Alloy steel pipe is a kind of seamless steel pipe, its performance is much higher than the general seamless steel pipe, because this steel pipe inside containing Cr, high temperature resistance, low temperature, corrosion-resistant performance of other non-pipe joints not match, so the more extensive use of alloy tube in the petroleum, aerospace, chemical, electric power, boiler, military, and other industries.
The alloy steel pipes adopt high quality carbon steel, alloy structural steel and stainless & heat resisting steel as raw material through hot rolling or cold drawn to be made.
Chrome Moly Pipe
ASTM A335 Pipe is a seamless ferritic Alloy-Steel Pipe for high temperature service.
Low Temperature Pipe
ASTM A333 specification describes Low temperature service pipe applied up to minus 150 degrees Fahrenheit.
Alloy pipes specification and size
Alloy steel is a series of alloy which its main content is steel. To add different metal elements with different ratios in steel can change the mechanical properties of alloy steel.
ASTM/ ASME
American Society for Testing and Materials(ASTM), American Society of Mechanical Engineers (ASME)
| Description | Standard | Dimension (mm) | Steel code/ Steel grade |
|---|---|---|---|
| Carbon and alloy steel mechanical tubing, either hot-finished or cold-finished | ASTM A519 | 20-180 x 2-30 | A1, C |
| Seamless Ferritic and Austenitic Alloy Steel Boiler, Superheater and Heat-exchanger Tubes | ASTM A213 09 | 10.3-426 x 1.0-36 | T5, T5b, T9 , T11, T22 ,T91 |
| Seamless Carbon and Alloy Steel for Mechanical Tubing | ASTM A333 | 1/4"-42" x SCH20-XXS | Grade1 Gr. 3,Gr..6, Gr.8 , Gr. 9 |
| Seamless ferritic alloy-steel pipe for high-temperature service | ASTM 335/335M | 1/4"-42" x SCH20-XXS | P5, P9 ,P11, P91, P22, P92 |
DIN/EN- European Standards for steel
Germany Safety(GS), Deutsches Institut für Normung(DIN)
| Product name | Executive standard | Dimension (mm) | Steel code/ Steel grade |
|---|---|---|---|
| Seamless Steel Tubes for Elevated Temperature | DIN 17175 | 10-762 x 1.0-120 | St35.8,St45.8, 10CrMo910, 15Mo3, 13CrMo44, STPL340, STB410, STB510, WB36 |
| Seamless steel tubes for pressure purposes | EN10216 | 4.0-60.0 x 0.5-8 5-7 m manufacturing lenght | P235GH TC1, P235GH TC2, 16Mo3 |
| Seamless precision steel tube applications | EN 10305-1 | 13.5-165.1 x 1.8-4.85 | St33.2 |
| Seamless Precision Steel Tube | DIN 2391 | 4.0-60.0 x 0.5-8 | St35, St45, St52 |
JIS
Japanese Industrial Standards (JIS) specifies the standards used for industrial activities in Japan.
| Product name | Executive standard | Dimension (mm) | Steel code/ Steel grade |
| Carbon steel/Alloy steel boiler and heat exchanger tubes | JIS G3461,2 | 19.05-114.3 x 2.0-14 | G3461(STB340, STB410, STB510) G3462(STBA22, STBA23) |
| Heat resistant alloy steel pipes that are used for high temperature conveying fluid pipes for heaters and boiler tubes. | JIS G3458 | 10.5-660.4 mm | STPA 12, STPA 20, STPA 22, STPA 23, STPA 24, STPA 25, STPA 26 |
Application of alloy steel pipes
Alloy steel pipes are ideally suitable for chemical, petrochemicals, and other energy-related applications.
The alloy steel pipe adopts high quality carbon steel, alloy structural steel and stainless & heat resisting steel as raw material through hot rolling or cold drawn to be made.
Alloy steel can be used in process area where carbon steel has limitation such as
Industries we serve
Our team of experienced sales specialists proudly partners with gas and chemical processors, power generation plants, oil refineries, and related industries to offer piping components and value-added services.
As an important element of steel products, alloy steel pipe can be divided into seamless steel pipe and welded steel pipe according to the manufacturing technique and tube billet shape.
Here you can see the common alloy steel grade that you will come across.
- For Pipes: ASTM A335 Gr P1, P5, P11, P9
- For Wrought Fittings: ASTM A234 Gr.WP5, WP9, WP11
- For Forged Fittings: ASTM A182 F5, F9, F11 etc.
What requirements should alloy steel pipe application meet
The transportation of kinds of gases or liquids in production needs to rely on alloy steel pipe. This shows that the actual role of alloy steel pipe application is important. High temperature resistant and low temperature resistant is the tolerance of temperature. In the practical application of alloy steel pipe, there will be many materials need to be transported. However their temperatures are not the same. So this can be the basic requirement to alloy steel pipe. It needs more corrosion resistance. Corrosion resistant material is the best material during transporting, because it is corrosion resistant. So it can be used in more occasions. And it is definitely very convenient for users.
The biggest advantages of alloy steel pipe
Can be 100% recycled, environmentally friendly, energy-saving, resource conservation, national strategy, national policy to encourage the expansion of the field of application of high-pressure alloy pipe. Of alloy steel pipe total consumption accounted steel in the proportion is only half of the developed countries, to expand the field of use of the alloy steel pipe to provide a wider space for the development of the industry. The future needs of the average annual growth of China’s high-pressure alloy steel pipe long products up to 10-12%.
Specification, standard and identification of alloy steel pipes
Alloy Steel pipe contains substantial quantities of elements other than carbon such as nickel, chromium, silicon, manganese, tungsten, molybdenum, vanadium and limited amounts of other commonly accepted elements such as manganese, sulfur, silicon, and phosphorous.
Honed tube
Honed Tubes are ready to use for hydraulic cylinder applications without further ID processing.
Boiler tubes
Boiler tubes are used in heat exchange appliances in which the energy is transferred from one medium to the other.
Alloying Elements
Commonly used alloying elements and their effects are listed in the table given below.
| Alloying Elements | Effect on the Properties |
|---|---|
| Chromium | Increases Resistance to corrosion and oxidation. Increases hardenability and wear resistance. Increases high temperature strength. |
| Nickel | Increases hardenability. Improves toughness. Increases impact strength at low temperatures. |
| Molybdenum | Increases hardenability, high temperature hardness, and wear resistance. Enhances the effects of other alloying elements. Eliminate temper brittleness in steels. Increases high temperature strength. |
| Manganese | Increases hardenability. Combines with sulfur to reduce its adverse effects. |
| Vanadium | Increases hardenability, high temperature hardness, and wear resistance. Improves fatigue resistance. |
| Titanium | Strongest carbide former. Added to stainless steel to prevent precipitation of chromium carbide. |
| Silicon | Removes oxygen in steel making. Improves toughness. Increases hardness ability |
| Boron | Increases hardenability. Produces fine grain size. |
| Aluminum | Forms nitride in nitriding steels. Produces fine grain size in casting. Removes oxygen in steel melting. |
| Cobalt | Increases heat and wear resistance. |
| Tungsten | Increases hardness at elevated temperatures. Refines grain size. |
Recommended alloy steel pipes
Alloy steel pipe FAQs:
Our team of experienced sales specialists proudly partners with gas and chemical processors, power generation plants, oil refineries, and related industries to offer piping components and value-added services.
The most important and desired changes in alloy steel are:
Alloy steels are made by combining carbon steel with one or several alloying elements, such as manganese, silicon, nickel, titanium, copper, chromium and aluminum. These metals are added to produce specific properties that are not found in regular carbon steel. The elements are added in varying proportions (or combinations) making the material take on different aspects such as increased hardness, increased corrosion resistance, increased strength, improved formability (ductility); the weldability can also change.
- Increased hardenability.
- Increased corrosion resistance.
- Retention of hardness and strength.
Nearly all alloy steels require heat treatment in order to bring out their best properties.
Alloying Elements & Their Effects:
- Chromium – Adds hardness. Increased toughness and wear resistance.
- Cobalt – Used in making cutting tools; improved Hot Hardness (or Red Hardness).
- Manganese – Increases surface hardness. Improves resistance to strain, hammering & shocks.
- Molybdenum – Increases strength. Improves resistance to shock and heat.
- Nickel – Increases strength & toughness. Improves corrosion resistance.
- Tungsten – Adds hardness and improves grain structure. Provides improved heat resistance.
- Vanadium – Increases strength, toughness and shock resistance. Improved corrosion resistance.
- Chromium-Vanadium – Greatly improved tensile strength. It is hard but easy to bend and cut.
Advantages of alloy steel pipes
An Alloy Steel Pipe is used in applications which require moderate corrosion resistance properties with good durability and at an economical cost.
High Strength
Some alloy steels like chrome moly pipe because of the chemical makeup of Molybdenum (Mo) and Chromium (Cr). Molybdenum increases the strength of steel as well as the elastic limit, resistance to wear, impact qualities, and hardenability. Chrome raises the tensile strength, yield, and hardness. The composition chrome moly alloy steel pipe make it ideal for use in power plants, refineries, petro chemical plants, and oil field services where fluids and gases are transported at extremely high temperatures and pressures.
Corrosion Resistance
When metals encounter oxygen, they can undergo oxidation reactions. This, in turn, causes corrosion.
Chromium (or chrome), is virtually irreplaceable in resisting oxidation at elevated temperatures, making Alloy Steels more resistant to corrosion than most metals. This allows them to maintain their integrity for longer than other metals, especially in marine environments where corrosion is particularly problematic.
Low-Expansion
Some alloy steels have an extremely low rate of thermal expansion or a very consistent and predictable pattern of expansion in specific temperature ranges. This makes them useful when you need a pipe that can maintain a uniform shape and size despite hot environments.
For example, Iron-36% nickel alloy almost doesn’t expand at all during moderate changes in temperatures. And when you add cobalt to the nickel and iron, you get a high-strength alloy steel that has a constant modulus of elasticity and a low coefficient of expansion.
Shape Memory
Sometimes, a metallic material is needed that can return to its previous shape when it experiences heat. This type of material is called a shape memory alloy, and there are very few available on the market. Some alloy steel, however, have this characteristic, with nickel-titanium alloys being one of the most prominent shape memory alloys.
Magnetic Permeability
Alloy Steels also have unique and interesting magnetic permeability characteristics. This has allowed them to become an integral component in designs for switchgear as well as direct current motors and generators.
These advantages have made alloy steels tubes & pipes, a popular material in a number of applications, including:
- The petrochemical industry
- Aircraft turbines
- Medical engineering
- Steam turbine power plants
- Nuclear power plants
- Environment-Friendly
100% recycled, it is suitable for the national strategy of environmental protection, energy-saving and resource-saving. Therefore, the national policy encourages the expansion of the high pressure alloy steel pipe applications. At present, the proportion of the total alloy steel tube is half of the developed countries. The applications of alloy steel pipe provide a broad space for the industry development. According to the research of the China association of special steel alloy pipe expert group, our country’s high pressure alloy steel pipe material demand grows by an average of up to 10-12%. Therefore, the national policy encourages the expansion of the high-pressure alloy steel pipe applications.
Difference between carbon steel and alloy steel
Steel is an alloy that mostly contains iron. But its properties can be changed to suit specific requirements by adding certain other elements. This explains the differences between alloy steel and carbon steel. As the name indicates, alloy steel has other elements added to it whereas carbon steel is a kind of steel having higher carbon content. There are other differences also that will be talked about in this article.
Carbon steel
Carbon steel is also known as the iron-carbon alloy containing less than 2% carbon WC.
Generally also contain small amounts of silicon, manganese, sulfur, phosphorus and carbon steel, in addition to carbon use can be divided into carbon steel and carbon structural steel, carbon tool steel, and ease of cutting structural steel three categories. Carbon structural steel is divided into building structural steel and machinery manufacturing structural steel two kinds.
According to the carbon steel, carbon content can be divided into low-carbon steel (WC ≤ 0.25%), medium carbon steel (WC0.25% - 0.6%) phosphorus, sulfur content and high-carbon steel (WC> 6%) can be divided into ordinary carbon steel (containing phosphorus, sulfur higher), high-quality carbon steel (containing phosphorus, low sulfur) and high quality steel (phosphorus, sulfur less), generally, the higher carbon content, the higher the hardness, higher strength but lower ductility.
Alloy steel
Alloy steel is a type of steel that has presence of certain other elements apart from iron and carbon. Commonly added elements in alloy steel are manganese, silicon, boron, chromium, vanadium and nickel. The quantity of these metals in alloy steel is primarily dependent upon the use of such steel. Normally alloy steel is made to get desired physical characteristics in the steel.
Alloy steels are divided into low alloy steels and high alloy steels. When the percentage of added elements goes past 8 (in terms of weight), the steel is referred to as high alloy steel. In cases where added elements remain below 8% by weight of the steel, it is a low alloy steel. Low alloy steels are more common in the industry. In general, addition of one or more of such elements to steel makes it harder and more durable. Such steel is also resistant to corrosion and tougher than normal steel. To alter the properties of steel, it needs heat treatment when elements are added to it.
To keep the alloy steel weldable, carbon content needs to be reduced. As such carbon content is lowered down to 0.1% to 0.3% and alloying elements are also decreased in proportion. These alloys of steel are known as high strength, low alloy steels. You would be surprised to know that stainless steel is also an alloy steel with a minimum of 10% of chromium by weight.
In brief Alloy Steel vs Carbon Steel:
- There are many types of steels such as alloy steel and carbon steel
- As the names signify, alloy steel is the type of steel formed by addition of various other elements in the steel through heat treatment.
- Carbon steel on the other hand is steel that has primarily carbon in it and does not require any minimum percentage of other elements.
- Carbon steel is the type of steel predominantly used in the US
- Stainless steel is a kind of alloy steel
How do alloying elements affect the performance of cryogenic steels?
We usually call the steel used the temperature range -10 to -273℃ as low-temperature steel or cryogenic steel According to alloying element content and structure, cryogenic steels can be divided into: Aluminum killed C-Mn steel such as 06MnVTi, 06MnVal, 09Mn2Vre, 06MnNb steel, low alloy ferric body low-temperature steel 0.5Ni, 2.5Ni, 3Ni, 3.5Ni, etc., Martensiform low-temperature steels such as 9Ni, 5Ni steel, high alloy austenitic low-temperature steels such as 1Cr18Ni9Ti and 20Mn23Al and so on.
The effect of alloying elements in low-temperature steels mainly refers to its effect on the low-temperature toughness of steels:
Mn
Manganese can improve obviously the low-temperature toughness of steel. Manganese mainly exists in the form of solid solution in steel and plays the role of solid solution strengthening. In addition, manganese is an element that enlarges the austenite region and reduces the transformation temperature (A1 and A3). It is easy to obtain fine and ductile ferrite and pearlite grains, which can increase the maximum impact energy and significantly reduce the brittle transition temperature. In general, the Mn/C ratio should be equal to 3, which can not only reduce the brittle transition temperature of steel, but also compensate for the decrease of mechanical properties caused by the decrease of carbon content due to the increase of Mn content.
Ni
Nickel can alleviate the tendency of brittle transition and significantly reduce the temperature of brittle transition. The effect of nickel on improving the low-temperature toughness of steel is 5 times that of manganese, that is, the brittle transition temperature decreases by 10℃ with the increase of nickel content by 1%. This is mainly because of nickel with carbon, absorbed by the solid solution and reinforcement, nickel also makes a move to the left point of eutectoid steel eutectoid point to reduce the carbon content, reduce the phase transition temperature (A1 and A2), in comparison with the same carbon content of carbon steel, decrease in the number of ferrite and refining, pearlite populations (the carbon content of pearlite is also lower than carbon steel). The experimental results show that the main reason why nickel increases the toughness at low temperature is that nickel-containing steel has more movable dislocations at low temperature and is easier to cross slip. For example, medium alloy low carbon martensiform low-temperature steel 9Ni steel, has high low-temperature toughness, can be used for -196℃. The 5Ni steel developed on the basis of 9Ni steel has good low-temperature toughness at -162~-196℃.
C
With the increase of carbon content, the brittle transition temperature of steel increases quickly and the welding property decreases, so the carbon content of low-temperature steel is limited to less than 0.2%.
P, S, Sn, Pb Sb
Phosphorus, sulfur, arsenic, tin, lead, antimony: these elements are not conducive to the low-temperature toughness of steel.
They segregate in the grain boundary, which reduces the surface energy and resistance of the grain boundary, and causes the brittle crack to originate from the grain boundary and extend along the grain boundary until the fracture is complete.
Phosphorus can improve the strength of steel, but it will increase the brittleness of steel, especially at low temperatures. The brittle transition temperature is obviously increased, so its content should be strictly limited.
O, H, N
These elements will increase the brittle transition temperature of steel. Deoxidized silicon and aluminum killed steels can improve the toughness at low temperatures, but because silicon increases the brittle transition temperature of steels, aluminum killed steels have a lower brittle transition temperature than silicon killed steels.
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