TMT From Ship Breaking – ‘Unfit’ For Commercial Use
Circular economy is the need of the hour as the world takes steps into future with lesser emission levels. Ship recycling in India is one of the main sources for domestic ferrous scrap generation. The mills procure the material like ship steel plates and melt and re roll it into the new material like TMT rods, bars, structural steel, construction steels, plates and sheets, billets, and ingots etc. which can again be used for building new vessels.
Previously, Metalogic reported that the right way to reuse the scrap extracted from any source is by first melting it and then shaping it into any other material for better chemical and physical properties.
It was seen that some re rolling mills were re rolling the ship plates or other scrap obtained from ship breaking process into TMT bars which was helping them to save production cost, however the outcome i.e. the TMT obtained from the above-mentioned process is said to be highly ‘unfit’ for commercial use over several issues found in the final product.
Industrial experts have already highlighted the concern on uneven chemical composition and physical properties of TMT throughout its length thus lacking ductility which is enough to suggest that material is unfit to use in commercial aspects as TMT requires uniform composition throughout.
In this aspect, a study was heard to be conducted by stakeholders to check the commercial viability of the material. After concrete results, it also came to light that over absence of concrete records of composition of ships plates (grade varies in different areas of a ship and different ships) it is almost impossible to trace the grade of plates being used in the production of TMT bars.
Additionally, the bar manufactured from the stated process is also having unknown chemical properties or grades across the length of the bars, which means it won’t be possible to tag the strength and grade of the TMT, as per the QCOs.
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The sources have also informed Metalogic that so far, such material fails to meet several requirements of IS 1786, however few recommendations have been made to reach the final conclusions of the study which includes -
·??????? it is essential to identify the chemistry of the material at ship breaker’s end and the material should only be allowed to sold along with its complete certificates.
·??????? In order to tag the material with the grade the large data set is required for testing purpose in labs which includes tests for bond behavior with concrete, tension tests, RCC behaviors, long term durability, and corrosion resistance tests.
·??????? Proper investigation into the suitability of steel plates for rolling bars needs to be conducted amidst its irregular thickness levels across areas.
Written by Rajat Kaushik
Ex-Industrial Adviser, Ministry of Steel at Government of India | IIT Kanpur'79
1 年Part 2: The representations continued from Gujrat Rerollers Association and Ship Breakers Associations, who were also pointing out the fact that 2-2.5Million Tonnes of such scrap is generated from ship breaking and used for rerolling, melting of it is a waste etc etc.? Infact the relevant technical committee in BIS deputed a team of experts to visit Ship Breaking Yards in Gujrat and submit a report. The team reported the actual methods on breaking a ship, segregation of plate cuttings and different materials commenting that perhaps a system could be developed to segregate the plate cuttings as per size/composion after detailed study.? I understand the issue remains un-resolved. And recently, Min of Steel again has constituted a Team to study all related issues de-novo and recommend suitability of such plates for mfg of TMT bars or otherwise . I am not aware of the status/ findings of the report.? In the meantime, I understand ship breaking activities continues and production of Cold Twisted Bars (which some people call FAKE TMT BARS) , to the extent of 2-2.5 MTPA continues , and as far as I am aware, WITHOUT BIS MARK/Certification, notwithstanding the Quality Control Order of March 2012 as amended from time time.
Ex-Industrial Adviser, Ministry of Steel at Government of India | IIT Kanpur'79
1 年Part1: Ship Building Plate Steel, are very good quality steel which is also standardised/certified in different national/international standards. However, here the contentious issue is segregation, sampling and standardisation of diff grades of steel plates used in fabrication of ship as per physical/chemical properties, so as to create a history of the material to qualify it as an input material for prodn of TMT bars as prescribed in IS 1786. I also remember Ministry of Steel , based on representations from TMT manufacturers in Gujrat and adjoining states producong TMT bars, engaged MECON and Dasturco on two different ocassions to study the quality related issues and suitability for prodn of TMT bars. The two study reports certified that ship building plate steel are high quality material as good as or even better than the steel prescribed in the IS 1786. Based on these reports, TMT manufacturers pressed their demand for allowing ship building plate material as a input material in IS 1786. However, the Technical Committee in BIS did not allow it in the absence of history and chemistry of various types of plates used in ship building.
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1 年Re-Melting and ensuring homogeneity in the mix is one way to re-utilise Ship breaking. Not only Ship breaking -> TMT. The issue is applicable to all forms of circularity. Critics are always there for any process/ concept.
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1 年This is a truth that TMT bars manufactured with ship plates can never be as per international standards as plates from different location of the same ship have different chemistry and sorting each and every plate through spectrometer is not an easy option. The best way to use these plates is to melt them in an Electric Arc Furnace making steel as per required chemistry of the grade desired . This method is not possible in Pakistan as the cost of electricity is perhaps highest in the world. Here we use shredded steel scrap of known chemistry and melted in induction furnaces and with some additions the required grade is obtained. Ship plates are rolled by small hand rolling mills producing Cold Twisted bars used by people making cost saving houses with ground plus one floor only. Once TORSTEEL* bars were used as per BSS Standard but now it now TORSTEEL* makers have switched over to TMT bars.