What are the requirements for the outer pipe in the production of lined stainless steel clad steel p

In the ordinary galvanized steel pipe is conformed to a thin stainless steel pipe.

The title is unclear, the large-diameter pipe can be rolled with stainless steel composite plate, and the design is based on the use conditions and standards.

Production requirements for lined stainless steel composite steel pipes: stainless steel strips must be fully annealed; The width of the welded steel strip of stainless steel pipe must be over-welded;

When the stainless steel pipe is welded, it must be protected by internal and external gas, and the smooth surface of the steel must be inside; The pipe can be used in cold water, hot water and fire water supply systems.

External pipe requirements: to be able to withstand the external conditions of the water supply system, to be able to choose the connection mode according to the engineering situation. Such as welding, flanging, threading and groove connections.

To meet welding, flange, thread and groove connection requirements, and standards. At the same time, you can refer to the design points of carbon steel pipes and thin-walled stainless steel pipes.

Reference standards: 1), product standard "Code for Design of Building Water Supply and Drainage" GB 50015-2003 "Lined Stainless Steel Composite Steel Pipe" CJ T 192-2004 "Safety Evaluation Standard for Drinking Water Transmission and Distribution Equipment and Protective Materials" GB T 17219-1998 2), Engineering Standard "Code for Construction Quality Acceptance of Building Water Supply and Drainage and Heating Engineering" GB50242-2002

The outer pipe lined with stainless steel composite steel pipe is divided into: galvanized pipe, welded pipe, and seamless pipe. "Special Lined Stainless Steel Composite Steel Pipe Galvanized Steel Pipe".

In recent years, steel composite steel pipe has received more and more recognition from users, and the application range is becoming more and more extensive, but there are still many people who contact this pipe for the first time, and have doubts about the reliability and safety of its connection.

First of all, the first connection method of lining stainless steel composite steel pipe is threaded connection.

Hungry with galvanized pipes.

The connection method of the material is the same, and this method is generally used for those below DN80 caliber.

The second is a trench connection.

It is also the same as galvanized pipes, and generally DN80 caliber upwards are connected in this way.

The third is welding, which is generally in the medium and high pressure pipelines or buried pipelines, or other places with high technical and technical requirements, which is also the safest and most reliable connection method at present. However, this method is more expensive than the first two.

Customers who use stainless steel clad steel pipes lined with stainless steel must choose the connection method suitable for their working conditions, so as to meet the use conditions and not increase unnecessary costs.

Answer: One Advantages:

The stainless steel composite pipe lined with thin-walled stainless steel pipe is a composite thin-walled stainless steel pipe on the inner wall of the steel pipe, which overcomes the defects of easy corrosion of galvanized steel pipe and easy water leakage and aging of plastic pipe connected by hot melt, and is an ideal product for the upgrading of steel pipe for gas transmission, water transmission and oil transportation.

No scaling, no nodulation, corrosion resistance: a very thin chromium oxide film is formed on the inner wall of the pipeline during use, which prevents the metal from continuing to oxidize, so stainless steel has strong corrosion resistance, which can not only withstand the corrosion of water and air, but also the corrosion of weak acid and alkali.

It is resistant to high temperatures, and can convey hot water, boiling water, and steam.

The inner wall is smooth and the fluid flow resistance is small: the lined stainless steel pipe in the lined stainless steel composite steel pipe is welded by cold-rolled stainless steel strip, and the surface of the cold-rolled stainless steel strip is smooth and smooth, so the inner wall of the stainless steel pipe is smooth, the fluid resistance in the pipe is small, there is no scaling, and the fluid is pollution-free.

Can be welded: between the lined stainless steel composite steel pipe can be welded, before welding should use mechanical methods and organic solvents to remove the weld surface and welding groove on both sides of at least 20mm range of oil, rust, metal shavings, oxide film and other dirt.

Can be threaded: the pipe threaded connection surface is a thread with a tooth cross, the tolerance generated during machining will disappear during the thread tightening process, and the huge tightening force ensures that there is no leakage after tightening between the pipe body and the pipe fittings.

The contact surface of the pipe threaded connection is a contact between steel and stainless steel, and the expansion coefficient is very close during thermal expansion and cold contraction.

Good hygienic performance: Because the stainless steel pipe is not corroded by the fluid during use, and the stainless steel pipe body has no impurities into the fluid, the stainless steel composite steel pipe lined with stainless steel can replace the pure stainless steel pipe to transport drinking water.

**Low,

Answer: Lined with stainless steel clad steel pipe before composite:

What are the basic requirements for stainless steel pipes, the basic state of metallurgy, and the surface treatment status?

Lined with stainless steel composite steel pipe composite:

What are the basic metallurgical changes and surface changes of stainless steel pipes?

Lined with stainless steel clad steel pipe after composite.

How to deal with stainless steel pipes from the perspective of basic theory of metallurgy and heat treatment technology?

1. Main control parameters: The main control parameters of the stainless steel composite steel pipe lined with stainless steel are nominal diameter, flattening performance, strength performance, health performance, etc.

2. Definition: Carbon steel pipe is used as the base pipe, and the stainless steel liner pipe is compounded with the base pipe by the diameter reduction method, cold expansion method, deflagration method or brazing composite process.

3. Classification: The connection methods of pipelines are divided into: welded connection, threaded connection, flange connection, and groove connection.

4. Key points of selection: 1) The pipe can be applied to water supply systems such as cold water, hot water and fire water supply. 2) Select the connection mode according to the project situation.

There are welded, flanged, threaded and grooved connections. 3) You can refer to the design points of carbon steel pipe and thin-walled stainless steel pipe.

5. Key points of construction and installation (omitted).

6. Executive standards: 1) Product standard "Code for Design of Building Water Supply and Drainage" GB 50015-2003 "Lined Stainless Steel Composite Steel Pipe" CJ T 192-2004 "Safety Evaluation Standard for Drinking Water Transmission and Distribution Equipment and Protective Materials" GB T Engineering Standard "Code for Construction Quality Acceptance of Building Water Supply and Drainage and Heating Engineering" GB50242-2002.

1) To be unified, the pipeline system must be lined with stainless steel composite steel pipe fittings, lined with stainless steel composite steel valves, lined with stainless steel composite steel expansion joints, etc.;

2) Zhejiang University of Technology: composite casting pipe fittings lined with stainless steel, composite pipe welding fittings lined with stainless steel;

3) After the piping system is installed, it must be inspected with a pipeline snooping scope.

To understand its field of use, it is necessary to first understand the performance characteristics (where it distinguishes it from other similar materials) and its main uses.

1. Characteristics and uses.

Lined stainless steel composite steel pipe implements the urban construction industry standard CJ T192-2004, which is a thin-walled stainless steel pipe composite on the inner wall of the steel pipe, this bimetallic composite steel pipe greatly improves the corrosion resistance of the steel pipe in the process of water transportation, hot water transportation, gas transportation, natural gas transportation and oil transportation, the surface is smooth, the fluid resistance is small, and the high mechanical strength of the steel pipe is retained. The plastic pipe with hot melt connection is prone to water leakage and aging defects, which is an ideal product for the upgrading of steel pipes for gas transmission, water transportation and oil transportation. The specific advantages are as follows:

No scaling, no nodulation, corrosion resistance.

Composite thin-walled stainless steel pipe in the steel pipe, the material of the stainless steel pipe is 0Cr18Ni9 (AISI304 for the American standard) specified in the "GB12771-2000 stainless steel welded steel pipe for fluid transportation", because the steel contains 18% chromium, a very thin chromium oxide film is formed on the inner wall of the pipe during use, which prevents the metal from continuing to oxidize, so the stainless steel has strong corrosion resistance, not only can withstand the corrosion of water and air, but also can withstand the corrosion of weak acid and alkali. The thickness of the inner composite stainless steel pipe is millimeters, and the thickness of the galvanized steel pipe is only millimeters, and the thickness difference is doubled, and the corrosion resistance and compactness of stainless steel are stronger than the galvanized steel pipe galvanized layer. Therefore, the inner hole is reduced due to scaling and nodulation caused by the rust of the inner wall.

Second, the use of the occasion.

Please pay attention to the above sentence: it is an ideal upgrade product for gas transmission, water transportation and oil transportation steel pipes. Namely:

It is still mainly used as a tube for fluid transfer. Where are the fluids used? Too much.

Daily water supply, factory pipelines, engineering pipelines, etc. But why use a stainless steel lined clad pipe, because its advantages are corrosion resistance, no scaling, and smoother! Therefore, such as the conveyor pipe of high-end kitchen and bathroom, petrochemical and other factories, and the clothes pole that can resist corrosion, etc., should use this.

There are too many occasions to give you all the examples.

All in all, it is a corrosion-resistant, smoother, and more environmentally friendly steel pipe that is primarily used for fluid transfer. The field where it can be used is only unthinkable, and there is no use.

Classification and use of stainless steel clad steel pipe lined with stainless steel:

Lined stainless steel composite steel pipe is a branch of bimetallic composite pipe, which is a combination of two different metal pipes with special process methods, which is a combination of the advantages of two metal pipes and avoids the shortcomings of two metal pipes, and is a good metal pipe that makes the best use of it.

Lined stainless steel composite steel pipes are divided into two composite interface composite types: metallurgical composite, diffusion composite, and mechanical composite. Now it has been used in electric power, coal, urban and rural construction, shipbuilding, petrochemical, machinery, nuclear industry, and other industries.

a) Metallurgical composite lined with stainless steel clad steel pipe:

The metallurgical composite of the stainless steel clad steel pipe lined with stainless steel is composed of ** composite, surfacing welding, and double melt technology, and the two composite interfaces are metallurgically fused together. Features: composite interface bandwidth, fusion of two metals; Solid lamination; There is no boundary between thermal conduction, sound conduction, and electrical conduction; Hot and cold contraction and expansion are consistent.

As early as 1967, the United Kingdom began to experiment, and successfully developed the T310 stainless steel outer layer and No. 125 steel as the inner layer to obtain the lined stainless steel composite steel pipe. It meets the high temperature strength and corrosion resistance required by the power and pulp industries. Boilermakers all over the world are interested in bimetallic tubes as superheated materials for advanced installations (such units operate at high pressures of 80 89 kg mm and at high temperatures of 593 650 °C).

In 1976, this kind of stainless steel lined composite steel tube was installed in the power generation boiler, which solved the problem of external hearth corrosion of the boiler tube, and its corrosion resistance can be increased by 2 4 times.

2) Diffusion (diffusion) composite of stainless steel pipes lined with stainless steel

The diffusion (diffusion) composite of the stainless steel clad steel pipe lined with stainless steel is when the diffusion annealing is carried out at 1050 °C for 1 h and 4 h after mechanical composite, due to the diffusion of c atoms, etc., a second phase is formed in the microscopic region near the interface With the extension of diffusion time, the second phase distribution zone becomes wider, the interface hardness increases, and the interface shear strength also increases, which can make the stainless steel inner tube and the mild steel outer tube achieve a firm and close metallurgical bond, and its interfacial shear strength can reach more than 400 MPa. The pulp industry uses stainless steel clad steel pipes lined with stainless steel to overcome severe corrosion caused by molten sulfuric acid sulfur liquid at the furnaceside. Suitable for temperatures 250 550 ° C.

3) Lined with stainless steel composite steel pipe mechanical composite:

Lined stainless steel clad steel pipe mechanical composite is the first generation of lined stainless steel clad steel pipe production method. Usually, two steel pipes made separately are put into the other, and then through cold rolling, cold drawing of drawing dies, and hydraulic cold expansion to achieve a mechanical composite of matching. The non-diffusion junction is limited to heat exchanger tubes used in waste heat boilers for brewery heat exchangers and acetic acid units in low thermal conductivity processes below 250°C.

Stainless steel composite steel pipes lined with stainless steel are mainly used for anti-corrosion, such as petroleum, chemical, pharmaceutical, pesticide, and thermal power plants that use seawater for cooling.

I have customers who use to make clothes poles, the inside is carbon steel, the outside is stainless steel YH21ct, both are export orders.

It is mainly used in chemical equipment and other high-corrosion occasions.

How to classify stainless steel clad steel pipes lined with stainless steel?

Answer: 1. According to the use:

1) Chloride ion in tap water 50ppm stainless steel 201;

2) Chloride ions in tap water 50--100ppm stainless steel 304;

3) Chloride ions in tap water 100--200ppm stainless steel 304L;

4) Chloride ion in tap water 200---250ppm stainless steel 316;

5) Chloride ions in tap water 250ppm with duplex stainless steel 2205.

2. According to the compound force:

1) Appropriate amount of compounding: the composite interface bonding distance is greater than 25 measured with an electron microscope, and the composite strength is greater than MPA, and the CJ T192-2004 "Lined Stainless Steel Composite Steel Pipe" urban and rural construction industry standard is implemented. Flexible corrosive low-pressure pipelines used for water supply and drainage pipelines, pipeline direct drinking water pipelines, spray fire pipelines, purified gases, and purified liquids;

2) Interference composite: the composite interface bonding distance is measured with an electron microscope 5 25, the composite strength is 2 4MPa, and the oil and gas industry standard of SY T6623-2005 "Code for Corrosion-resistant Alloy Composite Steel Pipe Coated or Lined" is implemented;

3) Excessive recombination: The composite interface bonding distance is less than 5 with electron microscope, and the composite strength is greater than 4MPa.

3. According to the composite method:

1) Cold rolling process;

2) Drawing process;

3) Warm drawing process.