ASTM A335 Alloy Steel Pipe

ASTM A335 Alloy Steel Pipe

ASTM A335 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.

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.

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.

Other alloying elements, present in various degrees in pipes of all grades are:

1. Aluminum: decreases oxygen from steelmaking
2. Boron: used to produce fine grain size and enhance steel hardness
3. Cobalt: used to enhance the steel’s heat and wear-resistance
4. Manganese: gives better steel hardenability
5. Nickel: Enhances toughness, hardenability, and impact strength at low temperatures
6. Silicon: decreases oxygen, enhances hardenability and toughness
7. Titanium: prevents precipitation of chromium carbide
8. Tungsten: refines steel grain size and enhance the steel hardness, especially at high temperatures
9. Vanadium: gives steel enhanced fatigue resistance

As mentioned, low-alloy steels have a total amount of alloying elements below 5%; high alloy steel has a higher percentage of these elements.

ASTM A335 Alloy Steel Pipe MECHANICAL PROPERTIES

ASTM A335 Alloy Steel Pipe Heat Treatment:

ASTM A335 Alloy Steel Pipe 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.