Difference Between Inconel 625 and Stainless Steel 316L

In the manufacturing industry, the selection of appropriate materials holds significant importance in assuring the quality and longevity of the end product. Two popular materials often compared and used in different industrial applications are Inconel 625 and stainless steel 316L. It can be difficult to determine which material best suits your application, so in this post, we will compare Inconel 625 and stainless steel 316L to help you make an informed decision.

Inconel 625 is a nickel-chromium alloy, the lowest chromium content version, with an addition of molybdenum work as an enhancer. The alloy’s chemical composition allows its high corrosion & oxidation resistance. Inconel 625 is commonly used in chemical handling & marine applications due to its exceptional resistance to pitting, crevice corrosion, erosion and intergranular corrosion. Able to resist to mineral acids such as nitric, phosphoric, sulfuric and hydrochloric acid. Good resistance to alkalis and organic acids.

Beside excellent corrosion resistance, Inconel 625 is non-magnetic and spark resistant. This set of physical properties is useful in applications such as downhole equipment and tooling for oil and gas exploration. Risers, tube hangers and high-strength fasteners all make use of Alloy 625’s properties. Natural gas processing equipment such as fluid separation units will also use Alloy 625, on account of its oxidation resistance and good thermal fatigue strength. As it is effectively austenitic in terms of microstructure, fabrication and processing is reasonably straightforward with the appropriate tooling and set-ups.

Stainless steel 316L is an austenitic stainless steel with low carbon content. The alloy’s chemical composition includes molybdenum, which increases corrosion resistance compared to other austenitic stainless steels. Stainless steel 316L is frequently used in food and pharmaceutical applications due to its high level of resistance to corrosion and oxidation.

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Inconel 625 is a nickel-based alloy, contains 20-23% chromium, 8-10% molybdenum, and 3-4% niobium, while stainless steel 316L is an austenitic alloy consisting of 16-18% chromium, 10-14% nickel, and 2-3% molybdenum. Inconel 625 has a higher nickel content, making it more resistant to corrosion and oxidation in extreme environments. Stainless steel 316L is less corrosion-resistant but can still be corroded in harsh environments.

Inconel 625 is known for high-temperature strength and excellent heat resistance. It can withstand temperatures above 2000°F without deforming or suffering any permanent damage. On the other hand, stainless steel 316L has a lower melting point and cannot withstand extreme temperatures effectively as Inconel 625.

Inconel 625 is a stronger and tougher material compared to stainless steel 316L. It has a higher yield and tensile strength, making it suitable for high-stress applications. Conversely, Stainless steel 316 is ductile and malleable for easily forming and shaping.

Inconel 625 and stainless steel 316L have unique advantages and disadvantages depending on the application. Inconel 625 is more expensive but ideal for applications requiring high-temperature resistance, excellent corrosion resistance, and strength, such as aircraft exhaust systems, gas turbines, and chemical processing industries. On the other hand, stainless steel 316L is more affordable and suitable for general applications, such as marine applications, pharmaceutical equipment, and food processing systems.

Stainless steel 316L is known for its excellent weld ability properties, making it ideal for welding applications. On the opposite, Inconel 625 is difficult to weld and requires specialized techniques to ensure proper welding.

In terms of availability, stainless steel 316L is more widely available than Inconel 625. This is primarily attributed to the lower cost of stainless steel 316L. Moreover, stainless steel 316L finds more widespread usage across various industries, contributing to the ease of sourcing suppliers.

In conclusion, Inconel 625 and stainless steel 316L have unique properties and applications. When deciding on the material for your specific application, factors such as environmental conditions, temperature requirements, strength, and budget should all be taken into account. Inconel 625 is an excellent choice for high-temperature and corrosive environments, whereas stainless steel 316L is well-suited for more general applications. It’s advisable to consult experts experienced in material selection to guarantee  the quality and reliability of your final product.

OSS Dai Duong contact details:

• Hotline: 1800 6968
• Fanpage: Dai Duong Stainless Steel

Editorial board: O S S Dai Duong