大直径圆波浪钢锭的研制与开发

R and D of Large-sized Corrugated Round Steel Ingot

根据大直径、厚壁及超长无缝钢管的市场需要,开发出适用于斜轧穿孔+周期轧管方式的一次成材轧管用大直径圆波浪钢锭。该钢锭采用了波峰小、波谷凹入深度浅、边数多、接近于圆形的断面,锭模内腔小正锥度大高宽比等特殊设计;生产时采取低模体温度、低钢水过热度、低浇注速度及钢锭长时间缓冷等措施,解决了此类钢锭易产生表面裂纹的难题。生产的钢锭内部组织致密、化学成分偏差小,成品管组织均匀、成材率高、成本低。

To meet the need by the market for large-sized, extra-long, heavy wall seamless steel tubes, the large-sized corrugated round steel ingot is developed for the purpose of producing large-sized seamless steel tubes with the rotary-piercing＋pilger mill rolling process, a kind of direct formation technology. The ingot as designed features small wave crest and shallow wave trough, multiple edges, nearly-circular cross-section and small inner taper, etc. Moreover, for the manufacturing, certain technical measures have been taken, including low mould temperature, low hot metal over-heat degree, low cast speed and long retarded ingot-cooling time, etc. As a result, the chronic big problem of the ingot as being apt to develop surface cracking is tackled. The ingot as produced with the above said modification actions has been in possession of such advantages as compact microstructure, and small chemical composition deviation. And therefore, production manufacture of finished pipes with such ingots features uniform pipe structure, high yield and high cost-effectiveness.