熱鍍鋅方管是目前鋼材市場上應(yīng)用非常普遍的品種，隨著鍍鋅技術(shù)的進(jìn)步與鍍鋅方管應(yīng)用的推廣，對熱鍍鋅方管表面質(zhì)量的要求也越來越高。其鋅層厚度一般在Z80~Z140之間，其基本控制要點(diǎn)是：

Hot-dip galvanized square tubes are widely used in steel market at present. With the progress of galvanizing technology and the popularization of galvanized square tubes, the requirements for surface quality of hot-dip galvanized square tubes are becoming higher and higher. Its zinc layer thickness is generally between Z80 and Z140. Its basic control points are as follows: 1、加工速度

1. Processing speed

對于普通鍍鋅產(chǎn)品而言，隨著帶鋼厚度降低而生產(chǎn)速度提升。但對于高表面 熱鍍鋅方管，生產(chǎn)速度提高后，由于其鋅層厚度較薄必然導(dǎo)致氣刀壓力加大，帶鋼鋅流紋缺陷則愈加嚴(yán)重。

For common galvanized products, the production speed increases with the reduction of strip thickness. However, for high surface galvanized square pipe, with the increase of production speed, the pressure of air knife will increase because of the thinner zinc layer, and the zinc rheological defect of strip steel will become more serious.

經(jīng)過生產(chǎn)分析認(rèn)為帶鋼厚度在0.7mm以上時生產(chǎn)速度與帶鋼厚度呈反比。0.6mm以下時應(yīng)適當(dāng)降低生產(chǎn)速度。

The production analysis shows that when the strip thickness is over 0.7mm, the production speed is inversely proportional to the strip thickness. The production speed should be reduced properly below 0.6mm.

2、鋅流紋問題

2. Zinc Ribbon Problem

鋅流紋問題是高表面 熱鍍鋅方管生產(chǎn)中的主要問題。鋅流紋問題產(chǎn)生的根本原因為鋅鍋中Al的產(chǎn)生。

Zinc rubbing is the main problem in the production of high-surface hot-dip galvanized square tubes. The root cause of zinc ripple problem is the production of Al in zinc pot.

1) 對酸軋聯(lián)機(jī)的要求。

1) Requirements for acid rolling on-line.

反射率60%以下，無論鍍鋅機(jī)組清洗段如何控制，Al含量均不能低于0.22%；反射率60 -80%，在增加鍍鋅機(jī)組清洗段電導(dǎo)率前提下，Al含量可以降低至0.16-0.22%。

Aluminum content can not be lower than 0.22% no matter how the cleaning section of galvanizing unit is controlled, and the reflectivity is 60-80%. Aluminum content can be reduced to 0.16-0.22% under the premise of increasing the conductivity of cleaning section of galvanizing unit.

2 ) 對鍍鋅機(jī)組清洗段要求。

2) Requirements for cleaning section of galvanizing unit.

需要鍍鋅機(jī)組清洗段增大清洗能力對殘留物進(jìn)行處理。一般電解段要求不低于60ms/cm,涮洗段不低于45ms/cm，即可對冷硬板表面洗凈。

It is necessary to increase the cleaning capacity of the cleaning section of galvanizing unit to deal with the residues. Normally, the electrolysis section should be no less than 60 ms/cm and the rinsing section should be no less than 45 ms/cm, so that the surface of the cold and hard plate can be washed.

3) 帶鋼入鋅鍋溫度

3) Temperature of strip into zinc pot

對于常規(guī)規(guī)格帶鋼人鋅鍋溫度控制在(465±5℃) 即可，但是對于薄規(guī)格、薄鋅層產(chǎn)品(0 0.4mm，Z80)，此溫度下帶鋼表面出現(xiàn)嚴(yán)重流紋和鋅層微裂紋。當(dāng)帶鋼溫度降低至440℃或提高至490℃時均可以將鋅裂紋基本消除。但是考慮到鋅流紋問題， 490℃最為合適 。

For conventional strip steel, the temperature of zinc pot can be controlled at (465 +5 C), but for thin strip steel and zinc layer products (0.4mm, Z80), serious ripple and zinc layer micro-cracks appear on the surface of strip steel at this temperature. Zinc cracks can be basically eliminated when the strip temperature is reduced to 440 or increased to 490 C. But considering the zinc rheological problem, 490 (?) C is the most suitable temperature.

3、光整機(jī)問題

3. Finishing Machine Problem

帶鋼在經(jīng)過光整機(jī)時，在軋制力作用下發(fā)生帶鋼長度、寬度方向上金屬流動。當(dāng)寬度方向上金屬流動受阻或者流動不一致，帶鋼出現(xiàn)暗紋。主要采?。?/p>

When the strip passes through the finishing machine, metal flow occurs in the direction of strip length and width under the action of rolling force. When the metal flow is blocked or inconsistent in the width direction, dark strip appears. Mainly adopt:

1) 加大光整機(jī)前后張力。

1) Increase the tension of the finishing machine.

2) 提高光整機(jī)防皺輥高度，并隨著帶鋼減薄而增加高度。

2) Increase the height of wrinkle-proof roll of finishing machine, and increase the height with the strip thinning.

4、其他

4, others

除上述幾點(diǎn)外。鍍鋅機(jī)組輥面清潔、輥系位置偏差、退火爐內(nèi)氫氣含量等常規(guī)項目也直接影響帶鋼表面狀態(tài)。因此建議生產(chǎn)前使用過渡卷提前按照設(shè)計工藝參數(shù)執(zhí)行，并利用油石打磨手段進(jìn)行生產(chǎn)評估。

In addition to the above points. Conventional items such as roll surface cleaning, roll system position deviation and hydrogen content in annealing furnace also directly affect strip surface condition. Therefore, it is suggested that the transition coil be used before production according to the design process parameters in advance, and the production evaluation should be carried out by means of oil stone grinding.