1. The surface of ductile iron manhole is covered with dust
Steel castings are usually cast in dusty places, where there is a lot of dust in the air, which constantly falls on the surface of the equipment。 They can be removed with water or an alkaline solution。 However, sticky dirt requires high pressure water or steam to remove。
2. Floating iron powder or embedded iron on the surface of nodular cast iron
Free iron will rust and corrode stainless steel on any surface. Therefore, it must be removed. Floating powder can generally be removed by dust. Some have strong adhesion and must be treated with embedded iron. In addition to dust, sources of iron on the surface include the use of ordinary carbon wire brushes for cleaning and sand, glass beads or other abrasive peening for carbon steel, low alloy steel, iron castings, or abrasive stainless steel products previously mentioned for nearby stainless steel parts and equipment. There is no stainless steel protection measures for the material or suspension. During the processing, the wire rope, sling and iron bar are easy to be embedded in or contaminate the surface.
3。 Scratches on the hole cover of nodular cast iron
Scratches and other rough surfaces must be mechanically cleaned to prevent the accumulation of process oil or product or dirt。
4. Rust spots on ductile iron manhole cover
Corrosion of stainless steel products or equipment sometimes occurs before or during processing, which indicates that its surface is seriously polluted. Rust must be removed before the equipment is put into use. The cleaned surface shall be tested for iron and / or water.
5. Rough grinding
Grinding and machining produce rough surfaces, grooves, laps, and burrs. Each defect may cause a certain degree of damage to the metal surface, so that it can not be removed by pickling, electropolishing or shot peening. Rough surface may be the source of corrosion and deposition products. It is not allowed to use rough grinding to clean weld defects or remove redundant weld reinforcement before re welding. In the latter case, the fine abrasive should be used again.
The above is a detailed introduction to the cleaning methods of Shandong ductile iron manhole covers. For more information, please click http://www.kpp647.com