How do you calculate a corrosion resistance risk score?

Multiply the three ratings: severity x occurrence x detection. With severity 6, occurrence 4, and detection 3 you get a risk score in the low hundreds range, which you then compare against your other rated corrosion failure modes.

What is a good corrosion resistance score?

Lower is better. There is no universal pass line, but many plating shops set an action threshold around 100 (on a 1-10-1000 scale) and always investigate any mode where severity alone is 9 or 10 regardless of the product.

What do severity, occurrence, and detection mean for coatings?

Severity is how damaging red rust or coating loss would be to the end product, occurrence is how frequently the coating fails salt-spray or field exposure, and detection is how reliably your inspection catches a bad coating before it ships.

Corrosion resistance score vs salt-spray hours: what's the difference?

Salt-spray hours measure a coating's raw performance in a test chamber, while the resistance score is a risk-ranking tool. A coating can pass salt spray yet still earn a high risk score if the process is unstable and detection is weak.

How do I lower a high corrosion risk score?

Attack the biggest multiplier. If detection is a 3, adding automated coating-thickness gauging drops that number; if occurrence is high, tighten bath chemistry or chromate dwell time. Severity is usually fixed by the design.

Should I re-score after a corrective action?

Yes. Re-rate occurrence and detection after the fix is validated and recompute. A meaningful FMEA shows the score falling below your action threshold once controls are proven.

Plating, Anodizing & Surface Treatment calculator

Corrosion Resistance Score Calculator

The Corrosion Resistance Score is an FMEA-style Risk Priority Number applied to coating and plating failures. It multiplies how bad a corrosion failure would be (severity), how likely it is to happen (occurrence), and how likely your salt-spray, humidity, or visual checks are to catch it before shipment (detection). Plating engineers and quality teams use it to rank which corrosion risks — thin zinc, poor chromate passivation, missed edge coverage — deserve corrective action first. It turns a vague 'this part rusts sometimes' into a comparable number you can trend and act on.

What this calculator does

Estimate corrosion resistance for plating, anodizing and surface treatment using production-ready inputs so teams can rank risks and decide which issue needs containment, controls, or escalation first.
Use it when corrosion resistance in plating, anodizing and surface treatment needs a defensible ranking against other plating, anodizing and surface treatment risks for the next review.
It computes an RPN-style risk score by multiplying the severity, occurrence, and detection ratings for a specific corrosion failure mode.

Formula used

Corrosion resistance risk score = corrosion resistance severity score × corrosion resistance occurrence score × corrosion resistance detection score
Use the same scoring scale across comparable corrosion resistance risks.

Inputs explained

Corrosion severity (impact of a coating failure):
Corrosion occurrence (how often the defect appears):
Corrosion detection (odds inspection catches it):

How to use the result

Use it during coating FMEAs, PPAP reviews, or after field corrosion complaints to prioritize which failure modes to fix first.
The score is only meaningful when everyone rates on the same 1-10 scale; a high number flags priority but does not tell you the root cause or the fix.

Current U.S. benchmarks

The producer price index for industrial chemicals stands at 344.336 (BLS, May 2026), up 16.1% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 14,543 chemical manufacturing establishments employing about 911,245 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate a corrosion resistance risk score? Multiply the three ratings: severity x occurrence x detection. With severity 6, occurrence 4, and detection 3 you get a risk score in the low hundreds range, which you then compare against your other rated corrosion failure modes.
What is a good corrosion resistance score? Lower is better. There is no universal pass line, but many plating shops set an action threshold around 100 (on a 1-10-1000 scale) and always investigate any mode where severity alone is 9 or 10 regardless of the product.
What do severity, occurrence, and detection mean for coatings? Severity is how damaging red rust or coating loss would be to the end product, occurrence is how frequently the coating fails salt-spray or field exposure, and detection is how reliably your inspection catches a bad coating before it ships.
Corrosion resistance score vs salt-spray hours: what's the difference? Salt-spray hours measure a coating's raw performance in a test chamber, while the resistance score is a risk-ranking tool. A coating can pass salt spray yet still earn a high risk score if the process is unstable and detection is weak.
How do I lower a high corrosion risk score? Attack the biggest multiplier. If detection is a 3, adding automated coating-thickness gauging drops that number; if occurrence is high, tighten bath chemistry or chromate dwell time. Severity is usually fixed by the design.

Last reviewed 2026-05-12.