how to weld stainless steel

How to Weld Stainless Steel with MIG, TIG and MMA

Before we can look at welding stainless steel, it is essential that we first offer a description of what stainless steel is. Stainless steel refers to an iron base material class with some resistance to corrosion and rusting due to chromium’s presence in its composition. 

Chromium helps produce a waterproof and tough chromium oxide layer on the surface of the material. You must be aware stainless steel represents a wide variety of materials. Stainless steel has a low thermal conductivity, meaning that heat energy will not be dispersed quickly from the welding zone. 

This article will be looking at how to weld stainless steel together with the right processes. 

MIG Welding

It is possible to MIG weld stainless steel. However, just like any other welding process, it is essential to ensure you know how to weld stainless and that your MIG welding machine is correctly set up before you can embark on the welding process. 

  • It is recommended that you always have a Teflon wire liner fitted as this will help ensure good wire feed and help prevent contamination of the wire. Although stainless steel is a highly corrosion-resistant material, it is susceptible to contamination.Whenever you are welding a stainless steel using MIG, you need to know that any type of ferrous material present in the weld pool is capable of causing rust spots on the completed work.
  • You will have to ensure that the MIG torch is in excellent condition before you can start to weld. Like in welding aluminum, it will make lots of sense to purchase a larger torch than what you will use when welding ordinary steel.Since welding stainless steel emits more heat, the larger torch will always carry high amperages much better than the smaller torches.
  • Whenever you are working with stainless steel in MIG welding, it is crucial that you only use stainless steel wire brushes and cutting/grinding discs
  • When you consider the stainless steel vulnerability to ferrous contamination, you must ensure your working area is always free from steel or iron dust or any ferrous oxide. Although it can sound a bit trivial, it is of great importance.Material and workspace cleanliness is always important in ensuring suitable welding. When welding stainless steel using MIG welding, it is of great essence that you avoid even the smallest particulate contamination.
  • Before you can start welding, you need to ensure that the wire type and diameter are correct. Like in welding aluminum, it is also essential to ensure you clamp and tack your workpiece to avoid distortion and movement through cracking. 

Which Gas is Suitable for MIG Stainless Steel Welding?

I found many asking how to MIG weld stainless steel. One needs to choose the right type of gas when MIG welding. 

Some people go for pure argon or a blend of argon gas and other smaller gases to improve. Others opt for a specialist stainless gas mix like carbon dioxide, helium, and BOC’s Stain shield. 

When you are MIG welding stainless steel, you will always use a higher gas flow rate ranging from 14 LPM to 16 LPM. 

It is advisable that you first contact gas suppliers to help you know the gas requirements for the project you will be working on. 

TIG Welding

When TIG welding stainless steel, it is important to use DC only machine or consider using the AC/DC TIG welding machine when in DC mode. You will have to ensure that your machine has enough power to weld the stainless steel. 

  • In case you are not sure about your machine’s capability or if you are in the market for a stainless steel welding machine, ensure you always consult with the machine supplier for advice on the right type of machine and settings. 
  • When TIG welding stainless steel, it is vital that you know cleanliness is essential. Ensure that you clean the materials and workspace thoroughly.Like in MIG welding stainless steel, you will always use a stainless steel brush when TIG welding stainless steel when it is dirty.  When oily, degrease always.
  • Ensure that you have your torch set up for TIG stainless steel welding. Have the torched checked if it has the right duty cycle for the amperage being run? Remember never to cut on the corners. In case the torch is not up to the task, get one that is. 
  • Never overlook the essential torch consumables. Always pay attention to having the eight gas cups, choosing the tungsten type correctly, and getting the electrode’s diameter right. 
  • Always use a slightly larger gas cup diameter than the ordinary ones. Fit the gas lens to help in boosting the gas flow over the weld. Ensure that you keep it cool and offer some extra shielding for the weld pool. 
  • It is also vital that you ensure you go for the right rod, considering the stainless steel grade you will be welding. 
  • The rod thickness needs to be right. Thin stainless steel will require thinner rods to help in delivering the right deposition rates. However, this depends on the type of job you will be doing, and it is recommended that you always seek advice from your rod or TIG filler manufacturer. 
  • Whenever you discuss the filler rods, ensure that you wipe the filler rod clean to help remove any oil residue. 
  • To ensure optimum control and precision, always use a TIG torch and TIG foot pedal together with a variable amperage control. 
  • When welding thinner stainless steel, always consider pulse welding. Welding the plate face can be quite different from welding places such as the same piece’s edge.Whenever you are TIG welding the stainless steel, pulse welding will always reduce distortion as it will reduce the heat that goes into the weld. In case this is a consideration, you have to ensure that the machine you use for TIG welding has a pulse welding capability.

MMA Welding

Give special attention if you are wondering how do you weld stainless steel using MMA welding? MMA welding is considered the most straightforward process compared to MIG and TIG welding of stainless steel. 

Apart from being the simplest in setting up and using, it is also the cheapest for welding stainless alloys. 

When you have a welding machine with a stick welding capability, all you will require to start welding is just the right type of rods. You will not require any torch, gas, torch consumables, or foot pedals. 

  • The stainless steel will always move the welding tables. Hence, you need to ensure that you tack or clamp welds it to the workpiece. 
  • Ensure that you select the right electrode for the work. The most typical ones are sizes 316,308 or 312
  • Keep in mind that you will not be in a position of welding thin stainless steel sheets. Most of the welders usually struggle with stainless steel those measures less than 2mm in thickness. It narrows down to the MMA arc welding controllability for such types of applications. 
  • The thin sheet might be quite challenging to use. However, compared to mild welding steel to stainless steel or high-carbon tools, the steel will always play to the MMA strengths. 

Conclusion

We hope you now know how to weld stainless steel using MIG, TIG, and MMA welding.  To ensure your safety whenever you are welding always use safety gadgets. The safety gadgets will help protect your face and eyes from the flames or lighting. 

In case you are not sure about the type of welding to use, always feel free to consult a professional.  It is also important that you consider learning how to stick weld stainless steel as it will help make your work of welding stainless steel easy and fast. 

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