Welding is an important manufacturing process for all industries whose applications rely on sturdy and strong metal components and structures.
Its purpose is to help hold adjoining metal parts together, thus increasing their functional output and protecting their physical and mechanical properties.
Inconel, a type of nickel-based alloys known for their high corrosion resistance, temperature resistance, and tensile strength, requires welding procedures.
Welding enables the alloys to better withstand the harsh conditions (high temperature, high stress) found in a variety of industrial settings.
However, since Inconel alloys have such a high melting point, it is not always possible to weld them to perfection using standard welding procedures.
Therefore, the following guide will cover three tips that will ensure that your Inconel parts don’t get damaged or lose their properties and functionality during welding.
Why would automation greatly enhance Inconel welding?
Automated welding (a.k.a. robotic welding) is safer, faster, and more accurate than traditional manual welding methods.
Further details about the benefits of automated welding are listed below:
| Safety | machines limit the possibility of accidents from occurring—robots can’t get injured. |
| Speed | higher weld volumes can be achieved through continuous automated operations. |
| Quality | gaps, blemishes, and other weld distortions are mitigated due to tight tolerance programming. |
| Consistency | welding robots produce consistent identical welds which help increase production levels. |
| Cost | increased efficiency, lower material wastage, and reduced labor costs offset any upfront costs associated with robotic equipment purchases over time. |
While all the previously-listed benefits of automated welding give a strong case for using it over manual welding methods when it comes to Inconel welds, perhaps the most convincing one is the ability to weld at high temperatures—a necessary process for welding Inconel alloys since they are so heat-resistant.
While high-heat welds often cause surface damage (cracks) to welded metals and alloys, the chance of potential destruction to both welding tools and welded metals is significantly reduced with automated welding.
The robots can maintain a constant welding temperature that does not exceed the damage level for all forms of manufacturing material, including Inconel alloys.
Although not all automated welding methods work well with Inconel, there are a couple that can handle its unique composition and set of properties (strength and heat resistance).
Plasma arc welding, for example, uses a welding arc that is tighter and more focused than other automated welding processes.
The focused arc helps to distribute heat more evenly among welded material, reducing any chances of damage.
It also allows for higher proximity between the welding tool, which helps increase sinking heat (cooling rate).
Pulsed micro welding is another automated welding procedure that is ideal for welding Inconel as it takes care of a variety of problems associated with manual high-heat welds.
It reduces heat, increases productivity, and lowers wastage (splatter and fume).
Tungsten Inert Gas (TIG) welding is an all-purpose welding method that can weld all metals and metal alloys with a precision not commonly found in other welding procedures.
The TIG welding technique can weld aluminum, magnesium, copper, stainless steel, and a host of alloys—including nickel-based alloys like Inconel.
Since it can weld various types of metals and alloys together, it is extremely useful for Inconel-based applications that utilize other metals to enhance their physical properties and mechanical functions.
What is more, the technique utilizes a tungsten heating element (electrode) that does not burn or damage during high-heat welds.
Those are necessary to join Inconel alloys and other metals together.
Tungsten has the highest melting point of any metal (6,192 Fahrenheit / 3,422 Celsius).
The TIG technique also uses several different forms of inert gas to protect the weld pool (molten area) from contaminants like oxygen and nitrogen, which typically cause porosity (holes) and splatter in welded areas.
Finally, the TIG technique is completely compatible with the automated plasma arc welding system as the latter relies upon argon (inert gas) to protect it from contaminants.
It also uses a tungsten electrode that can withstand the extremely hot temperatures (up to 50,000 Fahrenheit / 28,000 Celsius) produced by this automated welding process.
Using plasma arc welding with the TIG technique helps create an extremely strong weld that has an aesthetic look without causing any heat damage in the process.
The benefits of combining an automated welding system along with the TIG technique can be further enhanced by utilizing a specific grade of Inconel as a filler material.
All welding processes should use a filler material.
A filler material is nothing more than heated metal (alloys and non-alloys) that flows into the joint space between two metal parts.
The reason filler metals are so important in the welding process is that they reduce the level of incorrect fit-up (distance between metal parts) and thus secure the joint weld more thoroughly.
Filler metals help control the welding process even if the materials being used are not easily welded.
A variety of metals can be used as filler material. Some of the more popular ones include:
However, Inconel 625 is the most suitable filler material for welding Inconel, since other welding metals like the ones listed above do not match any of the Inconel grades that are commonly used as a manufacturing material.
Utilizing a filler metal that is dissimilar to the metals being welded together will often cause a host of problems like galvanic corrosion and extreme volume expansion during hot welds.
Inconel 625 also has excellent corrosion-resistant properties which help eliminate oxidation that occurs due to the excessive heat produced by the TIG method.
In summation, using Inconel as a filler material combined with the automated welding process and the TIG technique will ensure a closer and more secure weld and limit the possibility of corrosive damage.
It is difficult to weld Inconel alloys as their resistance to high temperatures, while ideal for industrial applications working in hot environments, is incompatible with many welding procedures.
Since welding Inconel must be done at the highest temperatures possible to melt metal edges thoroughly enough to fit two parts together, it is important to implement the right welding processes, techniques, and materials.
Only this will ensure that proper joints are formed while welding Inconel alloys.
If the correct welding processes and tooling are not used, cracking, splattering, and other damages may occur that disrupt joint security and mobility.
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From a contract manufacturing firm, BuntyLLC evolved into a full service custom machined, forged and cast metal parts fabrication enterprise. We supply global solutions from our headquarters in Greenville, South Carolina.
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