Overview
Wire rod is the smallest type of hot-rolled steel section. Under normal circumstances, the hot-rolled round steel supplied in coils with a diameter of 5 to 9 mm in total eight specifications is called wire rod. Wire rods are also called wire rods because they are delivered in coils. Different countries have slightly different concepts of wire rods. In addition to circular cross-sections, wire rods also have other shapes, and their diameters are inconsistent due to different demand and production technology levels. According to the different rolling mills, it can be divided into two types: high-speed wire rod and ordinary wire rod.
Wire rods are generally made of ordinary carbon steel and high-quality carbon steel. According to different steel distribution catalogues and uses, wire rods include ordinary low-carbon steel hot-rolled round wire rods, high-quality carbon steel wire rods, carbon welding rod wire rods, quenched and tempered threaded wire rods, wire rods for wire ropes, and wire rods for piano wires. And stainless steel wire rods, etc.
Classification of wires
According to the chemical composition of steel, wires can be divided into two categories: one is carbon steel, which can be divided into low carbon steel, medium carbon steel and high carbon steel according to the carbon content; the other is alloy steel. At present, the steel types of wire rods are mainly ordinary low-carbon steel, high-quality carbon steel, electrode steel, wire rope steel, stainless acid-resistant steel, heat-resistant steel, rolling bearing steel, etc. more than 30 kinds.
According to the cross-sectional shape, the wire rods are round, square, oval, trapezoidal and special-shaped. There are very few squares, fewer special shapes, and generally more circular sections.
Use of wire
The use of wire is mainly divided into two types: one is for building materials; the other is for drawing raw materials.
Wire rods used as building materials include ordinary low-carbon steel, high-quality carbon steel and carbon spring steel. The varieties are round and threaded, the diameter of 6 to 25 mm is the most used, and the diameter of 28 to 32 mm is often used. As a wire rod of a building material, it is required to ensure the chemical composition and weldability, and the physical properties are required to be uniform and stable, so as to facilitate cold bending, cold drawing and cold drawing. Wires of various specifications and diameters used in construction projects are expected to be delivered in coils, so that they can be arbitrarily cut according to the length to avoid waste.
Although there are many kinds of steel wire as the raw material for wire drawing, the variety is only round. In order to reduce the number of drawing times, the diameter is generally 5 to 9 mm, and wires with a diameter greater than 10 mm are also used for special purposes. As wire drawing raw material, it is required to ensure that the chemical composition and physical properties are uniform and stable, the metallographic structure should be sorbitized as much as possible, the size should be accurate, the surface should be smooth, and the iron oxide scale should be thin and easy to remove.
In general, wire rods are widely used and occupy an important position in the economy. Some wire rods can be used directly after rolling, mainly for reinforcement of reinforced concrete and welded structural parts; some are used as reprocessing raw materials and are used after reprocessing. For example, it can be drawn into various steel wires, then twisted into steel wire ropes, or woven into wire meshes; through hot forging or cold forging into rivets; through cold forging and rolling into bolts, and through various cutting and Heat treatment to make machine parts or tools; winding and heat treatment to make springs, etc.
Technical requirements
As a wire for construction, it must ensure chemical composition and weldability, have certain mechanical properties, and be uniform and stable to facilitate cold bending and load-bearing.
The wire used for drawing is required to ensure uniform and stable chemical composition, metallographic structure and mechanical properties. The metallographic structure is sorbite as much as possible to reduce the number of annealing times during the cold drawing process. In addition, the specifications and dimensions should be accurate, generally less than 12 mm in diameter. The surface should be smooth, the iron oxide scale should be thin and easy to pickle off, and the surface should be free of defects such as ears and folds.
