Tackle the Key Technical Rpoblem for Improving Surface Quality in a 3500 Steckel Mill

by Carl Li

Publisher - Spraying Systems (China) Co., Ltd.

Category - General Novel

The 3500 Steckel Mill produces high-strength ship plate, high class pipeline steel, low-alloy high high-strength plate, high-pressure boiler steel, bridge steel, high quality carbon structural steel, vehicle beam steel and so on. There are 2 descaling spot, one is Hydraulic Scale Breaker (HSB) after furnace; another is finishing descaling in Steckel Mill. Hydraulic Scale Breaker (HSB) after furnace can meet production requirement of most steels. But there is a little scale remain on steel surface after HSB while produce some alloy steel. At the same time, this Mill needs high efficient descaling system to ensure better surface when they develop new products. Or they made a loss in new product production because of low efficient HSB descaling. This mill may add a high pressure pump for enhancing descaling capacity, but it needs the cost of about US $ 1.2 million. The most important thing is that they have no room for adding new pump. So this mill asked for high efficient descaling nozzle and revamping their descaling header. Through calculating and comparison testing in lab, this mill selected PRO descaling nozzles and adjusted descaling header. The PRO nozzles part name is 3025E; the spraying height is adjusted to 120mm. The impact is higher 30% than before, but total flow is the same with before. And total cost is US $ 120,000, just 10% of one new pump cost. We got better result after putting the new header and nozzles into service in Aug. 2010; the surface quality of new product is increased greatly, the removing ratio of first iron scale produced in furnace is more than 99%, the monthly output of new product is raised from 5,000 t to 10,000t。We can come to a conclusion from this case; Steckel Mill and other plate mills can increase descaling capacity just through using latest descaling nozzle and retrofitting header.

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