JPS5816026A - Production of good workable steel material - Google Patents

Abstract

PURPOSE:To produce good workable steel which prevents flange cracking by subjecting a slab made of steel contg. specific contents of c, Mn, Al to heating and extracting at specific temp. then to hot rolling. CONSTITUTION:This relates to production of steel materials for cans wherein a slab made of the steel contg. at least <=0.10% C, <=0.6% Mn, and 0.02-0.2% Al is subjected to heating and extracting at <=1,080 deg.C, more preferably <=1,050 deg.C. Thereafter, it is subjected to ordinary hot rolling. Then, black inclusions which are cause for flange cracking are reduced considerably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a steel material with good workability, and particularly to a method of manufacturing a can porcelain material.

The steel materials used for cans for carbonated drinks, etc. are used in cupping,
It undergoes the most rigorous processing consisting of trowing, ioning, and flanging. In particular, since it is desired that there be virtually no flange processing cracks, there is a demand for ultra-clean steel materials with very few non-metallic inclusions that cause such cracks.

However, in manufacturing the above steel materials, the slab used may be made by either the steel ingot method, the continuous casting method ψ;
, its components are generally C≦0.10% in order to meet the above strict demands and maintain good processability.

Mn≦0.6%, and the range of At is set at the upper limit of At.
In order to avoid the effect of hardening due to N, the lower limit value is 0.0 because sufficient deoxidation is required to obtain a highly clean steel material.
The content should be between 2% and 0.2%.

However, the reality is that it has not been possible to manufacture a steel material that can substantially eliminate the above-mentioned problems.

By the way, the present inventors conducted an investigation into the cause of 17-lunge processing cracks in order to manufacture a steel material with virtually no 7-lunge processing cracks, and first, the steel material was subjected to strict processing at the tin plate stage. Magnetic particle flaw detection, which is generally used as a criterion for determining the presence or absence of oxidation, was conducted.

The results are shown in Table 1. As is clear from this table, most of the causes of flange cracking are explained in detail in the section below 50μ.

Table 2 shows the chemical composition percentage of the slab used as the test material in this example, the heating extraction temperature, the number of black inclusions of 50μ or more, and the evaluation of the magnetic detection results.

As is clear from Table 2, the AI of the present invention example is 2°3.6
．． '/, 11. U2 has less than 15 black inclusions and has reached the magnetic probe pass level that is determined to be substantially harmless, but comparative examples A4, 5, 8, 9°10.13.1
4.15 had 15 or more black inclusions, which was a failure level that could not be put to practical use with a magnetic probe.

Evaluation ◎・・・ ・・ (Excellent) Number of magnetic probe defects per 1♂ tin plate ~ 0.2 (DI/nr ○・・ ・ ・ ・ (Good) 〃 ~ 0.4〃×・
...(Not allowed) tt 0.4 In the present invention described above, a slab that may generate black inclusions is heated to 1050°C to 1080°C or less and then rolled, so black inclusions are eliminated at the product stage. As a result, erroneous detection by magnetic detectors of inclusions that do not cause flange cracking can be reduced to virtually zero. Therefore, the yield is increased but the cost is decreased, and furthermore, since heating in hot rolling is performed at a low temperature, steel materials can be manufactured in an energy-saving manner, which has a great industrial effect.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between the heating temperature of the slab and the number of black inclusions present in the hot rolled sheet, and Figures 2 (a) and (b) are 50
The figure showing the composition ratio of inclusions larger than μ by process. FIG. 3 is a diagram showing the relationship between each process and the number of inclusions. Applicant Nippon Steel Corporation Building 3IIA C41 Inventory A2-0 06111tt@Al-Ca-0

Claims (1)

[Claims] At least C≦0.10%, Mn≦0.6%r At
A steel material with good workability, characterized in that a slab made from steel containing 0.0102 to 0.2% is heated and extracted at a temperature of 1080°C or lower, preferably 1050°C or lower, and then subjected to normal hot rolling. manufacturing method.