How To Purge Stainless Steel For Welding? [A Complete Guide]

How To Purge Stainless Steel For Welding

Purging stainless steel is an important step before welding. It helps your weld to be stronger and long-lasting. But, if you do not know how to purge stainless steel for welding, continue the article. Here I will share the exact process with you.

To purge stainless steel, you first need to cut it in the right amount. Then you have to seal it. Once the metal is sealed, you can purge it using helium or argon gas. Purification will release the oxygen accumulated inside it, making your welding work easier.

Since it is a little hard work, you need to read the whole process carefully. Here I will tell you the easiest purification method for welding. If you have the essential equipment, you can get started quickly. Let’s follow the steps below to collect and purge the material and complete the steps accordingly.

10 Easy Steps To Purge Stainless Steel For Welding:

It is important to purge the metal before welding stainless steel. So, if you are a welder, you need to know the process. You can eliminate the gas from the welded joint that can affect the welding by purging. Here I will discuss the purging process in 10 easy steps. Hopefully, these steps will be helpful in your welding profession. 

Step-1: Assemble Necessary Equipment

It is important to assemble the necessary materials to purge stainless steel for welding. If you are a professional, these materials are familiar to you. But for a new welder, it is vital to know what they require. So, here is a list of the necessary equipment to purge stainless steel for welding.

• Welder saw

• File

• Purge plug

• Argon

•Welding hood

Step-2: Cut The Pipe

After assembling all the necessary materials, you need to prepare the pipe. Ensure there is a right cut in the pipe. If the pipe is not cut properly, it will not fit well. This can cause damage to the pipe by debris entering the pipe. So, re-measure it after cutting the pipe and make sure it is cut correctly. Pipes cut to the correct size will allow you to do bomb welding.

Step-3: File The Pipe

Once the pipe is cut to the correct size, it needs to be secured. There are small burrs left on the pipe when you cut it with a saw. Now fill the pipe and fit up to improve the fit-up. It will remove small spots and stains from the saw. This will keep the surface of your pipe clean and flawless, making it very easy to fit.

Step-4: Seal Up Inside Of The Pipe

Before cleaning the pipe for welding, it is important to seal it so that oxygen does not return. You can seal the small pieces using a stiff cover. Cape has a tight cover at one end of the pipe and fittings at the other. Now you can attach the gas hose to protect the inert gas from oxygenation during welding.

Step-5: Flow The Argon

Now flow the argon properly to fill the pipe. Since argon cannot flow fast, it is necessary to wait some time for air pressure to come out of the open hole on the other side before welding. This is the correct rule for the flow of argon. If you spill excess argon, it can leak out, so following the right rules is important. Also, if not enough argon flows that will not make sugar in the weld, and the welding will fail.

Step-6: Fit-Up

Fit-up is more important than welding. If the fit-up is not right, it will never be good to weld. So, it would be best to make sure that there is suitable flowing argon through the pipe at this stage. For proper fit-up, make sure the pipe runs smoothly, and there are no highs and lows. To do this, confirm there are no obstructions in the area where the pipes meet.

Step-7: Tack Weld

Once the pipes are fitted up, place three or four small tacks around the perimeter. The tacks must be properly assembled and have one tack per foot. However, no extra tack can be done. Since there is no purifying gas inside the pipe, it can give a small amount of sugar which is not a problem. Make another tack around the other end to pour the pipe. Four tacks may be required after three to cast large pipes.

Step-8: Purge The Oxygen Zone

At this stage, you need to clear the oxygen zone. You can use argon or helium. Since argon is less expensive than helium, it is better to use argon. However, helium can conduct arc heat better than argon. If your metal is thick, helium will work faster for you. However, carbon dioxide should never be used for stainless casting as it can react.

Step-9: Welding

Your stainless steel is ready for welding, and you can put a fire joint on it. If your stainless steel is properly purged, there are no more barriers to welding. Now, its welding will be stronger and more durable.

Step-10: Inspection The Purging

Once the welding is done properly, you will need to inspect it again. This will allow you to find out if any faults need to be modified. If there is a mistake, it will flop your welding and cost time and money. So, inspect whether every work has been done properly. 

5 Important Tips For Purge Stainless Steel For Welding:

It is important to purify the stainless steel before welding. It is also important for metals other than stainless steel, making it easier to weld and stronger. When you purge stainless steel for welding, there are a few tips to consider. Below I share a few important pieces of advice that may be cooperative for you.

Tip-1: Wear a welding helmet when purging stainless steel for welding. If you have a welded helmet, wear it before purging the metal. It will protect you from unwanted damage. Various chemical products are used in metal purging, which can cause eye damage. However, if you wear your welded helmet, you can avoid this damage.

Tip-2: It is significant to cut the pipe to an accurate size before purging. So first, cut the pipe to a certain size with the help of a measuring instrument. Gloves must be worn on the hands when cutting the pipe. There is no opportunity to cut the hand from the pipe. You should also wear a welded helmet or a pair of safety sunglasses at this time. This will prevent the pipe debris from entering your eyes.

Tip-3: If you do not use the right gas to purge stainless steel, it can mix with dust and cause chemical reactions. You can use argon or helium. However, never use carbon dioxide. It can damage your metal and the atmosphere. You also need to keep in mind the proper use of gas and personal safety at this time.

Tip-4: It would be best if you sealed the pipes properly before welding. Otherwise, the welding will not be long-lasting. And before sealing, make sure that the joint of the pipe is smooth. Then use the stiff cover to seal the pipe joints.

Tip-5: Inspect the entire process before the metal is refined and welded. If you find any problem, repair it before welding. Because, If the purging is not correct, you will not be able to succeed in the welding activity. So it is important to inspect the purification process once.

Frequently Asked Question:

What Is Purging In Welding?

Purging is the oxygen-removing process from stainless steel. This removes oxygen from the sealed metal before welding. It is important to develop a perfect welding environment before welding any other material, including stainless steel. The whole process of welding equipment needs to be protected under air.

It is cleaned to protect the air; otherwise, it may oxidize. Purging results in the oxygen slowly coming out and maintaining slightly higher energy inside the pure chamber. Thus, completely preparing stainless steel for welding is called purging.

Why Is Purging Necessary In Welding?

Metals and airborne oxygen react together as a lot of heat is generated during welding. The oxidation will be the cause of worse and softer welding. The metal is purged before welding to protect it from such damage.

Unprotected welding is prone to cracks, so an inert gas flows over the weld, not interfering with the joint. These protect the welder from possible damage by expelling oxygen from the pipe joints. So, I think oxygen should be purified from each metal before welding. 

Can You Weld Stainless Without Purge?

It would be best if you purged stainless steel before welding. However, if your metal is 304 stainless steel, it can only be welded using a regulated metal deposition process. You do not need to purge this steel to be welded.

However, to weld duplex stainless steel, you must purge it. Otherwise, its welding will not be strong. If the oxygen is stuck inside the stainless-steel pipe, its welding will not be correct. So, I recommend purging the stainless steel before welding. 

What Gas Is Right To Use To Purge Stainless Steel?

Helium is the best gas for purging stainless steel. However, it is more costly than argon and cannot be used by everyone. But if you want to use the best purifying ingredients, this is the right choice for you. Argon is the most useable gas for purging stainless steel. 

Argon uses gas most for a purge because it is less expensive than argon helium. However, the amount of gas you use should be accurate. This is because if the quantity is more or less, it can seriously affect your welding.

Why Is Purging Necessary For Stainless Steel?

Through purging, you can prevent the oxidation of your stainless steel. This prepares your metal for proper welding. By purging, you can avoid tube and pipe discoloration and weld under bead separation. You can also clean the stainless steel inside using inert gas and complete the welding easily.

If you have decided to weld duplex stainless steel, you must purge it. As a result, you can make the welding work easier and take less time. Due to this process, there is no oxygen inside your pipe, so the welding is stronger.

Which Gas Is Not Used In Purging?

Many people use the wrong gas when purging stainless steel, and their welding may fail. The most unsuitable gas for welding is nitrogen and carbon dioxide. These gases can contact two light metals and cause chemical reactions.

Since inert gas is important to purge stainless steel, refrain from using these two glasses. You can use argon gas at a low cost, which is a good choice. You can also use helium if your budget is high.

What Is Back Purging In Welding?

Back purging is the removal of unwanted gas and vapor from the back of the welded surface. Back purging replaces the atmosphere with argon. This allows you to clean and weld your welds. You can make your back welds look like the front with back purging. 

Back purging prevents corrosion from heated, reactive welding. The argon is cast on the outside to prevent the inner part of the welded putty from being “sugared.” Back purging is performed to prevent contamination. However, if it is impossible to get to the root of the casting, you will need to clear the root. It is suitable for low alloy steel and carbon. 


Hopefully, after reading this, you know how to clean stainless steel for welding. By following the shown procedure, you will do this job very easily and successfully. After wearing this article, you will not find it difficult to purify stainless steel.

If you want to get the job done by following these steps, you must follow the tips given above. The tips given here will protect you from the unintended consequences of purging.

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Kaosar Ahmed

This is Kaosar Ahmed. I’m the main publisher of this blog. Welding Leader is a blog where I share welding tips and tricks, reviews, and guides. Stay tuned to get more helpful articles!

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