What are 309 Welding Rods Used For?

Written By: Liam Bryant

Reviewed By: Russell Egan

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When you’re welding steel, you need a bit more power than you do for welding other metals. Steel has a higher melting point and is more powerful than other metals. You need a welding rod that can withstand high pressure, temperature, and other factors and make it through the job. There are welding rods that are designed specifically for welding steel.

The 309L welding rods are welding rods that are designed specifically for welding steel. They further specialize in joining steels that are different from one another. 

WeldingCity 309L Stainless Steel Welding Rod
  • Filler metal ER309L rod for TIG welding
  • Exhibits high strength and good toughness over a wide range of temperatures
  • U.S. based welding and hardware supplier
  • Strong technical support

The 309L welding rods have a few properties that make them different from other steel welding rods, which only work when they are working with similar base metals. Here is your guide to understanding how these rods work.

Properties of 309L Welding Rods

Before we talk about the application of 309L welding rods, it’s helpful to understand what makes them different from other welding rods. Here is an overview of their most important properties.

309l welding rod


In stick welding, the polarity of the electrode is important because it has to be compatible with the welding machine for the current to flow properly. While most welding rods are versatile, some only work with certain types of polarity. If you hook up the wrong type of electrode to your welding machine, then the quality of the weld will be affected.

The 309L rods can work with alternating current (AC) or direct current reverse polarity (DCEN) electricity. The coating type conducts these types of electricity.

Tensile Strength

The 309L welding rods have a very powerful tensile strength. According to some manufacturers, the tensile strength of these rods goes up to 80,000 psi (pounds per square inch), or 570 N/mm2 (Newtons per square millimeter). 

Welding rods that work with steel have to have a very high tensile strength because steel is such a tough material to work with. These rods need to withstand a lot of pressure without cracking to put together tough steel.


It is hard to find definitive information, but most users report medium penetration with this welding rod. It is not so deep that it will ruin thin materials, but it still gives you a decent welding pool.

Other Welding Properties

One of the most important properties that sets a 309L welding rod apart from a 309 is its material composition. The 309L welding rods have a much lower carbon content. That means they are more corrosion-resistant. The 309L welding rods are also highly resistant to cracking, so you can securely use them in your welding project.

What Is a 309L Welding Rod Used For?

The 309L welding rods are mostly used for welding steel. Specifically, you can use them for welding together different types of steel.

The steel combinations a 309L welding rod can fuse together include:

  • Austenitic steel to ferric steel
  • Austenitic cladding to ferric steel
  • Stainless steel and carbon steel
  • Stainless steel and low-alloy steel
  • Carbon steel and low-alloy steel

The versatility of the 309L welding rod makes it very important in industrial applications. Every industry, from aeronautics to automotive, sometimes must weld together different materials. Having a welding rod on hand that works well with steels of different properties can eliminate any headaches down the line.

Why Can’t Other Welding Rods Weld Together Different Types of Steel?

If 309L welding rods can weld together two types of steel, why can’t every welding rod? After all, you’re welding a metal either way.

One of the main risks of welding together dissimilar metals is corrosion. If you’re not careful, the welding could corrode, undermining the security of the weld joint. Even if there is no corrosion, different metals don’t fuse together as well, failing to create a secure joint. Finally, different metals, even different types of steel, have different melting points, so you could melt one piece and not the other. 

The unique properties of 309L welding rods provide a solution to this problem. Since 309L welding rods are low in carbon and resistant to corrosion, they are the perfect tool for navigating this problem. Plus, since they have such a high tensile strength, they can work with very tough pieces of steel without damaging the more fragile piece you are trying to connect.

Types of Welding Suited for 309L Welding Rods

There are a few situations in which you can use 309L welding rods, including:

  1. Dissimilar welding
  2. Structural welding
  3. Under-layer welding

These are just a few examples where 309L welding rods work best, but they function in any situation where you have to weld steel.

Final Thoughts

Joining together different grades of steel is a necessary part of welding together underlayers and overlayers or just normal manufacturing. This task is normally difficult due to different metal properties and corrosion risks, but a 309L welding rod is the perfect tool.