中文版 中文版  |   EnglishEnglish
搜索
Search

NEWS

/
/
/
Roll manufacturing tells you about the knowledge of rolls

News

Roll manufacturing tells you about the knowledge of rolls

  • Time of issue:2022-10-13 11:02

Roll manufacturing tells you about the knowledge of rolls

  • Time of issue:2022-10-13 11:02
  • Views:
Information

What causes        the roll to break ? Let's talk about roll manufacturing .

Xxv_xNxIRHyewklWp-q2Hw.jpg

1. Brittle fracture, the fracture shape of this roll is relatively flat, and the surface of the roll body around the fracture is relatively neat;

    2. Ductile fracture. The fracture shape of this kind of roller is mostly 'mushroom head', and the roller body near the fracture is crushed. Through comparison, it is found that the broken roll accident belongs to ductile fracture. Both brittle and ductile fractures are caused by the stress of the roll exceeding the strength of the core. The reason is related to the residual stress of the roll itself, the mechanical stress during rolling and the thermal stress of the roll, especially when the temperature difference between the surface of the roll body and the core is large. This temperature difference can be caused by poor roll cooling, interruptions in cooling, or overheating of the roll surface at the start of a new rolling cycle. This huge temperature difference between the roll surface and the roll core causes a lot of thermal stress, and when the huge thermal stress, mechanical stress and residual stress of the roll exceed the strength of the roll core, the roll will break. For example, when the temperature difference between the surface of the roll and the core is 70°C, the longitudinal thermal stress of the roll will increase by 100MPa. The greater the temperature difference, the greater the increased thermal stress. Compared with the brittle fracture roll, the core material of the ductile fracture roll has better toughness and is not easy to break. Roll manufacturers understand that there are four types of stress that can cause a roll to fail:

  1. Residual stress in the manufacturing process;

  2. Mechanical stress during rolling;

  3. The structural stress of the roll during rolling;

4. Thermal stress caused by temperature difference inside and outside the roll.

  According to roll manufacturing , the main links in the cold roll manufacturing process include smelting, forging, heat treatment, processing and inspection.

  According to roll manufacturing , cold rolls are subjected to great rolling stress during the working process. Problems such as welds, inclusions, and edge cracks in the rolled piece are likely to cause instantaneous high temperature, which makes the work rolls subject to strong thermal shock, resulting in cracks, roll sticking, Peeling or even scrapping. Therefore, cold rolled rolls should have the ability to resist cracking and spalling caused by bending stress, torsional stress and shear stress, and should also have high wear resistance, high contact fatigue strength, high fracture toughness and thermal shock strength. Therefore, how to improve the service life of rolls has always been a major problem faced by the roll manufacturing industry.

  According to the roll manufacturer , the non-destructive testing of rolls is usually carried out by ultrasonic flaw detectors. In the cold roll flaw detection standard, the roll identity is usually divided into the surface area, the central area and the middle area according to the stress, and then the critical size of the allowable defect in each area is stipulated according to the principle of fracture mechanics. Inspectors should have knowledge of roll manufacturing in order to judge the nature of defects, and also have knowledge of roll use in order to estimate whether these defects may cause service injuries under specific service conditions.

Our roll manufacturing has many years of experience in this industry, and has established a scientific and standardized production management system to support the development of products and markets with high-tech content. Welcome to contact us.

 

There is currently no information to display
Please add data record on website background.
产品分类

Lianqiang metallurgical roll

Add: No. 8 Guofeng Street, Fengnan District, Tangshan City, Hebei Add: Liucheng Economic Development Zone, Chaoyang City, Liaoning Province
Phone:
13722533381
E-mail: sales@lianqiang.com

Domestic business contacts: Wang Lili, Xu Xiaoqian, Li Weikai
Mobile WeChat synchronization: 13333295129 19912326376 18731995853
Contact person for export business: Liu Zhuzhu
Mobile WeChat synchronization: 13832886863
Fax: 0315-8129356 8112576 0421-7021209

Lianqiang

 WeChat

Copyright ©Tangshan Lianqiang metallurgical roll Co., Ltd   冀ICP备08102597号   300.cn Tangshan

Copyright ©2021 Tangshan Lianqiang metallurgical roll Co., Ltd

冀ICP备08102597号   300.cn Tangshan