A335 Gr P5 P9 Alloy Seamless Steel Pipe With High Strength

Product Description

ASTM A335 Seamless Alloy Steel Pipe With High Strength A335 Gr P5, P9, P11, P22 , P91,P92 Alloy Seamless Steel Pipe

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,

super heaters 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 in downstream oil and gas, P5 and P9 grades are

for refinery applications.

How to define alloy pipes?

Alloy pipes are tubular with higher percentages, than standard carbon steel pipes, of alloying elements

as Molybdenum (Mo), Chromium (Cr), Nickel, etc. Actually, the ASTM A335 covers “low-alloy” steel pipes,

i.e. pipes that have a total amount of alloying elements below 5%. The addition of higher percentages of

alloying elements (example Nickel and Chromium) transforms the steel into higher alloys, like stainless steel,

duplex, up to super-alloyed materials like Inconel, Hastelloy, Monel, etc.

Alloy steel pipes are used in the energy industry for high temperature and very low-temperature service

(cryogenic), or for applications with very high pressures.

ASTM A335 alloy steel pipes fit ASTM A234 WPx series buttweld fittings (WP5, WP9, WP91) and A182 Fx

forged fittings and flanges (A182 F5, F9, F11, F22, F91). All these materials have similar chemical and mechanical

properties and can be joined or welded.

Alloying elements

The addition of Molybdenum (“Moly”) increases the strength of the steel and its elastic limit, enhance

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.