Low-carbon steel wire for general use is the most productive type of steel wire, and its diameter is between 0.16 and 10 mm. According to the surface state, it can be divided into two kinds: smooth and galvanized, and according to the delivery state, it can be divided into two kinds: cold drawing and annealing.
The tensile strength of cold-drawn steel wire is generally %26le; 635-1000MPa; nail-making is %26le; 540-1320MPa. The larger the wire diameter, the smaller the tensile strength. However, the tensile strength of cold-drawn steel wire for construction shall not be lower than 635MPa. The tensile strength of the annealed steel wire is between 295 and 500 MPa.
When selecting raw materials, considering the flexibility of the steel wire, in order to prevent the tensile strength from being too high, the carbon content of the small wire diameter should be low; but for the larger specification wire for nail making, the raw material with higher carbon content should be used. , so as not to bend the wire during the punch. Generally, when producing smooth steel wire for non-nail making, the wire rod can be drawn by mechanical descaling (see mechanical descaling of wire rod) and without coating treatment (see lubricating carrier).
In the production of nail-making or galvanized steel wire, due to the high requirements on its surface quality, usually after mechanical descaling, the wire rod must be slightly pickled and then treated with yellowing and lime-stained coating before drawing. pull. Due to the good plasticity and low deformation resistance of low carbon steel wire, the total area reduction rate (see area reduction rate) in one drawing stroke can be obtained larger, and the maximum can reach about 95%.
The surface reduction rate of each pass is generally %26le; 35%. General-purpose low-carbon steel wire is used for heat treatment before galvanizing or intermediate heat treatment between drawing steps. Recrystallization annealing is commonly used, and continuous furnace annealing and pit furnace annealing are widely used. Continuous furnace annealing and continuous hot-dip galvanizing or electro-galvanizing constitute continuous operation lines; pit furnace annealing is used in non-continuous production lines.
