Pipe Welding – In the case of welding 2 pipes using pipe welding, it is the best method. In this instance, welders may employ a variety of methods including TIG or arc welding as well as MIG welding to achieve the perfect welding. All of these can be utilized to the pipe welding process, TIG welding is the most commonly used method. For projects that require welding cylindrical tubes of metal and bent metals pipe welding is a good alternative.
The Basics of Pipe Welding
- Make sure you determine the best method prior to.
- Know enough about the security of the method.
- Make sure you wear the correct welding clothing to safeguard yourself from injury.
- Get all your welding supplies ahead of time and clean the welding equipment prior to use.
- Make sure that all materials require grinding, and then bevel the edges that are thicker.
Passes Used in Pipe Welding
1. Root Passes
These are the first steps and are typically used when welding is used to fill in gaps between piping sections. Manual passes can also be the ideal alternative to root passes since they maintain continuity across the welding tack. Welding with gas metal arcs is an additional option to use in place of root passes. The only difference is that it’s an open root weld that does not have the backing rings.
2. Hot Passes
The hot passes can be described as single welding employed to join the root welds through groove faces. When welding in the 2G position, welders are able to split hot passes to get the desired welding. If there is an unusually large root opening welding equipment may break hot passes.
3. Fill Passes
Fill passes are a fantastic way to fill grooves that occur during welding. In certain instances welds create cavities that affect the overall performance of welds. To reduce the impact of these cavities welders are usually required to complete beading to create the strength of the joint. Fill passes are the area of the bead required to be filled with the particular welding joint. The fill pass is created following the root’s passage.
4. Cap Passes
Cap passes serve to fill tops of welding joints. Since they are the minimum amount of building material past the pipe’s surface, welding professionals find these passes beneficial. This is why welders sand down build-up layers in order to increase the beading power and remove any contamination prior to making the final cap passes.
Pipe Welding Positions
1. The Flat (1G) Position
Although not often used by welding workers it is the most common position for welding. The position of the flat (1G) location is by far the common position for welding. When welding in this type of position it is recommended that welders place the workpiece horizontally to ensure greater comfort. When this is done welding is straightforward and easy because the pipe can rotate free away from the welding. To get the most effective welding results the welders should keep their posture fixed when welding at the top of the pipe.
Follow these tips to be able to weld successfully in this manner:
- Start the arcing starting at the tack’s central point.
- Set the gun and pipe parallel to one another. To ensure accuracy, you should use the 5-10 degree dragging angle
- Make sure that the stick you use has a length of 5/8 inch or less.
2. The Horizontal (2G) Welding Position
This is an position for groove welding that requires the welder put the workpiece in an upright position. The welder remains in a fixed posture and joins the workpiece’s horizontal side in this.
3. The 5G Welding Position
Like the flat position 5G welding position makes use of an straight-lined welding pipe. The main difference between the two is the fact that workpiece remains in an unmoved position, and has no flexibility for turning. Welders are able to move workpiece in vertical moves. Welding is performed with the tack’s centre at an angle of 5-10 degrees. Before you make a filling pass, you will grind out the ends and beginnings for greater precision and precision. The filling process is only completed when the root pass is completed.
4. The 6G Welding Position
From all the welding positions that are available, the position of 6G is the most challenging because it requires fixing the workpieces in a 45 degree angle. This process requires the highest level of accuracy and speed since welding takes place in a fixed position.
How to Test Your Welds in Pipe Welding
Tests are conducted to assess the strength as well as their weakness and overall quality. The non-destructive (NDT) is by far the most commonly used method to test. To ensure that the test results are accurate the pipes and welding must be in good condition. Shaking or dismantling the assembly can cause inaccurate results when conducting tests.
Here’s a brief overview of NDT testing techniques:
1. Visual Inspection of the Weld
The name implies the procedure involves observing the whole assembly. It is the most ancient, fastest and most affordable inspection method using NDT. Its effectiveness is based on the welder’s vision. Most of the time this method is employed to find physical defects that could cause a weld’s failure. However, this method is not ideal to test internal flaws.
2. X-Ray Testing
Testing with X-rays is the most efficient NDT technique to employ when conducting tests to determine the presence of internal flaws and defects in the structure. It is the best method for testing high-quality , delicate welds. In addition to being efficient however, it is also the most expensive and requires a high level of expertise in the conducting tests.
3. Fillet Break Test
The test of fillet break is the most reliable test to determine root penetration and for analyzing possible defects in the assemblies. The majority of welders test in the middle and at the final stage of welding. If the weld is bent without breakage, it indicates that the welds are sturdy and can pass the test. The only exceptions for this test are fractures and cracks that do not exceed 10 millimeters.
4. The Liquid Dye Penetration Test
The test of penetration using liquid dye involves applying a liquid dye to the surface of the weld. Usually, the dye is then removed before setting the welding assembly for drying in a dry, cool and clean area. When the dryness is completely gone the damaged parts will be evident. When compared to the visual inspectionmethod, using the penetration of liquid dye method is the most efficient.
5. Macro Etch Testing
The method of testing macro etch involves cutting a piece of a joint that is welding and testing it. The test is conducted using an acidic liquid on the test sample and then observing the reaction. The reaction causes obvious visibility of the macro-structural flaws. The most common defects that can be identified using this method include mold slag, grain-size hydrogen flakes, porosity or mold slag.
6. The Bend Test
The bend test is a method of stretching the specimen at an angle of 180 degrees to determine the strength of the joint to breakage. Tension force is generally applied to the joints’ facades and the foundation to determine the strength and quality of the joint.
Common Mistakes in Pipe Welding
No matter how skilled and cautious a welder might be, there are always mistakes when it comes to pipe welding. Welders who are beginners as well as experienced professionals are prone to making welding mistakes. Here are some common errors and ways to reduce their impact.
1. Aligning the Parts Wrongly
The process of putting the welds in place is a common practice in welding. The biggest mistake that welding professionals make is hurrying to the welding process while failing to align the parts or skipping them. This can result in sharp bevels. For avoiding this problem, be sure you have a proper fit for the pieces prior to the fusion process.
2. Porosity
If gases like hydrogen, oxygen, or nitrogen are introduced to enter the welding pool, the likelihood is that porosity will be observed. Porosity can occur as the result of a temporary interruption that occurs in gas shielding. If this happens it is necessary to make use of additional shielding gas. This can lead to an increase in the time for welding and a decrease in overall weld quality. To reduce the risk of porosity, wash and sanitize the workpieces prior welding.
3. Undercutting
Cutting is one of the most common causes of low quality welding. It’s the result of excessive tensions, long-arcs improper angling, and uneven workspaces. By examining these aspects, you can eliminate any chances of undercutting, and it increases the production of quality welds.
4. Cracks
Cracks that develop on your welds can affect the quality of the product. Cracks typically occur because of contamination the porosity of the material, its rapid cooling as well as pressure imbalance. Repairing them is an overwhelming task since it requires repeating the whole welding procedure.
To prevent cracks, use:
- Cleanse the edges of the plate for a more natural fit
- You can do this by putting it in the right temperature.
- Make sure that the surface of the material is properly sanded prior to welding.
1. Inclusion of Slag
Slags from welding are the result of welding processes, usually caused by the coating of flux. While slags play an important role in preventing the formation of oxidation during the fusion joints, welders need to eliminate the slags to make room for the next step. To prevent the formation of slag increase the speed of welding and angle and then verify the welding current.
2. Poor Preparation
The preparation prior to welding is essential to have a successful pipe weld experience:
- Installation of the parts to ensure the correct alignment
- Clean and disinfect the workpieces
- Get ready in the proper welding clothing
- All welding equipment and machinery in an organized area
- Verify the amount of gas used to shield the area.
Conclusion: How To Pipe Weld
Pipe welding is an method that demands precision and experience. The process can range from basic processes like ventilating the work areas to the more complicated ones like installing the equipment. A lack of preparation time can lead to the waste of crucial welding materials.