A forging tool and a forging method for a continuous rolling mill backup roll

Abstract

The present application relates to a kind of continuous rolling mill backup roll's forging tool and forging method, belong to backup roll forging technical field, solve the technical problems of the heart of the forging piece flaw detection unqualified, more forging piece surface crack and low forging production efficiency in prior art.The forging tool includes full coverage wide flat anvil auxiliary tool;Full coverage wide flat anvil auxiliary tool includes upper flat anvil and lower flat anvil;The structure and size of upper flat anvil and lower flat anvil are same and completely cover blank between upper flat anvil and lower flat anvil.The forging method includes: step 1, using full coverage wide flat anvil auxiliary tool to carry out multiple pass square bar drawing, chamfering and roundness;Step 2, after roundness, blank both ends are cut off, and the roll neck of the length of the nozzle section and the riser end is drawn, finally finishing product, obtains continuous rolling mill backup roll.The present application improves the surface quality of backup roll, and greatly saves production cost, improves production efficiency.

Description

Technical Field

[0001] This invention relates to the field of support roll forging technology, and in particular to a forging fixture and forging method for a support roll of a continuous rolling mill. Background Technology

[0002] Support rolls are important components of rolling mills, used to support work rolls or intermediate rolls to prevent work rolls from flexing and deforming, which would affect the output and quality of plates and strips. Therefore, the quality characteristics of support rolls are particularly important.

[0003] Drawing is an essential process in the forging of large shaft forgings and a major process that affects the quality of forgings. The drawing process reduces the cross-sectional area of ​​the billet and increases its length. It also breaks up coarse grains, forges together internal porosity and voids, and refines the as-cast structure, thereby obtaining a homogeneous and dense high-quality forging.

[0004] The traditional continuous rolling mill support roll forging method is as follows: the first forging is to press the jaws, chamfer, and remove the bottom of the ingot; the second forging is to upset and draw out using a KD drawing method, or to draw out using a flat anvil and a V-shaped anvil; and the third forging is to draw out the finished product.

[0005] Due to the high alloy content of the roll material, the main problems in the forging process are: unqualified core inspection of the forgings, numerous surface cracks, especially during the upsetting process, where transverse and longitudinal cracks are very likely to appear on the surface of the ingot. Cracks are also prone to appear at the hammer-to-hammer overlap during the KD process, which limits the KD reduction. The cleaning process severely restricts the production efficiency of roll forging, and in severe cases, there is a risk of scrapping. At the same time, because of the severity of cracks, it is necessary to increase the forging allowance, resulting in a generally low utilization rate of forgings and a reduction in product profit margin. Summary of the Invention

[0006] Based on the above analysis, the present invention aims to provide a forging fixture and forging method for a continuous rolling mill support roll, in order to solve the problems of unqualified core flaw detection, numerous surface cracks, and low production efficiency of forgings produced by the existing continuous rolling mill support roll forging method.

[0007] The objective of this invention is mainly achieved through the following technical solutions:

[0008] On the one hand, the present invention provides a forging fixture for a continuous rolling mill support roll, including a full-coverage wide flat anvil fixture;

[0009] The full-coverage wide flat anvil fixture includes an upper flat anvil and a lower flat anvil; the upper flat anvil and the lower flat anvil have the same structure and size and completely cover the billet placed between the upper flat anvil and the lower flat anvil.

[0010] In one possible design, the lengths of both the upper and lower flat anvils are 3800-4000 mm;

[0011] The width of both the upper and lower flat anvils is 2300-2500mm.

[0012] On the other hand, the present invention also provides a forging method for a continuous rolling mill support roll, using the forging tooling for the continuous rolling mill support roll described above;

[0013] The forging method includes the following steps:

[0014] Step 1: Use a full-coverage wide flat anvil tool to perform multiple rounding operations. After multiple rounding operations, perform 1-2 rounding operations, and then perform multiple rounding operations.

[0015] Step 2: After rounding, cut the billet at both ends, lengthen the roll neck of the sprue section and riser end, and finally finish the finished product to obtain the continuous rolling mill support roll.

[0016] Furthermore, in step 1, the first firing involves placing the billet in the furnace for heat preservation before forging;

[0017] The insulation temperature is 1250±10℃, and the insulation time is ≥30h.

[0018] Furthermore, in step 1, after heat preservation, the billet is taken out of the furnace for forging. The initial forging temperature is 1220±10℃ and the final forging temperature is 850±10℃.

[0019] The billet forging process includes: using a full-coverage wide flat anvil to perform multiple square drawing processes on the billet, forming a square billet, and then performing chamfering and rounding processes on the square billet.

[0020] Furthermore, in step 2, during the second firing, the billet that has been squared, chamfered, and rounded is placed in the furnace for heat preservation at a temperature of 1250±10℃ for a time of ≥10h, and then removed from the furnace for forging.

[0021] Furthermore, in step 2, the initial forging temperature after heat preservation and forging is 1220±10℃, and the final forging temperature is ≥800℃.

[0022] During the forging process, the material is fed from the sprue end using an upper flat anvil and a lower V-anvil, and the roll neck at the sprue end is lengthened to the size of the forging. Then, the material is fed from the riser end, and the roll neck at the riser end is lengthened to the size of the forging. Finally, the finished product is obtained, which is the support roll of the continuous rolling mill.

[0023] Furthermore, in step 1, during the multi-pass square drawing process, the reduction amount of a single pass square drawing is 30-35% of the billet height before reduction.

[0024] Furthermore, in step 1, the multi-pass extraction process includes:

[0025] In the first round of square drawing, the height of the billet after pressing is 1300mm ± 10mm;

[0026] In the second round of square drawing, the billet is rotated 90° around the billet axis, and the height of the billet after pressing is 1530mm±10mm.

[0027] The third round of square drawing process involves rotating the billet 90° around its axis, resulting in a billet height of 1350mm ± 10mm after pressing down.

[0028] The fourth step of square drawing involves rotating the billet 90° around its axis, resulting in a height of 1350mm ± 10mm after pressing down.

[0029] In the fifth round of square drawing, the billet is rotated 90° around its axis, and the height of the billet after pressing is 1400mm ± 10mm.

[0030] Furthermore, in step 1, after the multi-pass squaring process, the billet undergoes two passes of chamfering to create an octagon, followed by multiple passes of rounding, including the following processes:

[0031] In the sixth pass (first octagonal treatment), the billet is rotated 45° around the billet axis, and the height of the billet after pressing is 1370mm±10mm.

[0032] In the seventh pass (first octagonal treatment), the billet is rotated 90° around the billet axis, and the height of the billet after pressing is 1450mm; then multiple passes are performed to round it to the support roller Φ1510mm.

[0033] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0034] (1) When using existing forging fixtures, some of the billet is exposed outside the upper and lower anvils, requiring multiple hammer overlaps. During each overlap, the tensile stress of the billet increases, making it prone to cracks and resulting in poor quality of the semi-steel material. This invention provides a forging fixture for a continuous rolling mill support roll. The forging fixture includes a fully covered wide flat anvil auxiliary tool, which includes an upper flat anvil and a lower flat anvil. The billet is placed between the upper and lower flat anvils and is completely covered. During forging, zero overlap can be achieved with each hammer, thereby significantly increasing the deformation of the semi-steel roll. At the same time, the tensile stress of the billet between the upper and lower flat anvils is reduced, thereby reducing the generation of surface cracks and ultimately achieving the purpose of improving the forging compaction effect of the continuous rolling mill support roll.

[0035] (2) By adopting a full-coverage wide flat anvil, the present invention avoids the surface cracking phenomenon at the hammer-to-hammer overlap in the prior art, thereby improving the surface quality of the billet and reducing the amount of oxygen blown into the billet.

[0036] (3) The traditional continuous rolling mill support roll forging method involves the first pass for pressing the jaws, chamfering, and removing the ingot bottom; the second pass for upsetting, KD drawing, or upper flat and lower V anvil drawing; and the third pass for drawing the finished product. Upsetting increases the billet diameter and drawing ratio, while simultaneously breaking up the as-cast structure. However, upsetting is completed on the upsetting stencil, requiring jaw pressing for easy clamping. This invention eliminates upsetting and jaw pressing. Even if clamping is required, the riser diameter obtained by this invention can meet the clamping requirements of the manipulator. Therefore, this invention eliminates the jaw pressing and upsetting processes, greatly reducing production time, saving production costs, and improving production efficiency.

[0037] (4) Existing forging methods use the KD drawing method, which means that during the production process, the dimension (i.e., reduction amount) after each pressing is greater than the target dimension. The forging method provided by this invention includes an ultimate forging compaction process: that is, the reduction amount is determined according to 30-35% of the billet height, thereby calculating the dimension after pressing. The dimension after pressing is less than the target dimension, and the minimum dimension after pressing is calculated as 0.9 times the target dimension. The ultimate forging compaction process can enable the billet to achieve ultimate deformation, greatly increase the billet reduction amount, better compact the defects in the core of the support roller, and ultimately improve the flaw detection pass rate of the support roller.

[0038] (5) The production efficiency is greatly improved by forging according to the method provided by the present invention. The original process of pressing the jaws + upsetting + KD drawing takes about 120 minutes. The method of the present invention eliminates the pressing jaws and upsetting process and directly uses a full-coverage wide flat anvil auxiliary tool to draw to the blank size, shortening the forging time to 50 minutes. At the same time, the surface and core quality of the support roller are significantly improved. The support roller products produced by this method are all qualified in the flaw detection.

[0039] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0040] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0041] Figure 1 A schematic diagram of the forging fixture for the support rolls of a continuous rolling mill;

[0042] Figure 2 This is a schematic diagram of the structure of the support rolls of a continuous rolling mill;

[0043] Figure 3To simulate the equivalent deformation cloud diagram of the core of the support roll of a continuous rolling mill using the finite element method;

[0044] Figure 4 This is a schematic diagram of the support rolls of the continuous rolling mill at the test site;

[0045] Figure 5 This is a schematic diagram of the support rolls of a continuous rolling mill during the forging process;

[0046] Figure 6 The ultrasonic flaw detection results are for the continuous rolling mill support rolls produced in Example 1;

[0047] Figure 7 The ultrasonic flaw detection results are for the support rolls of the continuous rolling mill produced in Example 2.

[0048] Figure label:

[0049] 1-Blank; 2-Upper flat anvil; 3-Lower flat anvil. Detailed Implementation

[0050] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0051] On the one hand, the present invention provides a forging fixture for a continuous rolling mill support roll, such as Figure 1 As shown, the forging fixture for the continuous rolling mill support roll includes a fully covered wide flat anvil; the fully covered wide flat anvil includes an upper flat anvil 2 and a lower flat anvil 3; the upper flat anvil 2 and the lower flat anvil 3 have the same size; when forging the continuous rolling mill support roll using the fully covered wide flat anvil, the billet 1 is placed between the upper flat anvil 2 and the lower flat anvil 3, and is completely covered by the upper flat anvil 2 and the lower flat anvil 3.

[0052] When using existing forging fixtures for forging, part of the billet 1 is exposed outside the upper and lower anvils, thus failing to completely cover the billet 1. Therefore, multiple hammers are required for overlapping. During each overlapping process, the tensile stress of the billet 1 increases, making it prone to cracks and resulting in poor quality of the semi-steel material.

[0053] Compared with the prior art, the forging fixture for the continuous rolling mill support roll provided by the present invention includes a fully covered wide flat anvil auxiliary tool, which includes an upper flat anvil 2 and a lower flat anvil 3. The billet 1 is placed between the upper flat anvil 2 and the lower flat anvil 3 and is completely covered. During forging, zero overlap can be achieved for each hammer blow, thereby significantly increasing the deformation of the semi-steel roll. At the same time, the tensile stress of the billet 1 between the upper flat anvil and the lower flat anvil is reduced, thereby reducing the generation of surface cracks and ultimately achieving the purpose of improving the forging compaction effect of the continuous rolling mill support roll.

[0054] To ensure the achievement of the ultimate forging and compaction process, the lengths of the upper anvil 2 and the lower anvil 3 of this invention are both 3800-4000 mm; the widths of the upper anvil 2 and the lower anvil 3 are both 2300-2500 mm.

[0055] Compared with existing forging fixtures, the full-coverage wide flat anvil provided by this invention is an ultra-wide and ultra-long anvil, which can achieve the effect of fully covering the billet 1. In addition, the use of the full-coverage wide flat anvil for forging can also reduce the oxygen blowing time. This is because the support roller material has a high carbon content and alloy content, and the surface is prone to cracking during the forging process. When the full-coverage wide flat anvil is used, the surface of the billet 1 is completely covered by the upper flat anvil 2 and the lower flat anvil 3, and the surface of the billet 1 between the upper flat anvil and the lower flat anvil is under compressive stress.

[0056] It should be noted that the extreme forging provided by this invention refers to the forging reduction dimension reaching a minimum value, specifically manifested in the height after reduction during the forging process being less than the final target dimension. The advantage of using extreme forging is that it can significantly increase the deformation amount. Existing forging methods ensure that the target height of each pass during forging is not less than the final target dimension; for example, if the target dimension is 1500mm, then the height after reduction in each pass is not less than 1500mm. However, the full-coverage wide flat anvil fixture used in this invention is characterized by a large lateral width (the lengths of the upper flat anvil 2 and lower flat anvil 3 are both 3800-4000mm; the widths of the upper flat anvil 2 and lower flat anvil 3 are both 2300-2500mm). Therefore, the height after reduction in intermediate passes can be reduced to a minimum dimension, while still ensuring that the target dimension is achieved. For example, in the embodiment, the target dimension is Φ1510mm, and the height after reduction in intermediate passes can be reduced to 1350mm. This is the extreme deformation process; extreme deformation brings a large deformation amount, and this large deformation amount can achieve compaction of core defects.

[0057] On the other hand, the present invention also provides a method for non-upsetting limit forging compaction of support rolls in continuous rolling mills, using the forging tooling described above. This forging compaction method specifically includes the following steps:

[0058] Step 1, First forging: Before forging billet 1, billet 1 is placed in the furnace for heat preservation at a temperature of 1250±10℃ for ≥30 hours. After heat preservation, billet 1 is removed from the furnace for forging. The initial forging temperature is 1220±10℃, and the final forging temperature is ≥850℃. The forging process of billet 1 includes: using a full-coverage wide flat anvil to perform multiple rounding processes on billet 1, rounding it to □1400 (meaning that a square billet of 1400mm×1400mm is formed after rounding), and then the square billet is subjected to chamfering and rounding.

[0059] Step 2: After rounding, cut the billet from both ends, lengthen the roll necks at the sprue and riser ends, and finally finish the product to obtain the continuous rolling mill support rolls, such as... Figure 2 As shown.

[0060] The existing support roller forging method consists of pressing the jaws, upsetting, KD (knockout), drawing, and blanking to produce the finished product, which is divided into the above 5 processes. Among them, upsetting and KD compaction are the main compaction processes.

[0061] Compared with the prior art, the present invention has improved the compaction stage. The present invention eliminates the pressing jaw, upsetting and drawing processes, and uses a full-coverage wide flat anvil auxiliary tool for forging compaction. The whole process is reduced to the process of compaction by full-coverage wide flat anvil and blanking to produce finished product. The present invention can achieve the effect of the existing pressing jaw + upsetting + KD compaction.

[0062] Furthermore, it should be emphasized that, compared with the prior art, the forging production according to the forging method of the present invention significantly improves production efficiency. The original process of pressing the jaws + upsetting + KD + drawing takes about 120 minutes in total. The compaction method of the present invention eliminates the pressing jaws and upsetting process, and directly draws the wide flat anvil to the blanking size, shortening the forging time to 50 minutes. At the same time, the surface and core quality are significantly improved, and the support roller products produced by this method all pass the flaw detection.

[0063] In step 1 above, during the multi-pass square drawing process, the reduction amount in a single pass is 30-35% of the height of the billet 1 before pressing.

[0064] The specific operating procedures are as follows:

[0065] In the first rounding process, the height of billet 1 before pressing is 2009mm, and the height after pressing is 1300mm.

[0066] In the second round of square drawing, billet 1 is rotated 90° around its axis. Before pressing, the height of billet 1 is 2360mm, and after pressing, the height is 1530mm.

[0067] In the third round of square drawing, billet 1 is rotated 90° around its axis. Before pressing, the height of billet 1 is 1700mm, and after pressing, the height is 1350mm.

[0068] In the fourth round of square drawing, billet 1 is rotated 90° around its axis. Before pressing, the diameter of billet 1 is 1820mm, and after pressing, the height is 1350mm.

[0069] In the fifth round of square drawing, billet 1 is rotated 90° around its axis. Before pressing, the diameter of billet 1 is 1720mm, and after pressing, the height is 1400mm.

[0070] In the sixth pass (the first pass is the chamfering of the octagon), the billet 1 is rotated 45° around its axis. Before pressing, the diameter of the billet 1 is 1980mm, and after pressing, the height is 1370mm. It should be noted that the first 5 passes are for square drawing, and the chamfering and rounding begin in the 6th pass. Therefore, the 6th pass is rotated 45°.

[0071] In the seventh pass (the second pass with the inverted octagon), the billet 1 is rotated 90° around its axis. Before pressing, the diameter of the billet 1 is 2220mm, and after pressing, the height is 1450mm. Then, multiple passes are used to round it to Φ1510.

[0072] In step 1 above, seven compaction passes are designed, of which five passes are for square compaction, and the sixth and seventh passes are for inverted octagonal compaction. The number of passes and the amount of compaction per pass mainly depend on the size of the steel ingot and the size of the forging (see [link to details] for steel ingot and forging dimensions). Figure 3 The steel ingot is made of Cr5 material, and its dimensions are: riser diameter of 2009mm, nozzle diameter of 1776mm, and ingot length of 2838mm. It also meets the requirement of a pass reduction rate of 30-35%.

[0073] In step 1, since the final forging is a circular shaft, chamfering and rounding is a necessary step to chamfer and round the square blank 1 into a circular blank 1.

[0074] In step 2 above, during the second heat treatment, the billet 1, after being squared, chamfered, and rounded, is placed in the furnace for heat treatment at a temperature of 1250±10℃ for ≥10 hours. After heat treatment, it is removed from the furnace for forging. The initial forging temperature is 1220±10℃, and the final forging temperature is ≥800℃. The forging process uses an upper flat anvil and a lower V-anvil for blanking, then blanking from the sprue end, lengthening the roll neck at the sprue end to the forging size, then blanking from the riser end, lengthening the roll neck at the riser end to the forging size, and finishing to obtain the continuous rolling mill support roll.

[0075] In step 2 above, the initial forging temperature and the final forging temperature are kept within the aforementioned range because: the initial forging temperature is the highest allowable heating temperature for the material, and it should not be too high, otherwise overheating and burning may occur. However, the initial forging temperature should not be too low either, otherwise the forging operation time will be shortened, the forging temperature range will be shortened, and the forging difficulty will be increased. The final forging temperature is the temperature at which forging is stopped. If the final forging temperature is too low, recrystallization cannot occur, cold deformation strengthening cannot be eliminated, deformation resistance is high, and the forging is prone to cracking. If the final forging temperature is too high, the billet grains will become coarse, and the performance of the forging will decrease.

[0076] It should be noted that the dimensions of the forgings are controlled by the computer program of the hydraulic press, and the pressing endpoint is given for each operation stage to control the dimensions of the billet 1.

[0077] Compared with traditional forging methods, the surface and core quality of the continuous rolling mill support rolls obtained by this invention are significantly improved as well as production efficiency, thereby greatly improving forging efficiency and product flaw detection pass rate. The reference standard for qualified forging products is JB / T4120-2006 "Large Forged Alloy Steel Support Rolls".

[0078] It should be noted that this invention uses a full-coverage wide flat anvil for forging to break up the as-cast structure, simultaneously compacting the core casting defects, and achieving the final desired forging shape. The quality of forging compaction is mainly reflected in the compaction of core defects, and the core compaction effect can only be determined by subsequent flaw detection. The product flaw detection pass rate is the only metric, and the flaw detection inspection of the continuous rolling mill support rolls produced by this invention has all passed.

[0079] In addition, this invention performed a finite element simulation of the core of the support roller produced using a full-coverage wide flat anvil fixture. The simulation results of the full-coverage wide flat anvil fixture process are shown in [the table below]. Figure 3 The equivalent core strain value of forgings produced by the present invention using a full-coverage wide flat anvil can reach 3, which is also around 3 in the traditional KD forging method. The two are comparable in effect. However, compared with the prior art, the present invention avoids the surface cracking phenomenon at the hammer-to-hammer overlap in the prior art by using a full-coverage wide flat anvil, thereby improving the surface quality of the billet and reducing the amount of oxygen blown into the billet. At the same time, the present invention eliminates the pressing and upsetting processes, which greatly reduces production time, saves production costs, and improves production efficiency.

[0080] Example 1

[0081] In this embodiment, the continuous rolling mill support roll is prepared using the forging tooling and forging method described above. The length of the upper flat anvil 2 and the lower flat anvil 3 is 4000 mm, and the width of the upper flat anvil 2 and the lower flat anvil 3 is 2400 mm.

[0082] The specific implementation process of this embodiment is as follows:

[0083] Step 1, First forging: The ingot is put into the furnace at a temperature of 1241-1257℃ and held for 32 hours. Then it is taken out of the furnace for forging at an initial forging temperature of 1215-1227℃ and a final forging temperature of 867℃. After the steel ingot is taken out of the furnace, it is squared to □1400 (referring to a square billet of 1400mm×1400mm) using a full-coverage wide flat anvil and then chamfered and rounded to Φ1510.

[0084] The specific operating procedures are as follows:

[0085] In the first pass, the height of billet 1 before pressing is 2009mm, and the height after pressing is 1300mm;

[0086] In the second pass, billet 1 is rotated 90° around its axis. Before pressing, the height of billet 1 is 2360mm, and after pressing, the height is 1530mm.

[0087] In the third pass, the billet 1 is rotated 90° around its axis. Before pressing, the height of the billet 1 is 1700mm, and after pressing, the height is 1350mm.

[0088] In the fourth pass, billet 1 is rotated 90° around its axis. Before pressing, the diameter of billet 1 is 1820mm, and after pressing, the height is 1350mm.

[0089] In the fifth pass, billet 1 is rotated 90° around its axis. Before pressing, the diameter of billet 1 is 1720mm, and after pressing, the height is 1400mm.

[0090] In the sixth pass (the first pass with an inverted octagon), the billet 1 is rotated 45° around its axis. Before pressing, the diameter of the billet 1 is 1980mm, and after pressing, the height is 1370mm.

[0091] In the seventh pass (the second pass with the inverted octagon), the billet 1 is rotated 90° around its axis. Before pressing, the diameter of the billet 1 is 2220mm, and after pressing, the height is 1450mm. Then, multiple passes are used to round it to Φ1510.

[0092] Step 2: Second forging, furnace temperature 1253-1258℃, hold for 10 hours, then forge from the furnace, initial forging temperature 1223-1228℃, final forging temperature 855℃. Use an 850mm upper flat anvil and lower V anvil to unload from the sprue end, lengthen the sprue end roll neck to the forging size, then unload from the riser end, lengthen the riser end roll neck to the forging size, finish to obtain the finished product, and obtain the continuous rolling mill support roll.

[0093] This embodiment prepares the continuous rolling mill support roll as follows: Figure 4 As shown, the steel ingot is made of Cr5 steel, and its dimensions are: riser end diameter 2009mm, sprue end diameter 1776mm, and ingot body length (including the continuous rolling mill support roll) 2838mm. Its manufacturing process is as follows: Figure 5 As shown, the ultrasonic flaw detection results of the continuous rolling mill support rolls are as follows: Figure 6 As shown, the flaw detection is qualified.

[0094] Example 2

[0095] In this embodiment, the continuous rolling mill support roll is prepared using the forging tooling and forging method described above. The length of the upper anvil 2 and the lower anvil 3 used in this embodiment is 4000 mm, and the width of the upper anvil 2 and the lower anvil 3 is 2400 mm.

[0096] The specific implementation process of this embodiment is as follows:

[0097] For the first firing, the ingot is fed into the furnace at a temperature of 1250-1254℃ and held for 30 hours. Then it is taken out of the furnace for forging at an initial forging temperature of 1220-1225℃ and a final forging temperature of 858℃. After the ingot is taken out of the furnace, it is squared to □1400 (referring to a square billet of 1400mm×1400mm) using a fully covered wide flat anvil and then chamfered and rounded to Φ1510.

[0098] The specific operating procedures are as follows:

[0099] In the first rounding process, the height of billet 1 before pressing is 2009mm, and the height after pressing is 1300mm.

[0100] In the second round of square drawing, billet 1 is rotated 90° around its axis. Before pressing, the height of billet 1 is 2360mm, and after pressing, the height is 1530mm.

[0101] In the third round of square drawing, billet 1 is rotated 90° around its axis. Before pressing, the height of billet 1 is 1700mm, and after pressing, the height is 1350mm.

[0102] In the fourth round of square drawing, billet 1 is rotated 90° around its axis. Before pressing, the diameter of billet 1 is 1820mm, and after pressing, the height is 1350mm.

[0103] In the fifth round of square drawing, billet 1 is rotated 90° around its axis. Before pressing, the diameter of billet 1 is 1720mm, and after pressing, the height is 1400mm.

[0104] In the sixth pass (the first pass with an inverted octagon), the billet 1 is rotated 45° around its axis. Before pressing, the diameter of the billet 1 is 1980mm, and after pressing, the height is 1370mm.

[0105] In the seventh pass (the second pass with the inverted octagon), the billet 1 is rotated 90° around its axis. Before pressing, the diameter of the billet 1 is 2220mm, and after pressing, the height is 1450mm. Then, multiple passes are used to round it to Φ1510.

[0106] Step 2: Second forging, furnace temperature 1251-1257℃, hold for 10 hours, then forge from the furnace, initial forging temperature 1225-1228℃, final forging temperature 808℃. Use an 850mm upper flat anvil and lower V anvil to cut the material from the sprue end, lengthen the sprue end roll neck to the forging size, then cut the material from the riser end, lengthen the riser end roll neck to the forging size, finish to obtain the finished product, and obtain the continuous rolling mill support roll.

[0107] The ultrasonic flaw detection results of the continuous rolling mill support rolls prepared in this embodiment are as follows: Figure 7 As shown, the flaw detection is qualified. The steel ingot is made of Cr5 steel, and the ingot dimensions are: riser end diameter of 2009mm, sprue end diameter of 1776mm, and ingot body length (continuous rolling mill support roll) of 2838mm.

[0108] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A forging method for a support roll of a continuous rolling mill, characterized in that, The forging method includes the following steps: Step 1: Place the ingot into the furnace for heat preservation, then use a full-coverage wide flat anvil auxiliary tool to perform multiple rounding operations. After multiple rounding operations, perform 1-2 rounding operations, and then perform multiple rounding operations. The full-coverage wide flat anvil auxiliary tool includes an upper flat anvil and a lower flat anvil; the upper flat anvil and the lower flat anvil have the same structure and size and completely cover the billet placed between the upper flat anvil and the lower flat anvil, so that zero overlap can be achieved for each hammer blow during forging; The lengths of both the upper and lower flat anvils are 3800-4000 mm; The width of both the upper and lower flat anvils is 2300-2500 mm; The full-coverage wide flat anvil fixture can achieve extreme forging. During the extreme forging process, the height after pressing is less than the final target size, and the minimum size after pressing is calculated as 0.9 times the target size. When using a full-coverage wide flat anvil, the surface of the billet is completely covered by the upper and lower flat anvils, and the surface of the billet between the upper and lower flat anvils is under compressive stress. In step 1, the first firing involves placing the billet in the furnace for heat preservation before forging. The insulation temperature is 1250±10℃, and the insulation time is ≥30h; In step 1, after heat preservation, the billet is taken out of the furnace for forging. The initial forging temperature is 1220±10°C and the final forging temperature is 850±10°C. In the multi-pass forging process, the reduction amount in a single pass is 30-35% of the billet height before pressing. That is, the reduction amount is determined according to 30-35% of the billet height, thereby calculating the size after pressing. The size after pressing is smaller than the target size, and the minimum size after pressing is calculated as 0.9 times the target size. The forging method includes a limit forging compaction process. The steel ingot is made of Cr5 steel. The multi-stage extraction process includes: The height of the billet after the first rounding process is 1300mm ± 10mm. In the second round of square drawing, the billet is rotated 90° around the billet axis, and the height of the billet after pressing is 1530mm±10mm. The third round of square drawing process involves rotating the billet 90° around its axis, resulting in a billet height of 1350mm ± 10mm after pressing down. The fourth step of square drawing involves rotating the billet 90° around its axis, resulting in a height of 1350mm ± 10mm after pressing down. In the fifth round of square drawing, the billet is rotated 90° around the billet axis, and the height of the billet after pressing is 1400mm±10mm. After five passes of compaction, a sixth and seventh pass of inverted octagonal treatment is performed. The sixth step involves turning the billet 45° around its axis, resulting in a billet height of 1370mm ± 10mm after pressing down. The seventh step involves turning the billet 90° around its axis, resulting in a height of 1450mm after pressing down. Then, multiple rounding processes are performed until the support roller Φ1510mm is reached. Step 2: After rounding, cut the billet from both ends. The holding temperature is 1250±10℃, and the holding time is ≥10h. The initial forging temperature after holding is 1220±10°C, and the final forging temperature is ≥850°C. Cut the billet from the sprue end using an upper flat anvil and a lower V anvil, and lengthen the roll neck at the sprue end to the size of the forging. Then cut the billet from the riser end, lengthen the roll neck at the riser end to the size of the forging, and finally finish the finished product to obtain the continuous rolling mill support roll. The forging time is shortened to 50 minutes, and the equivalent strain value of the core of the forging can reach 3; the forging method eliminates upsetting and does not require clamping jaws.

2. The forging method for the support roll of a continuous rolling mill according to claim 1, characterized in that, In step 1, the first firing involves placing the billet in the furnace for heat preservation before forging; the heat preservation time is 30 hours.

3. The forging method for the support roll of a continuous rolling mill according to claim 1, characterized in that, In step 2, the billet that has been squared, chamfered and rounded is placed in the furnace for heat preservation for 10 hours.

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