Chemical & Hazardous Applications
Pump Materials & Chemical Compatibility Guide | Avoid Corrosion & Leaks
One Wrong Material Choice Can Destroy a Pump
A pump can be perfectly sized for flow and pressure—and still fail early if the materials are wrong.
If you’ve experienced:
- Corrosion
- Seal swelling or cracking
- Rapid wear
- Pitting and rust
- Unexpected leaks
the issue may not be the pump brand or the motor… it may simply be material compatibility.
This guide explains pump materials in a practical way so you can avoid expensive mistakes.
What “Compatibility” Actually Means
When selecting pump materials, you’re protecting against three main risks:
1) Corrosion (Chemical Attack)
The liquid reacts with the metal or elastomers, causing rust, pitting, or breakdown.
2) Erosion (High Velocity Wear)
Fast-moving liquid (especially with solids) wears surfaces down over time.
3) Abrasion (Solids Damage)
Particles grind away at impellers, casings, and seals.
Many failures are a combination of all three.
Common Pump Metals (Simple Breakdown)
Cast Iron
Best for: clean water and non-corrosive liquids
Avoid for: most chemicals, aggressive liquids, coastal environments
Cast iron is affordable but not chemical resistant.
Stainless Steel (Often 304 / 316)
Best for: many industrial liquids, mild chemicals, food-grade and clean process liquids
Watch out for: strong chlorides, some acids, aggressive chemicals at high temperature
Stainless is a common “safe” choice, but it’s not universal.
Duplex / Super Duplex Stainless
Best for: more aggressive environments, higher corrosion resistance than standard stainless
Often used where chloride stress corrosion is a risk.
High-Alloy Materials (e.g., Hastelloy-type alloys)
Best for: strong acids and aggressive chemical environments
Usually used when standard stainless won’t survive.
These materials are typically higher cost but necessary in harsh service.
Non-Metallic Materials (Often the Best for Chemicals)
PTFE (Teflon) / Lined Pumps
Best for: corrosive chemicals where metals struggle
PTFE-lined components can offer excellent chemical resistance.
Watch out for:
- Temperature limits
- Mechanical damage from solids
- Installation and handling (lining can be damaged if misused)
Plastics (Depending on design)
Some pumps use engineered plastics for chemical resistance. These can be excellent in the correct application, especially for dosing and transfer.
Don’t Forget Elastomers (They Cause Many “Mystery Failures”)
Even if the pump body material is correct, the seals and O-rings might not be.
Elastomer selection matters for:
- Swelling
- Cracking
- Softening
- Chemical breakdown
Common elastomer types include:
- EPDM
- NBR
- Viton/FKM
The “wrong” elastomer can fail fast—even if everything else is correct.
Temperature Changes Everything
A chemical that is “fine” at ambient temperature can become aggressive at higher temperatures.
If your process runs hot (or has cleaning cycles), you must specify:
- Normal operating temperature
- Maximum temperature
- Any temperature spikes
Solids Content: The Compatibility Most People Ignore
Even small amounts of solids can destroy seals and impellers over time.
If your liquid contains:
- Sand
- Sludge
- Fibres
- Crystals
- Abrasive powders
you may need:
- Different pump type (not only different material)
- Slower speed operation
- Different impeller design
- Better filtration or straining
Real-World Examples of Common Problems
“We used stainless but it still corroded.”
Possible cause: chlorides, temperature, concentration changes.
“The seal keeps leaking.”
Possible cause: elastomer incompatibility, dry running, solids damage, vibration.
“The pump works but performance dropped quickly.”
Possible cause: erosion/abrasion wearing impeller and casing clearances.
What Information to Provide for Correct Material Selection
To select materials properly, ASW Engineering typically needs:
- Chemical/liquid name
- Concentration (important)
- Temperature range
- Any solids content (and type)
- Required flow and pressure/head
- Any cleaning chemicals used (CIP fluids, solvents, etc.)
If you don’t have everything, we can still help—just share what you know.
Need Help Selecting the Right Pump Materials?
Material compatibility is one of the biggest reasons pumps fail early—especially in chemical and industrial environments.
ASW Engineering supplies industrial pumps across South Africa and multiple regions in Africa, and we can recommend the correct materials and pump technology for your application.
If you want, send us your liquid details and duty point and we’ll guide you to a reliable, long-term solution.
Disclaimer: This article is provided for general informational purposes only and does not replace professional engineering advice or manufacturer documentation. Always verify suitability for your specific application and follow site safety procedures. ASW Engineering can assist with pump selection and technical support.