热浸镀锌彩钢板的生产工艺主要包括:原板准备→镀前处理→热浸镀→镀后处理→成品检验等,通常按电镀前处理方法进行
热浸镀锌彩钢板工艺可分为两大类:湿法(单钢板热镀锌法)、离线退火法(单钢板热镀锌法)、车轮法(带钢连续热镀锌法),在线退火的Sendzimir法(保护气体法)采用改进的Sendzimir法、美国钢铁联合会(与日本川崎方法相同)、selas法和Sharon法。
锌可溶于酸和碱,因此被称为两性金属。锌的标准电极电位比钢的标准电极电位为负。当基体为钢铁时,当涂层被破坏或腐蚀形成铁锌原电池时,锌涂层属于阳极涂层,通过锌的牺牲溶解来保护钢。因此,钢表面的锌涂层不仅是一种机械保护,而且是一种电化学保护,防止基体腐蚀,即使锌涂层不完整。镀锌层的耐蚀性在很大程度上取决于钝化膜的耐蚀性。钝化锌层的耐蚀性可提高8~20倍。
热浸镀锌彩钢板常用的钢种有:普通商用卷材(CQ)、结构镀锌板(HSLA)、冲压镀锌板(DQ)、深冲热镀锌板(DDQ)、烘烤硬化热镀锌板(BH)、双相钢(DP)、TRIP钢(相变诱导塑性钢)等。The production process of hot-dip galvanizing plate mainly includes: raw plate preparation → pre plating treatment → hot dip coating → post plating treatment → finished product inspection, etc., which is usually carried out according to the pretreatment method of electroplating
Hot dip galvanizing process can be divided into two categories: wet process (single steel hot galvanizing method), off-line annealing method (single steel hot-dip galvanizing method), wheel method (continuous hot-dip galvanizing method for strip steel),
Sendzimir method for on-line annealing (shielding gas method) adopts improved Sendzimir method, American Iron and Steel Federation (same as Kawasaki method in Japan), selas method and Sharon method.
Zinc is soluble in acids and bases, so
it is called amphoteric metal. The standard electrode potential of zinc is negative than that of steel. When the substrate is steel, when the coating is damaged or corroded to form an iron zinc galvanic cell, the zinc coating belongs to the anode
coating, which protects the steel by sacrificial dissolution of zinc. Therefore, the zinc coating on the steel surface is not only a mechanical protection, but also an electrochemical protection to prevent corrosion of the substrate, even if the zinc
coating is incomplete. The corrosion resistance of zinc coating largely depends on the corrosion resistance of passive film. The corrosion resistance of passivated zinc coating can be increased by 8-20 times.
There are two kinds of zinc plating
bath: cyanide plating solution and non cyanide plating solution. Cyanide plating bath is divided into micro cyanide, low cyanide, medium cyanide and high cyanide. Cyanide free plating bath includes alkaline zincate bath, ammonium salt plating bath,
sulfate plating bath and ammonia free chloride plating bath. Cyaniding zinc plating solution has good bath performance and bright and clean coating, which has been used for a long time in production. However, due to its high toxicity and serious environmental
pollution, low cyanide, micro cyanide and non cyanide zinc plating solutions have been used in recent years.
The mechanical properties of hot rolled steel plate are much lower than those of cold working and forging, but they have better toughness
and ductility. The strength of hot-rolled plate is relatively low, the surface quality (oxidation finish is low), but the plasticity is good. Generally, it is medium thick plate. Cold rolled sheet: high strength, high hardness, high surface finish,
generally thin steel plate, can be used as stamping plate. Cold rolled steel sheet has low toughness due to work hardening to a certain extent, but it can obtain better yield ratio, which can be used for cold bending of spring sheet and other parts.
At the same time, because the yield point is close to the tensile strength, the danger can not be foreseen in the process of use, and accidents are prone to occur when the load exceeds the allowable load.
Hot dip galvanized sheet is mainly used
in construction, home appliances, automobile, machinery, electronics, light industry and other industries.
The commonly used steel grades of hot dip galvanized sheet are: common commercial coil (CQ), structural galvanized sheet (HSLA), stamping
galvanized sheet (DQ), deep drawing hot dip galvanized sheet (DDQ), bake hardening hot dip galvanized sheet (BH), dual phase steel (DP), TRIP steel (phase transformation induced plasticity steel), etc.