Difference between nickel-plated and non-nickel-plated pipe fittings

Why is brass plated with nickel?

Friends who have done renovations or bought PPR water pipes will find that there are brass and silver pipes on the market . In this article, we will talk about the difference between these two pipe fittings.

First of all, we need to know what elements brass is composed of, why brass is plated with nickel, and what is the difference between non-nickel plated brass and nickel plated brass.

We usually see the pipe fittings, the brass used is not pure copper, but is composed of copper and zinc according to different proportions of the alloy, copper and zinc accounted for more than 97% of high purity copper zinc alloy, the purpose of adding zinc is to strengthen the hardness and strength of copper, and then add Fe, Pb, Al, Sn and other trace elements to improve the tensile resistance, corrosion resistance, anti-scale performance of the pipe fittings.

The reason why some brass pipe fittings on the market are nickel plated is to prevent brass oxidation, because the brass itself is poor in quality oxidation resistance, and the ratio of copper and zinc is low, so it is necessary to isolate the air by nickel plating to protect the normal use of pipe fittings. Nickel plating although can improve product performance, but nickel plating pipe fittings will cause secondary pollution to the water quality, you can imagine, in drinking water for a long time to soak a coin (coin is nickel material), because there is no ban on the use of nickel plating brass, so consider the cost, many water pipes still choose nickel plating method of production. The European Union Anti-corrosion Association stipulates that nickel-plated brass is not allowed to be used in drinking water systems, so non-nickel-plated brass is used in imported water pipes in the EU.

What is the difference between nickel plated and non-nickel plated brass composition?

Nickel-plated and non-nickel-plated brass is not only the proportion of nickel content is different, which Cu, Zn ratio difference is also very large, we through a customer provided test data to take a look (Figure 2), the left is Germany Emmann water pipe non-nickel-plated CW617 brass, the right is domestic nickel-plated brass.

What are the advantages of European standard CW617N brass?

The above mentioned water pipes imported by all EU countries are made of non-nickelized brass, and non-nickelized brass is also divided into many grades, of which CW617N(CuZn40Pb2) is one of the very few brass recognized by the German Gas and Water Association (DVGW), the specific standards can be seen (Figure 3).

Compared with other brass grades, the Cu content of European standard CW617N brass reaches 57%-59%, and the zinc content is 36%-46%, forming αβ biphase brass, β phase reduces the plastic strength of brass and increases the tensile strength, adding trace elements such as Fe, Sn and Ni that meet the requirements, the anti-oxidation, anti-corrosion and anti-scale, anti-pressure performance has been comprehensively improved.

Jian 505 Metal Products Co.,Ltd. pipe fittings using CW617N European standard brass to meet the standard of direct drinking water.