METALLURGICAL SAMPLE PREPARATION

MICROSCOPY AND SEM SAMPLES

Accurate metallurgical testing relies on precise preparation of metal samples, known as metallurgical specimen preparation or metallographic sample preparation. This process is essential for evaluating the microstructure of materials using techniques such as optical microscopy and scanning electron microscopy (SEM). It is crucial that all sample preparation, including SEM sample preparation, is performed with care and attention to detail to ensure clear and accurate imaging.

COMPLETE IN-HOUSE SAMPLE PREPARATION

At Zhejiang Guojian Testing Technology Co., Ltd (CCT) in China, we have the necessary expertise and equipment to provide comprehensive in-house metallurgical sample preparation services. Our capabilities cover a wide range of optical microscopy services, including:

· Extent of decarburization and carburization

· Grain size

· Intergranular attack

· Depth of alpha case in titanium alloys

· Percent spheroidization

· Inclusion rating

· Volume fraction of various phases or second phase particles in metals

· Evaluation of welds

· Evaluation and identification of typical microstructures of metals to confirm structure or property relationships (e.g. tempered martensite in steels)

SEM sample preparation is also provided for all SEM-EDS analysis services.

Zhejiang Guojian Testing Technology Co., Ltd (CCT)  CAPABILITIES

Complete Sample Preparation including SEM and microscopy sample preparation.

· Precision Cutting

· 1.5″ & 2″ Standard Mounts

· Nonstandard Mounting

· Thermoset & Thermoplastic Mounting

· Cold Mounting

· Automatic Grinding & Polishing

· Immersion, Swab & Electrolytic Etching

THE SAMPLE PREPARATION PROCESS

At Zhejiang Guojian Testing Technology Co., Ltd (CCT) , we carry out metallographic specimen preparation in several steps, which include:

Selection of a representative sample to ensure accurate characterization of the microstructure or features of interest. Before beginning the preparation process, it is important for customers to provide information on the orientation or rolling direction of the test specimen.

Careful sectioning of the test sample to avoid altering or destroying its structure. Abrasive sawing or electric discharge machining can cause some deformation on the sample surface, which must be removed during subsequent preparation steps.

Mounting the sectioned specimen in a plastic or epoxy material to facilitate handling during the grinding and polishing steps. The mounting media must be compatible with the sample in terms of hardness and abrasion resistance.

Grinding with a water-lubricated abrasive wheel to achieve a flat, smooth, and scratch-free surface. This step removes surface damage caused during sectioning, and includes the use of a series of progressively finer abrasive grits.

Polishing the sample to remove the last thin layer of deformed metal for a smooth reflective surface. This prepares the sample for examination of unetched characteristics, such as inclusion content or porosity.

Optional etching in an appropriate acidic or basic solution to bring out the microstructural details of the test sample. This step reveals features such as grain boundaries, twins, and second phase particles that may not be visible in the unetched sample.