What is purge in TIG welding?
Back purging is the act of removing all undesirable gasses and vapours from the backside of your welding surface by replacing the atmosphere with Argon, leaving your weld contaminant-free making it clean, smooth & looking like the front side of the weld.
Do you have to purge stainless pipe?
Welding stainless steel tubes and pipes typically requires back purging with argon gas when using traditional processes, such as gas tungsten arc welding (GTAW) and shielded metal arc welding (SMAW).
Do you need to back purge aluminum?
purging will help aluminum weld better in open root situations but is not always needed or called for. but stainless steel open butt welds need a back purge because of the granulation that occurs on the back side that is a surface flaw and also causes loss of corrosion resistance.
Why do you back purge stainless steel?
Back purging is the process of shielding the inside of the weld with an inert gas to prevent contamination during the welding process, resulting in a stronger weld. An inert gas does not undergo chemical reactions and prevents rapid oxidation while the stainless is in a molten state.
Can you purge stainless with nitrogen?
Nitrogen has been used as a purge gas but is unsuitable for some stainless steels. The most common way to remove gas from the weld zone is to flush it away with an inert gas. The weld zone can be contained to prevent fresh gas from entering once the contained volume has been purged.
Why is purging important?
Purging ensures that you have control over which gases are in your gas delivery system, and therefore which gases are being exposed to internal components, sensors, or other equipment. It also helps to prevent unwanted reactions from taking place, which can greatly increase the service life of related components.
Can you weld stainless pipe without purge?
304 stainless steel can be successfully welded using the Regulated Metal Deposition (RMD™) process without a back purge. This is not true for duplex stainless steels. These must be purged with an inert gas such as argon.
What is argon purging?
Argon Purging Systems (APS), applicable to purging induction melting furnaces and induction power ladle systems, help to reduce metallic inclusions to improve the overall purity of the melt. These systems are an economical way to produce alloy steels.
What gas do you use to purge stainless steel?
Argon
Argon is generally used for this purpose but helium is an alternative depending on gas cost and availability. Nitrogen has been used as a purge gas but is unsuitable for some stainless steels. Purge gases must be of a certain quality, in order that the welds are made correctly.
Why argon is used for purging?
Argon is a denser gas than nitrogen, and an industrial application purged using argon will keep moisture and oxygen out more effectively as a result. Its molecules will disperse less easily than with nitrogen.
Why purging is done with nitrogen?
The benefits of nitrogen purging are numerous, but the most crucial reasons for nitrogen gas purging are to prevent chemical alteration of products and to prevent moisture-related equipment damage or even combustion.
What to do after purging?
rinse your mouth with a non-acidic mouthwash. make sure you see your dentist regularly. do not drink or eat acidic foods, such as fruit juice, during a binge and after purging. do not smoke.
How to check back purge flow in TIG machine?
1. While not welding (and not in pre or post flow), the solenoid in the TIG machine is closed. Read the flowmeter. It will indicate the back purge flow. 2. Next, trigger the pre-flow and read the flowmeter again. When the solenoid is triggered, the total flow will increase. The difference between the second and first read is the TIG cup flow.
Why is purging so important in TIG welding?
Purging is the process of removing the oxygen from the inside of an enclosed part prior to TIG welding. Removing oxygen from inside the part protects the back of the weld from oxidation due to the high heat of TIG welding. Before we discuss how to purge, let’s explore why purging is important. Why Purging Is Needed
What do you need for back purging welding?
A better joint fit now will further ensure your weld and especially your back purge is durable and smooth. You’ll need a plug with a tube attachment to connect one end to the gas tank. On the other end, you will need a dam of some sort. The dam can be just about anything.
Can a T IG welding setup produce beautiful welds?
T ig welding can produce beautiful looking welds, and more importantly, x-ray quality deposits on some of the most critical welding applications. For the beginner it may be a very intimidating process. Selecting the right tungsten (type and size), cup size, and shielding gas and gas flow can be a daunting task.
