If you really want a coating of Inconel 718, there is only one way: build-up welding. There are different welding methods for this, each with its advantages and disadvantages. In theory, you can also apply Inconel 718 by means of thermal spraying, but the quality of this coating is poor compared to build-up welding.

But immediately the counter question: why of all things Inconel 718? An inner coating of the pipe must be corrosion-resistant and no more. Inconel 718 is corrosion resistant, but that is not its main property, which is its high temperature strength. Nickel superalloy Inconel 718 was developed for high mechanical loads at temperatures of up to approx. 900°C and is used in gas turbines and not in the corrosion protection of pipes.

There are other nickel-based alloys that have been specially developed for coatings and corrosion protection. First and foremost, these are materials from the NiCrBSi system, which can be applied to the steel surface using build-up welding or flame spraying with subsequent sintering. Since NiCrBSi alloys have a flux effect and a relatively low melting point, they are much better suited for application to steel than Inconel 718. In addition, these alloys are more corrosion-resistant, more wear-resistant and much cheaper.

Thanks so much dear Vadim Verlotski. I am trying to find the best Inconel and possible coating system. I appreciate your kindness and I hope you share more with me. Vadim Verlotski

Dear Mohammed,

I recommend you to study the literature on NiCrBSi alloys. This is an old and valued system with a lot of information and experience. Also visit this forum:

https://www.gordonengland.co.uk/sef/

Dear Vadim,

Thanks so much for your recommendation. I am trying to use this website (https://www.gordonengland.co.uk/sef/) but no option to share my questions. I do not know why Vadim Verlotski