What are HFIW steel tubes

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What are HFIW steel tubes

HFIW (High Frequency Induction Welding) tubes are manufactured by cold forming of steel coil into desired shape followed by welding using high frequency induced current. A high frequency coil develops current into the tube ahead of the squeeze rolls. The edges are pushed together between squeeze rolls to produce a joint of welding. The welding of the edges forms a small bead inside and outside the tube. These beads are then scarfed from the tube to give a smooth surface finish. Surface heating by induced current and the squeezing action by rollers are the two main principles behind production of high frequency induction welded steel tubes.

HFIW steel tubes do not need any filler material. This makes the process very fast and highly efficient in production. High frequency induction welding allows us to produce variety of shapes of tube with an almost invisible weld joint that is stronger than the parent material and are suitable for critical applications. The ability to manufacture a high quality and critical welded product, offers architects a flexible solution to design the perfect profile shape for their end application. HFIW is commonly used in manufacturing structural steel tube, transportation & mechanical tubes.

Let’s take a look at the benefits of HFIW process to manufacture steel tube:

1) High Efficiency: High frequency induction welding is an efficient welding process to manufacture tubes as it consumes less electricity than other welding processes.

2) Able to weld very thin walled tube: HFIW is suitable for steel tube with a wall thickness as low as 0.15 mm.

3) High welding speed: High-Frequency allows high welding speeds up to few hundred m/min.

4) Produces welds with very narrow heat affected zones: HFIW process is capable of producing focused heat thereby protecting the work piece from damage. The focused heat produces very narrow heat affected zones near weld bead.

5) Superior weld quality: It provides stronger & uniform weld seams which make the steel tube suitable material for structural applications.

6) Easier cleaning processes afterwards: Induction welding offers cleaner work pieces once they’ve been welded than other welding processes.

7) Highly automated: Most of the steps in the HFIW process can be performed automatically which makes the operation streamlined & time-saving.




Sub – Contractor


M/s. YONGNAM ENGINEERING – Sub – Contractor, for Bengaluru Airport, had a requirement of hollow sections 350 mm X 250 mm X 10 mm from BIAL’s preferred make list suppliers for constructing the Terminal building. The preferred make list suppliers were not able to manufacture the required sizes since they had the capability and capacity constraints. 

YONGNAM ENGINEERING had almost taken a decision to import these sizes from China with a 60 day lead time which would have increased costs. 

The contractor approached APL Apollo Tubes Ltd, for supplying Hollow Sections of size 350 mm X 250 mm X 10 mm. APL APOLLO was able to provide the required sizes and quantity within 7 days of issuing the purchase order. 

This was possible because of DFT (Direct Forming Technology) which is installed only with APL APOLLO in India. This technology helps in giving customized sizes, greater flexibility and minimal lead time. 

Conclusion: APL Apollo has the technology to service Customised Sizes in Minimal Lead Time  


Shapoorji Pallonji & Co. Pvt Ltd

Kartarpur Corridor is a very prestigious project, which is a gateway for pilgrims to visit the Gurdwara Kartarpur Sahib in Pakistan. The project is under the limelight of different international and national media houses as this project can be a stepping stone towards improving ties between two countries. 

The project is scheduled to be inaugurated as per the defined timeline. The contractors of the project were running behind time with their approved vendors for supplying structural pipes & tubes. However, approved vendors were unable to cater to the demand due to shorter lead time. 

Creative Group & Shapoorji Pallonji & Co. Pvt. Ltd approached APL Apollo Tubes and requested to supply the required structural pipes & tubes in a given time frame.

The principals to the project – Land Port Authority of India, a part of the Ministry of Home Affairs, were approached by APL Apollo along with Creative Group & Shapoorji Pallonji & Co, to get the approval along with LOI. A presentation was made by APL Apollo to the concerned authorities which highlighted the manufacturing capabilities along with the credentials of the company.

APL Apollo was given a pre-approval on the 24 July, 2019 & an LOI on the 26 July, 2019 to supply structural pipes. 

APL Apollo started dispatches from 27 July, 2019 and supplied approximately 500 Tons out of the total requirement of 615 Tons within 7days of LOI.

Conclusion: Faster Delivery, Flexibility on Sizes, Proximity of Plant Locations

Tubular Sculpture

Mumbai, Maharashtra, India

Over the years, APL Apollo has achieved a reputation as one of the lowest cost manufacturers by bringing in the latest technology to make optimum use of resources. 

For this INR 2.5 million project, APL Apollo designed and conducted analyses to achieve the architect’s aesthetic vision for a unique tubular steel sculpture. 

Our Project project team combined analytical and physical modeling, created physical models to enable digital workflows, and automatically generated analytical models. Applications were used to manage bidirectional changes in the 3D models and automate the meshing process. 

The project was completed with accuracy in analysis and design that saved 250 resource hours and reduced design costs by 15%.


(Delhi to Panipat)

APL Apollo was tasked with designing foot over bridges between Delhi’s Mukarba Chowk to Panipat’s Haryana, allowing pedestrians to safely cross the roads. For the estimated INR 165 million project, the FOBs also needed to have a 60-meter clear span with ramps and stairs, as well as escalators or elevators if necessary. 

We used 150 metric tons of steel instead of the standard 175 to 200 metric tons to keep the design aesthetically pleasing.

We planned to manufacture the foot over bridges using high strength steel tubes and created a design that is both functional and beautiful.

Role of steel in the aerospace industry

The aerospace industry is one of the fastest-growing industries globally. This Industry is one among the key drivers of the economic growth of India. The segments in the aerospace industry include civil aviation, military aviation and space. This industry manufactures aircraft, space vehicles, guided missiles, aircraft engines, and related components. The industry requires the highest standards of equipment, parts, components and designs. Steel is one of the most widely used materials in the industry due to its fantastic strength to weight ratio. Steel typically comprises around 13% of the materials used in an aircraft.

Steel forms a significant part of the aerospace industry. Owing to its excellent properties, steel is widely employed in the making of engines, exhaust ducts, landing gears, motor cases, fuel tank, springs, fasteners etc. The most important characteristic of steel is its durability. Its strength, hardness and resistance to heat make it ideal for the use. Moreover steel is cost-efficient along with being light-weight. Steel is also easy to weld and can be reformed easily. All these reasons come together to make steel the most favorable material to be used in aerospace industry. 

Let’s take a look at the applications of steel in aerospace components: 

  • Shaft for engines: High quality steel is used for the construction of main shaft of engine owing to the combinations of very high strength and creep resistance. The steels used in the shafts are of medium carbon grades.
  • Landing gears: Steel is also used for landing gears. The high strength and toughness of steel makes it far more suitable to handle incredible amounts of pressure involved during both take-off and landing.
  • Motor casing: Low alloy steel is a perfect choice for motor casing due to its ultra-high strength, wear resistance & ability to withstand tremendous pressure.
  • Exhaust & Engine: The higher temperature resistance of steel makes it an exceptional solution for use in exhaust & engines.
  • Steel Skins: High-speed and supersonic jets also utilize steel in their skin as it is resistant to the heat caused by the friction in the air created by such extensive speeds.
  • Fuel Tank: These too are again made of steel.  

Well, the list goes on and on. The bottom line is that the contribution of steel particularly in the aerospace industry, is beyond match and highly incomparable. Known for its strength and durability against heat and force, steel has become an integral part in the aerospace industry. 

Role of steel in the automobile industry

The automobile industry manufactures and sells automobiles like cars, buses, trucks, and other vehicles. It is one of the key drivers of the economic growth of India. One material that forms the backbone of this industry is steel. It is widely used in the auto industry. Approximately 55% of a car’s weight comes from steel and on average, a vehicle weighs 1200kg – so that’s a large amount of steel.  

Steel forms a significant part of the automotive industry. Owing to its excellent properties, steel is widely employed in the making of vehicle bodies. Steel is very tough and thus is the go-to-choice for making vehicles. It lends strength and ensures safety. Moreover, steel is cost-efficient along with being light-weight. Steel is also easy to weld and can be reformed easily. All these reasons come together to make steel the most favorable material to be used in manufacturing automobiles. 

Let’s take a look at the uses of steel in the making of an automobile: 

  • Structure of the vehicle: The structure of the automobile makes use of a large amount of high-quality steel. One of the main reasons that steel is used in the making of body frames is because of its ability to absorb the impact energy produced in a crash. This ensures safety. It also keeps the overall structure lighter, yet sturdy. As the steel has high tensile strength, it works in favor of the vehicle and enables it to withstand tremendous pressure and force. 
  • Propeller shaft: High-quality steel is used for the construction of a propeller shaft. It is because the propeller shaft should be powerful enough with a high wear-resistant property so it can tolerate bending and torsional load. 
  • Seat frame: The seat frame too utilizes steel. The reason being, steel is strong and this makes it possible for the seat to withstand everyday rigors. Moreover, steel can be easily formed into the desired shape for comfort. 
  • Exhaust Tubes: These too are again made of steel.  

From the total amount of steel used in an automobile, 34% of it is applied in the body structure, panels, trunk closures, and doors. Apart from that, the drive train makes use of 23% of the steel. Another 12% is used in the suspension. The rest of the steel is utilized in the making of the fuel tank, wheel, steering, and braking system. Thus, steel forms an integral part of the automobile industry.

How does zinc contribute to the steel industry

Zinc is found in Earth’s crust in abundance and comes with an array of uses. It is widely used for industrial and biological purposes. Zinc is blue-white in appearance at the room temperature and is the fourth most widely consumed metal. Zinc is used for various purposes. However, 50 percent of it is applied in corrosion protection of steel and iron. 

Zinc is a blessing for steel. Without it, all the steel buildings and bridges are at risk of getting corroded away and collapsing. However, thin layers of zinc are added to the steel to prevent rusting and protect it. The process is called zinc galvanizing. 

The reason zinc is used out of all the material is that it won’t oxidize when exposed to water and air. Moreover, it becomes a strong barrier between the corrosive environment and steel. It prevents the steel from getting corroded by keeping the moisture away from the steel. Moreover, it provides sacrificial cathodic protection and losses itself first if there’s any scratch exposing the steel to moisture.  

The most common process to galvanize steel is called Hot-dip galvanizing. The process requires the steel to be immersed in molten zinc to produce a uniform layer coating. A metallurgical reaction takes place between the molten zinc and the iron in the steel, causing a uniform coating through-out the surface. After it cools down, the steel and zinc form a solid bond that has the ability to last for up to 50-years in normal conditions and with very little maintenance. 

The steel galvanized zinc has various applications: 

  1. Protecting underwater structures: Due to its properties, zinc will corrode first and provide cathodic protection to steel. Thus, it is quite beneficial for structures that are underwater like a ship’s hull, pipelines, bridges, and drilling equipment. If there’s an uncoated area on the steel surface, the surrounding zinc will sacrifice itself to protect steel. 
  2. Automotive: There are numerous parts of car structures composed of steel that are susceptible to corrosion. For these parts, steel galvanized with zinc is used. The zinc coating is very seamless and there is no visible difference in appearance after coating the surface. This coating protects the vehicle’s structure to a large extent from getting corroded and damaged. 
  3. Buildings and construction purposes: This industry makes use of two-third of the zinc-coated steel. The zinc-coated steel is applied in roofing and cladding of buildings. Thus, it protects the buildings well from corrosion.