What is Alloy Steel Pipe?

Alloy steel pipes are tubular with higher percentages, than standard carbon steel pipes, of alloying elements as Molybdenum (Mo), Chromium (Cr), Nickel, etc.

ASTM A335 Grade P91 Seamless Alloy Steel Pipe
ASTM A335 Grade P91 Seamless Alloy Steel Pipe

Alloy steel pipe is a versatile grade that is alloyed with different alloying elements. The alloying elements in the alloy steel pipe impact its corrosion resistance, hardness, and toughness. Iron and carbon are the primary elements with the other additions. These pipes are highly versatile and can be easily welded in place. The Alloy pipe price is dependent on its chemical composition and alloying elements.

What is CRA clad pipe?

CRA is a corrosion resistant alloy grade. A CRA cladded pipe has conventional carbon or low alloy steel. The cladding material of the pipe is metallurgically bonded on their internal and external surface. The cladding material is economically favourable for producing an alloy steel boiler pipe and other pipes that have to work under stress.

What type of alloy pipe welding is used on pipelines?

Pipelines of alloy steel can be welded using a variety of welding procedures. Some common methods include shielded arc welding, gas metal arc welding in both MIG and MAG welded methods. Flux cored arc welding, submerged arc welding, and tungsten inert gas can also be used to weld an alloy pipe.

Advantages of Seamless Alloy Steel Pipe

Alloy steel seamless pipe is manufactured with the best technology and has good strength. The alloy steel pipes have good corrosion resistance, thermal conductivity, better solderability, and electrical conductivity. Alloy steel pipe suppliers supply pipes that have increased hardenability and are light but very durable.

alloy steel categories types grades

Alloy Steel Pipe Specification and Size :

Product Name Executive Standard Dimension (mm) Steel Code / Steel Grade
Seamless Ferritic and Austentic Alloy Steel Boiler, Superheater and Heat-Exchanger Tubes ASTM A213 Ø10.3~426 x WT1.0~36 T5, T9, T11, T12, T22, T91
Seamless Ferritic Alloy Steel Pipes for High Temperature Use ASTM A335 Ø1/4″~42″ x WT2~120mm P5, P9, P11, P12, P22, P91, P92
Seamless Carbon and Alloy Steel for Mechanical Tubing ASTM A519 Ø16″~42″ x WT10~100mm 4130, 4130X, 4140
Seamless Ferritic Alloy Steel Pipes for High Temperature Use EN10216-2 Ø8″~42″ x WT15~100 13CrMo4-5, 1-CrMo9-10, X10CrMoVNb9-1, 15NiCuMoNb5-6-4


Alloy steel seamless pipe is ideally suitable for chemical, petrochemicals and other energy-related applications. It has characteristics of high corrosion resistance and can be used in a wide range of industrial sectors.

– Chemical industries
– Petrochemical industries
– Energy-related applications

What steel can be defined as low-alloy steel?

Among alloy steels, when additions of alloys such as nickel, chromium and total molybdenum alloy content can range from 2.07% to levels immediately below those of stainless steel, containing a minimum of 10% Cr, they are defined as low-alloy steels. As with steels in general, low-alloy steels can be classified according to:

• Chromium-Molybdenum Steel

This series of low alloy steel contains 0.5% to 9% Cr and 0.5% to 1% Mo. Your carbon

The average content is less than 0.20%. The Cr content improves its antioxidant and anticorrosive capacity, and Mo increases its resistance in high temperature conditions; Steel supply conditions are usually eliminated by annealing or standardization and tempering processes. Chromium molybdenum steel has been widely used in areas such as oil and gas industry, power plants and other high-temperature applications.

Available standards: AISI 4140 / AISI 4130

• Outdoor steel (low carbon low-alloy steel)

Weathering steel is a high-strength steel between ordinary steel and stainless steel, better known under the brand name Cor-ten steel, is a group of steel alloys that were developed to obviate the need for coating and form a stable appearance of rust if exposed to the weather for several years. Steel weathering has a higher resistance to atmospheric corrosion compared to other steels. In simple terms, the steel is allowed to rust and the rust to form a protective layer that slows down the rate of future corrosion.

Available standards:

Boards: ASTM A242 / ASTM A606 Type 4 / ASTM A588

• Nickel steel (Low temperature and low alloy steel)

Low alloy service low temperature steel is formed by adding 2.5% to 3.5% Ni in carbon steel to improve its low temperature strength. Ni can strengthen the ferrite matrix while reducing the Ar3 (temperature of the third transformation), which helps the formation of fine grains. In addition to the normalization treatment during the production process. Average steel in a low temperature environment will have higher strength but lower elongation and toughness, therefore increasing the chance of brittle fracture. If steel is needed in a low temperature environment, it is essential to have superior resistance at low temperature. Any steel suitable for this purpose is called low-temperature service steel or nickel steel.

Available standards: ASTM A265 / ASTM A203

• High performance steel and high tensile strength

This series of low-alloy steel is added Mn, Ni, Cr and Mo, etc., it can increase the strength of ferrite matrix; improve the tendency to harden; and allows better control of grain size. This kind of steel in welded conditions can meet the demand for high strength, corrosion resistance or improve notch strength and other mechanical properties. This type of steel has a good welding capacity with a yield strength of 70 to 120 ksi and a tensile strength of 90 to 150 ksi.

Available standards:

  • Plates: ASTM A204 Gr. A, B, C / ASTM A336 / ASTM A387
  • Tube and tube: ASTM A209 / ASTM A335 / ASTM A213 / ASTMA182

The main material of the alloy pipe

Alloy pipe is a kind of seamless steel pipe, but its high temperature, low temperature strength, corrosion resistance is higher than the average seamless steel pipe, because it contains more Cr, so the alloy pipe in oil, electricity, boilers and other industries pay for a wide range of applications.

It is generally used for low or medium pressure boilers (working pressure ≦ 5.88mpa, working temperature ≦ 450°C) of the heating surface tube; For high pressure boiler (working pressure ≧ 9.8mpa, operating temperature between 450°C-650°C) of heating surface pipe, province coal, superheater, reheater, petrochemical industry pipe.

The main material: 12Cr1MoV, P22 (10CrMo910), T91, P91, P9, T9, WB36, Cr5Mo (P5, STFA25, T5,), 15CrMo (P11, P12, STFA22) 13CrMo44;

Application standards: DIN17175-79, JISG3467-88, JISG3458-88, GB5310-95, GB9948-88, ASTMA335/A335m, ASTMA213/A213m;

For example, GB5310-1995 (high-pressure boiler seamless steel pipe), mainly used for high temperature resistant and transmission fluid transmission collection box and pipeline in power plant and nuclear power plant boiler. Typical materials include 20G, 12Cr1MoVG, 15CrMoG and ect.

Heat-resistant alloy pipe standards as follows:

16Mo A335 P1
A369 FP1
A250 T1
A209 T1
12CrMo A335 P2
A369 FP2
A213 T2
15CrMo A335 P12
A369 FP12
A213 T12
12Cr1MoV A335 P11
A369 FP12
A199 T11
A213 T11 
Cr2Mo10MoWVNb A335 P22
A369 FP22
A199 T22
A213 T22
Cr5Mo A335 P5
A389 FP5
A213 T5
A335 P9
A369 FP9
A199 T9
A213 T9

Classification of steel alloy according to alloy content

Steel is composed of iron and carbon and other elements. Alloy steels are manufactured by combining carbon steel with alloying elements such as manganese, silicon, nickel, titanium, copper, chromium and aluminum to improve their strength, hardenability, corrosion resistance, formability and weldability. Depending on the content of the alloying element, alloy steel can be divided into three types: low-alloy steel (less than 5% alloy), medium alloy steel (more than 5% but less than 10% alloying elements ), high-alloy steel (10% or more than 10% of alloying elements.) The most commonly used grades of alloy steel are low-alloy steel and high-alloy steel.

High-strength low-alloy steel

Typically, iron-based alloys constitute a category of ferrous materials that exhibit superior mechanical properties to simple carbon steels as a result of the addition of alloying elements that can harden to high strength. High-strength low-alloy steels are designed to provide better mechanical properties or greater resistance to atmospheric corrosion than conventional carbon steels.

Applications: Heavy road and off-road vehicles, oil and gas pipelines, agricultural and construction machinery, storage tanks, mining and rail cars, barges and dredgers, snowmobiles, lawnmowers and passenger vehicle components. Bridges, offshore structures, power transmission towers, light poles, and building beams and panels are additional uses of these steels. The choice of a specific high-strength steel depends on thickness reduction, corrosion resistance, formability and weldability.

A common steel alloy is AISI 4130. Another type is AISI 4340, a very high strength alloy in this 300M family, which can be used in high-strength applications. This family of steels is very prone to corrosion and must be plated to avoid corroding in most environments.

High alloy steel

This type of steel contains 10% or more than 10% alloying elements. High-alloy steels are difficult to manufacture by welding and forming, making it expensive than ordinary steels. High alloy steels have high strength, hardness, corrosion resistance, wear resistance, creep strength but relatively low hardness. While a high-alloy steel is one that has a large amount of alloying element, it is not necessary in any specific proportion. of alloying element is more

Application: High alloy steels are widely used for their corrosion resistance in aqueous media at or near room temperature and for service in hot gases and liquids in high and high temperature applications, corrosive environments and also as tool steels.

There are kinds of high-alloy steel such as tool steel, high Ni steel, austenitic stainless steel, Fe-Ni based alloy. Stainless steel is a special class of alloy steel, which has a main alloying element such as Ni and Cr in a specific equivalent (according to the Scheaffler diagram) along with another alloying element. The variation in proportion provides different types of stainless steels.