Segmented precise control type heat treatment process of hot-galvanized strip steels and alloying furnace thereof

Abstract

The invention discloses a segmented precise control type heat treatment process of hot-galvanized strip steels and an alloying furnace thereof. The process comprises the following steps: the heating, the heat insulation and the cooling are sequentially performed for strip steels output from a zinc pot; and finally, the alloying of the strip steels is realized; the key is to oppositely inject air on the two side surfaces of the strip steels, so that a plurality of high-temperature air screens perpendicular to the conveying direction of the strip steels are formed in a middle heat insulation section; and temperature signals in all partition areas of the high-temperature air screens are timely transmitted to a center control PLC (Programmable Logic Controller) processor, so that the center control PLC processor controls the ejection speed of the high-temperature air screens, the temperature of the air screens and the power of resistive heaters in each of the partition areas in real time so as to precisely control the heat insulation temperature in each of the partition areas. The alloying furnace comprises a bottom heating section, the middle heat insulation section and an upper cooling section, wherein sealing air knife generators are respectively arranged in outlets of three partition sections of the middle heat insulation section. The process and the alloying furnace can restrain the generation of the chimney effect, reduce the heat emission of the heat insulation section, and improve the heat treatment efficiency.

Description

technical field [0001] The invention relates to the field of hot-dip galvanized strip steel manufacturing, in particular to a hot-dip galvanized strip steel subsection precision-controlled heat treatment process and an alloying furnace thereof. Background technique [0002] Due to its low production cost, good corrosion resistance, coating performance, welding performance and impact resistance, hot-dip galvanized steel sheet is very suitable for high-end hot-dip galvanized product consumption industries such as automobiles and home appliances, and can meet the needs of users. The quality requirements of high-quality surface characteristics and good internal performance of products. [0003] The hot-dip galvanized steel strip output from the zinc pot usually needs to complete multi-stage heat treatment in the alloying furnace. The internationally accepted process is the annealing process of "first high temperature and then low temperature". There is also a slight difference ...

AI Technical Summary

Problems solved by technology

However, due to the lack of effective separation of the central heat preservation section, the resistance heaters in each section adopt open-loop control and are heated according to the predetermined temperature. The coupling effect of the thermal field between different sections makes it difficult to accurately control the amount of heat released. Abnormalities are prone to occur, and there is great uncertainty in the insulation effect, resulting in fluctuations in alloying properties

Moreover, there is a large heat loss between the movable insulation section and the fixed insulation section, and the outlet temperature of the fixed insulation section is still high due to the "chimney effect", which has a relatively large adverse effect on the equipment in the subsequent upper cooling section, resulting in cooling capacity. Seriously insufficient

Images