The spring steel sheet will have various problems in the process of use, such as: insufficient hardness or too high hardness, some will also produce the same batch of product quality, the hardness of the reed is different, or some are high, Some are low. These problems are mainly due to:
1. The heating temperature of the reed is low, or the holding time is insufficient. In this state, the content of austenite carbon and alloying elements in the reed structure is not enough, and even untransformed pearlite or undissolved ferrite remains in the reed structure, causing the hardness of the reed to not reach after quenching.
2. The heating temperature of the reed is too high, or the holding time is too long, causing the surface of the reed to be decarburized, resulting in lower hardness.
The corresponding solution measures: reasonable control of heating temperature and holding time, and corresponding inspections after quenching to prevent tempering hardness. In addition, the box-type resistance furnace is a mesh belt furnace, which can better solve the problem of uneven hardness of the same batch of reeds.
The reasons for the decrease in hardness of the spring steel reed after tempering are:
1. The hardness of the reed is too low after quenching, resulting in low hardness.
2. The tempering temperature of the reed is too high, and the heat preservation time of the reed is too long, resulting in low hardness of the reed after tempering.
3. The spring steel reed has high hardness. The main reason is that the tempering temperature is low or the holding time is short.
4. Spring steel reeds have different hardness in the same batch, the main reasons are:
A batch of reeds have insufficient hardness and some are high. In addition to technological reasons, heat treatment equipment is also a key influencing factor. Because the reeds are mostly heat-treated in a box-type resistance furnace, the reeds are often bulk packed in metal baskets, and the heating is very uneven, which is one of the important reasons for the uneven hardness of the same batch of reeds.