ASTM A335 P92 High pressure boiler pipes

Description

ASTM A335 P92 is the part of ASTM A335, The pipe shall be suitable for bending, flanging, and similar forming operations, and for fusion welding. The steel material shall conform to chemical composition, tensile property, and hardness requirements.

• Outer Dimensions: 19.05mm – 114.3mm
• Wall Thickness: 2.0mm – 14 mm
• Length: max 16000mm

Steel grade: ASTM A335 P92

ASTM A335 P92 high pressure semaless boiler pipe, The range of ASTM A335 P92 seamless alloy steel pipe sizes that may be examined by each method shall be subjected to the limitations in the scope of the respective practice.

Each length of pipe shall be subjected to the hydrostatic test. Also, each pipe shall be examined by a non-destructive examination method in accordance to the required practices.

The range of ASTM A335 P92 pipe sizes that may be examined by each method shall be subjected to the limitations in the scope of the respective practice.

The different mechanical test requirements for pipes, namely, transverse or longitudinal tension test, flattening test, and hardness or bend test are presented.Both ends of each crate will indicate the order no., heat no., dimensions, weight and bundles or as requested.

Steel grade: ASTM A335 P91

Chemical Composition(%) ASTM A335

ASTM Specification pipe confirming to ASTM A335 shall have the following chemical properties. Tensile and Hardness Requirements The tensile properties of the ASTM A335 pipe shall conform to the requirements as prescribed. Pipe of Grades P91, P92, and P122 shall have a hardness not exceeding 250 HB/265 HV [25 HRC]. For pipe of Grades P91, P92, P122, and P911, Brinell, Vickers, or Rockwell hardness tests shall be made on a specimen from each lot (see Note 7). These pipe bear high resistance to rupture at high temperature and pressures. With hydrogen crack resistance and sulfide stress corrosion cracking chrome moly pipe are highly preferred over Carbon pipe.

Grade	UN	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	0.5	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	0.5	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	0.5	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	0.5	2.65~3.35	0.80~1.60
P22	K21590	0.05~0.15	0.30~0.60	0.025	0.025	0.5	1.90~2.60	0.87~1.13
P91	K91560	0.08~0.12	0.30~0.60	0.02	0.01	0.20~0.50	8.00~9.50	0.85~1.05
P92	K92460	0.07~0.13	0.30~0.60	0.02	0.01	0.5	8.50~9.50	0.30~0.60

Chrome Moly Pipes: Werkstoff vs EN vs ASTM

ASTM A335 pipe may be either hot finished or cold drawn with the finishing treatment as required in Grade P2 and P12 – The steel shall be made by coarse- grain melting practice. Specific limits, if any, on grain size or deoxidation practice shall be a matter of agreement between the manufacturer and purchaser.

Werkstoff /DIN	EN	ASTM
1.5415	16Mo3	A335 Grade P1
1.7335	13CrMo4-5	A335 Grade P11, P12
1.738	10CrMo9-10	A335 Grade P22
1.7362	X11CrMo5	A335 Grade P5
		A335 Grade P9
1.4903	X10CrMoVNb9-1	A335 Grade P91

Tensile Requirements

Tensile Strength, min., psi	P-5	P-9	P-11	P-22	P-91
ksi	60	60	60	60	85
MPa	415	415	415	415	585
Yield Strength, min., psi
ksi	30	30	30	30	60
MPa	205	205	205	205	415

Product Analysis At the request of the purchaser, an analysis of two pipe from each lot shall be made by the manufacturer. A lot of ASTM A335 pipe shall consist of the following: NPS Designator Under 2 400 or fraction thereof 2 to 5 200 or fraction thereof 6 and over 100 or fraction thereof.
Note: ASTM A335 P91 shall not have a hardness not exceeding 250 HB/265 HV [25HRC].

Mechanical properties of ASTM A335

Grade	Tensile strength	Yield strength
P1,P2	380	205
P12	415	220
P23	510	400
P91	585	415
P92,P11	620	440
P122	620	400

A335 is often called chrome moly pipe because of the chemical makeup of Molybdenum (Mo) and Chromium (Cr). Molybdenum increases the strength of steel as well as the elastic limit, resistance to wear, impact qualities, and hardenability. Moly increases the resistance to softening, restrains grain growth and makes chromium steel less susceptible to embrittlement. Moly is the most effective single additive that increases high temperature creep strength.

It also enhances the corrosion resistance of steel, and inhibits pitting. Chromium (or chrome) is the essential constituent of stainless steel. Any steel with 12% or more Chrome is considered stainless. Chrome is virtually irreplaceable in resisting oxidation at elevated temperatures. Chrome raises the tensile, yield, and hardness at room temperatures. The composition chrome moly alloy steel pipe make it ideal for use in power plants, refineries, petro chemical plants, and oil field services where fluids and gases are transported at extremely high temperatures and pressures.

Heat Treatment Requirements

Grade	Heat Treatment Type P5, P9, P11, and P22	Normalizing Temperature Range F [C]	Subcritical Annealing or Tempering Temperature Range F [C]
A335 P5 (b,c)	Full or Isothermal Anneal
	Normalize and Temper	*****	1250 [675]
	Subcritical Anneal (P5c only)	*****	1325 – 1375 [715 - 745]
A335 P9	Full or Isothermal Anneal
	Normalize and Temper	*****	1250 [675]
A335 P11	Full or Isothermal Anneal
	Normalize and Temper	*****	1200 [650]
A335 P22	Full or Isothermal Anneal
	Normalize and Temper	*****	1250 [675]
A335 P91	Normalize and Temper	1900-1975 [1040 - 1080]	1350-1470 [730 - 800]
	Quench and Temper	1900-1975 [1040 - 1080]	1350-1470 [730 - 800]

Each length of pipe shall be subjected to the hydrostatic test. Also, each pipe shall be examined by a non-destructive examination method in accordance to the required practices.

The different mechanical test requirements for pipes, namely, transverse or longitudinal tension test, flattening test, and hardness or bend test are presented.Both ends of each crate will indicate the order no., heat no., dimensions, weight and bundles or as requested.

Material & Manufacture

Pipe may be either hot finished or cold drawn with the finishing heat treatment noted below.

Heat Treatment

• A / N+T
• N+T / Q+T
• N+T

Mechanical Tests Specified

• Transverse or Longitudinal Tension Test and Flattening Test, Hardness Test, or Bend Test
• For material heat treated in a batch-type furnace, tests shall be made on 5% of the pipe from each treated lot. For small lots, at least one pipe shall be tested.
• For material heat treated by the continuous process, tests shall be made on a sufficient number of pipe to constitute 5% of the lot, but in no case less than 2 pipe.

Notes for Bend Test:

• For pipe whose diameter exceeds NPS 25 and whose diameter to wall thickness ratio is 7.0 or less shall be subjected to the bend test instead of the flattening test.
• Other pipe whose diameter equals or exceeds NPS 10 may be given the bend test in place of the flattening test subject to the approval of the purchaser.
• The bend test specimens shall be bent at room temperature through 180 without cracking on the outside of the bent portion.

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Which is more suitable for components of power plants, P91 or P92 steel?

P91 and P92 steels are the commonly used grades according to ASTM A335 or SA335, which are used for pipelines and power unit components due to their high strength properties at elevated temperatures. What’s the difference between P91 and P92 steel?

 

1.P92 steel is a new type of steel developed by adding W elements on the basis of P91 steel and appropriately reducing the content of element Mo. P91 and P92 Steel Chemical composition comparison showed below:(%)

Grade	C	Si max	Mn	P	S	Ni max	Cr	Mo	W
P91	0.08-0.12	0.50	0.30-0.60	0.02	0.01	0.4	8.0-9.5	0.85-1.05	/
P92	0.07-0.13	0.50	0.30-0.60	0.02	0.01	0.4	8.5-9.5	0.30-0.60	1.90

2.They all have good physical properties.The thermal conductivity of P92 is the same as that of P91 steel and higher than Austenitic steel.The linear expansion coefficient of P92 steel is the same as P91 steel,but lower than Austenitic steel. So when the unit starts and stops, ability to resist fatigue damage of P92 steel is better than that of Austenitic steel and steel P22.

3.P92 has higher temperature creep rupture strength than P91 steel.

The temperature and strength of P92 steel are higher than that of P91 steel.According to ASME standards at 550 ℃, 600 ℃ and 625 ℃, 100000 hours of P92 steel under different temperature creep rupture strength of 199 mpa and 131 mpa and 101 mpa, respectively;The creep rupture strength of P91 steel at corresponding temperature is 141MPa, 98MPa and 68MPa.

4.P92 has excellent room temperature impact toughness.

P92 steel has higher temperature performance and excellent temperature and toughness than traditional steel. It’s roughly the same as P91.

5.Both of them are excellent in oxidation resistance.

The anti-soot oxidation and anti-water vapor oxidation of P92 steel are approximately the same as that of P91 steel.After the test, P92 steel and P91 steel under 600 ℃, 700 ℃, 600 hours of steam oxide coating thickness is roughly the same.

Both of them are especially suited for steam boiler, boiler parts, boiler drum,pressure vessel for the apparatus Engineering and similar purposes. Modern power engineering technologies and power unit structures, especially those working at supercritical parameters, require the P91 and P92 steels which exhibit high creep resistance. In fatigue test conditions, the P91 steel has exhibited higher low-cycle life.

Therefore, considering the factor of possible interaction of loads, variable in time, the behaviour of both steels should be taken into account the interdependence of creep and fatigue. It is impossible to decide which of them is more suitable for work as a material of components of power plants.