Nippon Steel Corporation

Katsuyoshi Kobayashi

Hiroshi Ikegami

Kozaburo Ichida

Nobuyoshi Nishihara

Satoru Miyasita

Masato Fujioka

Naoki Otsuki

Koichi Yuta

Toshiya Yonezawa

Masahiko Taniguchi

Steel strip is continuously annealed while successively travelling through a heating, soaking, primary cooling, overaging and secondary cooling zone in an annealing furnace. In the overaging zone, an endless steel strip is allowed to run through a passageway that extends spirally from the entry end of the overaging zone to the point where overaging is completed, at a given distance in the direction of radius. The guide strip travels at the same speed as the steel strip being processed that is delivered from the primary cooling zone. On the entry side of the overaging zone, the strip being processed is laid over the guide strip so that the two strips spirally travel through the overaging zone side by side. The processed and guide strips running together are shifted out of the spiral passageway at the point where overaging is completed. Then, the processed strip is separated from the guide strip by shifting at least one of the two strips. While the separated processed strip is delivered to the subsequent secondary cooling zone, the guide strip is returned to the entry end of the overaging zone for the next trip through the spiral passageway. Helical devices are used for changing the position and running direction of the strip being processed and the guide strip. The overaging furnace is annular in shape, provided with a number of radially disposed guide rolls on the inside. Each guide roll has a plurality of guide grooves in which both edges of the guide strip are fitted.

Method and apparatus for continuously annealing steel sheet

A continuous heat treatment furnace for heat-treating a metal strip by passing the metal strip continuously through the interior of the furnace, comprising a wall of an air-permeable solid having a three-dimensional skeleton structure or net-like laminate structure satisfying the following requirement: ##EQU1## wherein .delta. stands for the thickness (m) of the air-permeable solid wall, a.sub.p the specific surface area (m.sup.2 /m.sup.3) of the air-permeable solid wall, and .epsilon. a porosity of the air-permeable solid wall, is arranged between the confronting surfaces of the strip.

Continuous heat treatment furnace

A shaft reduction furnace is provided with a pressure equalizing chamber for supplying raw materials such as ores in the furnace. The interior of the furnace is separated by a dividing plate into an upper portion and a lower portion. A pipe path through the dividing plate communicates the upper portion with lower portion. The upper portion and the pipe path form an inside ore hopper for supplying ore continuously into the lower portion of the furnace, thus omitting the conventional ore hopper of pressure-proof-structure provided separately outside of the furnace.

Shaft furnace

A vertical strip heating furnace includes at least two vertical direct fired heating chambers which are arranged in parallel which are communicated with each other. A separation chamber for housing inside furnace rolls at adjacent pairs of the chambers is provided in at least one location. The inside furnace rolls are separated from the main flow of the combustion gases and the temperature of the atmosphere in the chambers housing the inside furnace rolls is adjusted to within a fixed range. This strip heating furnace is capable of large capacity processing and is designed to save energy, and the inside furnace rolls are free from breakage due to thermal stress.

Vertical direct fired strip heating furnaces

A furnace product is permitted to flow out by gravity from the opening defined between the lower end of a furnace wall and a furnace bottom and to accumulate on the circumferential portion of the furnace bottom with a reposing angle inherent to the product, with the accumulation being drawn out of the furnace from the circumferential portion of the furnace bottom. The furnace bottom is formed with a diameter larger than the inside diameter of the lower end of the furnace wall and vertically spaced from the lower end of the furnace so as to provide an opening therebetween through which the furnace product is allowed to pass a discharging device comprising a reciprocating raking arm with its end movable across the circumferential portion of the furnace bottom operates to remove product therefrom.

Growing community of inventors

Kitakyushu, Japan

Katsuyoshi Kobayashi