Material Selection for Industrial Wedge Wire Screens
We manufacture from 10 grades — stainless, duplex, and carbon-alloy steels. The right grade depends on chemistry, temperature, abrasion, and regulatory requirements. Material certificates per EN 10204 Type 3.1 supplied with every order.
Stainless Steel Grade Comparison
Chromium provides corrosion resistance. Nickel adds toughness and formability. Molybdenum improves resistance to chloride pitting. The right combination depends on your process chemistry, temperature, and mechanical loads.
| Grade | Cr % | Ni % | Mo % | Advantage | Corrosion Rating |
|---|---|---|---|---|---|
| SS 304 | 18.0–20.0 | 8.0–10.5 | — | Cost-effective, general industrial use | Good |
| SS 304L | 18.0–20.0 | 8.0–12.0 | — | Low carbon, superior weldability | Good |
| SS 316 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | Chloride and chemical resistance | Very Good |
| SS 316L | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | Low carbon 316, food and pharma grade | Very Good |
| SS 316Ti | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | Titanium stabilized, high-temp service | Very Good |
| SS 321 | 17.0–19.0 | 9.0–12.0 | — | Oxidation resistant at sustained heat | Good |
| Super Duplex | 24.0–26.0 | 6.0–8.0 | 3.0–5.0 | 2x yield strength of 316L, seawater rated | Excellent |
Carbon and Alloy Grades for High-Workload Applications
When the operating environment is dry, controlled, or dominated by abrasion rather than corrosion, structural and wear-resistant steels deliver more performance per unit cost than stainless. Surface protection (coating, painting, or galvanizing) is required wherever moisture is present.
Carbon and alloy steels apply to drilled / perforated screen formats and structural support components — they are not used for V-wire profile screens, which are stainless only.
| Grade | Yield | Hardness | Best For | Avoid |
|---|---|---|---|---|
| S355 | 355 MPa | — | Indoor industrial screens, structural frames, dry aggregate handling, coated outdoor service | Wet or chloride exposure without coating; food-contact or hygienic applications |
| S700 | 700 MPa | — | Vibrating screen decks, heavy-load structural members, weight-sensitive designs | Welding without preheat protocol; corrosive or wet environments without coating |
| Hardox 400/450/500 | 1000–1300 MPa | 370–530 HBW | Mining, sand and gravel, coal handling — applications where abrasive wear is the dominant failure mode | Tight forming or bending; sustained service above ~250 °C; corrosion-driven environments |
Carbon and alloy steels have no inherent corrosion resistance. They require coatings, controlled environments, or scheduled replacement. Hardox is SSAB-proprietary; specify the exact hardness class (400 / 450 / 500) on order.
Material Choices by Industry
Each industry creates a typical environment profile — chloride exposure, temperature range, abrasion level, and regulatory standards. These are the grades we deliver most often per sector. Use them as a starting point, not a final decision.
Water & Wastewater
Cost-driven for municipal freshwater. Switch to 316L when chloride from disinfection or source water exceeds ~200 ppm.
Food & Beverage
316L meets FDA, 3-A, and EHEDG requirements for CIP cleaning chemistry. Electropolish to Ra < 0.8 μm for hygienic surfaces.
Mining & Minerals
Choose by dominant failure mode: abrasion → Hardox; structural load → S700; combined corrosion and abrasion → Duplex 2205.
Oil & Gas
H₂S service requires NACE MR0175-qualified materials. Offshore intakes need PREN > 40 for sustained seawater exposure.
Chemical Processing
Match to pH, chloride concentration, and operating temperature. Above 400 °C, titanium-stabilized austenitics resist sensitization.
Power Generation
Cooling water selection follows the source — fresh, brackish, or seawater. Flue gas desulfurization needs high-temperature grades.
Pulp & Paper
Bleach plants and black liquor service combine chlorides with oxidizers — duplex grades resist both. Mild fiber recovery streams allow 316L.
General Industrial
Cost-driven for indoor and dry environments. Coastal or chlorinated air pushes selection to 316L; heavy mechanical load to S700.
Marine & Aquaculture
Fish farms, marine intakes, and offshore platforms run continuously in chloride-rich water. PREN > 40 is the practical threshold for 25-year service life.
Four Questions That Narrow the Choice
Most material decisions come down to four parameters. Answer them in order — the field of candidates shrinks fast and what's left is usually one or two grades.
How much chloride?
Chlorides drive pitting in 300-series stainless. Approximate thresholds: 200 ppm for 304-class, 1,000 ppm for 316-class, 3,600 ppm for Duplex 2205, full seawater for Super Duplex 2507.
< 200 ppm → 304L · 200–1,000 ppm → 316L · brackish → Duplex 2205 · seawater → Super Duplex 2507
What is the operating temperature?
Above 400 °C, carbide precipitation becomes a concern in standard austenitics. Above 300 °C, duplex grades risk 475 °C embrittlement and lose their strength advantage.
< 400 °C → 304L / 316L · > 400 °C with chloride → 316Ti · > 400 °C without chloride → 321
How abrasive is the feed?
Slurry, sand, and aggregate wear screens by mechanical attrition. Surface hardness — not corrosion rating — drives selection here. Wear-resistant steels can deliver 3–4× the service life.
Low → standard SS · Moderate + chloride → Duplex 2205 · Extreme → Hardox 400 / 450 / 500
Are there hygienic or regulatory requirements?
Food, dairy, beverage, and pharmaceutical processes require surfaces that withstand CIP/SIP chemistry and meet FDA, 3-A, or EHEDG criteria. Sour-service oil & gas requires NACE MR0175 qualification.
Food / pharma → SS 316L electropolished · Sour service (H₂S) → Duplex 2205 per NACE MR0175
Not sure which grade fits your application?
Use our Material Selection Wizard for a guided recommendation based on your operating chemistry, temperature, and abrasion profile — or jump to the Quality page for inspection standards and documentation.