Key Feature

The Premium Ferritic Pipe with 316L-Level Corrosion Resistance. Molybdenum-enhanced, dual-stabilized ferritic stainless offering superior chloride resistance at lower cost than austenitic alternatives.

The highest corrosion-resistant standard ferritic grade pipe, often substituting for 316L in specific applications.

Common Designations

UNS S44400
EN 1.4521, X2CrMoTi18-2
JIS SUS444M
AISI 444 (Less Common)

Modern 444 has specific chemistry requirements different from older 18-2 grades.

Chemical Composition (Typical wt.%)

C: ≤ 0.025
Cr: 17.5 - 19.5
Mo: 1.75 - 2.50Ti: 0.20 - 0.80Nb: 0.10 - 0.50Ni: ≤ 1.00
N: ≤ 0.035

Dual stabilization (Ti+Nb) and molybdenum are critical for corrosion resistance and weld stability.

Mechanical Properties

Tensile Strength: ≥ 415 MPa
Yield Strength: ≥ 275 MPa
Elongation: ≥ 20%
Hardness: ≤ 217 HB

Similar strength to 430 but with significantly better corrosion resistance.

Physical Properties

Density: 7.75 g/cm³
Melting Range: 1425 - 1510 °C
Thermal Expansion: 10.4 × 10⁻⁶/K (20-100°C)
Thermal Conductivity: 25 W/m·K
Strongly magnetic

Low thermal expansion minimizes thermal stress in heat exchangers and thermal cycling applications.

Pressure Ratings

Schedule 10S/40S: Standard process piping
ASME B31.3 compliance
Comparable to 316L for many applications

Suitable for pressure applications; consult manufacturer for specific ratings.

Heat Treatment

Not hardenable by heat treatmentAnnealing: 800-900°C, rapid cool
Stress Relief: 650-760°C
Maximum Service Temperature: 400°C

Rapid cooling through 475-900°C range avoids embrittlement.

Corrosion Resistance

Excellent: Superior to 304, approaching 316L in chloride environments. Outstanding resistance to: stress corrosion cracking, pitting, crevice corrosion.

Specifically designed for chloride-containing waters and aggressive environments.

Welding Characteristics

Good weldability with proper techniques
Dual stabilization maintains properties
No post-weld heat treatment required
Matching filler metals recommended

Better weldability than standard ferritic grades due to stabilization.

Key Standards

ASTM A268 TP444: Seamless Ferritic Pipe
ASTM A789/A790: General Service Pipe
EN 10216-5: Seamless Pressure Tubes
JIS G3463: Stainless Steel Pipe
DIN 17457

Widely specified in Japanese JIS standards for water equipment applications.

Common Applications

• Heat Exchangers: Condenser tubes, plate heat exchanger piping
• Water Heating Systems: Hot water tanks, solar heater piping, heat pump systems
• Water Treatment: Chlorinated water piping, desalination plants, filtration systems
• Architectural: Coastal building services, pool fittings, marine fixtures
• Food Processing: Equipment exposed to chlorinated washdowns, brine lines
• Automotive: Exhaust system components (cold end), fuel lines
• Industrial: Chemical tanks (specific media), pollution control equipment

Ideal where chloride SCC resistance and moderate temperature stability are required.