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ASTM B824 is a standard specification for general requirements for copper alloy castings. It covers the material properties, testing methods, and acceptance criteria for various copper alloy castings, including B62 C83600 bronze.
• Material Requirements: Specifies the chemical composition and mechanical properties of copper alloy castings.
• Testing Methods: Outlines various testing methods, including tensile testing, hardness testing, and non-destructive testing (NDT) such as penetrant testing.
• Acceptance Criteria: Provides detailed acceptance criteria for different types of defects, including surface and internal defects.
B62 C83600 Bronze: Properties and Applications
B62 C83600 bronze is a high-strength copper alloy known for its excellent corrosion resistance and mechanical properties.
• Tensile Strength: ≥450 MPa
• Yield Strength: ≥200 MPa
• Elongation: ≥10%
• Hardness: HB 159-280
B62 C83600 bronze is widely used in applications requiring high strength and corrosion resistance, such as:
• Marine and Offshore: Components exposed to seawater, including propeller hubs and valves.
• Chemical Processing: Equipment exposed to corrosive media, such as acids and chlorides.
• Filter Castings: Used in Y-type strainers and other filtration systems.
Penetrant Testing: ASTM B824 Acceptance Criteria
Penetrant testing, also known as liquid penetrant inspection (LPI), is a non-destructive testing method used to detect surface-breaking defects in non-porous materials. The method involves applying a visible or fluorescent penetrant liquid to the surface of the material, allowing it to seep into any surface defects, and then using a developer to make the defects visible under UV light or natural light.
Key Steps in Penetrant Testing
1. Surface Preparation: Clean the surface of the casting to remove any dirt, grease, or other contaminants that could interfere with the testing process.
2. Penetrant Application: Apply the penetrant liquid to the surface of the casting, ensuring complete coverage. Allow the penetrant to dwell for a specified period, typically 10-15 minutes.
3. Excess Penetrant Removal: Remove the excess penetrant from the surface, leaving only the penetrant that has seeped into any surface defects.
4. Developer Application: Apply a developer to the surface to draw out the penetrant from any defects, making them visible.
5. Inspection: Inspect the surface under UV light (for fluorescent penetrants) or natural light (for visible penetrants) to identify any surface-breaking defects.6. Documentation: Document any defects found, including their size, location, and type.
According to ASTM B824, the acceptance criteria for penetrant testing of B62 C83600 bronze castings are as follows:
• Surface Defects: Surface-breaking defects such as cracks, porosity, and inclusions are not acceptable. The maximum allowable size of any single defect is typically specified in the standard or by the customer.
• Internal Defects: Internal defects such as voids and inclusions are also not acceptable. The maximum allowable size and number of internal defects are specified in the standard or by the customer.
• Defect Classification: Defects are classified based on their size, type, and location. Acceptable defect levels are determined based on the specific requirements of the application.
