I. Key material selection and certification standards
1. Analysis of brass alloy composition
Copper-zinc ratio: high-quality brass usually adopts H59/H62 standard (copper content 59%-63%) to ensure the balance between strength and corrosion resistance;
Impurity control: lead content must comply with RoHS 2.0 (≤0.1%) to meet EU environmental protection requirements; impurities such as sulfur and phosphorus must be lower than ASTM B16 standard to prevent intergranular corrosion.
(Buyer's focus: materials directly affect valve life, and material test reports are required)
2. Core certification system
International standards: ISO 9001 (quality management), ISO 14001 (environmentally friendly production);
Industry certification:
NSF/ANSI 61 (drinking water safety, US market access);
WRAS (British Water Compliance Certification);
DVGW (German Gas and Water Industry Association Standard).
(Implicit demand: Certification is the "pass" for export or high-end markets, and the target market requirements need to be clarified)
II. Key durability tests and verification
1. Corrosion resistance test
Salt spray test: ASTM B117 standard, simulates marine or high humidity environment, and no red rust after 720 hours of testing;
Acid medium test: soak in acid solution with pH=5 (simulated industrial wastewater), 30-day surface corrosion rate <0.1mm/year.
2. Mechanical strength verification
Pressure cycle test: EN 12266 standard, 5000 cycles at 1.5 times the nominal pressure (PN16→24bar) without leakage;
Tensile strength: ≥350 MPa (brass body), the connection between the valve stem and the valve body must pass 10,000 opening and closing fatigue tests.
3. Temperature adaptability
High temperature aging: -20℃~150℃ temperature difference impact test (ASTM B584), verify the stability of the sealing material (PTFE/graphite).
3. Process optimization to improve durability
1. Forging process vs. casting process
Forged brass: dense grains, 30% higher compressive strength, suitable for high-pressure scenarios (such as chemical pipelines);
Precision casting: lower cost, but requires X-ray flaw detection (ASTM E505) to detect internal pore defects.
2. Surface treatment technology
Electroplated nickel layer: thickness ≥ 8μm, enhanced wear resistance (in accordance with ASTM B733 standard);
Passivation treatment: chromate passivation film (MIL-C-5541E Class 3), improved salt spray resistance.
4. Long-term stability of the supply chain guarantee
1. Raw material traceability system
Copper ingot suppliers need to provide TÜV SÜD certification, and each batch is accompanied by a material analysis certificate (such as a spectral test report);
Establish a material coding system to achieve full tracking from raw materials to finished products.
2. Aging database and improvement mechanism
Accumulate customer usage data for more than 5 years and analyze typical failure modes (such as valve stem stuck, sealing ring aging);
Targeted improvements: For example, upgrade the valve stem material to silicon brass (C87600) to reduce the friction coefficient.
