ERW Pipe vs Seamless Cost

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Seamless steel pipes have a hollow section and are used in large quantities as pipelines for conveying fluids, such as pipelines for conveying oil, natural gas, gas, water and certain solid materials. Compared with solid steel such as round steel, steel pipe has lighter weight when the bending and torsion strength is the same, and it is an economical section steel. ERW steel pipe " is Electric Resistance Welding, abbreviated as ERW. It is used to transport oil, natural gas and other vapor and liquid objects. It can meet various requirements of high and low pressure. It currently plays a pivotal role in the field of transportation pipes in the world.

1. Different molding methods

The seamless steel pipe is a steel pipe perforated from a whole round steel without welds on the surface.

ERW steel pipe refers to a steel pipe that is bent and deformed into a round shape by a steel strip or a steel plate, and then welded to a steel pipe with seams on the surface. The welding method of ERW steel pipe is high-frequency induction heating, which uses high-frequency induction current to heat the edge of the formed coil, and uses squeeze rollers for extrusion welding. 

Different production processes have different impacts on costs. The production process of seamless steel pipes is precise and the cost is high, so the price is relatively expensive; while the production process of welded steel pipes is relatively simple and the price is more affordable.

2. Different quality requirements

The quality requirements of seamless steel pipes are relatively high, and it is necessary to ensure that there are no internal defects, a smooth appearance, and no burrs. However, due to the limitations of the production method, it is difficult to avoid defects such as cracks and pores in the welded parts of ERW welded steel pipes. High-quality seamless steel pipes require higher raw material and precision processing costs, and the price is correspondingly higher.

3. Different price

The price of seamless steel pipe is more expensive than ERW steel pipe and the quality is better. The price of seamless steel pipes of the same specification is generally about 30% higher than that of welded pipes, and the price difference for large diameters is even greater. The required stress of seamless steel pipes can be much higher, and welded steel pipes are generally about 10Mpa, so seamless steel pipes are more expensive.

4. Different service life

Seamless steel pipes have higher strength indicators such as compression resistance and tensile strength than ERW welded steel pipes, and have a longer service life.

5. Different application scope
Seamless steel pipes: general-purpose seamless steel pipes are rolled from ordinary carbon structural steel, low-alloy structural steel or alloy structural steel, and have the largest output. They are mainly used as pipelines for conveying fluids or manufacturing structural parts and mechanical parts, such as oil drills. Rods, automobile drive shafts, bicycle frames, and steel scaffolds used in building construction are made of steel pipes to make ring parts, which can improve material utilization, simplify manufacturing procedures, and save materials and processing man-hours.

Seamless steel pipes: general-purpose seamless steel pipes are rolled from ordinary carbon structural steel, low-alloy structural steel or alloy structural steel, and have the largest output. They are mainly used as pipelines for conveying fluids or manufacturing structural parts and mechanical parts, such as oil drills. Rods, automobile drive shafts, bicycle frames, and steel scaffolds used in building construction are made of steel pipes to make ring parts, which can improve material utilization, simplify manufacturing procedures, and save materials and processing man-hours.

ERW steel pipe: ERW longitudinally welded pipe is mainly used in water supply engineering, petrochemical industry, chemical industry, power industry, agricultural irrigation, and urban construction. For liquid transportation: water supply and drainage. For gas transportation: coal gas, steam, liquefied petroleum gas. For structural purposes: as piling pipes and bridges; pipes for docks, roads, and building structures.

ERW straight seam welded pipes are generally used as wire casings in the power industry. Performance characteristics: 100% ultrasonic testing of the base material to ensure the internal quality of the pipe body; no uncoiling-disc shearing process, base material pressure pit , Less scratches; After the stress is eliminated, the finished pipe basically has no residual stress; the weld seam is short, and the probability of defects is small; it can conditionally transport the moist sour natural gas; After the diameter is expanded, the geometrical size of the steel pipe is high; welding It is carried out in a straight line in the horizontal position after the forming is completed. Therefore, the control of staggered edges, slits, pipe diameter and circumference is better, and the welding quality is excellent.

6. Market demand

Seamless steel pipes are widely used in petroleum, chemical industry, machinery, rail transit and other fields. Due to the particularity of applications and quantity requirements, the price of seamless steel pipes is relatively high. Affected by market competition and market demand, the price of ERW steel pipes is relatively low.

Overall, seamless steel pipes are more expensive than ERW welded steel pipes. Because the production process and quality requirements of seamless steel pipes are higher, and the market demand is also more specialized. But this does not mean that ERW steel pipes are cheaper in all cases, and they need to be considered comprehensively based on specific circumstances.

Tips: ASTM A53 covers seamless and welded steel pipe with nominal wall thickness. The surface condition is usually black and hot-dipped galvanized. ASTM A53 is produced mainly for pressure and mechanical applications, and is also used for transport of steam, water, gas line pipes.
A53 Grade B Seamless is our most polar product under this specification and A53 pipe is commonly dual certified to A106 B Seamless pipe.

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When to Use Seamless and Welded Pipe

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When to Use Seamless and Welded Pipe

When to Use Seamless and Welded Pipe

SmallInfo

(Petroleum)

(OP)

24 May 23 06:59
I have to choose pipe welded or seamless for raw gas but it's for 10 to 15 years not more than that, its API 5L X42 fluid is corrosive, no high temperature and pressure. I am looking for any reference from any standard which tells when to use welded and seamless or at least some valid technical points to defend my selection.
Thanks in advance.

Hi Experts,I have to choose pipe welded or seamless for raw gas but it's for 10 to 15 years not more than that, its API 5L X42 fluid is corrosive, no high temperature and pressure. I am looking for any reference from any standard which tells when to use welded and seamless or at least some valid technical points to defend my selection.Thanks in advance.

Replies continue below

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RE: When to Use Seamless and Welded Pipe

LittleInch

(Petroleum)

24 May 23 07:33

What design code?

How corrosive?
With what?
Size and wt affect availability. Above about 16 to 20" seamless gets hard to find

This is more of a material selection issue and I don't know if any pipeline code which will tell you this. B31.3 doesn't like welded pipe for some reason and applies a factor on wall thickness

There is a lot of preferential engineering here and different companies have different views.

There should be little difference but you may need to look at the impact of the seam weld on corrosion issues.

If you have sour service (H2S) then seamless is definitely preferred, which is a material selection issue under the NACE standards.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: When to Use Seamless and Welded Pipe

SmallInfo

(Petroleum)

(OP)

24 May 23 12:51

LittleInch,
Its H2S rich
b31.8
8" size
Client will ask why I am selecting seamless or welded.
Thanks for reply

RE: When to Use Seamless and Welded Pipe

LittleInch

(Petroleum)

24 May 23 13:48

It's all about the hardness of the weld. Also look in your sour service specification.

Design wise in 31.8 it makes no difference and they won't guide you as it is not something B31.8 does.

You need to ask a materials engineer, but I'm pretty sure for sour service you need seamless if possible and 8" the cost is about the same.It's all about the hardness of the weld. Also look in your sour service specification.Design wise in 31.8 it makes no difference and they won't guide you as it is not something B31.8 does.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: When to Use Seamless and Welded Pipe

TiCl4

(Chemical)

24 May 23 15:30

A general rule for corrosive services is that seamless piping is preferred - ERW pipe tends to be attacked along the pipe-weld bondline at a higher corrosion rate than the base material. My impression (not fact!) is that mill tolerances for wall thickness are either higher for seamless pipe over ERW pipe or that they are harder to get within tolerance (more expensive). So if you need to do branch reinforcement calculations for larger diameters or higher T&P, the mill tolerance becomes important.

Piping codes don't generally tell you what pipe to use in a given application; there are generally too many factors and special cases, so they leave the application up to the user.

RE: When to Use Seamless and Welded Pipe

EdStainless

(Materials)

24 May 23 16:10
Seamless also usually has a rougher ID surface.
In ERW steel pipe there can be selective HAZ corrosion attack because it isn't full body heat treated after welding.

Seamless will have much more variation in wall than welded.Seamless also usually has a rougher ID surface.In ERW steel pipe there can be selective HAZ corrosion attack because it isn't full body heat treated after welding.

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P.E. Metallurgy, consulting work welcomed

RE: When to Use Seamless and Welded Pipe

weldstan

(Materials)

Related links:
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24 May 23 17:32

For your application choose seamless due to answers provided above. Due to our global supply chain and the vast differences in ERW welding methods from mill to mill and quality thereof, a greater chance of failure is incurred using ERW. ERW pipe can be made with excellent properties but you really have to know the mill's capabilities.

RE: When to Use Seamless and Welded Pipe

MJCronin

(Mechanical)

24 May 23 18:13

• No piping code or standard will tell you when to use more expensive seamless piping and when not to

• Are you selecting schedule 80 pipe for this corrosive service ? Having a thicker wall will make the piping last longer

• Some B31 series piping codes have a higher allowable stress for seamless piping ..Seamless pipe can withstand 10-20% more working pressure than welded ones of the same material grade and size.. On what basis was your pipe wall thickness calculated ?

https://specialpipingmaterials.com/seamless-welded....

MJCronin
Sr. Process Engineer

My two cents ...MJCroninSr. Process Engineer

RE: When to Use Seamless and Welded Pipe

TiCl4

(Chemical)

24 May 23 21:28

MJCronin,

When would the MAWP of the piping become the deciding factor for a piping system's thickness at low temperature and pressure? In my mind, required thickness is often very low at low T&P, and other factors like maximum unsupported span and extra thickness for corrosion allowance tend to dominate. Typically pressure is also limited by the flanges or connectors rather than piping, is it not?

I'm not challenging you here, but rather curious as to where you've seen or heard of the extra MAWP of the seamless pipe being important in the selection of ERW vs seamless.

RE: When to Use Seamless and Welded Pipe

SmallInfo

(Petroleum)

(OP)

25 May 23 06:47

Littleinch, TiCI4, Edstainless, Weldstan, MJCronin
Thank you so much for your valuable time and information you shared, now its clear to me.
Thanks again you all

RE: When to Use Seamless and Welded Pipe

EdStainless

(Materials)

25 May 23 15:38
Many ASME codes do derate welded tube by 15% for no reason other than it was welded.
The seamless tube will always be heavier and the thinnest spot will be thinner than with welded tube.
The greater wall variation is just a fact of life.

At thicker walls the seamless premium is not very much more expensive.Many ASME codes do derate welded tube by 15% for no reason other than it was welded.The seamless tube will always be heavier and the thinnest spot will be thinner than with welded tube.The greater wall variation is just a fact of life.

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P.E. Metallurgy, consulting work welcomed

RE: When to Use Seamless and Welded Pipe

r

(Mechanical)

25 May 23 16:24

For 10-15 years choose the cheapest.

Regards

RE: When to Use Seamless and Welded Pipe

(Petroleum)

25 May 23 16:29

Each great project company in oil industry have its own basic engineering specs based on standaed codes, I am afraid you won´t recieve the wright answer here.

REGARDS

RE: When to Use Seamless and Welded Pipe

Daren Samy

(Mechanical)

2 Jun 23 01:48

Use seamless pipe. ERW pipe is not recommended in severe conditions. Welded point is weak points and it is at risk of failure

Daren!

RE: When to Use Seamless and Welded Pipe

dik

(Structural)

2 Jun 23 04:09

Quote (I am afraid you won´t recieve the wright answer here.)

... but informative, nonetheless.

... but informative, nonetheless.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: When to Use Seamless and Welded Pipe

(Petroleum)

2 Jun 23 13:33

Seamless steel pipe is better than welded pipe. Seamless steel pipe is limited in larged diameters up to 24".

RE: When to Use Seamless and Welded Pipe

r

(Mechanical)

2 Jun 23 14:37

@
You are wrong.
See SA-106
1.1 This specifcation covers seamless carbon steel pipe
for high-temperature service (Note 1) in NPS 1/8 to NPS 48
[DN 6 to DN ] (Note 2) inclusive, with nominal (aver
age) wall thickness as given in ASME B36.10M

Regards

RE: When to Use Seamless and Welded Pipe

(Petroleum)

2 Jun 23 14:50

r
you're right, I was speaking generally. But the use of welded pipe and seamless pipe depends on the intended service. If it is going to be used for a lethal dangerous, high pressure or corrosive service I would use seamless pipe, if it is going to be used in an enoquo service I would use the cheapest welded pipe.

RE: When to Use Seamless and Welded Pipe

EdStainless

(Materials)

2 Jun 23 15:33
With welded you get very uniform surface finish inside and out along with very uniform wall thickness.
The type of welding will dictate the nature of weld imperfections that you should be testing for, and the HT method (local to weld or full body) will influence the final properties of the pipe.
Seamless pipe will always have very significant wall thickness variation (commonly over +/-10% in each length) and the ID surfaces can have significant variation in surface.
Tears and cracks on the ID surface are not uncommon in seamless product.
Seamless over ~24" OD is usually forged hollows made in short lengths.

Seamless pipe isn't better than welded, it just has different types of defects in it.With welded you get very uniform surface finish inside and out along with very uniform wall thickness.The type of welding will dictate the nature of weld imperfections that you should be testing for, and the HT method (local to weld or full body) will influence the final properties of the pipe.Seamless pipe will always have very significant wall thickness variation (commonly over +/-10% in each length) and the ID surfaces can have significant variation in surface.Tears and cracks on the ID surface are not uncommon in seamless product.Seamless over ~24" OD is usually forged hollows made in short lengths.

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P.E. Metallurgy, consulting work welcomed

RE: When to Use Seamless and Welded Pipe

jmec87

(Mechanical)

2 Jun 23 16:15

Ed, thanks for that helpful explanation. I had previously assumed that seamless pipe was better than welded (in part due to the longitudinal weld joint quality factors in ASME B31.3), but your comment has helped me to better understand the differences.

RE: When to Use Seamless and Welded Pipe

dik

(Structural)

2 Jun 23 18:00

Quote (The type of welding will dictate the nature of weld imperfections that you should be testing for)

Can you elaborate on that a bit, or point me in the direction of some literature? This thread is not my type of work, but is very interesting. Thanks...

Ed...Can you elaborate on that a bit, or point me in the direction of some literature? This thread is not my type of work, but is very interesting. Thanks...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: When to Use Seamless and Welded Pipe

EdStainless

(Materials)

2 Jun 23 21:01
These are only fusions welded, no ERW and there is no filler used.
So you have TIG, Plasma, Laser, EBeam, and variations/combinations of these.
Traditionally the worry has been hot cracking of welds which tend to be transverse and this has lead to the very common use of Eddy Current testing. ECT will easily detect transverse indications with high sensitivity.
However we know that all fatigues cracks will start at longitudinal indications. The only good way to detect these is using Ultrasonic testing.
This especially applies to tubing that has been cold drawn where draw scratches and other issues will all be longitudinal.
To put some scale to this when we make aerospace hydraulic tubing (welded and as-cold-drawn 21-6-9 SS) the UT uses notches that are 0.002" deep and 0.25" long, on both the ID and OD.
All of our seamless tubing was UTed.
And for highly fatigue sensitive alloys like Ti all tubing (welded or seamless) is UTed as well.
Start with a list. what is the weld method and what are the most likely weld defects?
What NDT methods are available (listed in applicable specs)? What will they detect and with what sensitivity?
Also consider the impact of HT. In steels with weld-only HT there are a ton of local HAZ issues to consider.

Since most of my last 30 years has been in SS and Ni alloys I'll speak from there.These are only fusions welded, no ERW and there is no filler used.So you have TIG, Plasma, Laser, EBeam, and variations/combinations of these.Traditionally the worry has been hot cracking of welds which tend to be transverse and this has lead to the very common use of Eddy Current testing. ECT will easily detect transverse indications with high sensitivity.However we know that all fatigues cracks will start at longitudinal indications. The only good way to detect these is using Ultrasonic testing.This especially applies to tubing that has been cold drawn where draw scratches and other issues will all be longitudinal.To put some scale to this when we make aerospace hydraulic tubing (welded and as-cold-drawn 21-6-9 SS) the UT uses notches that are 0.002" deep and 0.25" long, on both the ID and OD.All of our seamless tubing was UTed.And for highly fatigue sensitive alloys like Ti all tubing (welded or seamless) is UTed as well.Start with a list. what is the weld method and what are the most likely weld defects?What NDT methods are available (listed in applicable specs)? What will they detect and with what sensitivity?Also consider the impact of HT. In steels with weld-only HT there are a ton of local HAZ issues to consider.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: When to Use Seamless and Welded Pipe

dik

(Structural)

2 Jun 23 22:09

Thanks, Ed... much appreciated... I owe you a beer...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: When to Use Seamless and Welded Pipe

r

(Mechanical)

3 Jun 23 02:38

Seamless pipe is the best choice for forming operations involving coiling, bending, etc.

Regards

RE: When to Use Seamless and Welded Pipe

SJones

(Petroleum)

3 Jun 23 07:58

If the party responsible for purchasing the pipe is not operating a pipe mill appraisal scheme, and will simply go with a mill that is listed on the API Composite List, then it would sway the selection towards seamless even if it is more expensive. It will also aid inspection, should purchaser inspection be deployed, since there will not be any welding, and weld NDT, activity to monitor.

Steve Jones
Corrosion Management Consultant

www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

RE: When to Use Seamless and Welded Pipe

(Petroleum)

3 Jun 23 12:35

I agree with you SJones, you merith my star!

RE: When to Use Seamless and Welded Pipe

EdStainless

(Materials)

3 Jun 23 23:49
You need align the usage and the product.
"you don't get what you expect, only what you inspect"
If you are not willing to send a specialist to the mill then you are agreeing to take the worst product that they might make.
Even with seamless there is HT, lab testing, and NDT that need to be done right.

r, not necessarily. The better diameter and wall uniformity of welded pipe often make it much easier to form.You need align the usage and the product."you don't get what you expect, only what you inspect"If you are not willing to send a specialist to the mill then you are agreeing to take the worst product that they might make.Even with seamless there is HT, lab testing, and NDT that need to be done right.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

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