A method for improving hot rolling edge cracking of titanium bronze strip
Patent Information
- Application Number
- CN202610767158.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-29
- Publication Date
- 2026-08-18
AI Technical Summary
其二，在轧制变形时，板材宽度方向上存在不均匀变形，中部所受的压应力大于边部，导致中部变形量大于边部
本发明针对钛青铜合金带材热轧过程中因坯料上下表面温差、宽度方向变形不均导致的边部开裂问题，依托固溶后翻面处理、特定三角函数曲线大凸度凹型工作辊轧制，并适配相应的工艺方案（即850~900℃轧制温度与90%~95%变形量），从温度场和应力场协同优化，有效解决了现有工艺的技术缺陷，具体的，本发明的原理如下：固溶处理后的坯料在输送过程中，下表面会持续接触低温辊道散热降温，形成上下表面温度梯度，低温区域塑性变差，轧制时易在边部应力集中处产生裂纹，本发明通过固溶后坯料翻面操作，将低温下表面翻转至上方，避免其继续接触低温辊道持续失温，有效均衡坯料厚度方向的整体温度，消除温差引发的塑性不均与热应力问题，从源头降低边部开裂倾向。同时，本发明采用限定三角函数曲线构型的大凸度凹型工作辊开展多道次热轧，区别于常规轧辊轧制时板材中部变形量大、边部变形量小的不均匀状态，能够有效补偿坯料宽度方向的变形差异，提升带材边部变形量，抵消中部变形对边部产生的附加纵向拉应力，改善宽度方向应力分布不均的问题，抑制裂纹的萌生与扩展。在此基础上，850~900℃的轧制温度可保障钛青铜合金具备良好高温塑性，适配90%~95%的大变形量轧制需求，充分细化合金内部组织、消除内部应力缺陷，让温度均温和应力优化的技术效果充分发挥。本发明将翻面均温、凹型辊应力调控及适配的轧制参数有机结合，有效克服了现有单一调控方式无法彻底解决边部开裂的弊端，经试验验证，该工艺可完全消除钛青铜热轧带材边部开裂缺陷，显著提升带材成品质量与成材率，工艺适配现有生产设备，操作简便，能够有效提升钛青铜合金带材热轧生产的稳定性与生产效益。
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal material processing technology, and in particular relates to a hot rolling process for titanium bronze alloy strip, specifically a method for improving edge cracking of titanium bronze strip during hot rolling. Background Technology
[0002] Titanium bronze alloy is a typical high-strength, high-elasticity copper alloy. Due to its excellent comprehensive mechanical properties and good electrical conductivity, it is widely used in the manufacture of key components in precision instruments, electronics, and aerospace. However, during hot rolling, cracking is highly likely to occur at the edges of the lower surface of the strip, and these cracks often extend towards the center in the thickness direction, seriously affecting the yield, production efficiency, and the quality of the final product. The main reasons for this edge cracking problem are as follows: First, in multi-pass rolling, the rolled piece needs to be transported through the lower transport rollers between passes. During this process, the lower surface of the rolled piece is in continuous contact with the lower-temperature transport rollers, resulting in a significantly lower temperature on the lower surface compared to the upper surface, creating a temperature difference between the upper and lower surfaces. During subsequent rolling deformation, the lower surface, with its lower temperature, exhibits reduced plasticity, making it more prone to crack initiation at stress concentration points on the edges. Second, during rolling deformation, uneven deformation occurs in the width direction of the plate, with the compressive stress in the middle being greater than that at the edges, resulting in greater deformation in the middle than at the edges. This deformation inconsistency generates additional longitudinal tensile stress from the center of the sheet metal to the edges, thereby inducing and exacerbating edge cracking. Existing hot rolling processes typically do not effectively control temperature uniformity and stress distribution for high-strength, high-elasticity, and difficult-to-deform alloys like titanium bronze. Therefore, edge cracking has become one of the key technical bottlenecks restricting its efficient and high-quality production. Summary of the Invention
[0003] To address the problems existing in the prior art, the present invention aims to provide a method for improving edge cracking in hot-rolled titanium bronze strip. The present invention optimizes the operation process and roll configuration during rolling, effectively uniformizes the temperature distribution of the rolled piece and improves the stress state in the width direction, thereby significantly suppressing or even eliminating edge cracking and improving the yield and quality stability of hot-rolled titanium bronze strip.
[0004] To achieve the above objectives, the present invention adopts the following technical solution: A hot rolling process for titanium bronze alloy strip includes the following steps: The hot-forged titanium bronze alloy billet is subjected to solution treatment; The titanium bronze alloy billet after solution treatment is flipped over so that the upper surface of the titanium bronze alloy billet after solution treatment becomes the lower surface. The titanium bronze alloy billet after being flipped is hot rolled in multiple passes using concave work rolls with increased roll convexity. During the rolling process, the deformation of the titanium bronze alloy billet is 90%~95%, and the rolling temperature is 850~900℃. The roll profile curve of the concave work roll with increased roll crown is a trigonometric function curve, and the roll profile curve of the concave work roll is as follows:
[0005] In the formula, α is the original diameter of the concave work roll, b is the amplitude of the cosine function, and α is the wrap angle of the cosine function. This refers to the length of the concave work roll body.
[0006] Preferably, when solution treating the hot-forged titanium bronze alloy billet, the solution temperature is 850~900℃, the holding time is 30~60 minutes, and the flipping operation is performed directly after the holding time is completed.
[0007] Preferably, when performing solution treatment on hot-forged titanium bronze alloy billets, the heating rate is controlled at 10~15℃ / min.
[0008] Preferably, a box furnace or atmosphere furnace is used to perform solution treatment on the hot-forged titanium bronze alloy billet.
[0009] Preferably, the chemical composition of the titanium bronze alloy billet, by weight percentage, includes: Ti 2.6%~4.5%, with the balance being Cu and unavoidable impurities.
[0010] Preferably, the thickness of the titanium bronze alloy blank is 90mm to 200mm.
[0011] Preferably, the multi-pass hot rolling is a multi-roll continuous rolling process.
[0012] Preferably, the deformation passes of the multi-pass hot rolling are 12 to 16 passes.
[0013] Preferably, the reduction rate of each pass in the multi-pass hot rolling is controlled at 16%-21%.
[0014] Preferably, the concave working roller has a roll crown of 0.25 mm, an edge radius of 400 mm, a center radius of 399.75 mm, and a width of 600 mm.
[0015] The present invention has the following beneficial effects: This invention addresses the edge cracking problem caused by temperature differences between the upper and lower surfaces of the billet and uneven deformation in the width direction during the hot rolling of titanium bronze alloy strip. It utilizes post-solution turning treatment, rolling with high-convexity concave work rolls featuring a specific trigonometric function curve, and an appropriate process scheme (i.e., rolling temperature of 850~900℃ and deformation of 90%~95%) to synergistically optimize the temperature and stress fields, effectively solving the technical defects of existing processes. Specifically, the principle of this invention is as follows: During the conveying process, the lower surface of the billet after solution treatment continuously contacts the low-temperature roller table for heat dissipation, forming a temperature gradient between the upper and lower surfaces. The plasticity deteriorates in the low-temperature region, making it prone to cracking at the edge stress concentration points during rolling. This invention, through the post-solution billet turning operation, flips the low-temperature lower surface to the top, preventing it from continuing to contact the low-temperature roller table and losing heat. This effectively balances the overall temperature in the thickness direction of the billet, eliminating the uneven plasticity and thermal stress problems caused by temperature differences, and reducing the tendency for edge cracking from the source. Meanwhile, this invention employs a high-convex concave work roll with a defined trigonometric function curve configuration for multi-pass hot rolling. This differs from conventional roll rolling, which results in uneven deformation at the edges and a large deformation in the center of the sheet. This effectively compensates for deformation differences along the width of the billet, increases edge deformation, offsets the additional longitudinal tensile stress generated by center deformation, improves uneven stress distribution along the width, and inhibits crack initiation and propagation. Furthermore, a rolling temperature of 850~900℃ ensures that the titanium bronze alloy possesses good high-temperature plasticity, adapting to the rolling requirements of 90%~95% large deformation, fully refining the alloy's internal structure, eliminating internal stress defects, and allowing the technical effects of temperature uniformity and stress optimization to be fully realized. This invention organically combines the temperature equalization of flipping, the stress control of concave rolls, and the appropriate rolling parameters, effectively overcoming the shortcomings of existing single control methods that cannot completely solve the problem of edge cracking. Experimental verification shows that this process can completely eliminate edge cracking defects in hot-rolled titanium bronze strip, significantly improve the quality and yield of finished strip, adapt to existing production equipment, and is easy to operate, effectively improving the stability and production efficiency of hot-rolled titanium bronze alloy strip. Attached Figure Description
[0016] Figure 1 The image shows a photograph of a titanium bronze alloy strip rolled using the method described in Example 1 of this invention.
[0017] Figure 2 A photograph of a titanium bronze alloy strip rolled using the method of this invention.
[0018] Figure 3 This is a schematic diagram of the concave working roller used in an embodiment of the present invention. Detailed Implementation
[0019] The present invention will be further described clearly and in detail below with reference to specific embodiments and the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.
[0020] The present invention provides a method for improving edge cracking in hot-rolled titanium bronze strip, comprising the following steps: Step 1: Solution treatment is performed on the hot-forged titanium bronze alloy billet at a temperature of 850~900℃ and a holding time of 30~60 minutes. Step 2: Take out the titanium bronze alloy billet after the solution treatment in Step 1 and flip it over directly, so that the original upper surface of the titanium bronze alloy billet becomes the lower surface, and then feed it into the rolling mill through the roller table. Step 3: During the rolling process, the working rolls of the rolling mill are concave working rolls with increased roll crown, and multiple hot rolling passes are performed to obtain the titanium bronze alloy strip of the final size.
[0021] Specifically, based on the above-mentioned scheme of the present invention, titanium bronze alloys with the following composition can be rolled. The chemical composition of the titanium bronze alloy, by weight percentage, includes: Ti 2.6%~4.5%, with the balance being Cu and unavoidable impurities. In the following embodiments and comparative examples of the present invention, the chemical composition of the titanium bronze alloy, by weight percentage, includes: Ti 4.0%, Cu 95.91%, with the balance being impurities. During the solution treatment, the forged sample is heated to 850~900℃ using a box furnace or atmosphere furnace, with the heating rate controlled at 10~15℃ / min. During the rolling process, the billet thickness is rolled from 90mm~200mm to 5.5mm~13.3mm, the deformation is 90%~95%, and the rolling temperature is 850~900℃. The multi-pass hot rolling is a multi-roll continuous rolling process, with 12~16 deformation passes, and the reduction rate per pass is controlled at 16%~21%. The roll profile curve of the concave rolls used in the rolling mill adopts a trigonometric function curve, and the roll profile curve of the work rolls is as follows:
[0022] In the formula, Where is the original diameter of the work roll, b is the amplitude of the cosine function, and α is the wrap angle of the cosine function. This refers to the length of the work roll body.
[0023] See Figure 3The working roll parameters used in the following embodiments and comparative examples of the present invention are as follows: the working roll crown is 0.25 mm, the roll edge radius is 400 mm, the center radius is 399.75 mm, and the width is 600 mm.
[0024] Example 1 This embodiment describes a method for improving edge cracking in hot-rolled titanium bronze strip, comprising the following steps: Step 1: Take hot-forged titanium bronze alloy as the base material, with a thickness of 90 mm and a width of 400 mm.
[0025] Step 2: Solution treatment of hot-forged titanium bronze alloy billet: heating rate controlled at 10℃ / min, solution temperature at 850℃, and holding time at 60 minutes; Step 3: Take out the solution-treated sample and turn it over so that the original upper surface becomes the lower surface; Step 4: Multi-pass hot rolling is performed using concave work rolls; wherein the work roll crown is 0.25mm, the roll edge radius is 400mm, the center radius is 399.75mm, the width is 600mm, the rolling passes are 16, the reduction rate of each pass is controlled at 16%, the billet thickness is rolled from 90mm to 5.5mm during the rolling process, the deformation is 94%, and the rolling temperature is 850℃; Rolling results as follows Figure 1 As shown, there is no obvious cracking at the edge of the rolled piece.
[0026] Example 2 This embodiment describes a method for improving edge cracking in hot-rolled titanium bronze strip, comprising the following steps: Step 1: Take hot-forged titanium bronze alloy as the base material, with a thickness of 150 mm and a width of 400 mm.
[0027] Step 2: Solution treatment of hot-forged titanium bronze alloy billet: heating rate controlled at 12℃ / min, solution temperature at 880℃, and holding time at 45 minutes; Step 3: Take out the solution-treated sample and turn it over so that the original upper surface becomes the lower surface; Step 4: Multi-pass hot rolling is performed using concave work rolls; wherein the work roll crown is 0.25mm, the roll edge radius is 400mm, the center radius is 399.75mm, the width is 600mm, the rolling passes are 14, the reduction rate of each pass is controlled at 18%, the billet thickness is rolled from 150mm to 9.3mm during the rolling process, the deformation is 93.8%, and the rolling temperature is 880℃; The rolled workpiece showed no obvious cracking at the edges.
[0028] Example 3 This embodiment describes a method for improving edge cracking in hot-rolled titanium bronze strip, comprising the following steps: Step 1: Take hot-forged titanium bronze alloy as the base material, with a thickness of 90 mm and a width of 400 mm.
[0029] Step 2: Solution treatment of hot-forged titanium bronze alloy billet: heating rate controlled at 15℃ / min, solution temperature at 900℃, and holding time at 30 minutes; Step 3: Take out the solution-treated sample and turn it over so that the original upper surface becomes the lower surface; Step 4: Multi-pass hot rolling is performed using concave work rolls; wherein the work roll crown is 0.25mm, the roll edge radius is 400mm, the center radius is 399.75mm, the width is 600mm, the rolling passes are 12, the reduction rate of each pass is controlled at 21%, the billet thickness is rolled from 90mm to 5.5mm during the rolling process, the deformation is 94%, and the rolling temperature is 900℃; The rolled workpiece showed no obvious cracking at the edges.
[0030] Example 4 This embodiment describes a method for improving edge cracking in hot-rolled titanium bronze strip, comprising the following steps: Step 1: Take hot-forged titanium bronze alloy as the base material, with a thickness of 200 mm and a width of 400 mm.
[0031] Step 2: Solution treatment of hot-forged titanium bronze alloy billet: heating rate controlled at 10℃ / min, solution temperature at 850℃, and holding time at 60 minutes; Step 3: Take out the solution-treated sample and turn it over so that the original upper surface becomes the lower surface; Step 4: Multi-pass hot rolling is performed using concave work rolls; wherein the work roll crown is 0.25 mm, the roll edge radius is 400 mm, the center radius is 399.75 mm, the width is 600 mm, the rolling passes are 12, the reduction rate of each pass is controlled at 20%, the billet thickness is rolled from 200 mm to 13.7 mm during the rolling process, the deformation is 93.1%, and the rolling temperature is 850℃; The rolled workpiece showed no obvious cracking at the edges.
[0032] Comparative Example This comparative example is basically the same as Example 1, except that: no flipping treatment was performed after solution treatment, and no concave rolls were used for rolling. The parameters of the comparative work rolls are: radius 400 mm, width 600 mm. Under the same rolling process, obvious cracks appeared on the edge of the lower surface of the rolled strip, such as... Figure 2As shown in Example 1, this comparative example demonstrates that by introducing a flipping operation and using concave work rolls, the problem of uneven plasticity caused by temperature differences between the upper and lower surfaces can be solved, the stress distribution in the rolling deformation zone can be optimized, and the tensile stress that causes edge cracking can be offset. The synergistic effect of these two methods effectively controls edge cracking defects in hot-rolled titanium bronze alloys without significantly increasing equipment complexity or production costs.
[0033] As can be seen from the results of the above embodiments and comparative examples, the technical solution of the present invention has the following characteristics: (1) The present invention uses a flipping operation after heat treatment to turn the original lower surface into the upper surface, thus preventing it from continuing to contact the conveyor roller and further cooling down. This measure effectively promotes the uniformity of the thickness direction temperature of the rolled piece throughout the rolling process, reduces the thermal stress and plasticity unevenness caused by the large temperature difference between the upper and lower surfaces, and fundamentally alleviates the tendency of edge cracking caused by local low temperature.
[0034] (2) The present invention uses concave rollers for rolling, which compensates for the additional tensile stress generated at the edge due to uneven deformation in the width direction. This convex configuration can increase the amount of edge deformation, actively improve the stress distribution in the width direction of the plate, make the deformation more uniform, thereby effectively offsetting or weakening the tensile stress effect of the middle on the edge, and inhibiting the initiation and expansion of edge cracks.
[0035] (3) This invention combines two methods: heat treatment followed by flipping and concave rollers. By working synergistically from both temperature and stress fields, it addresses the complex problem of edge cracking in hot-rolled titanium bronze. This method is targeted, easy to promote, and can significantly improve the stability and economic benefits of hot-rolling production of difficult-to-deform alloys such as titanium bronze.
[0036] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.
[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.
Claims
1. A hot rolling process for titanium bronze alloy strip, characterized in that, The process includes the following: The hot-forged titanium bronze alloy billet is subjected to solution treatment; The titanium bronze alloy billet after solution treatment is flipped over so that the upper surface of the titanium bronze alloy billet after solution treatment becomes the lower surface. The titanium bronze alloy billet after being flipped is hot rolled in multiple passes using concave work rolls with increased roll convexity. During the rolling process, the deformation of the titanium bronze alloy billet is 90%~95%, and the rolling temperature is 850~900℃. The roll profile curve of the concave work roll with increased roll crown is a trigonometric function curve, and the roll profile curve of the concave work roll is as follows: In the formula, α is the original diameter of the concave work roll, b is the amplitude of the cosine function, and α is the wrap angle of the cosine function. This refers to the length of the concave work roll body.
2. The hot rolling process for titanium bronze alloy strip according to claim 1, characterized in that, When solution treating hot-forged titanium bronze alloy billets, the solution temperature is 850~900℃, the holding time is 30~60 minutes, and the billets are turned over directly after the holding time is completed.
3. The hot rolling process for titanium bronze alloy strip according to claim 1, characterized in that, When solution treating hot-forged titanium bronze alloy billets, the heating rate is controlled at 10~15℃ / min.
4. The hot rolling process for titanium bronze alloy strip according to claim 1, characterized in that, When solution treating hot-forged titanium bronze alloy billets, a box furnace or atmosphere furnace is used.
5. The hot rolling process for titanium bronze alloy strip according to claim 1, characterized in that, The chemical composition of the titanium bronze alloy billet, by weight percentage, includes: Ti 2.6%~4.5%, with the balance being Cu and unavoidable impurities.
6. The hot rolling process for titanium bronze alloy strip according to claim 1, characterized in that, The thickness of the titanium bronze alloy billet is 90mm~200mm.
7. The hot rolling process for titanium bronze alloy strip according to claim 1, characterized in that, The multi-pass hot rolling is a multi-roll continuous rolling process.
8. The hot rolling process for titanium bronze alloy strip according to claim 1, characterized in that, The deformation passes in the multi-pass hot rolling process are 12 to 16.
9. The hot rolling process for titanium bronze alloy strip according to claim 1, characterized in that, The reduction rate of each pass in the multi-pass hot rolling is controlled at 16%-21%.
10. The hot rolling process for titanium bronze alloy strip according to claim 1, characterized in that, The concave working roller has a roll crown of 0.25 mm, an edge radius of 400 mm, a center radius of 399.75 mm, and a width of 600 mm.