Annealing process of bell type annealing furnace:
The cold rolling strip annealing process system is mainly determined based on the chemical composition of the steel, the technical standards of the product, the size and coil weight of the strip. The process system must ensure that there is no adhesion between the coils in the production and that the surface does not oxidize.
A. Determination of heating rate The heating rate of steel is mainly determined by the thermal conductivity of the steel. The carbon content and alloy content in steel have a greater effect on heat conduction. If their content is high, the thermal conductivity is small, and the heating speed should be appropriately slower to avoid unevenness in structure and performance caused by excessive internal and external temperature differences. From room temperature to 400 ° C, the heating rate is generally unlimited. According to the principle of the crystallization process, the strip's internal structure does not change significantly from room temperature to 400 ° C. The elongated grains have just recovered during the rolling process and no recrystallization has yet formed. Therefore, the heating rate of the steel in this range The sooner the better. The strip is heated from 400 ° C to the holding temperature. The heating speed has a considerable impact on the performance and surface quality of the strip. Generally, it is recommended that the heating rate be 30 to 50 ° C / h. During the period when the strip is heated from 400 ° C to a temperature below 723 ° C, it is the recrystallization stage. Therefore, the heating rate must be controlled in this temperature range.
B. Determination of holding temperature and holding time The recrystallization temperature of steel is not a fixed temperature. It is related to the internal structure of the strip. The recrystallization temperature in actual production is selected according to the product in the range of 570 ~ 720 ° C. The holding temperature and holding time are mainly determined according to the product standards, technical conditions and the thickness of the steel type and strip. The holding time and temperature are also related to the coil weight and strip thickness. For large coils and thick steel plates, the holding temperature is high and the holding time is also long. For steel and thin gauge strips that are prone to interlayer adhesion defects, the heat preservation temperature can be appropriately lower and the heat preservation time can be shorter.
C. Bright annealing To make the strip steel without decarburization and oxidation, bright annealing must be performed. The key problem of annealed steel coils against oxidation is that the pressure in the protective cover must meet the process requirements. In addition, we must carefully do cold and hot blowing. The purpose of cold blowing and hot blowing is to use protective gas to drive away the air in the inner cover and the oil and gas moisture brought by the Steel Coil. The function of hot blowing is to remove the residual gas in the inner cover, and it is more important to remove all the harmful substances such as oil fume and water vapor produced by the emulsion brought by the coil, so as to avoid staining the surface of the Steel Plate. And reduce the surface quality of the steel plate.
Zhejiang Shangding Industrial Furnace Co., Ltd
The company has always adhered to the business strategy of "R & D as the main body" and the product positioning of "quality as the core". It has developed in the industrial heat treatment industry for 20 years, laid a solid foundation in the industry, and become a well-known domestic production base of non-standard customized heat treatment equipment. The company is also rated as a national high-tech enterprise with a municipal R & D center. In order to better serve our customers, we are flexible to introduce talents from the "national thousand talents plan" and establish contacts with many scientific research institutions. The company's business mainly involves industrial furnace field, environmental protection pyrolysis field, and has a number of core technologies with independent intellectual property rights. At the same time, the company also provides R & D technology transfer and technical R & D support for multiple customers. With high-quality products and good after-sales service, the company has won the trust and praise of many customers at home and abroad.
- Company Name: Zhejiang Shangding Industrial Furnace Co., Ltd
- Representative: Ye Yu Fang
- Product/Service: Heat Treatment Furnace , Hardening Furnace , Annealing Furnace , Electric Furnace , Mechanical Equipment , Tempering Furnace
- Capital (Million US $): 10000000RMB
- Year Established: 2011
- Total Annual Sales Volume (Million US $): US$2.5 Million - US$5 Million
- Export Percentage: 11% - 20%
- Total Annual Purchase Volume (Million US $): US$1 Million - US$2.5 Million
- No. of Production Lines: 3
- No. of R&D Staff: 5 -10 People
- No. of QC Staff: Fewer than 5 People
- OEM Services Provided: yes
- Factory Size (Sq.meters): 10,000-30,000 square meters
- Factory Location: Industrial concentration area of Lincheng Town, Changxing County
- Contact Person: Mr. yehuajian
- Tel: 86--18367270960
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