Method for manufacturing high carbon steel wire having excellent drawing property

Abstract

The application discloses a high-carbon steel wire rod manufacturing method with excellent drawing performance, and the chemical components of the high-carbon steel wire rod include C: 0.84-0.90%, Si: 0.15-0.35%, Mn: 0.30-0.60%, P: less than or equal to 0.020%, S: less than or equal to 0.020%, and the rest is Fe and inevitable impurities; and the production process of the high-carbon steel wire rod comprises the following steps: casting blank heating, rolling, water tank cooling, Stelmor cooling, collecting and rolling, bundling and packaging. The final rolling temperature, water tank flow, wire drawing temperature, roller speed, fan air volume and total blowing time are coordinately controlled in the rolling process, so that the high-carbon steel wire rod produced has complete cementite lamellar structure (fracture degree is less than or equal to 10%) and excellent drawing performance (compression rate is greater than or equal to 85%).

Description

Technical Field

[0001] This invention belongs to the field of high carbon steel wire production technology, and specifically relates to a method for manufacturing high carbon steel wire with excellent drawing performance. Background Technology

[0002] High-carbon steel wire generally refers to wire with a carbon content ≥ 0.70%. It is the main raw material for manufacturing products such as steel wire rope, bridge steel wire, tire steel wire, spring steel wire, and prestressed steel wire, and has many advantages such as high strength and good wear resistance. The processing technology of high-carbon steel wire generally includes: wire descaling → drawing → heat treatment → coating (optional) → water tank drawing → twisting, etc. Among these, the drawing process is the most challenging to test the quality of the wire, but the drawing compression rate of existing high-carbon steel wire is generally ≤ 85%. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a simple and low-cost method for manufacturing high-carbon steel wire with excellent drawing performance.

[0004] To achieve the above objectives, this invention provides a method for manufacturing high-carbon steel wire rod with excellent drawing performance. The chemical composition of the high-carbon steel wire rod, by weight percentage, includes C: 0.84~0.90%, Si: 0.15~0.35%, Mn: 0.30~0.60%, P≤0.020%, S≤0.020%, with the remainder being Fe and unavoidable impurities. The production process of the high-carbon steel wire rod is as follows: billet heating → rolling → water tank cooling → Stellmor cooling → coiling → bundling → packaging. During rolling, the final rolling temperature of the wire rod is 850~900℃, and the water tank flow rate during water tank cooling is 300~500 ml / min. l / min, wire spinning temperature is 850~950℃.

[0005] Furthermore, during the Stellmore cooling process, the speed of the Stellmore inlet roller conveyor is 1.0~1.4m / s, the roller speed ratio of the drop section is 0.85~1.0, and the roller speed ratio of the non-drop section is 1.0~1.2.

[0006] Furthermore, during the Steyrmore cooling process, the actual airflow of each fan on the Steyrmore cooling line is 60,000 to 100,000 m³ / h. 3 / h.

[0007] Furthermore, during the Stellmore cooling process, the total blowing time for the wire is 38-48 seconds.

[0008] Furthermore, the diameter of the high-carbon steel wire is 5.5~6.5mm.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: By coordinating and controlling the final rolling temperature, water tank flow rate, wire drawing temperature, roller speed, fan air volume, and total blowing time during the rolling process, the present invention produces high-carbon steel wire rods with complete cementite lamellar structure (fracture degree ≤10%) and excellent drawing performance (compression rate ≥85%). Moreover, the method is simple and has low production cost, and can realize the mass production of high-carbon steel wire rods by utilizing existing high-speed wire rod mills, cooling water tanks, Steyrmore fans, rollers, etc. Attached Figure Description

[0010] Figure 1 A statistical result of the degree of cementite lamellar fracture in high-carbon steel wire under different compression ratios; Figure 2 A graph showing the degree of cementite lamellar fracture (>10%, ×10000) in high-carbon steel wire with a compression ratio <85%; Figure 3 A graph showing the degree of cementite lamellar fracture in high-carbon steel wire with a compression ratio > 85% (<10%, ×10000). Figure 4 This is a microstructure (×10000) image of Example 1; Figure 5 The image shows the microstructure (×10000) of Example 2. Detailed Implementation

[0011] The present invention will now be described in further detail with reference to specific embodiments, so that those skilled in the art can understand it.

[0012] The chemical composition of the high-carbon steel wire of this invention, by weight percentage, includes C: 0.84~0.90%, Si: 0.15~0.35%, Mn: 0.30~0.60%, P≤0.020%, S≤0.020%, with the remainder being Fe and unavoidable impurities; the diameter of the high-carbon steel wire is 5.5~6.5mm.

[0013] High-carbon steel wire with excellent drawing performance possesses both a high drawing compression ratio (≥85%) and a low wire breakage rate, thus reducing processing costs and increasing wire strength. To identify key product characteristics affecting drawing performance, this invention focuses on comparing and analyzing the cementite lamellar properties of high-carbon steels with different drawing performance characteristics, based on the ferrite / cementite lamellar structure of high-carbon steel wire. The results show that one of the key characteristics affecting the drawing performance of high-carbon steel is the degree of cementite lamellar fracture (statistical results are shown in...). Figure 1 Typical images comparing the degree of cementite lamellar fracture in high-carbon steel wires with different drawing properties are shown below. Figure 2 , Figure 3Studies have shown that the basic structural units of high-carbon steel wire are ferrite and cementite. Ferrite is a soft phase, while cementite is a hard phase. During drawing, the wire is subjected to compressive and tensile stresses. Ferrite, being softer, has good plasticity and is less prone to breakage, while cementite, being harder, has poor plasticity and is more prone to breakage. When the cementite lamellar fracture is extensive, the sharp-angle effect during drawing leads to more microcracks at the cementite fracture sites. The propagation of these microcracks increases the likelihood of drawing failure. Statistical results show that when the cementite lamellar fracture degree is ≤10%, high-carbon steel wire exhibits excellent drawing performance (see...). Figure 1 ).

[0014] The main processes affecting the lamellar structure of cementite in high-carbon steel are rolling, water tank cooling, and Stellmore cooling. The key factors influencing the lamellar structure in these processes, including personnel, machinery, materials, and environment, are: final rolling temperature, water tank flow rate, wire drawing temperature, roller speed (including entrance roller speed, drop section speed ratio, and non-drop section speed ratio), fan air volume, and total blowing time (the process flow analysis results are shown in Table 1). In other words, to obtain a lamellar structure with a fracture degree ≤10%, it is necessary to coordinate and control the final rolling temperature, water tank flow rate, wire drawing temperature, roller speed, fan air volume, and total blowing time during the high-carbon steel rolling process.

[0015] Table 1 Process Flow Analysis The influence of the above factors on the degree of cementite lamellar fracture in high carbon steel was discovered through experiments, and the results are shown in Table 2.

[0016] Table 2 Test Results Therefore, the final rolling temperature of the wire rod during rolling is 850~900℃; the water tank flow rate during cooling is 300~500. l The wire drawing temperature is 850~950℃; during the Steyrmore cooling process, the Steyrmore inlet roller speed is 1.0~1.4m / s, the roller speed ratio in the drop section is 0.85~1.0, and the roller speed ratio in the non-drop section is 1.0~1.2. The actual air volume of each fan on the Steyrmore cooling line is 60,000~100,000 m³ / min. 3 When the total blowing time is 38~48s / h, the degree of cementite lamellar fracture is optimally controlled.

[0017] This invention aims to improve the drawing performance of high-carbon steel wire by coordinating and controlling the final rolling temperature, water tank flow rate, wire drawing temperature, roller speed, fan air volume, and total blowing time during the rolling process. The resulting high-carbon steel wire exhibits a complete cementite lamellar structure (fracture degree ≤10%) and excellent drawing performance (compression ratio ≥85%). This method is simple and has low production costs. It utilizes existing high-speed wire rod mills, cooling water tanks, Stellmore fans, rollers, etc., and achieves mass production of high-carbon steel wire by coordinating and controlling the wire temperature, water tank flow rate, fan air volume, and roller speed.

[0018] Example 1 Chemical composition (by weight percentage): C: 0.87%, Si: 0.22%, Mn: 0.48%, P: 0.010%, S: 0.008%, with the remainder being Fe and unavoidable impurities.

[0019] Process flow: billet heating → rolling → water tank cooling → Steyrmo cooling → coiling → bundling → packaging.

[0020] Wire diameter: φ5.5mm.

[0021] The actual final rolling temperature is 850~870℃.

[0022] The actual water tank flow rate is 200~300 l / min.

[0023] The actual spinning temperature is 850~890℃.

[0024] The actual speed of the Stellmo entrance roller conveyor is 1.25 m / s, the roller speed ratio of the drop section is 0.92, and the roller speed ratio of the non-drop section is 1.05.

[0025] The actual air volume of each fan is 80,000 m³. 3 / h, the total blowing time for the wire is 41s.

[0026] The actual degree of cementite lamellar fracture is approximately 6% (see tissue photograph). Figure 4 ).

[0027] Actual drawing performance: The wire was drawn from 5.5mm to 1.7mm (compression rate of approximately 90.4%).

[0028] Example 2 Chemical composition (by weight percentage): C: 0.86%, Si: 0.25%, Mn: 0.50%, P: 0.011%, S: 0.007%, with the remainder being Fe and unavoidable impurities.

[0029] Process flow: billet heating → rolling → water tank cooling → Steyrmo cooling → coiling → bundling → packaging.

[0030] Wire diameter: φ6.5mm.

[0031] The actual final rolling temperature is 880~900℃.

[0032] The actual water tank flow rate is 400~500 l / min.

[0033] The actual spinning temperature is 890~920℃.

[0034] The actual speed of the Stellmo entrance roller conveyor is 1.22 m / s, the roller speed ratio of the drop section is 0.90, and the roller speed ratio of the non-drop section is 1.10.

[0035] The actual air volume of each fan is 98,000 m³. 3 / h, the total blowing time for the wire is 52s.

[0036] The actual degree of cementite lamellar fracture is approximately 9% (see tissue photograph). Figure 5 ).

[0037] Actual drawing performance: The wire was drawn from 6.5mm to 2.1mm (compression rate of approximately 89.6%).

Claims

1. A method for manufacturing high-carbon steel wire with excellent drawing performance, wherein the chemical composition of the high-carbon steel wire, by weight percentage, includes C: 0.84~0.90%, Si: 0.15~0.35%, Mn: 0.30~0.60%, P≤0.020%, S≤0.020%, with the remainder being Fe and unavoidable impurities; the production process of the high-carbon steel wire is as follows: billet heating → rolling → water tank cooling → Steyrmo cooling → coiling → bundling → packaging; characterized in that: The final rolling temperature of the wire rod is 850~900℃, and the water tank flow rate is 300~500 during cooling. l / min, wire spinning temperature is 850~950℃; During the Steyrmo cooling process, the inlet roller speed is 1.0~1.4 m / s, the roller speed ratio in the drop section is 0.85~1.0, and the roller speed ratio in the non-drop section is 1.0~1.2; during the Steyrmo cooling process, the actual air volume of each fan on the Steyrmo cooling line is 60,000~100,000 m³ / s. 3 / h; During the Stellmore cooling process, the total blowing time for the wire is 38~48s.

2. The method for manufacturing high-carbon steel wire with excellent drawing properties according to claim 1, characterized in that: The diameter of the high-carbon steel wire is 5.5~6.5mm.

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