Several keys to metallographic microscope inspection of metal materials
1. In the past, during the production, maintenance, and heat treatment of steel and parts, metal materials often changed due to process equipment or improper heat treatment operations, causing the products to fail to meet quality standards. This defect can be avoided if metallographic inspection methods are used to guide production and supervise product quality.
2. After steel parts and large castings and forgings are used for a certain period of time or under the action of alternating loads and high temperature changes, the materials will gradually deteriorate, and the microstructure of the materials will change to varying degrees. When this change reaches a certain limit, It may cause accidents such as leakage, deformation or sudden breakage of parts, seriously affecting production. At this time, regular metallographic inspections can be used to check and monitor changes in materials, and reasonable measures can be taken in a timely manner to avoid safety accidents.
3. Metallographic inspection is a very important task in the failure analysis of metal materials, including macroscopic inspection and microscopic inspection, which often includes the following aspects:
(1) Low magnification acid etching inspection. Check the material for internal segregation, looseness, inclusions, pores and other defects; surface folding, sand inclusions, scars and other defects; internal cracks, white spots, overburning, etc.; forging streamlines, welding quality, grinding, etc.
(2) Use sulfur print and phosphor print methods to detect the segregation of sulfur and phosphorus in steel.
(3) Explicit microstructure analysis is used to determine whether the heat treatment or cold working process of the failed part is normal.
(4) Analyze the corrosion, wear, oxidation, and surface work hardening of the failed parts under working conditions.
(5) Determine the nature of the crack based on the crack characteristics on the failed part and the microstructure on both sides of the crack.
(6) Determine whether the material is qualified through the analysis of non-metallic inclusions inside the failed part material.
