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Steel product for structural member of automobile and method for production thereof

A technology of automobile structure and manufacturing method, applied in the direction of manufacturing tools, furnaces, heat treatment equipment, etc., can solve the problems that the suspension, chassis parts formability, fatigue characteristics, etc. cannot be obtained

Inactive Publication Date: 2007-01-03
JFE STEEL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in these technologies, there is a problem that the required formability and fatigue characteristics of the suspension and chassis components cannot be obtained.

Method used

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  • Steel product for structural member of automobile and method for production thereof
  • Steel product for structural member of automobile and method for production thereof
  • Steel product for structural member of automobile and method for production thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0120] After reheating the 26 types of steel slabs from A to Z shown in Table 1 to the slab heating temperature shown in Table 3, hot-rolled strips with a thickness of 2.6 mm were produced under the conditions shown in Table 3. steel. The obtained hot-rolled steel strip was subjected to pickling treatment, slitting, roll forming, and electric resistance welding to form a welded steel pipe with an outer diameter of 101.6 mm. Among them, the shrinkage ratios during pipe making are shown in Table 3. In addition, Table 2 shows the value of the hardenability multiple of each element of each steel and its total.

[0121] In addition, from the obtained hot-rolled steel strip, samples for microstructure observation were selected, ground and corroded, observed by SEM (1000 magnifications), photographed, image processed, and ferrite volume fraction and average ferrite volume fraction were measured. The equivalent particle diameter of the body circle and the equivalent particle diamete...

Embodiment 2

[0140] Using the slabs having the compositions of the steel numbers A to D shown in Table 1, hot-rolled steel strips were produced under the hot rolling conditions shown in Table 5. These hot-rolled steel strips were pickled to remove scale, and then electric welded steel pipes were manufactured under the pipe-making conditions shown in Table 5. Part of the hot-rolled strip steel is in a hot-rolled state (with black skin). In addition, a part of the hot-rolled steel strip is subjected to cold rolling-annealing treatment, Zn, and Al surface treatment to manufacture steel pipes. In addition, for some parts, instead of the electric welding pipe, the press-welding method and the roll forming-welding method were used. In addition, some steel pipes were subjected to Zn plating after pipe production. In addition, some of the steel pipes were subjected to temperature shrinkage and heat shrinkage on the obtained steel pipes.

[0141] These steel pipes were used as tubular raw materi...

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Abstract

A method for producing a steel product which comprises providing a steel slab having a chemical composition satisfying C: 0.18 to 0.29 %, Si: 0.06 to 0.45 %, Mn: 0.91 to 1.85 %, P: 0.019 % or less, S: 0.0029% or less, sol.Al: 0.015 to 0.075%, N: 0.0049 % or less, O: 0.0049 % or less, B: 0.0001 to 0.0029 %, Nb: 0.001 to 0.019 %, Ti: 0.001 to 0.029 %, Cr: 0.001 to 0.195 %, Mo: 0.001 to 0.195 %, and 0.4 or more and less than 0.58 of Ceq, and satisfying that the sum (chi) of hardenability multiples according to Grossmann being aware of B is 1.2 or more and less than 1.7, heating the steel slab to 1160 to 1320 DEG C, subjecting the resultant slab to a hot finish rolling having an ending temperature for the finish rolling of 750 to 980 DEG C, annealing the rolled product for a period of 2s or more before winding, and then winding the product up at a temperature of 560 to 740 DEG C, to thereby produce a hot-rolled steel belt which has a structure having an average grain diameter (df) corresponding to a ferrite circle of 1.1 mum or more and less than 12 mum and a ferrite volume percentage (Vf) of 30 to 98 %. A steel pipe is produced by a method comprising using the above hot-rolled steel belt as a material and subjecting it to an electric welding wherein a reduction ratio for width is 8 % or less.

Description

technical field [0001] The present invention relates to a steel material suitable for use in automotive structural parts and a method of manufacturing the same. In particular, it relates to the forming of suspension arms and axle beams, the formability of steel materials supplied as raw materials for quenching, the improvement of fatigue strength after quenching, low-temperature toughness, and delayed fracture resistance. Among them, the steel materials referred to in the present invention include steel strips and steel pipes. Background technique [0002] Patent Document 1 discloses a technique related to a method of manufacturing a hot-rolled steel material for vehicle body reinforcement electric welded steel pipe produced by induction hardening. According to the technology described in Patent Document 1, electric-welded steel pipes for vehicle body reinforcement requiring high strength, such as door impact test rods excellent in shock absorption characteristics and core ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/00C21D9/46C21D8/02C21D8/10C22C38/58
CPCC21D8/10C22C38/02C22C38/26C22C38/002C21D8/0226C22C38/28C22C38/04C22C38/22C22C38/001C22C38/32C22C38/38Y02P10/25
Inventor 丰田俊介坂田敬佐藤昭夫兼子鉉一川口博史
Owner JFE STEEL CORP