ThePipingMart Blog Welding Electrodes Alloy 309LMo SAW & Flux Welding Wire – Composition, Properties, and Uses

Alloy 309LMo SAW & Flux Welding Wire – Composition, Properties, and Uses

Alloy 309LMo SAW & Flux

Alloy 309LMo SAW & Flux is a welding coated electrode used in submerged arc welding designed to offer exceptional welding quality and excellent resistance to corrosion and heat. It primarily comprises nickel, chromium, molybdenum, and low carbon levels, making it a reliable option for welding in harsh environments. In this article, we will delve deeper into understanding everything there is to know about Alloy 309LMo SAW & Flux, from its composition, physical, and mechanical properties to its uses, heat treatment, and corrosion resistance.

What is Alloy 309LMo SAW & Flux?

Alloy 309LMo SAW & Flux is an alloy with filler metals developed by welding experts for high-pressure applications. It comprises Nickel, Chromium, Manganese, Molybdenum, and Iron. This combination forms an austenitic structure which results in a material that offers superior corrosion resistance over standard 309 when exposed to highly acidic or heat-reactive environments. The weldability of the alloy welds is even better than most stainless steel alloys due to its low carbon content and allows for efficient bead control during welding operations. Furthermore, this material has higher tensile strength than traditional 308 materials and provides excellent fabrication characteristics while possessing outstanding fatigue strength throughout multiple temperature ranges – making it a perfect choice for more demanding duties.

Alloy 309LMo SAW & Flux Welding Wire Composition

Alloy 309LMo SAW & Flux is composed of a range of materials, including 23 to 25% nickel, 12 to 15% chromium, 2.5 to 3.5% molybdenum, 0.75% silicon, and low levels of carbon. The low carbon levels make IT suitable for welding alloys and stainless steels containing lower carbon ranges. At the same time, the nickel, chromium, and molybdenum enable it to withstand harsh corrosive environments where corrosion resistance is necessary.

C Mn Si Cr Ni S P Mo Cu
0.03 max 1.0-2.5 0.30-0.65 23-25 12-14 0.03 max 0.03 max 2-3 0.75 max

Alloy 309LMo SAW & Flux Coated Wire Physical Properties

Alloy 309LMo SAW & Flux has excellent physical properties suitable for welding, including higher tensile strength and elongation properties, an above-average resistance to corrosion and heat and excellent oxidation resistance. Additionally, it has a higher density than many other welding alloy materials, making it a suitable option for high-pressure and high-stress welding environments.

Alloy 309LMo SAW & Flux Welding Wire Mechanical Properties

Alloy 309LMo SAW & Flux is a high-quality welding electrode with exceptional mechanical properties such as high flexibility, toughness, and corrosion resistance. It also boasts high strength and low thermal expansion desirable for welding.

Tensile Strength 89,900
Yield Strength 63,800
Elongation (%) 42%

Alloy 309LMo SAW & Flux Coated Wire Trade Name

Class UNS
309LMo S30986

Alloy 309LMo SAW & Flux Welding Wire Parameters





SAW Flux








OXF 300






OXF 300

Alloy 309LMo SAW & Coated Wire Flux Uses

Generally, Alloy 309LMo SAW & Flux is used in welding and fabrication across multiple industries. Due to its exceptional corrosion resistance and robust mechanical properties, it is popularly used in welding low-carbon, low-alloy, and austenitic stainless steel. It is also reliable in welding high-temperature components, such as boiler tanks, heat exchangers, and reactors, that require heat and corrosion resistance.

Alloy 309LMo SAW & Flux Welding Wire Heat Treatment

Alloy 309LMo SAW & Flux filler wire can either be used as-welded or post-weld heat treated, depending on the requirements of the welded component. However, post-weld heat treatment is typically recommended, especially for material that has been welded, to relieve residual stress and enhance overall mechanical properties.

Alloy 309LMo SAW & Flux Coated Wire Corrosion Resistance

Alloy 309LMo SAW & Flux’s primary strength lies in its ability to resist corrosion and oxidization due to its nickel, chromium and molybdenum content. It offers superior resistance to general corrosion, pitting, crevice corrosion, and stress corrosion cracking in chloride environments. Moreover, it is a better alternative to standard 304 and 316 austenitic stainless steels for reducing acid and halide chloride corrosion.


In conclusion, Alloy 309LMo SAW & Flux offers a range of superior properties and benefits, including high mechanical strength, excellent heat and corrosion resistance, and exceptional weldability. It is, therefore, ideal for welding a wide range of materials and for use in high-temperature and corrosive environments. The formulation of its composition and mechanical properties make it a premium option for welding austenitic stainless steels, low carbon steels, and low alloy steels that require exceptional quality and resistance to heat and corrosion.

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