KR950003456A

KR950003456A - Method of manufacturing 80kgf / mm2 unpainted weathering steel with tensile strength

Info

Publication number: KR950003456A
Application number: KR1019930014766A
Authority: KR
Inventors: 홍순택; 유장용
Original assignee: 조말수; 포항종합제철 주식회사; 백덕현; 재단법인 산업과학기술연구소
Priority date: 1993-07-30
Filing date: 1993-07-30
Publication date: 1995-02-16
Also published as: KR950005926B1

Abstract

본 발명은 빌딩, 철탑 및 교량등의 구조물에 무도장으로 사용되는 내후성 강을 제조하는 방법에 관한 것으로서, 종래의 인장강도 50㎏f/㎜²급 무도장 내후성 강 또는 이 내후성 강에 내후성에 유효한 합금원소들을 적당량 첨가하여 직접 소입 공정을 적용하므로서, 강도 및 충격인성이 우수한 인장강도 80㎏f/㎜²급 무도장 내후성 강을 제공하고자 하는데, 그 목적이 있다.The present invention relates to a method for manufacturing weathering steel used for non-painting in structures such as buildings, steel towers and bridges, the conventional tensile strength 50kgf / mm grade ² unpainted weathering steel or alloy element effective for weathering resistance to this weathering steel By applying an appropriate amount of them to apply a direct hardening process, to provide a tensile strength 80kgf / mm grade ² unpainted weather-resistant steel excellent in strength and impact toughness, the purpose is.

본 발명은 중량%로, C:0.18% 이하, Mn:1.40% 이하, Si:0.15-0.65%, Cr:0.45-0.75%, Cu:0.3-0.50%, Ni:0.05-0.30%, P:350ppm 이하, S:350ppm 이하, 잔부 Fe 및 기타 불가피한 불순물로 조성되는 내후성 강 슬라브 또는 이 내후성 강에 Nb, Mo, Zr, V 및 Ti 중에서 선택된 1종 또는 2종 이상을 총합으로 0.15% 첨가한 강 슬라브를 1150-1300℃의 온도범위에서 가열한 후, 각 압연 패스(pass)당 10-30%의 압하율로 750-1,050℃의 압연 종료 온도까지 연속 열간 압연하고 30초 이내에 5-50℃/sec의 냉각속도로 상온까지 수냉한 다음, AC₁온도 이하인 550-700℃의 온도범위에서 템퍼링하여 인장강도 80㎏f/㎜²급 무도장 내후성 강을 제조하는 방법을 그 요지로 한다.In the present invention, by weight%, C: 0.18% or less, Mn: 1.40% or less, Si: 0.15-0.65%, Cr: 0.45-0.75%, Cu: 0.3-0.50%, Ni: 0.05-0.30%, P: 350 ppm Or less, S: 350 ppm or less, weathering steel slab composed of balance Fe and other unavoidable impurities, or steel slab in which at least one selected from Nb, Mo, Zr, V, and Ti is added 0.15% in total After heating at a temperature range of 1150-1300 ° C, continuously hot rolling to a rolling end temperature of 750-1,050 ° C at a reduction ratio of 10-30% per each rolling pass and within 5-50 ° C / sec within 30 seconds. After cooling to room temperature at a cooling rate of and then tempering at a temperature range of 550-700 ° C. below AC ₁ temperature, a method for producing a tensile strength 80kgf / mm class ² unpainted weathering steel is provided.

Description

Tensile strength 80㎏f / ㎜2 Unpainted weatherproof steel manufacturing method

본 내용은 요부공개 건이므로 전문내용을 수록하지 않았음Since this is an open matter, no full text was included.

Claims

By weight%, C: 0.18% or less, Mn: 1.40% or less, Si: 0.15-0.65%, Cr: 0.45-0.75%, Cu: 0.3-0.50%, Ni: 0.05-0.30%, P: 350 ppm or less, S Weathering steel slab composed of: 350ppm or less, remainder Fe and other unavoidable impurities is heated at a temperature range of 1150-1300 ° C, and then rolled at 750-1,050 ° C with a reduction ratio of 10-30% per each rolling pass. Tensile strength 80kgf /, characterized by continuous hot rolling to the end temperature and water-cooled to room temperature at a cooling rate of 5-50 ° C./sec within 30 seconds, and then tempering at a temperature range of 550-700 ° C. below AC ₁ temperature. ㎜ Class ² Unpainted Weatherproof Steel.

The tensile strength 80kgf / mm class ² uncoated weather resistant steel according to claim 1, wherein 0.15% of one or two or more selected from Nb, Mo, V, Zr and Ti is added to the weathering steel in total. Manufacturing method.

※ Note: The disclosure is based on the initial application.