Nippon Steel Corporation

Hitachi Zosen Corporation

Toshihiro Ishibashi

Kazuo Fujita

Teruyuki Wakatsuki

Takeshi Hioki

Yasushi Horiuchi

Yasushi Takeshima

Akira Inagaki

Hiroyuki Hasegawa

Hiroaki Hadano

Yoshimi Toriyama

Masao Kurokawa

Mitsuru Nakamura

Ichizo Taguchi

Yukio Noguchi

Jun-ichi Tsumura

Yutaka Toda

An apparatus for cooling thin-webbed H-beam steel includes means for forcibly spray cooling the flanges of the H-beam in intermediate and final hot rolling zones. The cooling is based upon tracking information with respect to predetermined positions along the length of the H-beam. A plurality of flow quantity control blocks are disposed in parallel with each having a three way valve having a water supply side port, a nozzle side port, and a water drain port. A plurality of on-off valves connect the nozzle side port to nozzles in a nozzle group to select nozzles based upon the flange width of the H-beam. A variable throttle mechanism maintains pressure loss at the water drain side equal to pressure loss at the nozzle side. Switching of the three way valve of one flow quantity control block can be carried out without affecting other flow quantity control blocks.

Apparatus for cooling thin-webbed H-beam steel

The invention is directed to provide a rolling method which enables an enlarged range of reduction ratio in sizing-rolling in the common drive system. The invention provides that when tension applied to rolled material between the upstream and downstream-placed mills is made higher than a value that tension/average resistance to deformation of rolled material is 0.2, the upstream-placed mill is caused to perform force rolling, and when compressive force of the rolled material is made higher than a value that compressive force/average resistance to deformation of rolled material is 0.1, the downstream-placed mill together with the upstream-placed mill are caused to perform tensile rolling in the common drive system. The rolling methods provides a stable rolling in a larger sizing range without decrease of diameter or buckling of rolled material.

Rolling mill driving mechanism

A thin-webbed H-beam steel having a web thinner that flanges is produced by forcibly water cooling the outer surface of the flanges during an intermediate hot rolling prior to a final hot rolling by cooling to less than 700.degree. C., interrupting the cooling to return the temperature to greater than 700.degree. C., and repeating the cooling and interrupting in order to refine the microstructure of the surface of the flanges to a predetermined depth from the surface; final-hot rolling the intermediate-hot rolled H-beam steel; and forcibly water cooling the flanges of the final-hot rolled H-beam steel in a manner such that the web does not wave during this forcible water cooling, and such that upon completion of the forcible water cooling, thermal stress, generated in the web during air cooling to room temperature, does not exceed the buckling strength of the web.

Process for producing thin-webbed H-beam steel

Growing community of inventors

Kitakyushu, Japan

Toshihiro Ishibashi