It is crucial for welders to understand various welding techniques. Heliarc welding is one of the most used types of welding. Heliarc welding may be confusing to some people.
What exactly is heliarc welding?
Let’s read the article that follows to discover the answer.
What is Heliarc Welding?
Welding Tungsten Inert Gas (TIG) or Gas Tungsten Arc Welding (GTAW) was first discovered in 1940 in the USA.
This welding doesn’t need any additional flux or welding wire layers to protect the junction.
Almost all types of metal can have high-quality welds created with GTAW.
Components Required for TIG Welding
GTAW is typically applied to stainless steel and other light metals like magnesium, aluminum, etc.
Significant skills are also required for this welding procedure to produce good results.
The components required for TIG welding are:
1. Power Source
Tig Welding uses a constant current source. This ensures relatively constant heat.
TIG’s electrical polarity depends on the application. Two modes are used: positive and negatively charged electrodes.
Negatively charged welding electrodes are used for welding steel, nickel, titanium, and other metals.
Positively charged electrodes are used for shallow welds (less heat is generated on the workpiece).
TIG welding requires both DC and AC electric power.
The arc flame and heater are created using electricity, while the other supporting components are still obtained or provided by other tools.
Aluminum, magnesium, cast iron, and other metal forms are frequently joined together by alternating current (AC) welding.
During direct current welding, direct polarity is frequently used to join materials like steel, stainless steel, and copper alloys.
The Torch offers an automated and manual setting.
In general, welding torches have a handle, whereas those that are automatic have a mounting rack.
A non-consumable tungsten electrode, a compartment for the shielding gas, and a conductive alloy are all found inside the welding torch.
The components of welding torches are constructed of plastic insulation.
In manual welding, the electrode tip is typically grounded at an angle between 60 and 90 degrees, regardless of electrode diameter.
The tip angle determines the arc’s form and impacts the weld pool’s penetration profile in mechanical applications.
It is important to verify the condition between the welds and grind the edges consistently. The electrode for AC current is made entirely of tungsten.
Due to the heat produced in the electrode during the electrode’s positive half-cycle, the tip typically takes on a spherical contour.
In this welding, tungsten is a common inert gas.
When it comes to shielding the weld region from ambient air, tungsten works well. Co2 (not inert) is now commonly used since it is more affordable and steady in price.
Argon gas cylinders or other gas is a supporting equipment used in this TIG welding.
The gas has a role in shielding the welding process from the effects of ambient air.
5. Backing System
In order to weld pipes, a backing system is necessary.
Hence the length and diameter of the pipe affect the pre-weld time. A minimum of five volume changes must occur before welding.
Thus, the speed and purge time is currently adjusted to ensure that.
6. Welded Workpiece or Material
The substance that goes through the welding process is known as the workpiece.
The workpiece is linked to ground electricity for gas tungsten arc welding.
Common metals to be welded using TIG welding:
- Carbon and Low alloy steels
- Stainless steels 304, 316,321. 17-4, 410
- Nickel alloys Inconel, Hastelloy, Waspalloy etc.
- Aluminum alloys, 3003, 5052, 6061
- Magnesium alloys Titanium Cobalt alloys Haynes 188, and L605
- Refractory alloys columbium, molybdenum, tungsten Copper alloys aluminum bronze , nibral bronze, pure copper
The stages of the TIG welding process are as follows:
- Make sure the main cable of the welding machine is properly attached to the power source.
- When installing the main cable at the current source, the condition of the welding machine must be OFF.
- Do a check on: Cooling duct.
- Gas pressure gas mixture volume
- Set the amount of current, for example 240 amperes
- Set the flow of shielding gas eg 120 liters/minute
- Wear work safety equipment, such as helmet + goggles, gloves and welding clothes.
- Prepare the workpiece on the workbench
- Clamp the mass pliers on the workpiece or work table tightly.
- Generate the initial arc by scratching the tip of the tungsten electrode on the workpiece (Striking Of Arc), until you get a stable arc.
- Maintaining a 1.5 mm to 3 mm gap between the electrode’s tip and the workpiece’s surface will provide a stable arc.
- This distance setting also applies to semi-automatic or fully automatic.
- The position of torch is held at an angle of 60-85 degrees. Then the filler metal is fed from the outside in a circular motion to fill the weld seam to form welding ridges.
Pros and Cons of Heliarc Welding
Here are some points of the advantages of heliarc welding:
- Can achieve high-quality welding outcomes on both ferrous and non-ferrous materials.
- Several contaminants in the air can lower the weld’s quality. All of the contaminants can be eliminated if the welding method is done correctly.
- It is possible to use a single side on many different materials to produce excellent root passes.
- It is simpler to manage the weld metal during coalescing and filling with TIG/GTAW because its speed is slower than SMAW’s.
Here are some disadvantages of heliarc welding:
- TIG/GTAW fill rates are less than those of other welding techniques.
- Closer control of joint alignment is needed for welding from one side to generate welds of excellent quality.
- Better connection cleanliness is necessary for TIG/GTAW in order to prevent gas flaws and porosity.
- Extra care must be taken to keep an inert gas barrier over the weld crater at airspeeds greater than 5 mph.
Heliarc welding is a process that uses tungsten electrodes (non-consumable tungsten).
A gas-based covering, often made of argon, helium, or a combination of the two, protects or covers the welding area.
Argon is often used in this welding because it is heavier than air and can produce better welding covering areas.
The most common application of TIG/GTAW welding is to weld metals like magnesium, titanium, and aluminum that are reactive to oxygen gas.
Plates with a thickness of up to 5 mm are frequently subjected to TIG/GTAW welding.