Filler metal comes in a range of types, and 309 are the most popular among welders to make the weld strong, ductile, and rust-resistant.
Though you can apply MIG and TIG welding, or the Stick & Flux-cored welding process to weld stainless to stainless, you must be careful about applying filler metal. So can you use 309 to weld stainless to stainless?
Following that, we have discussed the possibility of welding stainless to stainless using a 309 filler rod and its related considerations.
Can You Use 309 To Weld Stainless To Stainless?
309 filler metal has a high amount of nickel and chromium, making it most appropriate for welding stainless to stainless. Yet, the 309 Tig Rod is designed to weld carbon steel to stainless steel. But by using this 309 to weld stainless to stainless, you will have a sturdy, ductile weld that will hold up to cooling cycles and heating.
Why should you use a 309 filler rod to weld stainless to stainless?
309 stainless steel has a higher proportion of nickel and chromium than other types, including 304. during welding stainless steel and carbon steel using this rod, some carbon steel mixes into the metal that is welding.
And it’s called dilution or admixture. Thus, the weld deposit still contains good amounts of nickel and chromium to make the weld strong, ductile, and crack resistant.
The weld will also hold up to cooling and heating cycles, making the weld corrosion resistant. Yet, you shouldn’t use a 309 stainless steel tig rod to weld pipes or tubes under high pressure.
The following are a few Hastelloy filler metals that aren’t suitable for welding carbon steel. Many DIYers consider nickel alloy rods a good option for welding high-strength steel to carbon steel, and they expect it won’t crack.
And if you use Hastelloy W, it can put you in a different situation where Hastelloy X would be the right choice. Feeling confused? Why the situation will change when both are pretty same Hastelloy rods, right?
One different number or the latter can bring different results, especially when you are talking about welding. There are lots of differences between Hastelloy W and Hastelloy X. Similarly, 309 and 309L can confuse you.
So, can you use 309L to weld stainless to stainless?
Firstly let’s begin with what the L means on the filler rods for stainless steel. The “L” type electrodes are preferred as the extra-low carbon type, in short, “ELC”.
Filler rods with lower carbon content means it will help reduce the harmful effects on the rust resistance of the heat-affected zone. That can be caused by the precipitation of intergranular carbide.
Now, what’s the difference between 309 and 309L filler rods? Though both ER 309L and ER 309 have quite the same composition, the first one has lower carbon content.
Thus, DIYers prefer ER 309L over 309 for welding low alloy steels or carbon. Even the 309L is also more suitable for dissimilar joints that endure heat treatment.
For example, you can use 309L or ER309LSi to weld low alloy steel or mild steel to stainless steel. Even if you need to weld 409 stainless steel to 409 stainless steel or to 304L stainless steel, you can still use a 309L filler rod. Another strong working zone for 309L filler rod is welding types 309 and 309 stainless steel.
Last but not least, you can use a 309L filler rod to weld type 304 stainless steel to type 304 stainless steel where it will undergo harsh rust conditions.
You can choose between 309 or 312 SMAW electrodes for welding stainless steel. Especially, if it projects is repair or maintenance. These filler rods will deliver good strength and high cracking resistance. More only, you can use these filler rods to weld the stainless steel that is already serviced.
The 309 Tig Rods is designed to weld stainless steel to carbon and leave a strong, ductile weld. It can also withstand cooling and heating cycles.
309 stainless steel welding alloys are suitable for welding base metals that are the same in cast form or shape composition.
You can also use 309 wires to weld type 304 stainless steel and other same base materials where harsh conditions may exist. Some welders also use these 309 wires to weld different steels.
So you can use 309 to weld stainless to stainless. You can even use this filer rod to weld carbon steel to stainless steel and different grades of SS.
But, it is preferable to use 309L over 309 for stainless steel itself as well as for dissimilar materials. For its low carbon steel content, 309L makes the welded area stronger, more corrosion resistant, and ductile.