论文部分内容阅读
塔干罗格冶金厂使用直径365—385mm、长1000—1600mm、重1380kg的钢锭在114-168mm周期轧机上生产钻杆。这种钢锭采用下注法浇铸成上小下大直通形不带保温帽的钢锭,其头部以高岭土棉垫片保温,在绝热渣保护下浇铸。这样就获得没有缩孔的致密钢锭。虽然钢锭的收缩疏松、裂纹(热裂及冷裂)、皮下气泡处的低倍组织获得改善,但有些钢管仍出现外折及内折缺陷。对缺陷附近区域作金相分析表明,钢锭的裂纹、气泡、收缩疏松、非金属夹杂物等缺陷是造成钢管折迭缺陷的主要原因。
The Taqnagar plant uses rods of 365-385mm in diameter, 1000-1600mm in length and 1380kg in weight to produce drill stems on a 114-168mm mill. This kind of steel ingot is cast by casting method into a steel ingot without a thermal cap on a small, large and straight through shape. The head of the steel ingot is warmed with kaolin cotton pad and cast under the protection of adiabatic slag. This results in a dense steel ingot without shrinkage cavities. Although the ingot shrinkage loose, cracks (hot cracking and cold cracking), under the sub-bubble at low magnification organization to improve, but some still appear outside the pipe and folding defects. Metallographic analysis of the vicinity of the defect shows that defects such as cracks, bubbles, shrinkage and non-metallic inclusions in the ingot are the main causes of the folding defects of the steel pipe.