Total-hydrogen bell type furnace annealing method for cold-rolled strip steel

Abstract

The invention discloses a total-hydrogen bell type furnace annealing method for cold-rolled strip steel. The annealing method comprises the following steps: a, placing to-be-annealed strip steel on a charging furnace base, and cleaning a heated bell, so that the content of the heated bell is no more than 1%; b, placing a cooling bell on the furnace base, and starting air cooling; c, when the furnace temperature is lowered to 270 DEG C, stopping air cooling, and stopping the running of a furnace base fan; d, performing water spraying cooling for ten minutes, then performing low-speed running on the furnace base fan for ten minutes, then performing high-speed running until the hottest spot temperature is lowered to 160 DEG C, and then performing low-speed running on the fan base fan; e, cleaning hydrogen gas again with nitrogen gas until the content of the hydrogen gas is no more than 5%; and f, hoisting out the cooling bell and the inner cover, and hoisting the annealed strip steel out of the furnace. The total hydrogen is adopted as a protective gas for annealing, so that not only can the heat transfer efficiency be significantly improved, and the annealing capability of the bell type furnace can be enhanced, but also the furnace temperature uniformity is improved, the mechanical performance of the strip steel can be guaranteed, and the internal quality and surface quality of cold-rolled plates can be increased.

Description

technical field [0001] The invention relates to the technical field of heat treatment, in particular to a full hydrogen bell furnace annealing method for cold-rolled strip steel. Background technique [0002] After the cold-rolled strip is rolled, due to the lateral deviation of the thickness in the middle and the thinness on both sides, there is a gap between the strip layers, and the gap is filled with air, which makes the radial heat conductivity of the strip poor. Therefore, the cold-rolled strip after rolling Annealing treatment is required. In the existing cold-rolled strip annealing treatment, nitrogen or nitrogen-hydrogen mixed gas protection method is mostly used, but due to the low thermal conductivity of nitrogen, the heat transfer efficiency in the annealing process is correspondingly low, and nitrogen does not have reducing During the annealing process, the surface of the strip steel is prone to oxidation, which has a certain impact on the quality of the strip ...

AI Technical Summary

Problems solved by technology

In the existing cold-rolled strip annealing treatment, nitrogen or nitrogen-hydrogen mixed gas protection method is mostly used, but due to the low thermal conductivity of nitrogen, the heat transfer efficiency in the annealing process is correspondingly low, and nitrogen does not have reducing The surface of the strip steel is prone to oxidation during the annealing process, which has a certain impact on the quality of the strip steel