How to judge the quality of cast iron parts? Teach you a few practical skills

Many customers do not know how to judge product quality when purchasing cast iron parts. Today, we will teach you several practical methods to quickly judge the quality of cast iron parts from three dimensions: appearance, size, and performance.

1、 Appearance quality inspection

1. Surface defect inspection: Observe whether there are defects such as pores, sand holes, shrinkage cavities, cracks, cold shuts, etc. on the surface of the casting, which will directly affect the strength and sealing of the casting. At the same time, check whether there is sand adhesion, burrs, or burrs on the surface, which not only affect the appearance but may also affect subsequent assembly.

2. Surface roughness inspection: For the working surface that needs to be processed, check whether the surface is flat and has no obvious bumps or depressions; For non machined surfaces, check for smoothness, absence of severe oxidation and rust.

2、 Dimensional accuracy check

1. Key dimension measurement: Use tools such as calipers, micrometers, and level gauges to measure the key dimensions of castings, such as length, width, thickness, hole spacing, parallelism, perpendicularity, etc., to see if they meet the requirements of the drawings. Especially for the mating surfaces used for assembly, the dimensional accuracy must strictly meet the standard.

2. Geometric tolerance inspection: For products such as platforms and bed frames, the focus is on checking the flatness and parallelism to ensure that the geometric tolerance of the workpiece is within the industry standard range and avoid affecting subsequent use.

3、 Internal quality and performance assessment

1. Material composition testing: The chemical composition of the casting can be detected by a spectral analyzer to confirm whether it meets the requirements of the brand, especially the content of elements such as carbon, silicon, manganese, sulfur, phosphorus, which directly affects the mechanical properties of the casting.

2. Hardness testing: Use a Brinell hardness tester to test the hardness of castings. Different grades of cast iron have corresponding hardness standards. For example, the hardness of HT250 should be between 180-240HB. Insufficient hardness will affect wear resistance, while excessive hardness will increase processing difficulty.

3. Non destructive testing: For important castings, ultrasonic testing, magnetic particle testing and other methods can be used to check whether there are defects such as shrinkage and cracks inside the castings, ensuring that the internal quality is qualified.