AWS Class ER309/309L is a popular welding alloy in the austenitic stainless steel family. This metal is widely used in various industries where the corrosion-resistant properties of stainless steel are required in high-temperature environments. ER309/309L is suitable for MIG and TIG welding processes, making it a versatile alloy for different applications. This blog will delve deeper into the composition, physical, and mechanical properties of the AWS Class ER309/309L MIG and TIG, its applications, and heat treatment.
What is AWS Class ER309/309L MIG & TIG?
AWS Class ER309/309L MIG & TIG welding wire is the most widely used, multi-purpose stainless steel filler metal. It has a low carbon content that helps to provide good weldability and corrosion resistance, making it ideal for joining dissimilar alloys or surfacing austenitic stainless steel. It can be used for all positions of welding applications with either gas-shielded or open-arc techniques. This filler wire also provides excellent mechanical properties such as tensile strength, elongation, impact value and other toughness characteristics, which are suitable in various environments ranging from cryogenic temperatures up to 2100°F (1149°C).
ER309/309L MIG & TIG Welding Wire Composition
The AWS Class ER309/309L welding electrode comprises significant amounts of chromium, nickel, and iron, with little to no carbon content. The alloy also contains small amounts of silicon and manganese. The addition of 23-25% chromium and 12-14% nickel makes the alloy particularly resistant to scaling, oxidation, and corrosion. The low carbon content allows the alloy to maintain its austenite structure, even after exposure to high temperatures.
| C | Cr | Ni | Mo | Mn | Si | P | S | Cu |
| 0.03 | 23.0-25.0 | 12.0-14.0 | 0.75 | 1.0-2.5 | 0.30-0.65 | 0.03 | 0.03 | 0.75 |
ER309/309L MIG & TIG Coated Wire Physical Properties
The AWS Class ER309/309L MIG & TIG has excellent physical properties, making it a popular welding consumable. The alloy has a density of 7.93 g/cm3, a melting point of 1398-1420°C, and a thermal conductivity of 15.9 W/mK. The high melting point makes AWS Class ER309/309L suitable for high-temperature applications, such as furnace components, exhaust systems, and heat exchangers.
ER309/309L MIG & TIG Welding Wire Mechanical Properties
Regarding mechanical properties, AWS Class ER309/309L MIG & TIG has exceptional strength, flexibility, and toughness, making it ideal for welding dissimilar metals, including mild steel, stainless steel, and even cast iron. The alloy has a tensile strength of 650 MPa, yield strength of 410 MPa, and an elongation of 35%. The high toughness of AWS Class ER309/309L makes it resist cracking and failure under stress.
| Tensile Strength, kpsi: | 86* |
| Yield Strength, kpsi: | 58* |
| Elongation %: | 40* |
ER309/309L MIG & TIG Coated Wire Trade Name
| Class | UNS | Oxford Alloys | SANDVIK | BOHLER |
| ER309/309L | S30983 | Alloy 309/309L | EXATON 22.15.3.L | BOHLER THERMAINT 25/14 E-309L |
ER309/309L MIG & TIG Welding Wire Parameters
| Diameter | Process | Volt | Amps | Shielding Gas | |
| in | (mm) | ||||
| .035 | (0.9) | GMAW | 22-23 | 180-210 | Spray transfer 98% Argon/2% Oxygen |
| .045 | (1.2) | GMAW | 23-25 | 195-260 | Spray transfer 98% Argon/2% Oxygen |
| 1/16 | (1.6) | GMAW | 25-28 | 260-390 | Spray transfer 98% Argon/2% Oxygen |
| .035 | (0.9) | GMAW | 19-23 | 55-170 | Short Circuiting Transfer 90% Helium/ 7 ½% Argon / 2 ½% CO2 |
| .045 | (1.14) | GMAW | 19-23 | 100-185 | Short Circuiting Transfer 90% Helium/ 7 ½% Argon / 2 ½% CO2 |
| .035 | (0.9) | GTAW | 12-15 | 60-100 | 100% Argon |
| .045 | (1.14) | GTAW | 13-16 | 70-120 | 100% Argon |
| 1/16 | (1.6) | GTAW | 14-16 | 90-130 | 100% Argon |
| 3/32 | (2.4) | GTAW | 15-20 | 120-175 | 100% Argon |
| 1/8 | (3.2) | GTAW | 16-20 | 150-220 | 100% Argon |
ER309/309L MIG & TIG Coated Wire Uses
The AWS Class ER309/309L MIG & TIG coated electrode has diverse applications in various industries, including food processing, chemical processing, and petrochemicals. The alloy is commonly used to fabricate equipment, containers, piping, and fittings exposed to corrosive environments. AWS Class ER309/309L is also used for welding heat-resistant alloys such as Inconel and Hastelloy.
ER309/309L MIG & TIG Welding Wire Heat Treatment
AWS Class ER309/309L MIG & TIG can be heat-treated to improve mechanical properties. The metal can be annealed at 1040 to 1150 °C to restore its austenitic structure and improve its resilience after welding. The alloy can be quenched in water or oil to enhance its hardness. However, AWS Class ER309/309L is susceptible to carbide precipitation, which can reduce its corrosion resistance. Hence, post-weld heat treatment must be done with caution.
ER309/309L MIG & TIG Coated Wire Corrosion Resistance
The high level of chromium and nickel in AWS Class ER309/309L MIG & TIG makes it highly resistant to oxidation, scaling, and corrosion. The alloy is particularly suited to resist corrosion in high-temperature environments. Adding molybdenum can enhance the alloy’s resistance to pitting and crevice corrosion.
Conclusion
AWS Class ER309/309L MIG & TIG is a versatile alloy with excellent weldability, mechanical strength, and corrosion resistance. The alloy has various applications in various industries where resistance to scaling and corrosion is essential. The physical and mechanical properties of AWS Class ER309/309L make it ideal for welding dissimilar metals, including heat-resistant alloys such as Inconel and Hastelloy. With proper heat treatment, AWS Class ER309/309L MIG & TIG can improve its properties and enhance its resilience after welding. AWS Class ER309/309L MIG & TIG is an essential ingredient in welding alloys that delivers impressive results in high-temperature environments.
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