Addressing participants on the occasion of the “virtual launch” of Asia’s first continuous galvanised rebar (CGR) facility on June 29, 2020, Union Steel Minister Dharmendra Pradhan informed: “As India is on its way to scaling up infrastructure projects, the use of galvanised rebar in construction is set to rise.”
“India has a coastline extending over 8,000 km and corrosion in salty coastal atmosphere leads to frequent maintenance requirements,” he stated.
“Galvanising ensures that the zinc coating is of a standard quality and offers resistance to erosion. Galvanised steel and rebars are environment-friendly and cost-effective,” he said, adding that usage of zinc in the steel industry will rise as will the use of galvanised rebars for construction thereby unlocking the great market potential of zinc.
Due to its ability to enhance durability of infrastructure, CGRs are best suited for power, telecom, highways, ports and bullet trains, he added.
Growing Market for Zinc
The International Zinc Association (IZA) in collaboration with Madhav KRG Group, one of the leading steel makers in North India with annual liquid metal and TMT production of 4 lakh tonnes and 3 lakh tonnes respectively, has launched the manufacturing facility with support from Hindustan Zinc Limited, the world’s second largest zinc miner with 78% market share in the country’s primary zinc industry.
Situated near Gobindgarh in Punjab, the 30,000 tonnes plant will churn out zinc-coated Tempcore TMT bars, with the steel maker having the certification from CRU Group to use the Tempcore brand.
Zinc demand is rising with a CAGR of 4-5% for the last decade and about 60-65% of all zinc produced is used to save steel from corrosion.
“India is the fastest growing market for steel protection and for sustainable infrastructure galvanisation is essential,” said Andrew Green, Executive Director, IZA.
The government makes buildings for 70-80 years while 200 years should be the goal, noted Vedanta Group CEO Sunil Duggal suggesting that CGRs ensure superior bendability and formability that are needed for hydel projects, railway tracks and hardware products.
The main advantages of CGRs are:
- CGR process produces a coating that is almost pure zinc except for approximately 0.1 micron of intermetallic alloy layer at the zinc/steel interface.
- The thin alloy layer remains the same in thickness for all masses of zinc over it and is not affected by the grade of steel substrate, i.e., reactive steels are not an issue with obtaining good adhesion.
- With no thick zinc-iron alloy layers, the coated bar can be bent, stretched, or twisted without cracking or flaking the coating, regardless of the total coating mass.
- There is no zinc loss due to brittleness during forming in the field and repair requirements are minimal.
- While ensuring superior corrosion resistance in concrete, the CGR coating process is flexible – as few as one or as many as eight bars can be run at a time. It is also possible to convert coiled black rebar into coiled CGR.
Boosting Steel Life
The TMT line is the first indigenously built in Asia, said Sudhir Goyal, Managing Director, Madhav KGR Group, informing that the coating thickness is 80-120 microns.
“The CGR process has lower thickness thereby saving up on zinc while 350 GSM coating increases steel life. CGRs are best for heavy construction and for multi-storey construction in hilly tracts such as J&K, Uttarakhand and Himachal Pradesh thus the government should make it mandatory to guarantee safety,” Goyal opined.
The Modi government’s bumper investments in infrastructure and the need to ensure safety and longevity in construction are driving the galvanised TMT market to newer heights.