钢基板中各元素对热镀锌彩钢卷的影响
1碳的影响
泰州热镀锌彩钢卷生产厂家钢中碳含量越高，铁锌反应越强，铁的损失越大，钢基体的反应越强，即铁锌合金层越厚，锌层的附着力越差。因此，碳含量小于0.15%的低碳钢板适用于热镀锌。
2硅的影响
泰州热镀锌彩钢卷生产厂家钢基体中硅含量高，给热镀锌带来困难。一般认为硅含量高的镇静钢不能用于热浸镀锌，因此长期以来，硅含量小于0.07%的沸腾钢多用于热镀锌板
泰州热镀锌彩钢卷生产厂家实践证明，钢基体中硅含量高，会导致锌镀层铁锌合金层ξ相严重增厚，形成灰色镀层，使锌镀层的附着力变差。
人们已经认识到钢基体中高硅含量对热镀锌的有害影响。然而，其作用原理相当复杂。然而，人们普遍认为，钢板中的硅对热镀锌的影响主要取决于二氧化硅而不是游离硅。
泰州热镀锌彩钢卷生产厂家主要原因是硅的原子体积小，而硅对氧的亲和力大，在退火炉中很难被氢还原。钢板在钟罩式炉中加热或再结晶时，硅表面会富集，并会发生以下化学反应：
Si+O2=SiO2
Si+2FeO=SiO2+2Fe
这样，不仅在钢板表面，而且在钢板内部形成一层氧化硅薄膜。
结果表明，灰层中脆性ξ相特别发育，导致Fe-Zn合金层急剧长大，镀层结合力降低。由此可见，钢板中的二氧化硅是影响热镀锌的主要因素。
三。钛的作用
钛是低合金高强度热镀锌板生产中的主要添加元素，对镀锌过程影响不大，但对钢板的力学性能有一定影响。由于钛与碳、氮有很强的亲和力，它可以在钢中形成tic和tin的状态。由于碳和氮是引起钢时效的主要元素，所以含钛的钢会固氮固碳，对钢的抗时效起着重要作用。
4锰、磷、硫
一般来说，低碳钢中锰、磷含量较少。实践证明，钢中锰、硫含量对镀锌层组织影响不大。然而，钢中的磷对热镀锌有显著的不良影响。当磷含量为0.15%左右时，ξ相和δ1相由于η相转变较薄而生长迅速。当η相转变很薄甚至完全不含η相时，涂层会出现暗斑并使涂层粘附
5热浸镀锌
必须控制锌浴温度、镀锌时间和工件引出锌液的速度。萃取速度一般为1.5m/min，若温度过低，锌液流动性差，镀层厚薄不均，易产生流挂，外观质量差；温度高时，锌液易与工件分离，可减少流挂和起皱，强度大附着力强，镀层薄，外观好，生产效率高；但当温度过高时，工件和锌锅的铁损严重，产生大量的锌渣，影响锌镀层的质量，容易受影响色差使表面颜色难看，而锌消费高。
锌层厚度取决于锌液温度、浸锌时间、钢材材质和锌液成分。
为防止工件高温变形，减少铁损造成的锌渣，采用450～470℃保温0.5～1.5min，部分工厂对大型工件和铸铁件采用较高温度，但避开了铁耗峰值的温度范围。建议在锌液中加入具有除铁、降低共晶温度的合金，并将镀锌温度降至435～445℃。
1. The impact of carbon
The higher the carbon content in the steel, the stronger the iron zinc reaction, the greater the loss of iron, the stronger the reaction of steel base, that is, the thicker the iron zinc alloy layer becomes, the worse the adhesion of zinc coating. Therefore,
low carbon steel sheet with carbon content less than 0.15% is suitable for hot galvanizing.
2. Influence of silicon
The high silicon content in steel substrate will bring difficulties to hot dip galvanizing. It is generally considered that
killed steel with high silicon content can not be used for hot dip galvanizing, so boiling steel with silicon content less than 0.07% is mostly used as hot-dip galvanizing plate for a long time
It has been proved by experience that the high silicon
content in the steel base will cause the severe thickening of the ξ phase in the iron zinc alloy layer of the zinc coating, forming a gray coating, and making the adhesion of the zinc coating worse.
It has been recognized that the harmful effect
of high silicon content in steel substrate on hot-dip galvanizing has been recognized. However, the principle of its action is quite complicated. However, it is generally believed that the effect of silicon in steel plate on hot-dip galvanizing mainly
depends on silicon dioxide rather than free silicon.
The main reason is that the atomic volume of silicon is small and silicon has a large affinity for oxygen, so it is difficult to be reduced by hydrogen in annealing furnace. When steel plate is
heated or recrystallized in bell type furnace, silicon surface can be enriched and the following chemical reactions can occur:
Si + O2 = SiO2
Si +2FeO = SiO2 + 2Fe
In this way, a layer of SiO2 oxide film will be formed not only on the
surface of the steel plate, but also in the interior of the steel plate.
It is found that the brittle ξ phase in the gray coating is especially developed, which leads to the sharp growth of the Fe Zn alloy layer and the decrease of the adhesion
of the coating. It can be seen that SiO2 in steel sheet is the main factor affecting hot dip galvanizing.
3. Effect of titanium
Titanium is the main additive element in the production of low alloy high strength hot-dip galvanized sheet, which
has little effect on the galvanizing process, but has a certain impact on the mechanical properties of the steel plate. Because titanium has a large affinity with carbon and nitrogen, it can become the state of tic and tin in steel. Because carbon and
nitrogen are the main elements that cause steel aging, so the steel containing titanium will fix nitrogen and carbon, which plays an important role in the anti-aging of steel.
4. Manganese, phosphorus and sulfur
Generally, it contains less
manganese and phosphorus in low carbon steel. Practice has proved that the content of manganese and sulfur in steel has little effect on the structure of zinc coating. However, phosphorus in steel has a significant bad effect on hot dip galvanizing. When
the phosphorus content is about 0.15%, the growth of ξ phase and δ 1 phase is very fast because of the thin η phase transition. Where the η phase transformation is thin or even completely free of η phase, the coating will appear dull spots and make the
coating adhere
5. Hot dip galvanizing
It is necessary to control the temperature of the zinc bath, the time of galvanizing and the speed of the work piece leading out of the liquid zinc. The extraction speed is generally 1.5 m / min. If the
temperature is too low, the fluidity of liquid zinc is poor, and the coating is thick and uneven, it is easy to produce sagging and poor appearance quality; when the temperature is high, the liquid zinc is easy to separate from the workpiece, which can
reduce sagging and wrinkling, with strong adhesion, thin coating, good appearance and high production efficiency; however, when the temperature is too high, the iron loss of the workpiece and zinc pot is serious, resulting in a large number of zinc slag,
which affects the quality of zinc coating and is easy to be affected The color difference makes the surface color unsightly and the zinc consumption is high.
The thickness of zinc layer depends on the temperature of liquid zinc, the time of zinc
dipping, the material of steel and the composition of liquid zinc.
In order to prevent high temperature deformation of workpiece and reduce zinc slag caused by iron loss, 450 ～ 470 ℃ is adopted for 0.5 ～ 1.5min. Some factories adopt higher temperature
for large workpieces and iron castings, but avoid the temperature range of peak iron loss. However, we suggest that the alloy with the function of removing iron and reducing eutectic temperature should be added into the liquid zinc, and the zinc plating
temperature should be reduced to 435-445 ℃.
