阅读说明：本技术 锻钢冷轧辊深冷处理方法及其采用的新型喷嘴 (Cryogenic treatment method for forged steel cold roll and novel nozzle adopted by cryogenic treatment method ) 是由 陈伟 乔建平 丁贵擎 兰勇 罗昌 崔海峰 侯兴慧 于 2019-10-31 设计创作，主要内容包括：本发明公开了一种锻钢冷轧辊深冷处理方法及其采用的新型喷嘴,喷嘴具有安装部和喷嘴头,喷嘴头上设有1个直径为0.8～1.2mm的大喷口以及若干个设置在大喷口四周的直径为0.4～0.6mm的小喷口；深冷处理方法如下：①将锻钢冷轧辊置于深冷箱中,关闭深冷箱；②将液氮从喷嘴喷入深冷箱内,并通过1～2h将深冷箱内的温度降至-160～-120℃；③在该温度下保温2～5h；④保温结束后,打开深冷箱,将锻钢冷轧辊置于室温环境下,自然恢复至室温。本发明通过设计一种新型喷嘴并匹配相应的深冷处理方法,能够使喷出的液氮更分散、更均匀,从而使得锻钢冷轧辊表面硬度更均匀,成品硬度均匀性,而喷嘴堵塞现象也是大大减少。(The invention discloses a cryogenic treatment method of a forged steel cold roll and a novel nozzle adopted by the cryogenic treatment method, wherein the nozzle is provided with an installation part and a nozzle head, the nozzle head is provided with 1 large nozzle with the diameter of 0.8-1.2 mm and a plurality of small nozzles with the diameter of 0.4-0.6 mm arranged around the large nozzle, the cryogenic treatment method comprises the steps of ① placing the forged steel cold roll in a cryogenic box, closing the cryogenic box, ② spraying liquid nitrogen into the cryogenic box from the nozzle, reducing the temperature in the cryogenic box to-160-120 ℃ through 1-2 h, ③ preserving the temperature for 2-5 h at the temperature, after ④ preserving the temperature, opening the cryogenic box, placing the forged steel cold roll in a room temperature environment, and naturally recovering to the room temperature.)

1. A cryogenic treatment method for a forged steel cold roll is characterized by comprising the following steps:

① placing the cold roll of forged steel in a cryogenic box, closing the cryogenic box;

②, spraying liquid nitrogen into the cryogenic box from a nozzle, and reducing the temperature in the cryogenic box to-160 to-120 ℃ after 1-2 hours;

③ is kept at the temperature of-160 to-120 ℃ for 2 to 5 hours;

④ after the heat preservation is finished, opening the cryogenic box, placing the forged steel cold roll in the room temperature environment, and naturally recovering to the room temperature;

in the step ②, the nozzle is provided with an installation part (1) and a nozzle head (2), the installation part (1) comprises a threaded connection part (11) and a hexagon screw rotating part (12), and the nozzle head (2) is provided with 1 large nozzle (21) and a plurality of small nozzles (22) arranged around the large nozzle (21).

2. The cryogenic treatment method for the cold roll of forged steel according to claim 1, characterized by comprising the following steps: the diameter of the large nozzle (21) is 0.8-1.2 mm, and the diameter of the small nozzle (22) is 0.4-0.6 mm.

3. The cryogenic treatment method for the cold roll of forged steel according to claim 1 or 2, characterized by comprising the following steps: the cavity (3) inside the nozzle is 5.5-7 mm.

4. A novel nozzle adopted by the cryogenic treatment method for the forged steel cold roll according to claim 1, which is provided with an installation part (1) and a nozzle head (2), wherein the installation part (1) comprises a threaded connection part (11) and a hexagon screw rotating part (12), and is characterized in that: the nozzle head (2) is provided with 1 large nozzle (21) and a plurality of small nozzles (22) arranged around the large nozzle (21).

5. The novel nozzle of claim 4, wherein: the diameter of the large nozzle (21) is 0.8-1.2 mm, and the diameter of the small nozzle (22) is 0.4-0.6 mm.

6. The novel nozzle of claim 4 or 5, characterized in that: the cavity (3) inside the nozzle is 5.5-7 mm.

Technical Field

The invention belongs to the technical field of cryogenic treatment, and particularly relates to a cryogenic treatment method for a forged steel cold roll and a novel nozzle adopted by the cryogenic treatment method.

Background

The forged steel cold roll is the most important part of a rolling mill in a cold rolling mill, most of the cold roll manufacturing process is subjected to cryogenic treatment, which is an extension of the cold roll heat treatment cooling process, and the cryogenic treatment is to place the cold roll in a specific low-temperature environment to change the microstructure of the cold roll so as to achieve the purpose of improving the comprehensive performance of the cold roll.

At present, the cryogenic treatment of the forged steel cold roll mainly adopts a liquid nitrogen direct spraying mode, and the cryogenic treatment equipment mainly comprises: the system comprises a liquid nitrogen storage tank, a cryogenic tank, a liquid nitrogen spray pipe and nozzle, an ultralow temperature electromagnetic valve and a control system.

At present, the problems of the direct liquid nitrogen spraying cryogenic treatment mode are as follows: the hardness uniformity of the finished product is poor, and the applicant finds that the problem is greatly related to the existing liquid nitrogen nozzle structure through a large amount of research.

As shown in figures 1-2, the conventional liquid nitrogen nozzle structure comprises a mounting part 1 'and a nozzle head 2', wherein the mounting part 1 'comprises a threaded connection part 11' and a hexagon screw rotating part 12 ', only 1 nozzle 21' with the diameter of about 2mm is arranged on the nozzle head 2 ', and a cavity 3' in the nozzle is only about 4 mm. The liquid nitrogen sprayed out by the nozzle is concentrated, the cooling strength is high, the temperature of the local area of the forged steel cold roll is low, so that a soft belt and even cracks are generated, and the nozzle blockage phenomenon is easy to generate.

Chinese patent document CN103468918A discloses a method for spraying liquid nitrogen into a fine mist by installing a mesh at the nozzle of a liquid nitrogen spray pipe, however, this method does not solve the above problems well.

Disclosure of Invention

The invention aims to solve the problems and provides a cryogenic treatment method for a forged steel cold roll, which can effectively improve the hardness uniformity of a forged steel cold roll finished product, and a novel nozzle adopted by the cryogenic treatment method.

The technical scheme for achieving the purpose of the invention is that the cryogenic treatment method of the forged steel cold roll comprises the following steps of ① placing the forged steel cold roll in a cryogenic box, closing the cryogenic box, ② spraying liquid nitrogen into the cryogenic box from a nozzle, reducing the temperature in the cryogenic box to-160 to-120 ℃ through 1-2 hours, ③ preserving heat for 2-5 hours at the temperature of-160 to-120 ℃, opening the cryogenic box after ④ preserving heat, and naturally recovering the forged steel cold roll to the room temperature under the environment of the room temperature (15-25 ℃ and the same below).

The novel nozzle that above-mentioned forged steel cold roll cryogenic treatment method adopted has installation department and nozzle head, the installation department includes threaded connection portion and hex bolts rotating part, it sets up to be equipped with 1 big spout and a plurality of on the nozzle head big spout little spout all around.

The diameter of the large nozzle is 0.8-1.2 mm, and the diameter of the small nozzle is 0.4-0.6 mm.

The cavity inside the nozzle is 5.5-7 mm.

The invention has the following positive effects: by designing a novel nozzle and matching with a corresponding cryogenic treatment method, the sprayed liquid nitrogen can be dispersed and uniform, so that the surface hardness of the forged steel cold roll is uniform, the hardness uniformity of a finished product is greatly improved, and the nozzle blockage phenomenon is also greatly reduced.

Drawings

Fig. 1 is a schematic structural view of a conventional liquid nitrogen nozzle.

Fig. 2 is a right side view of fig. 1.

FIG. 3 is a schematic view of the structure of the liquid nitrogen nozzle of the present invention.

Fig. 4 is a right side view of fig. 3.

FIG. 5 is a graph of the cooling process of the cryogenic treatment of example 1.

Detailed Description

(example 1)

Referring to fig. 3 and 4, the novel nozzle of the present embodiment has a mounting portion 1 and a nozzle head 2, the mounting portion 1 includes a threaded connection portion 11 and a hexagon screw rotating portion 12, a cavity 3 inside the nozzle can reach 6mm, and the nozzle head 2 is provided with 1 large nozzle 21 having a diameter of about 1mm and a plurality of small nozzles 22 having a diameter of about 0.5mm and disposed around the large nozzle 21.

The cryogenic treatment method of the embodiment is as follows:

① the cold roll of forged steel is first placed in the cryogenic box and the cryogenic box is closed.

② controlling the ultralow temperature electromagnetic valve by the control system, spraying liquid nitrogen into the cryogenic box from the liquid nitrogen storage tank through the liquid nitrogen spray pipe and the spray nozzle, and reducing the temperature in the cryogenic box to-140 +/-1 ℃ for 1.5 h;

③ is kept at 140 ℃ below zero plus or minus 1 ℃ for 3.5h, and the temperature in the box is kept unchanged by spraying liquid nitrogen in the cryogenic box during the heat preservation process.

④ after the heat preservation is finished (total 5 h), the cryogenic box is opened, and the forged steel cold roll is placed in the room temperature environment and naturally returns to the room temperature.

The cooling process curve of the cryogenic treatment of the embodiment is shown in figure 5.