Cold drawn tubes have high requirements in production and processing. Due to its high surface temperature, fast shrinkage and fast condensation, the cold-drawn tube is easily affected during the condensation process under the action of heat. In order to obtain good chemical and physical properties, it is necessary to heat-treat cold-drawn tubes.
The faster the cooling rate, the higher the carbon content and alloy composition, the greater the inhomogeneity of plastic deformation and the greater the residual stress. On the other hand, during the heat treatment process, due to the change of the microstructure, that is, the transformation of austenite to martensite, the increase of the specific volume is accompanied by the expansion of the volume of the cold drawn tube, and the phase transformation occurs in each part of the workpiece in sequence, resulting in Different volume growth and structural stress. The change of tissue stress is that the tensile stress on the surface is just opposite to the thermal stress. The microstructural stress is related to the cooling rate, shape and chemical composition of the workpiece in the martensitic transformation zone.
The heat treatment process of the cold-drawn tube is related to the hardness of the high-precision cold-drawn tube, and the volume is also related to its processing technology.
https://www.ht-tube.com/