Product Description

Seamless pipe is a hollow tubular steel without welding seams, which is made by perforated hot rolling, cold drawing or cold rolling process. It has the characteristics of uniform structure, high strength and good sealing. Its surface is usually the original color of metal (silver gray), and can be galvanized, painted, plated and other anti-corrosion treatments according to needs. According to the production process, it is divided into:

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Hot-rolled seamless pipe: thick wall thickness, large outer diameter range, suitable for high pressure and high strength scenes;

Cold rolled / cold drawn seamless pipe: high precision, smooth surface, uniform wall thickness, mostly used for precision machinery or fluid transportation.

According to the material, it is divided into:
Carbon steel seamless pipe (such as Q235, 20# steel): low cost and wide application;
Alloy steel seamless pipe (such as 15CrMo, 42CrMo): high temperature, high pressure and corrosion resistance;
Stainless steel seamless pipe (such as 304, 316L): excellent corrosion resistance, suitable for food, medical, chemical and other fields.

Parameter

Standard Specification for Seamless Carbon Steel Pipe
Seamless Pipe, Mild Steel, Black Varnished and Hot-Dipped, Zinc-Coated (Galvanised)

ASTM A53/A53M Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless
Pipe ordered under this specification is intended for mechanical and pressure applications and is also acceptable for ordinary
uses in steam, water, gas, and air lines.

ASTM A106/A106M Standard Specification for Seamless Carbon Steel Pipe for High-Temperature Service
This specification 2 covers seamless carbon steel pipe for high-temperature service in NPS 1 ⁄ 8 to NPS 48 [DN 6 to DN ] inclusive, with nominal (average) wall thickness as given in ASME B 36.10M.

If you want to learn more, please visit our website Zongrun.

API SPECIFICATION 5L Specification for Line Pipe
This Standard specifies requirements for the manufacture of two product specification levels of seamless and welded steel pipes for use in pipeline transportation systems in the petroleum and 

natural gas industries

Product Item ASTM A106 GR.B Black painted & marking seamless steel pipe Size OD 1/8” -24” (5.0mm-716mm) Wall Thickness 0.3mm-26mm SCH20,SCH40,STD,XS,SCH80,SCH160,XXS Length Less than 12m Steel material ASTM 106 Gr.B API 5L Gr.B ASTM A 53 Gr.B Standard ASTM A53, BS- Zinc Weight 120g,270g,400g,500g,550g 20μm ,40μm ,60μm,70μm,80μm Usage 1)low pressure liquid, water, gas, oil, line pipe 2)construction 3)fence, door pipe Ends 1) Plain 2) Beveled 3) Thread with Coupling or cap 4) Chamfer 5) Groove 6) Screw End protector 1) Plastic pipe cap 2) Iron protector Surface Treatment 1) Bared 2) Black Painted (varnish coating) 3) Galvanized 4) Oiled 5) PE,3PE, FBE, corrosion resistant coating, Anti corrosion coating. Technique Electronic Resistance Welded (ERW ) Electronic Fusion Welded (EFW) Double Submerged Arc Welded (DSAW) Welded Line Type Longitudinal Section Shape Round Inspection With Hydraulic Testing, Eddy Current , Infrared Test Package 1) Bundle, 2) Bags Delivery 1) Container 2) Bulk carrier Port of Shipment Xingang Port, Tianjin, China Date of Delivery According To The Quantity And Specification Of Each Order Payment L/C T/T Others Fitting as screws and flange also can be supplied.

Our Hot Selling Sizes

Nominal Size (Inch) Outer Diameter (mm) SCH40 Thickness (mm) SCH80 Thickness (mm) SCH160 Thickness (mm) 1/4" 13.7 2.24 3.02 3/8" 17.1 2.31 3.2 1/2" 21.3 2.77 3.73 4.78 3/4" 26.7 2.87 3.91 5.56 1" 33.4 3.38 4.55 6.35 1-1/4" 42.2 3.56 4.85 6.35 1-1/2" 48.3 3.68 5.08 7.14 2" 60.3 3.91 5.54 8.74 2-1/2" 73 5.16 7.01 9.53 3" 88.9 5.49 7.62 11.13 3-1/2" 101.6 5.74 8.08 4" 114.3 6.02 8.56 13.49 5" 141.3 6.55 9.53 15.88 6" 168.3 7.11 10.97 18.26 8" 219.1 8.18 12.7 23.01 10" 273 9.27 15.09 28.58 12" 323.8 10.31 17.48 33.32 Nominal Size (Inch) Outer Diameter (mm) STD Thickness (mm) SCH40  Thickness (mm) SCH80  Thickness (mm) 14〞 355.6 9.53 11.13 19.05 16〞 406.4 9.53 12.7 21.44 18〞 457 9.53 14.27 23.83 20〞 508 9.53 15.09 26.19 24〞 610 9.53 17.48 30.96

Implementation standards

National standard: GB/T (for structure), GB/T (for fluid transportation), GB/T (for low and medium pressure boilers), GB/T (for high pressure boilers);
American standard: ASTM A106 (seamless steel pipe for high temperature), ASTM A312 (stainless steel seamless pipe);
European standard: EN (seamless steel pipe for pressure).

Applications

1. Industrial pipeline system
Fluid transportation: water, oil, gas (natural gas, steam) pipelines, such as municipal water supply, chemical raw material pipelines, thermal pipelines;
High-pressure scenarios: boiler pipelines (power station boilers, industrial boilers), hydraulic system pipelines (construction machinery, injection molding machines).
2. Machinery manufacturing
Structural support: automobile drive shafts, bicycle frames, oil drill pipes;
Precision parts: cylinder tubes, hydraulic cylinder barrels (high-precision cold-rolled seamless pipes are required).
3. Construction and Engineering
Steel structures: supporting columns of bridges and high-rise buildings (such as large-diameter hot-rolled seamless pipes);
Pile foundation engineering: steel pipes for piling, underground continuous wall pipes.
4. Chemical and Petroleum
Corrosive medium transportation: stainless steel seamless pipes are used to transport acid, alkali, and salt solutions;
Oil extraction: oil well pipes, casing (anti-sulfur and anti-corrosion alloy pipes are required).
5. Other fields
Shipbuilding: marine boiler pipes, seawater desalination pipes;
Medical equipment: stainless steel sterile pipes (pharmaceuticals, food processing);
Aerospace: aircraft engine oil pipes, hydraulic pipes (ultra-high strength alloy pipes are required).

Performance

1. Mechanical properties
High strength: seamless pipes have no welds, and the overall strength is higher than that of welded pipes, suitable for high pressure and impact loads;
Fatigue resistance: not easy to crack under cyclic loads, suitable for vibration environments (such as mechanical transmission pipes).
2. Corrosion resistance
Stainless steel material: 304/316L seamless pipes are resistant to acid, alkali and salt corrosion and are widely used in chemical and marine engineering;
Surface treatment: galvanizing (Zn), epoxy resin coating (EP), and polyethylene lining (PE) can further enhance the corrosion resistance.
3. Process performance
Weldability: Carbon steel and low alloy steel seamless pipes can be connected by welding, and stainless steel pipes require special welding materials;
Processability: Can be bent, expanded, reduced in diameter and other processing (cold-rolled pipes are easier to form).
4. Sealing
The weld-free design is suitable for scenarios with high sealing requirements (such as gas pipelines and hydraulic systems).

V. Packaging description
1. Conventional packaging
Small diameter pipes (outer diameter ≤108mm):
Bundled (50-200 pieces per bundle), fixed with steel or plastic belts;
Plastic protective caps are placed on the ends to prevent damage from bumps.
Large diameter pipe (outer diameter > 108mm):
Single or multiple pipes are packed in containers and wrapped with straw ropes or bubble film to prevent scratches;
Put them in wooden boxes or iron frames during long-distance transportation to prevent rolling.
2. Special protective packaging
Anti-corrosion requirements: The surface of stainless steel pipes is coated with anti-rust oil and wrapped with waterproof paper;
Precision pipes: Cold-rolled precision pipes are sealed with nylon bags to avoid dust pollution.
3. Labels
Each bundle/each pipe body is printed with: material, specification (outer diameter × wall thickness), implementation standard, production batch number, factory logo;
Outer packaging indicates: net weight, gross weight, destination, moisture-proof/anti-fall logo.

Customer Questions and Answers

1. Q: What is the difference between seamless pipes and welded pipes?
A:Structure: Seamless pipes have no welds, and welded pipes have longitudinal or spiral welds;
Strength: Seamless pipes have higher overall strength and are suitable for high-pressure scenarios (such as boilers and hydraulic systems);
Cost: The production process of seamless pipes is complex, and the price is 10%-30% higher than that of welded pipes.
2. Q: How to choose the material of seamless pipe?
A:General environment: choose Q235 or 20# carbon steel (low cost, easy to process);
Corrosive environment: choose 304/316L stainless steel or galvanized seamless pipe;
High temperature and high pressure: choose 15CrMo, 12Cr1MoV and other alloy pipes (specific temperature and pressure parameters must be provided).
3. Q: Can the size of seamless pipe be customized?
A:Regular specifications (outer diameter 6-630mm, wall thickness 0.5-50mm) can be customized in length (such as fixed length 6m, 9m);
Special caliber or wall thickness requires mold production, the minimum order quantity is higher (usually ≥5 tons), and the delivery time is extended by 2-4 weeks.
4. Q: How to detect the quality of seamless pipes?
Answer:Appearance: no cracks, folds, or scars on the surface, and uniform wall thickness;
Non-destructive testing: ultrasonic (UT) and eddy current (ET) detection of internal defects;
Pressure test: water pressure test (such as water pressure 10MPa, pressure maintenance for 5 minutes without leakage).
5. Q: How to prevent rust during transportation of seamless pipes?
Answer:Short-term transportation: can be naked in dry environment, and covered with waterproof cloth in humid environment;
Long-term storage: stored in a dry warehouse, ≥20cm from the ground, regularly check the surface rust, and re-oil if necessary.

If you need to purchase seamless pipes, it is recommended to clarify the following information in advance:

Can anyone help me I am in the following situation.

I am now considering the piping material as ASTM A53 gr.B and STAINLESS STEEL 304L.
It can be made both seamless and welded type.
I prefer welded type because it costs less money and some of them are as large as 32 inches.
But I am not sure whether it can be applied in a hydro power plant cooling water supply pipes.
If it can be applied, tell me about their durability or difference between seamless and welded.

Cooling water condition are as follows.
- sort : river water
- fluid temperature : 20 ~ max.40 centigrade.
- water supply velocity : 1 ~ 2.5 m/sec.
- pipe diameter : 1 ~ 32 in.
- pressure of water in the water supply circuit : max. 16bar

please feel free to contat with me if you need more data.

Koh. In order to know whether seamless or welded pipe can be used in your application you should consult the governing code for the construction. The difference between welded and seamless pipe as far as performance is basically none from a practical standpoint. There are two primary means of manufacturing welded pipe there is Electric Resistance Welding (ERW)small and large diameter and Double Submerged Arc Welded(DSAW)mostly large diameter. There are some issues involved with the quality of welding that can come into play with both welding processes and should be considered when making the purchase. Theses issues can be addressed with the mill if you are purchasing a large order. (Mechanical testing and NDT, third party monitoring of manf.) There are also quality issues with seamless pipe that can be addressed the same way. The key to knowing if the pipe you are purchasing is of good quality is to test it. There are third parties that can perform testing of welded and seamless pipe that you may purchase from a supplier's "on the ground" stock. Let me know if I can give more info. I agree with ElderX in that you need to check the governing code and then also what the client is expecting. They may have had experience with welded pipe that failed and may only accept seamless.

In the design of the piping, seamless is considered stronger. A way to look at it is while they both may be welded pipe; seamless pipe has gone thruough a 100% x-ray and no impurities have been found, or those found fall within the aceptable limits. In the design of the pipe, the joint efficiency factor for seamless pipe is 1.0, while for welded pipe it is 0.70, and in some case you may be able to use 0.85.

I would also request MTR's (material test reports) on the pipe you buy to ensure it falls within the parameters set forth for each type, whether you are using SA53-B, SA106-B or SA312-304L. While the "seamless" is more expensive, on critical lines and lines exposed to the human factor, we would use "seamless".

Hope this helps


I just happened to come across this post and have similiar questions about ERW vs. seamless SST piping that you might be able to help me with. We currently use seamless piping for duct burners and would like to switch to ERW due to cost savings. There is some question to ERW piping having problems due to the heat from the welding reducing the ability of the chrome in the steel to resist going into the carbide phase when heated. Basically they are saying that welded pipe does not perform as well as seamless at very high temperatures. I can seem to get a definate temp. limit or what "performance" means. Any help is appreciated jellyko,

Is your question about selection of materials or cost or what ? If you have a raw water system, without chlorides, either the carbon steel (A53 gr.B) or stainless would be acceptable. The cost for the stainless would be about double (or more) of that for the carbon steel.

If sufficient chlorides are present,the stainless may pitt and eventually fail...

At 16 bar (~240 psig) a schedule 10 pipe should be OK up to 32 inch diameter for either material.

I may be wrong, but with these modest design conditions for a raw water system, your real question should be about materials, possible coatings and installed cost?

Good Luck !!!..................................MJC Thanks for your all reply.

Above matters we will use welded pipes(ERW) on you guys help.
Because governing code is ANSI B31.1 POWER PIPING and there are no rules confining seamless or welded as I know.
There joint efficiency factor is 0.85 for (ERW).

But I can't handle the corrosion factor.
Therefore if I consider 20 years of warrenty, how much do I consider for their additional thickness?
See my first question for application details.
PH of river water is 7.5 average.
Should I contact corrosion engineer for this matter?
Let me know the related document or specification if any.
Painting protection may not be allowed in this application(inner part).

Our application are both stainless and carbon steel depends on their function(separated lines).
I am doing this job to minimize the installed cost for sure.

Regards, jellyko Gthomas, unfortunately it's not quite that simple. The welding process does change crystal structure, the composition of the metal and hence the mechanical and physical properties of the metal. These changes mean that at various locations across the weld and heat effected zone, you are dealing with effectively different alloys and different grain sizes etc.

Your specific application also needs to be investigated, as a result, as temperature is not the only restraint, you also need to know which gasses are involved, etc. Possibly the best idea, is to start seeing how the welded tube performs for situation, by replacing a section of the existing tube.

I hope this helps. I'd like to add two brief cautions to the excellent information you have already received:

1. Corrosion testing versus open natural source water can't be done out of textbooks. As a couple of colleagues have already stated, "suck it and see" testing (ie actual trials) is necessary.

2. The corrosion resistance of some stainless steels depends on the ability of their chromium content to form a self-healing skin on the surface of the alloy. When the steel is heated, the chromium reacts with carbon to form a carbide, thereby depleting the amount of chromium that is available to resist corrosion. That reaction is one of the reasons why certain stainless alloys lose much of their corrosion resistance when they are improperly heat treated or welded. This is a rough explanation. A more accurate one would be available in a textbook on stainless teels. When considering weather to use seamless or rolled and welded plate, you should check the tolerances in the material specification. I think the material specs you referenced have a plus or minus 12 1/2% tolerance for seamless pipe whereas the rolled and welded plate will have a much lower fabrication tolerance. These tolerances must be considered in your design calculations. Welded stainless pipe can be restored to full passivity by proper heat treating. This usually involves heating austenitic SS to about F and water quenching. Ferritic stainless is heated to about F and quenched. HOWEVER, if the SS is an "L" grade (low carbon, ie, under about .04%) there is usually no need to heat treat the pipe since there is very little carbon available to form chromium carbides. Carbon steel will corrode internally and externally and will require internal coating and external corrosion protection. The latter may be cathodic protection (CP) or wrapping (with or without CP.

Common, austentic stainless steels at the conditions you mention - especially if the lines run full and are not left to "stew" for many weeks at a time - will not require internal or external corrosion protection under most circumstances. This is especially true if the welds - circ and long. - get proper post weld cleaning to prevent localized corrosion (and reduce chances of MIC). At todays prices for 304L or 316L stainless steel welded pipe I'd be surprised if this option is not the winner. ElderX gave you some good info and I hope I can add a little to it. One other thing to consider is that welded pipe whether EFW (Electric Fusion Welded) or ERW (Electric Resistance Welded) will have specific joint factors (again considering applicable codes.) When considering allowable working pressures pipe that has the welded joint 100% x-rayed and approved will have a joint factor of 1.0 making it equivilant to seamless pipe. If the x-ray tests are not performed it will have a joint factor of .85 so allowable pressures would have to be reduced by that factor. The quality of both welding and non-desrtuctive testing has advanced so much that any consideration of welded pipe being inferior to seamless is quite obsolete. Besides, making seamless stainless steel pipe is an onerous, defect-plagued process while producing welded pipe is a very robust process. There are numerous quality producers.
Just be sure that you specify very low sulfur content, i.e.less than 0.003%. In the past many welded pipe producers used high sulfur ( >0.008% )to facilitate welding, but this results in greatly diminished pitting corrosion resistance.
Welded pipe is made from flat-rolled steel which gives it much better wall uniformity than seamless.
Laser-welded pipe is best, but erw is also fine.
Welding does not diminish corrosion resistance. In heavier sections, low carbon stainless is used to ensure that carbides do not precipitate during cooling from welding temperature. I am assuming you do not have a preferred site practice; in that case if you decide to go for welded pipe, be extra vigilant in verifying manufacturing quality. This can be done by 1) placing stringent conditions on the PO to avoid liability issues later and, 2) inspection and tests (hardness, x-ray, MPI, UT, MPI). This may seem over the top, but can save embarrassment later.

This thread gets a prize for going on forever, but the
messages are certainly useful and interesting.

Japanese engineers have many years of experience with
stainless pipe in water supply service, including high-
pressure and superheated service.

You might find references in their literature (much of
which is in English) about differences in performance
between welded and seamless pipe.

Neverthelesss, you would want to test actual supplier
samples before committing to specifications or bulk purchase. I would like to make the following recommendation:
- For sizes larger than 14", go for welded pipes anyway. You may choose A672 (for CS)and A358(for SS)which are fusion welded pipe specifications. These can be used in all applications where seamless pipes are used for lower sizes.
-For sizes <14", consider both seamless and ERW. For conditions stated, welded pipe would do just fine.At times, seamless pipes can be procured with very little cost differential which must also be considered. LOL @ Tedg. The initial post was in ! This is an aged thread/

For what it's worth, our process chemical plant would not use ERW for hazardous pressure services regardless of codes.

ERW CS pipe in a water service is used though, knowing that preferential corrosion at the weld seam will probably see the ERW requiring replacement well before the seamless equivalent.

We've only ever used ERW SS pipe in air-conveyor services.

5 year thread... and going strong!