Nippon Steel Corporation

The Furukawa Electric Co., Ltd.

Hiroshi Yada

Koe Nakajima

Hirofumi Yoshimura

Yoshikazu Matsumura

Mikio Ogai

Masatoki Nakayama

Jiro Tominaga

Katsuhiro Kawashima

Naoomi Yamada

Yasuo Kimiya

Katsuo Kaku

Hiroshi Nohgata

Saburo Shikoh

Sin-ichi Nisida

Mitsuo Honda

Masaaki Hatta

Method of and apparatus for measuring transformation degree

A high-tension high-toughness steel excellent in resistance to delayed fracture which consists essentially of 0.15 to 0.50% of C, up to 1.50% of Si, 0.20 to 1.50% of Mn, up to 2.00% of Cr, 0.0005 to 0.0030% of B, 0.005 to 0.10% of acid-soluble Al, up to 0.010% of P, up to 0.0020% of N, 0.010 to 0.050% of Ti and the balance iron and inevitable impurities, and has a tempered martensitic structure obtained by quenching and tempering.

High-tension high-toughness steel having excellent resistance to delayed

A novel hot-rolled ferritic steel composed of 70% or more of equiaxed ferrite grains having an ultra-fine grain size of 4 .mu.m or less. This steel is produced by a hot working at approximately the Ar.sub.3 point and by one or more passes of the hot working having a total reduction ratio of at least 75%. When a plurality of passes is carried out, the time between passes is less than one second. Due to hot working, dynamic transformation of austenite and/or dynamic recrystallization of ferrite takes place. The total reduction ratio may be at least 35% for a high purity steel.

Ferritic steel having ultra-fine grains and a method for producing the

A low temperature high strength tough steel is provided by effecting a series of heat treatments at predetermined temperatures. The steel comprises C, Si, Mn, Ni, Mo, Nb, N, Al, and if necessary, V, Ti, Cr, Ca or Ce in predetermined amounts with the rest iron and unavoidable impurities.

Method for producing a low temperature high strength tough steel

A hollow precision-machined body, such as a circular waveguide for transmission of millimeter wavelengths, is welded to a metallic body with minimum distortion of the precision body, by directing a concentrated beam of heat-producing energy such as an electron beam or a laser beam or a plasma across and peripherally about the interface between the precision and metallic bodies to produce a bead whose width at the contact area is related to the clearance between the bead and the inner surface of the precision tube and the maximum allowable strain at the inner face of the precision tube. Alternately, the energy beam is directed along the interface and around the periphery thereof to produce a bead whose depth of penetration is related to the thickness of the precision body and the maximum permissible strain at the inner surface of the precision body.

Method for welding between metallic body and precision tube body

Growing community of inventors

Kitakyushu, Japan

Hiroshi Yada