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Introduction of pipe type

Jan 19, 2020

A, steel pipe

Steel pipes are classified into seamless steel pipes and welded steel pipes according to their manufacturing methods.

Seamless steel pipes are made of high-quality carbon steel or alloy steel, and are divided into hot rolled and cold rolled (drawn). Welded steel pipes are welded from steel plates rolled into tubular shapes with butt or spiral seams. In terms of manufacturing methods, they are divided into welded steel pipes for low-pressure fluid transportation, spiral seam welded steel pipes, direct coil welded steel pipes, and welded steel pipes.

Uses: Seamless steel pipes can be used for various liquid and gas pipelines. Welded pipes can be used for water pipes, gas pipes, heating pipes, etc.

1. Welded steel pipes

1.1 Welded steel pipes and galvanized welded steel pipes for low-pressure fluid transportation

Welded steel pipe for low-pressure fluid transportation is made of carbon soft steel. It is the most commonly used small-diameter pipe in pipeline engineering. It is suitable for transporting water, gas, steam and other media. It is divided into plating according to its surface quality. Zinc pipes (commonly known as white iron pipes) and non-galvanized pipes (commonly known as black iron pipes). The zinc coating on the inner and outer walls is about 3% -6% heavier than non-galvanized . According to different pipe wall thickness, it is divided into three types: thin-walled pipe, ordinary pipe and thickened pipe. Thin-walled pipes are not suitable for conveying media, but can be used as casing.

1.2 straight seam rolled electric welded steel pipe

Straight seam rolled electric welded steel pipe can be divided into electric welded steel pipe and field welded steel pipe. Can be made into several tube wall thicknesses.

1.3 spiral seam welded steel pipe

Spiral seam welded steel pipe is divided into two types: automatic submerged arc welded steel pipe and high frequency welded steel pipe.

a. Spiral seam automatic submerged arc welded steel pipe is divided into two types of pipe A and B according to the pressure of the conveying medium. Class A pipes are generally welded with ordinary carbon steel Q235 , Q235F and ordinary low-alloy structural steel 16Mn , and Class B pipes are welded with steels such as Q235 , Q235F , Q195, etc., and are used as low-pressure fluid transport pipes.

b. Spiral seam high-frequency welded steel pipe Spiral seam high-frequency welded steel pipe, there is no unified product standard, generally using ordinary carbon steel Q235 , Q235F and other steels.

2 , seamless steel pipe

Seamless steel tubes are divided into hot rolled tubes and cold drawn (rolled) tubes according to manufacturing methods. The maximum nominal diameter of cold-drawn (rolled) pipe is 200mm , and the maximum nominal diameter of hot-rolled pipe is 600mm . In pipeline engineering, when the pipe diameter exceeds 57mm , hot rolled pipe is often used, and when the pipe diameter is less than 57mm , cold drawn (rolled) pipe is often used. There are three types of seamless steel pipes commonly used in pipeline engineering:

2.1 general seamless steel pipe

General seamless steel tubes are referred to as seamless steel tubes, and are made of ordinary carbon steel, high-quality carbon steel, ordinary low-alloy steel and alloy structural steel. They are used to make liquid pipelines or to make structures and parts.

Seamless steel pipes are supplied according to the outer diameter and wall thickness. There are multiple wall thicknesses under the same outer diameter, and the pressure range is large. Typically the length of steel, hot-rolled tubes of the 3-12.5m , cold drawn (rolled) pipe for the 1.5-9m .

2.2 the low pressure in the boiler seamless steel

The seamless steel tubes for low and medium pressure boilers are made of No. 10 and No. 20 high-quality carbon steel.


B cast iron pipe

Cast iron pipes are made of pig iron.

According to its manufacturing method, it can be divided into: sand type centrifugal socket straight pipe, continuous cast iron straight pipe and sand type iron pipe. According to the material used, it can be divided into: gray iron pipe, ductile iron pipe and high silicon iron pipe.

1 , cast iron pipe water supply

1.1 Material Sand Sand centrifugally cast centrifugally cast tube straight straight pipe of gray cast iron for the pressure fluid and gas, or water transport.

1.2 continuous cast iron straight pipe

Continuous cast iron straight pipe is the continuous cast gray cast iron pipe, which is suitable for the transportation of pressure fluid such as water and gas.

2 , cast iron drainage pipe

Ordinary drainage cast iron sockets and fittings. Flexible anti-seismic drainage cast iron straight pipe. This cast iron pipe is sealed with rubber rings and bolted. It has good flexibility and flexibility under internal water pressure. It can adapt to large axial displacement and lateral deflection, and is suitable for indoor drainage pipes of high-rise buildings, especially suitable for seismic areas.

Uses: Cast iron pipes are mostly used for water supply, drainage and gas pipeline projects.


C, non-ferrous metal pipes

1 . Aluminum and aluminum alloy tubes Aluminum and aluminum alloys refer to industrial pure aluminum with 98% aluminum and aluminum alloys with aluminum as the main body and copper, magnesium, manganese, zinc, chromium and other alloy elements. Aluminum and aluminum alloy tubes are made of industrial pure aluminum or aluminum alloy by drawing or extrusion. Aluminum has better resistance to acid corrosion.


Copper and copper alloy tubes Copper tubes are mainly made of pure copper and phosphorous deoxidized copper. They are called copper tubes or red copper tubes. Brass tubes are made of brass such as ordinary brass and lead brass.

Lead and lead alloy pipes


D, plastic tube

Plastic pipes are generally made of plastic resin as a raw material, added with stabilizers, lubricants, etc., and extruded in a pipe making machine by a plastic method. Because it has the characteristics of light weight, corrosion resistance, beautiful appearance, no bad odor, easy processing, and convenient construction, it has been increasingly used in construction projects. Mainly used as piping for tap water supply systems, drainage, exhaust and sewage sanitary pipes, underground drainage pipe systems, rainwater pipes, and threading pipes for electric wire installation and so on in building construction.

There are two types of plastic pipes: thermoplastic pipes and thermosetting plastic pipes.

The main resins used in thermoplastic pipes are polyvinyl chloride resin ( PVC ), polyethylene resin ( PE ), polypropylene resin ( PP ), polystyrene resin ( PS ), and acrylic Jing- butadiene - styrene resin ( ABS ), polybutene resin ( PB ), etc .; the main resins used in thermosetting plastics are unsaturated polyester resins, epoxy resins, phenolic resins, etc.

Below is a comparison of the characteristics and main uses of these plastic pipes.

Comparison of characteristics and main uses of several commonly used plastic pipes :

PVC pipe

Features have better tensile and compressive strength, but its flexibility is not as good as other plastic pipes, excellent corrosion resistance, the price is the cheapest of all types of plastic pipes, but it is more brittle at low temperatures. The connection methods are bonding, socket connection, flange thread connection. Mainly used for residential life, industrial and mining, agricultural water supply and drainage, irrigation, gas supply, exhaust pipes, electrical conduit, rainwater pipes, industrial anticorrosion pipes, etc.

CPVC pipe

Features outstanding heat resistance, thermal deformation temperature of 100 , excellent chemical resistance. Adhesive connection, flange thread connection. Mainly used for hot water pipes.

PE pipe

Features Light weight, good toughness, good low temperature resistance, non-toxic, cheaper price, high impact strength, but low compressive and tensile strength. Connection method: hot melt welding, flange thread connection. Mainly used for drinking water pipe, rain water pipe, gas pipe, industrial corrosion-resistant pipe PP pipe

Features Good corrosion resistance, good strength, high surface hardness, surface finish, and high temperature resistance. Connection method: hot melt welding, flange thread connection. Mainly used for chemical sewage, seawater, oil and irrigation pipes, indoor concrete floor as heating pipes for heating systems.


ABS tube

Features Excellent corrosion resistance, lighter weight, higher heat resistance than PE , PVC , but more expensive. Adhesive connection, flange thread connection. Mainly used in sanitary ware, such as sewer pipes, begging pipes, sewage pipes, underground cable pipes, high anti-corrosion industrial pipes, etc.

PB tube

The strength is between PE and PP , and the flexibility is between LDPE and HDPE . Its outstanding features are creep resistance (cold deformation), repeated winding and continuous, temperature resistance, and chemical properties. Connection method: hot-melt welding, flange thread connection. Mainly used for water supply pipes, hot and cold water pipes, gas pipes, underground buried high pipes

GRP tube

Excellent corrosion resistance, light weight, high strength and good design performance. Connection method: socket rubber connection, flange connection. Widely used petrochemical pipelines and large-diameter water supply and drainage pipelines.


E, composite pipe

There are mainly FRP plastic composite pipes, steel pipes, glass pipe composite pipes, steel-plastic composite pipes, steel-plastic composite pipes, enamel pipes, rubber-lined pipes, lead-lined cast iron pipes, and plastic-coated steel pipes.


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