Stainless steel resists corrosion at room temperature, but furnace heat changes the picture. In hot, oxidizing air, even stainless grows scale, pits and slowly loses section. A high temperature coating to prevent stainless steel oxidation adds a sealed barrier on top of the metal’s own protection.
Q: Why Does Stainless Steel Need a Coating at High Temperature?
A: Because Its Natural Oxide Layer Alone Is Not Always Enough in Sustained Heat
Stainless steel protects itself with a thin, chromium-rich oxide film. In ordinary service that film is enough. In hot, oxidizing atmospheres, and especially with corrosive gases, thermal cycling or chemical splash, the protection can be outpaced. Then the surface scales, pits and roughens over repeated heat cycles.
Glass-based coatings are one recognized way to shield steel at high temperature: a continuous glass layer slows oxygen and corrosive species on their way to the metal. Incure’s Epo-Weld™ HTSG-791 works on this principle. It is a single-part silicone-glass coating with a silicone binder filled with glass frit. During its heat cure the frit fuses into a continuous inorganic glass film.
Incure rates HTSG-791 for continuous service up to 1,400°F and describes the silicone-glass layer as supplementing the native oxide passivation layer on stainless steel. It does not replace that layer.
What HTSG-791 Brings to Stainless Components
- Oxidation and scaling protection for fixtures, brackets and structural parts in high-temperature oxidizing atmospheres.
- Chemical resistance after full cure to humidity, acids, alkalis and salt spray, per Incure’s catalog.
- A hard, inorganic finish at Shore D70 that does not carbonize the way organic paints do on first heating.
- Adhesion through the cure itself: Incure states the system bonds mechanically and chemically to metal oxide surfaces during the initial heat cure.
Beyond stainless steel, Incure lists adhesion to carbon steel, cast iron, ceramics and porous refractories. One product can therefore cover mixed assemblies such as a stainless bracket bolted to a cast-iron housing.
Email Us with your stainless grade, operating temperature and atmosphere to confirm whether HTSG-791 fits your components.
Applying HTSG-791 to Stainless Steel
The coating’s performance depends on a clean start and a complete cure.
- Clean and dry the surface. Remove oil, cutting fluids, fingerprints and loose oxide. Incure specifies application to a clean, dry substrate.
- Brush or spray. HTSG-791’s 400–800 cps viscosity gives a workable consistency for brushing complex shapes, and it can also be sprayed.
- Build thickness in coats. Incure notes that multiple coats can be applied to increase film thickness and coating density. Thin, even coats are less likely to crack than one heavy layer.
- Heat cure. Cure at 400°F for 1 hour. This step fuses the glass frit into a continuous film. There is no room-temperature cure option.
- First service heat-up. Incure notes the coating reaches full oxidation resistance and adhesion on its first excursion to service temperature.
Where Coated Stainless Parts Benefit
- Furnace fixtures, trays and brackets that cycle in and out of oxidizing heat.
- Structural supports near burners, flues and hot gas paths.
- Radiant tubes and manifold assemblies where scale buildup affects fit and heat transfer.
- Heat exchanger tube bundles and headers in high-temperature gas streams.
Parts that see welding heat tint, machining damage or frequent handling deserve attention at inspection. Those are the places where scaling tends to begin.
Q: Can HTSG-791 Go Over Existing Scale?
A: Remove Loose Scale First; the Coating Needs Sound Material to Bond To
Incure describes the silicone-glass system as bonding mechanically and chemically to metal oxide surfaces during the heat cure. That bond is only as good as the layer underneath. Flaking scale, rust bloom and loose oxide will lift away and take the coating with them. Clean back to tightly adherent material, then degrease and dry before coating.
Keeping Coated Parts in Service
Inspect coated stainless parts at planned shutdowns. Look for chips from handling, bare patches at sharp edges and any discoloration that suggests oxidation is reaching the metal. Small defects can be touched up with the same coating, followed by the 1 hour at 400°F cure before the part returns to full temperature.
Track where damage repeats. Recurring wear in one spot usually points to a mechanical cause, such as rubbing, impact or loading, that no coating will fully solve on its own.
How It Differs From Other Incure High-Temperature Products
HTSG-791 is a protective coating, not a sealant or structural adhesive. For flexible joint sealing, Incure’s Epo-Weld™ high temperature silicone sealers are the better match. For the full technical background on how the glass-frit barrier forms, see Incure’s product overview of Epo-Weld™ HTSG high temperature silicone glass adhesive. Broader coating chemistry trade-offs are covered in ceramic vs silicone high-temperature coatings.
Final Thoughts
A high temperature coating to prevent stainless steel oxidation adds a fused glass barrier where the metal’s own oxide film needs help. Incure’s Epo-Weld™ HTSG-791 brushes or sprays on, cures in 1 hour at 400°F and protects stainless and other metals up to 1,400°F. Contact Our Team to qualify it for your parts.
Visit www.incurelab.com for more information.