ASTM A335 P91 Alloy Steel Seamless Pipes

P91 Alloy Steel Seamless Pipes

Trio Steel manufactures and exports P91 alloy steel seamless pipes built for extreme temperature and pressure environments. Engineers trust this grade because it delivers high strength without sacrificing weldability. We supply ASTM A335 P91 pipes with full mill test certification, so every batch meets international quality standards before it reaches your site.

What Makes P91 Alloy Steel Seamless Pipes Different

P91 alloy steel seamless pipes belong to the chrome-moly family, containing 8% to 9.5% chromium and roughly 1% molybdenum. This composition gives the material excellent creep strength and long-term stability under sustained heat. Unlike older grades such as P22 or P9, P91 pipes handle temperatures up to 600°C while using thinner wall sections. That reduction in thickness lowers material costs and improves thermal efficiency across the system.

Chemical and Mechanical Properties

Our P91 alloy steel seamless pipes meet strict compositional limits, including controlled vanadium, nitrogen, and niobium content for enhanced strength. Each pipe carries a minimum tensile strength of 585 MPa and a minimum yield strength of 415 MPa, outperforming conventional carbon steel pipes by a wide margin. We manufacture through a controlled heat treatment process, normalizing at 1050°C and tempering at 760°C. This process stabilizes the microstructure and ensures consistent performance under cyclic thermal stress.

Applications of P91 Alloy Steel Seamless Pipes

Power plants, refineries, and petrochemical facilities rely on P91 alloy steel seamless pipes for steam lines, boiler systems, and heat exchangers. The material performs especially well in combined-cycle power plants and Heat Recovery Steam Generators, where thermal efficiency and coil placement matter most. Engineering firms, government contractors, and industrial fabricators across the globe specify this grade whenever high-pressure, high-temperature transport is essential.

Why Source P91 Alloy Steel Seamless Pipes from Trio Steel

We deliver P91 alloy steel seamless pipes with full traceability, supported by Mill Test Certificates as per EN 10204 3.1/3.2. Our team works closely with clients to match specifications precisely, from wall thickness to length requirements. We maintain updated equipment and strict quality control at every production stage, so you receive pipes that perform reliably under demanding service conditions. Whether you need single random lengths or custom-cut pipes, we tailor each order to your project timeline.

ASTM A335 P91 Alloy steel Seamless Pipes Specifications

ALLOY STEEL
STANDARDS	SEAMLESS PIPE
ASTM	A 335
ASME	SA 335

TEST CERTIFICATE / MILL CERTIFICATE

We can provide A335 P91 Alloy steel Seamless Pipe Mill Test Certificate as per EN 10204 as per 3.1/3.2 TC

Chemical Composition

C, %	Mn, %	P, %	S, %	Si, %	Cr, %	Mo, %	V, %	N, %	Ni, %	Al, %	Nb, %
0.08-0.12	0.3-0.6	0.02 max	0.01 max	0.2-0.5	8.0-9.5	0.85-1.05	0.18-0.25	0.03-0.07	0.4 max	0.04 max	0.06-0.10

Mechanical Properties

Tensile Strength, MPa	Yield Strength, MPa	Elongation, %	Hardness, HB
585 min	415 min	20 min	250 max

Outside Diameter & Tolerance

ASTM A450	Hot rolled	Outside Diameter, mm	Tolerance, mm
		OD≤101.6	+0.4/-0.8
		101.6＜OD≤190.5	+0.4/-1.2
		190.5＜OD≤228.6	+0.4/-1.6
	Cold Drawn	Outside Diameter, mm	Tolerance, mm
		OD＜25.4	±0.10
		25.4≤OD≤38.1	±0.15
		38.1＜OD＜50.8	±0.20
		50.8≤OD＜63.5	±0.25
		63.5≤OD＜76.2	±0.30
		76.2≤OD≤101.6	±0.38
		101.6＜OD≤190.5	+0.38/-0.64
		190.5＜OD≤228.6	+0.38/-1.14
ASTM A530 & ASTM A335	NPS	Outside Diameter, inch	Tolerance, mm
		1/8≤OD≤1-1/2	±0.40
		1-1/2＜OD≤4	±0.79
		4＜OD≤8	+1.59/-0.79
		8＜OD≤12	+2.38/-0.79
		OD>12	±1%

ASTM ASME (S)A-335/(S)A-335M Grade and chemical composition

Grade	UNS	C≤	Mn	P≤	S≤	Si≤	Cr	Mo
P1	K11522	0.10~0.20	0.30~0.80	0.025	0.025	0.10~0.50	–	0.44~0.65
P2	K11547	0.10~0.20	0.30~0.61	0.025	0.025	0.10~0.30	0.50~0.81	0.44~0.65
P5	K41545	0.15	0.30~0.60	0.025	0.025	0.50	4.00~6.00	0.44~0.65
P5b	K51545	0.15	0.30~0.60	0.025	0.025	1.00~2.00	4.00~6.00	0.44~0.65
P5c	K41245	0.12	0.30~0.60	0.025	0.025	0.50	4.00~6.00	0.44~0.65
P9	S50400	0.15	0.30~0.60	0.025	0.025	0.50~1.00	8.00~10.00	0.44~0.65
P11	K11597	0.05~0.15	0.30~0.61	0.025	0.025	0.50~1.00	1.00~1.50	0.44~0.65
P12	K11562	0.05~0.15	0.30~0.60	0.025	0.025	0.50	0.80~1.25	0.44~0.65
P15	K11578	0.05~0.15	0.30~0.60	0.025	0.025	1.15~1.65	–	0.44~0.65
P21	K31545	0.05~0.15	0.30~0.60	0.025	0.025	0.50	2.65~3.35	0.80~1.60
P22	K21590	0.05~0.15	0.30~0.60	0.025	0.025	0.50	1.90~2.60	0.87~1.13
P91	K91560	0.08~0.12	0.30~0.60	0.020	0.010	0.20~0.50	8.00~9.50	0.85~1.05
P92	K92460	0.07~0.13	0.30~0.60	0.020	0.010	0.50	8.50~9.50	0.30~0.60

Note:

(S)A335 P91 other chemical composition are : V 0.18~0.25; N 0.030~0.070; Ni ≤ 0.40; Al ≤ 0.04 ; Nb 0.06~0.10
(S)A335 P92 other chemical composition are : V 0.15~0.25; N 0.030~0.070; Ni ≤ 0.40; Al ≤ 0.04 ; Nb 0.04~0.09; W 1.5~2.00 ; B 0.001~0.006

ASTM A335 P91 Alloy steel Seamless Pipes Application

At Trio Steel, we proudly provide quality ASTM A335 P1 Alloy steel Seamless Pipes to the following industries:

Chemical
Petrochemical
Refineries
Fertilizers
Power Plant
Nuclear Power
Oil Mills
Mining
Construction
Shipbuilding
Steel Plant

Offshore
Oil & Gas
Paper
Breweries
Cement
Sugar
Defence
Ports
Railway
Engineering Co. &
Government Org.

Heat Treatment Requirements

	P5, P9, P11, and P22
Grade	Heat Treatment Type	Normalizing Temperature Range F [C]	Subcritical Annealing or Tempering Temperature Range F [C]
	Heat Treatment Type	Normalizing Temperature Range F [C]
P5 (b,c)	Full or Isothermal Anneal
	Normalize and Temper	*****	1250 [675]
	Subcritical Anneal (P5c only)	*****	1325 – 1375 [715 – 745]
P9	Full or Isothermal Anneal
	Normalize and Temper	*****	1250 [675]
P11	Full or Isothermal Anneal
	Normalize and Temper	*****	1200 [650]
P22	Full or Isothermal Anneal
	Normalize and Temper	*****	1250 [675]
P91	Normalize and Temper	1900-1975 [1040 – 1080]	1350-1470 [730 – 800]
	Quench and Temper	1900-1975 [1040 – 1080]	1350-1470 [730 – 800]

ASTM A335 P91 Alloy steel Seamless Pipes Packaging & Delivery

ASTM A335 P1 Alloy steel Seamless Pipes Packaging

ASTM A335 P91 Alloy steel Seamless Pipes Packaging at Trio Steel Factory

Packaging Details:

There are probably hundreds of different methods for packing a pipe, and most of them have merit, but there are two principles that are vital for any method to work prevent rusting and Sea transportation security. Our ASTM A335 P91 Alloy steel Seamless Pipes packing can meet any needs of the customers.

ASTM A335 P91 Alloy steel Seamless Pipes Bundle packing ASTM A335 P1 Alloy steel Seamless Pipes Crate packing ASTM A335 P91 Alloy steel Seamless Pipes Naked packing ASTM A335 P91 Alloy steel Seamless Pipes Protect by wood at both ends

Delivery Detail:

7-15 days

Get a Quote for P91 Alloy Steel Seamless Pipes

Contact our team today to discuss specifications, pricing, and delivery timelines for your next project. We export P91 alloy steel seamless pipes worldwide and provide dedicated support from inquiry through delivery.

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