In the process of using the high precision cold drawn tube, the cold drawn pipe seamless pipe is mainly used as a high-precision steel pipe material for tolerance control and surface bright processing of raw materials. The high precision cold drawn tube has the characteristics of high precision, high smoothness, good cleanness of the inner wall, high pressure and no leakage of the steel tube, no deformation of cold bending, flaring, flattening without cracks, etc., and can be used for various complex deformations and mechanical processing. The chemical composition of the high precision cold drawn tube is carbon C, silicon Si, manganese Mn, sulfur S, phosphorus P, chromium Cr.
Cold and brittle factors of high precision cold drawn tube
The cold brittleness (or low-temperature embrittlement tendency) of the cold-rolled precision bright steel pipe is expressed by the toughness-brittle transition temperature Tc. High purity iron (0.01% C) has a Tc at 100 C. Below this temperature, it is completely in an embrittled state. Most alloying elements in cold-rolled precision bright steel tubes increase the toughness-brittle transition temperature of cold-rolled precision bright steel tubes, increasing the tendency of cold and brittleness. When the ductile fracture occurs above room temperature, the fracture of the cold-rolled precision bright steel pipe is a dimple-type fracture, and the fracture is a cleavage fracture at a low temperature.
Factors of cold and brittle high precision cold drawn tube
(1) Solid solution strengthening elements. Phosphorus increases toughness and brittleness. The transformation temperature is the strongest; there are also molybdenum, titanium and vanadium; the elements with low content and low content and high toughness and brittle transition temperature are silicon, chromium and copper; reducing toughness and brittleness. There is nickel in the conversion temperature, and manganese is firstly lowered to increase the toughness-brittle transition temperature.
(2) Forming the elements of the second phase. In the second phase, the most important element for cold rolling of cold-rolled precision bright steel pipe is carbon. With the increase of carbon content in cold-rolled precision bright steel pipe, the pearlite content in cold-rolled precision bright steel pipe increases, and the average pearlite volume increases by 1%. The toughness-brittle transition temperature increased by an average of 2.2 °C.www.skivingtubelw.com
