Vliv parametrů hydraulického odkujení na teplotní ztráty a kvalitu povrchu válcovaného materiálu

Influence of Parameters of Hydraulic Descaling on Temperature Losses and Surface Quality of Rolled Material

journal article - other

en

Hydraulic descaling is a process of removing the oxide from the hot steel surface. Surface quality after descaling is fundamental for the final surface quality of a roll product. Aspect of heat extraction, as a part of descaling process, is not usually seriously considered. Surface sub-cooling can negatively influence the demanded temperature field in the rolled material. The main goal of the paper is to show how the setting of hydraulic descaling parameters can influence heat transfer and the final temperature field in the rolled material. Experimental work was concentrated on the study of descaling in relation to heat transfer and the quality of scale removing from the surface. Two types of measurements were implemented. The first one is a measurement of temperature drop when a product is passing under the nozzle (heat transfer test). The second type is a study of the surface quality where a defined layer of oxides is sprayed and its remaining thickness is evaluated. The heat transfer test is evaluated by inverse task and the results are prepared in a form of boundary conditions suitable for using in the numerical model. The computation done by numerical model of descaling demonstrates the influence of various parameters on the process efficiency. Understanding of the hydraulic descaling mechanism enables the optimization of spraying parameters and its influence on the rolling technology.

Hydraulické odstarňování okují je proces odstraňování okují z horkého povrchu oceli. Kvalita povrchu je po odkujení základem pro finální kvalitu povrchu válcovaného produktu. Chlazení povrchu může negativně ovlivnit teplotní pole válcovaného materiálu. Hlavním cílem tohoto příspěvku je ukázat jak lze zadáním nastavení parametrů hydraulického odkujení ovlivnit přenos tepla a tím i konečné teplotní pole válcovaného materiálu.

Hydraulic descaling is a process of removing the oxide from the hot steel surface. Surface quality after descaling is fundamental for the final surface quality of a roll product. Aspect of heat extraction, as a part of descaling process, is not usually seriously considered. Surface sub-cooling can negatively influence the demanded temperature field in the rolled material. The main goal of the paper is to show how the setting of hydraulic descaling parameters can influence heat transfer and the final temperature field in the rolled material. Experimental work was concentrated on the study of descaling in relation to heat transfer and the quality of scale removing from the surface. Two types of measurements were implemented. The first one is a measurement of temperature drop when a product is passing under the nozzle (heat transfer test). The second type is a study of the surface quality where a defined layer of oxides is sprayed and its remaining thickness is evaluated. The heat transfer test is evaluated by inverse task and the results are prepared in a form of boundary conditions suitable for using in the numerical model. The computation done by numerical model of descaling demonstrates the influence of various parameters on the process efficiency. Understanding of the hydraulic descaling mechanism enables the optimization of spraying parameters and its influence on the rolling technology.

hydraulic descaling, experiment, heat transfer, surface quality, cooling

19.09.2004

GRIPS media GmbH

Německo

1611-4442

Steel Grips, Journal of steel and related materials

2004

2

367–370

4