Prise winners list

The company established a groundbreaking manufacturing process for thick steel plates and developed highly-efficient, high-strength thick steel plates for construction and industrial machines and energy plants

Chiyoda-ward, Tokyo
JFE Steel Corporation
Other award winners
Takayuki Ito, Satoshi Kamioka, Tetsuo Sakiyama, Minoru Suwa, Akira Tagane, Seishi Tsuyama, Akihide Nagao, Kenji Hirata, Norimi Wada
Recommended by
The Japan Iron and Steel Federation
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Shikanai, Nobuo  (53)
Director, Intellectual Property Dept

Having our manufacturing process completely online was our thirty years' dream. We achieved that dream by introducing the induction heating
summary

The company established a technology for control of metal's microstructure by making use of rapid heating and tempering in the manufacturing process of thick metals. This new technology enabled them to achieve the high strength, high delayed fracture resistance (very difficult to break), low-temperature toughness and good workability for welding metals together at the same time. The company also developed large induction heating equipment that effectively controlled this process and installed it in the rolling line to improve productivity and reduce energy consumption drastically. With this technical innovation, the company successfully produced a series of new highly efficient, high strength thick steel plates having tensile strength of 780 to 1200MPa (mega pascal). These steel plates are used for large structures including an ultra-large 600t crane.

summary

It took too many hours to perform heat treatment for tempering. This was the biggest problem for making the work process online

Steel plates that are used for construction and industrial machines are manufactured through many work processes. A steel block is heated to soften, extended with a rolling machine and then cooled. Finally it is tempered to have proper strength and extension.
"If we can construct a continuous production line, we can perform mass production effectively. Therefore we have been trying to make the manufacturing process online since more than thirty years ago. However, we could not make the tempering heat treatment process online till the end because it took too many hours to perform this process. 
Treatment times for the respective processes must be adjusted properly to run a production line smoothly. If one work process takes too much time, waiting time occurs and the entire process is affected accordingly. 
The tempering heat treatment process was the biggest stumbling block in manufacturing of thick steel plates. In this process, a cool steel material had to be heated up to about 600C, and if it was heated rapidly with strong firepower to shorten the treatment time, the quality of the steel plate surface was changed.
"We have studied for tens of years to find a new heat treatment method that could replace the conventional gas-fired furnace. With a technology that was developed by electric-appliance makers, a new method called "induction heating" that used a magnetic coil was developed and used around 1995.
The mechanism of induction heating is the same as that of an IT cooking device. A magnetic coil is used to create a magnetic field, and when a metal is put there, an eddy current flows within it by electromagnetic induction and heat is generated by electric resistance of the metal. People used to say that a large amount of power equivalent to that of a small thermal power plant was necessary to introduce induction heating into heat treatment of thick steel plates. However, the technical innovation by electric appliance makers enabled drastic power saving in inductive heating.

New products were manufactured by introduction of inductive heating

Utilizing the technical innovation of electrical appliance makers, we started our basic research of induction heating in the late 1990s. When we started our research on practical use of induction heating in 2003, we began to see the possibility of establishing a new technology.
In induction heating, heat is generated on the surface of metal and heat is transferred from the surface to the interior just like the conventional method. However, we found that we could heat a steel plate rapidly without changing the metal texture. Then we adopted a method of heating a steel plate several times, not a time, up to the target temperature of 600C.
We repeated our patient works in our research and development. We changed the heating temperature and time, observed the change of metal texture and conducted a strength test each time.
"We cannot see the interior of metal and so have to guess how heat is transferred from the surface to the interior in computer simulation. Therefore a method successful for a small test pieces sometimes cannot be successful for an actual steel plate."
We spent more than three years studying invisible heat transfer and finally found the optimal number of heating times and treatment conditions.
Based on those results, jointly with an electrical appliance maker, we designed and developed new large induction heating equipment. There had been no large induction heating equipment in the world that could be installed in the production line of thick steel plates.
The newly developed heat treatment process by induction heating achieved the heating speed 70 times faster than that of the conventional gas-fired furnace. The company started operation of the new production line for thick steel plates, which used the heat treatment by induction heating, in November 2003. The use of induction heating had additional merits.
"The new method enabled us to make the heat treatment process online, which was our longstanding problem, and enabled mass production and also reduced emission amount of CO2 to 1/10 of the convention gas-fired furnace. In addition, we succeeded in development of new products of high efficiency and strength."
By using several induction heating equipment, we could control the heat treatment precisely and manufacture highly value-added thick steel plates.
This new heat treatment method was named "heat-treatment online process (HOP)", and the new products manufactured in the HOP were maximum 30% lighter in weight than the conventional products of the same strength. Currently the new steel plates are used for large self-propelled cranes, shovels and bulldozers. The new steel plates also improve the fuel efficiency significantly because weight of vehicles is reduced.

JFE Steel Corporation

http://www.jfe-steel.co.jp/

Established:
Apr. 2003
Capital:
239.6 billion yen
Employees:
14,513 (as of Dec. 2009)
Brief information:
Established by integrating NKK Corporation and Kawasaki Steel Corporation in steel business. The company is No.6 in the world ranking of crude steel production (according to the survey by the World Steel Association in 2008)

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Image1
Image2

A metal piece is cut into a 0.3 µm thick slice to produce a test sample. The sample is observed with an electron microscope.

Image3

The hot-working test equipment applies heat and strain to a test piece to see how its metal texture changes. This equipment tests the rolling and heat treatment processes in simulation in the laboratory.

Image4

This Amsler testing machine applies force of 200t at maximum to a test piece to check its tensile strength.

Image5

This transmission electron microscope observes the interior texture of metal in the level of atomic crystal. It checks how the metal texture is changed by heat treatment.