Skip to content

Carbon steel pipe

Find your unique heat transfer 

solution with Murphy

About

Murphy Thermal Energy Technology was founded in 1992 and has been committed to the development of carbon steel pipe in  industry.   

Guided by customer needs, the company can customize thermal transfer products and thermal energy solutions according to customer needs, which can meet the needs of various customers and undertake the entire project from design, manufacturing to installation.

Our aim is to provide high-quality thermal energy solutions and services for the global thermal energy industry with high-quality products. 

Carbon steel pipe MurphyCarbon steel pipe Murphy
Seamless carbon steel pipe Murphy 1Seamless carbon steel pipe Murphy 1
Murphy carbon steel pipeMurphy carbon steel pipe

DESIGN AND DEVELOPMENT

We focus on providing the most suitable fin tube design for our customers, with a strong design team we make every effort to meet clients requirement.

OEM/ODM SERVICE

With strong design team we accept all the OEM and ODM orders. Our production lines include customer’s labels and trademarks.

ORDER

We manufacture and deliver according to your needs.

Gallery

Murphy seamless carbon steel pipe

Carbon steel pipe is made of steel ingots or solid round steel through perforation into capillary tube, and then made by hot rolling, cold rolling or cold drawing. Carbon steel pipe has an important position in the steel pipe industry.

Murphy stainless steel tube

                         

 

Why we use carbon steel pipe?

 

What is carbon steel pipe

Carbon steel is carbon steel with a carbon content of less than 0.25%. Because of its low strength, low hardness and softness, it is also called mild steel. It includes most ordinary carbon structural steels and some high-quality carbon structural steels, most of which are used for engineering structural parts without heat treatment, and some are used for mechanical parts that require wear resistance after carburizing and other heat treatments.
 

The raw material of the carbon steel pipe is a round tube blank. The round tube blank is cut by a cutting machine into a blank with a length of about 1 meter, and then sent to the furnace for heating via a conveyor belt. The billet is fed into the furnace and heated at a temperature of approximately 1200 degrees Celsius. After the round tube billet comes out of the furnace, it is pierced through a pressure punching machine. After piercing, the round tube billet is cross-rolled, continuous-rolled or extruded by three rolls. 

After squeezing, take off the tube and calibrate. The sizing machine uses a tapered drill bit to rotate at high speed into the steel blank to punch holes to form steel pipes. The inner diameter of the steel pipe is determined by the length of the outer diameter of the drill bit of the sizing machine. After the steel pipe is sized, it enters the cooling tower and is cooled by spraying water. After the steel pipe is cooled, it will be straightened. After straightening, the steel pipe is sent to the metal flaw detector (or hydraulic test) by the conveyor belt for internal flaw detection.

Carbon steel pipe type

There are two types of steel tubes: hot rolled and cold rolled (drawn) steel tubes.

Hot rolled carbon steel pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes and other steel pipes.

Cold rolled (dial) carbon steel pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, and other steel pipes, as well as carbon thin-walled steel pipes, alloy thin-walled steel pipes, and stainless steel pipes. 

Rusty thin-walled steel pipe, special-shaped steel pipe. The outer diameter of hot-rolled seamless pipe is generally greater than 32mm and the wall thickness is 2.5-75mm, the outer diameter of cold-rolled seamless steel pipe can be up to 6mm, the wall thickness can be up to 0.25mm, the outer diameter of thin-walled pipe can be up to 5mm, and the wall thickness is less than 0.25mm. Cold rolling has higher dimensional accuracy than hot rolling.

General carbon steel pipe: It is made of 10, 20, 30, 35, 45 and other high-quality carbon steels such as 16Mn, 5MnV and other low-alloy structural steels or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other alloy steels by hot rolling or cold rolling. Seamless pipes made of low carbon steel such as 10 and 20 are mainly used for fluid transportation pipelines. 

Seamless pipes made of medium carbon steel such as 45 and 40Cr are used to manufacture mechanical parts, such as stressed parts of automobiles and tractors. 

Carbon steel pipes are generally used to ensure strength and flattening tests. Hot-rolled steel pipes are delivered in hot-rolled state or heat-treated state; cold-rolled steel pipes are delivered in heat-treated state.

Seamless carbon steel pipes types:

Seamless steel tubes are divided into two types: hot-rolled and cold-rolled (dial) seamless steel tubes.
Hot-rolled seamless steel pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes and other steel pipes.


Cold rolled (dial) seamless steel pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, and other steel pipes, as well as carbon thin-walled steel pipes, alloy thin-walled steel pipes, Stainless thin-walled steel pipes, special-shaped steel pipes. 

The outer diameter of hot-rolled seamless pipe is generally greater than 32mm, and the wall thickness is 2.5-75mm. The diameter of cold-rolled seamless pipe can be up to 6mm and the wall thickness can be up to 0.25mm. 

The outer diameter of thin-walled pipe can be up to 5mm and the wall thickness is less than 0.25mm. Cold rolling has higher dimensional accuracy than hot rolling.

General seamless carbon steel pipe: It is made of 10, 20, 30, 35, 45 and other high-quality carbon steels such as 16Mn, 5MnV and other low-alloy structural steels or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other alloy steels by hot rolling or cold rolling. 

Seamless pipes made of low carbon steel such as 10 and 20 are mainly used for fluid transportation pipelines. Seamless pipes made of medium carbon steel such as 45 and 40Cr are used to manufacture mechanical parts, such as stressed parts of automobiles and tractors. 

Generally, seamless steel pipes must be used for strength and flattening tests. Hot-rolled steel pipes are delivered in hot-rolled state or heat-treated state; cold-rolled steel pipes are delivered in heat-treated state.

 Seamless carbon steel pipe application

Seamless steel tubes for low and medium pressure boilers: used to manufacture various low and medium pressure boilers, superheated steam tubes, boiling water tubes, water wall tubes, and superheated steam tubes for locomotive boilers, large smoke tubes, small smoke tubes and arched brick tubes.

Use high-quality carbon structural steel hot-rolled or cold-rolled (dial) seamless steel pipe. It is mainly made of No. 10 and No. 20 steel. In addition to ensuring the chemical composition and mechanical properties, a hydraulic test, such as crimping, flaring, and flattening, is required. Hot-rolled products are delivered in a hot-rolled state, and cold-rolled products are delivered in a heat-treated state.

High-pressure boiler steel pipes: High-quality carbon structural steel, alloy structural steel and stainless heat-resistant steel seamless steel pipes mainly used to manufacture high-pressure and above steam boiler pipes. These boiler pipes are often working under high temperature and high pressure. The pipe will be oxidized and corroded under the action of high temperature flue gas and water vapor, so the steel pipe is required to have high durability, high oxidation resistance, and good structural stability.

The steel grades used are: high-quality carbon structural steel grades 20G, 20MnG, 25MnG; alloy structural steel grades 15MoG, 20MoG, 12CrMoG, 15CrMoG, 12Cr2MoG, 12CrMoVG, 12Cr3MoVSiTiB, etc.;

In addition to ensuring chemical composition and mechanical properties, high-pressure boiler tubes of 1Cr18Ni9 and 1Cr18Ni11Nb are commonly used in rust-resistant heat-resistant steels. They must be subjected to hydrostatic tests, as well as flaring and flattening tests. The steel pipe is delivered in a heat-treated state. In addition, there are also certain requirements for the microstructure, grain size, and decarburized layer of the finished steel pipe.

Seamless steel pipes for geological drilling and oil drilling: use drilling rigs to drill wells for the exploration of underground rock structure, groundwater, oil, natural gas and mineral resources. Oil and natural gas exploitation is even more inseparable from well drilling. Seamless steel pipes for geological drilling are the main equipment for drilling, including core outer tubes, core inner tubes, casings, and drill pipes.

Because drilling pipes need to be deep into the formation depth of several kilometers, the working conditions are extremely complicated. The drill pipe is subjected to stresses such as tension, compression, bending, torsion, and uneven impact load, and is also subject to mud and rock wear. Therefore, pipe materials are required It must have sufficient strength, hardness, wear resistance and impact toughness.

The commonly used steel grades are 45MnB, 50Mn of DZ45; 40Mn2, 40Mn2Si of DZ50; 40Mn2Mo, 40MnVB of DZ55; 40MnMoB of DZ60 and 27MnMoVB of DZ65. The steel pipes are delivered in a heat-treated state.

Petroleum cracking pipe: seamless pipes for furnace pipes, heat exchanger pipes and pipelines used in petroleum refineries. Commonly used high-quality carbon steel (10, 20), alloy steel (12CrMo, 15CrMo), heat-resistant steel (12Cr2Mo, 15Cr5Mo), stainless steel (1Cr18Ni9, 1Cr18Ni9Ti) manufacturing.

In addition to the certified chemical composition and various mechanical properties of the steel pipe, it is also necessary to ensure the water pressure, flattening, flaring and other tests, as well as surface quality and non-destructive inspection. The steel pipe is delivered under heat treatment.

Stainless steel pipe: Hot-rolled and cold-rolled stainless steel pipes of various stainless steels are widely used in petroleum and chemical equipment pipelines and stainless steel structural parts for various purposes. In addition to ensuring chemical composition and mechanical properties, they are used as steel pipes that can withstand fluid pressure. To ensure that the water pressure test is qualified. All kinds of special steel pipes must be guaranteed according to the stipulated conditions.

The difference between stainless steel and carbon steel pipe

 

Stainless steel and carbon steel are the same body, both are steel. Steel containing only carbon is called carbon steel, while stainless steel is steel with high alloy content added to prevent rust.

 

 The production process is different:

Carbon steel pipes are made by perforating steel ingots or solid round steel to form capillaries, and then hot rolling, cold rolling or cold drawing.

Stainless steel pipes can be divided into equal-section pipes and variable-section pipes according to the shape of the vertical section. Variable cross-section tubes include tapered tubes, stepped tubes, periodic cross-section tubes, etc.

Different in nature:

1. Carbon steel pipe: Capillary tube is formed by perforating steel ingot or solid round steel, and then hot rolled, cold rolled or cold drawn.

2. Stainless steel pipe: is a hollow long round steel.

Anti-corrosion and wear resistance:

Stainless steel refers to an alloy resistant to weakly corrosive media (such as air, steam and water) and chemically corrosive media (such as acids, alkalis and salts). This effect is mainly attributed to the addition of chromium, the element of stainless steel. When the chromium element content exceeds 12%, an oxide film is formed on the surface of the stainless steel, which is known as a passivation film. The oxide film is not easily soluble in a certain medium, and has a high isolation effect and high corrosion resistance.

Carbon steel refers to an iron-carbon alloy with a carbon content of less than 2.11%, also known as carbon steel. Its hardness is much higher than stainless steel, but its weight is greater and its plasticity is lower, and it is usually “too hard and easy to fold” and rust easily.

 

Different applications:

The raw material of carbon steel pipe is round tube billet. The round tube blank is cut by a cutting machine to form a blank about 1 meter in length, and then the blank is sent to the furnace and heated by the conveyor belt. The billet is fed into the furnace and heated at a temperature of approximately 1200 degrees Celsius.

Stainless steel pipe is a hollow long round steel, widely used in petroleum, chemical, medical, food, light industry, machinery and equipment and other industrial pipelines and mechanical structural parts.

Different characteristics:

1. Carbon steel pipe: Carbon steel pipe is divided into hot-rolled and cold-rolled (drawn) steel pipes. Hot rolled carbon steel pipes are divided into ordinary steel pipes, medium and low pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes and other steel pipes.

2. Stainless steel pipe: Brinell hardness is the most widely used in stainless steel pipe standards. The indentation diameter is often used to indicate the hardness of the material, which is intuitive and convenient. However, it does not apply to steel pipes made of harder or thinner steel.

For more details