阅读说明：本技术 一种抑制高强镀锌钢丝镀后扭转性能下降的方法 (Method for inhibiting reduction of torsion performance of high-strength galvanized steel wire after plating ) 是由 王秉喜 郭大勇 高航 张博 潘阳 于 2020-07-08 设计创作，主要内容包括：本发明涉及金属制品加工工艺技术领域,尤其涉及一种抑制高强镀锌钢丝镀后扭转性能下降的方法。具体包括：1)控制锌温与浸锌时间；所述锌温控制在440～460℃,所述浸锌时间控制在10～25秒。2)控制拉拔速度,控制钢丝温升；所述拉拔速度控制在4～8m/s；所述钢丝温升控制在≤120℃。3)控制钢丝碳偏析指数。所述钢丝碳偏析指数为钢丝横截面碳含量最大值与平均值的比值,钢丝碳偏析指数控制在小于1.1。本发明主要适用于高强镀锌钢丝生产,本发明有效抑制了钢丝镀锌过程中造成的扭转性能下降,满足了高强镀锌钢丝对扭转性能的标准要求。(The invention relates to the technical field of metal product processing technology, in particular to a method for inhibiting the reduction of the torsion performance of a high-strength galvanized steel wire after plating. The method specifically comprises the following steps: 1) controlling the zinc temperature and the zinc dipping time; the temperature of the zinc is controlled to be 440-460 ℃, and the zinc immersion time is controlled to be 10-25 seconds. 2) Controlling the drawing speed and the temperature rise of the steel wire; the drawing speed is controlled to be 4-8 m/s; the temperature rise of the steel wire is controlled to be less than or equal to 120 ℃. 3) Controlling the carbon segregation index of the steel wire. The steel wire carbon segregation index is the ratio of the maximum value and the average value of the carbon content of the cross section of the steel wire, and is controlled to be less than 1.1. The invention is mainly suitable for the production of high-strength galvanized steel wires, effectively inhibits the reduction of the torsional property caused in the process of steel wire galvanizing, and meets the standard requirement of the high-strength galvanized steel wires on the torsional property.)

1. A method for inhibiting the reduction of the torsion performance of a high-strength galvanized steel wire after plating is characterized by comprising the following steps:

1) controlling the zinc temperature and the zinc dipping time;

2) controlling the drawing speed and the temperature rise of the steel wire;

3) controlling the carbon segregation index of the steel wire.

2. The method for inhibiting the reduction of the torsion performance of the high-strength galvanized steel wire after being plated according to claim 1, wherein the zinc temperature is controlled to be 440-460 ℃, and the zinc dipping time is controlled to be 10-25 seconds.

3. The method for inhibiting the reduction of the torsion performance of the high-strength galvanized steel wire after being plated according to claim 1, wherein the drawing speed is controlled to be 4-8 m/s; the temperature rise of the steel wire is controlled to be less than or equal to 120 ℃.

4. The method for inhibiting the reduction of the torsion performance of the high-strength galvanized steel wire after being plated according to the claim 1, wherein the steel wire carbon segregation index is the ratio of the maximum value to the average value of the carbon content of the cross section of the steel wire; the steel wire carbon segregation index is controlled to be less than 1.1.

Technical Field

The invention relates to the technical field of metal product processing technology, in particular to a method for inhibiting the reduction of the torsion performance of a high-strength galvanized steel wire after plating.

Background

The high-strength steel wire is made up by using high-quality high-carbon steel wire rod through the processes of soxhlet treatment, acid cleaning, copper plating or phosphorization and cold-drawing. The high-strength steel wire is obtained by cold drawing a hot-rolled wire rod serving as a raw material, the steel wire is subjected to two compression forces and one tensile force in the cold drawing process to generate plastic deformation, the internal metallographic structure is continuously strengthened, and finally a deformation texture is obtained, wherein the tensile strength can reach 2000-3500 Mpa.

In general, high-strength galvanized steel wires need to be subjected to a hot galvanizing process in the production process, and the hot galvanizing process is a process of coating a zinc layer on the surfaces of the steel wires through molten zinc liquid.

The hot galvanizing process can affect the structure performance of steel wires, the torsion performance of the plated steel wires is seriously reduced, the torsion performance is usually reduced from about 25-35 times before plating to 10 times after plating, sometimes even less than 10 times, the torsion performance of a part of the galvanized steel wires can not meet the standard requirement, the steel wires are one of the main difficulties in high-strength galvanized steel wire production, and the reduction trend of the torsion performance is more obvious when the strength of the steel wires is higher, so that the problem is very urgent to solve.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a method for inhibiting the reduction of the torsion performance of the high-strength galvanized steel wire after plating. Effectively inhibits the reduction of the torsion performance caused in the galvanizing process of the high-strength galvanized steel wire, greatly improves the qualification rate of the torsion performance of the high-strength galvanized steel wire and meets the standard requirement of the high-strength galvanized steel wire on the torsion performance.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for inhibiting the reduction of the torsion performance of a high-strength galvanized steel wire after plating specifically comprises the following steps:

1) controlling the zinc temperature and the zinc dipping time;

the temperature of the zinc is controlled to be 440-460 ℃, and the zinc immersion time is controlled to be 10-25 seconds.

2) Controlling the drawing speed and the temperature rise of the steel wire;

the drawing speed is controlled to be 4-8 m/s; the temperature rise of the steel wire is controlled to be less than or equal to 120 ℃.

3) Controlling the carbon segregation index of the steel wire.

The steel wire carbon segregation index is the ratio of the maximum value and the average value of the carbon content of the cross section of the steel wire, and is controlled to be less than 1.1.

Compared with the prior art, the invention has the beneficial effects that:

1. the zinc temperature and the zinc dipping time are main parameters of the galvanizing process, the zinc temperature and the zinc dipping time are designed so as to control the fragmentation and spheroidization of lamellar cementite in the tissue, and the main technical measure for improving the torsion performance of the steel wire is that the zinc temperature is controlled to be 440-460 ℃ and the zinc dipping time is 10-25 seconds.

2. The drawing speed is a main influence factor of temperature rise of the steel wire in the drawing process, the higher the drawing speed is, the higher the temperature rise of the steel wire is, the greater the influence on the torsion performance of the steel wire is, so that the drawing speed is controlled to be 4-8 m/s, and the temperature rise of the steel wire is controlled to be less than or equal to 120 ℃.

3. The heavier the steel wire carbon segregation is, the larger the influence on the steel wire torsion performance is, and the steel wire carbon segregation index (the ratio of the maximum value to the average value of the carbon content of the cross section of the steel wire) is controlled to be less than 1.1.

The invention provides a method for inhibiting the reduction of the torsion performance of a high-strength galvanized steel wire after plating, which is mainly suitable for the production of the high-strength galvanized steel wire.

Detailed Description

The following further illustrates embodiments of the invention, but is not intended to limit the scope thereof:

a method for inhibiting the reduction of the torsion performance of a high-strength galvanized steel wire after plating specifically comprises the following steps:

1) controlling the zinc temperature and the zinc dipping time;

the temperature of the zinc is controlled to be 440-460 ℃, and the zinc immersion time is controlled to be 10-25 seconds.

2) Controlling the drawing speed and the temperature rise of the steel wire;

the drawing speed is controlled to be 4-8 m/s; the temperature rise of the steel wire is controlled to be less than or equal to 120 ℃.

3) Controlling the carbon segregation index of the steel wire.

The steel wire carbon segregation index is the ratio of the maximum value and the average value of the carbon content of the cross section of the steel wire. The carbon segregation index of the steel wire is controlled to be less than 1.1.

The hot galvanizing process is a process of coating a zinc layer on the surface of a steel wire through molten zinc liquid, and can affect the internal microstructure of the steel wire, the cold-drawn steel wire is a fibrous pearlite structure in a stretching state, part of the fibrous pearlite is cracked and spheroidized after hot galvanizing, and dislocation can smoothly slide in ferrite when a cementite is in a single lamellar structure. When the cementite is broken, spheroidized and scattered and distributed in the ferrite, dislocation slip is hindered, if the size of the particle is small, the dislocation can continue to slip after bypassing the particle, and if the size of the cementite particle is large, the dislocation which breaks the continuity of the matrix is large and is difficult to move. When the spheroidization of cementite is more serious, the more granular cementite is, the larger the size is, the more dispersed the distribution is, the larger the resistance to dislocation slip is, and the more difficult the grains are to slip and deform, thereby causing the rapid reduction of the toughness of the material. Meanwhile, microscopic holes are formed around large spherical cementite particles, microscopic defects appear at the interface of two phases of cementite/ferrite, and when the steel wire is twisted, the regions are very easy to become crack sources to cause the steel wire to crack, so that the twisting performance is reduced rapidly. Therefore, the effective process measure for inhibiting the reduction of the torsion performance of the steel wire after plating is to control the cracking and spheroidizing phenomenon of the cementite of the tissue sheet layer in the galvanizing process.

The temperature of the steel wire is rapidly increased due to deformation and friction work in the steel wire drawing process, the average temperature of high-carbon steel drawing in one pass is increased by 100-160 ℃ under the general drawing condition, the temperature accumulation of the steel wire can reach 500-600 ℃ after the steel wire is drawn in multiple passes, and strain age hardening is easily caused, namely, carbon atoms in the steel and carbon atoms decomposed from part of sheet cementite are diffused to a dislocation center to enable dislocation to be more stable, so that the strength and the toughness of the steel wire are increased, and the steel wire is reduced. The strain age hardening phenomenon appears when the temperature of the steel wire reaches 140 ℃ in the drawing process of the high-carbon steel, and the delamination phenomenon appears when the steel wire is twisted at 140 ℃, which shows that the steel wire has gradually cracked and the twisting performance of the steel wire is sharply reduced. The twisting performance of the steel wire can be deteriorated in a short time when the steel wire is at a temperature of more than 140 ℃, so that the twisting performance of the steel wire can be seriously deteriorated if the temperature of the steel wire is not reduced in time when the steel wire leaves the wire drawing machine at a temperature of more than 140 ℃. The strain age hardening is easily caused by the multi-pass temperature rise accumulation of the temperature rise caused by continuous drawing, the drawing speed determines the temperature rise of the steel wire and the cooling time between drawing passes, and the method is an effective measure for controlling the drawing temperature rise.

The fracture morphology is a main index for measuring the torsion performance of the steel wire, and the fracture morphology of the steel wire with excellent torsion performance is a flat fracture, which shows that the steel wire deforms uniformly in the torsion process. The steel wire is subjected to continuous shear stress and expands towards the center of the steel wire when being twisted, and the analysis of the stress condition in the twisting process of the steel wire shows that the surface and the core structure of the steel wire are uniform, so that the uniform stress is favorably realized in the twisting deformation process of the steel wire. The composition of the high-strength steel wire generally has segregation, mainly carbon segregation, so that the core and the surface structure have certain difference, when the segregation is serious, the core can generate cementite, because the plasticity and the toughness of the cementite are poor, the cementite can not bear larger deformation, when the shear stress expands to the center of the steel wire when the steel wire is twisted, the shear strain can not meet the change of the shear stress and breaks, and therefore the effective measure for improving the twisting performance of the steel wire is to control the carbon segregation of the steel wire so as to improve the difference between the core and the surface structure.