Method for preventing stress cracking of high-alloy tool steel belt
By controlling the parameters of heating, hot rolling, and cooling processes, and combining them with slow cooling treatment, the stress cracking problem of high alloy tool steel strip during cold rolling was solved, thereby improving product integrity and yield.
Patent Information
- Application Number
- CN202511556809.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-29
- Publication Date
- 2026-02-06
AI Technical Summary
High-alloy tool steel strip is prone to stress cracking during cold rolling, which affects product quality and yield, and existing technologies are unable to effectively solve this problem.
By controlling the heating temperature and holding time in the billet heating process, the final rolling temperature in the hot rolling process, and the coiling temperature in the coiling process, and by adopting a slow cooling process in the pit, including a heating temperature of 1150-1230℃, a holding time of not less than 100 minutes, a final rolling temperature of 950℃ or higher, a coiling temperature of 500℃ or higher, and a slow cooling time of not less than 48 hours, the diffusion of alloying elements is improved and residual stress is reduced.
It effectively prevents stress cracking of high alloy tool steel strip during cold rolling, improving product integrity and yield.
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of high alloy tool steel strip, in particular to a method for preventing stress cracking of high alloy tool steel strip. BACKGROUND
[0002] High alloy tool steel strip contains a high proportion of alloying elements (such as Cr, Ni, Mo, V, etc.), has excellent properties such as high hardness, high wear resistance, high thermal stability, and is widely used in the fields of cutters, blades, electronic components, etc. However, this type of material also has the characteristics of low toughness and strong stress sensitivity, and stress cracking occurs during subsequent cold rolling process, which becomes a key problem affecting product quality, yield and processing difficulty.
[0003] The causes of stress cracking of high alloy tool hot-rolled narrow strip steel include multiple aspects: first, due to high alloy content, it is difficult to control the uniformity of the composition, and composition segregation is easy to occur; second, too high alloy elements will lead to the formation of brittle phase at the grain boundary, reducing the grain boundary bonding force; third, if the deformation amount is too large and the deformation temperature is too low during rolling, residual stress will be formed in the material; finally, if the cooling speed after rolling is too fast, the temperature difference between the inside and outside of the strip is too large, and a large thermal stress will be generated.
[0004] In summary, solving the problem of stress cracking of high alloy tool steel strip is the key to further improving product competitiveness. SUMMARY
[0005] The present application is aimed at the above technical problems, overcomes the shortcomings of the prior art, and provides a method for preventing stress cracking of high alloy tool steel strip, solving the problem of stress cracking of high alloy tool steel strip during subsequent cold rolling process.
[0006] The method for preventing stress cracking of high alloy tool steel strip in the present application includes steel billet heating process, hot rolling process, coiling process and cooling process in sequence, by controlling the heating temperature and holding time in the steel billet heating process, the finishing temperature in the hot rolling process, the coiling temperature in the coiling process, and adopting the pit cooling method to perform the cooling process, to solve the problem of stress cracking of high alloy tool steel strip during subsequent cold rolling process.
[0007] The further defined technical solution of the present application is: Further, in the steel billet heating process, the heating temperature of the steel billet in the high temperature section is controlled to be 1150-1230℃, and the holding time of the steel billet in the high temperature section is not less than 100 minutes.
[0008] Further, in the hot rolling process, the finishing temperature of the hot rolling is controlled to be above 950℃.
[0009] Further, in the coiling process, the coiling temperature is controlled to be above 500℃.
[0010] Further, in the cooling process, the high alloy tool steel strip after coiling is sent to the slow cooling pit for slow cooling, and the slow cooling time of the high alloy tool steel strip in the slow cooling pit is not less than 48 hours.
[0011] Further, before the high alloy tool steel strip is sent to the slow cooling pit, the temperature of the slow cooling pit is heated to above 200 DEG C.
[0012] The beneficial effects of the present application are: The method for preventing stress cracking of high alloy tool steel strip provided by the present application provides sufficient heating temperature and holding time, can effectively realize high temperature diffusion of alloy elements, improve the internal uniformity of the billet, avoid the formation of brittle phase at the grain boundary, use higher rolling temperature to reduce the formation of residual stress in the steel strip, higher coiling temperature ensures the temperature drop of the steel strip on the flat chain, reduces the generation of thermal stress, and through the slow cooling in the pit, the cooling rate of the steel strip can be further slowed down, solving the problem of stress cracking of high alloy tool steel strip in the subsequent cold rolling process. DETAILED DESCRIPTION
[0013] The present application discloses a method for preventing stress cracking of high alloy tool steel strip, including billet heating, hot rolling, coiling and cooling process, by controlling the heating temperature and holding time in the billet heating process, the finishing temperature in the hot rolling process, the coiling temperature in the coiling process, and adopting the slow cooling in the pit to perform the cooling process, to solve the problem of stress cracking of high alloy tool steel strip in the subsequent cold rolling process.
[0014] Taking X32 hot-rolled narrow strip steel with a thickness of 3.5 mm and a width of 374 mm as an example. The heating temperature and holding time of the billet are controlled, the heating temperature in the high temperature section is controlled at 1208 DEG C, and the holding time in the high temperature section is 153 minutes, further, the finishing temperature of hot rolling is controlled at above 961 DEG C, the coiling temperature is controlled at above 611 DEG C, the steel strip needs to enter the slow cooling pit for slow cooling, and the slow cooling time is not less than 48 hours. Before the high alloy tool steel strip enters the pit, the temperature of the slow cooling pit is heated to above 234 DEG C.
[0015] Before the process is improved, the X32 steel strip appears stress cracking phenomenon at a distance of 10 meters from the head in the cold rolling process, and the improved steel strip of the same steel grade and specification is complete without cracking.
[0016] In addition to the above embodiments, the present application can have other embodiments. Any technical solution formed by equivalent substitution or equivalent transformation falls within the protection scope required by the present application.
Claims
1. A method for preventing stress cracking in high-alloy tool steel, characterized in that, The process includes sequential billet heating, hot rolling, coiling, and cooling. By controlling the heating temperature and holding time in the billet heating process, the final rolling temperature in the hot rolling process, and the coiling temperature in the coiling process, and by using a slow cooling method in the pit to perform the cooling process, the problem of stress cracking of high alloy tool steel strip during subsequent cold rolling is solved.
2. The method for preventing stress cracking in high-alloy tool steel according to claim 1, characterized in that, In the billet heating process, the heating temperature of the billet in the high-temperature section is controlled at 1150-1230℃, and the holding time of the billet in the high-temperature section is not less than 100 minutes.
3. The method for preventing stress cracking in high-alloy tool steel according to claim 1, characterized in that, In the hot rolling process, the final rolling temperature is controlled to be above 950℃.
4. The method for preventing stress cracking in high-alloy tool steel according to claim 1, characterized in that, During the winding process, the winding temperature is controlled to be above 500℃.
5. The method for preventing stress cracking in high-alloy tool steel according to claim 1, characterized in that, In the cooling process, the high-alloy tool steel strip after being coiled is sent into a slow cooling pit for slow cooling, and the slow cooling time of the high-alloy tool steel strip in the slow cooling pit is not less than 48 hours.
6. The method for preventing stress cracking in high-alloy tool steel according to claim 1, characterized in that, Before feeding the high-alloy tool steel strip into the slow cooling pit, the temperature of the slow cooling pit is first heated to above 200°C.