The core advantage of ASME SA240 S31803 sheet lies in achieving a balance of strength, corrosion resistance, and cost-effectiveness through precise control of the austenite and ferrite phase ratio (ideal ratio approximately 50:50). HT PIPE is a astm sa240 uns s31803 sheet supplier with 15+ export experience. Contact us for more information and quotes for free!
S31803 Mechanical Properties
- Tensile Strength: 620-795 MPa
- Yield Strength: 450-550 MPa
- Elongation: 25%-30%
- Low-Temperature Toughness: Impact energy ≥80 J at -46℃
- Fatigue Performance: Under 200 MPa alternating stress, the fatigue life can reach 10⁷ cycles, suitable for high-frequency load scenarios.
- Hardness: Brinell hardness (HB) ≤270 in the annealed state
duplex uns s31803 Corrosion Resistance
Chloride Environment Resistance: Critical pitting temperature (CPT) ≥35℃, stable performance in environments containing 20,000 ppm chloride, seawater corrosion resistance life exceeding 20 years, suitable for seawater desalination, offshore platforms, and other scenarios.
Stress Corrosion Cracking (SCC) Resistance: Excellent performance in H₂S-containing oil and gas environments, certified to NACE MR0175/ISO 15156 Level II, significantly superior to 304 and 316L stainless steel.
Acid and Alkali Medium Resistance: Resistant to strong acids such as sulfuric acid and hydrochloric acid, as well as alkaline solutions such as sodium hydroxide, suitable for corrosive media treatment scenarios in chemical production.
Intergranular Corrosion Resistance: Low-carbon design combined with reasonable heat treatment processes effectively prevents intergranular corrosion, ensuring the corrosion resistance stability of the sheet during long-term high-temperature use.
duplex stainless steel s31803 plate Physical Properties
- Density: 7.8 g/cm³
- Thermal conductivity: 17 W/(m·K)
- Coefficient of thermal expansion: 14×10⁻⁶/℃
- Continuous service temperature: Upper limit is 250℃, short-term resistance up to 300℃, but prolonged exposure in the 300-525℃ range should be avoided to prevent σ phase precipitation leading to embrittlement.
- Melting point range: 1350-1400℃.
Key Processing Points for S31803 Sheet
astm a240 s31803 sheet Heat Treatment Process
Solution treatment: The core heat treatment process, with temperature controlled at 1040-1080℃ (1050-1100℃ recommended), holding time adjusted according to sheet thickness (30 minutes to 2 hours), followed by water quenching or air cooling, with a cooling rate ≥50℃/s. The purpose is to eliminate processing stress, dissolve precipitated brittle phases, and restore the balance between austenite and ferrite.
Post-weld treatment: When the welding heat input is >1.5 kJ/mm, annealing at 1050℃ for 1 hour is required to eliminate the σ phase in the heat-affected zone and restore corrosion resistance.
Precautions: Cannot be hardened by heat treatment, work hardening can only be achieved through cold working.
duplex s31803 sheet Forming and Processing
Cold Forming: S31803 sheet has good plasticity at room temperature and can be processed by stamping, bending, stretching, etc. However, the work hardening rate is higher than that of 304 stainless steel (approximately 1.2-1.3 times that of 304). When the deformation exceeds 15%-20%, intermediate solution annealing is required to prevent cracking.
Hot Forming: The heating temperature should be controlled at 1050-1200℃ (1100-1150℃ is recommended), and the processing range is 950-1100℃. Good plasticity is achieved in this range, allowing for forging and rolling processes. Rapid cooling (water cooling or forced air cooling) is required after hot working to avoid slow cooling in the 700-900℃ range, which could lead to the precipitation of σ and χ phases.
Forming Limits: The bending radius needs to be larger than that of 304 stainless steel, a bending radius R≥3t (t is the plate thickness) is recommended.
material uns s31803 Welding Process
Welding Characteristics: It has good weldability, but welding without filler metal should be avoided to prevent excessive ferrite formation.
Welding Methods: TIG (Tungsten Inert Gas Welding) and MIG (Metal Inert Gas Welding) are preferred, using ER2209 welding wire.
Parameter Control: Heat input should be controlled at 0.5-1.5 kJ/mm, and 1-2% N₂ can be added to the shielding gas to stabilize the austenite phase.
Post-Weld Inspection: The weld seam needs to be inspected for defects such as cracks and pores. Post-weld heat treatment may be necessary.
duplex stainless steel uns s31803 Machining
Machining Difficulty: Machining difficulty is higher than that of 300 series austenitic stainless steel, requiring higher cutting forces and resulting in faster tool wear.
Tool Selection: Carbide tools (K10-K20) are recommended. CBN tools can be used for finishing to improve surface finish.
Parameter Control: The turning speed should be 80-120 m/min. The machine tool must have high rigidity and the tool must be securely mounted to reduce vibration. The cutting sequence should be designed so that each cutting depth is less than the work-hardened layer produced by the previous cut.
Cutting Method: Flame cutting is prohibited. Plasma cutting or laser cutting is recommended.
