What to Consider When Choosing the Material of A Water Meter Body?
The earliest water meters were made of cast iron. Later on, as people have more diversified demands for flow measurement, there have been continuous development of body materials， which can help to increase metering performance, reliability, and also lower the production cost to some extent. There are plenty of materials commonly used in the water meter market currently, so how do we know we choose the right material for our water meter? and what should we consider when choosing the material of water meter body? We will introduce one by one in terms of different perspectives and separate them with advantages and disadvantages in the following text, including processing cost, material strength, castability, eco-friendliness, and so on.
Grey Cast Iron
Grey cast iron is one of the most common types of material used in water meters for all sizes nowadays.
- Good mechanical ability and castability: Grey cast iron can be molded into different shapes and sizes to satisfy different needs.
- Relatively low material cost: The material cost of cast iron is much lower than bronze and stainless steel.
- Good strength: High hardness of grey cast iron makes it workable in many industries.
- Weak in tensile strength: Gray iron is brittle, very easy to break when it bends or is being dragged. People should take it with care when install the water meter made of grey cast iron.
- Complex casting process methods: Casting shrinkage, draft angle, machining, surface finish, etc. should be taken into consideration in processing.
- Not eco-friendly: It’s corrosion and rust will cause secondary pollution, and does harm to people’s health. Must have surface anti-rust coating for protecting.
Therefore, if you have higher requirements in strength, castability and cost, but don’t care about tension and processing, gray iron will be an ideal option for your business.
Ductile Cast Iron
Also known as ductile iron, ductile cast iron is a new type of cast iron, because it has different spherical graphite structure than other types.
- Excellent in tensile strength: Ductile iron has twice the tensile strength of grey cast iron, so it is more reliable, durable and resilient than regular cast irons.
- Superior mach-inability and ca-stability: Same as grey iron.
- Good wear resistance: Ductile iron has higher abrasion resistance and it is typically used in engine system.
- Relatively higher cost: Ductile iron is more expensive than gray iron due to its more complicated chemical composition, which leads to difficult manufacture process and higher cost.
- Complex casting process methods: Even more complicated than the processing of gray iron.
- Not eco-friendly: It is susceptible to corrosion and rust, but ductile iron corrodes slower than regular cast iron. Must have surface anti-rust coating for protecting.
Therefore, if you have higher requirements in tensile strength and durability, but don’t mind high cost, we highly suggest you choosing ductile iron.
Stainless steel is a common material in our life and a powerful alloy that is used in many industries, and it is also popular in water meter manufacturing. Most of bodies are made of 304/316 stainless steel.
- Outstanding chemical stability: Stainless steel has excellent acid and alkali resistance, which makes it widely used in many chemical corrosive places. 316 has better corrosion resistant ability than 304 stainless steel.
- Environmental friendly: No secondary pollutants such as corrosive substances and exudes will be produced by stainless steel at high or low temperature.
- Good strength: Sames as other metals.
- Good weld-ability: People are developing welding stainless steel water meter body, which is much easier to process
- High production cost: Stainless steel casting parts are difficult to process. At present, there is no mass production capacity for this.
Therefore, if you pay more attention to the mechanical properties of the material and have to put the water meter in a highly corrosive environment, the best choice is stainless steel.
Plastic body is more used in small water meter sizes, because it doesn’t have good mechanical properties as metals.
- Much lower production cost than metals. Plastic bodies are easy to manufacture because it has less processing steps than metals’.
- Environmental friendly: Non-toxic, non-rusting and no secondary pollutants.
- Light weight.
- Week in mechanical strength: Plastic has poor rigidity and weakens over time, and it tends to change its physical properties at different temperature. For example, plastic is more easy to break in cold environment. Also, plastic is not suitable for big sizes of water meter.
However, many plastic suppliers are developing new plastic materials that can solve the problems. For example, Nylon has stronger mechanical strength and longer term creep than regular plastic materials. Therefore, the use of plastics as the material of the water meter body is the main direction of future development, which is also in line with the international energy conservation and emission reduction policy.
The copper and its alloys have antimicrobial properties. Apart from copper and zinc, copper alloys also contain iron, aluminum, lead, tin, manganese, silicon, nickel, etc, some of which will cause heavy metal pollution.
- Good mach-inability and ca-stability: The mach-inability will become better by adding lead, otherwise may cause crack.
- Simple casting process: The processing of brass meter body is easier than that of cast iron, though the forming steps are similar.
- Nice color and look: Brass can be used in decoration due to its beautiful gold-like color.
- High raw material cost: China is a country lacking in copper resources. The raw material cost of copper has soared in recent years in China. Besides, brass water meters are easy to be stolen for outdoor installation.
- Heavy metal pollution: Lead in Copper alloy will get into water and verdigris will do harm to people health. On the other hand, Melting of copper needs to consume a lot of energy, which is inconsistent with the policy of energy conservation and emission reduction.
As a result, copper-alloy water meters are beautiful but not cost-efficient.