- Sumitomo Metal Industries, Ltd.
- Manufacturing Technology for High Quality Very Thick Steel Plate -
Sumitomo Metal Industries, Ltd. (Sumitomo Metals) has received the Minister of Economy, Trade and Industry's Prize in the Manufacturing and Production Process Category of the 4th Monodzukuri Nippon Grand Award for development and commercialization of technology to efficiently manufacture high quality very thick steel plate by continuous casting. The award ceremony was held on February 15, 2012 at the National Graduate Institute for Policy Studies in Minato-ku, Tokyo.
1. Development Background
Steel plate as thick as 100 mm or more is used for dies,
large industrial machinery, bridges, and offshore
structures. The steel slightly shrinks when it solidifies.
Thus, when slabs, the base metal steel plate, are cast,
porosity formed with a large amount of pores of about 2 mm
in diameter is formed at the central part of the molten
steel. If the steel plate is not too thick, porosity is
compressed and does not cause any serious problem. However,
when very thick steel plate is manufactured from slabs as
thick as about 300 mm by a continuous casting machine for
mass production, a reduction ratio* that is sufficient to
compress porosity is not obtained. This is why slabs made
of large-section ingots are needed to manufacture very
thick steel plates, resulting in low productivity and high
costs.
2. Features of Awarded Technology
Sumitomo Metals installed a reduction roll inside a
continuous casting machine at Kashima Steel Works and
conducted a test to analyze the relationship between
solidification and porosity formation. We then found out
that the forming of pores can be efficiently reduced when
the slab surface is compressed just before the central part
of the slabs is completely solidified at the time when
there is a sufficient difference in temperature between the
cooled surface and the hot central part. This finding has
enabled production of very thick plate by continuous
casting for mass production. The new technology to reduce
porosity forming by reduction within the continuous casting
machine has been named the Porosity Control of Casting Slab
(PCCS) technology. Development of the PCCS technology has
enabled a reduction in production lead time from about
three months to less than one month and cut costs
significantly.
3. Future Developments
Sumitomo Metals plans to apply the PCCS technology to high
grade very thick steel plate for the energy sector, which
has high growth potential, and thereby ensure stable
quality and short delivery time.
4. Reference
" Monodzukuri Nippon Grand Award"
Monodzukuri is an art of making goods that has supported
Japanese culture and industry.
The Monodzukuri Nippon Grand Award was established to
recognize the development of monodzukuri and pass it on to
the coming era by rewarding those individuals whose
achievements are on the cutting edge of monodzukuri. Since
2005, the Ministry of Economy, Trade and Industry and three
other ministries have been collectively promoting this
Award.
Note*
The reduction ratio indicates how thinner the steel plate
becomes after the hot rolling process.
(Thickness before hot rolling - thickness after hot
rolling) / (Thickness before hot rolling) X 100(%)