Steel surface should be no visible oil, dirt, scale, rust and paint coating attachments, any markings should be only slight discoloration of dot or stripes.

钢材表面应无可见的油脂、污垢、氧化皮、铁锈和油漆涂层附着物，任何残留痕迹应仅具点状或条纹状的轻微色斑。