Diamond Brite Metals — Pit Free Finish Standards

Customer Responsibility

It is the customer’s responsibility to specify whether a flat-rolled product must be “Pit Free” after polishing.

Pit Free standards require specialized polishing processes and more stringent inspection criteria than standard grit or industry finishes.

Diamond Brite Metals recommends that customers specify a maximum Roughness Average (RA) requirement when ordering a Pit Free finish.

1. Standard Industry or Grit Finishes

A standard industry finish (e.g., #4, #6) or grit finish (e.g., 180 grit, 220 grit) is achieved by mechanically polishing flat-rolled products using abrasive belts. These belts produce a uniform, directional appearance.

• Measurement: These finishes are not measurable with a profilometer and cannot be converted to RA/RZ/RMS values.

• Pitting & Surface Imperfections: Surface imperfections and pitting are allowed.

2. RA/RZ/RMS Finishes

An RA/RZ/RMS finish is a measurable finish that visually resembles the corresponding industry or grit finish but can be verified and certified using a profilometer. These finishes are commonly required for sanitary or high-specification applications.

• Measurement: Measurable with a profilometer and certifiable to a specified RA/RZ/RMS value.

• Pitting & Surface Imperfections: Pitting is allowed unless a Pit Free requirement is specified. Many end-use applications requiring an RA/RZ/RMS finish also require a Pit Free designation.

3. Pit Free #1 Finish

A measurable finish (RA/RZ/RMS) verified with a profilometer. Tooling ensures consistency, and a visual inspection confirms pitting tolerance.

• Pitting & Surface Imperfections:

  • Pits under 0.02" in diameter or length do not need to be removed (per ASME BPE-2015 Part SF).

  • Pits over 0.02" in diameter or length are allowed only if there are no more than two (2) pits per square foot of surface area.

4. Pit Free #2 Finish

A measurable finish (RA/RZ/RMS) verified with a profilometer. Tooling ensures consistency, and a visual inspection confirms pitting tolerance.

• Pitting & Surface Imperfections:

  • Pits under 0.02" do not need to be removed (per ASME BPE-2015 Part SF).

  • All other pits must be removed by hand tooling, which may leave a slight impression on the plate. The impression area must still meet the required RA/RZ/RMS value.

5. Pit Free #3 Finish

A measurable finish (RA/RZ/RMS) verified with a profilometer. Tooling ensures consistency, and a visual inspection confirms pitting tolerance.

• Pitting & Surface Imperfections:

  • Pits under 0.02" do not need to be removed (per ASME BPE-2015 Part SF).

  • All other pits must be removed by machine, leaving no visible impression.

Note

Diamond Brite Metals reserves the right to reject any material deemed unsuitable for polishing to the specified finish prior to processing.