S321 Stainless Steel Equivalent Standard Grades: Corresponds to Chinese grade 1Cr18Ni9Ti, U.S. grades 321, S32100, TP321, and Japanese grade SUS321. Material Properties 2.1 Chemical Composition: Carbon (C) ≤ 0.08%, Silicon (Si) ≤ 1.00%, Manganese (Mn) ≤ 2.00%, Sulfur (S) ≤ 0.030%, Phosphorus (P) ≤ 0.035%, Chromium (Cr): 17.00–19.00%, Nickel (Ni): 9.00–12.00%, Titanium (Ti) ≥ 5×C%. The addition of Ti enhances resistance to intergranular corrosion but makes it unsuitable for decorative components. 2.2 Corrosion Resistance: Exhibits good corrosion resistance in organic and inorganic acids of varying concentrations and temperatures, particularly in oxidizing media. Prolonged heating in temperature ranges prone to chromium carbide formation may degrade corrosion resistance in harsh environments. Generally comparable to S347 in most environments but slightly inferior to annealed S347 in strongly oxidizing conditions. Mechanical Properties: Tensile strength (σb) ≥ 520 MPa, Yield strength (σ0.2) ≥ 205 MPa, Elongation (δ5) ≥ 40%, Reduction of area (ψ) ≥ 50%, Hardness ≤ 187 HB, ≤ 90 HRB, ≤ 200 HV. Offers better ductility and stress rupture resistance than 304 stainless steel at elevated temperatures. Weldability: Good weldability. Ti addition suppresses chromium carbide formation during welding, reducing intergranular corrosion risks. Requires controlled welding parameters (current, voltage, speed). Common methods include TIG and manual arc welding. Fabrication: Suitable for cold/hot working. Cold working may require intermediate annealing due to significant work-hardening. Hot working temperature: 1000–1150°C. Applications: Structural engineering (beams, bridges, transmission towers), industrial equipment (furnaces, reactors, pipelines), and high-temperature components (427–816°C), such as aircraft engine parts. Post-Weld Heat Treatment: Solution treatment (920–1150°C rapid cooling) is recommended for high-temperature or high-stress applications. Stabilization treatment (850–930°C) may be specified. Non-Destructive Testing (NDT): Ultrasonic and radiographic testing for internal defects. Fluorescent magnetic particle testing (enhanced sensitivity for magnetic zones) and penetrant testing for surface defects. S347 Stainless Steel Equivalent Standard Grades: 347, S34700, 0Cr18Ni11Nb. Material Properties 2.1 Chemical Composition: Carbon (C) ≤ 0.08%, Manganese (Mn) ≤ 2.00%, Nickel (Ni): 9.00–13.00%, Silicon (Si) ≤ 1.00%, Phosphorus (P) ≤ 0.045%, Sulfur (S) ≤ 0.030%, Niobium (Nb) ≥ 10×C%, Chromium (Cr): 17.00–19.00%. Nb addition improves resistance to intergranular corrosion. 2.2 Corrosion Resistance: Excellent resistance in acids, alkalis, and salts, with oxidation resistance up to 800°C. Similar to S321 in most environments but slightly superior in aqueous and low-temperature conditions. Designed for high-temperature applications requiring strong anti-sensitization to prevent intergranular corrosion. Mechanical Properties: Solution-treated: Yield strength ≥ 206 MPa, Tensile strength ≥ 520 MPa, Elongation ≥ 40%, Hardness ≤ 187 HB. Superior high-temperature stress rupture and creep resistance compared to 304 stainless steel. Weldability: Good weldability (TIG, submerged arc welding). Nb minimizes intergranular corrosion, but excessive heat input must be avoided. Fabrication: Similar to S321. Cold working requires attention to work-hardening; hot working temperature: 1050–1200°C. Applications: Aerospace, power generation, chemical/petrochemical industries. Common in high-temperature equipment (boilers, heat exchangers). Post-Weld Heat Treatment: Solution treatment is standard. Stabilization may be added for specific requirements. NDT: Similar to S321. Fluorescent magnetic particle and penetrant testing for surface defects. Key Differences & Selection Guidelines Sensitization Resistance: S347 (with Nb) outperforms S321 (with Ti) in post-weld and high-temperature anti-corrosion. Fabrication: S321’s Ti increases cold-working difficulty; S347’s Nb has less impact on workability. Cost: S347 is more expensive due to Nb scarcity. Summary: S347: Preferred for long-term high-temperature stability and weld reliability (e.g., boilers, aerospace). S321: Cost-effective for moderate/low-temperature applications (e.g., structural components, pipelines).

Product Overview 304 stainless steel, an austenitic stainless steel alloy, is renowned for its exceptional corrosion resistance, durability, and versatility. Composed of 18% chromium and 8% nickel (18/8 stainless steel), it is one of the most widely used stainless steel grades globally. Its balanced composition ensures superior performance across diverse environments, making it a cornerstone material in industries ranging from construction to food processing. Key Properties Corrosion Resistance: Resists oxidation and corrosion in mild environments, including exposure to water, acids, and atmospheric conditions. High Temperature Resistance: Maintains strength and stability at temperatures up to 870°C (intermittent) and 925°C (continuous). Formability and Weldability: Easily fabricated into complex shapes and welded without compromising structural integrity. Hygienic Surface: Non-porous and easy to clean, ideal for applications requiring strict hygiene standards. Aesthetic Appeal: Polished or brushed finishes provide a sleek, modern appearance for architectural and decorative uses. Advantages Over Competing Alloys Cost-Effectiveness: Offers a favorable balance between performance and cost compared to higher-grade alloys like 316 stainless steel. Wide Availability: Readily available in various forms (sheets, coils, tubes, bars) to meet diverse manufacturing needs. Sustainability: Fully recyclable, aligning with global efforts toward eco-friendly material practices. Applications Across Industries Food & Beverage: Used in kitchen equipment, storage tanks, and processing machinery due to its non-reactive nature. Architecture & Construction: Ideal for façades, railings, and structural components in both indoor and outdoor settings. Medical Equipment: Employed in surgical tools, sterilization trays, and hospital fixtures for its sterilizable surface. Chemical & Pharmaceutical: Utilized in tanks, piping, and reactors where resistance to corrosive substances is critical. Automotive: Components like exhaust systems and trim benefit from its heat resistance and aesthetic qualities.

The microsand ballasted high-efficiency sedimentation process is a solid-liquid separation clarification technology (similar to traditional sedimentation methods) that physically removes suspended solid particles from water. It also employs physico-chemical removal of dissolved phosphates through the addition of coagulants (aluminum/iron salts). By introducing microsand into the water, flocculation reactions form sand-core flocs, which are ultimately separated from the water. The high density of sand-containing flocs enables rapid settling, resulting in a surface loading rate far exceeding that of conventional high-efficiency sedimentation tanks. Microsand Properties: Material: Natural quartz sand with SiO₂ content > 98%. Particle size (d₁₀): 80–150 μm (adjusted based on application requirements). Density: 2650 kg/m³. Key Advantages: Enhanced Coagulation: Microsand increases collision frequency among particles, improving coagulation efficiency. Rapid Settling: The increased density of flocs accelerates sedimentation, significantly boosting the surface loading capacity of the tank. Sludge Compatibility: Microsand does not cause abrasion to existing sludge treatment systems. Sand-containing sludge can be conventionally disposed of or incinerated without adverse effects.