High-strength steel wires such as wire ropes and saw wires are usually manufactured by wire processing high-carbon steel wire rods with a C content of about 0.7~0.9%. Then the wire processing will increase the strength and reduce the ductility, so wire breakage is particularly easy to occur. Due to its high strength, high carbon steel is prone to wire breakage during wire drawing. If the processing strain increases during wire processing, wire breakage during wire processing will significantly reduce production efficiency. Therefore, we need high carbon steel wire rods that are not easy to break during wire rod processing, that is, high carbon steel wire rods with good wire rod processability. Then, let’s learn about wire rod processing and its manufacturing methods and processes!

Steel wire, on the other hand, requires high strength. For example, in order to reduce the weight of tires and improve the fuel consumption of automobiles, steel wire ropes are required to have high strength. In order to meet the strength requirements for these steel wires, high carbon steel is used as the steel raw material. In order to prevent wire breakage when cutting silicon wafers and reduce cutting costs, the saw wires are required to have high strength and thin diameter. In particular, hypereutectoid steel contains a higher amount of c than eutectoid steel.

In hypereutectoid steel, the pre-eutectoid cementite generally precipitates in the hot-rolled wire rod, so the wire drawability of the wire rod is significantly reduced. Therefore, here, in this specification, it is preferable to suppress the precipitation amount of proeutectoid cementite in the eutectoid steel hot-rolled wire rod. "Hot-rolled wire rod" refers to a wire rod in a hot-rolled state that has not been subjected to heat treatment again after hot rolling.

Wire rod processing improves the drawability of hot-rolled wire rods by specifying the pearlite spacing of hot-rolled wire rods. However, Patent Document 1 does not examine the influence of proeutectoid cementite on wire drawability. In addition, the manufacturing process is complicated. Furthermore, there is a step of setting the cooling rate from coiling to a predetermined temperature to 20/second or more and then heating. There are also problems such as a large load on the cooling capacity after coiling and high manufacturing costs.

Wire rod processing improves the wire drawing processability of hot-rolled wire rods by limiting the tensile strength, fracture section shrinkage and ball diameter of hot-rolled wire rods. However, in a wire rod with a high C content, if the fracture surface shrinkage, ball diameter, etc. defined in Patent Document 2 are achieved, the influence of proeutectoid cementite on wire drawability has not been studied, as in Patent Document 1. Otherwise, proeutectoid cementite may precipitate in large amounts and the wire drawing workability will decrease.

Wire rod processing improves the wire drawability by refining the austenite grains of the hot-rolled wire rod and setting the area fraction and aspect ratio of the cooled proeutectoid cementite within specified ranges. The wire rod disclosed in Patent Document 3 is expected to reduce manufacturing costs by further reducing tensile strength, improving wire drawing processability, and reducing load during wire drawing.

Wire processing is carried out to solve the above problems. That is, an object of the present invention is to provide a wire rod and a manufacturing method thereof which contain an amount of c or more than eutectoid steel and which can obtain excellent wire drawability without performing heat treatment of reheating after hot rolling. According to the above structure, it is possible to provide a wire rod containing an amount of c that is equal to or greater than that of eutectoid steel. In addition, according to the above structure, a wire rod having excellent wire drawability can be obtained without performing heat treatment for reheating after hot rolling, and a manufacturing method thereof. The drawability of wire made from hypereutectoid steel can be improved without additional equipment costs. In addition, according to the above-mentioned structure, the wire rod proposed above can suppress cost-increasing factors (increase in the wire breakage rate during wire drawing processing, implementation of intermediate lead bath quenching, molds) accompanying high-strength steel wire ropes, saw wires, etc. increased wear, increased load during wire drawing, etc.). It is useful as a raw material for high-strength steel wires such as saw wires used for cutting steel cables used as reinforcing materials for tires and hoses, and cutting silicon wafers.

The above introduction is about wire processing and its manufacturing methods and processes. If you need to know more, you can contact us at any time!