Pohang Iron & Steel Co. Ltd.

Yura Tech Co., Ltd.

Nack Joon Kim

Seok Ki Song

Hyun Joong Kim

Dae Yeol Ohm

Jun Ho Bae

Hyang Jin Koh

Jong Hyun Im

Sung Ho Park

Provided is an ignition plug used for an internal-combustion engine. The ignition plug includes: a center electrode; an insulator disposed outside the center electrode; a metal housing disposed outside the insulator; a ground electrode having an end connected to the metal housing and the other end facing the center electrode; and an electrode tip fixed to one or more of the center electrode and the ground electrode. The electrode tip is made of an alloy of iridium Ir, hafnium Hf, and niobium Nb. Therefore, the ignition plug with the low-cost iridium can have high resistance to prevent an iridium element from oxidizing and vaporizing in high speed driving conditions.

Ignition plug

A method for producing a high strength hot-rolled steel sheet with good formability applicable to automobiles, industrial machines and the like is disclosed. The basic composition of TRIP steel is adjusted wherein Cu is added to improve the strength by precipitation hardening of a fine &egr;&mdash;Cu. Other conditions are controlled to obtain a tensile strength of over 90 kg/mm,with good formability. The steel is composed of 0.15-0.3% by weight of C, 1.5-2.5% by weight of Si, 0.6-1.8% by weight of Mn, 0.02-0.10% by weight of Al, 0.6-2.0% by weight of Cu, 0.6-2.0% by weight of Ni, the balance being Fe and inevitable impurities and has a microstructure of multi-phase structure consisting of ferrite, bainite, and retained austenite, or a granular structure (M-A constituents in bainitic ferrite matrix). The steel is finish rolled at a temperature of 750-880&deg; C., water cooled from a water cooling initiation temperature of 680-740&deg; C. to a water cooling termination temperature of 240&times;(% Mn&plus;% Ni)&minus;140 (&deg; C.) to 540&deg; C., and subsequently coiled at this temperature.

Method for manufacturing high strength and high formability hot-rolled transformation induced plasticity steel containing copper

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Pohang, South Korea

Nack Joon Kim