The common metallographic inspection items for welded components include the following aspects:

1. Weldingseam structure: Observe the structural composition of the welding area, including the grain structure and phase composition of the base material, the deposited layer, and the fusion line, etc.

2. Welding joint quality: Evaluate the quality of the welding joint, including the integrity, uniformity, absence of cracks, pores, etc. of the weld seam.

3. Heat affected zone: Check the structural composition and properties of the heat affected zone of the weld, understand the structural changes and possible effects caused by heat influence.

4. Hardness test: Measure the hardness values of different parts, evaluate the hardness distribution of the welding area, and understand the strength and hardness characteristics of the welded component.

5. Grain size: Measure the grain size, assess the size and distribution of the grains, and understand the grain structure characteristics of the welded component.

6. Phase composition analysis: Use metallographic microscopes and energy spectrum analyzers to analyze the phase composition of the welded component, understand the phase composition of different structures.

7. Welding residual stress: Through residual stress testing methods, evaluate the magnitude and distribution of welding residual stress, understand the stress state of the welded component.

8. Corrosion performance: Conduct corrosion tests, evaluate the corrosion resistance of the welded component, and understand the corrosion behavior of the welded component under different environmental conditions.

The above metallographic inspection items can comprehensively evaluate the microstructure, performance characteristics and quality status of the welded components, providing important references for welding quality control and engineering design.