阅读说明：本技术 一种桥梁缆索用环氧涂层钢丝及其生产工艺 (Epoxy coating steel wire for bridge cable and production process thereof ) 是由 王志永 李鹏 张延旭 于 2021-08-16 设计创作，主要内容包括：本申请涉及桥梁缆索的技术领域,具体公开了一种桥梁缆索用环氧涂层钢丝及其生产工艺。一种桥梁缆索用环氧涂层钢丝,包括钢丝本体和涂层,所述涂层由环氧粉末加热固化制得,所述环氧粉末由包括以下质量份数的原料混合得到,环氧树脂：80-100份,所述环氧树脂的粒径为30-60μm；氧化锡：10-20份,所述氧化锡的粒径为30-70nm；其制备方法为：盘条检测、酸洗、磷化、拉丝、稳定化处理和环氧粉末涂覆。本申请的环氧涂层钢丝可用于桥梁缆索的生产,其具有高耐久性的优点；另外,本申请的制备方法具有提高环氧涂层钢丝使用寿命的优点。(The application relates to the technical field of bridge cables, and particularly discloses an epoxy coating steel wire for a bridge cable and a production process thereof. The epoxy coating steel wire for the bridge cable comprises a steel wire body and a coating, wherein the coating is prepared by heating and curing epoxy powder, the epoxy powder is prepared by mixing the following raw materials in parts by mass: 80-100 parts of epoxy resin, wherein the particle size of the epoxy resin is 30-60 mu m; tin oxide: 10-20 parts of tin oxide, wherein the particle size of the tin oxide is 30-70 nm; the preparation method comprises the following steps: wire rod detection, acid cleaning, phosphating, wire drawing, stabilizing treatment and epoxy powder coating. The epoxy coating steel wire can be used for producing bridge cables and has the advantage of high durability; in addition, the preparation method has the advantage of prolonging the service life of the epoxy coating steel wire.)

1. The epoxy coating steel wire for the bridge cable is characterized by comprising a steel wire body and a coating, wherein the coating is prepared by heating and curing epoxy powder, and the epoxy powder is prepared by mixing the following raw materials in parts by weight:

epoxy resin: 80-100 parts of (by weight),

the particle size of the epoxy resin is 30-60 mu m;

tin oxide: 10-20 parts of (by weight),

the particle size of the tin oxide is 30-70 nm.

2. The epoxy-coated steel wire for bridge cables as claimed in claim 1, wherein: the epoxy powder also comprises 10-20 parts of activated carbon.

3. The epoxy-coated steel wire for bridge cables as claimed in claim 2, wherein: the particle size of the active carbon is 10-20 μm.

4. The epoxy-coated steel wire for bridge cables as claimed in claim 2, wherein: the epoxy resin is modified by octadecylamine in a hydrophobic manner.

5. A process for producing an epoxy-coated steel wire for a bridge cable according to any one of claims 2 to 3, comprising the steps of:

s1, detecting the wire rod: selecting a wire rod with the diameter of 10mm-15mm as a raw material for manufacturing the steel wire;

s2, acid washing and phosphating: carrying out acid washing, water washing and phosphating treatment on the steel wire in sequence;

s3, drawing: continuously drawing the phosphatized steel wire for nine times, controlling the drawing speed V =3.5-4.0m/s, and ensuring that the wire temperature does not exceed 70-80 ℃ of critical temperature in the steel wire drawing process to obtain the steel wire with the diameter of 7.01+0.025 mm;

s4, stabilizing treatment: controlling the heating temperature to be 380-400 ℃, setting the tension to be 3000kg and the linear velocity to be 150m/min, and obtaining the steel wire after the stabilization treatment;

and S5, coating with epoxy powder.

6. The process for producing an epoxy-coated steel wire for a bridge cable according to claim 5, wherein the epoxy powder coating in S5 comprises the steps of:

(1) cleaning the surface of the steel wire after the stabilization treatment to remove oil stains and impurities on the surface of the steel wire;

(2) continuously heating the steel wire, wherein the heating temperature is controlled to be 230 +/-5 ℃;

(3) spraying the epoxy powder after heating, wherein the spraying amount of the epoxy powder is 50-100 g/min, then carrying out water-cooling curing, and roasting the coating again after curing, wherein the heating temperature is 300-;

(4) and baking to obtain the steel wire with the cured epoxy coating.

7. The production process of the epoxy coating steel wire for the bridge cable according to claim 6, wherein the epoxy powder further comprises activated carbon, and the preparation of the epoxy powder comprises the following steps of premixing tin oxide and activated carbon according to a mass ratio of 1:1, and then adding epoxy resin for mixing.

8. The production process of the epoxy coating steel wire for the bridge cable according to claim 7, wherein the epoxy resin added into the epoxy powder is hydrophobically modified epoxy powder, and the hydrophobically modified epoxy resin is prepared by the following steps:

fully mixing 40-60 parts of toluene and 3-7 parts of octadecylamine to obtain a component A; simultaneously, fully mixing 15-20 parts of epoxy resin to be modified and 40-60 parts of toluene solution to be used as a component B; and then dripping the component B into the component A, heating the system to 50-60 ℃ by adopting a water bath heating method, reacting for 20-24h, filtering after the reaction is finished, and drying to obtain the octadecylamine grafted modified epoxy resin, namely the epoxy resin subjected to hydrophobic modification.

Technical Field

The application relates to the technical field of bridge cables, in particular to an epoxy coating steel wire for a bridge cable and a production process thereof.

Background

China is the country with the most cable-stayed bridges, and 6 are in the ranking list of 10 famous cable-stayed bridges in the world. The cable system of the extra-large bridge is a main bearing structure of the bridge, namely a lifeline of the bridge, and the strength and the durability of the stay cable are two key factors determining the safety and the reliability of the lifeline.

In the early and middle stages of the development of cable-stayed bridges in various countries in the world, the protection of the stay cable is also in the grope stage of research and practice. In the 50 to 60 years of the 20 th century, a sealing steel wire rope which is not galvanized is mostly adopted, and a hot cast anchor of a zinc-copper alloy is poured into an anchor cup in an anchoring mode; in the 70 to 80 years, a cold-cast anchor of a non-galvanized parallel steel wire bundle is mostly adopted, and the corrosion prevention condition of the stay cable is PE casing internal pressure cement injection slurry and polymer modified cement slurry; in the 90 s, the multi-protection of a galvanized steel wire or a steel strand and a single-layer and double-layer PE extrusion molding technology and a PE steel strand or an epoxy coating steel strand are adopted. When the stay cable processing technology is adopted, the stay cable corrosion prevention measures are defective, and the stay cable is in a rapidly-developed corrosion damage environment. Most of cable-stayed bridge structures built at early days in China and abroad have the problem of poor durability. With the continuous development of the global bridge cable technology, most of the projects at present have clear requirements on the protection and sealing performance of the stay cable, and the life-span requirement of 50 years to 60 years is provided for the stay cable system.

At present, the production process of the related epoxy coating steel wire for the bridge cable comprises the following steps:

s1, detecting the wire rod;

s2, acid washing and phosphating;

s3, drawing;

s4, stabilizing;

s5, coating epoxy powder;

in view of the above-mentioned related technologies, the inventor believes that the bridge cable is easily corroded by external moisture, oxygen and carbon dioxide during use, and although the epoxy powder is sprayed on the surface of the steel wire to reduce corrosion of the steel wire, after the steel wire is used for a period of time, the epoxy coating is worn to expose the steel wire to air, which results in the reduction of the durability of the steel wire.

Disclosure of Invention

In order to improve the durability of the epoxy coating steel wire, the application provides the epoxy coating steel wire for the bridge cable and the production process thereof.

First aspect, the application provides an epoxy coating steel wire for bridge cable, adopts following technical scheme:

the epoxy coating steel wire for the bridge cable comprises a steel wire body and a coating, wherein the coating is prepared by heating and curing epoxy powder, and the epoxy powder is prepared by mixing the following raw materials in parts by weight:

epoxy resin: 80-100 parts of (by weight),

the particle size of the epoxy resin is 30-60 mu m;

tin oxide: 10-20 parts of (by weight),

the particle size of the tin oxide is 30-70 nm.

By adopting the technical scheme, the tin oxide is taken as an inorganic substance, the tin oxide has the characteristic of insolubility in water, and after the tin oxide is added into the epoxy resin, the tin oxide can be heated and cured on the surface of the steel wire body along with the epoxy resin in the steel wire processing process, so that the effects of blocking moisture in air and improving acid and alkali corrosion resistance of the coating are achieved; on the other hand, in the process of heating and curing the epoxy resin, the melting point of the tin oxide is not reached, the tin oxide can improve the wear-resisting strength of the coating, and the condition that the coating on the surface of the steel wire is worn after the steel wire is used for a long time, so that substances such as moisture, carbon dioxide and the like in the air corrode the steel wire body is reduced, and the durability of the epoxy coating steel wire is effectively improved.

Preferably, the epoxy powder also comprises 10-20 parts of activated carbon.

By adopting the technical scheme, the activated carbon is a hydrophobic adsorbent, and is added into the epoxy powder, so that on one hand, the activated carbon adsorbs the tin oxide with smaller particle size, and the agglomeration of the tin oxide is reduced, thereby improving the dispersibility of the tin oxide; on the other hand, after the activated carbon is heated and cured along with the epoxy resin, the corrosion of moisture to the epoxy coating steel wire can be reduced due to the hydrophobic property of the activated carbon.

Preferably, the particle size of the activated carbon is 10-20 μm.

Through adopting above-mentioned technical scheme, the particle diameter of active carbon is greater than the particle diameter of tin oxide, make the surface at the active carbon of absorption that tin oxide can be better, reduce tin oxide's reunion, simultaneously the particle diameter of active carbon is less than epoxy's particle diameter, make epoxy wrap up active carbon and depend on the tin oxide on active carbon surface after the heating and melting, final solidification is on the surface of steel wire body, improve the abrasion resistance of coating, reduce the condition that moisture passed the epoxy coating and cause the corruption to the steel wire simultaneously, improve the durability of coating.

Preferably, the epoxy resin is hydrophobically modified by octadecylamine.

By adopting the technical scheme, octadecylamine is grafted to epoxy resin, the epoxy resin is subjected to hydrophobic modification, and the surface of the coating has good hydrophobicity after the epoxy resin subjected to hydrophobic modification is heated and cured; on the other hand, the introduction of the hydrophobic group further improves the dispersibility of the epoxy resin, improves the compatibility of the epoxy resin and other raw materials of epoxy powder, and reduces agglomeration.

In a second aspect, the application provides a production process of an epoxy coating steel wire for a bridge cable, which adopts the following technical scheme:

a production process of an epoxy coating steel wire for a bridge cable comprises the following steps:

s1, detecting the wire rod: selecting a wire rod with the diameter of 10.00mm-15.00mm as a raw material for manufacturing a steel wire;

s2, acid washing and phosphating: carrying out acid washing, water washing and phosphating treatment on the steel wire in sequence;

s3, drawing: continuously drawing the phosphatized steel wire for nine times, controlling the drawing speed V =3.5-4.0m/s, and ensuring that the wire temperature does not exceed 70-80 ℃ of critical temperature in the steel wire drawing process to obtain the steel wire with the diameter of 7.01+0.025 mm;

s4, stabilizing treatment: controlling the heating temperature to be 380-400 ℃, setting the tension to be 3000kg and the linear velocity to be 150m/min, and obtaining the steel wire after the stabilization treatment;

and S5, coating with epoxy powder.

By adopting the technical scheme, the wire rod is used as a steel wire raw material, and after acid washing, phosphorization, wire drawing, stabilization treatment and epoxy powder coating, the steel wire product with the epoxy coating is obtained by coiling, and has good corrosion resistance and wear resistance.

Preferably, the coating of the epoxy powder in S5 comprises the steps of:

(1) cleaning the surface of the steel wire after the stabilization treatment to remove oil stains and impurities on the surface of the steel wire;

(2) continuously heating the steel wire, wherein the heating temperature is controlled to be 230 +/-5 ℃;

(3) spraying the epoxy powder after heating, wherein the spraying amount of the epoxy powder is 50-100 g/min, then carrying out water-cooling curing, and roasting the coating again after curing, wherein the heating temperature is 300-;

(4) and baking to obtain the steel wire with the cured epoxy coating.

Through adopting above-mentioned technical scheme, before epoxy powder sprays the steel wire, carry out continuous heating to the steel wire earlier, when epoxy powder contacted the steel wire surface, can melt at once and combine with the steel wire, improve bonding ability between coating and the steel wire body. In addition, the epoxy powder is solidified after being sprayed, the coating is heated and baked again, so that one side of the coating, which is far away from the steel wire body, is heated, at the moment, the activated carbon in the coating provides simple substance carbon, the tin oxide and the simple substance carbon react at a high temperature to generate metal tin, the metal tin has good corrosion resistance, and the generated metal tin is melted and fills the pores of the epoxy coating because the melting point of the metal tin is lower than the baking temperature of the coating, so that the solidified epoxy coating has good compactness, meanwhile, a protective layer is formed on the surface of the steel wire after the metal tin is solidified, and the durability of the steel wire with the epoxy coating is further improved.

Preferably, the epoxy powder further comprises activated carbon, and the preparation of the epoxy powder comprises the following steps of premixing tin oxide and activated carbon according to the mass ratio of 1:1, and then adding epoxy resin for mixing.

By adopting the technical scheme, after the tin oxide and the active carbon are premixed, the active carbon adsorbs the tin oxide, so that the tin oxide is attached to the surface of the active carbon, the agglomeration of the tin oxide is reduced, and meanwhile, the tin oxide can be fully combined with the active carbon, so that the tin oxide and the active carbon can react better to generate metal tin during subsequent heating, the metal tin is molten and flows, the compactness of the coating is further improved, and the durability and the service life of the epoxy coating steel wire are improved.

Preferably, the epoxy resin added into the epoxy powder is hydrophobically modified epoxy powder, and the hydrophobically modified epoxy resin is prepared by the following steps:

fully mixing 40-60 parts of toluene and 3-7 parts of octadecylamine to obtain a component A; simultaneously, fully mixing 15-20 parts of epoxy resin to be modified and 40-60 parts of toluene solution to be used as a component B; and then dripping the component B into the component A, heating the system to 50-60 ℃ by adopting a water bath heating method, reacting for 20-24h, filtering after the reaction is finished, and drying to obtain the octadecylamine grafted modified epoxy resin, namely the epoxy resin subjected to hydrophobic modification.

By adopting the technical scheme, the epoxy resin after hydrophobic modification is obtained by grafting the octadecylamine to the epoxy resin, and the epoxy coating formed after the hydrophobic epoxy resin is cured has hydrophobicity, so that the corrosion resistance of the epoxy coating steel wire is improved, and the durability of the epoxy coating steel wire is improved.

In summary, the present application has the following beneficial effects:

1. the wear-resisting strength of the coating can be improved due to the adoption of the tin oxide and the activated carbon, the condition that substances such as water, carbon dioxide and the like in the air corrode a steel wire body due to the fact that the coating on the surface of the steel wire is worn after the steel wire is used for a long time is reduced, and the durability of the epoxy coating steel wire is effectively improved; after the activated carbon is heated and cured along with the epoxy resin, the corrosion of moisture to the epoxy coating steel wire can be reduced due to the hydrophobic property of the activated carbon;

2. according to the preparation process of the epoxy coating steel wire, the high-strength epoxy coating steel wire with the tensile strength of more than or equal to 1860MPa is obtained through the steps of acid washing, phosphorus washing, wire drawing, stabilizing treatment, epoxy powder coating and the like, and the preparation process has high durability;

3. according to the method, after the tin oxide and the activated carbon are premixed, the epoxy resin is added to be mixed to obtain the epoxy powder, when the epoxy powder is sprayed on the surface of the steel wire body, the steel wire is heated firstly, and after the spraying is finished, the steel wire is cooled, solidified and then baked for the second time, so that the tin oxide and the activated carbon react at a high temperature to generate the metal tin, the metal tin is melted to fill the pores of the epoxy coating, the compactness of the epoxy coating is improved, and the epoxy coating steel wire with strong durability is obtained.

Detailed Description

The raw material sources are as follows:

name of raw materials	Suppliers of goods	Goods number/brand
			Epoxy resin	Chongqing Rui ya Biotechnology Ltd	61788-97-4
Tin oxide	Shanghai barge science and technology Limited	18282-10-5
			Activated carbon	Shanghai Jizhi Biochemical Technology Co.,Ltd.	64365-11-3
Octadecaneamine	Shanghai Haohong Biomedical Technology Co.,Ltd.	124-30-1
			Talcum powder	Sigma Aldrich trade, Inc	14807-96-6
Quartz powder	Hubeixinkang pharmaceutical chemical Co., Ltd	7631-86-9

The mass fraction of the chemical components of the wire rod is as follows

	C	Si	Mn	P	S	Cr	Ni	Cu	V
										Mass fraction%	0.88	0.27	0.8	0.012	0.004	0.17	0.01	0.01	0.06

The mechanical properties of the wire rod are as follows

Diameter/mm

Tolerance deviation/mm

Out of roundness/mm

Tensile strength/MPa

Reduction of area/%)

Grade/grade of inclusions

Grain size/grade

14.0

±0.30

≤0.48

1260-1300

After aging is more than or equal to 32

≤1.5

≥8.5

Microstructure of wire rod: the metallographic structure of the wire rod is mainly a thin-sheet sorbite structure, and the sorbite rate is not less than 85%.

Example 1

The epoxy coating steel wire for the bridge cable comprises a steel wire body and a coating, wherein the coating is prepared by heating and curing epoxy powder, and the epoxy powder is prepared by mixing the following raw materials in parts by weight:

epoxy resin: the weight of the mixture is 90kg,

wherein the particle size of the epoxy resin is 30-60 μm;

tin oxide: 15kg of the raw materials are mixed into a mixture,

wherein the particle size of the tin oxide is 30-70 nm.

The epoxy coating steel wire for the bridge cable is obtained by processing the following steps:

s1, detecting the wire rod: selecting a wire rod with the diameter of 14.00mm as a raw material for manufacturing a steel wire;

s2, acid washing and phosphating: putting the steel wire into a pickling tank for pickling and derusting, washing with water after pickling, and then carrying out phosphating treatment in a phosphating tank after washing with water;

s3, drawing: the steel wire enters wire drawing equipment, and is continuously drawn for nine times by combining active stirring lubrication and a rotary cooling die, the drawing speed V =3.5-4.0m/s is controlled, the wire temperature is ensured not to exceed 70-80 ℃ of critical temperature in the steel wire drawing process, and the steel wire with the diameter of 7.01+0.025mm is obtained;

s4, stabilizing treatment: controlling the heating temperature to be 390 ℃, setting the tension to be 3000kg and the linear velocity to be 150m/min, and obtaining the steel wire after the stabilization treatment;

s5, epoxy powder coating: cleaning the surface of the steel wire after the stabilization treatment, removing oil stains and impurities on the surface of the steel wire, continuously heating the steel wire through high-frequency equipment, spraying the epoxy powder prepared by mixing the epoxy resin and tin oxide on the steel wire in a powder room, melting the epoxy powder on the surface of the steel wire, and solidifying the epoxy powder after cooling to form an epoxy coating, wherein the thickness of the epoxy coating is 0.2 +/-0.05 mm;

s6, closing the disk: and rolling the steel wire coated with the epoxy coating to obtain a steel wire product.

Examples 2 to 3

The epoxy coating steel wire for the bridge cable is based on the embodiment 1, and is different in the using amount of tin oxide.

The amounts of the starting materials used in examples 1-3 are shown in Table one.

TABLE 1 raw material amounts for examples 1-3

	Example 1	Example 2	Example 3
				Amount of epoxy resin/kg	90	80	100
Tin oxide dosage/kg	15	10	20

The performance of the epoxy coated steel wires of examples 1-3 was tested using the following test methods and standards, which were as follows:

1. surface properties of epoxy coated steel wire

The epoxy-coated steel wire was tested according to the method specified in GB/T25835-2010 epoxy-coated steel wire for cables.

2. Durability test

The corrosion resistance of the epoxy coated steel wire was tested according to the method specified in GB/T10125-2012 salt fog test for Artificial atmosphere Corrosion test.

The test results are shown in table two.

TABLE II test results for epoxy coated steel wires of examples 1-3

	Technical standard	Example 1	Example 2	Example 3
					Coating thickness/mm	0.13-0.30	0.22	0.23	0.21
Torsional properties	Not less than 10 times (gauge length 100D)	18	16	16
					Adhesion of coating	5d 8 turns, no crack and no peeling	5d 8 turns, no crack and no peeling	5d 8 turns, no crack and no peeling	5d 8 turns, no crack and no peeling
Surface quality	Smooth and uniform, and has no crack, iron dew and burr	Smooth and uniform, and has no crack, iron dew and burr	Smooth and uniform, and has no crack, iron dew and burr	Smooth and uniform, and has no crack, iron dew and burr
					Tensile strength/MPa	≥1860	1885	1880	1881
Time/h of beginning of corrosion in salt spray test	-	13	12.5	12.5

As can be seen from the above table, the durability of the epoxy-coated steel wire of example 1 is better than that of examples 2 and 3, the steel wire rod is used as a steel wire raw material, and after acid pickling, phosphating, wire drawing, stabilizing treatment and epoxy powder coating, the steel wire is coiled to obtain an epoxy-coated steel wire product which has good corrosion resistance and wear resistance, and after the steel wire is used for a period of time, the epoxy coating still has good corrosion resistance, so that the durability of the epoxy-coated steel wire is improved, and the service life of the epoxy-coated steel wire is prolonged.

Example 4

Based on example 1, the epoxy coating steel wire for the bridge cable is characterized in that 15kg of activated carbon is also added into the epoxy powder raw material, and the particle size of the activated carbon is 10-20 mu m.

The preparation method comprises the following steps:

s1, detecting the wire rod: selecting a wire rod with the diameter of 14.00mm as a raw material for manufacturing a steel wire;

s2, acid washing and phosphating: putting the steel wire into a pickling tank for pickling and derusting, washing with water after pickling, and then carrying out phosphating treatment in a phosphating tank after washing with water;

s3, drawing: the steel wire enters wire drawing equipment, and is continuously drawn for nine times by combining active stirring lubrication and a rotary cooling die, the drawing speed V =3.5-4.0m/s is controlled, the wire temperature is ensured not to exceed 70-80 ℃ of critical temperature in the steel wire drawing process, and the steel wire with the diameter of 7.01+0.025mm is obtained;

s4, stabilizing treatment: controlling the heating temperature to be 390 ℃, setting the tension to be 3000kg and the linear velocity to be 150m/min, and obtaining the steel wire after the stabilization treatment;

s5, epoxy powder coating: carrying out surface cleaning treatment on the steel wire after the stabilizing treatment, removing oil stains and impurities on the surface of the steel wire, then continuously heating the steel wire through high-frequency equipment, spraying the epoxy powder mixed with the activated carbon, the epoxy resin and the tin oxide on the steel wire in a powder room, wherein the adding mode of the activated carbon comprises the steps of premixing the tin oxide and the activated carbon according to the mass ratio of 1:1, then adding the epoxy resin, mixing to melt the epoxy powder on the surface of the steel wire, and solidifying the epoxy powder to form an epoxy coating after cooling;

s6, closing the disk: and rolling the steel wire coated with the epoxy coating to obtain a steel wire product.

Wherein the coating of the epoxy powder in S5 comprises the steps of:

(1) cleaning the surface of the steel wire after the stabilization treatment to remove oil stains and impurities on the surface of the steel wire;

(2) continuously heating the steel wire by high-frequency equipment, wherein the heating temperature is controlled to be 230 +/-5 ℃;

(3) heating, spraying the epoxy powder in a spraying room, wherein the spraying amount of the epoxy powder in the spraying room is 80g/min, then performing water-cooling curing, and baking the coating again after curing, wherein the heating temperature is 360 ℃;

(4) and baking to obtain the steel wire with the cured epoxy coating.

Example 5

An epoxy-coated steel wire for a bridge cable is based on example 4, and is characterized in that 10kg of activated carbon is added into an epoxy powder raw material, and the particle size of the activated carbon is 10-20 mu m.

Example 6

An epoxy-coated steel wire for a bridge cable is based on example 4, and is characterized in that 20kg of activated carbon is added into an epoxy powder raw material, and the particle size of the activated carbon is 10-20 mu m.

The epoxy coated steel wires of examples 4-6 were tested using the above test standards and methods

The test results are shown in table three.

TABLE III test results for epoxy coated steel wires of examples 4-6

	Technical standard	Example 4	Example 5	Example 6
					Coating thickness/mm	0.13-0.30	0.25	0.26	0.26
Torsional properties	Not less than 10 times (gauge length 100D)	19	18	18
					Adhesion of coating	5d 8 turns, no crack and no peeling	5d 8 turns, no crack and no peeling	5d 8 turns, no crack and no peeling	5d 8 turns, no crack and no peeling
Surface quality	Smooth and uniform, and has no crack, iron dew and burr	Smooth and uniform, and has no crack, iron dew and burr	Smooth and uniform, and has no crack, iron dew and burr	Smooth and uniform, and has no crack, iron dew and burr
					Tensile strength/MPa	≥1860	1888	1882	1883
Time/h of beginning of corrosion in salt spray test	-	24	23	23

As can be seen by combining examples 4-6 with Table III, the amount of activated carbon added in example 4 is the optimum amount. According to the application, before the epoxy powder is sprayed on the steel wire, the steel wire is continuously heated, and when the epoxy powder contacts the surface of the steel wire, the epoxy powder can be immediately melted and combined with the steel wire, so that the combining capacity between the coating and the steel wire body is improved; in addition, after the epoxy powder is sprayed, the epoxy powder is cured, and the coating is heated and baked again, so that one side of the coating, which is far away from the steel wire body, is heated; at the moment, the activated carbon in the coating provides simple substance carbon, the tin oxide reacts with the simple substance carbon at a high temperature to generate metal tin, the metal tin has good corrosion resistance, the melting point of the metal tin is lower than the baking temperature of the coating, so that the generated metal tin is melted and fills the pores of the epoxy coating, the cured epoxy coating has good compactness, and meanwhile, a protective layer is formed on the surface of the steel wire after the metal tin is cured, so that the durability of the steel wire with the epoxy coating is further improved.

Comparative example 1

An epoxy-coated steel wire for bridge cables is based on example 4, and is characterized in that the activated carbon is replaced by equal amount of quartz powder.

Comparative example 2

An epoxy-coated steel wire for bridge cables, based on example 4, is distinguished by the fact that an equal amount of talc is used instead of activated carbon.

Comparative example 3

An epoxy-coated steel wire for a bridge cable, which is based on example 4, is distinguished in that the particle size of the activated carbon is 200. mu.m.

Comparative example 4

An epoxy-coated steel wire for a bridge cable, which is based on example 4, is distinguished in that the particle size of the activated carbon is 5 μm.

Comparative example 5

An epoxy-coated steel wire for a bridge cable, which is based on example 4, is different from the epoxy-coated steel wire in that the amount of tin oxide is 0.

The epoxy coated steel wires of comparative examples 1-5 were tested using the above test standards and methods

The test results are given in the table below.

TABLE IV test results for epoxy coated steel wires of comparative examples 1 to 5

	Technical standard	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4	Comparative example 5
							Coating thickness/mm	0.13-0.30	0.13	0.13	0.14	0.14	0.13
Torsional properties	≥10 time (gauge length) 100D）	16	15	16	15	13
							Adhesion of coating	5 d-8 turns, no crack, does not peel off	5d 8 turns, no crack Lines, not peeling off	5d 8 circles, slight splitting Lines and slight peeling	5d 8 circles, slight splitting Lines and slight peeling	5d 8 circles, slight splitting Lines and slight peeling	5d 8 circles, slight splitting Lines and slight peeling
Surface quality	Smooth, uniform and without cracks Lines, exposed iron and burrs	Fine cracks	Fine cracks	Fine cracks	Fine cracks	Fine cracks
							Tensile strength/Mpa	≥1860	1862	1860	1867	1868	1855
Salt fogIn the test, start out Time of corrosion/h	-	8	9	8.2	8.5	7.8

As can be seen by combining comparative examples 1-2 and example 4 and combining tables three and four, the durability of example 4 is superior to that of comparative examples 1-2, so that the activated carbon is a hydrophobic adsorbent in the application, and the activated carbon is added into the epoxy powder, so that on one hand, the activated carbon adsorbs tin oxide with small particle size, and the agglomeration of the tin oxide is reduced, thereby improving the dispersibility of the tin oxide, and on the other hand, after the activated carbon is heated and cured along with epoxy resin, the hydrophobic property of the activated carbon can reduce the corrosion of moisture to the epoxy coating steel wire.

The combination of comparative examples 3-4 and example 4 and the combination of the third table and the fourth table shows that the durability of example 4 is better than that of comparative examples 3-4, so that the particle size of the activated carbon in the application is larger than that of tin oxide, the tin oxide can be better adsorbed on the surface of the activated carbon, and the agglomeration of the tin oxide is reduced; meanwhile, the particle size of the activated carbon is smaller than that of the epoxy resin, so that the epoxy resin is heated and melted, then the activated carbon and the tin oxide attached to the surface of the activated carbon are wrapped, and finally the activated carbon and the tin oxide are solidified on the surface of the steel wire body, so that the wear-resisting strength of the coating is improved; meanwhile, the condition that moisture penetrates through the epoxy coating to corrode the steel wire is reduced, and the durability of the coating is improved.

The combination of comparative example 5 and example 4 and the combination of the third and fourth tables shows that the durability of example 4 is superior to that of comparative example 5, so that after the tin oxide is added into the epoxy resin, the tin oxide can be heated and cured on the surface of the steel wire body along with the epoxy resin in the steel wire processing process, and the effects of blocking moisture in the air and improving the acid and alkali corrosion resistance of the coating are achieved; on the other hand, in the process of heating and curing the epoxy resin, the melting point of the tin oxide is not reached, the tin oxide can improve the wear-resisting strength of the coating, and the condition that the coating on the surface of the steel wire is worn after the steel wire is used for a long time, so that substances such as moisture, carbon dioxide and the like in the air corrode the steel wire body is reduced, and the durability of the epoxy coating steel wire is effectively improved.

Example 7

The epoxy coating steel wire for the bridge cable is based on example 4, and is characterized in that the epoxy resin is epoxy resin obtained by hydrophobically modifying octadecylamine.

The preparation method comprises the following steps: mixing 50kg of octadecylamine, and fully mixing toluene and 5kg of octadecylamine to obtain a component A; simultaneously, mixing 18kg of epoxy resin to be modified and 50kg of epoxy resin, and fully mixing with a toluene solution to obtain a component B; and then slowly dripping the component B into the component A, heating the system to 50 ℃ by adopting a water bath heating method, reacting for 24 hours, filtering the solution after the reaction is finished, and drying in a vacuum constant-temperature drying oven for 25 ℃ to obtain the octadecylamine grafted modified epoxy resin, namely the epoxy resin after hydrophobic modification.

The epoxy coated steel wire of example 7 was tested using the test standards and methods described above.

The test results are shown in Table five.

TABLE V test results for example 7 epoxy coated steel wire

	Technical standard	Example 7
			Coating thickness/mm	0.13-0.30	0.23
Torsional properties	Not less than 10 times (gauge length 100D)	18
			Adhesion of coating	5d 8 turns, no crack and no peeling	5d 8 turns, no crack and no peeling
Surface quality	Smooth and uniform, and has no crack, iron dew and burr	Smooth and uniform, and has no crack, iron dew and burr
			Tensile strength/MPa	≥1860	1900
Time/h of beginning of corrosion in salt spray test	-	32

Combining example 7 and example 4 and combining table three and table five, it can be seen that the durability of example 7 is better than that of example 4, so that octadecylamine is grafted onto epoxy resin in the application, the epoxy resin is subjected to hydrophobic modification, and after the epoxy resin subjected to hydrophobic modification is heated and cured, the surface of the coating has good hydrophobicity, and on the other hand, the introduction of hydrophobic groups further improves the dispersibility of the epoxy resin, improves the compatibility of the epoxy resin with other raw materials of epoxy powder, and reduces agglomeration.

Comparative example 6

The epoxy coating steel wire for the bridge cable is based on the embodiment 1, and is characterized in that epoxy resin powder is not sprayed on the steel wire after the steel wire is subjected to wire drawing.

Comparative example 7

An epoxy-coated steel wire for bridge cables, based on example 4, is distinguished in that only epoxy resin is added to the epoxy powder, the epoxy resin having a particle size of 50 μm.

The epoxy coated steel wires of comparative examples 6-7 were tested using the test standards and methods described above.

The test results are shown in Table six.

TABLE VI test results for comparative examples 6-7 epoxy coated steel wire

	Technical standard	Comparative example 6	Comparative example 7
				Coating thickness/mm	0.13-0.30	-	0.22
Torsional properties	Not less than 10 times (gauge length 100D)	13	14
				Adhesion of coating	5d 8 turns, no crack and no peeling	-	5d 8 turns, no crack and no peeling
Surface quality	Smooth and uniform, and has no crack, iron dew and burr	The surface is rough	The surface is smoother
				Tensile strength/Mpa	≥1860MPa	1855	1865
Time/h of beginning of corrosion in salt spray test	-	6	7

As can be seen by combining comparative examples 6-7 and example 1 and combining the second table and the sixth table, the durability of example 1 is superior to that of comparative examples 6-7, so that epoxy powder is heated and cured in the application, the activated carbon provides elemental carbon, tin oxide reacts with the elemental carbon at high temperature to generate metal tin, the metal tin has good corrosion resistance, and the melting point of the metal tin is lower than the baking temperature of the coating, so that the generated metal tin is melted to fill the pores of the epoxy coating, and thus the cured epoxy coating has good compactness, and meanwhile, the protective layer is formed on the surface of the steel wire after the metal tin is cured, and the durability of the epoxy coated steel wire is further improved.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.