Where is the reason for the low hardness of high-precision cold-drawn tubes High-precision fine cold-drawn tube is a kind of high-precision steel tube, which has excellent performance in terms of shape, size and function. However, when testing the fine cold-drawn tube, it will be found that its hardness does not meet the standard requirements and is low. What is the reason for this? In the production process of fine cold-drawn tubes, a high-temperature salt bath furnace is usually used for quenching and heating to achieve deoxidation. However, in practice, complete deoxidation cannot be truly achieved. When it reacts with the carbon on the surface of the fine cold-drawn tube, the phenomenon of insufficient hardness will occur. In addition, the cooling rate during the quenching process has a relatively large effect on the hardness of the fine cold-drawn tube. Generally, the slower the cooling rate, the more the hardness of the product decreases. In order to prevent such phenomena, it is necessary to strictly carry out salt bath deoxidation, and strictly control the cooling temperature and time to obtain satisfactory products.