National Institute for Materials Science

National Research Institute for Metals

Other

Mitsubishi Heavy Industries Limited

Sumitomo Metal Industries, Inc.

Ishikawajima-harima Heavy Industries Co., Ltd.

Nippon Steel Sumitomo Metal Corporation

Susumu Tsukamoto

Hirosada Irie

Isao Kawaguchi

Hirokazu Okada

Kyoji Tachikawa

Hiroaki Kumakura

Kazumasa Togano

Kazuo Hiraoka

Fujio Abe

Masayuki Kondo

Masaaki Tabuchi

Goro Arakane

Hiroshi Honda

Goro Arkane

Yoshikazu Asai

A welded joint of a tempered martensitic heat resisting steel includes a fine-grained heat affected zone of weldment of a heat resisting steel having a tempered martensite structure which exhibits a creep strength of 90% or more of the creep strength of the base metal thereof. The welded joint is inhibited in the formation of the fine-grained HAZ exhibiting a significantly reduced creep strength.

Welded joint of tempered martensite based heat-resistant steel

In a laser welding method, occurrence of weld defects is effectively prevented, and a high-quality weld joint is provided, and in addition, a wide range of material processes including a laser-using de p-penetration welding technique can be implemented. In keyhole welding using a laser performing output pulse modulation, the welding is conducted in accordance with a frequency conforming to a natural frequency of a metal molten pool.

Laser welding processed

The present invention is to provide a novel laser welding method, capable of preventing formation of a welding defect, and achieving a deep penetration by a low heat input so as to enable formation of a welding structure with a high strength and a high toughness even in the case of welding by a high power laser. A welding operation is executed with a periodical fluctuation adjustment so as to have a base output of 50% or more with respect to a peak output.

Laser welding method

Focusing laser beams are emitted to a gas plasma produced through discharge and a laser thermal plasma, which is independent of the gas plasma and extends coaxially along the laser beams, is produced in a gas flow space.

Laser thermal plasma method

A process for producing a superconducting compound tape or wire material, which comprises irradiating electron beams at an acceleration voltage of 5 to 150 KV on a starting tape or wire material consisting essentially of constituent elements of a superconducting compound, a compound between the constituent elements, and/or an alloy between the constituent elements at a power density, determined on the starting tape or wire material, of 1.times.10.sup.3 to 1.times.10.sup.7 W/cm.sup.2 while the starting tape or wire material is moved at a rate of 1 cm to 10 m/sec relative to the electron beams.

Process for producing superconducting compound tape or wire material by

Growing community of inventors

Ibaraki, Japan

Susumu Tsukamoto