HEAVILY ANTICORROSIVE CLAD STEEL MATERIAL

摘要

PURPOSE:To enable the corrosion resistance of a clad steel material by providing a band of continuous projection of more than a specific height for the periphery of the covering of a heavily anticorrosive clad steel material. CONSTITUTION:A spiral projection 2 of a height of about 0.3 mm or more is provided for the periphery of a steel tube 1 having a heavily anticorrosive polyethylene covering. Since damage to the tube 1 during driving period can be prevented effectively, the corrosion resistance of the heavily anticorrosive converting can be kept without damage even when it is driven into corrosive ground.