熱捲箱製程對熱軋產率之影響及改善研究

Effect and Improvement of the Coilbox Process on the Hot-Roll Product Yield

熱軋鋼捲之生產有一貫軋延及熱捲箱兩種製程，加熱爐之燃料則以煉焦爐氣（COG）或重油為主。甲鋼鐵公司之熱軋鋼捲生產採用燒重油之加熱爐配合熱捲箱製程，其熱軋鋼捲產品產率較乙鋼廠差，而後者乃採用COG加熱爐配合一貫軋延製程。本研究之目的在釐清前述問題是否與產線差異有關以及如何改善。本研究分成三階段進行，第一階段先澄清前述問題的主因不在加熱爐的差異。第二階段確認熱捲箱製程會因為盤捲而造成氧化皮大量脫落，露出新鮮表面，於高溫再迅速氧化而提高銹損，進而導致產率降低。第三階段乃於現有熱捲箱作業下，以適當之盤捲條件，獲得不損表面品質但仍可提升產率之適當製程。

Continuous rolling processes and coilbox processes are both used in the production of hot-roll bands. The coke oven gas (COG) and oil are two major fuels for hot-rolling furnaces. An oil furnace with the coilbox process was used by company A, but a COG furnace with the continuous rolling process was adopted by company B. The yield of hot-roll bands at company A was less than that at company B. This work was aimed at clarifying the cause of the less yield and then improving it. There were three major findings. The first one was that the oil furnace of company A was not responsible for the less yield. The second one was that the less yield was actually related to the coilbox process because a repetitive exfoliation and surface oxidation during the coilbox coiling generated more scales and caused significant material losses. The third finding was a suitable coiling speed to reduce the scale exfoliation and to increase the yield, without degrading the surface quality.