] 1. The roll shaft can select 42CrMo forged steel material with very good strength and toughness.

[0071] 2. The roll sleeve is made of composite materials and produced by centrifugal casting process. The outer layer is made of a new type of high-speed steel material with high wear resistance and high hardness, ensuring a sufficient thickness of the working layer with high wear resistance. The core material is made of graphite steel material, which has certain strength, toughness and plasticity to resist the stress caused by hot installation.

[0072] The components and their weight percentages of the outer layer and the core of an edging roll for rail beam rolling are shown in Table 2 as follows:

[0073] Table 2 Components and their weight percentages (wt%) of the outer layer and the core of an edging roll for rail beam rolling

[0074] C Si Mn Cr Ni Mo V W Working layer 1.7 0.80 0.86 5.05 1.44 4.50 3.0 3.0 Inner layer 1.25 1.80 0.80 0.20 0.50 0.30

[0075] A manufacturing method of an edging roll for rail beam rolling includes the following steps:

[0076] S1. Melting:

[0077] S11. Add pig iron, scrap steel, billet heads, alloys, etc. into different medium-frequency furnaces in sequence according to the requirements of the chemical compositions of each part of the inner and outer layers of the edging roll made of the new type of high-speed steel material to obtain qualified molten steel for the inner and outer layers;

[0078] S12. Control the tapping temperature of the outer layer molten steel at 1580°C and the tapping temperature of the core molten steel at 1550°C and tap quickly;

[0079] S2. Centrifugal casting:

[0080] S21. Control the rotation speed of the centrifuge at 880 r / min. When casting the outer layer, add 1.0 kg / t of glass slag with the molten metal;

[0081] S22. Control the interval time between the outer layer and the core at 10 min. After the time is up, pour the core molten steel;

[0082] S3. Heat treatment:

[0083] After rough machining of the roll ring, perform high-temperature quenching + 3 times of tempering. Control the quenching temperature at 1100°C and the tempering temperature at 560°C.

[0084] S4. Finish turning:

[0085] Machine the roll sleeve of the edging roll to the finished product size. The inner hole is finely ground by a grinding machine, and the inner hole size should have an interference fit with the roll shaft of the edging roll. The interference amount is controlled at 1.2‰.

[0086] S5. Assembly:

[0087] S51. Put the roll sleeve of the edging roll into a low-temperature resistance furnace, preheat it to 320°C and keep it warm for 20 h;

[0088] After preheating and heat preservation of the edging roll sleeve, quickly take it out of the furnace and place it on the hot charging pit;

[0089] S53 Use a crane to lift the processed edging roll shaft. The assembly part of the roll shaft is processed by a grinding machine. The roll shaft quickly passes through the edging roll sleeve for hot assembly;

[0090] After hot assembly, wrap the entire roll sleeve with aluminosilicate needled felt for slow cooling. The aluminosilicate needled felt can be removed when the slow cooling temperature ≤ 50°C.

[0091] In summary, the prepared neck of the edging roll for rail beam rolling of the present invention has high strength, good toughness, good accident resistance, good red hardness of the roll body and good wear resistance. It solves the problems of original neck fracture, chipping of the roll body pass and non-wear resistance. The single rolling amount is increased from 2000 - 3000t to 6000 - 10000t.

Claims

1. A method for manufacturing an edge rolling roller for rail beam rolling, characterized in that: The following steps are involved: S1. Melting: S11 adds pig iron, scrap steel, material head and alloy into the medium frequency furnace in order according to the requirements of the chemical composition of the outer layer and the core of the high-speed steel edge rolling roller to obtain qualified molten steel; The chemical composition of the outer layer and the mass percentage of each component are C1.5-2%, Si 0.5-1.0%, Mn 0.6-1.2%, Cr 4.0-6.0%, Ni1.0-2.0%, Mo 3.0-6.0%, V2.0-4.0, W2.0-4.0, and the rest are Fe and unavoidable impurities; The chemical composition of the core and the mass percentage of each component are C 0.8-1.5%, Si 1.2-1.8%, Mn 0.5-1.0%, Cr ≤0.3%, Ni ≤0.5%, Mo ≤0.5%; S12 The temperature of the outer molten steel out of the furnace is controlled at 1550-1600℃, and the temperature of the core molten steel out of the furnace is controlled at 1500-1560℃ for rapid outflow; S2. Centrifugal casting: The speed of S21 centrifuge is controlled at 800-900r / min. When pouring the outer layer, 0.5-1.0kg / t glass slag is added along the flow; The interval between the outer layer and the core of S22 is controlled to be 5-10 minutes. After the time is up, pour the core molten steel; S3. Heat treatment: After rough machining, the roller ring is subjected to high temperature quenching and multiple tempering. The quenching temperature is controlled at 1000-1100℃, and the tempering temperature is controlled at 540-580℃. S4, Finishing Turning: Processing the edge rolling roll sleeve to the finished product size; S5. Assembly: S51 put the edge rolling roller set into a low-temperature resistance furnace, preheat to 250-350℃, and keep warm for 10-20h; S52 preheats and keeps the edge rolling roll sleeve warm, then quickly takes it out of the furnace and places it on the hot loading pit; S53 uses a crane to hoist the processed edge rolling roller shaft, and then installs it through the edge rolling roller sleeve for hot installation; After hot charging, S54 is subjected to slow cooling, and the slow cooling temperature is ≤50℃.

2. The method for manufacturing an edge rolling roller for rail beam rolling according to claim 1, characterized in that: In S11, the outer layer and the core of the roller sleeve are smelted in different medium frequency furnaces respectively, and different power supply times are controlled according to their respective smelting time and furnace-out time.

3. The method for manufacturing an edge rolling roller for rail beam rolling according to claim 1, characterized in that: In S3, the quenching temperature is controlled at 1080-1100°C, and the holding time is controlled at 8-12h; the tempering holding time is controlled at 30-50h, and the tempering times are controlled at 3 times.

4. The method for manufacturing an edge rolling roller for rail beam rolling according to claim 1, characterized in that: In S4, the finished product size is processed, wherein the inner hole is finely ground by a grinder, and the inner hole size is interference fit with the roller shaft of the edge rolling roller, and the interference amount is controlled at 1.0-1.2‰.

5. The method for manufacturing an edge rolling roller for rail beam rolling according to claim 1, characterized in that: In S52, after the edge rolling rollers are preheated and kept warm, they are taken out of the furnace within 8 minutes and placed on the hot charging pit. The hot charging pit is circular with a pit opening diameter of φ700mm and a pit depth of ≥2m. The entire pit is a reinforced concrete structure.

6. The method for manufacturing an edge rolling roller for rail beam rolling according to claim 1, characterized in that: In S53, the machined edge rolling roller shaft and the assembly part are machined by a grinder, and the machining process is matched with the edge rolling roller sleeve, and the interference is controlled at 1.0-1.2‰.

7. The method for manufacturing an edge rolling roller for rail beam rolling according to claim 1, characterized in that: In S54, after hot loading is completed, the aluminum silicate needle-punched blanket is used to wrap the edge rolling roller cover. After naturally cooling to 50°C, the aluminum silicate needle-punched blanket is removed and packed for storage.

8. The method for manufacturing an edge rolling roller for rail beam rolling according to claim 1, characterized in that: The prepared edge rolling roller has a roller body hardness of HSD80-90, a roller diameter hardness of 40-50HSD, and a journal strength of ≥800Mpa.