WO2018107473A1

WO2018107473A1 - Annealing and heat treatment method for steel wire

Info

Publication number: WO2018107473A1
Application number: PCT/CN2016/110418
Authority: WO
Inventors: 蔡赛
Original assignee: 蔡赛
Priority date: 2016-12-16
Filing date: 2016-12-16
Publication date: 2018-06-21

Abstract

An annealing and heat treatment method for a steel wire, sequentially comprising steps of: heating, drawing, annealing, tempering, straightening, polishing, and applying an oil. The annealing method for a steel wire comprises steps of: (1) loading a steel wire into a furnace and heating to 450-500°C, and remaining the temperature for 1-2 h; (2) increasing the temperature to 700-750°C at a rate of 60-70°C/h, and remaining the temperature for 1-2h; (3) increasing the temperature to 850-900°C at the rate of 100-120°C/h, and remaining the temperature for 1-2h; and (4) reducing the temperature to 400-450°C at a cooling rate of 100-120°C/h, and removing the steel wire from the furnace. By employing the annealing process, the present invention improves chemical properties and processing properties, eliminates or reduces internal stress, and prepares a superior internal structure for a final heat treatment, thus providing the processed steel wire with excellent mechanical properties.

Description

Steel wire annealing and heat treatment method

Technical field

The present application relates to the technical field of steel wire manufacturing, and in particular to a method for annealing and heat treatment of steel wires.

Background technique

Annealing is a metal heat treatment process that refers to slowly heating a metal to a temperature for a sufficient period of time and then cooling at a suitable rate. The purpose is to reduce hardness, improve machinability, eliminate residual stress, stabilize size, reduce deformation and crack tendency, refine grains, adjust microstructure, and eliminate tissue defects.

For high Mn content steel wires, how to control the annealing temperature and annealing time is an urgent problem to be solved.

Summary of the invention

It is an object of the present invention to provide a method of annealing and heat treating a steel wire to overcome the deficiencies in the prior art.

To achieve the above object, the present invention provides the following technical solutions:

The embodiment of the present application discloses a method for annealing a steel wire, including the steps of:

(1), the furnace is heated to 450 ~ 500 ° C, and then insulated for 1 ~ 2h;

(2), at 60 ~ 70 ° C / h to 700 ~ 750 ° C, heat preservation 1 ~ 2h;

(3), the temperature is raised to 850 ~ 900 ° C at 100 ~ 120 ° C / h, and the temperature is kept for 1 ~ 2h;

(4), cooling at a cooling rate of 100 to 120 ° C / h to 400 ~ 450 ° C, and baked.

Preferably, in the above annealing method of the steel wire, the composition of the heat-treated steel wire is in terms of mass percentage:

C 0.60~0.70;

Mn 0.7 to 1.1;

Si 0.15 to 0.35;

Cr 3.80 ~ 4.40;

V 1.75 to 2.20;

W 5.50~6.75;

Mo4.50~5.50;

P≤0.030;

S ≤ 0.030,

The balance is iron.

Preferably, in the above-described annealing method of the steel wire, the diameter of the steel wire before annealing is 2 mm.

Preferably, in the above annealing method of the steel wire, the annealing process of the steel wire comprises:

(1), the furnace is heated to 500 ° C, and then kept for 2 h;

(2), the temperature is raised to 700 ° C at 70 ° C / h, and kept for 2 h;

(3), the temperature is raised to 850 ° C at 120 ° C / h, and kept for 2 h;

(4), cooled to a temperature of 450 ° C at a cooling rate of 120 ° C / h, and baked.

Correspondingly, the present application also discloses a steel wire heat treatment method, which in turn comprises the steps of: heating-drawing-annealing-tempering-straightening-polishing and oiling, wherein annealing is carried out by the method described.

The advantages of the present invention over the prior art are:

By using the annealing process of the invention, the chemical properties and process properties can be improved, the internal stress can be eliminated, or reduced, and a suitable internal structure can be prepared for the final heat treatment, and the treated steel wire has good mechanical properties.

DRAWINGS

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings to be used in the embodiments or the prior art description will be briefly described below. Obviously, the drawings in the following description are only It is a few embodiments described in the present application, and other drawings can be obtained from those skilled in the art without any creative work.

1 is a flow chart showing a method of heat treatment of a steel wire in a specific embodiment of the present invention;

Figure 2 is a photograph of a metallographic image of annealed steel wire in accordance with a specific embodiment of the present invention.

detailed description

The invention is further illustrated by the following examples, which can be better understood from the following examples. However, those skilled in the art will understand that the specific material ratios, process conditions, and results of the embodiments are merely illustrative of the invention and should not be construed as limiting the invention as described in the claims.

The purpose of steel wire heat treatment includes:

(1) Eliminate the work hardening of the steel wire in the previous cold drawing process to facilitate the continuous cold drawing.

(2) The hot-rolled wire rod has a structure suitable for drawing, and can be drawn normally.

(3), the steel wire has a special structure, and the steel wire after cold drawing has good performance.

(4) Make the finished steel wire have the structure and performance required by the user.

Referring to Figure 1, the heat treatment method of the steel wire includes the steps of:

(1) rapid heating to heat the steel wire to a certain temperature;

(2) The steel wire after high temperature treatment is mechanically drawn to reach a geometric diameter close to crystallizing;

(3) obtaining the strength, toughness and elasticity required for the finished steel wire through annealing and tempering processes;

(4), through the straightening, polishing, oiling to get the finished product.

The annealing process heats the metal that deviates from the equilibrium state to a higher temperature for a period of time and then slowly cools to obtain a process close to the equilibrium state of the structure.

The purpose of annealing is to uniform chemical composition, improve chemical properties and process properties, eliminate or reduce internal stress, and prepare suitable internal structures for the final heat treatment.

In a specific embodiment, the composition of the heat treated steel wire is in terms of mass percentage:

C 0.60~0.70;

Mn 0.7 to 1.1;

Si 0.15 to 0.35;

Cr 3.80 ~ 4.40;

V 1.75 to 2.20;

W 5.50~6.75;

Mo4.50~5.50;

P≤0.030;

S ≤ 0.030,

The balance is iron.

The wire had a diameter of 2 mm before annealing and its initial tensile strength was 1890 MPa.

In a specific embodiment, the annealing process of the steel wire includes:

(1), the furnace is heated to 500 ° C, and then kept for 2 h;

(2), the temperature is raised to 700 ° C at 70 ° C / h, and kept for 2 h;

(3), the temperature is raised to 850 ° C at 120 ° C / h, and kept for 2 h;

Through the annealing process, a heat treatment process close to the equilibrium structure is obtained, and the tensile strength of the steel wire after annealing reaches 1070 MPa.

The microstructure of the annealed steel wire is shown in Fig. 2. As can be seen from the figure, the annealed structure is mainly pearlite structure.

In this context, it is also to be noted that in order to avoid obscuring the invention by unnecessary detail, only the structures and/or processing steps closely related to the solution according to the invention are shown in the drawings, and the Other details that are not relevant to the present invention.

Finally, it is also to be understood that the terms "including", "comprising" or "comprising" or "the" It also includes other elements that are not explicitly listed, or elements that are inherent to such a process, method, item, or device.

Claims

A method for annealing a steel wire, comprising the steps of:

(1), the furnace is heated to 450 ~ 500 ° C, and then insulated for 1 ~ 2h;

(2), at 60 ~ 70 ° C / h to 700 ~ 750 ° C, heat preservation 1 ~ 2h;

(3), the temperature is raised to 850 ~ 900 ° C at 100 ~ 120 ° C / h, and the temperature is kept for 1 ~ 2h;

(4), cooling at a cooling rate of 100 to 120 ° C / h to 400 ~ 450 ° C, and baked.
The method for annealing a steel wire according to claim 1, wherein the composition of the heat-treated steel wire is in terms of mass percentage:

C 0.60~0.70;

Mn 0.7 to 1.1;

Si 0.15 to 0.35;

Cr 3.80 ~ 4.40;

V 1.75 to 2.20;

W 5.50~6.75;

Mo 4.50~5.50;

P≤0.030;

S ≤ 0.030,

The balance is iron.
The method of annealing a steel wire according to claim 1, wherein the wire has a diameter of 2 mm before annealing.
The method for annealing a steel wire according to claim 1, wherein the annealing process of the steel wire comprises:

(1), the furnace is heated to 500 ° C, and then kept for 2 h;

(2), the temperature is raised to 700 ° C at 70 ° C / h, and kept for 2 h;

(3), the temperature is raised to 850 ° C at 120 ° C / h, and kept for 2 h;

(4), cooled to a temperature of 450 ° C at a cooling rate of 120 ° C / h, and baked.
A steel wire heat treatment method comprising the steps of: heating-drawing-annealing-tempering-straightening-polishing and oiling, wherein annealing is performed by the method according to any one of claims 1 to 4.