Tuesday, February 11, 2020

Classification and Development of Direct Rolling and Hot Feeding

The real direct rolling is to roll the continuous casting slab sent from the continuous casting machine directly into the final product without any other heating or heating process. However, for many years, most of the production process research and tests for producing high-quality products have reheated or reheated the continuous casting slab before rolling.

Continuous casting slab hot feeding and hot charging and direct rolling technology are new technologies under development, and the specific characteristics are as follows:

Continuous casting slabs are directly rolled without heating or supplemental heating, referred to as CC-FDR, and are classified into 1 type. Under the condition that the surface temperature is above 820 ° C (the core is above 960 ° C), the continuous casting slab is directly sent to the rolling mill without any form of heating and supplemental heating, and without building a heating furnace. The slab has not undergone the γ-α-γ phase transformation recrystallization process before rolling, and the as-cast coarse austenite grains are still retained. The trace elements Nb and V do not have the precipitation and re-dissolution processes in conventional cold-loading furnaces, so they must be developed. A new rolling process to obtain a grain-refined structure.

Continuous cast slab rolling, referred to as CC-DR, is classified into 2 types. The continuous casting slab is directly sent to the rolling mill through the corner heating device during the conveying process without passing through the heating furnace under the conditions above A3 temperature.

Continuous casting slab hot direct rolling, referred to as CC-HDR, is classified into 3 categories. The continuous slab temperature is above A3. The slab does not pass through the heating furnace. During the conveying process, the rollable temperature is reached by supplementary heating and soaking, and it is directly sent to the rolling mill for rolling.

Continuous hot-rolling of continuous casting slabs, referred to as CC-DHCR, is classified into 4 categories. The continuous casting slab temperature is below A3 and above A1, and the casting slab is directly sent to a heating furnace for heating and rolling. Due to the high temperature of hot charging, it is also called red delivery, and the heating furnace acts as a buffer between the continuous caster and the rolling mill.

Continuous hot-rolling of continuous casting slabs, referred to as CC-DHCR, is classified into 4 categories. The continuous casting slab temperature is below A3 and above A1, and the casting slab is directly sent to a heating furnace for heating and rolling. Due to the high temperature of hot charging, it is also called red delivery, and the heating furnace acts as a buffer between the continuous caster and the rolling mill.

The continuous casting slab cold rolling furnace is heated and rolled, referred to as CC-CCR, and is classified into 6 categories. This is the conventional rolling method when there is no hot-feed and hot-fill process.


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