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  • Liquid Penetrant Testing

    Liquid penetrant testing, also known as liquid penetrant inspection (LPI) or dye penetrant testing, which refers to the use of highly permeable liquid to penetrate into the surface defect of the component, and then try to make it show the defect. This is a non-destructive testing method for surface defects. It is widely used in surface quality testing of non-porous materials (such as metal, plastic, glass, ceramic and steel parts). According to the different penetrants used, it can be divided into colored penetrating method and fluorescent penetrating method. As a professional reliability third-party testing organization, T,C&A Lab can provide liquid penetrant testing service according to ISO, ASTM standards and industry requirements. Welcome to contact our experts for consultation.

    Liquid penetration testing procedure

    • Pre-cleaning: All surfaces to be inspected should be clean, dry and free of dirt, grease, paint and other coatings.
    • Penetration: Unless otherwise specified, the entire surface of the part should be covered with penetrant. The penetrant is applied by spraying, dipping or other methods to provide the required coverage.
    • Removal of excess penetrant: Water washing, emulsified water washing and solvent cleaning can be used.
    • Drying: Remove surface moisture.
    • Imaging: The thickness of imaging agent is 0.05mm-0.07mm, keep it for 10-15min.
    • Observation: Observe with naked eye or magnifying glass under visible light, this method is suitable for coloring method, and ultraviolet lamp is suitable for fluorescence method.
    • Evaluation.
    • Post-clean: Remove residual penetrant and imaging agent.

    Adaptability of liquid penetration testing

    • Check for surface opening defects of metal, non-metallic parts or materials, such as cracks, porosity, pores, slag inclusion, cold insulation, folding, etc.
    • It is not limited by the chemical composition of the part, the structure of the part, and the shape of the defect.
    • Check magnetic materials and non-magnetic materials.
    • Check ferrous metals, non-ferrous metals, and non-metals.
    • Check welded parts, castings and machined parts.
    • All defects in all directions and shapes on the surface of the part can be checked out with only one flaw detection.

    Applications of penetration testing include but are not limited to

    • Machinery
    • Aviation
    • Aerospace shipbuilding
    • Instrument
    • Pressure vessel
    • Chemical industry

    Standards we test to

    • ASTM E165, ASTM E1219, ASTM E1417, ASTM E1418, ASTM E1208, ASTM E1209, ASTM E1210, ASTM E433, ASTM A903
    • ISO 4987, ISO 3879, ISO 12095, ISO 10893, ISO 3453, ISO 9583

    In addition, the experts in our Liquid Penetrant Testing (PT) Laboratory also provide a variety of custom services as your needs and requirements. Let's discuss the custom services with our experts for free.

    Instruments and data

    Liquid Penetrant Testing
    Instruments and data

    Note: this service is for Research Use Only and Not intended for clinical use.


    T,C & A LAB is an independent lab providing quality or custom testing, characterization and analysis of a variety of materials. Our engaged experts are ready to help you.

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