Why is there such a high demand for ASTM A335 pipe in these specific industries? How familiar are you with this type of pipe? What are the most prominent grades within this standard?

The following article will tell you all the things you need to know about this pipe.

Listed topics
What is ASTM A335 pipe
Standard specification
Featured Grades
Referred standards to manufacture this pipe
Raw steel material that used for the production
Tests involved
Things you need to notice when placing an order

What is ASTM A335 pipe?

ASTM A335 pipe, also known as ASME S/A335 Chrome-Moly pipe, is a type of seamless pipe that is specifically designed for high-temperature environments. It can withstand temperatures ranging from 540 to 750 °C.

A335 pipes are commonly referred to as chrome moly pipes due to their high content of Chromium and Molybdenum. The presence of Molybdenum enhances the strength, resistance, elasticity, hardenability, and overall quality of the pipe. It also improves the high temperature resistance and corrosion resistance of the steel. Molybdenum plays a crucial role in preventing softening, limiting grain growth, and reducing the risk of embrittlement.

Key Elements Chromium for this pipe

Chromium is an essential element in the production of stainless steel. When the chromium content exceeds 12%, the material can be classified as stainless steel. Chromium provides excellent resistance to oxidation, even at elevated temperatures. It also improves the hardness, tensile strength, and yield strength of the material at standard temperatures. The composition of chrome-moly pipes makes them ideal for use in power plants, refineries, petrochemical plants, and other oil field services where transportation under high temperatures and pressures is involved.

ASTM A335 Standard Specification and Scope

According to ASTM International, ASTM A335 is the standard specification for seamless Ferritic Alloy-Steel Pipe for High Temperature Service. This specification covers pipes with alloy material, manufactured in seamless form, and with nominal wall and minimum wall thickness. The pipes specified under this standard are suitable for bending, flanging, and other similar processing and formations. Additionally, they are also suitable for fusion welding.

Therefore, ASTM A335 pipe material can also be used in the manufacturing of pipe fittings such as elbows, tees, reducers, and so on.

A335 P5, P9, P11, P22, P91 Pipe Chemical Composition

ASTM A335 Pipe Mechanical Properties

Referred standards ASTM

a. ASTM A999/ A999M, Standard specification for common requirements for stainless and alloy steel pipe
b. ASTM A92, Hardness test methods for steel materials
c. E213, Instructions and practice for ultra sonic testing of steel pipe and tube
d. E309 Eddy-Current Examination methods for steel pipe products
e, E381, Inspection methods for steel bars, beams, profiles, billets and forgings.
f, E527, Numbering metals and alloys practices
g, E570, Instructions for flux leakage examination of ferromagnetic steel pipe products

Nominal Pipe Size

ASME B36.10M dimensions standard for welded and seamless steel pipe

Raw steel material that used for the production

The pipe material can be either hot finished or cold drawn, and the related heat treatment is required for different grades. For Grade P2 and P12, the steel should be manufactured using coarse-grain melting procedures.

Featured Grades P5, P9, P11, P22, P91 pipes

These chrome moly pipes are available in different grades, namely ASTM A335 P9, P11, P22, and P91. In some cases, they may also be referred to as P Grade pipes.

P11, P22, and P91 pipes are commonly used in the power industry and petrochemical plants, while P5 and P9 pipes are typically used in refineries.

ASTM A335 P91 pipes – High Pressure Boiler Pipes

It is important to note that ASTM A335 Grade P91 pipe is a high-grade pipe that is commonly used for high-pressure boilers. P91 pipe is particularly suitable for bending, flanging, and similar operations, including welding. The steel material must adhere to specific chemical composition, tensile properties, and hardness requirements.

There are two variants available: ASTM A335 P91 alloy steel pipe and high-pressure boiler pipes. The range of these pipes is dependent on their size, which is determined by their specific usage. The length of the pipe will be subject to a hydrostatic test, and there will also be a non-destructive examination performed in accordance with the specifications.

As a result, chrome moly pipe is widely used in the power generation and petrochemical industries due to its corrosion resistance, high tensile strength, and ability to withstand high temperatures. This makes it a cost-effective choice for these industries.

Tests involved

Some of the common tests conducted include transverse and longitudinal tension tests, flattening tests, hardness tests, and bend tests. In the case of a material heat test conducted in a blast furnace, it will be performed on 5% of the pipes manufactured from each lot.

If the diameter of the pipe exceeds NPS 25, the diameter to wall thickness ratio should typically be 7.0 or less. For NPS 10 and thicker pipes, the flattening test is only conducted with the approval of the purchaser.

Things you need to notice when placing an order

When sending an inquiry or placing an order for ASTM A335 pipe, the following specifications should be verified:

a. Length per piece and the quantity (Specified in feet, meters or pieces)
b. Material Name (Seamless alloy steel pipe)
c. Grade (P5, P9, P11, P22, P91 pipe etc)
d. Manufacturing types (hot finished seamless or cold drawn seamless)
e. Size to described as below ways:
1. NPS and Schedule Number (According to ASME B36.10, for example NPS 7 inch and Sch 40)
2. OD or ID and nominal or minimum wall thickness (inch or mm)

API 650 standard applies only to tanks whose entire bottom is uniformly supported and to tanks in non-refrigerated service that have a maximum design temperature of 93℃ (200℉) or less.

Why API 650 storage tanks so important in oil and gas industry

Generally the main requirement of the oil and petroleum industry is the tank that is required to store the products safe and securely. The safety is very important while storing these types of products as they any carelessness can lead to fatalities.

Therefore, the material used for erecting the oil and gas storage tanks has to follow strict guidelines to ensure safety. These tanks have to follow the American Petroleum Institute’s (API) standards that focus on theupdated policies, and design requirements. They are manufactured from materials like carbon steel and stainless steel that adheres to

• The design standards
• The fabrication guidelines
• Rigorous testing
• Right stamping of the tanks

Guidelines to Get the Best Natural Oil and Gas Storage Tanks

The Octal steel design the oil and gas storage tanks that adheres to all these policies that will suit the customer’s requirements precisely.The designs are customized to meet the specifications of the fabrication and erection of tanks that will help in meeting the API standards. These ensure that
• The safety of industry operation is enhanced
• The quality of the product is assures quality
• It assists in keeping the costs down
• It helps reduce waste
• The confusion is minimized

Standards and Materials that Used for Natural Oil Storage Tanks

By following these guidelines the product will get a speedy acceptance and brought to the market quickly. There are the most common types that are available for erecting the tanks, which is selected based on the requirements are namely

• API 650 used for carbon, aluminum and stainless steel tanks
• API 620 used for large steel tanks that is low on pressure

What is API 650

The API 650 is the standards specification guidelines that the American Petroleum Industry insists on the welded tanks used for storage. These specifications guidelines are strictly followed to check the design of the Natural oil and gas storage tank, its fabrication, welding performed, the inspection done on it, and the requirements for erecting it. It is designed specially to withstand products that have internal pressures 2.5 PSI (Pounds per Square Inch) or less.

Sensible Amenities to Optimum Safety

The positives of using an API 650 natural oil storage tanks include
• These tanks can store products like crudeoil, gasoline, chemical, water and biofuel so it is most widely used tanks in the oil industry.
• The API 650 ensured tanks can store contents at a very low pressure (maximum of 2 ½ PSI) that is much higher than API 620. It also stores products at a very higher temperature that ranges between -40 degrees Fahrenheit to 500 degrees Fahrenheit.
• This is generally used for refineries, terminals, and pipeline facilities.
• It can be made in any size that depends on the requirements of the customers.

The Octal steel provides its customer the quality products that will ensure durability with maximum versatility with designs and fabricates that follow the guidelines precisely. The API 650 storage tanks are safe and quite economical to the customers. As oil and gas are the heart of any country’s growth, its safety is the most important point to concentrate that will confirm that no negligence is triggered that will lead to destruction of human life and properties. A trusted company will provide quality products with very good customer service that will result in good gains for the customer.

Our Supply Range for API 5L Pipe

Grades: API 5L Grade B, X42, X52, X56, X60, X65, X70, X80
Product Specification Level: PSL1, PSL2, onshore and offshore sour services
Outer Diameter Range: 1/2” to 2”, 3”, 4”, 6”, 8”, 10”, 12”, 16 inches, 18 inches, 20 inches, 24 inches up to 40 inches.
Thickness Schedule: SCH 10. SCH 20, SCH 40, SCH STD, SCH 80, SCH XS, to SCH 160
Manufacturing Types: Seamless (Hot Rolled and Cold Rolled), Welded ERW (Electric resistance welded), SAW (Submerged Arc Welded) in LSAW, DSAW, SSAW, HSAW
Ends Type: Beveled ends, Plain ends
Length Range: SRL (Single Random Length), DRL (Double Random Length), 20 FT (6 meters), 40FT (12 meters) or, customized
Protection Caps in plastic or iron
Surface Treatment: Natural, Varnished, Black Painting, FBE, 3PE (3LPE), 3PP, CWC (Concrete Weight Coated) CRA Clad or Lined

Here we will do a brief introduction of API 5L pipe and related standard specifications with the below aspects:
Standard Scope
Manufacturing types
Different Grades (B, X42, X46, X52, X60, X65, X70)
Delivery condition (R, N, Q, M)
Product Specification Level (PSL1 and PSL2)
Material specifications (Chemical and Mechanical)
Test Methods
Tolerances on pipe diameters, wall thickness, out-of-roundness
Common defects
Line pipe history and milestones
Applications

API 5L Pipe Standard Scope

In API SPEC 5L 46th Edition, the standard scope is defined as: “Requirements for the manufacture of two product specification levels (PSL1 and PSL2) of seamless and welded steel pipes for use in pipeline transportation systems in the petroleum and natural gas industries. This standard does not apply to cast pipe.”

To summarize, API 5L pipe is the carbon steel pipe applied to the oil and gas transmission system. Meanwhile, other fluids such as steam, water, and slurry can also adopt the API 5L standard for their transmission purposes.

Different Manufacturing Types

API 5L specification covers the manufacturing types in welded and seamless.

Welded Type: ERW, SAW, DSAW, LSAW, SSAW, HSAW Pipe

The API 5L welded pipe common types are as follows:

ERW: Electric Resistance Welded, for pipe diameter normally under 24 inches.

DSAW/SAW: Double Submerged Arc Welding / Submerged Arc Welding, a substitute welding method of ERW for larger diameter pipes.

LSAW: Longitudinal SAW, for diameter up to 48 inches. Also called the JCOE manufacturing process.

SSAW/HSAW: Spiral Submerged Arc Welded / Helical SAW, pipe diameters up to 100 inches.

Check here for the differences between the ERW, LSAW, and SSAW pipes.

LSAW Pipe Manufacturing Video

SSAW Manufacturing Video

Seamless Type: Hot Rolled Seamless and Cold Rolled Seamless Pipe

Seamless manufacturing type is usually for small diameter pipes (typically under 24 inches).

(When the pipe diameter is less than 150 mm or 6 inches, the seamless steel pipe is more commonly applied than the welded steel pipe.)

There are also seamless pipes of large diameters. By using hot rolled manufacturing process, we can get seamless pipes with diameters up to almost 20 inches (508 mm). If you need seamless pipes with diameters above 20 inches, we can make them through hot expanding process, with maximum diameters up to 40 inches (1016 mm).

Seamless Pipe Manufacturing Video

API 5L Pipe Manufacturing Development

In the earliest years, besides Seamless and ERW, SAW manufacturing technologies, the API 5L steel pipe also could be produced in furnace lap-welded (deleted in API 5L in 1962).

With the development of pipeline steel plate-making technology, pipe forming and welding technology has also seen significant improvement, so a lot of ERW pipes and SAW pipes have been used in pipeline constructions. When it comes to big-diameter steel pipes, SAW pipe gains a great advantage. With less raw material cost and simplified and uniform production procedures, welded steel pipe has taken the first place in oil and gas line pipe industries.

API 5L covers Grade B, X42, X46, X52, X56, X60, X65, X70, X80

API 5L steel line pipe adopts different steel grades, which are Gr. B, X42, X46, X52, X56, X60, X65, X70, X80. Some manufacturers are capable of manufacturing steel grades up to X100 and X120. As steel line pipes’ grades go higher, they have stricter control on the carbon equivalent control and higher mechanical strength performance.

Moreover, in the same grade, seamless and welded API 5L pipes have different chemical compositions, namely, welded pipes have stricter requirements and lower amounts of carbon and sulfur.

In terms of different delivery conditions, there are also As-rolled, normalizing rolled, thermomechanical rolled, normalizing formed, normalized, normalized and tempered, quenched and tempered.

Delivery Conditions for Each API 5L Grade

more:

For intermediate grades, API 5L pipe grade shall be in one of the following description formats:

a. The letter L followed by the specified minimum yield strength in Mpa. For example, L290 (X42) means the minimum yield strength is 290 Mpa. In the case of PSL2 pipe, Suffix letters (R, N, Q, or M) shall be added to describe the delivery condition;

b. The letter X followed by a two or three digital number equal to the minimum yield strength in 1000 psi rounded down to the nearest integer and, for PSL2 pipe, the letter describing the delivery condition (R, N, Q, or M) consistent with the above formats.

Letter R: As rolled
Letter N: Normalizing rolled, Normalized formed, Normalized
Letter Q: Tempered and quenched
Letter M: Thermomechanical rolled or thermomechanical formed
Letter S: Sour Services, comes with PSL2 pipe for NS, QS, and MS, eg API 5L X52MS, API 5L X65QS.

Product Specification Level (PSL1 and PSL2 in API 5L)

What is PSL

PSL is the abbreviation of product specification level, which includes PSL1 and PSL2. It also could be deemed as quality level.

PSL1 and PSL2 differences

Please click here for the differences between PSL1 and PSL2 pipes.

Requirement

PSL1 and PSL2 have not only different testing requirements but also different chemical composition and mechanical properties.

PSL1 has stricter requirements than PSL2 in terms of chemical composition, tensile properties, impact test, nondestructive testing, and other indicators.

For more details, please click here for Differences between API 5L PSL1 and PSL2.

Impact Test

PSL1 does not require an impact test, while it is required for PSL2 (except X80).

Non-destructive Test

PSL1 does not require a non-destructive test, while it is required for PSL2.

(NDT: Non-destructive inspection and testing uses radiographic, ultrasonic, or other methods (not breaking the material) in API 5L standard, to reveal pipe defects and imperfections.)

API 5L Pipe Data Sheet Specification

API 5L Pipe Data Sheet specification including chemical composition and mechanical properties for PSL1 and PSL2 pipe.

Chemical Composition

Chemical composition for PSL1 line pipe with wall thickness ≤ 25.0 mm (0.984 inches)
API 5L Pipe Datasheet in PDF

API 5L PSL2 Pipe chemical properties:

Chemical Composition for API Sour Pipe

a. If C > 0.12%, CEIIW limits shall be applied; If C ≤ 0.12%, CEPCM shall be applied.
b. For each reduction of 0.01% for maximum C, an increase of 0.05% maximum Mn is permissible, up to a maximum of 0.20%.
c. Al ≤ 0.060%; N ≤ 0.012%; Al/N ≥ 2:1 (titanium-killed or titanium-treated steel not applicable); Cu ≤ 0.35% (Cu ≤ 0.10% if agreed); Ni ≤ 0.30%; Cr ≤ 0.30%; Mo ≤ 0.15%; B ≤ 0.0005%.
d. For seamless and welded pipes, Ca ≤ 0.006%; For welded pipe if Ca is added by intention unless agreed, Ca/S ≥ 1.5 in case S > 0.0015%.
e. For SMLS pipe maximum limit for S could be increased to ≤ 0.008%, and in case welded if agreed to ≤ 0.006%. For higher S content in the welded pipe, lower Ca/S ratios maybe agreed.
f. Nb + V ≤ 0.06%, unless otherwise agreed.
g. Nb + V + Ti ≤ 0.15%.
h. In case seamless pipe, listed CEPCM value could be increased by 0.03.
i. Mo ≤ 0.35% in case agreed.
j. Cr ≤ 0.45% in case agreed.
k. Cr ≤ 0.45% and Ni ≤ 0.50% in case agreed.

Tensile and Yield strength

For intermediate grades, the difference between the specified minimum tensile strength and minimum yield strength for the pipe body shall be as given in the table for the next higher grade. The specified minimum tensile strength for the weld seam shall be the same value as was determined for the pipe body ung footnote a)

a. For intermediate grades, the difference between specified maximum yield strength and minimum YS shall be as given in the table for the next higher grade, and the difference between specified minimum tensile strength and the specified minimum TS shall be as given in the table for the next higher grade. For intermediate grades up to Grade L320 or X46, the tensile strength shall be ≤ 655 MPa (95 000 psi). For intermediate grades greater than Grade L320 or X46 and lower than Grade L555 or X80, the tensile strength shall be ≤ 760 MPa (110 200 psi). For intermediate grades higher than Grade L555 or X80, the maximum permissible tensile strength shall be obtained by interpolation. For SI units, the calculated value shall be rounded to the nearest 5 MPa. For USC units, the calculated value shall be rounded to the nearest 100 psi.
b. For grades > L625 or X90, Rp0,2 applies.
c. Above limit applies for pipe with D > 323,9 mm (12.750 in).
d. For intermediate grades, the specified minimum tensile strength for the weld seam shall be the same value as was determined for the pipe body using footnote a).
e. For pipe requiring longitudinal testing, the maximum yield strength shall be ≤ 495 MPa (71 800 psi).
f. The specified minimum elongation, Af, shall be as determined with following equation:

g. Lower values of Rt0,5/Rm may be specified by agreement.
h. For grades > L625 or X90, Rp0,2 /Rm applies. Lower values of Rp0,2 /Rm may be specified by agreement.

Mechanical Properties for API 5L Sour Service Pipe

The strength value is the same as PSL2.

API 5L Line Pipe Test Methods

Hydrostatic Test

a. Jointers need not be hydrostatically level, provided that the portions of pipe used in making the jointers were successfully hydrostatically tested prior to the joining operation.

b. Except in the previous situation, the pipe shall withstand the hydrostatic test without leakage through the weld seam or the pipe body.

Bend test

Cracks should not occur in any part of the sample and opening of weld shall not occur as well.

Please Note: For all bend tests, the weld extends to 6.4 mm (0.25 in) on each side of fusion line.

Flattening Test

The flattening test method is used to verify the deformation performance of line pipe to the specified size and display its defects. According to the stress and deformation characteristics of the specimen during the flattening process, the flattening test shall show the resistance to longitudinal cracking and circumferential cracking of the pipe and display its internal defects and surface defects.

Other than the above three common tests, there are other tests that are required in each circumstance.
Guided-bend test
CVN impact test for PSL2 pipe (including pipe body tests, pipe weld and HAZ tests)
DWT test for PSL2 welded pipe

Surface Conditions, Imperfections and Defects Appearances

All API 5L pipes shall be free from defects, cracks, sweats and leaks.

More defects as:

Undercuts in SAW and COW pipes.
Arc burns
Laminations
Geometric deviations
Hard spots
Other surface imperfections (Defects depth more than 0.125 thickness or ≤ 0.125 wall thickness refers to Clauses C in API 5L.)

API 5L Pipe Sizes and Tolerances

Tolerances for diameter and out of roundness

Tolerances for wall thickness

Tolerances for pipe lengths

API 5L pipe length tolerances shall be complied as following conditions:
a. Random length shall be delivered as below table 12.
b. Approximate lengths shall be delivered as tolerances of +/- 500 mm.

Order Information for API 5L pipe

a. Quantity in meters or in tons. Total meters or total pieces.
b. PSL1 or PSL2 (N/M/Q/NS/MS/QS), Sour Services, Onshore/Offshore
c. Pipe Types (Seamless or welded, EW, ERW, HFW, SAW, LSAW, HSAW, SSAW)
d. Reference documents to API 5L.
e. Steel Grade
f. OD (Outside diameter) and WT (pipe wall thickness)
g: Length and length type (Double random length / Single random length / Fixed length / Approximate length)
h. Individual annexes applicability of confirmation

Additional Information

The following additional information could also be included in the PO in different situations.
• Pipe designation
• Chemical composition for intermediate grades
• Carbon equivalent limits
• Diameter or round tolerances for special size pipe
• Jointer welds
• Ends type
• Repairs requirements
• CVN impact test
• DWT test
• Hardness test
• Pipe markings and end colors
Etc.

Traceability

For PSL1 pipe, manufacturer shall establish and follow documented procedures to maintain
a. The heat identity until all related chemical tests are performed and complied with the required specifications.
b. Test unit identity until all related mechanical tests are performed and complied with the related specifications.

For PSL2 pipe, besides the above terms, such documents shall provide means for tracing any length of the pipe to the proper test unit, including the related chemical and mechanical test results.

API 5L Line Pipe History and Milestones

Before API 5L pipe standard generated

1834 First cast iron pipe made at US (Millville, NJ)
1856 Converter steel making technology developed
1858 First successful oil well established in Titusville, PA
1863 Screwed couplings used in pipeline connections
1863 Pipe is made in wrought iron with furnace lap-welded seams
1893 First 30-inch diameter pipe made in lap-welded
1899 First large diameter seamless steel pipe in 20 inch is made, thickness at 5/8 inch
1917 11-mile pipeline is using electric metal arc welding
1919 API (American Petroleum Institute) is charted.
1924 Electric resistance welding with direct or low frequency current is invented
1925 Large diameter seamless pipe in 24” diameter is available
1927 Electric flash welded pipe is developed

After API 5L released

1928 First API 5L standard for manufacturing line pipe appears, covers furnace butt-welded pipe, furnace lap-welded pipe, seamless pipe. Minimum YS 172 Mpa 25000 psi, maximum 310 Mpa 45000 psi. Including material for three Grade A25, A, B, minimum yield strength was 172 Mpa, 207 Mpa, and 241 Mpa.
1931 API 5L pipe specification included ERW pipe (electric resistance welded pipe)
1933 Large diameter steel pipe mostly adopted electric arc girth welding
1944 Electric flash-welded pipe added in API 5L
1946 30-inch large diameter single submerged-arc-welding pipe begins
1948 Double submerged-arc-welded pipe (DSAW pipe) appears
1948 Release API 5LX standard, covers minimum yield strength material in 289 Mpa (42000 psi).
1953 API 5L Grade X46 and X52 pipe added
1962 Furnace lap-welded pipe removed from API 5L pipe, basic oxygen steel making processes accepted.
1963 Nondestructive inspection methods start to use in API 5L pipe specification
1966 API 5L Grade X60 pipe appears
1969 Supplemental requirements for toughness test added in API 5L
1973 API 5L Grade X70 steel pipe appears
1983 API 5L and API 5LX combined in API 5L.
1985 Grade X80 pipe appears
2000 Minimum level fracture toughness made mandatory in API 5L

Before 2000, Grade X70 pipe used in pipelines total quantity at 40%, Grade X65 and X60 was at about 30% each, small diameter pipelines also choose to Grade X52 pipe, which mostly at ERW type.

API SPEC 5L and ISO 3183

About API SPEC 5L 2018 – 46th Edition of API Pipe Standard

This version was initiated in April 2018 and effective on 1st, May 2019.

ISO 3183 standard specification for line pipe

In 2007, ISO and API did a joint release for ISO 3183:2007/API SPEC 5L 44th, to complete an international standard worldwide. Until 2012, United States claimed about the intellectual property right, so API terminated the cooperation with ISO, and no longer making standards for ISO. But the latest version of ISO 3183:2012 or API 5L 2012 still a union achievement, except API LOGO and onshore line pipe specification for European, the other content was all the same.

Differences between API 5L 45th edition and previously edition

The main difference between 45th Edition with previously is to add two additional appendixes: European onshore pipeline for PSL2 pipe order specification, (Annex M). And Equations for threaded and coupled pipe and background equations for guided bend and CVN test specimens (Annex P). As for the other content, they only have a slight difference in related standards, manufacturing technology, performances norm, inspection methods, besides adjustment of text expression. The latest version of API 5L 2012 is completer and more scientific.

API 5L Pipe Application

Modern API 5l steel line pipe belongs to low carbon or ultra-low carbon micro alloy steel. It is a high technology and high value-added product.

The steel line pipe production has applied to almost all modern technology achievements in the metallurgy field for nearly 20 years.

At present, the development trend of line pipe engineering is large diameter, high pressure gas transportation, high cold and corrosion service environment, thick wall of submarine pipeline etc.

Therefore, API 5L steel pipe should have high strength, high toughness, and brittle fracture, as well as good welding ability, and suitable for sour services and in H2S environment with anti-corrosion performances.

ASTM A270 sanitary (hygienic) stainless steel tubing is the standard specification for the welded seamless, and heavily cold worked welded austenitic and ferritic stainless steel sanitary tubing. It includes the stainless steel tube types in seamless and welded ERW, EFW. ASTM A270 sanitary tubing intended applied in the diary and food industry, bio processing equipment, and having special surface finish.

View here for about information about ASTM A270 Standard Specification.

ASTM A270 stainless steel tube size range

ASTM A270 sanitary stainless pipe usually refers to the small pipe diameters, normally from 1/2” to 2 1/2”, thickness from 0.049 in (1.24mm) to 0.15 in (3.81mm).
The maximum outer diameter of ASTM A270 tubing is 12 inches (304.8 mm).
ASTM A270 tubing using inch-pound as the standard unit of measure.
Wall thickness tolerance shall not vary more than 12.5%.

Referred standard for ASTM A270 sanitary tubing

ASTM A 262: Methods of detecting intergranular corrosion for the magnetization coefficient.
ASTM A 480/A 480 M is the general specifications for flat stainless steel, heat-resistant stainless steel plate, sheet and steel bars.
ASTM A 923 Test methods for detecting detrimental intermetallic phase in duplex austenitic/ferritic stainless steels
ASTM A 967 is the specification of passivation treatment for stainless parts .
ASTM A 1016/1016 M is the general specification for ferritic alloy steel, austenitic alloy steel and stainless steel.
E 527 is the test methods for numbering metal and alloy
ASTM B 46.1 surface structure (surface roughness, waviness and layers).
ASME boiler and pressure vessel’s numbers and other standards.

Stainless tube manufacturing processes

ASTM A270 sanitary stainless steel pipe shall be noted below points during manufacturing processes:

1) Seamless steel pipe should not contains any kind of welding processing.
2) Welded steel pipe applied in automatic welding processing, but should not use metal materials as filler.
3) Heavily cold worked (HCW) tubes shall be manufactured by cold working of not less than 35% reduction of thickness of both wall and weld to a welded pipe prior to the final anneal. Filler materials shall be noted added during welding process. The weld shall be 100% radio graphically inspected in accordance with ASME boiler and pressure vessel standards specification.
4) Sanitary pipe could be furnished with hot finished or cold finished at Manufacture’s option.

Hot-treatment methods for ASTM A270 stainless tube

All materials should supply after hot-treatment. Except the for duplex stainless steel materials S31803, S32003, S320205, S32750, N08926 and N08367, in these cases it shall consist of heating the material to a minimum temperature of 1900 ℉ (1040 ℃) and quenching in water or rapid cooling by other means.

CHEMICAL COMPOSITION

A little part of flat or steel pipe shall be taken for chemical analysis. The composition should meet the ASTM A270 standard table 1.

Table 1:

MECHANICAL TESTS

Mechanical tests includes negative flattening test, hydrostatic or nondestructive electric test. Mechanical strength shall be complied with ASTM A270 standard specification table 2.

Table 2:

TOLERANCES

SURFACE REQUIREMENTS

Surface of rolled products: No need extra polishing or smooth treatment.
Mill Finish— A finish without additional polishing oroperations intended to smooth the surface.

Mechanical polished surface: Purchasers according the same numbering abrasive (grinding stuff)  to polish the products get the required products’ surface:
Finish No. 80 – A ground finish produced by polishing a tube with an abrasive media impregnated with No. 80 grit.
Finish No. 120 – No. 120 grit.
Finish No. 180 – No. 180 grit.
Finish No. 240 – No. 240 grit.
Other mechanically polished finishes may beagreed upon between the purchaser and manufacturer

Electrolytic polishing of the surface: Before this processing, manufacturer could use other ways to polish products.
The maximum average of roughness: Customers could specify the maximum roughness of internal surface, external surface and both surface.
Surface furnishment also could be decided by manufacturer or purchaser.
Normally surface treatment: Internal, External, SF4, SF3, etc.

MARKS

At last, the mark should furnished in accordance with A 1016/A1016M, and specified in the order. Includes the sanitary stainless steel pipe manufactured in Seamless (SML), Welded (WLD) or heavily cold worked (HCW).

PACKAGE

Before delivery, all steel pipes should bundled well, and covered by paper, cloths. Or packed in box by manufacturer.

ADDITIONAL REQUIREMENTS

In case specified in the order, intergranular corrosion tests shall be performed by manufacturer on specimens representative of the as-shipped condition. Sanitary stainless steel pipe and tube shall be capable of passing corrosion tests in the as-shipped condition. For austenite alloy steel should meets the Practice E of the standard A262 , and for duplex alloy steels (S31803, S32205 and A32750) should meets experiment C of Test Methods A 923.

In case the ASTM A270 stainless steel pipe for pharmaceutical quality applications, it is more strict on the chemicals, strengths and size tolerances.