Limit-specification IF steel and furnace zone through plate method thereof

Abstract

The invention discloses a limit-specification IF (interstitial-free) steel and a furnace zone through plate method thereof, belonging to the technical field of cold rolled sheet strip annealing. The IF steel comprises the following components in percentage by weight: not more than 0.0015 of C, not more than 0.03 of Si, 0.1-0.14 of Mn, not more than 0.01 of P, not more than 0.01 of S, 0.02-0.045 of Alt, 0.06-0.08 of Ti, not more than 0.004 of N, and the balance of Fe; and the heating zone temperature is 815-825 DEG C, the slow cooling zone temperature is 620-630 DEG C, the fast cooling zone temperature is 340-350 DEG C, and the overaging temperature is 350-360 DEG C. According to the invention, by optimizing furnace zone tension, lowering furnace zone temperature, reducing roller body temperature difference, preventing steel strip from off-tracking and other methods, furnace zone stable through plate of automobile plates with thin wide specification is realized and the annealing plate shape quality is significantly improved.

Description

technical field [0001] The invention belongs to the technical field of cold-rolled strip annealing, and relates to an IF steel with a limit specification and a method for passing the strip in a furnace area. Background technique [0002] IF steel, that is, interstitial atom-free steel, sometimes called ultra-low carbon steel, has excellent deep drawing properties, and now the elongation and r value can reach 50% and more than 2.0, and it has been widely used in the automotive industry. In IF steel, due to the low content of C and N, a certain amount of titanium (Ti), niobium (Nb) and other strong carbon-nitrogen compound forming elements are added to completely fix the carbon, nitrogen and other interstitial atoms in ultra-low carbon steel as Carbonitrides, resulting in clean ferritic steel without interstitial atoms, that is, ultra-low carbon interstitial atom-free steel. [0003] The main thickness range of automobile sheets is 0.7-1.2mm, and the width range is 1400-1800m...

AI Technical Summary

Problems solved by technology

[0003] The main thickness range of automobile sheets is 0.7-1.2mm, and the width range is 1400-1800mm, mainly EDDQ / SEDDQ-IF steel sheets. The main characteristics of automobile sheets are low carbon content (C≤0.002%), with good depth However, the IF steel with thin and wide specifications is prone to high-temperature warping in the furnace, which cannot realize the high-speed, high-efficiency, and high-quality production of the continuous annealing unit. It may eventually lead to a major accident of parking and starting the furnace. It takes about 20 hours to deal with the accident in the furnace area, which not only seriously affects the production rhythm, but also produces a considerable amount of waste products. There is a slight buckling phenomenon at a quarter of the width of the board, and the quality of the board shape cannot meet the needs of customers

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