Corrosion-resistant steel pipes for sewage use involve an internal cement mortar coating for wear and corrosion resistance. The internally lined cement mortar clad steel pipes, filled with concrete, can absorb a large amount of heat, leading to an uneven temperature distribution in the column cross-section during a fire, thereby increasing the column's耐火 duration and slowing the rate of temperature rise in the steel column. Once the steel column yields, the concrete can bear most of the axial loads, preventing structural collapse. The fire resistance of composite beams also improves as the temperature of the steel beams transfers heat to the concrete through the top flanges, thereby reducing it. Experimental data show that meeting the one-hour fire resistance requirement can save up to 1/3 to 2/3, or even more, of fire retardant paint compared to steel columns, and the more the pipe diameter, the greater the paint savings. Water supply steel pipes are coated with cement mortar on the inner wall using a centrifugal machine or pipe spray machine, primarily to extend the service life of water supply pipelines, protect water quality, and enhance pipeline water conveyance capacity.
Corrosion-resistant steel pipes with mortar coating for sewage treatment, such as those used in municipal engineering projects: suitable for high-rise building water supply, heating network, water supply projects, gas transmission, buried water transmission pipelines, etc. Oil industry: pipeline for oil transmission, chemical industry, dyeing and printing industries for transporting corrosive media. Sewage treatment: sewage discharge pipes, sewage pipes, and bio-pool anti-corrosion engineering. Agriculture: irrigation pipes, deep well pipes, drainage pipes, and other networks with superior corrosion resistance over steel structures, benefiting the fire and fire resistance of steel pipes. When using mortar, it is common to add additives such as foaming agents, waterproofing powder, etc., to improve its workability and viscosity. Mortar mixed with stones in proportion becomes concrete. The strength grade of mortar refers to the value of the overall distribution of compressive strength obtained by standard testing methods on cubic specimens made and cured according to standard methods at 28 days of age. The performance of steel components under external forces can still have a certain impact, such as adverse effects on deformation, stability, and fatigue resistance. 3. Hot-rolled steel products are difficult to control in terms of thickness and width. We are familiar with thermal expansion and contraction; even if the length and thickness meet the standards at the beginning of hot rolling, a certain negative deviation will still occur after cooling. This negative deviation is more pronounced with wider widths and thicker thicknesses.
Corrosion-resistant steel pipes with cement mortar lining for wastewater applications, construction key points due to varying water sources across regions, different investment levels in cement mortar lined pipe water supply projects, high construction requirements for epoxy and high polymer coatings, and the difficulties in initial rust removal and on-site construction, all contribute to increased pipeline construction costs that can be difficult for owners to bear. Currently, in large and medium-sized cities in our country, cement mortar lined pipes are primarily used for pipeline lining to achieve corrosion prevention. The formation of corrosion and rust inside the pipeline walls maintains a long-term good water conveyance condition with a low friction coefficient. The cement mortar lining, relying on its own adhesion and support from the pipe wall, has a uniform and dense structure, being hard and sturdy. If an epoxy resin coating is applied to the mortar surface, the roughness coefficient after water flow can be further reduced. The cement mortar lining is not just a simple physical barrier but also protects the pipeline through the chemical properties of the cement mortar lining. The mortar layer combines with the pipeline, forming a passivated area with a pH value of 12 on the pipe wall surface. After water flow, water permeates through the cement mortar, becoming rich in alkaline components, rendering the water non-corrosive upon reaching the pipe wall.
