Category: Stainless Steel Pipes

Difference Between Seamless & Welded Stainless Steel Pipes

One of the most versatile alloys used in manufacturing and fabrication is stainless steel. SS pipes are being used in a wide range of industries. Seamless steel pipes and welded steel pipes are the two most common types of stainless steel pipes.

Seamless pipes are made from solid steel sheets or bars that are formed into solid round shapes called “billets,” which are then heated and cast over a form like a piercing rod to form a hollow tube or shell. It’s made out of a steel cylinder. After heating the bar to a high temperature, a probe is inserted into the cylinder to make a hole. It’s a circular pipe with a hollow section and no seams. The seamless steel pipe is made from carbon steel, alloy steel, stainless steel ingots, or solid tube blanks, and then rolled. These pipes are known as superior to welded pipes as they are built using monolithic steel billets, with intrinsic mechanical strength, without seam welds.

Welded pipe is a type of pipe with a steel pipe joint on the surface that is formed by bending steel belt or steel plate material into round, square, or other shapes. After that, it’s welded into place. A roller or plate bending machine is used to cold form a flat strip, sheet, or plate into a round or circular shape. A high-energy source is then used to weld the pipe with or without filler material. Welded pipes come in a variety of sizes and can be made of length. Stainless Steel 310S Welded Pipes are typically used to transport large amounts of water, oil, or gas.


The difference between Stainless Steel Seamless Pipes & Welded Pipes is: – 


  • Appearance

Steel billet has been used as a raw material for seamless steel pipe. The hot rolling process cannot remove the outer surface defects of the billet; they must be polished after the product is finished. The defect can only be partially eliminated during the wall reduction process. In contrast, Welded steel pipe is made from a hot rolled coil as raw material, and the surface quality of the coil is identical to that of the pipe, making it simple to control. Hot-rolled coils have a high-quality surface. Welded steel pipe has a much higher surface quality than seamless steel pipe.

  • Molding Process 

In the rolling process, seamless steel pipes can be created just once. Welded steel pipe is made from steel strip or steel plate and is fabricated through bending and various welding processes.

  • Performance and usage

Seamless steel pipe has a higher strength and pressure capacity than ERW welded steel pipe. As a result, it is widely used in the high-pressure equipment and boiler industries. The welding seam of a welded steel pipe is typically the weak point, and its quality has an impact on overall performance.

Welded steel pipes can withstand 20% less working pressure than seamless steel pipes. As Stainless Steel 316 Seamless Steel Pipes are dependable is used in the high range. All industrial pipelines are made of seamless pipes because they are subjected to extreme thermal, chemical, and mechanical loads. Welded pipes are preferred in the aerospace, automobile, and electronics industries, where the budget and work pressure on the pipes are both relatively low.

  • Corrosion

Not until it is exposed to a highly corrosive environment seamless steel pipe does not show signs of corrosion, whereas the weld area in welded tubes is much more susceptible to corrosion attacks. Because a welded area is considered homogeneous, it has a different malleability, lower corrosion resistance, and more dimensional variation. Seamless steel pipes eliminate these problems and thus provide excellent corrosion resistance.

Benefits of Seamless Pipes:

  • Strength.
  • Corrosion resistance.
  • Resistance to high pressure.
  • Durability.
  • Higher Purity of material.
  • Can be used for critical applications in harsh environments.

Benefits of Welded Stainless Steel Pipes:

  • Cost-efficient
  • Faster manufacturing
  • Easily customizable
  • Consistent concentricity
  • Higher tolerance

Welded steel pipes are widely used in boilers, automobiles, shipbuilding, furniture, agricultural machinery, scaffolding, wire conduit, top shelves, containers, and other applications. Whereas Seamless pipes are used in Seawater applications, Gas and fluid transfer, Chemical lines, Oil and gas flow lines, Chemical and heat processing plants.

What Is Welded Pipe And What Are They Used For (SS 310 Welded Pipe)

The welded pipe is made by forming flat products (strip, sheet, or plate) to the desired shape, in this case normally round. Once the desired shape is achieved, a high energy source is used to melt the metal locally at the weld joint. It is squeezed together and allowed to solidify, forming a weld bead. The high energy source can be an electric arc, a plasma arc, a laser beam, or even an electron beam.  The welded weld bead is usually a bit thicker than the adjacent base metal and needs to be changed to match the base metal thickness and to correct unwanted physical, chemical, and corrosion resistance attributes of the weld.

Welded pipe manufacturing

  • At the beginning of the ASTM A312 SS TP 310 Welded Pipes manufacturing process also known as slabs or billets are cast in a steel mill. Dependent on the external dimensions and wall thickness there are different methods of producing welded pipes: Electric Resistance Welding (ERW), Fusion Welding (EFW), and Double Submerged Arc Welding (DSAW). In the ERW and EFW manufacturing process welded pipes are formed by hot or cold rolling plate and welding the seam.
  • To keep the outside (O.D.) surface of a welded pipe smooth and uniform a cutting tool called scaring blade is used to remove the weld flash. Scaring from the inside (I.D.) welded flash is also possible. With heat-treating at the end of the manufacturing process, the weld zone of the steel pipe can be made less visible.
  •  Due to the weld seam, lower operating pressures are stated by ASME compared to seamless pipes. In generally welded pipes possess tighter dimensional tolerances than seamless pipes and are less costly if produced in the same quantities.

Uses of SS 310 Welded Pipes

  • Welded steel pipes for low-pressure fluid transportation are used to transport water, gas, steam, compressed air, etc. structural welded steel pipes can be used to manufacture scaffolds, trusses, towers, playgrounds, railings, etc.
  • Steel door metal window-formed tube is used to make metal door metal window, metal to update wooden. Wire bushings are used to put a cord and cable. The car driveshaft tube is used to fabricate the car pressure shaft assembly.
  • Mechanical shape tube is used to fabricate diverse machines and accessories. It may be used as a belt conveyor roller, deep properly pump tube, sprinkler irrigation pipe, diverse pipe fittings for automobiles, diverse pipe fittings for bicycles, etc.
  • SS 310 Welded Pipes are particularly used to fabricate fixtures of diverse metal-wooden structures. Small-diameter diameter pipe may be used as radiator pipe of refrigerator-freezer, high-stress oil pipe for car, brake pipe.
  • Boiler tubes are used to fabricate steam generator tubes, superheated steam tubes, water pipes, pipes, air preheated tubes, and warmth exchanger tubes. Oil pipe is used as oil pipe, casing, and oil pipeline. Spiral welded pipe is used as conveying pipeline and big diameter directly welded pipe is likewise used as conveying pipeline. The exclusive segment tapered welded pipe is used as a lamp post. Composite pipe, the natural lined pipe may be utilized in unique programs proof against diverse corrosion. Stainless 310 welded pipes are on the whole used withinside the chemical enterprise & meals enterprise.