ASTM A335 Alloy Steel Pipe

ASTM A335 Alloy Steel Pipe

ASTM A335 is a specification for seamless ferritic alloy steel pipe intended for high-temperature service. The main use of ASTM A335 alloy steel pipes is in the construction of power plants, refineries, and other industrial facilities where high temperatures and pressures are encountered. These pipes are designed to withstand elevated temperatures and provide excellent resistance to corrosion and oxidation. They are commonly used in applications such as steam pipelines, boiler tubes, heat exchangers, and superheaters.

Alloy steel pipe is mainly used for high pressure and high temperature pipes and equipment in power plants, nuclear power plants, high pressure boilers, high temperature superheaters and reheaters. It is made of high-quality carbon steel, alloy structural steel and stainless heat-resistant steel, and is hot rolled (extruded, expanded) or cold rolled (drawn).
The biggest advantage of Alloy steel pipe is that it can be 100% recycled, which is in line with the national strategy of environmental protection, energy conservation, and resource conservation. The national policy encourages the expansion of the application field of high-pressure alloy pipes. At present, the proportion of alloy tube consumption in China’s total steel consumption is only half that of developed countries, and the expansion of alloy tube usage provides broader space for industry development. According to the research of the expert group of the Alloy Pipe Branch of the China Special Steel Association, the average annual growth in demand for high-pressure alloy pipe long materials in China can reach 10-12% in the future. Alloy pipe is defined as a steel pipe based on the material used in production (i.e. material), and as the name suggests, it is a pipe made of alloy; Seamless pipe is defined according to the production process (seamless seam) of steel pipes, which is different from seamless pipe in that it includes straight seam welded pipe and spiral pipe.

Alloying elements

The addition of Molybdenum (“Moly”) increases the strength of the steel and its elastic limit, enhances the steel resistance to wear, its impact qualities, and the hardenability. It also improves the resistance to softening, makes chromium steel less prone to embrittlement, and prevents pitting.

Chromium, a key element also for stainless steel alloys, prevents steel oxidation at elevated temperatures and increases the resistance of steel to corrosion. It enhances the tensile, yield, and hardness properties of low-alloy pipes at room temperatures.

Standard: ASTM A335

grade:P1, P2,P5,P9,P11,P91,P92

OD:10.3-660mm

WT:1.6-60mm

Length:5.8m-12m or random legth

Technical: Quenching & Tempering

Application: Gas fire power plant, coal fire power plant, headers and steam lines, Feed water pipes, superheaters, and reheaters.

A335 P9 Alloy Steel Pipe that covers “chrome-moly” seamless pipes with remarkable resistance to corrosion and good tensile strength at high-temperature service. Generally, ASTM A335 P11, P22, and P91 pipes are used in power generation and downstream oil and gas, P5 and P9 grades are for refinery applications.

A335 steel pipe Heat Treatment:

A335 pipes shall be reheated and furnished in the full-annealed, iso thermal annealed, or normalized and tempered condition. If furnished in the normalized and tempered condition, the minimum tempering temperature for Grades P5, P5b, P9, P21, and P22 shall be1250°F [675°C], the minimum tempering temperature for Grades P1, P2, P11, P12, and P 15 shall be 1200°F [650°C].

Pipe of Grades P1, P2, and P12, either hot-finished or cold drawn, may be given a final heat treatment at 1200°F[650°C] to 1300°F [705°C] instead of heat treatments.