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A committee set up by India’s Steel Ministry has reportedly rejected using ship-breaking steel plates for TMT-bar-making (also called rebars). Non-standardised offerings and the absence of wider data are seen as major reasons for rejecting the proposal.
The recommendations by the committee, reviewed by businessline, stated it could not “conclude and devise an SoP ( Standard Operating Procedure) for usage of ship plates without testing of chemical composition....” It recommended that ship-breakers can “sell the plates along with grade certificate and chemistry”.
The committee consisted of officials from MECON, NISST, Ministry of Ports, Shipping & Waterways (MoPSW), Bureau of Indian Standards, Material Recycling Association of India (MRAI), MSTC Ltd, Ship Recycling Industries Association and Gujarat Maritime Board.
The committee members, who visited and collected samples from Gujarat’s Alang – Asia’s largest ship-breaking yard, said ship sides and bottom plates were subject to “different types of stress” in various directions. It also said the samples collected were not up to the mark in terms of being representative of hulls underwater, mid-ship or above-water level areas.
Comment on the rebars made
Samples of different thicknesses were collected from three shipyards – namely plots 39, 13, 23 and 24 – and these were collected from various parts of ships used in international and coastal trade. The samples collected were rolled into TMT bars of different sizes (8 mm, 10 mm and 12 mm, respectively) and lab tests were carried out.
On the finished products (rebars) made, the committee pointed out that “these rebars cannot be graded directly” and there was a “variation in samples of each diameter (and) are differing significantly”.
“In order to gain confidence for use of these steel rebars for structural purpose, a large size data is required,” adding that “the ...behaviour of beams, columns and joints have to be studied with these rebars.” Comparison must also be made with the market-available rebars to understand and demonstrate the composite actions in elastic and plastic rotation.
The long-term durability study of these rebars with concrete has to be explored and compared with the conventional ones, it said.
Corrosion resistance tests need to be carried out, and it will be helpful in deciding on “wider application in coastal areas”.
Industry Push
During its study, the committee observed that the industry focuses on making TMT bars “instead of making grills and other bars” since the market for the latter products “is very limited”.
As per the data submitted by industry associations, if direct rolling of reclaimed ship plates into TMT bars is allowed, then the melting cost of ₹9,000 per tonne can be avoided. However, there will be an additional cost of ₹3,000/tonne on rolling reclaimed ship plates directly into TMT as compared to rolling ingots in an automatic TMT mill. Net cost savings of ₹6,000 per tonne will be if the reclaimed plates are directly rolled into rebars.
To queries raised by the Ministry officials in September on whether other forms of steel can be made from ship scrap, it was said that ship plates” can be used in manufacturing of thin strips” that are used for packaging, small squares, hexagonal and rounds, and bars of diameter less than 8 mm, small size angles, channels, window sections, etc.
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