阅读说明：本技术 槽钢热镀锌工艺 (Channel steel hot galvanizing process ) 是由 王�华 袁忠才 于 2019-10-31 设计创作，主要内容包括：本发明涉及一种槽钢热镀锌工艺,包括以下步骤：S1、预处理,待加工槽钢进行脱脂处理,对槽钢进行去油,以使槽钢被水浸润为止；S2、对槽钢进行酸洗；S3、预热：S4、热镀锌：S5、钝化：S6、冷却：S7、检验、包装。采用本发明的镀锌工艺,镀锌之后的槽钢,其能够形成致密的复合膜,其能够显著提高热浸镀锌钝化层的耐蚀性。(The invention relates to a hot galvanizing process for channel steel, which comprises the following steps: s1, preprocessing, namely degreasing the channel steel to be processed until the channel steel is soaked in water; s2, carrying out acid washing on the channel steel; s3, preheating: s4, hot galvanizing: s5, passivation: s6, cooling: and S7, checking and packaging. By adopting the galvanizing process, the galvanized channel steel can form a compact composite film, and the corrosion resistance of a hot-dip galvanizing passivation layer can be obviously improved.)

1. A channel steel hot galvanizing technology is characterized by comprising the following steps:

s1, preprocessing, namely degreasing the channel steel to be processed until the channel steel is soaked in water;

s2, carrying out acid washing on the channel steel;

s3, preheating: drying and preheating the pickled channel steel at the preheating temperature of 90-120 ℃;

s4: hot galvanizing: conveying the channel steel to a galvanizing pot for hot galvanizing;

s5, passivation: passivating by using a passivation solution;

s6, cooling: cooling the channel steel by adopting a water cooling mode, wherein the cooling temperature is 50-70 ℃;

and S7, checking and packaging.

2. A hot galvanizing process for channel steel according to claim 1, wherein the pickling in the step 2 comprises rough pickling, high-pressure water washing, fine pickling, water washing, antirust liquid soaking, high-pressure antirust liquid cleaning, blow drying and cavity cleaning;

the temperature of the acid liquor is 25-45 ℃ during rough pickling, and a sponge projectile is adopted to clean the inner cavity of the pipeline.

3. The process of hot galvanizing channel steel as claimed in claim 1, wherein in the step S5, the passivation solution includes aminotrimethylene phosphonic acid 1.2 to 1.8 wt%, phosphate 3.2 to 5.8 wt%, silicone modified epoxy resin 12.0 to 15.0 wt%, boric acid 0.3 to 0.5 wt%, organic acid 2.3 to 2.8 wt%, and water, and the organic acid is one or more selected from citric acid, tartaric acid, malic acid, salicylic acid, and lactic acid.

4. The channel steel hot galvanizing process of claim 3, wherein the organosilicon modified epoxy resin is prepared by the following method: putting epoxy resin E-20 and a butyl titanate catalyst into a three-neck flask provided with a stirrer, a reflux condenser tube and a dropping funnel, heating to 100-120 ℃, and then starting stirring, wherein the mass ratio of the epoxy resin E-20 to the butyl titanate catalyst is 10: 0.1-0.2; then, the following steps of Z6018 organic silicon: slowly dropwise adding a xylene solution of Z6018 organosilicon according to the mass ratio of 1: 2 of E-20, reacting at 200 ℃ for 4.5-5.5 hours, refluxing, condensing, and continuously separating out small molecular compound alcohol and water generated by the reaction to obtain the organosilicon modified epoxy resin.

5. A hot dip galvanizing process for U-steel according to claim 3, wherein in step S4, the temperature of the steel sheet in the plating bath during the hot dip galvanizing operation is 455-465 ℃, the temperature of the plating bath in the zinc pot is 450-460 ℃, the Fe content in the plating bath is less than 0.03%, and the Al content in the plating bath is as follows: 0.21-0.25%, unit speed: 100-110 m/min, the cooling rate of the steel plate is 0%, and the high span temperature is as follows: 235 to 245 ℃.

6. A process for galvanizing a channel steel according to claim 1, wherein the channel steel comprises, in weight percent, C: 0.03 to 0.07%, Mn: 0.01 to 0.03%, Si: 0.19-0.30%, P: 0.006-0.019%, S: 0.009-0.020%, Al: 0.02-0.07%, and the balance of Fe.

Technical Field

The invention relates to the technical field of hot galvanizing channel steel, in particular to a hot galvanizing process for channel steel.

Background

The prior galvanized steel channel has complex galvanizing process in the galvanizing treatment process, secondly, the galvanized steel channel is passivated by most chromates, hexavalent chromium has high toxicity and carcinogenicity in the chromating process and is gradually eliminated by the market, and the prior market adopts chromium-free passivation solution, titanium salt passivation solution, phosphate pseudo-conversion passivation solution and the like, but the corrosion resistance of the zinc-plated steel channel cannot completely meet the practical application requirements.

Secondly, in the current hot dip galvanized steel channel, the adhesion between a zinc coating and the steel channel is low, and the problems of coating pulverization and peeling exist in the processes of steel channel, transportation and welding, and a method for controlling the adhesion between the coating and the steel channel by changing the components of the steel channel or the components of the zinc coating does not exist at present.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: overcomes the defects of the prior art, provides a hot galvanizing process for channel steel, and solves the problems of relatively complex galvanizing process and poor corrosion resistance in the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows: a hot galvanizing process for channel steel comprises the following steps:

s1, preprocessing, namely degreasing the channel steel to be processed until the channel steel is soaked in water;

s2, carrying out acid washing on the channel steel;

s3, preheating: drying and preheating the pickled channel steel at the preheating temperature of 90-120 ℃;

s4: hot galvanizing: conveying the channel steel to a galvanizing pot for hot galvanizing;

s5, passivation: passivating by using a passivation solution;

s6, cooling: cooling the channel steel by adopting a water cooling mode, wherein the cooling temperature is 50-70 ℃;

and S7, checking and packaging.

Further, the acid washing in the step 2 comprises rough acid washing, high-pressure water washing, fine acid washing, water washing, antirust liquid soaking, high-pressure antirust liquid washing, blow-drying and inner cavity cleaning;

the temperature of the acid liquor is 25-45 ℃ during rough pickling, and a sponge projectile is adopted to clean the inner cavity of the pipeline.

Further, in the step S5, the passivation solution is composed of 1.2 to 1.8 wt% of aminotrimethylene phosphonic acid, 3.2 to 5.8 wt% of phosphate, 12.0 to 15.0 wt% of silicone modified epoxy resin, 0.3 to 0.5 wt% of boric acid, 2.3 to 2.8 wt% of organic acid and water, and the organic acid is one or more organic acids selected from citric acid, tartaric acid, malic acid, salicylic acid or lactic acid.

Further, the organic silicon modified epoxy resin is prepared by the following method: putting epoxy resin E-20 and a butyl titanate catalyst into a three-neck flask provided with a stirrer, a reflux condenser tube and a dropping funnel, heating to 100-120 ℃, and then starting stirring, wherein the mass ratio of the epoxy resin E-20 to the butyl titanate catalyst is 10: 0.1-0.2; then, the following steps of Z6018 organic silicon: slowly dropwise adding a xylene solution of Z6018 organosilicon according to the mass ratio of 1: 2 of E-20, reacting at 200 ℃ for 4.5-5.5 hours, refluxing, condensing, and continuously separating out small molecular compound alcohol and water generated by the reaction to obtain the organosilicon modified epoxy resin.

Further, in step S4, in the hot dip galvanizing operation, the temperature of the steel sheet is 455-465 ℃ when the steel sheet is put into the plating bath, the temperature of the plating bath in the zinc pot is 450-460 ℃, the Fe content in the plating bath is less than 0.03%, and the Al content in the plating bath is: 0.21-0.25%, unit speed: 100-110 m/min, the cooling rate of the steel plate is 0%, and the high span temperature is as follows: 235 to 245 ℃.

Further, the channel steel comprises, by weight: 0.03 to 0.07%, Mn: 0.01 to 0.03%, Si: 0.19-0.30%, P: 0.006-0.019%, S: 0.009-0.020%, Al: 0.02-0.07%, and the balance of Fe.

The invention has the beneficial effects that:

the hot galvanizing process is simple, a plurality of repetitive processes are omitted, the working efficiency is improved, and the galvanizing effect is good.

By adopting the galvanizing process, the galvanized channel steel can form a compact composite film, and the corrosion resistance of a hot-dip galvanizing passivation layer can be obviously improved.

By adopting the galvanizing process, the Fe-Al intermediate transition layer between the channel steel and the zinc coating can prevent mutual diffusion between Fe and Zn, the formation of an Fe-Zn alloy layer is reduced, a gamma phase cannot be formed in the coating, the delta phase is relatively thin, the xi phase is less, most of the coating consists of the eta phase, the adhesiveness of the coating of the hot-dip galvanized steel plate is improved, and the phenomena of zinc powder falling, stripping and the like of the coating are reduced;

the grain orientation of the coating of the hot-dip galvanized steel channel is optimized, and the scratch resistance, the wear resistance and the adhesion performance of the coating are obviously improved.

Detailed Description

The invention will now be further described with reference to specific examples.

A hot galvanizing process for channel steel comprises the following steps:

s1, preprocessing, namely degreasing the channel steel to be processed until the channel steel is soaked in water;

s2, carrying out acid washing on the channel steel;

s3, preheating: drying and preheating the pickled channel steel at the preheating temperature of 90-120 ℃;

s4: hot galvanizing: conveying the channel steel to a galvanizing pot for hot galvanizing;

s5, passivation: passivating by using a passivation solution;

s6, cooling: cooling the channel steel by adopting a water cooling mode, wherein the cooling temperature is 50-70 ℃;

and S7, checking and packaging.

Specifically, the acid washing in the step 2 comprises rough acid washing, high-pressure water washing, fine acid washing, water washing, antirust liquid soaking, high-pressure antirust liquid washing, blow-drying and inner cavity cleaning; the temperature of the acid liquor is 25-45 ℃ during rough pickling, and a sponge projectile is adopted to clean the inner cavity of the pipeline.

Specifically, in step S5, the passivation solution includes 1.2 to 1.8 wt% of aminotrimethylene phosphonic acid, 3.2 to 5.8 wt% of phosphate, 12.0 to 15.0 wt% of silicone modified epoxy resin, 0.3 to 0.5 wt% of boric acid, 2.3 to 2.8 wt% of organic acid and water, and the organic acid is one or more organic acids selected from citric acid, tartaric acid, malic acid, salicylic acid and lactic acid.

Specifically, the organic silicon modified epoxy resin is prepared by the following method: putting epoxy resin E-20 and a butyl titanate catalyst into a three-neck flask provided with a stirrer, a reflux condenser tube and a dropping funnel, heating to 100-120 ℃, and then starting stirring, wherein the mass ratio of the epoxy resin E-20 to the butyl titanate catalyst is 10: 0.1-0.2; then, the following steps of Z6018 organic silicon: slowly dropwise adding a xylene solution of Z6018 organosilicon according to the mass ratio of 1: 2 of E-20, reacting at 200 ℃ for 4.5-5.5 hours, refluxing, condensing, and continuously separating out small molecular compound alcohol and water generated by the reaction to obtain the organosilicon modified epoxy resin.

Specifically, in step S4, in the hot dip galvanizing operation, the temperature of the steel sheet is 455-465 ℃ when the steel sheet is put into the plating bath, the temperature of the plating bath in the zinc pot is 450-460 ℃, the Fe content in the plating bath is less than 0.03%, and the Al content in the plating bath is: 0.21-0.25%, unit speed: 100-110 m/min, the cooling rate of the steel plate is 0%, and the high span temperature is as follows: 235 to 245 ℃.

Specifically, the channel steel comprises, by weight: 0.03 to 0.07%, Mn: 0.01 to 0.03%, Si: 0.19-0.30%, P: 0.006-0.019%, S: 0.009-0.020%, Al: 0.02-0.07%, and the balance of Fe.

The hot galvanizing process is simple, a plurality of repetitive processes are omitted, the working efficiency is improved, and the galvanizing effect is good.

Secondly, the surface of the hot-dip galvanized channel steel passivated by zirconium salt, titanium salt or phosphate is easy to form the phenomenon of zinc corrosion in the actual use process, namely the phenomenon of white powder in general; once the situation occurs, the corrosion resistance of the zinc coating is greatly reduced, and the main reason for the situation is that the compactness of the passive film in the prior art is poor, so that water, carbon dioxide and other acids in the air can form electrolyte on the surface of the zinc tube in an alkaline environment, so that zinc on the surface of the zinc tube is formed by a microcell reaction, the zinc corrosion is accelerated, and the service life of the hot galvanized channel steel is seriously shortened. By adopting the passivation process, a compact composite film can be formed, and the corrosion resistance of the passivation layer can be obviously improved.

By adopting the galvanizing process, the Fe-Al intermediate transition layer between the channel steel and the zinc coating can prevent mutual diffusion between Fe and Zn, the formation of an Fe-Zn alloy layer is reduced, a gamma phase cannot be formed in the coating, the delta phase is relatively thin, the xi phase is less, most of the coating consists of the eta phase, the adhesiveness of the coating of the hot-dip galvanized steel plate is improved, and the phenomena of zinc powder falling, stripping and the like of the coating are reduced; the grain orientation of the coating of the hot-dip galvanized steel channel is optimized, and the scratch resistance, the wear resistance and the adhesion performance of the coating are obviously improved.

In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.