Why 400 series stainless steel is annealed in bell type furnace?

Why 400 series stainless steel is annealed in bell type furnace?

After the stainless steel is cold rolled by a 20 high mill, it needs to be annealed to repair the new mechanical properties. Why 400 series stainless steel is annealed in bell type furnace? The following is the simplest and most direct explanation.

400 series stainless steel generally refers to ferritic stainless steel. The annealing process is to raise the temperature and slowly cool to prevent the production of martensite;

300 series stainless steel generally refers to austenitic stainless steel, which is rapidly cooled with water or water mist after being heated in a continuous furnace to make the carbon element dissolve into the matrix, also known as solution treatment. If the bell type furnace is used, the cooling speed cannot keep up with it, and carbon precipitates at the grain boundary, and the strip steel becomes hard. It can not achieve the purpose of annealing.
20 high rolling mill, bell type annealing process, 400 stainless steel
 

Foshan Glimpse Engineering Technology Co., Ltd. (Glimpse Technology for short, its predecessor is Xi'an Weibao Metallurgical Equipment Technology Co., Ltd. established in 2014) is located in Foshan, the main distribution hub of stainless steel in China and Glimpse’s headquarter office is located in Foshan Greenland Financial Complex Building. Glimpse is a high-tech company with a team of top metallurgical experts in China, specializing in development, design, manufacture, installation and commissioning of complete sets of cold rolling equipment and strip processing equipment for stainless steel, carbon steel and non-ferrous metals. Glimpse has a professional team of 40 experts and technicians which including 2 well-known steel rolling expert professors (appointed consultants), 4 well-known foreign steel rolling experts (appointed consultants), 8 professor-level senior engineers, 10 senior engineers, and the rest are master degree holders or experienced technicians with medium-grade or above professional titles. Glimpse masters the core technologies of metallurgical fields: cold rolling, tandem cold rolling, annealing, pickling etc. Glimpse cooperates with world first-class professional companies, university research institutes (such as China North Heavy Industries Group, Sinosteel West Heavy, MCC Shaanxi) Press, China Second Heavy, Xi'an University of Technology, Yanshan University, Germany ABB, Germany Siemens, etc.) for long-term strategic cooperation.

Glimpse provides domestic and oversea steel plants with professional strip cold rolling, strip processing equipment and engineering services. 

Cold rolling equipment includes: provides 20-high reversible cold rolling mills, 18-high reversible cold rolling mills, four-high reversible cold rolling mills, six-high reversible cold rolling mills, carbon steel tandem rolling mills, and stainless steel tandem rolling mills for domestic and oversea steel plants.

Strip processing equipment includes: galvanzing and coating line, continuous annealing furnace, pickling line, tension leveller, 23-roll tension leveller, recoiler, skin pass mill, silicon steel processing line and other processing lines.

Engineering services includes: design, engineering, installation, commissioning and training for strip milling and processing equipment. Since its establishment, Glimpse has won royal customers at home and abroad through good performance and reputation in the industry. Customers spread in Guangdong, Guangxi, Shandong, Jiangsu, Zhejiang, Fujian, Shaanxi, Anhui, and other regions as well as India, Indonesia, Russia and other countries. Glimpse wholeheartedly provides customers with high-quality technology, equipment and engineering services, and cooperates with customers and partners to achieve a win-win situation.