Hot pressing inlay is a common metallographic inlay method. Generally, the sample is placed in the center of the silo, an appropriate amount of inlay is added, heated, pressurized, and shaped, and then cooled before being taken out. Nowadays, when we use inlay materials, we usually provide inlay process parameters, but sometimes there may be inlay defects. Here are several troubleshooting methods.

1、 Cracking.

Cracking is mainly caused by two major factors.

One reason is the unreasonable size and shape of the sample. Samples that are too large in size and have too sharp edges have fewer connection positions for the inlay blocks, making it easy for these samples to; Cut&# quo; Inlay block. The solution is simple: increase the size of the inlay block and reduce the size of the sample.

The second is that the heating temperature is not high enough and the insulation time is not long enough. The heating temperature is not high enough, and some areas cannot completely melt, making it prone to cracking. The insulation time is not long enough, the internal stress release is incomplete, and cold cracking occurs during cooling. The solution is to increase the heating temperature and extend the insulation time. When conditions permit, reduce the cooling rate appropriately or extend the cooling time.

2、 Fracture.

This situation is mainly caused by moisture in the inlay material, which mixes with water vapor, and during inlay, it expands and produces gas due to heat; Separated” It is caused by inlaid materials. It is recommended to dry the inlay material before use, and it is not recommended to release pressure during the inlay process.

3、 Contraction.

Shrinkage is mainly caused by excessive heating temperature and insufficient cooling. One is to control the heating temperature to avoid excessive thermal expansion of the sample and inlay. Secondly, the cooling process should be sufficient. The cooling time can be appropriately extended to ensure uniform overall temperature and prevent overheating of the core. The cooling process should be completed in a pressurized chamber (silo) to avoid excessive cooling shrinkage deformation.

4、 Deformation or expansion.

Deformation and expansion are mainly caused by insufficient pressure and short insulation time. Properly increasing the pressure and extending the insulation time can ensure the normal and stable shape of the inlay block.

Attention:

Temperature and pressure are two important process parameters, but extending the insulation time can alleviate the problem of insufficient embedding temperature and insufficient embedding pressure.

Although cooling is not that important, the cooling speed should not be too fast to avoid cold cracking and deformation; The cooling time should not be too short to avoid insufficient cooling and excessive core temperature.

The entire process of hot pressing and embedding should be carried out in a pressurized environment.

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