您好,欢迎来到济南新雄经贸有限公司官方网站!

400-0616-756

行业动态

Industrydynamics

产品中心
当前位置: 首页-新闻中心-行业动态-镀锌钢管的镀锌要求有哪些?

镀锌钢管的镀锌要求有哪些?

来源:http://www.jnxxjm.com

【 发布于:2018-11-05 16:30:50 】


镀锌钢管锌镀层的外观呈青白色,标准电极电位为-0.76V,易溶于酸,溶于碱,是典型的两性金属。锌在干燥空气中不发生变化,锌腐蚀的临界湿度大于百分之七十,因此在潮湿大气中能与二氧化碳和氧作用生成一层主要由碱式碳酸锌组成的薄膜,这层膜有缓蚀作用,锌与硫化氢等含硫化物起反应生成硫化锌﹔锌易受氯离子浸蚀,故在海水中不稳定。

The appearance of zinc coating on galvanized steel pipes is blue-white. The standard electrode potential is -0.76V. It is soluble in acid and alkali. It is a typical amphoteric metal. Zinc does not change in dry air. The critical humidity of zinc corrosion is more than 70%. Therefore, in humid atmosphere, zinc can react with carbon dioxide and oxygen to form a film consisting mainly of basic zinc carbonate, which can inhibit corrosion. Zinc reacts with sulfides such as hydrogen sulfide to form zinc sulfide. Zinc is vulnerable to chloride ions. Therefore, it is unstable in seawater.

镀锌钢管的锌在密闭或通风不良,空气潮湿的条件下,与非金属材料的挥发物(低分子羧酸,醛,酚,氨等)接触时,锌易遭腐蚀,生成白色疏松的腐蚀产物,俗称”白霜”。锌在高温,高湿,密闭条件下,与胶木,油漆,木材释放的挥发物接触,锌有生长细丝状单晶的倾向,俗称”长毛” 。

20171219904795.jpg

Zinc of galvanized steel pipe is easy to be corroded when it contacts with volatiles of non-metallic materials (low molecular carboxylic acid, aldehyde, phenol, ammonia, etc.) under the conditions of airtight or bad ventilation and humid air, resulting in white loose corrosion products, commonly known as "white frost". Zinc has a tendency to grow filamentous single crystals, commonly known as "long hairs", in contact with volatiles released from bakelite, paint and wood under high temperature, high humidity and airtight conditions.

锌的标准电位比铁负,对钢铁而言是阳极性镀层,可提供电化学保护。在工业大气,农村大气和海洋性大气中使用的钢铁制品均可选择锌作保护层,其防护寿命与锌层厚度成正比关系。凡属有工业废气污染的大气中,镀锌钢管锌镀层的耐蚀优于镉镀层,在海上或海水中则相反。

The standard potential of zinc is higher than that of iron, which is anodic coating for iron and steel. It can provide chemical protection for power supply. Zinc can be used as protective layer for steel products in industrial atmosphere, rural atmosphere and marine atmosphere. Its protective life is proportional to the thickness of zinc layer. In the air polluted by industrial exhaust gas, the corrosion resistance of zinc coatings on galvanized steel pipes is better than that of cadmium coatings, while in the sea or sea water, the opposite is true.

锌镀层经铬酸盐钝化之后,耐蚀性可增加6--8倍。所以镀锌钝化处理是重要的步骤。在钝化膜上进行有机染色,可作低文件产品的防护装饰镀层。

The corrosion resistance of zinc coating can be increased by 6--8 times after chromate passivation. Therefore, zinc passivation is an important step. Organic dyeing on passivation film can be used as protective coating for low paper products.



上一篇:给广大网友选择镀锌管的建议!
下一篇:不锈钢无缝管热处理时怎么清理表面?