Sumitomo Metal Industries, Inc.

Nippon Steel Sumitomo Metal Corporation

Hirofumi Hori

Tetsuya Nakanishi

Kazuhiro Shimoda

Sumio Iida

Masami Imamura

Teruo Onozawa

Yoshimi Imoto

Yuuji Tanaka

Tomio Yamakawa

Hiroyuki Semba

Toshiro Anraku

Shizuo Mori

Akira Motoki

Tsuneo Kondo

K Shimoda

The present invention provide a two-component anti-seizure agent for hot metal working process comprising the first aqueous solution and the second aqueous solution, wherein the first aqueous solution contains 10&#x2dc;30 mass % of sodium silicate equivalent to anhydride to 100 mass % of total mass of the first aqueous solution, and the second aqueous solution contains at least one kind selected from a group consisting of: an organic acid and water-soluble amine salts thereof, an inorganic acid and water-soluble amine salts thereof, a water-soluble amine, a water-soluble alcohol, and a water-soluble metal chloride. When the two-component anti-seizure agent is applied onto disk-roll type guide shoes, it can be provided and maintained on the circumferential surface of the disk-roll type guide shoes without washed away by rolls' cooling water. Thereby, the anti-seizure agent does not adhere to rolls and the rolls and a pipe material do not cause slippage each other. Thus, it is capable to carry out piercing-rolling of the pipe material.

Two-component anti-seizure agent for hot metal working process, and method of manufacturing seamless pipe using thereof

A method of coating uses an anti-seizure agent for hot steel working that exhibits excellent wettability and surface film-adherability. The agent comprises: an inorganic component (first component); sodium hydroxide (second component); water-soluble resins and/or water-soluble surfactants (third component); and water. With the sum of the first component, the second component, and the third component as 100 mass %, the anti-seizure agent contains: 96.5 mass % or more and 99.98 mass % or less of the first component; 0.01 mass % or more and 2.0 mass % or less of the second component; and 0.01 mass % or more and 1.5 mass % or less of the third component, and the inorganic component is one or more selected from a group consisting of AlO, SiO, CaO, BO, KO, and NaO. A coating layer formed solidly adheres to the steel and does not come off in both cold and hot working.

Anti-seizure agent for hot steel working

An anti-seizure agent for hot steel working that exhibits excellent wettability and surface film-adherability comprises: an inorganic component (first component); sodium hydroxide (second component); water-soluble resins and/or water-soluble surfactants (third component); and water. With the mass of the sum of the first component, the second component, and the third component as 100 mass %, the anti-seizure agent contains: 96.5 mass % or more and 99.98 mass % or less of the first component; 0.01 mass % or more and 2.0 mass % or less of the second component; and 0.01 mass % or more and 1.5 mass % or less of the third component, and the inorganic component is one or more selected from a group consisting of AlO, SiO, CaO, BO, KO, and NaO. A coating layer formed after application solidly adheres to the steel and does not come off in the environment of both cold and hot working.

A pierced shell of an austenitic stainless steel having a good inner surface condition is provided, and a means is established which can perform mass production on an industrial scale of a good quality seamless steel pipe of stainless steel. An austenitic stainless steel billet with a P content of at most 0.040% and an S content of at most 0.020% is pierced under conditions such that the pipe expansion ratio H (outer diameter of shell/diameter of billet to be worked) satisfies the following equation to obtain a tube shell of an austenitic stainless steel. {P(%)/(0.025&#xd7;H&#x2212;0.01)}+{S(%)/(0.015&#xd7;H&#x2212;0.01)}&#x2266;1. When manufacturing a seamless steel pipe of an austenitic stainless steel, the above-described shell is rolled to form a pipe.

Tube shell for manufacturing a seamless steel pipe and a method for its manufacture

By employing a Cr-plated mandrel bar for producing hot seamless tubes according to the present invention wherein centerline average roughness Ra in axial and circumferential directions as well as maximum depth Rv in axial and circumferential directions is specified and further maximum height Rp in axial and circumferential is specified, surface defects such as seizure unlikely generate in an elongation-rolling process by a mandrel mill so that the service life can be dramatically extended, thereby the remarkable reduction of tool cost can be achieved. Moreover, it contributes greatly to improve the inner surface quality of hot seamless tubes to be rolled by a mandrel mill rolling process. Also, the manufacturing method by the present invention makes it possible to efficiently manufacture Cr-plated mandrel bar for producing hot seamless tubes.

Cr-plated mandrel bar for manufacturing hot seamless tube and method of manufacturing the same

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Osaka, Japan

Hirofumi Hori