Mild steel pipes with ceramic line coating are essentially different from traditional steel pipes, wear-resistant alloy cast steel pipes, cast stone pipes, and steel-plastic and steel pipes.Download PDF
The outer layer of the ceramic steel pipe is a steel pipe, and the inner layer is corundum. The corundum layer has a Vickers hardness of 1100-1500 (Rockwell hardness of 90-98), which is equivalent to tungsten-cobalt hard gold. The wear resistance is 20 times higher than that of the carbon steel pipe, and it is much superior to the corundum wheel which is usually bonded. Now the corundum grinding wheel is still the main grinding wheel for all kinds of grinding machines.
The corundum layer in the ceramic steel tube can wear away the corundum grinding wheel. The wear resistance of ceramic steel pipes is mainly due to the corundum layer with a thickness of several millimeters in the inner layer, and its Mohs hardness is 9, which is second only to diamond and silicon carbide. Its hardness is relatively high among all oxides. Only about 20% of the cast stone components are corundum, most of which are SiO2, and the Mohs hardness of SiO2 is 7.
High chromium or rare earth wear resistant alloy tube, Vickers hardness of about 400 (Rockwell hardness of about 50); less than one third of corundum hardness. Therefore, wear-resistant alloy cast steel pipe, cast stone pipe anti-wear depends on the composition and organization, but also depends on the thickness, ceramic steel pipe anti-wear ability compared with them, has a qualitative leap.
I. Application in metallurgy and electric power industry
Metallurgy, power industry transportation of pulverized coal, ash, mud, limestone paste slurry, such as the annual need to consume a large number of metal pipelines. The use of ceramic composite pipe to replace other pipelines, with high wear-resistant, long life, easy installation and remarkable economic benefits. Shandong Liaocheng Chang-run thermal power plant, Liaocheng China power Plant, Beijing North New building materials group, Henan Hebi Power Plant, Gansu Pingliang Power Plant, Taiyuan Coal preparation plant, Shimen power plant in Hunan, Hebei Jinniu Energy Co., Ltd. Gequan Coal Preparation plant, Xingtai coal preparation plant and other industrial operations, its operating life is more than 10 times times or even dozens of times times more than steel pipe.
II. application in mining and coal industry
(1) Mine: mine filling, concentrate powder and tailings transportation to the pipeline of serious wear, the past use of mineral powder conveying pipelines such as Panzhihua, Daye mine, such as the service life of less than one year, the tube can increase the life expectancy by about 5 times times.
(2) Coal: Coal preparation and long-distance pipeline transportation of coal is commonly used in wet transport, the requirements of the pipe is both wear-resistant and corrosion-resistant, the use of the tube can be used as a long life transport pipe, the economic benefits are considerable.
(1) The tube does not pollute and does not adhere to the molten aluminum solution. It is an ideal material to manufacture molten aluminum equipment, aluminum liquid conveying pipe and liter liquid pipe which are sensitive to iron pollution and need heavy labor for finishing and maintenance after use.
(2) The tube has good abrasion resistance and heat-resisting corrosion. It is suitable for conveying corrosive materials containing solid particles and high temperature corrosive gas and sulfur-containing hot water.
Alumina is a cost effective and widely used material in the family of engineered ceramics. Alumina ceramics have been developed and optimized for maximum wear resistance and corrosion resistance.
|Content of Alumina||≥95%|
|Rockwell Hardness||≥80 HRA|
|Impact Strength||≥850 Mpa|
|Coefficient of Linear Thermal Expansion||20W/m.K|
|Sand injection test||30% Transfer test of sludge with SiO2|
|Ceramic lined Steel pipe||0.0022||Ceramic lined Steel pipe||3|
|Ceramic pipe Al2O397%||0.0025||S45C||25|
|Rockwell Hardness (HRA)||90|
|Thermal Conductivity 20℃||20W/m.k|
|Coefficient of Thermal Expansion||7.2×10-6m/×m.k|
|Young's Modulus 20℃||277GPa|
|Shear Modulus 20℃||113GPa|
|Surface Finish: As Fired||1.27mm|
Wear-resisting bend (wear resistant ceramic pipe)just as its name implies is a relatively traditional is more wear-resisting bend (wear resistant ceramic pipe), adopted the new wear-resistant plastic production, used in large industrial, currently occupies the market share of around 80%.
Self-propagating high temperature synthesis technology of corundum ceramic composite steel pipe is that is, "SHS" technology composite, is a national High-tech "863" project, is the original national metallurgical Industry Department, the Ministry of Electricity Project focused on the promotion of new products, the tube from within to outside by ceramic (corundum) layer, transition layer and steel layer composed of three parts.
Ceramic composite pipe due to corundum ceramic (a-AL2O3), Mohs hardness of 9.0 is equivalent to more than HRC90. Therefore, it has high wear resistance for abrasive media conveyed by industries such as metallurgy, electric power, mining, and coal. It has been confirmed by industrial operation that its wear life is ten times or even several ten times that of hardened steel.
SHS ceramic composite pipe is not like a convex spiral line on the inner surface of a seamless steel pipe because the inner surface is smooth and never corrodes. The inner surface roughness and clear water resistance characteristics of the relevant test units were tested. The smoothness of the inner surface was better than that of any metal pipe. The clear drag coefficient was 0.0193, which was slightly lower than the seamless pipe. Therefore, the tube has the characteristics of small running resistance and can reduce operating costs.
Since the steel ceramic layer is (a-AL2O3), it is a neutral characteristic. Therefore, it is resistant to acid and alkali and seawater corrosion, and it also has anti-scaling properties.
Due to the corundum ceramic (a-AL2O3), it is a single stable crystalline structure. Therefore, the composite pipe can operate normally in the long-term temperature range of -50--700°C. Material linear expansion coefficient of 6-8 × 10-6/0C, about 1/2 of the steel pipe. The material has good thermal stability.
Ceramic composite pipes are light weight and affordable. It is 50% lighter than the cast stone tube with the same inner diameter; it is 20-30% lighter than the wear-resistant alloy tube, and it has good wear resistance and corrosion resistance because of its long service life, thus supporting hanger costs, transportation costs, installation fees, and Reduce operating costs. Comparing the project budget of the design institute and construction unit with the actual project, the project cost is equivalent to the cast stone. Compared with the wear-resistant alloy pipe, the project cost is reduced by about 20%.
Because of its light weight and good welding performance. Therefore, welding, flanges, quick coupling, etc. can be adopted, and the construction and installation are convenient, and the installation cost can be reduced.
Ceramic steel pipe and traditional steel pipe, wear-resistant alloy cast steel pipe, cast stone pipe, as well as steel plastic, steel rubber pipe, etc. have essential differences. The outer layer of ceramic steel pipe is steel, and the inner is corundum. The Vickers hardness of corundum layer is as high as 100-1500 (Rockwell hardness is 90-98), which is equivalent to tungsten cobalt hard gold. The wear resistance is more than 20 times times higher than carbon steel pipe, it is superior to the corundum grinding wheel which is usually bonded. Now the corundum grinding wheel is still the main grinding wheel of the grinding mill. The corundum layer in the ceramic steel tube can wear away the corundum grinding wheel. The abrasion resistance of ceramic steel tube is mainly by the inner layer of several millimeters thick corundum layer, its Morse hardness is 9, second only to diamond and SIC, in all oxides, its hardness is the highest.
The inner liner ceramic wear-resisting steel pipe is made by SHS high temperature synthesis-centrifugal method, the melting point of corundum in ceramic steel pipe is 2045 ℃, the corundum layer and steel layer have special structure and stress field because of the process reason. Under normal temperature, the compressive stress of the ceramic layer, the tensile stress of the steel layer, the two opposites, into a balanced whole. Only when the temperature rises to more than 400 ℃, because the thermal expansion coefficient is different, the new stress field produced by the thermal expansion and the original stress field in the ceramic steel pipe cancel each other, so that both the ceramic layer and the steel layer are in a free equilibrium state. When the temperature rises to 900 ℃ the inner liner ceramic wear-resistant steel pipe into the water, repeatedly soaked repeatedly, the composite layer does not crack or cracking, showing the incomparable thermal shock resistance of ordinary ceramics. This performance is of great use in construction, because the outer layer is steel, in addition to heating the inner layer does not crack, in the construction, the flange, blowing, explosion-proof doors can be welded, but also can be directly welded to connect, which is more than wear-resistant cast stone pipe, wear-resistant cast steel pipe, Rare-earth wear-resistant steel pipe, bimetal composite pipe, steel pipe, Steel rubber pipe In the construction is not easy to weld or welding more than a chip. Internal liner ceramic Wear-resistant steel pipe resistance to mechanical impact is good, in transport, installation beat and the two support between the weight bending deformation, the composite layer does not break off.
At present, the practice of dozens of thermal power plants shows that the wear resistance of the inner-lined ceramic steel tube is high, and the resistance to fluid scouring is strong. In the first air duct, the bending pipe wear the most quickly, the wear resistance of the inner liner ceramic wear-resisting steel pipe is more than 5 times times higher than that of the thick wall wear-resisting cast steel elbow.
In practice, the inner liner ceramic wear-resistant steel pipe after 1-2 years to open observation and measurement, the composite layer has no obvious wear or fall off, in the same size and unit length of the pipeline, the internal liner ceramic wear-resistant steel tube weight only wear-resistant cast steel pipe or bimetal composite pipe of about 1/2, the cost of each of the meters reduced 30–40%, Only cast stone pipe and Rare-earth wear-resistant steel pipe weight of about 2/5, per meter project cost reduction of more than 20%. In the corrosive or high-temperature place to use the liner ceramic wear-resistant steel pipe, its price is only a stainless steel tube, nickel-titanium tube of a fraction of.
Fluid pipeline transportation is not only used in the power industry, but also in metallurgy, coal, petroleum, chemical, building materials, machinery and other industries. When the pipe is transported with large grinding material (such as ash residue, pulverized coal, mineral fine powder, tailings cement, etc., there is a problem of fast abrasion of pipe, especially the bending pipe wear fast; when conveying a strong corrosive gas, liquid or solid in the pipeline, there is a problem that the pipeline is corroded and destroyed quickly. When conveying the material with high temperature in the pipeline, there are some problems such as the price of heat-resisting steel pipe is very expensive. The internal liner ceramic wear-resistant steel pipe market, these problems are solved.
The ceramic lined pipe transport has been widely used in the industries of electric power, metallurgy, coal, petroleum, chemical engineering, building materials, mechanism and so on.
The ceramic lined elbow throughout the power, metallurgy, coal, petroleum, chemical, building materials, machinery and other industries, and high-speed development. When lining the wear-resistant ceramic elbow to deliver high grinding material (such as ash, coal, ore powder, etc.), there is a lining of wear-resistant ceramic elbow wear fast, especially the elbow Wear faster. When lining a The ceramic lined elbow to deliver a highly corrosive gas, liquid or solid, there is a problem that the lined wear-resistant ceramic elbow is corroded and is quickly damaged.
There is a problem that it is expensive to use a heat-resistant steel pipe when the material having a higher temperature is conveyed in the lining of the wear-resistant ceramic elbow. After lining the wear-resistant ceramic elbow, these problems are solved.
The ceramic lined elbow is widely used in wear and tear of the mine filling material, ore powder and tailings transport, coal-fired power plant powder, smelting, ash and other lined with wear-resistant ceramic elbow is also very appropriate.
The ceramic lined pipe, Elbows, Reducer, Tees and others manufactured in our factory have been used in over 200 thermal power plants, more than 50 mines and the industries of coal, building materials, mechanism, petroleum and so on.
The abrasion pipe of thermal power plant is mainly conveying raw coal powder, ash slag, flue gas desulfurization (FGD) limestone powder and slurry, due to the transmission of medium velocity fast, poor operating conditions, resulting in pipelines, especially elbow, variable diameter pipe serious wear and corrosion, not only consumes a lot of metal materials, but also to the thermal power plant security, economic operation has brought hidden dangers. The abrasion mechanism of pipeline is mainly based on erosion wear. Wear-resistant pipe can be divided into two categories: single metal pipe and composite pipe.
Hoop strength is the resistance against radial pressure. The strength of the ceramic -lined steel composite pipe is 300 to 500MPa.
Ceramic liner pipe is a high technology production technology-self-fuel high temperature clutch synthesis method.
Ceramic Liner Composite pipe is a high technology production technology-self-fuel high temperature clutch synthesis method. The tube is composed of corundum ceramics, transition layer and steel three layers respectively from inside to outside, the ceramic layer is formed dense corundum porcelain (Al2O3) at high temperature above 2,200 ℃, and the steel pipe is formed firmly by the transition layer.
1. Good abrasion resistance
Ceramic lined pipe due to the inner lining of corundum ceramic (A-al2o3), the Mo hardness of up to 9.0 of the equivalent HRC90. Therefore, the metallurgical, electric power, mining, coal and other industries to transport the grinding medium has high wear resistance. The industrial operation confirms that its wear-resisting life is 10 times times or even dozens of times times that of quenched steel.
2. Small Operation resistance
corundum ceramic wear-resistant tube in the inner surface of smooth, and never rust, nor like seamless steel tube inside the surface has convex spiral. After testing the internal surface roughness and water resistance characteristics of the testing units, the smoothness of the inner surface is superior to any metal pipe, the resistance coefficient is 0.0193, slightly lower than the seamless pipe.
3, corrosion resistance, anti-scaling
Because the steel ceramic layer is (A-al2o3), it is a neutral trait. Therefore, with acid and alkali resistance and seawater corrosion, and at the same time with anti-scaling and other characteristics.
4. High temperature resistance and heat-resisting performance
The corundum ceramic (A-al2o3) is a single stable crystalline structure. Therefore, the composite pipe can operate in the -50--700℃ temperature range for a long time. Material linear expansion coefficient 6-8x10-6/0c, about 1/2 of steel pipe.
5. Low construction cost
corundum ceramic wear-resistant tube light weight, the price is suitable. The casting pipe with the same inner diameter is lighter than 50% and lighter than that of the wear-resistant alloy tube 20–30%.
6. Convenient installation and construction
Because of the light weight of the tube, and good welding performance. Therefore, welding, flange, rapid connection and so on, construction and installation is convenient.
7. Ceramic lined pipe with the traditional steel pipe, wear-resistant alloy cast steel pipe, cast stone pipe as well as steel plastic, steel rubber pipe, etc. have essential differences. The outer layer of ceramic steel pipe is steel, and the inner is corundum. The Vickers hardness of corundum layer is as high as 100-1500 (Rockwell hardness is 90-98), which is equivalent to tungsten cobalt hard gold. The wear resistance is more than 20 times times higher than carbon steel pipe, it is superior to the corundum grinding wheel which is usually bonded.
Now the corundum grinding wheel is still the main grinding wheel of the grinding mill. The corundum layer in the ceramic steel tube can wear away the corundum grinding wheel. The abrasion resistance of ceramic steel tube is mainly by the inner layer of several millimeters thick corundum layer, its Morse hardness is 9, second only to diamond and SIC, in all oxides, its hardness is the highest.
There are probably hundreds of different methods for packing a abrasion resistant pipe and Elbows, and most of them have merit, but there are two principles that are vital for any method to work prevent rusting and Sea transportation security.
Wear-resistant ceramic composite pipe, full name ceramic liner composite steel pipe, is a kind of ceramic composite steel pipe.
Ceramic (Corundum: a-Al2O3) lined abrasion resistant straight pipe and fittings are lined with highly abrasion resistant ceramic by SHS -------Self-propagating High-temperature Synthetic process.
A small amount of iron also remains in the ceramic layer. There is a thin equiaxed grain area of alumina near the steel pipe wall, and then alumina was grown in form of dentrite to the surface of ceramic layer.
When abrasive material is transported through steel pipe in mining applications, typically as pumped slurry, the pipe can quickly be eroded from the inside out, which in more extreme cases can result in pipe leaks and even failure, or significant maintenance costs and downtime for pipe replacement.
Section of the composite pipe
FeAl2O4 distributes among alumina dentrite. Although the ceramic layer was solidified from one end to another end of a pipe, the microstructure of ceramic layer was almost uniform throughout the whole length of the pipe.
Resistance to thermal shock
Hoop strength is the resistance against radial pressure. The strength of the ceramic -lined steel composite pipe is 300 to 500MPa.
Compression-shear strength is the bonding strength at the interface between the ceramic layer and the steel pipe. The compression-shear strength of the ceramic-lined composite pipe is 15 to 20MPa.
Resistance to mechanical shock
The ceramic layer does not crack or flake off when the composite pipe receives a mechanical shock.
Resistance to thermal shock
The ceramic layer does not crack or flake off when heated to 800℃ and then quenched.
Resistance to abrasion
The ceramic-lined steel composite pipe has exceptional resistance to abrasion. Its service life in materials transportation with hard abrasives is more than 20 times longer than in common steel pipe.
For these abrasive applications, mild steel pipe is not tough enough to stand up to the abuse for more than a year or two. As a result, maintenance engineers are seeking superior piping alternatives to reduce maintenance and prolong system life, at a price point that will not significantly impact the budget.
The general servicelife of common steel elbow is about 700 hours.
The ceramic-lined steel composite pipe can be joined by welding the steel pipe layer.
The ceramic-lined steel composite pipes are lighter than alloy pipes, cast iron pipes, and cast stone pipes, which reduces the expense of transportation and makes the pipes easier to install.
Good weld ability
The ceramic-lined steel composite pipes can be easily connected by welding, or with flanges and soft easy connectors.
The composite pipes have good corrosion-resistant. There is no evidence of corrosion filling the composite pipes with bitter for one year (left), but the common steel pipe under the same condition is corroded seriously (right).
Ceramic liner composite pipe is different from traditional seamless steel pipe, wear-resisting alloy cast steel pipe, cast stone pipe, steel plastic pipe and steel rubber pipe.
Self-propagating high temperature synthesis (SHS) is used to describe a process in which the initial reagents (usually powders), when ignited, spontaneously transform into products due to the exothermitic heat of reaction.
A well-known example of SHS reaction is the thermite reaction given below:
This reaction generates temperatures above the melting point of alumina and is used in the thermit welding process for joining railway lines.
Several other terminologies - such as combustion synthesis, gasless combustion or self-propagating exothermic reaction - are used to describe the process.
The types of material that can be formed using this process include metal borides, silicides, carbides, nitrides, sulphides, aluminides and oxides.
The combination of high rigidity of ceramic and high elasticity of steel gives the pipe unmatchable features as an abrasion resistant, heat resistant and corrosion resistant material for use in the fields of power generation, metallurgy, mining, and chemical industry etc.. It has many advantages over steel pipes, cast stone pipes, and steel-plastic compound pipes.
The composite pipe is composed of three layers: ceramic, intermediate, and steel layers. The ceramic layer is formed by molten alumina at a temperature above 2500 degree.
The molten alumina produced from the reaction Fe2O3+2Al=2Fe+Al2O3 spreads on the inside wall of the steel pipe under the influence of a centrifugal force, then solidifies, so the ceramic layer has high density and smooth surface and bonds to the steel pipe. They are widely used to convey highly abrasive material such as fly ash and any other fine powder material in mine, thermo power generating, coal processing plant, metallurgy, construction, etc. The service life is 10 to 20 times longer than normal steel pipe.