Water meter is the key equipment for flow measurement, the choice of its shell material is very important. Early water meters mostly used cast iron material, with the increasingly diversified flow measurement needs and the continuous progress of material technology, water meter materials in improving the measurement performance and reliability, but also committed to reducing production costs. In this context, how to select the right material for the water meter becomes a key issue. The following will be discussed from the processing cost, material strength, reliability, environmental protection and other aspects, and a detailed analysis of the advantages and disadvantages of various materials.
1. Gray cast iron
Gray cast iron is one of the commonly used materials in water meters of various sizes.
Advantages:
1. With good mechanical properties and castability, it can be shaped into different shapes and sizes according to different needs, and has strong adaptability.
2. The material cost is relatively low, compared with bronze and stainless steel, its cost advantage is significant.
3. Good strength performance, high hardness, in many industries are used.
Cons:
1. The tensile strength is weak, the texture is brittle, it is easy to break when bending or dragging, and the installation process needs to be extra careful.
2. The casting process is complex, involving many problems such as casting shrinkage, tension, processing and surface finish, etc., which need to be considered comprehensively in the treatment process.
3. Poor environmental protection, corrosion and rust will cause secondary pollution, posing a threat to human health, so it is necessary to be equipped with surface anti-rust coating to protect.
In summary, if the enterprise has specific requirements for strength, quality and cost, and the requirements for tensile strength and processing technology are not high, gray cast iron is an ideal choice.
2.Ductile iron
Ductile iron is a new type of cast iron, and its ductile structure is different from other types of cast iron.
Advantages:
1. Excellent tensile strength, about twice that of gray cast iron, better reliability, durability and elasticity.
2. Excellent mechanical properties and stability, similar to gray cast iron.
3. Good wear resistance, often used in engine systems and other areas with high wear resistance requirements.
Cons:
1. The cost is relatively high, because of its complex chemical composition, difficult manufacturing process, and higher price than gray cast iron.
2. The casting process is equally complex, even more difficult than the processing of gray cast iron.
3. Lack of environmental protection, vulnerable to corrosion and rust, although the corrosion rate is slower than ordinary cast iron, but still need to be protected by surface anti-rust coating.
Therefore, if there is a high expectation of tensile strength and durability, and is not too sensitive to cost factors, ductile iron is a recommended material.
3.Stainless steel
As a powerful alloy widely used in daily life and many industries, stainless steel is also popular in the field of water meter manufacturing, and most water meter mechanisms are made of 304/316 stainless steel.
Advantages:
1. Excellent chemical stability, good acid and alkali resistance, especially 316 stainless steel corrosion resistance is more prominent, suitable for a variety of chemical corrosion environment.
2. Good environmental performance, in the high and low temperature environment will not produce corrosive substances and emissions and other secondary pollutants.
3. Good strength performance, comparable to other metals.
4. Good welding performance, easy to weld the water meter body, easy to operate.
Cons:
1. The production cost is high, the processing of stainless steel casting parts is difficult, and the current lack of large-scale production capacity.
In summary, if the mechanical properties of the material are more concerned, and the water meter needs to be used in a high-corrosion environment, stainless steel is undoubtedly the best choice.
4. Plastics
Plastic is more common in small water meter size applications, although its mechanical properties are not as good as metal materials.
Advantages:
1. The production cost is much lower than that of metal materials, the manufacturing process is simple and the processing steps are less than that of metal materials.
2. Good environmental performance, non-toxic and harmless, no secondary pollution.
3. Light weight.
Cons:
1. Limited mechanical strength, poor stiffness, easy to decay with time, and physical properties will change at different temperatures, such as more likely to break in cold environments, not suitable for large size water meters.
However, at present, many plastic suppliers are actively developing new plastic materials to solve such problems. Nylon materials, for example, have significantly higher mechanical strength and longer creep time than ordinary plastics. Therefore, plastic as a water meter housing material is the main trend of future development, and also conforms to the international energy conservation and emission reduction policy guidance.
5. Brass
Copper and its alloys have antibacterial properties. As a copper alloy, brass contains iron, aluminum, lead, tin, manganese, silicon, nickel and other elements in addition to copper and zinc components, some of which may cause heavy metal pollution.
Advantages:
1. The machining performance and CAA stability are good, adding lead can further optimize the machining performance and reduce the risk of cracks.
2. The casting process is relatively simple, and the processing difficulty of brass instrument body is lower than that of cast iron, although the forming steps are similar.
3. Beautiful appearance, golden color, can be used for decorative purposes.
Cons:
1. The cost of raw materials is high, China’s copper resources are scarce, and the cost of copper raw materials has continued to rise in recent years. In addition, brass water meters installed outdoors are vulnerable to theft.
2. There is a risk of heavy metal pollution, and the lead in the copper alloy may dissolve into the water, breeding green algae and endangering human health. At the same time, the copper melting process has a high energy consumption, which is contrary to the policy of energy conservation and emission reduction.
In summary, although the brass alloy water meter looks beautiful, it is low cost performance.