Alloy Seamless Pipe

High temperature alloy steel tubes are known as chrome moly pipe.

ASTM A213, A209 specification covers alloy steel seamless tube for high temperature service. Seamless alloy steel tubes are suitable for bending and similar forming operations, and for fusion welding at high temperatures. High temperature alloy steel tube are also considered as low alloy chrome moly grades.

ASTM/ASME A/SA213 Gr. T2, T11, T12, T22, T91, T92

ASTM/ASME A/SA335 Gr. P1, P2, P5, P11, P12, P22

ASTM/ASME A/SA209 T1, T1a, T1b

ASTM A213 tubing has been widely used in high temperature services especially for the boiler and superheater. Tube material could be in alloy steel and stainless steel, and manufactured in seamless of hot rolled or cold drawn. Common grades are T9, T11, T12, T21, T22, T91 and stainless grades in TP304 or TP316.

The A335 pipes are generally called chrome moly pipe, it is a type of seamless pipe could be used in high temperature environments of 540 – 750 °C, they have a high level of Chromium and Molybdenum presence in it, While Molybdenum increases the overall strength, resistance, elasticity, hardenability and overall quality, moly ensures that the material is more resistant to softening, restrains the growth of grains and lessens the chances of embrittlement. It is the single additive that is responsible for the increase in high temperature resistance and it also improves the corrosion resistance to steel.

This chrome moly pipe featured grades are ASTM A335 P9, P11, P22, P91, so also it could be called as P Grade pipe in some cases.
P11 pipe, P22 pipe and P91 pipes are used in power industry and petro-chemical plants, meanwhile, P5 and P9 pipe generally find usage in refineries.
ASTM A209 / A209M, ASME SA209 T1, T1a, T1b is the standard applicable to seamless carbon-Molybdenum Alloy-Steel Boiler and Superheater Tubes.

Size of Alloy Seamless Steel Pipe:
OD:6-720MM
WT:0.5-120MM
Length:3-16M
 
Seamless Alloy Steel Tube Application:
1. Construction hall structure, sea trestle, airport structure, shipbuilding, security door frames, garage doors, strengthening liners of steel doors and windows, indoor partition walls, cable bridge structures and expressway safety guards, balustrade, decorating, residential, ornamental pipes.
2. Agriculture: Agricultural equipment.
3. Industry machinery,  solar stent, offshore oil field, mine equipment, electromechanical hardware, heavy engineering, mining and resources, process engineering, materials handling,mechanical parts.
4. Traffic walking rails, roll-up doors, guardrail, plaza structure, signage, road furniture, fencing logistics storage supermarket shelves, containers, transport industries, commercial construction other sports apparatus, leisure equipment, furniture, school furniture.

5. Material storage racks, pallets, hydraulic platforms, trusses, columns, purlins, greenhouse stands towers.

Standard of Alloy Seamless Steel Tube

A335	Standard Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service
A213	Standard Specification for Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes
A209	Standard Specification for Seamless Carbon-Molybdenum Alloy-Steel Boiler and Super heater Tubes

Outside Diameter & Tolerance of Alloy Seamless Steel Pipe

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, mm	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%

Wall thickness & Tolerance of Alloy Seamless Steel Pipe

ASTM A450	Hot rolled	Outside Diameter, mm	Tolerance, %
		OD≤101.6, WT≤2.4	+40/-0
		OD≤101.6, 2.4＜WT≤3.8	+35/-0
		OD≤101.6, 3.8＜WT≤4.6	+33/-0
		OD≤101.6, WT>4.6	+28/-0
		OD>101.6, 2.4＜WT≤3.8	+35/-0
		OD>101.6, 3.8＜WT≤4.6	+33/-0
		OD>101.6, WT>4.6	+28/-0
	Cold Drawn	Outside Diameter, mm	Tolerance, %
		OD≤38.1	+20/-0
		OD>38.1	+22/-0
ASTM A530	NPS	Outside Diameter, mm	Tolerance, %
		1/8≤OD≤2-1/2	+20.0/-12.5
		3≤OD≤18, WT/OD≤5%	+22.5/-12.5
		3≤OD≤18, WT/OD>5%	+15.0/-12.5
		OD≥20, WT/OD≤5%	+22.5/-12.5
		OD≥20, WT/OD>5%	+15.0/-12.5

Length: 5800mm; 6000mm; 6096mm; 11800mm; 12000mm; and so on.
Max length: 16000mm

Keyword: High Pressure Steel Pipe, Boiler Steel Pipe, ASME SA335, P11, ASTM A335

ASTM ASME (S)A-335/(S)A-335M Grade and Chemical Composition

Chemical Composition of Alloy Seamless Steel Pipe

C, %	Mn, %	P, %	S, %	Si, %	Cr, %	Mo, %
0.05-0.15	0.30-0.60	0.025 max	0.025 max	0.50-1.00	1.00-1.50	0.44-0.65

Mechanical Properties of Alloy Seamless Steel Pipe

Tensile Strength, MPa	Yield Strength, MPa	Elongation, %
415 min	205 min	30 min

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

Painting & Coating of Alloy Seamless Steel Pipe: Oiled or Black painted to prevent rust

A: Seamless pipes are made from a solid billet and have no weld seam, making them theoretically stronger in high-pressure applications. However, modern welding technologies (like SAW) have made alloy welded pipes equally reliable for many high-pressure and high-temperature applications. Welded pipes are generally more cost-effective, especially in larger diameters, and offer better dimensional consistency in wall thickness.

A: Yes, absolutely. Our alloy welded pipes, particularly those conforming to ASTM A691 (e.g., Grade 2 1/4CR, 5CR, 9CR), are specifically designed for high-temperature and high-pressure service. They offer excellent creep resistance and oxidation resistance, making them suitable for power plant piping and refineries.

A: We perform comprehensive testing to ensure quality. This includes Chemical Composition Analysis, Mechanical Property Testing (Tensile, Yield, Elongation), Hydrostatic Testing, and Non-Destructive Testing (NDT) such as Ultrasonic Testing (UT), Radiographic Testing (RT), and Dye Penetrant Testing (PT). We can also provide Impact Testing for low-temperature applications.

A: The delivery time depends on the quantity and specifications of the order. Generally, for standard alloy grades and sizes, the lead time is approximately 30 to 45 days after receiving the deposit. Custom sizes or specific heat treatment requirements may take slightly longer.

A: Yes, we can provide samples for evaluation purposes. However, depending on the alloy grade (which can be expensive due to raw material costs like Molybdenum and Chromium), there may be a charge for the sample and freight, which can be deducted from the final order value.