The faucet is the most widely used and the most widely […]
The faucet is the most widely used and the most widely used in the water appliances for washing and washing. With the improvement of people's living standards, the continuous improvement of housing conditions and living facilities, the demand for high-end nozzles is increasing, and the quality of the surface coating of nozzles is also higher. For the quality of nozzle plating, the author checked A lot of relevant information, and acid salt spray test on some products. Now will improve the plating quality of the faucet, and talk about the following issues.
1 selection of materials
The nozzle plating quality depends not only on the plating process, but also on the nozzle base material, casting process, and pre-plating treatment. The water valve body is the main part of the faucet. The material is cast brass. The most popular type is Cu40ＺnPb2. The average wall thickness of the casting is 3mm. The valve body, handle and bonnet of a good faucet are all made of brass. After casting, processing, surface grinding and polishing, nickel plating, decorative chromium or chromium-nickel alloy, if such products are processed before plating, plating, plating The process is well processed and generally relatively corrosion resistant. In order to enhance the product's corrosion resistance and product grade, a multilayer nickel plating process is also used. However, in order to save production costs, some companies have mixed a large amount of scrap copper into the cast brass, causing the cast brass to contain a large amount of impurities. After the acid salt spray test, pitting and pitting occurred. Some manufacturers even use cast iron and zinc alloys that have been eliminated as raw materials.Because cast iron is rusty and zinc alloys are not resistant to corrosion, water nozzles made from these materials are prone to rust spots. After 2h acid salt spray test, the valve body A large number of defects such as rust spots and pits appeared. Other manufacturers use brass as the valve body, while the handle and bonnet are made of inferior materials such as cast iron and plastic. After 24h acid salt spray test, the valve body does not produce corrosion, and the handle and valve The cover showed severe corrosion, which caused the product to fail and reduced the grade of the product.
2 casting process
The water nozzle valve body is the main component of the water nozzle. Its production method generally uses sand casting and metal casting. Due to the high quality of the surface of the water nozzle, the outer surface of the casting before electroplating must not have any visible pores, cracks, looseness and inclusions; the metal nozzle casting has a dense body structure, good surface quality and high yield, and It is also possible to avoid environmental pollution caused by sand casting, so most manufacturers currently use metal casting technology. However, using a metal mold casting nozzle, the outer surface is formed by a metal mold, and the inner cavity is formed by a coated sand core.When the copper liquid is poured into the metal mold cavity, the external surface cooling rate is faster and the casting structure is dense; The cavity is surrounded by a sand core, the cooling rate is slow, and it is easy to produce shrinkage defects. Although some manufacturers use cast brass with good material, after 24h acid salt spray test, the valve body still has light loss and rust spots. The reason is that when the nozzle body is cast, the result of the casting process is not handled well. Therefore, only by strengthening the design of the casting mold, the melting and pouring of the alloy, the control of the casting process and the cleaning of the falling sand, can the qualified nozzle body casting be cast.
3. Polishing and cleaning before nozzle plating qualified castings need to undergo mechanical processing, grinding and polishing before plating.
Machining and grinding are used to shape the product. Grinding and polishing mainly level the surface of the product to reduce the roughness of the casting. At the same time, it can also eliminate minor defects such as trachoma and burrs caused by casting. As the appearance quality of the water nozzle is relatively high, the coating on the outer surface of the water nozzle should be well combined, the structure should be fine, smooth and uniform, and the color and luster should be bright. The polished outer surface should be bright, and there should be no appearance defects such as bubbles, scorching, detachment, scratches, etc. . Polishing quality is the key factor to ensure the quality of electroplating, improve the surface brightness and eliminate defects. Taps are decorative products. It is very sensitive to inclusions and inclusions. Even very small impurities may cause defects such as burrs, pits or pinholes on the electroplated surface, and even scorching, blistering and peeling of the coating. For example, after the 24h acid salt spray test, light loss and rust spots will appear, and even bubbling and full corrosion, etc., so the pretreatment is very important. The sand and carbonized resin in the inner cavity after casting, the grease, copper filings and copper powder left after machining, and the polishing paste after polishing must be cleaned to ensure the quality of electroplating. The presence of contamination is a major factor in the occurrence of burrs and pits in electroplating.
4.Control of plating process
The surface of the nozzle is mainly nickel-chrome. The electroplating nickel-chromium process has a history of many years.The electroplating process is very mature, the chemical raw materials and additives are high in purity, and there are few impurities; and the electroplating equipment is advanced. As long as the process management is strict during the electroplating process, the bath fluid, rinse water, equipment and production are maintained. The environment is clean and generally there are fewer problems with plating quality. The non-corrosion resistance found in the inspection is mainly because some manufacturers have reduced the plating time, reduced the plating time, and the coating is thin, which cannot completely compensate the pores of the coating. The corrosive solution corrodes to the substrate through the pores, and a large number of rust spots appear.
1) The valve body, handle and bonnet of the faucet must be made of better quality cast brass or copper alloy, and cast off easily rusty cast iron, non-corrosive zinc alloy and other materials;
2) Adopt metal casting nozzle body and pay attention to the casting process;
3) Grinding and polishing should be thorough, and do pre-plating treatment;
4) Strictly implement the electroplating nickel-chromium process specifications, strengthen process management, and ensure coating thickness.
Ningbo Afa Kitchen & Bath Co , Ltd . is a leading global manufacturer of stainless steel faucets . AFA insists: first consider quality, then cost. Quality first, then output. Over the years, AFA has relied on superior quality, innovation and market acumen to continuously lead the innovation revolution of kitchen and bathroom products. To view the quality and variety of stainless steel faucet products, please visit: http://www.afastainlesskb.com