Frequently Asked Questions about Thermal Spray Services

How do you measure thermal spray thickness?

Measuring thermal spray thickness depends on the substrate material and the thermal spray alloy. The thickness of non-ferrous alloys applied to a ferrous substrate can be directly measured using a magnetic lift-off (MLO) gauge. If the applied alloy is ferrous or the substrate is non-ferrous then the thickness can’t be measured and can only be controlled with a suitably engineered application process.

How do you stop pressure vessel corrosion?

You need to maintain the wall thickness which acts as your pressure boundary. You can do this by applying a protective barrier if the vessel is suffering from wall thickness loss or metal wastage caused by erosion, corrosion, or a combination of both.

How is thermal spray applied?

Thermal spray alloys are deposited onto the surface by melting a wire or powder (or a combination of both) feedstock in the spray gun and projecting them at high velocity onto a suitably prepared substrate where the droplets form splats and interlock with each other to form an impermeable barrier.

Is thermal spray hot work?

Thermal spray is hot work, however, for the substrate, it is a cold process. In other words, it does not induce or create thermal stress, e.g., heat affected zones (HAZ).

What corrosion mechanisms can thermal spray stop?

Thermal spray can stop or prevent a variety of corrosion mechanisms including pitting (H2S, CO2), hydrogen-induced cracking (HIC), stress corrosion cracking (SCC), and choline or sulfur-induced (H2SO4) corrosion, among others.

What is the difference between weld overlay and thermal spray?

Weld overlay is the application of metal using a welding process. Welding requires fusion of the metal substrate with the weld bead, a metallurgical bond that induces thermal stress, heat affected zones (HAZ) and requires pre- and post-weld heat treatment (PWHT).

Integrated Global Services (IGS) High Velocity Thermal Spray, HVTS Solution cladding is deposited using a high velocity process which creates a mechanical bond to the prepared substrate without inducing any thermal stress.

What materials can be thermal sprayed?

Most alloys can be applied using a thermal spray process, however, to create an impermeable corrosion barrier the correct process and alloy composition must be selected. Integrated Global Services (IGS) typically uses a proprietary High Velocity Thermal Spray, HVTS Solution process with a nickel-chrome-molybdenum-based alloy to stop erosion and corrosion in heat exchangers, boilers and process vessels.

What substrates can you apply thermal spray to?

Thermal spray can be applied to any substrate which can be suitably prepared.

What surface preparation is required for thermal spray?

Typical preparation requires abrasive blasting to generate the specified surface profile and cleanliness.

Why do process vessels corrode?

Process vessels corrode when the substrate is chemically attacked by the process environment. This can occur when there is a change of use or operating conditions, due to a poor design or the failure of the installed corrosion barrier.

Will thermal spray add mechanical strength to the vessel?

Thermal spray will freeze the condition and maintain the existing mechanical strength for the long term, but it will not add mechanical strength. For the application of thermal spray to be considered, the process vessel needs to pass a Fitness For Service (FFS) test.

Can you thermal spray stainless steel?

Yes, you can apply stainless steel using a thermal spray process and you can also apply a higher nobility alloy onto suitably prepared stainless steel.