Carbon Steel Seamless Steel Pipe Api ASTM A355 P5 P5b P5c

Place of Origin Jiangsu,China
Certification ISO 9001 ,CE
Minimum Order Quantity 1 PCS
Delivery Time 7~10 working days
Payment Terms L/C, T/T, Western Union
Supply Ability 5000 Ton/Tons per Month
Product Details
Product Name Alloy Steel Pipe Standard ASTM,ASME,API
Type Hot Rolled,Cold Drawn,NPS Pipe End Plain End,Beveled End,Treaded
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Product Description

ASTM A355 Grade P5/P5b/P5c Seamless Alloy Steel Pipe 

ALLOY pipe

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.



Standard Low-Alloy Steel Grade

P1     P2     P5     P5b     P5c     P9     P11     P12     P15     P21

P22   P91   P92




ASTM A335 P5 Pipe comes under the ASTM 335 specification with 1/8NB to 24B sizes. The outer dimensions range from 19.05mm to 114mm. This is a larger diameter pipe specification.



Element C Mn Si P S Cr Mo
P1 0.10~0.20% 0.30~0.80% 0.10~0.50% 0.025% 0.025% - 0.44~0.65%
P2 0.10~0.20% 0.30~0.61% 0.10~0.30% 0.025% 0.025% 0.50~0.81% 0.44~0.65%
P5 0.15% 0.30~0.60% 0.50% 0.025% 0.025% 4.0~6.0% 0.44~0.65%
P5b 0.15% 0.30~0.60% 1.00~2.00% 0.025% 0.025% 4.0~6.0% 0.44~0.65%
P5c 0.12% 0.30~0.60% 0.50% 0.025% 0.025% 4.0~6.0% 0.44~0.65%
P9 0.15% 0.30~0.60% 0.50~0.10% 0.025% 0.025% 8.0~10.0% 0.44~0.65%
P11 0.05~0.15% 0.30~0.61% 0.50~0.10% 0.025% 0.025% 1.0~1.5% 0.44~0.65%
P12 0.05~0.15% 0.30~0.60% 0.50% 0.025% 0.025% 0.8~1.25% 0.44~0.65%
P15 0.05~0.15% 0.30~0.60% 1.15~1.65% 0.025% 0.025% - 0.44~0.65%
P21 0.05~0.15% 0.30~0.60% 0.50% 0.025% 0.025% 2.65~3.35% 0.80~1.60%
P22 0.05~0.15% 0.30~0.60% 0.50% 0.025% 0.025% 1.9~2.6% 0.87~1.13%
P91 0.08~0.12% 0.30~0.60% 0.20~0.50% 0.02% 0.01% 8.0~9.0% 0.85~1.05%
P92 0.07~0.13% 0.30~0.60% 0.50% 0.02% 0.01% 8.5~9.5% 0.30~0.60%




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:

  • Aluminum: decreases oxygen from steelmaking
  • Boron: used to produce fine grain size and enhance steel hardness
  • Cobalt: used to enhance the steel’s heat and wear-resistance
  • Manganese: gives better steel hardenability
  • Nickel: Enhances toughness, hardenability and impact strength at low temperatures
  • Silicon: decreases oxygen, enhances hardenability and toughness
  • Titanium: prevents precipitation of chromium carbide
  • Tungsten: refines steel grain size and enhance the steel hardness, especially at high temperatures
  • 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.