ASTM A815 CR33
ASTM A815 CR33 Wrought Stainless Steel Pipe Fittings
ASTM A815 CR33 refers to cold-worked welded stainless steel pipe fittings produced from high-performance ferritic stainless steel, typically associated with UNS S44626. These fittings are engineered for demanding environments requiring superior corrosion resistance, exceptional chloride stress-corrosion cracking resistance, and excellent oxidation resistance at elevated temperatures.
Widely used in chemical processing, power generation, desalination, and refinery systems, ASTM A815 CR33 ensures dimensional accuracy, structural integrity, and long-term durability in aggressive service conditions.
Key Features
Excellent resistance to chloride-induced corrosion and SCC
High oxidation resistance at high temperatures
Superior creep and thermal fatigue strength
Enhanced pitting and crevice corrosion resistance
Low thermal expansion and improved thermal conductivity
Cold-worked class offering increased strength and durability
Suitable for high-temperature flue gas and marine applications
Specification
| Property | Details |
|---|---|
| Standard | ASTM A815 |
| Grade | CR33 |
| UNS Equivalent | UNS S44626 |
| Material Category | Ferritic Stainless Steel |
| Form | Wrought Pipe Fittings |
| Class | Cold-worked Welded Fittings |
| Sizes | ½” to 48” (DN15 to DN1200) |
| Schedule | SCH 10 to SCH 160 / XXS |
| Connection Types | Butt-Weld / Socket Weld / Threaded |
| Manufacturing Process | Welded & Cold Worked |
Equivalent Grade
| Standard | Grade |
|---|---|
| UNS | S44626 |
| ASTM | A815 CR33 |
| EN | Comparable to 1.4742 / (Ferritic Stainless Steel Class) |
| JIS | Comparable ferritic grade reference |
Note: CR33 is a special ferritic grade; exact EN/JIS equivalents may vary.
Available Sizes
Pipe Fittings Range: ½” – 48”
Wall Thickness: SCH 10 – XXS
Forms: Elbows, Tees, Reducers, Stub Ends, Caps, Crosses
Chemical Composition (% max/min)
| Element | Composition (%) |
|---|---|
| Chromium (Cr) | 26.0 – 29.0 |
| Molybdenum (Mo) | 2.0 – 4.0 |
| Nickel (Ni) | ≤ 1.0 |
| Carbon (C) | ≤ 0.02 |
| Manganese (Mn) | ≤ 1.0 |
| Silicon (Si) | ≤ 1.0 |
| Nitrogen (N) | ≤ 0.03 |
| Iron (Fe) | Balance |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | ≥ 485 MPa |
| Yield Strength | ≥ 345 MPa |
| Elongation | ≥ 20% |
| Hardness | ≤ 30 HRC |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.75 g/cm³ |
| Melting Point | ~1450°C |
| Thermal Conductivity | Higher than austenitic grades |
| Thermal Expansion | Lower than 300 series SS |
| Modulus of Elasticity | ~200 GPa |
Types of ASTM A815 CR33 Fittings
ASTM A815 CR33 Elbow
ASTM A815 CR33 Tee
ASTM A815 CR33 Reducers
ASTM A815 CR33 Caps
ASTM A815 CR33 Cross Fittings
ASTM A815 CR33 Nipples
ASTM A815 CR33 Couplings
ASTM A815 CR33 Stub Ends
Corrosion Resistance
ASTM A815 CR33 fittings provide outstanding resistance to:
Chloride pitting and crevice corrosion
Stress-corrosion cracking (SCC) in chloride environments
Sulfur-containing gases and flue gases
Seawater corrosion & desalination media
Chemical processing environments
Heat Resistance
Excellent resistance to oxidation & scaling up to 1100°C
Superior thermal cycling performance compared to austenitic steel
Recommended for high-temperature furnace components & flue gas ducts
Heat Treatment
Typically delivered cold-worked
Annealing range: 850°C – 950°C
Rapid cooling to maintain ferritic structure
Welding
Good weldability with proper ferritic stainless steel welding techniques
Recommended filler metals: matching ferritic grade (if required)
Preheat: Generally not needed
Post-weld treatment: Annealing may be beneficial in critical service
Fabrication
Good formability & machinability
Higher strength enables reduced thickness designs
Avoid heavy cold-work without intermediate annealing
Applications
Chemical & Petrochemical Industry
Oil & Gas Refineries
Desalination & Marine Systems
Heat Exchangers & Condenser Systems
Flue Gas Desulfurization (FGD) Units
Power Plants & Boilers
Furnace & High-Temperature Systems
Wastewater Treatment Plants