摘  要：針對某鋼廠生產的20#鋼管在穿孔過程中出現表面外折缺陷的質量問題，利用金相顯微鏡、掃描電鏡及能譜儀對穿孔樣品表面缺陷與連鑄坯表面缺陷進行系統分析。通過對大量實驗數據進行比較研究，得到表面缺陷的形態、分布及化學成分，并結合生產工藝分析外折缺陷產生的原因：連鑄坯表面存在縱裂紋缺陷是導致穿孔管表面出現外折缺陷的主要原因。最后，結合該鋼種的連鑄生產工藝提出具體的改進建議。
關鍵詞：20#鋼；外折缺陷；連鑄坯；縱裂紋；改進對策
中圖分類號：TG335.71；TG806；TM930.12；TG356.2+1    文獻標志碼：A    文章編號：1674-5124（2013）05-0028-03
Causes and solutions of outer fold on surface of 20# steel pipes
ZHANG Ke， WU Yuan-yuan， DONG Deng-chao
（Research Institute of Iron and Steel （Sha-Steel） of Jiangsu Province，Zhangjiagang 215625，China）
Abstract: Defects of outer fold were found in cone-roll piercing of 20 steel pipes， which greatly affect the product quality. The surface defects of pierced samples and continuous casting billets were investigated by optical microscope， SEM and EDS. Morphology， distribution and composition were obtained after comparing and analyzing large number of experimental data. Furthermore， the cause was deduced according to the actual production. The results showed that the outer fold on the surface was mainly caused by the longitudinal crack defect on the surface of continuous casting billet. Correspondingly， solutions and suggestions for improvement were proposed in terms of the continuous casting process of this steel.
Key words: 20# steel； outer fold； continuous casting billet； longitudinal crack； solution