Valves - Choosing between Ductile Iron and Cast Iron

13 May.,2024

 

Valves - Choosing between Ductile Iron and Cast Iron

Customers from a wide range of industries require a variety of valves to meet their demanding processes. Valves are available in a large variety of materials for any conceivable application. Some of these materials are PVC, carbon steel, stainless steel, cast iron and ductile iron. In this article, we will focus on two of these materials: ductile iron and cast iron. The "ductile vs. cast iron valve" debate has been going on for decades, because not everyone knows the difference.

Contact us to discuss your requirements of 200mm ductile iron pipe. Our experienced sales team can help you identify the options that best suit your needs.

Fortunately, comparing valves made of ductile iron and cast iron is simple, as there are only a few major differences between these materials. We will outline the characteristics of both materials and then present the advantages and disadvantages of each. By the end of this blog post, you'll be an iron expert!

 

Popular DIN 3352 F4 Ductile Iron Resilient Seat Gate Valve Made in China

 

Cast Iron Valve Specifications

Cast iron (also known as gray iron) is a metal that has been used for centuries. It is an alloy made of 96-98% iron, 2%-4% carbon and a small amount of silicone. It has impressive temperature tolerance, with some cast irons capable of handling temperatures in excess of 2100F (1150C). In terms of pressure, the strength of cast iron depends on its pressure rating. The two most common are Grade 125 and Grade 250. At less extreme temperatures, Class 125 cast iron flanges are rated between 150 and 200 psi. Class 250 cast iron is tougher and is rated from 300 to 500 psi. these pressures may vary depending on the end type.

Cast iron is strong and usually does not break, even after strong vibration. The main disadvantage of cast iron valves is that they are not very ductile. Almost any bending will cause cast iron to crack and become useless. One of the major advantages of cast iron is that it is not very expensive. As far as metals go, cast iron is usually the most economical choice, which makes it a reliable choice for people on a budget.

 

Ductile Valve Specifications

The second material we are looking at is ductile iron. Ductile iron is a more modern iron alloy made of spheroidal graphite. This gives the material excellent ductility, so it won't necessarily break when bent. Temperature limits are slightly lower than cast iron, but still quite high at 1350F (730C). In terms of pressure, ductile iron valves also use pressure grades: 150 and 300. 150 grade ductile iron maintains a seal of up to 250 psi at standard outdoor temperatures. 300 grade can withstand pressures up to 640 psi.

Ductile iron has excellent corrosion resistance, tensile strength and yield strength. Unlike cast iron, ductile iron does not fracture when bent, making it more suitable for demanding applications. Ductile iron is a strong and reliable material for pipes, fittings and valves. One drawback is the price. Because of its more complex chemical composition, ductile iron is usually more expensive than cast iron. However, if your application requires a tougher material, you may need to spend a little more.

 

Popular DIN 3352 F4 Ductile Iron Resilient Seat Gate Valve Made in China

 

Ductile Iron Valves vs. Cast Iron Valves

Now that we have looked at these two options separately, we will compare and contrast ductile iron and cast iron valves. Hopefully this will help you decide which is best for you! We'll compare the price, durability and ease of installation of these materials so you know the most important details.

 

Price

● Cast Iron: Compared to ductile iron valves, cast iron valves will save you a lot of money due to their simpler manufacturing process. If you don't need the additional benefits that ductile iron offers, cast iron is the smart move.

● Ductile Iron: Ductile iron is the more expensive option, but for good reason. In many cases, it offers significantly better properties than cast iron.

 

Durability

● Cast Iron: Cast iron is a strong material that can withstand higher pressures than any plastic. However, when the pressure rating of a cast iron valve or pipe is exceeded, it may bend and crack. Cast iron has almost zero ductility, which means it is rigid and will break if bent. Cast iron will also rust over time, so regular maintenance is necessary to keep the valve free from corrosion.

● Ductile Iron: Ductile iron also has impressive structural integrity. It can handle high pressures and temperatures without retreating. Due to its ductility, this material is also less likely to crack when bent. Ductile iron will also rust over time, but not as easily as cast iron.

 

Easy to install

● Cast Iron: This material offers the user many options when it comes to installation. Cast iron valves are typically bolted using flanges. Welding is difficult, but not impossible. Our cast iron valves are available with flanged ends, as this is an excellent method for high or low pressure applications.

● Ductile Iron: Ductile iron offers the user many of the same installation options due to its similarity in construction to cast iron. Welding is not recommended, but bolted connections using flanges are still the best option for most applications.

 

There you have it! Now you know it's not a matter of "tough vs. cast iron valves" or anything like that. One isn't always better than the other. It all depends on what you are using it for!

 

 

Types Of Pipe Materials: Must-Know Before Buying

Pipes are an important component in building construction. There are various types of pipe materials available in the market. Selection of pipe materials for your house plumbing system can be a tedious task, but not anymore. Gharpedia brings to you a guide for different types of pipe materials, their advantages and disadvantages, and their popular manufacturers. After going through this blog, you will have clarity on this topic, for sure.

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Before we dive into the different pipe material types, let’s have a look at the factors to be considered while selecting pipe materials.

Factors to Consider while Selecting Pipe Materials for Water Supply/House Plumbing

The selection of pipe materials for water supply or for house plumbing system depends on the following factors:

  • Internal pressure and external loads to which the pipe is subjected.
  • Capital cost and maintenance cost.
  • Availability of funds.
  • Carrying capacity of the pipe.
  • Quality of flow to be carried.
  • Expected life of the pipe.
  • Ease of repair and replacement.

Consider the above-mentioned factors carefully while selecting water pipe materials.

Types of Pipe Materials Commonly used

The different pipe material types used in house plumbing system are as follows:

01. Cast Iron (C.I.) Pipes

Cast iron pipes can rust, but they can be protected using rust prevention products. These pipes are used as rainwater pipes and waste pipes. They are also used for storm drains and sewage in high-rise buildings. One more use of this pipe is for garbage disposal because it is highly resistant to abrasions and grinding that may be caused by the food and other particles passing through it on a daily basis. Cast iron pipes are used in house drainage systems because they don’t produce echoing sounds when water moves through them. The pipes are manufactured in sizes from 17 to 609 mm.

Let’s now focus on the advantages of cast iron pipes and disadvantages of cast iron pipes:

Advantages of Cast Iron Pipes

  • Cast iron pipes can be made corrosion resistant by using rust prevention products.
  • Joining cast iron pipes is easier.
  • Cast iron pipes have high durability. Though they may not last for a century, with proper maintenance, they can last several decades.
  • Service connection in cast iron pipes can be easily made.

Disadvantages of Cast Iron Pipes

  • These piping materials are heavier and hence uneconomical when their diameter is more than 1.2 meter.
  • There are possibilities of breakages during transportation.

We have a detailed article on cast iron pipes, for further information:

Cast Iron Pipes Manufacturers

The following are the popular cast iron manufacturers:

  • Jayswal Neco Industries Ltd.
  • Jupiter Metal Industries (Jal.)
  • Kapilansh Dhatu Udyog (P) Ltd.

02. Steel Pipes

Stainless steel is commonly used in drainage parts or components because it is easily cleanable and sterile, making it an excellent choice for places that demand strict hygienic conditions. Aesthetic appearance, corrosion resistance, ease of fabrication, fire and heat resistance, hygiene, strength-to-weight, and impact resistance are just a few advantages of using stainless steel pipes. They are used in your shower, tap and the rest of the house, especially in exposed pipes because they can withstand the onslaught of external factors such as rain, heat and rust. The nominal diameter of steel pipes ranges from 21.3 to 1200 mm. There are three types of steel pipes available in the market, they are:

  • Electrically welded steel pipes
  • Seamless pipes
  • Spirally welded pipes

Advantages of Steel Pipes

  • Steel pipes are easy to work with. They are easy to handle and transport.
  • Steel is strong in tension; even large diameter pipes can be made with thin shells.
  • It can withstand high internal pressure.

Disadvantages of Steel Pipes

  • The life of a steel pipe is generally half that of a cast iron pipe.

Steel Pipes Manufacturer

The popular steel pipe manufacturers are:

  • Surya Roshni Ltd.
  • Tata Steel Ltd.
  • APL Apollo Tubes Ltd. 
  • JSW Steel Ltd.

03. Concrete Pipes

Concrete pipes are widely used in construction and require no introduction. It is the most prevalently used drainage pipe due to its availability locally, low cost, strength, and durability. Another reason these pipes are widely used is their eco-friendliness and non-flammability, as opposed to plastic pipes. Cement concrete pipes may be either reinforced or plain. Plain cement concrete pipes are manufactured in small sizes, while they are reinforced with steel for large diameter pipes. The cement concrete pipes may be either cast-in-situ or precast. This type of piping material serves as a conduit material for sanitary sewers, storm drains and culverts, which carry water underground. The nominal diameter of concrete pipes ranges from 90 to 2000 mm.

Advantages of Concrete Pipes

  • Precast concrete pipes offer flexibility as they can be built as per required specifications.
  • This plumbing pipe material, once installed, demands little maintenance.
  • Unlike iron pipes, there is no corrosion of concrete pipes.
  • For small works, expansion joints are not normally required.

Disadvantages of Concrete Pipes

  • It is difficult to repair concrete pipes.
  • Due to heavy weight and bulk, they are difficult to transport and need to be handled carefully on-site.
  • After a certain period of time, concrete pipes tend to leak due to porosity and shrinkage cracks.
  • As they are manufactured in small lengths, the number of joints required by this type of piping material increases.

Concrete Pipes Manufacturers

The following are popular concrete pipes manufacturers:

  • Aadit concrete products pvt. ltd.
  • Ameya concretech pvt.ltd.
  • Garima Cement Pipe Industries LLP

04. Asbestos Cement (A.C.) Pipes

Asbestos Cement pipes (AC pipes) are manufactured from asbestos fibres and cement. The use of asbestos fibres reduces the weight of the pipes while maintaining adequate strength. Since AC pipes do not contain reinforcement steel, they are resistant to hydrogen sulphide corrosion and aggressive soils. The smooth walls of the pipe provide low friction factors, resulting in low operating costs. Asbestos cement pipes are generally used in vent pipes, soil pipes and rainwater pipe. Asbestos cement pipes are available in a variety of widths and lengths. They are not recommended for underground situations. The nominal diameter of asbestos cement pipes ranges from 600 mm to 1000 mm.

Advantages of Asbestos Cement Pipes

  • Asbestos cement pipe has smooth internal surface, so the friction losses are reduced.
  • They are light, so they can be easily transported and handled.
  • Asbestos cement pipes can be easily jointed, fitted or cut.
  • They are anti-corrosive.

Disadvantages of Asbestos Cement Pipes

  • One of the major disadvantages of asbestos cement pipes, is that they are costly.
  • This plumbing pipe material has less durability.
  • They are brittle and hence can easily break.

Asbestos Cement Pipe Manufacturers

The popular asbestos cement pipe manufacturers are:

  • ARL infratech Ltd.
  • Mahalakshmi industries
  • G.B asbestos pipes

05. Plastic Pipes

Plastic pipes are the most common drainage pipes nowadays. This is primarily due to the fact that it is cheaper when compared to other types of pipe materials. In the house drainage system, the soil pipes and waste pipes are generally plastic pipes. This hot water pipe material is strong enough to tolerate any pressure. It only takes some glue to join two parts together, thereby saving time on welding or soldering. From the environmental point of view, plastic pipes are not good. Not only is it non-recyclable, but its production involves a high degree of pollutants too. Plastic pipes are affected by exposure to ultraviolet radiation and hence may become brittle after some years. Hence, it is recommended to protect the plastic drainage pipes from sunlight, by wrapping the pipe and fittings with an opaque material or painting it. Nominal inside diameter of plastic pipes available are 50, 65, 75, 90, 100, 125 and 150 mm. Plastic pipes are also used as hot water pipe material. Following types of plastic pipes are generally available in the market.

(a) Low density polyethylene (LDPE) pipes

(b) High density polyethylene (HDPE) pipes

(c) Unplasticised-polyvinyl chloride(UPVC) pipes

According to researchers Xiong et al. (authors of the article – The application of life cycle assessment for the optimization of pipe materials of building water supply and drainage system), the energy consumption of UPVC pipe in the building drainage system could be reduced by about 86% when compared to that of galvanized steel pipe and copper pipe.

Advantages of Plastic Pipes

  • With plastic pipes, there is no problem of corrosion.
  • Plastic drainage pipes are highly resistant to acidic waters.
  • They are free from damage due to thawing and freezing of water in closed pipe.
  • Installation, joining and bending of plastic pipes is easy.
  • This water line pipe material is light in weight, and hence easy to transport and handle.
  • The major advantage of plastic pipes is they are cheaper as compared to other pipes.

Disadvantages of Plastic Pipes

  • In case of fire, this water line pipe material catches fire easily as it has low resistant to fire.
  • The coefficient of expansion of plastic pipe is high.
  • Plastic pipes are less eco-friendly, as its production releases harmful chemicals.

Plastic Pipes Manufacturers

The popular plastic pipes manufacturers:

  • Jain irrigation systems Ltd.
  • Astral poly technik Ltd.
  • Finolex industries Ltd.
  • Prince pipes and fittings Ltd.

06. Copper Pipes

Copper pipes, once upon a time, were widely used for house drainage system such as supply tubing for toilets or pedestal sinks. However, this hot water pipe material has been replaced by plastic pipe because this pipe is quite expensive now. This water line pipe material cannot sustain cold climates and is likely to burst if water freezes inside. Copper pipes are frequently used in the construction industry for residential water supply lines, as well as drain and vent lines. This water line pipe material is available in soft or rigid copper and provides excellent corrosion resistance as well as reliable connections. The nominal diameter of copper pipe ranges from 6 to 200 mm.

Advantages of Copper pipes

  • Copper pipes have high durability, with a long lifespan of up to 70 years.
  • These pipes are light in weight, which makes them easier to work with.
  • Copper pipes are more environment friendly than plastic pipes, as they do not emit harmful chemicals during manufacturing process.
  • Copper pipes are recyclable at the end of their service life.
  • Copper has high fire rating, hence it is resistant to fire. For areas which are prone to fire, copper pipes can prove to be very useful.

Disadvantages of Copper pipes

  • One of the major disadvantages of copper pipes is that they are costly. According to researchers Asadi et al (Authors of the article – Environmental and economic life cycle assessment of PEX and copper plumbing systems: A case study) PEX piping, a type of plastic pipe, when used instead of the traditional copper piping systems in residential buildings, would considerably reduce the total cost of the building by over 63% over its life cycle.
  • Copper pipes are not recommended in cold climates, as there is a potential risk of bursting of pipes if the water freezes in it.

Copper pipes Manufacturers

The following are popular copper pipes manufactures

  • Shanghai Metal Corporation
  • Kwality Pipe & Tube Industries

Takeaway

Choosing the right drainage pipe can take a great deal of effort. Depending on the material and style, you may need to change the drawings or blueprints for a project, or vice-versa. This article has summarised all the popular types of pipe materials, with their advantages and disadvantages, which will help you make a wise decision.

We have got a detailed guide on the popular PEX pipe, make sure you check it out:

Want more information on 6 inch ductile iron pipe? Feel free to contact us.