SK85鋼胚熱軋斷裂成因與機械燒除研究

Broken Mechanism of SK85 Slab during Hot Rolling and the Relevant Study on Machine Scarfing Process

陳明宏(M.H. Chen) ； 林冠儒(K.J. Lin) ； 楊清潮(C.C. Yang) ； 黃凱亮(K.L. Huang)

《鑛冶：中國鑛冶工程學會會刊》 52卷3期 (2008/09) Pp. 107-112

https://doi.org/10.30069/MM.200809_52(3).0010

摘要

JIS SK85（SK5）高碳工具鋼為中鋼公司新開發之高品級產品，生產初期曾發生熱軋鋼胚斷裂事故，嚴重影響生產。經製程追蹤調查發現，鋼胚精整過程中之機械燒除作業導致鋼胚表面開裂為事件的主因。研究顯示，SK85鋼胚經機械燒除後，表層因材料特性生成硬脆的麻田散鐵相，加上熱震後的應力作用導致嚴重的延遲性裂紋，最後造成軋斷。利用數值分析發現，鋼胚溫度高於200℃以上的燒除作業可避免麻田散鐵層生成並同時減緩熱震衝擊。

關鍵字

SK85 ； 高碳鋼 ； 熱軋斷裂 ； 斷胚 ； 機械燒除 ； 熱震

並列摘要

JIS SK85 steel is a newly-developed high-grade product in China Steel. In the early stage of production development, slab hot rolling failures often occurred that seriously delayed the production. After detailed production process reviews, it was found that the slabs failures often occurred after machine scarfing that induced the time-delayed cracks on the slab. A further study revealed that the time-delayed cracks were caused by the hard, brittle martensite layer in the slab surface and the stress induced by the hot shock after machine scarfing. A numerical simulation showed that machine scarfing operating at the slab temperature higher than 200℃ can avoid the formation of martensite layer and lower the impact of hot shock.

並列關鍵字

SK85 ； High-carbon steel ； Slab broke ； Machine scarfing ； Thermal shock