Hollow devices used to transmit liquid, gas, steam, etc. are called pipes.
You will get efficient and thoughtful service from Nearyz Resources.
Pipes are produced from different materials, depending on the place they are used and the characteristics of the fluid that will pass through them. These can be categorized as:
Welding to pipes also must be applied in order to obtain practical end-products. This blog post will explain this welding process as a whole.
Pre-preparation of the pipes before welding improves the quality of the weld seam, ensures its physical appearance and economical work. In the preparation stage for welding, preparation is made by paying attention to the thickness of the part, the appropriate welding mouth, and the smoothness of the equipment.
The following procedure is followed for the preparation of welding to pipes.
For pipes with a wall thickness of more than 4 mm, the weld mouth is opened in order to increase penetration. Small diameter pipes can be welded with files, pipe cutters, grinders, and oxy gas.
During the spotting of the pipes, a &#;V&#; bed is used to ensure that the axes are opposite each other and remain stable during welding. In special cases, angle iron is also used.
Fig.2: Centering of Pipes Fig.2: Centering Process SequenceThe mouths of the pipes of the same diameter, which are cut and to be joined at welding, are cleaned. There should be no axial misalignment in the pipes to be joined by welding. Otherwise, welding to pipes might not be performed correctly.
Fig.3: Opening welding bentFig.4: Preparation of WeldsThe ends of the pipes are lapped so that all sides are equal. Pipes with a wall thickness of up to 3 mm are welded by leaving some space between them (approximately half the wall thickness). The machine is started and the amperage is adjusted. It is centered on four sides with its axes aligned, and the slag of the centers is cleaned with a welding hammer or wire brushes. Welding is done starting from this point.
The area formed between two pieces that intersect each other is called a cross-section. In the welding to pipes intersecting, before welding, the pipes must be lapped together to form a cross-section using various monitoring tools (saw, drill, file, etc.).
Before starting the &#;T&#; welding to pipes, it is lapped with half-round and round files so that the upper pipe fits into the lower pipe. The cross-section of the lower pipe is drilled with a drill, starting with a small diameter gradually. The lower tube hole is ovalized so that the upper tube is fully joined.
Fig.5: Motion of ElectrosFig.6: HarmonyFig.7: Marking and Lapping of PipesFig.8: T Joint Intersection CreationIn joining welds, it is very important to lap the parts together and create axes and directions. Axes and angles to be created must be checked before the parts are centered. The contact points created in the lapping of the parts are one of the important factors affecting the weld seam. The weld gap to be left between the weld joints increases the strength of the weld seam. The penetration is increased by leaving a welding gap of half the pipe wall thickness.
One of the most important stages of the preparation of the pipes for welding is the centering of the pipes. Centering should be done in the direction of the axes at the joints. After the centering process for joining the pipes, the axial deviations that occur due to the welding shrinkage in the parts should be brought to the square.
The welding to pipes must ensure impermeability. Especially in hydraulic, pneumatic, natural gas, and heating systems, sealing is important. Welds are checked with compressed air and water.
It is very important to control the molten bath during welding, as invisible pores and slag will cause leaks in welded joints. During welding, the welding electrode angle is different at each point. For this reason, the electrode should be held at an angle of 75 &#; 80&#; to the instrument surface. It is a must for successful welding to pipes.
In horizontal welding of pipes, the electrode is started from the upper point and welded by turning. It should be welded without any gaps at the start and endpoints of the electrode. In electric arc welding, sufficient curvature temperature is achieved with amperage setting and the use of appropriate electrodes.
The arc length should be equal to the diameter of the electrode. It is very important to keep this distance under control by the welder depending on the electrode spinning speed. Welding speed is also one of the important factors affecting the shape and penetration of the weld seam. Increasing the speed causes a decrease in the width of the weld seam and a decrease in penetration. The decrease in the welding speed causes the weld seam to pile up.
While the welding to pipes is being completed, the entire perimeter seam should be completed by cleaning the slag at the endpoints of the seam and maintaining the welding parameters. The welding joint should be cleaned with steel wire brushes as the gases emitted during the combustion of the electrode will cause corrosion by combining with the humidity of the air around the weld joint area.
The pipes must be cut in the dimensions and position of the place to be installed. Commonly used cutting methods; with oxy gas, cutting electrodes, plasma, cutter of a hand grinder, band and hydraulic saws, cutting tools, etc. done by methods.
As a result of cutting operations, burrs can form inside the pipes. For the burrs not to cause blockages in future operations like performing welding to pipes, burrs and foreign matter (oil, rust, paint) residues must be cleaned. To clean them, it is necessary to use chisels, files, hand, and stationary grinders, wire brushes, and sandpapers, and chemicals. For the strength of the weld, no foreign matter residue should be left.
The cut and cleaned pipes must be lapped together before being welded. Otherwise, welding errors may be encountered. To do the lapping process, we can use the machines usually utilized for weld beveling and cleaning.
The company is the world’s best Welded Pipe supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.
Welding to pipes is not always done end-to-end (linearly). Pipes are laid in ways such as angled turns in different directions, the intersection of pipes coming from different directions, and the joining of pipes of different diameters. In such cases, it is necessary to remove the intersection. Pipes with a wall thickness of more than 5 mm must also be welded. In such cases, we use special beveling methods. The value of the bevel angle is between 50-90˚.
After the preparations for cutting, cleaning, lapping, and beveling are made, the parts centered on the V bed are drawn in a horizontal position by giving appropriate spacing (The root seam can be drawn in TIG welding). Then, after the slag is cleaned, the other passes are drawn.
When centering, a template is used between two parts. The parts are neatly centered and evenly spaced.
Fig.9-10: The sequence of operations in welding pipesThe root seam is pulled (could be TIG welding.) The second pass of the weld is cut and cleared.
Pipes sometimes need to be detachably connected to pumps, boilers, or each other. Welding is one of the non-removable joints, so flanges are welded to the places where the pipes are to be removed and the flanges are connected with bolts. When maintenance or replacement is to be made on the piping systems, the flanges are removed from their bolts and necessary work is done.
In this article we will discuss the various types and process involved in welding pipe manufacturing.Steel pipes are produced mainly by two distinct manufacturing methods which result in either a welded steel pipe or seamless steel pipe.
Welded steel pipe(also known as welded pipe) is made of steel plate or steel strip after crimping,generally fixed length of 6 meters.Welding pipe production process is simple,high production efficiency,variety specifications, less equipment investment,but generally welded pipe less than the strength of seamless pipe.
In the API 5L standard,there are usually the following welding pipes:
Electric resistance welded (ERW) pipe is manufactured by cold-forming a sheet of steel into a cylindrical shape. Current is then passed between the two edges of the steel to heat the steel to a point at which the edges are forced together to form a bond without the use of welding filler material.Electric resistance weld pipe is normally produced in sizes from 2% inch 00 NPS 2 thru 24 inch 00. (NPS 24)
ERW including high frequency welded steel pipe(HFW) and low frequency welded steel pipe(LFW).Over time, the welds of low frequency ERW pipe was found to be susceptible to selective seam corrosion,hook cracks,and inadequate bonding of the seams,so low frequency ERW is no longer used to manufacture pipe.The high frequency process is still being used to manufacture pipe for use in new pipeline construction.
Laser welding is a non-contact process which requires access to the weld zone from only one side of the parts being welded.Laser welding attributes are particularly important in the production of austenitic,ferritic,and duplex stainless steel used in the automotive,aerospace,food processing,medical,oil and gas,and chemical industries.
Continuous welded pipes,referring to small diameter products manufactured using continuous welding process, are primarily utilized for supply of water and gas at lower costs and higher productivity. Continuous welded pipes are considered as the lowest cost variants among all steel pipes, and find use in structural applications, plumbing applications, and other low pressure applications.Continuous weld pipe is produced in sizes from NPS Va to NPS 4.
Submerged arc welding (SAW) process involves formation of an arc between a continuously fed bare wire electrode and the work-piece.
There are two types of submerged arc welding (SAW) processes:Longitudinal Submerged Arc Welding (LSAW) ,Spiral Submerged Arc Welding (SSAW).
The longitudinal submerged arc welding(LSAW) steel pipe diameter range is larger than ERW,normally from 16 inch to 60 inch, 406mm to mm. Good performances on high pressure resistance,and low-temperature corrosion resistance.
Spiral submerged arc welding (SSAW) steel pipe,also called HSAW pipe,welding line shape like a helix.It is using the same welding technology of Submerged Arc-Welding with LSAW pipe.Differently SSAW pipe is spiral welded where the LSAW is longitudinally welded.Manufacturing process is rolling the steel strip,to make the rolling direction have an angle with the direction of the pipe center,forming and welding, so the welding seam is in a spiral line.The SSAW pipe diameter range is from 20 inch to 100 inch, 406 mm to mm.
The technological process of welding pipes:
Uncoil the raw materials &#; surface flatness &#; end cutting and welding- looping- forming -welding- remove the welding bead &#; pre-correction &#; induction heat treatment- sizing block and correction &#; eddy current testing- cutting-hydraulic pressure testing- pickling- final inspection (strictly) &#; packaging &#; shipments.
Haihao Group has been specializing in the production of steel pipes more than 30 years,we can supply all types welded pipes in high quality.For more information,feel free to contact us :
Are you interested in learning more about Straight Seam Welded Pipe? Contact us today to secure an expert consultation!