Unlock instant, AI-driven research and patent intelligence for your innovation.

High Strength Hot Rolled Steel Sheet Containing High Mn Content with Excellent Workability and Method for Manufacturing the Same

a hot rolled steel and high content technology, applied in the field of hot rolled steel sheets, can solve the problems of multi-phase steel having a disadvantage in view of formability, high cooling rate required to form martensite, etc., and achieve excellent workability, high strength-elongation balance value, and excellent workability

Inactive Publication Date: 2008-10-02
POHANG IRON & STEEL CO LTD
View PDF4 Cites 29 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0011]As apparent from the above description, the present invention provides a high strength hot rolled steel sheet containing a high Mn content with excellent workability, which has a higher strength-elongation balance value than that of TRIP steel known as having excellent elongation in the art.

Problems solved by technology

However, the dual phase steel has a disadvantage in that a high cooling rate is required to form the martensite at low temperatures.
Furthermore, machining of more complicated components with the steel is required for integration of the components, thereby requiring the steel to have an elongation 30% higher than those for the same strength level.
However, the multi-phase steel has a disadvantage in view of formability due to a low elongation.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

example

[0039]After reheating a steel slab having the composition as shown in Table 1 at 1,200° C. for one hour, the steel slab was subjected to hot rolling at a finish hot rolling temperature of 860° C. Then, after cooling the hot rolled steel sheet to a temperature of 680° C., samples were manufactured using the steel sheet, and measured for strength and elongation, results of which are shown in Table 2.

TABLE 1SampleComposition (wt %)No.CMnSPAlNiCuIS10.4514.90.0030.02———IS20.519.980.0030.021.002.002.00IS30.519.980.0030.021.002.003.00IS40.519.980.0030.021.005.002.00IS50.519.980.0030.022.002.052.00IS60.519.980.0030.023.002.052.00IS70.799.980.0030.021.022.052.00CS10.708.020.0030.021.052.052.00CS20.24.00.0030.020.11——IS: Inventive steelCS: Comparative steel

TABLE 2SampleYSTSUni. ElTot. ElTS × Tot. ElNo.(MPa)(MPa)(%)(%)(MPa %)IS1395.0933.038.237.534987IS2401.7752.331.732.124149IS3497.0793.633.734.827617IS4412.0760.148.957.443630IS5464.9763.541.846.235274IS6519.7768.931.237.228603IS7384.4829.33...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
Temperatureaaaaaaaaaa
Temperatureaaaaaaaaaa
Temperatureaaaaaaaaaa
Login to View More

Abstract

A hot rolled steel sheet used for a bumper reinforceing material or for an impact absorption material in a door of automobiles, and a method for manufacturing the same are disclosed. The steel sheet comprises, by weight%, C: 0.2%˜1%, Mn: 8˜15%, S: 0.05% or less, P: 0.03% or less, and the balance of Fe and other unavoidable impurities. A product of tensile strength and total elongation (TS×ToLEl) of the steel sheet is 24,000 MPa % or more. The method provides a high strength hot rolled steel sheet, which has a high strength-elongation balance value, ensuring excellent workability.

Description

TECHNICAL FIELD [0001]The present invention relates to a hot rolled steel sheet used for a bumper reinforcing material or for an impact absorption material in a door of automobiles. More particularly, the present invention relates to a high strength hot rolled steel sheet containing a high Mn content with high elongation which ensures excellent formability, and to a method for manufacturing the same.BACKGROUND ART [0002]In automobiles, bumper reinforcing materials or impact absorption material inside doors are directly related to safety of passengers upon collision of the automobiles, and generally formed of super strength hot rolled steel sheets having a tensile strength of 780 MPa or more. In recent years, corresponding to gradually increasing regulations for environmental pollution, high strength steel has been increasingly used in the automobiles to increase fuel efficiency, and investigations have progressed more and more for commercial application of the high strength steel ha...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): C22C38/04C21D8/02
CPCC21D6/005C21D8/02C21D8/0205C21D8/04C21D8/0405C21D2211/001C22C38/06C22C38/42C22C38/58
Inventor KIM, SUNG-KYUCHIN, KWANG-GEUNKIM, SEONG-JU
Owner POHANG IRON & STEEL CO LTD