阅读说明：本技术 一种焊接性能优异的紧固件耐腐蚀合金镀层 (Corrosion-resistant alloy coating with excellent welding performance for fastener ) 是由 张贤发 于 2019-12-05 设计创作，主要内容包括：本发明公开了一种焊接性能优异的紧固件耐腐蚀合金镀层,其原料配比为：Al含量为3-9wt%,Mg含量为0.03-0.09wt%,Pb含量为0.1-0.3 wt%,Bi含量为0.1-0.2 wt%,稀土含量为0.05-0.15wt%,余量为锌；其中稀土为镧、铈和镨的混合物,三者的质量比为10-20：3-5：1。相比于现有技术,综合性能大大提高,中性盐雾试验4800h后外观评级为9-10级,浸锡试验的上锡面积均大于95%,表明本发明的合金镀层具有优异的耐腐蚀性能和焊接性能。(The invention discloses a corrosion-resistant alloy plating layer of a fastener with excellent welding performance, which comprises the following raw materials in parts by weight: 3 to 9 weight percent of Al, 0.03 to 0.09 weight percent of Mg, 0.1 to 0.3 weight percent of Pb, 0.1 to 0.2 weight percent of Bi, 0.05 to 0.15 weight percent of rare earth and the balance of zinc; wherein the rare earth is a mixture of lanthanum, cerium and praseodymium, and the mass ratio of the lanthanum to the cerium to the praseodymium is 10-20: 3-5: 1. compared with the prior art, the alloy plating layer has the advantages that the comprehensive performance is greatly improved, the appearance rating is 9-10 grades after 4800h of a neutral salt spray test, and the tinning areas of a tin immersion test are all larger than 95%, so that the alloy plating layer has excellent corrosion resistance and welding performance.)

1. The corrosion-resistant alloy coating for the fastener with excellent welding performance is characterized by comprising the following raw materials in parts by weight: 3 to 9 weight percent of Al, 0.03 to 0.09 weight percent of Mg, 0.1 to 0.3 weight percent of Pb, 0.1 to 0.2 weight percent of Bi, 0.05 to 0.15 weight percent of rare earth and the balance of zinc; wherein the rare earth is a mixture of lanthanum, cerium and praseodymium, and the mass ratio of the lanthanum to the cerium to the praseodymium is 10-20: 3-5: 1.

2. the corrosion-resistant alloy plating layer of the fastener with excellent welding performance as claimed in claim 1, wherein the raw material ratio is as follows: 5wt% of Al, 0.06wt% of Mg, 0.2wt% of Pb, 0.15wt% of Bi, 0.1wt% of rare earth and the balance of zinc; wherein the rare earth is a mixture of lanthanum, cerium and praseodymium, and the mass ratio of the lanthanum to the cerium to the praseodymium is 15: 5: 1.

3. the method for treating the corrosion-resistant alloy coating of the fastener with excellent welding performance according to claim 1 or 2, which comprises the following steps:

(1) melting the alloy: heating zinc to 650-750 ℃, wrapping magnesium, lead and bismuth with aluminum sheets, pressing into blocks, pressing into zinc liquid, keeping at 650-750 ℃ for 2h, and stirring with quartz rods every 20min in the process; after the mixture is fully melted, heating to 850-880 ℃, pressing the rare earth into the bottom of a molten pool, keeping the temperature at 850-880 ℃ for 1h, and reducing the temperature to 650-700 ℃ for later use;

(2) fastener pretreatment: keeping the fastener in 10wt% NaOH alkali liquor at 50 ℃ for 3-5min to carry out alkali cleaning and oil removal; then taking out and washing with clear water; then, using 10wt% hydrochloric acid solution to perform acid pickling for 3min to remove rust; then cleaning with clear water; plating assistant agent at 80 deg.C for 1-2 min; then drying the fastener at 105 ℃ for 2 min;

(3) hot dip coating: placing the fastener pretreated in the step (2) into the molten alloy prepared in the step (1), wherein the dip plating temperature is 650-700 ℃, and the dip plating time is 10-20 s;

wherein, the plating assistant agent in the step (2) comprises the following components: ZnCl with concentration of 250-280g/L₂NH with a concentration of 40-60g/L₄Cl, AlCl with concentration of 40-60g/L₃LiCl with the concentration of 30-50g/L, emulsifier OP-10 with the concentration of 4-8g/L and solvent water.

Technical Field

The invention relates to the technical field of fastener surface treatment, in particular to a fastener corrosion-resistant alloy coating with excellent welding performance.

Background

The phenomenon of the material being destroyed after a chemical electrochemical reaction with the surrounding environment is corrosion of the material. The corrosion of the material is spread in various fields of national economy, and great loss is brought to the national economy. The anti-corrosion work of the material is well done, which is not a simple technical problem, but is a series of important social and economic problems of resource protection, energy saving, material saving, environment protection, normal production and personal safety guarantee, new technology development and the like.

The reliability of the fastener as a general-purpose base member plays an important role in the workability and the structural safety of the main machine. In the power industry, a large number of fasteners are used for power transmission line iron towers and hardware connection facilities, so the quality of the fasteners is directly related to the safety and stability of power grid operation.

The most widely used metal in hot-dip coating materials is zinc, and with the development of new industries and science and technology and the increasing severity of environmental pollution, the prior pure zinc coating products can not meet the requirements in the aspects of corrosion resistance, mechanical properties and the like, so the zinc-based alloy coating becomes the main development direction and content of the hot-dip coating industry. Among them, the development of new corrosion-resistant zinc plating is one of the most important development directions in the zinc plating industry. At present, the main method for improving the corrosion resistance of the coating is to deposit an alloy coating on the surface of a steel fastener in the hot dip plating process by adding alloy elements into zinc liquid. The corrosion resistance of the alloy coating is superior to that of a pure zinc coating, so that the corrosion resistance service life of the hot dip coating alloy coating fastener is prolonged, and the requirement of the construction of the whole service life cycle of the power transmission and transformation project is met. In recent years, the zinc coating with excellent corrosion resistance mainly comprises Zn-Al, Zn-Al-Mg and other series, and a novel high-corrosion-resistance Zn-Al-Mg alloy coating of Nisshin Steel works of Japan has 10 times of the corrosion resistance of a pure zinc coating and 5 times of the corrosion resistance of a Galfan alloy coating.

At present, some technical schemes of alloy plating layers have been disclosed in the prior art, for example, chinese patent application with application publication No. CN 104711502A discloses a corrosion-resistant zinc-aluminum-magnesium rare earth alloy plating layer and a preparation and hot-dip plating method thereof, the raw material ratio of the corrosion-resistant zinc-aluminum-magnesium rare earth alloy plating layer is: al3-9wt%, Mg0.03-0.09wt%, rare earth 0.01-0.15wt%, and Zn for the rest. Wherein the rare earth is lanthanum, cerium or praseodymium. Various raw materials are mixed and prepared into molten alloy through an alloy melting step, and the plating solution has good fluidity and good wettability to steel base; after the steel subjected to surface pretreatment is subjected to hot dip coating on the prepared molten alloy, the surface is coated with the corrosion-resistant zinc-aluminum-magnesium rare earth alloy coating, and the coating is flat and smooth in surface and has excellent corrosion resistance. However, the zinc-aluminum-magnesium rare earth alloy plating layer has insufficient weldability and has room for further improvement. Therefore, improvement and innovation are carried out on the basis of the existing alloy plating layer, the corrosion resistance of the alloy plating layer is improved, and meanwhile, the welding performance is also improved, so that the alloy plating layer with more excellent comprehensive performance is obtained.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide an alloy coating with more excellent corrosion resistance and welding performance. Specifically, the invention adopts the following technical scheme:

a corrosion-resistant alloy coating of a fastener with excellent welding performance comprises the following raw materials in parts by weight: 3 to 9 weight percent of Al, 0.03 to 0.09 weight percent of Mg, 0.1 to 0.3 weight percent of Pb, 0.1 to 0.2 weight percent of Bi, 0.05 to 0.15 weight percent of rare earth and the balance of zinc; wherein the rare earth is a mixture of lanthanum, cerium and praseodymium, and the mass ratio of the lanthanum to the cerium to the praseodymium is 10-20: 3-5: 1.

preferably, the corrosion-resistant alloy plating layer of the fastener with excellent welding performance comprises the following raw materials in parts by weight: 5wt% of Al, 0.06wt% of Mg, 0.2wt% of Pb, 0.15wt% of Bi, 0.1wt% of rare earth and the balance of zinc; wherein the rare earth is a mixture of lanthanum, cerium and praseodymium, and the mass ratio of the lanthanum to the cerium to the praseodymium is 15: 5: 1.

the method for obtaining the alloy coating by hot dip coating on the surface of the fastener comprises the following steps:

(1) melting the alloy: heating zinc to 650-750 ℃, wrapping magnesium, lead and bismuth with aluminum sheets, pressing into blocks, pressing into zinc liquid, keeping at 650-750 ℃ for 2h, and stirring with quartz rods every 20min in the process; after the mixture is fully melted, heating to 850-880 ℃, pressing the rare earth into the bottom of a molten pool, keeping the temperature at 850-880 ℃ for 1h, and reducing the temperature to 650-700 ℃ for later use;

(2) fastener pretreatment: keeping the fastener in 10wt% NaOH alkali liquor at 50 ℃ for 3-5min to carry out alkali cleaning and oil removal; then taking out and washing with clear water; then, using 10wt% hydrochloric acid solution to perform acid pickling for 3min to remove rust; then cleaning with clear water; plating assistant agent at 80 deg.C for 1-2 min; then drying the fastener at 105 ℃ for 2 min;

(3) hot dip coating: and (3) placing the fastener pretreated in the step (2) into the molten alloy prepared in the step (1), wherein the dip plating temperature is 650-700 ℃, and the dip plating time is 10-20 s.

Wherein, the plating assistant agent in the step (2) comprises the following components: ZnCl with concentration of 250-280g/L₂NH with a concentration of 40-60g/L₄Cl, AlCl with concentration of 40-60g/L₃LiCl with the concentration of 30-50g/L, emulsifier OP-10 with the concentration of 4-8g/L and solvent water.

Compared with the prior art, the invention has the beneficial effects that: the comprehensive performance is greatly improved, and the corrosion resistance and the welding performance are more excellent. The appearance rating of the alloy coating is 9-10 grades after 4800h of a neutral salt spray test, and the tin coating area of a tin immersion test is larger than 95%, so that the alloy coating has excellent corrosion resistance and welding performance, and a fastener treated by the alloy coating has a wider application prospect.

Detailed Description

The invention is further described below by way of examples.