Effect of rolling time and rhythm on steel quality

Kata kunci：rolling, rolls

Keterangan: This paper proposes that the rolling rhythm is the main factor determining the output of the rolling mill. Under certain conditions, the longer the total duration of rolling, the greater the temperature drop of the rolled piece after rolling, which will have a certain impact on product quality, roll pass wear and energy consumption.

The rolling mill work chart represents and reflects the relationship between rolling passes and time. The rolling time, gap time, rolling rhythm and the total duration of rolling marked in various types of rolling charts are called the characteristic time of the rolling chart. Different forms of rolling mill layout and rolling methods lead to different forms of rolling charts, that is, the changing laws of the four characteristic times reflecting the rolling process are different.

Rolling time

That is, the pure rolling time of the rolled piece is a period of time from the biting of the rolled piece to the throwing out of the rolled piece, which can be measured or calculated by the following formula:

T rolling=L/v (where L-rolled piece length, m; v-rolling speed, m/s.)

v=3.14159*D*n/60 (In the formula, D-the diameter of the work roll of the roll pass, mm; n-the number of revolutions of the roll per minute.)

Gap time

It refers to the time interval between adjacent passes in the rolling process, that is, the time from the throwing of the previous rolling piece to the biting of the next rolling piece. For section steel mills, the gap time varies with specific conditions such as mill layout and rolling method.

Rolling cycle

It refers to the time required for each unit to roll a piece of steel, that is, the time interval between the unit rolling the first steel and the second steel. The length of the rolling rhythm is very important, and it is the main factor that determines the output of the rolling mill.

Total duration of rolling

The total time used to roll a piece of steel, some are called the rolling cycle (such as the blooming mill, etc.), and some are called the total duration of rolling. Its meaning refers to the time interval from when the rolled piece is bitten by the first pass to when the rolled piece is thrown out by the last pass. Usually it includes the rolling time of each pass in the rolling process and the gap time between each pass, as well as the gap time between two adjacent steels. The length of the total duration of rolling has a great influence on the temperature reduction of the rolled piece. Under certain conditions, the longer the total duration of rolling, the greater the temperature drop of the rolled piece after rolling, which will have a certain impact on product quality, roll pass wear and energy consumption.