KR20010060886A - Manufacturing method for electrotinning strip with superior surface appearance and corrsinon resistance - Google Patents

Abstract

PURPOSE: A process for preparing an electrolytic tin plate excellent in surface external appearance and corrosion resistance by controlling roughness of an electrolytic tin plate is provided, which has an effect on preventing increasing the attachment amount to be plated for improving glossiness and reducing manufacturing cost without requiring additional temperature raising. CONSTITUTION: The titled electrolytic tin plate is prepared by the process consisting of: controlling roughness by bright rolling of an electrolytic tin plate on a No 1 temper rolling mill having a roll roughness of 0.10 to 0.15 micrometer and No 2 temper rolling mill having a roll roughness of 0.10 to 0.25 micrometer; and electrolytic degreasing, washing, pickling, washing, electroplating and reflow treating.

Description

MANUFACTURING METHOD FOR ELECTROTINNING STRIP WITH SUPERIOR SURFACE APPEARANCE AND CORRSINON RESISTANCE}

The present invention relates to a method for manufacturing an electro-tin plated steel sheet having excellent surface appearance and corrosion resistance. In detail, the present invention relates to adjusting the roughness of a tin plated plate in the manufacturing process of an electro-tin plated steel sheet of an acid-plating bath containing an additive to improve gloss and stiffness. The present invention relates to a manufacturing method of improving corrosion resistance by improving heat treatment in a reflow alloying process for improving gloss after plating.

In general, in the manufacturing process of tin-plated steel sheet, the tin-plated layer electrodeposited in the acid plating bath to which phenolsulfonic acid (PSA), which is an antioxidant of tin-divalent ions, and an ensa (ENSA) organic additive, which is a brightener, has good adhesion and fineness. Although it forms crystals, the glossiness is low and the plating layer is not dense, thereby showing a rough matte, which is easy to damage the surface.

Such tin plating layer improves workability by lubricating deep processing pipes such as drawing and ironing, but corrosion resistance is lowered due to low hardness of plating layer. Therefore, Fe-Sn alloy layer having excellent corrosion resistance is formed between tin layer and base steel to secure corrosion resistance. In order to improve the glossiness, the strip is heated to a melting temperature of 232 ° C. or more, which is the melting temperature of the tin plated layer, and a rapid cooling treatment is performed to solidify the plating layer until contact with the strip and the roll.

By performing the above-described reflow treatment, the alloy layer is formed of FeSn ² by diffusion of the ferrous iron into the plating layer Sn, thereby improving corrosion resistance and glossiness, and thus, most of the rough steel sheets undergo the above-described process.

However, when the amount of plating adhesion during the above-described process is small, the grinding grooves and the dull grooves generated in the tin-plated disc are transferred as they are after the tin plating, so that the glossiness is deteriorated. In order to solve this problem, it is possible to improve the glossiness to some extent by increasing the amount of plating so that the grinding grooves and less grooves do not appear, but there is a problem that the improvement of the sensibility can be improved. There was a problem in that the rise in the cost of the reflow alloying heat treatment to increase the cost of the rise and the cost of the product due to the rise in energy costs.

In order to solve the above problems, research is being actively conducted to produce high-gloss tin-plated steel sheets without reflow treatment, and Japanese Patent Laid-Open No. 7-216578 discloses tin plating by changing a tin plating solution component added with a surfactant and an aromatic carbonyl compound. A method of manufacturing a steel sheet has been disclosed.

However, the above-described method requires a current density of 100 A / dm ² or more and a plating temperature of 45 ° C. and a flow rate of 200 mpm, and thus cannot be manufactured in a normal manufacturing process. GiS 60 °), not very effective.

In another Patent Publication No. Hei 4-88193, there is a method of manufacturing a tin-plated steel sheet having good gloss by performing a reflow treatment in a conventional manufacturing method to a rapid cooling water temperature of 50 to 75 ° C. and an anodizing in an alkaline solution to perform chrome treatment. In one method, surface staining

(Quench stain) and tin oxide is known to stay at the level of gloss to prevent smudge (Smudge) is a situation that does not meet the manufacture of high gloss, high stiffness and high corrosion-resistant coated steel sheet pursued by the present invention.

Therefore, the technical problem to be achieved by the present invention is to provide a method for producing an electro-tin plated steel sheet having excellent surface appearance and corrosion resistance regardless of the amount of tin plating to solve the above problems.

The configuration for achieving the above technical problem is to maintain the original roughness of 0.15㎛ or less and rolling with a biterite roll so that the unit length and the number of peaks is 5 or less,

It is a reflow treatment consisting of water cooling after a short heat treatment at a tin melting temperature of 232 ° C. or higher.

Hereinafter will be described in detail.

The surface roughness of the original plate is kept below 0.15㎛ to reduce the average roughness, unit length, and roughness peak number in the original plate before the alloy layer amount is increased, and the reflow temperature is maintained above the tin melting point so that the alloy layer structure is spherical. It is used to increase the corrosion resistance by forming it by using two sets of braid rolls to adjust the surface of the disc, and use the roll of less than 0.10 ~ 0.15㎛ of the roughness of the first stage roll and the roughness of the 0.15 ~ 0.25㎛ of the second stage roll. Maintaining the average roughness below 0.15㎛ using the following rolls, and adjusting the roughness of the disc so that the number of peaks per unit length does not exceed 5,

It is composed of a step of immersing in a water tank after a short heat treatment at tin melting temperature of 232 ℃ or more to improve the corrosion resistance.

Adjusting the average roughness less than 0.15㎛ and the number of peaks in the disc roughness adjustment step is to control the roughness of the plated layer and the glossiness and severity are deteriorated. As the remarkably transferred to the plating layer, the glossiness is 80 or less and the sensibility is 90 or less. When the roughness of the plating layer is reflowed at the tin melting temperature or higher at 0.15 µm or less, the alloy layer production amount is 0.8 g / m ² or more, and the structure forms a sphere, thereby improving corrosion resistance. At this time, setting the lower limit of the roughness of the rough rolling roll to 0.15 to 0.25 탆 in the NO 1 roll with 0.1 to 0.15 탆 is caused by the difficulty in forming the roughness of the temper roll. In the conventional tin plating process described above, surface appearance and corrosion resistance are secured without changing tin plating solution concentration, additives, and reflow conditions.

When described in detail by the following examples.

(Example 1)

The low-carbon slag raw carbon cold rolled steel sheet having a thickness of 0.25 mm was temper-rolled by Britroll in two stands of Temper Mill. In the case of the invention, the roughness of the NO 1 roll was set to 0.09 to 0.14 µm and the roughness of the NO 2 roll was 0.15 to 0.25 µm. Set to.

On the other hand, the comparative example maintained the roughness of the NO 1 roll at 0.27 to 0.90 μm and the roughness of the NO 2 roll at 0.15 to 0.65 μm by the conventional method. In both cases, the rough rolled plate was subjected to electrolytic degreasing, rinsing, pickling, rinsing, electroplating, and reflow treatment using the conventional manufacturing method of plated steel sheet. The plating bath solution composition was Sn ++: 35g / L, PSA: 15g / L and ENSA: 3-5 g / L, plating temperature was 35 degreeC, and the current density was maintained at 25 A / dm <^2> .

Moreover, the recrow temperature was performed at 250-260 degreeC which is the temperature above the melting point of tin, and the result shown in Table 1 was obtained.

As shown in Table 1, the comparative example, that is, the roughness of the plated layer of the specimen roughly rolled into the roll with unadjusted roll roughness, the glossiness of 80 or less, the stiffness of 90 or less appeared, and the alloy layer shape showed columnar texture. Therefore, it can be seen that corrosion resistance deteriorates.

On the contrary, in the present invention, the plated rod is good and the glossiness is 80 or more and the stiffness is 90 or more, and the alloy layer has a spherical shape and the corrosion resistance is good.

Therefore, by adjusting the roughness of the original plate before plating it can be seen that it is possible to manufacture a plated steel sheet with good gloss, good clarity and corrosion resistance.

The effect of the present invention is to adjust the roughness of the plate to produce an electro tin plated steel sheet having excellent surface appearance and corrosion resistance irrespective of the tin plating adhesion amount, thereby preventing the increase of the plating adhesion amount for improving the glossiness, as well as reflow alloying accordingly There is no need for additional temperature increase during heat treatment, which reduces cost and removes restrictions on product usage.

Claims (1)

In the conventional electro-tin plated steel sheet manufacturing method of electrolytic degreasing, rinsing, pickling, rinsing, electroplating and reflow plating the raw stone plate, the raw stone plate before the electrolytic degreasing process and the NO1 temper roll having a roll roughness of 0.10 ~ 0.15㎛ Electrolytic tin with excellent surface appearance and corrosion resistance, characterized by plating by electrolytic degreasing, rinsing, pickling, rinsing, electroplating and reflowing after adjusting the roughness by adjusting the roughness to a roll of NO2 roughing roll having 0.01 ~ 0.25㎛ roll roughness Plated steel sheet manufacturing method.