Vývoj chladicího systému pro novou válcovací trať tlustých plechů

Development of accelerated cooling for new plate mill

článek v časopise - ostatní, Jost

en

The aim of the paper is to design the new wide plate mill. The work on the new cooling technology was supported by extensive laboratory testing while a simulator with full scale testing of cooling units was used. The principal objective of the investigation was to establish the design specification of equipment for accelerated cooling, particularly with respect to the product dimensions and steel grades. The possibilities of accelerated cooling are limited by technical parameters of cooling equipment such as thickness of water layer, flowrate, spray height, position of cooled surface to the nozzles and water or plate speed. These parameters were studied for different product temperatures and water impingement densities from 50 to 110 l s21 m22. The heat transfer coefficient was determined and compared for each case. There were three recognised significant cooling regions: water layer region, impinging jet region without water layer and impinging region with water layer, which must be taken into account. The pplication of the new cooling technology showed better flatness product and productivity higher than previous accelerated cooling system, even shorter cooling length. The rejection ratio by flatness problem ofnew mill was nearly half of the previous one.

V článku je popsán vývoj chladicího systému pro novou válcovací trať pro plechy. Práce na vývoji chladicího systému byly z velké části založeny na laboratorní práci. Cílem bylo nalezení chlazení a vývoj chladicího systému, který by splňoval požadavky na intenzivní chlazení s ohledem na rozměry vývalků a jakost válcovaného materiálu. Možnosti chlazení jsou limitovány zejména tloušťkou vodní vrstvy na povrchu, průtokem chladiva, výškou trysek nad povrchem, orientací povrchu a rychlostí pohybu válcovaného materiálu. Použití nové technologie přineslo lepší rovinnost chlazeného vývalku a vyšší produktivitu než bylo dosaženo na starších tratích. Bylo dosaženo i úspory délky chladicí sekce. Množství výrobků mimo požadované parametry se snížilo na polovinu ve srovnání s předchozím chladicím systémem

The aim of the paper is to design the new wide plate mill. The work on the new cooling technology was supported by extensive laboratory testing while a simulator with full scale testing of cooling units was used. The principal objective of the investigation was to establish the design specification of equipment for accelerated cooling, particularly with respect to the product dimensions and steel grades. The possibilities of accelerated cooling are limited by technical parameters of cooling equipment such as thickness of water layer, flowrate, spray height, position of cooled surface to the nozzles and water or plate speed. These parameters were studied for different product temperatures and water impingement densities from 50 to 110 l s21 m22. The heat transfer coefficient was determined and compared for each case. There were three recognised significant cooling regions: water layer region, impinging jet region without water layer and impinging region with water layer, which must be taken into account. The pplication of the new cooling technology showed better flatness product and productivity higher than previous accelerated cooling system, even shorter cooling length. The rejection ratio by flatness problem ofnew mill was nearly half of the previous one.

Intenzivní chlazení, plechotrať, nová technologie chlazení, chlazení tryskami, součinitel přestupu tepla, experimenty

Accelerated cooling, Plate mill, New cooling technology, Spray cooling, Heat transfer coefficient, Experimental

2013

14.11.2013

Maney Publishing

Spojené království Velké Británie a Severního Irska

0301-9233

40

8

598–604

7