Manufacturing method of supporting roller made of semi-high-speed steel material

Abstract

The invention discloses a manufacturing method of a semi-high-speed steel supporting roller, which belongs to the field of roller manufacturing and comprises the following steps: preparing steel raw materials, so that the steel comprises the following chemical components in percentage by weight: 0.35-0.45% of C, 1.20-1.40% of Si, 0.40-0.60% of Mn, 7.00-9.00% of Cr, less than or equal to 1.00% of Ni, 2.00-3.00% of Mo, 0.50-0.80% of V and less than or equal to 0.010% of P; s is less than or equal to 0.010%; and the balance of Fe and inevitable impurities. Molten steel is prepared according to a steel smelting principle, and a steel ingot is prepared by pouring the molten steel according to a low-pouring-speed technology; a steel ingot is manufactured into a roller blank according to a forging procedure production process, the roller blank is sequentially subjected to heat treatment including preheating, high-temperature heating, precooling, rapid cooling and three times of tempering, the roller blank subjected to heat treatment is machined, the dimensional tolerance and the form and location tolerance of all parts are guaranteed, and finally the forged steel supporting roller made of the semi-high-speed steel material is obtained. According to the method, the large forged steel supporting roller with high wear resistance and high accident resistance can be produced, and production is effectively guaranteed.

Description

Technical Field

[0001] The invention relates to the field of support roller manufacturing, in particular to a method for manufacturing a support roller made of semi-high-speed steel. Background Art

[0002] With the rapid development of the steel industry, the material grades and performance of hot-rolled plates are constantly improving, and the proportion of high-grade or high-strength plates is increasing. In order to adapt to the changes in working conditions, the material of hot-rolled working rolls has been gradually upgraded from high-chromium iron or high-chromium steel to high-speed steel. However, because the current material of the paired support rolls cannot match the material of high-speed steel, the support roll surface may be more seriously damaged, and the probability of falling and peeling will increase significantly; the support rolls need to be replaced frequently, resulting in an increase in production costs. At the same time, market competition is becoming more and more fierce, and new high-performance support rolls are needed on the rolling line to significantly extend the service life of the rolls. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for manufacturing a semi-high-speed steel support roller, which can produce large-scale forged steel support rollers with high wear resistance and high accident resistance, and effectively ensure production.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for manufacturing a semi-high-speed steel support roller, comprising the following steps:

[0005] Step 1: Prepare steel raw materials so that the chemical composition and weight percentage of the steel are: C 0.35%-0.45%, Si 1.20%-1.40%, Mn 0.40%-0.60%, Cr 7.00%-9.00%, Ni≤1.00%, Mo2.00%-3.00%, V 0.50-0.80%, P≤0.010%; S≤0.010%; the rest are Fe and unavoidable impurities;

[0006] Step 2: Prepare molten steel by melting steel materials, and adopt low pouring speed technology to pour the molten steel to prepare steel ingots;

[0007] Step 3: The steel ingot is used to produce a roll blank according to the forging process;

[0008] Step 4: The roller is subjected to heat treatments of preheating, high temperature heating, precooling, rapid cooling and three temperings in sequence;

[0009] Step 5: The heat-treated roller blank is machined to ensure the dimensional tolerance and shape and position tolerance of each part, and finally a semi-high-speed steel forged steel support roller is obtained.

[0010] A further improvement of the technical solution of the present invention is that when pouring the ingot in step 2, a low pouring speed of 0.3 to 0.8 t / min is used to pour the molten steel.

[0011] The further improvement of the technical solution of the present invention is that: in step 3, a large reduction forging technology is adopted, the main deformation reduction is 20-30%, and a wide flat anvil is used for flattening forging during drawing.

[0012] The further improvement of the technical solution of the present invention is that the specific steps of step 4 are as follows:

[0013] Step 4.1: The roll blank is first placed in a box furnace and preheated to 400-450°C;

[0014] Step 4.2: The roller body enters the induction quenching equipment for induction heating, heated to the austenitizing temperature of 1040-1080°C, and austenite insulation is performed;

[0015] Step 4.3: After the heat preservation is completed, let it stand for 15-30 minutes to allow the roller temperature to slowly drop to 900-940℃;

[0016] Step 4.4: spray water for rapid cooling for 180-240 minutes, with a water spray pressure of 0.1-0.3 MPa;

[0017] Step 4.5: Perform a tempering treatment at 500-600℃, keep warm for 40-60h, and then slowly cool down to room temperature after taking out of the furnace;

[0018] Step 4.6: Perform secondary tempering treatment at 500-600℃, keep warm for 40-60h, and then slowly cool down to room temperature after being taken out of the furnace;

[0019] Step 4.7: Perform three tempering treatments at 500-600℃, keep warm for 40-60h, and then slowly cool down to room temperature after removing from the furnace.

[0020] A further improvement of the technical solution of the present invention is that the diameter of the manufactured support roller is 800-1400 mm and the length is 2000-4000 mm.

[0021] A further improvement of the technical solution of the present invention is that the working layer of the manufactured support roller is a tempered martensite structure with a surface hardness of ≥60HSD.

[0022] Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is: by greatly increasing the content of main alloying elements such as Cr, Mo, and V in the raw material ratio, the material has the basic properties of semi-high-speed steel, and the wear resistance and accident resistance of the support roller are improved. By adopting low casting speed technology to produce steel ingots, the component segregation caused by alloy components is avoided, and the tendency of solidification looseness is reduced. By adopting large reduction forging technology, the main deformation reduction is 20-30%, and the wide flat anvil is used for flattening forging during drawing, the width of the metal plastic flow range near the axis of the steel ingot is increased, and the problem of forging impermeability or forging cracking inside the high-quality rolling mill roll is solved. The heat treatment of the roller blank adopts preheating + high-temperature heating + precooling + rapid cooling + three tempering, so that the working layer of the support roller obtains a full martensitic structure, reduces quenching stress, and avoids quenching cracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with embodiments:

[0026] like Figure 1 FIG. 1 is a flow chart of a method for manufacturing a semi-high-speed steel support roller, which specifically includes the following steps:

[0027] Step 1: Prepare steel raw materials so that the chemical composition and weight percentage of the steel are: C 0.35%-0.45%, Si 1.20%-1.40%, Mn 0.40%-0.60%, Cr 7.00%-9.00%, Ni≤1.00%, Mo2.00%-3.00%, V 0.50-0.80%, P≤0.010%; S≤0.010%; the rest are Fe and unavoidable impurities;

[0028] Step 2: Molten steel is obtained by the principle of smelting steel, and the low pouring speed technology is adopted to pour the molten steel to obtain steel ingots; the low pouring speed technology is adopted to produce steel ingots, and the pouring speed is implemented according to 0.3-0.8t / min, which avoids the component segregation caused by the alloy components and reduces the tendency of solidification looseness.

[0029] Step 3: The steel ingot is made into a roller blank according to the forging process production process; the large reduction forging technology is adopted, the main deformation reduction is 20-30%, and the wide flat anvil is used for flattening forging during drawing to increase the width of the metal plastic flow range near the axis of the steel ingot, so as to solve the problem of internal forging or forging cracking of high-quality rolling mill rolls.

[0030] Step 4: The roller is subjected to heat treatments of preheating, high temperature heating, precooling, rapid cooling and three temperings in sequence;

[0031] Step 4.1: The roll blank is first placed in a box furnace and preheated to 400-450°C;

[0032] Step 4.2: The roller body enters the induction quenching equipment for induction heating, heated to the austenitizing temperature of 1040-1080°C, and austenite insulation is performed;

[0033] Step 4.3: After the heat preservation is completed, let it stand for 15-30 minutes to allow the roller temperature to slowly drop to 900-940℃;

[0034] Step 4.4: spray water for rapid cooling for 180-240 minutes, with a water spray pressure of 0.1-0.3 MPa;

[0035] Step 4.5: Perform a tempering treatment at 500-600℃, keep warm for 40-60h, and then slowly cool down to room temperature after taking out of the furnace;

[0036] Step 4.6: Perform secondary tempering treatment at 500-600℃, keep warm for 40-60h, and then slowly cool down to room temperature after being taken out of the furnace;

[0037] Step 4.7: Perform three tempering treatments at 500-600℃, keep warm for 40-60h, and slowly cool down to room temperature. The working layer structure with a martensite matrix is ​​obtained, and the surface hardness is ≥60HSD.

[0038] Step 5: The heat-treated roller blank is machined to ensure the dimensional tolerance and shape and position tolerance of each part, and finally a semi-high-speed steel forged steel support roller is obtained. The diameter of the manufactured support roller is 800-1400mm and the length is 2000-4000mm.

[0039] According to the above steps, support rollers are produced respectively, wherein only the chemical composition and weight percentage of the alloy raw materials and relevant parameters in the processing process are changed, and the support rollers in Examples 1 to 4 and the support rollers in the comparative example are obtained respectively.

[0040] Table 1 Comparison table of main chemical components and weight percentage of support rollers of Examples 1 to 4 and comparative examples

[0041]

[0042] Table 2 Comparison table of casting and forging parameters of support rollers of Examples 1 to 4 and comparative examples

[0043]

[0044] The comparative example adopts conventional smelting and forging processes.

[0045] Table 3 Comparison of heat treatment process parameters of support rollers of Examples 1 to 4 and comparative examples

[0046]

[0047] Table 4 Wear resistance test results

[0048] Example Hardness HRC Relative wear resistance 1 48.0 4.5 2 50.0 4.8 3 52.0 5.2 4 53.0 5.5 Comparative Example 50.0 2.4

[0049] According to the parameters shown in Tables 1 to 3, support rollers of Examples 1 to 4 were manufactured according to the manufacturing method of the semi-high-speed steel support roller, and samples of the support rollers of Examples 1 to 4 were taken for laboratory wear and hardness testing. Compared with the conventional support rollers of the comparative example, the wear resistance is obvious.

[0050] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for manufacturing a semi-high-speed steel support roller, characterized in that: The steps include: Step 1: Prepare steel raw materials so that the chemical composition and weight percentage of the steel are: C 0.35%-0.45%, Si 1.20%-1.40%, Mn 0.40%-0.60%, Cr 7.00%-9.00%, Ni≤1.00%, Mo2.00%-3.00%, V 0.50-0.80%, P≤0.010%; S≤0.010%; the rest are Fe and unavoidable impurities; Step 2: Prepare molten steel by melting steel materials, and adopt low pouring speed technology to pour the molten steel to prepare steel ingots; Step 3: The steel ingot is used to produce a roll blank according to the forging process; Step 4: The roller is subjected to heat treatments of preheating, high temperature heating, precooling, rapid cooling and three temperings in sequence; Step 5: The heat-treated roller blank is machined to ensure the dimensional tolerance and shape and position tolerance of each part, and finally a semi-high-speed steel forged steel support roller is obtained.

2. The method for manufacturing a semi-high-speed steel support roller according to claim 1, characterized in that: When pouring the ingot in step 2, a low pouring speed of 0.3 to 0.8 t / min is used to pour the molten steel.

3. The method for manufacturing a semi-high-speed steel support roller according to claim 1, characterized in that: In step 3, a large reduction forging technology is used, with a main deformation reduction of 20-30%, and a wide flat anvil is used for flattening forging during drawing.

4. The method for manufacturing a semi-high-speed steel support roller according to claim 1, characterized in that: Step 4 The specific steps are as follows: Step 4.1: The roll blank is first placed in a box furnace and preheated to 400-450°C; Step 4.2: The roller body enters the induction quenching equipment for induction heating, heated to the austenitizing temperature of 1040-1080°C, and austenite insulation is performed; Step 4.3: After the heat preservation is completed, let it stand for 15-30 minutes to allow the roller temperature to slowly drop to 900-940℃; Step 4.4: spray water for rapid cooling for 180-240 minutes, with a water spray pressure of 0.1-0.3 MPa; Step 4.5: Perform a tempering treatment at 500-600℃, keep warm for 40-60h, and then slowly cool down to room temperature after taking out of the furnace; Step 4.6: Perform secondary tempering treatment at 500-600℃, keep warm for 40-60h, and then slowly cool down to room temperature after being taken out of the furnace; Step 4.7: Perform three tempering treatments at 500-600℃, keep warm for 40-60h, and then slowly cool down to room temperature after removing from the furnace.

5. The method for manufacturing a semi-high-speed steel support roller according to claim 1, characterized in that: The manufactured support roller has a diameter of 800 to 1400 mm and a length of 2000 to 4000 mm.

6. The method for manufacturing a semi-high-speed steel support roller according to claim 1, characterized in that: The working layer of the manufactured support roller is a tempered martensite structure, and the surface hardness is ≥60HSD.

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