Before Bonding Ceramic Liners: What Should You Check on the Steel Surface?

Before Bonding Ceramic Liners: What Should You Check on the Steel Surface?

A steel surface may look clean after blasting. Before ceramic tiles are bonded inside a pipe spool or onto a chute panel, what should an inspector actually check?

Start with four items: visual cleanliness, surface profile, contamination, and the specified bonding procedure. The purchaser needs evidence that the prepared surface and installation process meet the selected adhesive system's requirements.

Understand what the cleanliness grade confirms

Inspection reports may specify Sa 2½, a very thorough blast-cleaning grade under ISO 8501-1. It describes the visual cleanliness of the steel surface after blast cleaning. It does not, by itself, specify the required surface profile or verify the strength of a ceramic-to-steel bond. [1]

ISO 8503-1 separately addresses surface profile comparators for abrasive blast-cleaned steel. A useful inspection record therefore distinguishes the cleanliness grade from the profile requirement and its assessment method. [2]

The following checks are engineering recommendations for preparing that record, rather than a universal ceramic installation specification.

Agree the requirements before blasting

For bonded ceramic tile lined pipe or chute panels, request a written installation procedure that identifies:

• The steel preparation grade, required profile and assessment method.
• How oil, dust, moisture and relevant soluble contamination will be checked.
• The adhesive identity, mixing instructions, application limits and cure requirements.
• Any preparation required on the ceramic bonding face.

Record the applicable document revision. A material substitution should trigger a procedure review before installation continues.

Avoid copying a profile value from an unrelated lining product. For example, Henkel's LOCTITE PC 7218 data sheet describes a ceramic-filled epoxy wearing compound and gives its own preparation and cure instructions. It does not qualify an adhesive for bonding separate ceramic tiles. [3]

Make the inspection traceable to the component

Agree on a hold point before covering the prepared steel. Record the component identification, inspection time, photographs, preparation results and environmental checks required by the approved procedure.

For an existing chute, include repaired areas and surfaces beside welds or corners in the inspection plan. For a pipe spool, identify how the internal surface will be inspected and documented. A photograph of an easily accessible area may leave the hardest-to-reach area unverified.

Where acceptance depends on a measurement, record the method and result. A general photograph is supporting evidence rather than a substitute for that measurement.

Record the cure before releasing the lining

The release record should identify adhesive batches, mixing records, installation times and the temperature conditions relevant to the specified cure.

If the procedure bases curing on substrate temperature, ambient air temperature alone is insufficient. A surface that feels dry also does not establish that the specified cure has been achieved.

Include deviations, repairs and the person responsible for accepting them. This gives maintenance staff something useful to review if tiles later detach.

What should a purchaser request?

Ask for a component-specific preparation and installation record alongside the ceramic material certificate.

If a lining fails, preserve the exposed steel, adhesive and ceramic fracture surfaces where practicable. Compare them with the installation record and operating history before assigning a cause.

A useful acceptance record shows how the steel was prepared, how the tiles were bonded and whether the specified curing conditions were met. This makes the installation easier to review before commissioning and more traceable during later maintenance.

Technical References

[1] International Organization for Standardization. Preparation of steel substrates before application of paints and related products — Visual assessment of surface cleanliness — Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings. ISO 8501-1:2007. 2007.

[2] International Organization for Standardization. Preparation of steel substrates before application of paints and related products — Surface roughness characteristics of blast-cleaned steel substrates — Part 1: Specifications and definitions for ISO surface profile comparators for the assessment of abrasive blast-cleaned surfaces. ISO 8503-1:2012. 2012.

[3] Henkel. Technical Data Sheet: LOCTITE PC 7218. November 2019.