Hiromitsu Naitoh

Title: Hiromitsu Naitoh and Continuous Annealing of Steel

Introduction

Hiromitsu Naitoh is an inventor associated with Kitakyushu, Japan, and Nippon Steel Corporation. His patent work addresses the continuous annealing of cold-rolled low-carbon steel strip.

Latest Patents

The provided information identifies one patent for Naitoh: “Process for Continuously Annealing a Cold-Rolled Low Carbon Steel Strip.” The process rapidly heats the strip in a direct-fired furnace using a gaseous combustion product prepared at a combustion air ratio of at least 0.8 but below 1.0. Heating proceeds at an average rate of 30 to 100°C per second, from 500°C up to the steel’s Ac₃ point, while limiting the resulting surface oxide layer to no more than 1,000 angstroms.

The method then holds the heated strip between 700°C and the Ac₃ point for at least 10 seconds in a reducing atmosphere containing at least 4% hydrogen, with nitrogen making up the balance. It cools the strip from at least 600°C to a desired temperature at an average rate of 10 to 300°C per second using a gas-and-liquid cooling medium, and removes oxide formed during cooling. Naitoh is credited with 1 patent in the information provided.

Career Highlights

Naitoh’s listed patent reflects work on controlling heating, oxide formation, reduction, and cooling in steel-strip processing. These steps are designed to support continuous annealing while managing the strip’s surface condition.

Collaborations

The supplied information names Hajime Nitto as Naitoh’s coworker. It does not specify the nature of their collaboration or identify him as a co-inventor on the patent.

Conclusion

Hiromitsu Naitoh’s documented invention focuses on a controlled continuous-annealing process for cold-rolled low-carbon steel, combining rapid heating, reduction, cooling, and oxide removal.