by webmanager webmanager

An Overview of Manhole Covers Manufacturing In India

top manhole cover manufacturing in india - Govind Steel

The proper disposal of human waste has been solved by the sewage systems built across the various parts of our nation. And what keeps the sewage system separate from the actual city are the manhole covers. The history of the manhole covers is rather varied – what started as stone manholes covers are now made of cast iron.

How are Traditional Manhole Covers manufactured?

Most top manhole covers manufacturing is carried out cast iron foundries as the modern-day manholes are made out of cast iron. The process is fairly simple theoretically – the cast iron is melted and then poured, or cast, into a mold. In many cases, ductile cast iron is also preferred because of its greater strength and is generally found in and around airplane terminals. What adds more strength and durability to the manhole covers made of gray cast iron is the alloying element(s) – carbon and silicon. And in the case of ductile cast iron manhole covers, manganese is added to the molten iron that provides greater strength and malleability.

What are the Raw materials used besides Cast Iron?

Apart from iron, the other raw materials required in manhole cover manufacturing is green sand -which is sand bound together with clay. It is mainly used to produce the molds which are further used to store the molten iron. The sand mixture is about 90% silica sand, 4-10% clay, 2-10% organics and 2-5% water.

Design & shapes

All manhole covers are first structured in aluminum or wood as a model. This model serves as the key design and is used as a reference to make the mold and then the molten cast iron is poured. The intricate designs on the surface are often created by skilled artisans who personalize them. Coming to the shape of it, all manhole covers are round since it cannot go beyond its assigned diameter. Round manhole covers are convenient to move around as they can be rolled.

Assessment of the Quality

The key to controlling the quality of manhole covers is assessing the proper percentages of iron, carbon, and alloying metals. Once the casting is complete, the strength and ductility of the cast irons are tested to assure reliability. And lastly, the strength and ductility are determined by casting bar test specimens from the same metal used to cast the manhole covers.

Govind Steel is one of the leading foundries of India with an installed capacity of 24,000 MT. Apart from that, Govind Steel has been recognised as one of the top manhole covers manufacturing companies in India as well. Please visit our website at to know more.

by webmanager webmanager

Why choose ductile iron manhole cover over cast iron?

ductile iron manhole covers

When it comes to manhole covers, traditionally, they are made using cast iron. But over the years with the introduction of new and improved forms, ductile iron has proven itself as a great alternative. Many pieces of research later, it has been found that ductile iron is considered a better choice than cast iron because it can resist the same traffic loads with relatively lower self-weight and are less brittle than cast iron. Here is a list of its core strengths:

Bend It Like Ductile

Unbreakable yet bendable, ductile iron manhole covers are made from materials like carbon, silver, sulfur and magnesium. These materials tend to add strength and make it more durable in the longer run. But apart from lending to the superb quality, ductile iron manhole covers are easily bendable and have zero risks of breaking. This makes it a perfect choice as it contributes to structural agility.

Easily Compressible

The compressive strength of any metal contributes majorly to its choice of application. To further define, ductile iron has higher compressive strength as compared to any other form of metal. This form of metal can withstand any shape and any intensity of strength thus they prove to be better than cast iron.

Corrosion resistance and core strength

Manhole covers take the brunt of all-natural bodies like rain, sun, frost, and all its extremities. What works wonders, in this case, is the fresh coat of polish that can support the cause. Ductile iron, fortunately, is wear-resistant and corrosion-resistant and does not require the polish to function smoothly. Not only that, but the corrosion resistance also adds to the overall life of the manhole covers.

Low maintenance

Ductile iron, owing to all its properties, is extremely low maintenance and does not pose any harm to the safety hazards of the workers. Since they are easy to lift, low on weight and easy to clean, the pipe maintenance and other sewage conditions make it an ideal choice. It is way less brittle than cast iron thus is designed to be in the manhole frames and holds them perfectly.

To know more about ductile iron manhole covers, visit and read about their history, experience and the high-quality manhole covers provided by

by webmanager webmanager

The Applications of Different Types of Cast & Ductile Iron

As a 55-year old cast iron foundry in Kolkata, we have researched and studied the glorious history of iron thoroughly. The transformation of iron from 3,000 years ago to today is revolutionary and the processes are beyond commendable. Centuries have been spent by the blacksmiths until the invention of the cast iron in the industrial age.

Ever since then, cast iron and ductile iron have evolved its new form while progressing in the terms of its composition, microstructure, and mechanical properties. While there are multiple applications for the modern-day iron made in the cast iron foundries, some of them are listed below:

Grey Iron Applications

Grey cast iron is a type of iron found in castings known for its grey color and appearance caused by graphite fractures in the material. It is mainly used to make cylinder heads, gas burners, enclosures, and housings because of the key characteristics of gray iron and its ability to resist wear and tear, especially when lubrication supply is limited.

Ductile Iron Applications

Owing to its multiple benefits, ductile iron is used to make heavy-duty gears, automotive and truck suspension components, hydraulic components, and automobile door hinges. The fact that ductile iron can be broken down into different grades, yields strength, and is wear-resistant, makes ductile iron, the prime choice. Its ductility makes it another great choice for great designs.

White Iron Applications

Mainly used for mixer paddles, liner plates for ball mills, augers and dies, coal chutes, and wire guides for drawing wires, White Iron is wear and abrasion-resistant. The process that is used to make white iron results in a brittle material that is very resistant to wear and abrasions.

Malleable Iron Applications

Through an annealing heat treatment, the brittle structure as the first cast is transformed into the malleable form. Malleable Iron is the iron that has the ability to retain and store lubricants, the non-abrasive wear particles, and the porous surface which traps other abrasive debris. Malleable iron is used for heavy-duty bearing surfaces, chains, sprockets, connecting rods, drive train and axle components, railroad rolling stock, and farm and construction machinery.

Compacted Graphite Iron Applications

As the name suggests, compacted graphite iron is famously used in commercial applications. Similar to ductile iron, compacted graphite iron is produced by adding magnesium to a desulfurized base iron. The combination of both the properties of creates a higher strength and thermal conductivity product.

To know more about the functioning of a cast iron foundry or the various applications of cast iron, contact and follow

by webmanager webmanager

An Introduction to Grey Iron Castings

Iron castings are created using various melting methods and different methods lead to different types of cast iron like ductile iron, malleable iron or grey iron. Grey iron is a type of iron found in castings which is grey in colour because of the graphite fractures in the material. Grey iron is an alloy of iron and carbon and are typically made by smelting pig iron. Grey iron castings manufacturers claim that grey iron is popular due to its cost efficiency and ability to be made into complex structures.

Advantages of Grey Iron Castings

Grey iron is used for housings where the stiffness of the component is more important than its tensile strength, such as internal combustion engine cylinder blocks, pump housings, valve bodies, electrical boxes, and decorative castings. Grey cast iron’s high thermal conductivity and specific heat capacity are often exploited to make cast iron cookware and disc brake rotors. Grey iron casting also possess traces of phosphorous, sulfur, silicon and manganese in them. The advantages of grey iron casting are:

Heat-Resistant & High Carbon Content 

Grey iron casting is heat resistant, making them ideal for cast iron cookware and kitchenware and the high carbon content of grey iron castings makes it easier to melt, weld and machine the iron castings properly.


Grey iron casting is highly corrosion resistant as it can resist oxidization, which leads to the prevention of rust. This is one reason why they are used for housing purposes.

High Compressive Strength 

Grey iron casting can withstand high compressive force and have high compressive strength. For this reason, they are the prime choice for columns and posts in the construction of buildings.

High Damping Capacity 

Grey iron casting has a high damping capacity, about 20-25 times higher than steel and other iron types which reduces excessive wear & tear, vibrations and inaccuracies on machinery.

High Cost-Efficiency 

Grey iron casting is cost-efficient as they are produced economically in high volumes using an automatic production line or disamatic equipment.

These castings are a popular choice owing to its high thermal conductivity and low cost. There are many foundries that produce grey iron casting all over India. Govind Steel is a 55-year-old company that has become one of the leading grey iron casting manufacturers in Kolkata. The foundry has received numerous awards from the Government of India for its excellence in the export of castings. To know more about our products, visit

by webmanager webmanager

An Overview of Ductile Iron Manhole Covers

ductile manhole covers in India - Govind Steel

Depending on the application and requirements of an area, the accessibility and precision of ductile iron manhole covers are defined. However, one crosses by and witness a manhole cover everyday, no one pays attention to the details. The details as to how sturdy, long-lasting, and efficient they are for the required area of application. For the ones who know little about it, let us take a quick look at it.

What are Manhole Covers & why are they important?

Pretty much what the name suggests, Manhole Covers are removable iron, cast iron or ductile iron plates that essentially cover the opening of a manhole to prevent objects and people from falling into it. If you’re installing a new manhole cover or you’re replacing an existing one, measuring the space is key. Finding out the basics of a manhole cover is important to assure a perfect fit and zero-compromise with structural integrity.

What are the different types of Manhole Covers?

Ductile Iron Manhole Cover  

Strong, sturdy, resilient and heavy-duty, ductile iron manhole covers are used over a D400 class. The main purpose of using Ductile iron, also known as cast iron, is because of its strength. This type of manhole cover is used to add a long life span to any application. This kind is particularly used for installation in airports, docks, and other heavy-duty industrial areas.

Recessed Manhole Cover 

More like a holder or an outline structure, Recessed manhole covers essentially have a cut out in the tray so that bricks, paving bricks, cement, and other pavements can be installed. Since the cover is hardly visible, this allows the recessed manhole cover to blend in with the surroundings. It is useful for pedestrian walkways, side footpaths, etc. It’s also an excellent solution for internalized manhole covers. For example, hospitals, workshops, organisations, and societies.

Solid top Manhole Covers 

Places where safety and maintenance need to highlighted, Solid top manhole covers are used for those areas. The idea behind designing these covers is to highlight prominence on a specific floor or a certain area to keep people away from it. These are installed in the areas where one needs to highlight a certain architecture as opposed to hiding it. It is an anti-slip surface where the top is visible or even raised too. The starking contrast between the solid floors and the solid top manhole covers makes them easy to identify.

Where to find the best Ductile Iron Manhole Covers in Kolkata?

Govind Steel Company Limited is a 55-year-old Brand, making it one of the best foundries in India. We have a varied range of products like Ductile Iron Manhole Frames, Covers and Grates, Surface Boxes, Valve Boxes, Counter Weight, Industrial Castings, Manhole Frames and Recessed Covers, etc. For more information about foundries and to view our varied range of products, call us on +91 33 25309445, or leave us a mail on and be rest assured to get a reply within 24 hours. You can even visit us at 219, Chittranjan Avenue, Kolkata – 700 006.

by webmanager webmanager

Manhole Covers: History, Characteristics & More

There are many everyday objects that we come across and never wonder about. From something as simple as a comb while grooming ourselves in the morning to the manholes we cross over as we walk down the roads. Have you ever wondered what goes behind making the cover of a manhole? Manhole covers date back to the era of ancient Rome when they were made of stone.

Manhole covers, as we all know are the removable lids atop a manhole, usually big enough for a person to pass through. They are used to access underground pipelines and vaults. They started off as slabs of stones and sometimes, pieces of wood and this continued till the 18th Century. In the 19th Century, modern ductile manhole covers were developed. For the last 200 years, manhole covers are made of cast iron in varied designs.

While circular manhole covers are what we frequently come across, manhole covers are also available in different shapes like rectangle and square and varied sizes. There are also triangular manhole covers in some parts of the world. Here are some interesting characteristics of different types of manhole covers:

  • Choosing the right cover: When searching for the right manhole cover, many factors have to be considered. Construction, dimension specification, as well as the positioning of the manhole, have to be kept in mind while purchasing the manhole cover.
  • Division as per weight: Different manhole covers weigh differently, depending on the load they have to deal with. A manhole cover on an airport runway will have to be much heavier than a cover on the road, whereas one on a pavement which has only pedestrians and cyclists is lighter.
  • Locking of manhole covers: As an extra measure of security, manhole covers have the option of being locked up or welded, especially in case of manholes on roads where racing occurs. It may sound bizarre, but often manhole covers are stolen to be sold as metal scrap.
  • Difference between shapes: A round manhole cover is often chosen because the chances of it falling through its circular opening are very low whereas it is possible with square covers. They are much smoother, have smaller surface area, are easily movable as well as easy to lock in place.

Ductile manhole covers and manhole frames are invisible products that make our life smoother. Made of cast iron, they are sturdy and essential for the running of any city. Govind Steel, a leading foundry in India constructs varied types of manhole covers and frames as well as manhole grates. They have different shapes, sizes and designs along with other cast iron and steel products. To check out their vast range of products, visit

by webmanager webmanager

All About Investment Casting – Process, Products & Benefits

We have read and learnt about the different types of metal castings in an iron foundry but this blog talks about the versatile form of casting – Investment Casting. Often known as ‘lost-wax’ casting, this process uses an expendable mould to create well-defined and fine surfaces. The precision and versatility of this process make it the number one choice for well-detailed cast objects. The moulds can be used to achieve the desired shape as it can be carved in wax and can be coated. Sure, this process tends to be a little more on the expensive spectrum but the end products can be complex and smooth as opposed to sand casting.

Common Investment Casting Products 

Operational pieces of precision machines are often made via Investment Casting. For example, the fans, camera and other engine parts with complex shapes that need mobility and fine surfaces are made via Investment Casting. It is commonly used for detailed jewellery, vintage and contemporary decor items.

The Investment Casting Process

The basic structure of an Investment Casting Process consists of an expendable pattern of wax mould: a ceramic mould material, and a kiln.

Expendable or Wax Pattern

This wax pattern is an exact replica of the final product one needs. It is filled in with an injection mould made of aluminum or steel. These moulds are usually machined, 3-D printed and hand-carved and owing to this, the process is more expensive than sand casting. Once the injection mold has been created, wax patterns are fast-tracked to allow the cast to solidify.

Pattern assemblies

The second step is to assemble these wax patterns and allow multiple items to be cast together in the tree formation (the casting system). Made from solid wax, tree-like channels are used to carry molten metal to the final product. To ensure efficiency, these structures should be assembled carefully.

Ceramic ‘investment’ mold

On assembling the tree structure, the whole thing is dipped in a ceramic bath and is let to dry, These baths are repeated several times to allow each coat to harden and create a thick mold. The tree is then heated to melt the wax and once removed, the mold is heated to a higher temperature and molten metal is poured inside. This process ceramics dipping and heating is the ‘investment’ of investment casting.

Mold removal

The entire process is let to cool down and once that happens, the ceramic mould is removed to unveil the finished product. Once done, if required, additional finishing or treatment procedures are done.

That is all about investment Casting. Find more about other casting processes and products on Govind Steel Company Limited is a 55-year-old company that has continually grown to become one of the largest and leading foundries for Grey Iron Castings and Ductile Iron Castings in India, with an installed capacity of 24, 000 MT. Contact Govind Steel today!

by webmanager webmanager

The World of Expendable and Permanent Moulds in Iron Casting

The true pioneers of Industrial Development and the improving standard of living are the foundries – Metal, Iron or Ductile Iron Foundries across the nation. But do we really understand the actual functioning of the same?
Let us debunk this alien concept by understanding the basics of metal castings and different moulds used.

The process where the molten metal is poured into the mould containing a hollow cavity to get any geometrical shape one wants is casting. This process can be further can be divided into two types – Expendable or Semi-permanent Mould and Permanent Mould. Let us find out what are their functions:

Permanent moulds are made of metal with a high melting point over the metal that needs to be cast. The main purpose of using these permanent cores is because they are simple to use and can be reused. Such moulds are generally used for both low-temperature alloys and iron. The castings from this method have thin walls as they are produced with “close tolerance”. Castings made this way are fine-grained and dense with a smoother surface finish. A few common types of permanent castings are:

  • Low-pressure Casting
  • Gravity Casting
  • Die Casting

Semi-permanent moulds are the ones where the cores are expendable and can result in more complex shapes. Usually, sand, plaster and ceramic is used as the core as it allows the possibility of being taken out or broken down to get the casting out. Such moulds are generally bound with a bonding agent that improves its properties and creates complex, intricate castings. A few of the examples are:

  • Sand Casting
  • Plaster Moulding
  • Shell Moulding
  • Ceramic Moulding
  • Investment Casting

Among the foundries in Kolkata famous as industrial casting manufacturers, Govind Steel is one of them. Govind Steel is one of the largest and leading foundries for Grey Iron Castings and Ductile Iron Castings in India. To know more about the same, kindly visit –

by webmanager webmanager

All About Metal Castings – The process, different types and more

In the history of industrial manufacturing techniques, casting is the oldest one. However, modern advancements in technology have led to a host of casting methods and techniques. But before we get into that, here is what casting actually is. It is a process that allows molten metal to be poured in a specially designed mold to take various shapes Read more

by webmanager webmanager

Choosing Between Ductile Iron And Traditional Cast Iron

Each casting foundry of India is known either for their Ductile Iron or the Traditional Cast Iron or both. While both the types are cast in the same foundry, their properties and varied and how. From applications to different resistance-levels, both the iron types play a pivotal role in the construction industry.Choosing a suitable kind for a particular job is extremely important and knowing the basics, tend to help. Below is a list of few basic differences between Ductile Iron and Traditional Cast Iron.

Read more