When selecting the ideal pipe for your requirements, there are a number of elements to take into account. One crucial decision you must make is whether to opt for ERW or seamless steel pipe.
Erw pipes are constructed by welding pieces of metal together longitudinally along their length. Seamless pipes, on the other hand, are created by extruding metal into desired lengths without any welds or seams along the way.
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Cost
Both ERW and seamless pipe are made from steel, but their production processes differ. The most notable distinction is that ERW pipe is created through electrical resistance welding.
This process begins by heating a solid steel billet and casting over a piercing rod to form a hollow tube. Once the rod has been ground off, leaving behind only an even seam running along its entire length.
Erw pipes tend to be cheaper than seamless ones due to their simpler manufacturing process that makes them cheaper. Unfortunately, erw pipes tend to corrode more easily, making them unsuitable for high-pressure jobs.
Seamless steel pipe is another type of welded pipe, but its production process is more intensive and costly. In many instances, it’s even pricier than ERW pipe in some cases.
Erw pipes are commonly used for low-pressure applications that don’t need corrosion resistance. While they have less of a tendency to burst or break under pressure than seamless pipes, they cannot handle major tasks like oil and gas piping.
ERW pipes are a popular choice for residential applications due to their affordability and variety of sizes. Not only that, but they’re also great at protecting walls against water damage if left uncovered.
Another advantage of erw pipes is their ease of handling. They can easily be transported in trucks, trains and other vehicles without causing any issues. Furthermore, you don’t have to worry about damage when installing them in tight spaces either.
Erw pipes are not only affordable, but they come in an array of colors and styles as well. Usually black, they can also be painted to match other color schemes for interior or exterior installations.
To determine whether a pipe is erw or seamless, look for a stencil on the side with specifications and standards. For instance, if it reads ASTM A53, then you know it’s an erw pipe.
ERW and seamless pipes are both excellent choices for residential projects, but they may not be the most suitable options when it comes to commercial uses. Unless you plan on using them in an extremely corrosive environment, the extra expense just isn’t worth it.
Corrosion
When selecting steel pipes for various applications, the type of welding used can make a big difference. Make sure to get the right product for your job when considering which type of pipe best meets your needs.
The most widely-used type of pipe is ERW (electric resistance welded), which features a welded seam. This type of material has many applications and is frequently found in the oil and gas industry and other industries that need high-pressured pipes.
ERW piping is usually more cost-effective than seamless pipes and comes in various sizes and lengths due to its simpler manufacturing process compared to that of seamless pipes.
However, there are some disadvantages to ERW piping that you should be aware of. Firstly, it isn’t as durable as seamless pipe and this could prove a major issue if working under high pressures is your goal.
Another major concern is corrosion. Both ERW and seamless pipes can be vulnerable to this issue due to their welded seam, but ERW in particular has an increased chance of developing this issue due to its more exposed structure.
Senitization can weaken a seam line, encouraging intergranular corrosion that can harm both the steel itself and its pipe counterparts.
Furthermore, ERW pipe may not be as straightforward to install as seamless pipes due to its weld seam that may be difficult to access and even harder to tack down, making installation both time-consuming and costly.
Thankfully, there are ways to mitigate these issues. One option is heat-affected zone welding – an innovative welding technique that uses an arc to form a weld on the exterior of steel pipes.
Another method is high-frequency welding (HFW). This relatively new welding technique has the potential to be more efficient and cost effective than other techniques of joining metals.
Strength
ERW pipes boast greater mechanical strength than seamless pipes, making them the ideal choice for industrial applications where pressure and temperature will be higher. This includes oil & gas, power generation, pharmaceutical industries and other sectors requiring durable pipelines that are reliable and safe.
ERW steel pipes are distinguished by their high wall thickness uniformity and ellipticity, which contribute to their higher crush resistance than seamless tubes. Furthermore, impact toughness of ERW pipe is several times higher than that of seamless steel tube due to control over impurity content, slitting height/direction, shape of the forming edge, welding angle/speed/heating power/frequency etc.,
In addition to their superior strength, ERW pipes are easier to fabricate than seamless ones. Forming seamless pipes requires multiple steps that may prove challenging when producing large amounts of them.
Another advantage of ERW pipe is its versatility; it can be formed into various shapes. This makes it perfect for crafting specialized pipe products like fittings and valves that need precise connections and fit together securely.
However, ERW pipe can be vulnerable to intergranular corrosion, which weakens the steel and causes it to break down. This is especially true in the oil and gas industry where pipe integrity and fittings are vital for maintaining pipeline function at all times.
Welded pipe can also be susceptible to stress cracks, which are caused by the heat and pressure involved in welding. This could cause the edges to deform and reduce the quality of welded products.
Seamless pipe, unlike ERW, is manufactured using an entirely different technology and avoids the same problems. This is because the manufacturing process involves cold drawing instead of hot rolling, meaning the edges of the metal don’t deform during processing.
Appearance
When selecting steel pipes for your project, there are numerous factors to take into account. You must determine what applications require them and what pressure levels will apply, among other things.
Generally, welded pipes are stronger and better equipped to withstand higher pressures. However, this doesn’t guarantee they’ll fit every application perfectly.
When working with a company offering both types of pipe, you can always request samples to decide which is most suitable. Doing this helps you avoid making an expensive mistake that could affect the final quality of your project.
Another way to determine whether a tube is seamless or ERW is by inspecting its stencil on the tube. If you don’t have access to a sample, you can also examine the grain structure of the pipe to identify its type.
The ERW process involves welding two uncoiled rolls of steel sheets together using high-frequency current, eliminating the need for welding filler wire or metal. This method has the advantage of being cost-effective, as no welding filler wire or metal is used – making it a cost-effective manufacturing option for welded pipe.
Furthermore, ERW pipes are more durable than seamed ones due to their consistent wall thickness and corrosion resistance. They can withstand significantly greater levels of pressure and temperature than their counterparts, making them suitable for a range of industrial uses.
ERW steel pipes offer greater flexibility and versatility when it comes to internal dimensions when compared to SMLS steel tubes. Furthermore, they exhibit greater resistance to cracking and bending during manufacturing, making them suitable for a range of applications.
Aside from these advantages, ERW steel pipes are more cost-effective than SMLS steel tubes due to their lower production costs. This is due to the fact that ERW pipes are formed from a sheet of steel during cold rolling while SMLS tubes require piercing round steel during hot rolling.