Difference between Seamless Stainless Steel Pipe and ERW Stainless Steel Pipe

There are some customer don’t know how to distinguish the seamless stainless steel pipe and ERW stainless steel pipe. Today, Prime Steel Pipe will discuss about differences between seamless stainless pipe and ERW stainless steel pipe.

What is the raw material required for manufacturing seamless & ERW stainless steel Pipes? Seamless Steel Pipe is made from a solid round steel ‘billet’ which is heated and pushed or pulled over a form until the steel is shaped into a hollow tube. Billets are procured both from indigenous suppliers and from abroad. HR Coils are required to manufacture ERW stainless steel pipes.

How to Identify Seamless or ERW Stainless Steel pipes?

To identify that a pipe supplied is seamless or ERW, Simply read the stencil on the side of the pipe. If it is ASTM A53, Type S means seamless. Type F is furnace but welded, type E is Electrical resist welded.

What is the difference between seamless stainless steel pipe and ERW stainless steel pipe?

1. ERW steel pipe is manufactured by rolling metal and then welding it longitudinally across its length. Seamless pipe is manufactured by extruding the metal to the desired length; therefore ERW steel pipe have a welded joint in its cross-section, while seamless pipe does not have any joint in its cross-section through-out its length.

2. In Seamless steel pipe, there are no welding or joints and is manufactured from solid round billets. The seamless pipe is finished to dimensional and wall thickness specifications in sizes from 1/8 inch to 26 inch OD. Applicable in for High-pressure applications such as Hydrocarbon Industries & Refineries, Oil & Gas Exploration & Drilling, Oil & Gas Transportation and Air and Hydraulic cylinders, Bearings, Boilers, Automobiles, etc.

3. ERW steel pipes are welded longitudinally, manufactured from Strip / Coil and can be manufactured upto 24” OD. ERW steel pipe cold formed from a ribbon of steel pulled through a series of rollers and formed into a tube which is fused through a electric charge. It is mainly used for low/ medium pressure applications such as transportation of water / oil.

4. Common sizes for ERW Steel Pipe range from 2 3/8 inch OD to 24 inch OD in a variety of lengths to over 100 feet. Surface finishes are available in bare and coated formats and processing can be handled on site to customer specifications.

The Introduction of ERW Galvanized Steel Pipe

Pipe manufacturer Prime Steel Pipe will introduce ERW galvanized steel pipe for everyone next. What is ERW steel pipe? For pipes size 4 inch (10.2mm) OD and below, strip is fed into a set of forming rolls which consists of horizontal and vertical rollers so placed as to gradually from the flat strip in to a tube which is then allowed to pass the welding electrodes. The electrodes are copper disks connected to the secondary of a revolving transformer assembly. The copper disk electrodes make contact on each side of the seam and temperature is raised to the welding point. Outside flash is removed by a cutting tool as the tube leaves the electrodes, inside flash is removed either by an air hammer or by passing a mandnel through the welded tube after the tube has been cooled. This is termed as Electric Resistance Welded Pipe.

ERW galvanized steel pipes has long been one of the most used building materials in the world. ERW galvanized steel pipes can resist the attack of wild, water & road salts. ERW steel pipes are used in Water Pipelines, Agriculture and Irrigation (Water Mains, Sewerage Systems, Industrial Water Lines, Plant Piping, Deep Tube-Wells & Casing Pipes). Other popular application area includes usage in gas pipe lines (pipe lines for natural gas, LPG and other non-toxic gases).

ERW galvanized steel pipe is steel pipe covered with a protective coating of zinc that greatly reduces its tendency to corrode and extends its life expectancy. It may be used in residential water supply lines, but not gas lines because natural gas causes the zinc to flake off and clog the system. It's not frequently used for water supply lines because the minerals in the water react with the galvanizing material and form scale, which builds up over time and will eventually clog the pipe. ERW galvanized steel pipe during galvanizing, steel is immersed in a molten zinc bath, ensuring a tough, uniform barrier coating. Zinc’s natural corrosion resistance provides long-term protection, even in outdoor environments. Apart from preventing water corrosion, it is also equally effective in dry & indoor environments.

The fitting for ERW galvanized steel pipe is galvanized malleable (soft) cast iron. They connect by screwing onto the threaded pipe, after applying a small amount of pipe joint compound on the threads. Larger diameter pipe is welded rather than threaded.


Differences between Precision Steel Pipe and Seamless Steel Pipe

Precision steel tube is a kind of high precision steel pipe after cold drawing or hot rolling treatment. It is mainly used to produce pneumatic or hydraulic components because of the advantages of high-pressure non-leaking, high precision, high finish, cold bending, The products, such as cylinders or cylinders, are made of seamless steel pipes. Precise seamless steel pipe chemical composition of carbon C, silicon Si, manganese Mn, sulfur S, phosphorus P, chromium Cr.

Welded precision steel tubes are primarily used for structural and media conveying applications due to the high degree of dimensional accuracy of the internal and external diameter – and the stability resulting from that fact.

Precision steel pipes are always the first choice in all cases that involve a high level of dimensional accuracy of outer-, inner diameter or of the wall thickness. They dispose over a smooth surface and provide for targeted mechanical properties. Prime Steel Pipe offers you a comprehensive assortment of seamless or welded precision pipes in the most diverse range of wall thicknesses. We thereby of course, comply with all these specifications and standards. On request, we also take on various processing assignments for our customers.

Differences between precision steel pipe and seamless steel pipe

1. The main feature of seamless steel pipe is welded joints, can withstand greater pressure. The product can be very rough as cast or cold parts. The following are the same as the "
2. Precision steel pipe is the product in recent years, mainly the hole, the outer wall size has strict tolerances and roughness.

Factors Affecting Rust of Stainless Steel Pipe Elbow

Stainless steel pipe elbow has excellent corrosion resistance, stainless steel surface thin and strong oxide film so that all stainless steel in all water quality has excellent corrosion resistance, even buried also has excellent corrosion resistance. So it is suitable for a variety of water quality, in addition to disinfection and sterilization, do not need to control the water quality, at the same time, there is no corrosion and excessive exudate, to maintain clean water quality, to prevent secondary pollution, can withstand up to 30 meters per second the impact of high water flow.

Many people think that stainless steel material is of course not rusty steel, it is true. Stainless steel pipe elbow rust mechanism is the formation of dense alloy oxide film, isolated oxygen contact to prevent the continuation of oxidation. So stainless steel is not "stainless". Stainless steel has the ability to resist atmospheric oxidation --- that is, stainless steel, but also in the acid, alkali, salt medium is the ability to corrosion - that is, corrosion resistance. Following the Prime Steel pipe to understand the impact of stainless steel under the main factors of rust it.

1. The content of alloying elements. In general, the content of chromium in 10.5% steel is not easy to rust. The higher the content of chromium and nickel, the better the corrosion resistance, such as 304 material nickel content of 8-10%, chromium content of 18-20%, such a 304 stainless steel angle in general is not rusty .

2. The manufacturing enterprises of the smelting process will also affect the corrosion resistance of stainless steel. Smelting technology is good, advanced equipment, advanced technology of large 304 stainless steel angle steel plant Whether in the control of alloying elements, impurities removal, billet cooling temperature control can be guaranteed, so the product quality is stable and reliable, inherent quality is good, rust. On the contrary, some small steel plant equipment behind, backward technology, smelting process, impurities can not be removed, the production of products will inevitably rust.

3. The use of environmental chloride ions. Chloride is widely present, such as salt, sweat, sea water, sea breeze, soil and so on. Stainless steel in the presence of chloride ions in the environment, corrosion quickly, even more than ordinary low carbon steel. So the use of stainless steel elbow pipe fittings are required, but also need to always wipe, remove the dust, keep clean and dry.

4. The external environment, the climate is dry and ventilated environment is not easy to rust. And the air humidity, continuous rainy weather, or air containing high degree of acidification of the environment is easy to rust. 304 stainless steel angle steel stainless steel, if the surrounding environment is too bad will be rusty.

In addition, the stainless steel pipe elbow has a rust point, indicating that the elbow is not purely stainless steel material is made, is the type of stainless steel elbow. Rust point can be polished with ultra-fine sandpaper bright colorless paint to do after the anti-rust treatment can be used. If you do not deal with rust point, these rust points will gradually expand, affect the appearance and will shorten the elbow life.


Advantages and Disadvantages of Hot Rolling Seamless Steel Pipe

We have mention the definition of hot rolling seamless steel pipe previously, today, Prime Steel Pipe will continue to talk about the advantages and disadvantages of hot rolling seamless steel tube with all of you.

Advantages of hot rolling seamless steel pipe

Can damage the ingot casting organization, refine the grain of steel, and eliminate the defects of microstructure, so that the steel structure is dense, mechanical properties improved. This improvement is mainly reflected in the rolling direction, so that the steel to a certain extent is no longer an isotropic body; pouring the formation of bubbles, cracks and loose, but also in the high temperature and pressure under the welding.

Disadvantages of hot rolling seamless steel pipe

1. After hot rolling, non-metallic inclusions (mainly sulfides and oxides, as well as silicates) inside the steel are pressed into flakes and delamination (interlayer). Stratification makes the performance of the steel in the thickness direction greatly deteriorated, and there may be tearing occurs when the weld shrinks. The local strain induced by the weld shrinkage often reaches several times the yield point strain, much larger than the load caused by the load;

2. Unstable cooling caused by residual stress. Residual stress is in the absence of external force under the action of internal self-balanced, all kinds of cross-section of hot-rolled steel have such residual stress, the general steel cross-sectional size, the greater the residual stress. Although the residual stress is self-balanced, but the steel components under the action of external force or have a certain impact. Such as deformation, stability, anti-fatigue and other aspects may have a negative effect.

3. Hot-rolled steel products, for the thickness and side width of this bad control. We are familiar with the thermal expansion and contraction, because the beginning of the hot rolled out even if the length of the thickness of the standard, the final cooling or there will be a certain negative difference, the wider the width of the gap, the thicker the more obvious the performance. So for large steel, for the steel side width, thickness, length, angle, and the edge can not be too precise requirements.