Self-propagating High-temperature Synthetic process

Self-propagating high-temperature synthesis (SHS) and processes based on SHS are currently being developed the world over for the production of powders and near-net shape components of advanced materials.

The ceramic layer is formed by molten alumina at a temperature above 2500 degree Celsius. 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.
Main Properties of
Sand injection test 30% Transfer test of sludge with SiO2
Material Volume diminution
(cm3)
Material Volume diminution
(cm3)
Ceamic lining
Steel pipe
0.0022 Ceamic lining
Steel pipe
3
Ceramic pipe
Al2O397%
0.0025 S45C 25

The combination of high rigidity of ceramic and high elasticity of steel gives the pipe unmatchable features as an 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.
1. Ceramic Lined Steel Pipe and Elbows:
1.1 The Manufacturing Process of Ceramic Lined Steel Pipe and Elbows:
Ceramic (Corundum: a-Al2O3) lined abrasion resistant straight pipe and are lined with highly abrasion resistant ceramic by SHS ——-Self-propagating High-temperature Synthetic process.
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.
1.2. Features and Advantages:
a). High Abrasion Resistant:
Vickers hardness of the corundum lining is HV1100 to1500, as high as that of tungsten-cobalt hard alloys, and the abrasion resistance is 20 times as carbon steel pipes. A composite elbow was used in a mining plant for about fifty thousands hours.
The general service life of common steel elbow is about 700 hours.
b). Corrosion Resistant:
Corundum is a neutral material, and is acid-proof and fouling -free.
c). Heat Resistant:
Ceramic-lined composite steel pipe can work under circumstances of -50 to 800 degrees Celsius.
d). Lower Weight and Convenient Installation:
The ceramic-lined steel composite pipes are lighter than alloy pipes, cast iron pipes, and cast stone pipes and can be welded or connected through , which reduces the expense of transportation and makes the pipes easier to install.
For the pipes with the same sizes, types and length, the weight of ceramic pipe is about 1/2 of the wearable cast alloy steel pipe’s, while the cost has reduced 10%~20% per meter. The weight of ceramic lined steel pipe is about 1/3 of the cast stone bent pipe’s, 1/2 of the cast stone straight pipe’s.
e). Lower Cost:
Ceramic-lined composite steel pipe can take place of expensive stainless steel, titanium, nickel, cast stone or alloy pipes. Extended service life can also reduce maintenance cost.
1.3.Features of
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. A high density, diamond like hardness, fine grain structure and superior mechanical strength are the unique properties that make it the material of choice for a wide range of demanding applications. Ceramic has uses similar to Cast Basalt but it has greater resistance to wear in high velocity applications and impact resistance in extreme dynamic Systems
耐磨陶瓷复合管的种类有哪些?
耐磨陶瓷复合管的种类有离心浇铸复合陶瓷管道、贴片耐磨陶瓷管道、一体成型耐磨陶瓷管道、全称陶瓷内衬复合钢管,这几种耐磨陶瓷复合管的具体介绍如下:
1、离心浇铸复合陶瓷管道
离心浇铸复合陶瓷管道是采用“自蔓燃高温合成-高速离心技术”制造的复合管材,在高温高速下形成均匀、致密且表面光滑的陶瓷层及过渡层。因为制作工艺简单,成本较低,适合长距离输送粉体采用,但是其耐磨性比耐磨陶瓷管道稍差,一般用作直管。
2、贴片耐磨陶瓷管道
贴片耐磨陶瓷管道是用耐高温强力粘胶将氧化铝陶瓷片粘贴在管道内壁,经加温固化后形成牢固防磨层。该种产品制作工艺相对简单,制作周期短,成本相对较低。
技术规格: 精城拥有各种型号的贴片耐磨陶瓷管道,也可以根据客户需要定制生产。贴片耐磨陶瓷管道基本上不受管道大小限制,直径从1寸到120寸,甚至更大都可以生产。
3、一体成型耐磨陶瓷管道
一体成型是将陶瓷管件整体烧制后,用特制填充料将其浇筑在钢管内部组装而成。该管道内壁光滑、密封性密封性好,具有良好的耐磨、耐腐蚀性能。但是该种产品制作周期长、成本高。
Application of Ceramic lined pipe:
replace cabon steel ,stainless steel and SDR, high wear material discharge. 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).
  • Coal Slurry
  • Incinerated Waste
  • Slurry Disposal System
  • Ore Separation System
  • Sand/Grit Blast Return Lines
  • Bottom Ash Handling System
  • Pneumatic Conveying System
  • Power Plant Scrubber System

Advantages of Ceramic lined pipe:
Vickers hardness of the corundum lining is HV1100 to1500, as high as that of tungsten-cobalt hard alloys, and the abrasion resistance is 20 times as carbon steel pipes.
  1. Heat-resistance, -50 -800 degrees
  2. Easy Installation and Anti-Scaling
  3. Abrasion-Resistance and hardness, is above 9.0
  4. Corrosion-Resistance, 10 times of stainless steel pipe
  5. Economical Cost, 20-30% lower than that of anti-abrasion
How to packing Self-propagating High-temperature Synthetic process:
Packed in Bundle by Steel Strip.
Ex-works length: less than or equal to 3m. Customized maximum length can be achieved by welding.
Other Specifications of the elbow, tee, cross and fittings can be produced according the user.
Delivery Time
According to Your Requirement ASAP
自蔓延高温合成技术
自蔓延高温合成技术(self-propagating high-temperaturesyctthesis f 5f}5] technology)又称燃烧合成技术。依靠化学反应合身放热来制备材料的新技术。
即外加能源(电热或激光等)触发点火剂燃烧,进而引发反应物料(气相一固相,固相-固相、液和一同相等)自发高速反应、放出热髦,反应由局部以燃烧波的形式自动蔓延整个体系,最后获得新的合成材料的技术。反应物可以是元素粉末相互直接棍合或元素粉末与气体,也可用金属氧化物和还原剂及非金属粉末的混合物反应生成热能维持反应持续进行、反应产物必须是稳定的化合物、.该技术具有产物纯度高、设备简单、能耗低‘生产灵活等优点,缺点是工艺参数控制要求较严。已用此法制备出数百种化合物,像各种金属的氮化物、碳化物、硼化物、硅化物、氧化物、氢化物等。S}-IS技术已发展成SH5制粉技术、SHS烧结技术、5H5致密化技术、5HS熔铸技术、5H5焊接技术、SHS涂层技术等。
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2 thoughts on “Self-propagating High-temperature Synthetic process”

  1. SHS烧结可采用以下3种方式进行:
    (1)在空气中燃烧合成;
    (2)将经过预先热处理的混合粉末放在真空反应器内进行合成;
    (3)在充有反应气体的高压反应容器内进行合成。 前面提到普通的SHS技术适用于获得疏松多孔的材料或粉末,为了进一步提高材料的密实度,发展了多种自蔓延高温合成材料的合成与致密化同时进行的一体化技术。
    常用的SHS致密化技术可归纳为3类:
    液相致密化技术、SHS粉末烧结致密化技术、SHS结合压力致密化技术。 SHS焊接是利用SHS反应的放热及其产物来焊接的技术。应用燃烧合成技术,将压制成形的粉末置于被焊材料之间,利用粉末体燃烧合成的高温反应热及合成产物作为填充材料,在压力作用下实现被焊材料之间的连接。加压的目的是为了获得致密性高的焊接接头。
    SHS焊接有三个过程:点火、加压、保温。

  2. 数学模型是理解影响SHS过程基本机理的重要工具,对决定最佳的燃烧条件,控制燃烧过程也有很大帮助。根据能量守恒定律和把反应介质看作连续均匀、各向同性,温度分布连续、均匀,以及物理K、ρ、Cp为常数,即可得到一维有热源的Fourier热传导方程。

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