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钣金加工的设计中应谨慎选用镀锌层

2018-06-19 19:46:59 常州亿创钣金加工厂 阅读

钣金加工表面处理注意事项

钣金加工的工序表面处理对产品表面所起的装饰及防护作用被许多行业所认可。在钣金加工行业中,通常采用的表面处理方式有电镀、喷涂及其它的一些表处方式。

1、电镀分为:镀锌(彩锌,白锌,蓝锌,黑锌),镀镍,镀铬等; 主要是在料件表面形成一层防护层,起保护及装饰的作用;

2、喷涂分喷漆及喷粉两种,是将料件经过前处理以后,用喷枪,气体把涂料喷到钣金工件表面上,涂料在工件表面形成涂层.烘干后,起防护的作用; 

3、其它的表处方式:阳极氧化,铬酸盐,拉丝,喷砂,氧化等; 

注意事项! 

1. 所有电化学处理都应在零件状态下进行,因为处理过程中的化学溶液会被截留在组合件的缝隙之中而引起腐蚀;

2. 点焊的零件可进行化学处理,但不能进行电化学处理(包括电镀、阳极化);

3. 铝合金铸件不能进行硫酸阳极氧化处理; 

4. 细而长的管形(其长度大于2倍直径)零件一般不宜进行电化学处理,因为其内表面将没有膜层;(特殊情况可采取特别措施来满足要求) 

5. 有较深凹槽或细孔(一般指深度大于2倍直径或开口宽度,但优良的工艺可不受此限)的零件电镀后,其内表面将不能完全覆盖镀层;

6. 钢铁件喷涂前最好先进行磷化处理,以增加涂层的附着力;

7. 镀亮镍的钢件为提高其耐蚀性,可先镀铜或镀暗镍打底; 

8. 锌基合金一般采用电镀层作防护装饰,为提高其镀层的结合力,一般需先预镀铜或镍; 

9. 因多数有机气体对锌有腐蚀作用,故在钣金加工的设计中应谨慎选用镀锌层与有机材料接触或组装在同一密闭体内;

10. 对有铆接要求的电镀(氧化)件,其加工工序必须是先电镀(或氧化)、然后再铆接。

Attention to the surface treatment of sheet metal processing

Sheet metal processing surface treatment on the product surface decoration and protection are recognized by many industries. In sheet metal processing industry, surface treatment methods usually include electroplating, spraying and other surface treatments.

1, electroplating is divided into: galvanizing (color zinc, white zinc, blue zinc, black zinc), nickel plating, chrome plating and so on; mainly on the surface of the material to form a protective layer, play the role of protection and decoration;

2, spray paint spray paint and spray powder two kinds, is the material after the pretreatment, spray gun, gas spray coating on the surface of sheet metal workpiece, coating on the surface of the workpiece to form a coating. After drying, the protective effect;

3. Other ways of surface treatment: anodizing, chromate, wire drawing, sandblasting, oxidation, etc.

Matters needing attention!

1. all electrochemical treatment should be carried out under the condition of parts, because the chemical solution in the treatment process will be trapped in the gaps of the components and cause corrosion.

2. spot welding parts can be treated chemically, but they can not be treated by electrochemical treatment (including electroplating and anodizing).

3. aluminum alloy castings can not be treated by sulfuric acid anodization.

4. thin and long tube shaped (its length more than 2 times diameter) is generally unsuitable for electrochemical treatment because there will be no diaphragm on its inner surface; (special measures can be taken to meet the requirements).

5. the inner surface of the inner surface will not be fully covered with the deep groove or fine hole (which generally refers to the depth of 2 times the diameter or the opening width, but the fine process can not be subjected to this limit).

6. it is best to make phosphating before spraying steel parts, so as to increase the adhesion of the coating.

7. to improve the corrosion resistance of steel parts with bright nickel, copper or nickel plating is used.

8. zinc based alloy is usually used as protective coating for electroplating. To improve adhesion of coating, copper or nickel should be pre plated.

9. because most organic gases have a corrosive effect on zinc, it should be carefully chosen in the design of sheet metal processing to contact or assemble the organic materials in the same airtight body.

10. for electroplating (oxidation) parts with riveting requirements, the process must be galvanized (or oxidized) and then riveted.



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