US3590476A - Method for producing a tellurium steel article - Google Patents

Method for producing a tellurium steel article Download PDF

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Publication number
US3590476A
US3590476A US802798*A US3590476DA US3590476A US 3590476 A US3590476 A US 3590476A US 3590476D A US3590476D A US 3590476DA US 3590476 A US3590476 A US 3590476A
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Prior art keywords
tellurium
steel
molten steel
ingot mold
ingot
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US802798*A
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English (en)
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Bernard S Levy
Gary W Henger
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Inland Steel Co
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Inland Steel Co
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D7/00—Casting ingots, e.g. from ferrous metals
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/4998—Combined manufacture including applying or shaping of fluent material
    • Y10T29/49988—Metal casting
    • Y10T29/49991—Combined with rolling

Definitions

  • the present invention relates to hot rolled tellurium steel articles which are free of surface checking and to methods for producing such articles.
  • an ingot has its cross section reduced to form a succession of intermediate articles, such as billets or blooms, having a polygonal cross section; and these intermediate articles are in turn hot rolled to a reduced cross section, the final article usually being a bar.
  • the machinability of steel is improved by adding tellurium thereto.
  • tellurium steel there is a tendency for the steel-to develop a surface defect known as surface checking. This is manifest by a large number of small cracks at the surface of the steel article, particularly along the 'come'rs. Severe surface checking renders the article commercially unacceptable.
  • a tellurium steel article produced in accordance with the present invention has a surface which is relatively devoid of surface checking.
  • the article has an interior with arelatively substantial amount of tellurium dispersed throughout and a skin which is relatively devoid of tellurium.
  • the article is a steel bar which is both readily machinable and readily extrudable.
  • the machinability of the bar is due to the tellurium content thereof and the extrudability is enhanced by relatively low sulfur, carbon and manganese contents in the bar and because the skin of the bar consists essentially of relatively pure iron.
  • a method in accordance with the present invention comprises filling at least the greater portion of an ingot mold with molten steel not containing tellurium, permitting a solid steel skin to form on at least the sides of the ingot mold and then introducing tellurium into the molten interior of the steel and dispersing the tellurium therein. After the entire ingot has solidified, it has an interior with a relatively substantial amount of tellurium dispersed throughout and a skin relatively devoid of tellurium.
  • the resulting hot rolled article of reduced cross section has an interior with a relatively substantial amount of tellurium dispersed throughout and a skin relatively devoid of tellurium. Because of the manner in which the tellurium is distributed throughout the cross section of the article undergoing hot rolling, surface checking during hot rolling is minimized or avoided.
  • FIG. 1 is a graph illustrating the distribution of tellurium throughout the cross section of a tellurium steel article such as a bloom;
  • FIG. 3 is a vertical sectional view of an ingot mold in which a nonrimming steel is undergoing solidification
  • FIG. 2 there is illustrated an ingot mold 10 filled with a rimming steel having a composition typically consisting essentially of, in wt. percent:
  • Iron balance lngot mold 10 is of conventional size and construction, having a base 27% inches square and tapering slightly towards the top.
  • the pouring temperature for the molten steel is typically in the range 2875-2900 F.
  • Rimming is allowed to occur within mold 10 until a solid steel skin 11 forms on at least the sides of the ingot mold, as well as on the bottom thereof in the embodiment illustrated in FIG. 2.
  • Skin 11 is substantially devoid of metalloids and consists essentially of pure iron.
  • tellurium is added to the molten interior 12 of the ingot.
  • the tellurium may be in bar form or in the form of pellets or shot and is added downwardly through the top 14 of the unsolidified molten steel.
  • Internal agitation is inherent in rimming steel, and this agitation is indicated by arrow lines 13. This internal agitation helps disperse the tellurium throughout the ingot's molten interior 12.
  • the average tellurium content of the solidified ingot interior, and of articles rolled from said ingot, is typically in the range 0.030.2 wt. percent.
  • ingot mold 10 is stripped therefrom, and the ingot is subjected to conventional hot rolling procedures to reduce the cross section of the ingot through various intermediate stages, including a bloom stage and a billet stage, to a finished article 15 having a round cross section, as illustrated in FIG. 4.
  • the resulting steel article 15 has an interior 16 throughout which is dispersed a relatively substantial amount of tellurium, illustrated exaggeratively at 17, and has a skin 18 relatively devoid of tellurium. Skin 18 is exaggerated in FIGS. 4 and 5, and is not intended to represent a rim zone.
  • FIG. 1 illustrates the relative distribution or dispersion of tellurium throughout the cross section of a steel article produced in accordance with the present invention.
  • the particular article depicted in the diagram of FIG. 1 is a bloom having an I I inch width.
  • the tellurium content increases from the surface of the article to the center thereof, indicated by the 5% inch mark on the abscissa of the graph.
  • Lines 20, 21 represent two examples of the relative distribution of tellurium along the cross section of the article between the surface and the center thereof. The actual percentage of tellurium at any location along the cross section would depend upon the amount of tellurium added to the ingot.
  • the relative amount of tellurium at a given location typically may be anywhere between lines 20 and 21; and the position of lines 20, 21 with respect to each other, and the shape of line 21, can vary depending upon the part of the ingot from which the cross section in question is rolled. For example, if the cross section in question is rolled from the center of the ingot, the tellurium distribution typically will be somewhere between lines 20 and 21 as shown on FlG. 1; whereas, if the cross section in question is rolled from the bottom of the ingot, the lower line 21 could be further below line 20 than in FIG. 1.
  • the abrupt rise, at 22 in line 21, could also be substantially more gradual.
  • the tellurium is added no earlier than one minute after the ingot mold has been filled with the molten steel, and preferably the tellurium is added at a time between two minutes and five minutes after the ingot mold has been filled with molten steel.
  • the minimum delay between the filling of the ingot mold and the addition of tellurium can be determined by the presence or absence of surface checking during hot rolling. If surface checking arises during hot rolling, this is an indication that not enough time has been allowed to elapse between the filling of the ingot mold and the addition of the tellurium. That is, not enough time has been allowed for a solid skin, devoid of tellurium, to form. Increasing the delay between the filling of the ingot mold and the addition of tellurium will overcome this problem.
  • the relatively low carbon content (0.030.l wt. percent) improves the ductility of the steel bar, and the relatively low sulfur content (0.025 wt. percent max.) improves the plasticity of the steel bar, both enhancing the extrudability of the steel bar.
  • the low sulfur content permits a lower manganese content (0.25O.6O wt. percent) then would normally be possible if the sulfur content were high. (A relatively high sulfur content requires a correspondingly high manganese content to offset hot shortness normally caused by sulfur).
  • the lower manganese content permits the steel to rim.
  • the skin of the steel consists essentially of relatively pure iron which is more ductile than a skin containing substantial amounts of metalloids, and the ductile skin enhances the extrudability of the bar.
  • the sulfur content is relatively low, the drop in machinability otherwise resulting from a reduced sulfur content is offset by the tellurium content of the steel (0.03-0.2 wt. percent).
  • a bar having the composition referred to in the preceding paragraph is the preferred embodiment from the standpoint of extrudability and machinability.
  • Permissible compositions of an extrudable, machinable bar 15, in accordance with the present invention could fall within the following ranges of elements, in wt. percent:
  • FIG. 3 An embodiment using a nonrimming steel is illustrated in FIG. 3.
  • An ingot mold 30 is filled about 85-90 percent full with molten steel not containing tellurium.
  • a typical composition for such a non rimming steel would be as follows, in wt. percent:
  • lron balance lngot mold 30 is partially filled to level 33, and a solid skin 31 is allowed to form on at least the sides of the mold and, as shown in H6. 3, also along the bottom.
  • the empty uppermost mold portion 34 is filled with molten steel, and tellurium is added to the ingot mold at the same time.
  • tellurium can be thrown into a descending stream of molten steel and the action of the descending stream of molten steel will disperse the tellurium throughout the molten ingot interior 32.
  • the average tellurium composition of an article rolled from the ingot would be in the range 0.03-0.20 wt. percent.
  • Another method of producing an article from a nonrimming steel is to fill the ingot mold, as in FlG. 2, allow a solid skin to form along at least the sides of the ingot mold, and then introduce the tellurium into the interior of the steel by mechanically propelling it downwardly into the ingot mold and then stirring the molten interior mechanically or with compressed inert gas.
  • ingot mold 30 can be provided with a conventional hot top.
  • An article produced from nonrimming steel in accordance with the methods described above, will have a tellurium dispersion similar to that illustrated in FlG. 1, and will have a cross section similar to that illustrated in F I05. 4 and 5. Because the hot rolled article composed of nonrimming steel is relatively devoid of tellurium in the skin thereof, surface checking during hot rolling of the article is minimized.
  • the present invention is not limited to rimming steels and nonrimming steels nor to the specific compositions of tellurium steel set forth above.
  • other molten steel base compositions to which tellurium (e.g., 0.03-0.2 wt. percent) may be added include the conventional A.l.S.l. 1000, 1,100 and l,200 series of carbon steels having the following respective typical wt. percent ranges of elements:
  • tellurium e.g. 0.03- 0.20 wt. percent
  • a molten base steel composition after a solid steel skin has formed on at least the sides of the ingot mold thereby enabling the production of a hot rolled steelarticle having an interior with a relatively substantial amount of tellurium and a skin relatively devoid of tellurium and substantially free of surface checking, i.e., free of such surface checking as would render the article commercially unacceptable.
  • machinability increasing elements may also be added to the steel. These include lead, added in the conventional manner; and typical compositions containing both tellurium and lead are disclosed in Holowaty U.S. Pat. No. 3,152,889. Selenium may be used interchangeably with tellurium and is added in the same way as tellurium, i.e., into the molten base steel composition after a solid steel skin has formed on at least the sides of the ingot mold.
  • a method for reducing surface checking of telluriumcontaining steel during hot rolling comprising the steps of:
  • the delay between said filling step and said tellurium-introducing step is sufficient to assure that said hot rolled article of reduced cross section has a skin relatively devoid of tellurium.
  • said molten steel has a rimming composition
  • said molten steel is allowed to rim in said ingot mold
  • said tellurium is introduced while said molten steel is rimming;
  • tellurium being dispersed into the interior of the molten steel in the ingot mold by the action of the addition of said minor portion of molten steel.
  • said tellurium is introduced into the interior of the molten steel in the ingot mold by propelling the tellurium downwardly into the ingot mold;
  • said tellurium is introduced into the interior of the molten steel no earlier than one minute after at least said greater portion of the ingot mold has been filled with said molten steel.
  • said tellurium is introduced at a time between 2 and 5 minutes after at least said greater portion of the ingot mold has been filled.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Metal Rolling (AREA)
  • Heat Treatment Of Steel (AREA)
US802798*A 1969-02-27 1969-02-27 Method for producing a tellurium steel article Expired - Lifetime US3590476A (en)

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US80279869A 1969-02-27 1969-02-27

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US (1) US3590476A (ja)
JP (1) JPS5210806B1 (ja)
AT (1) AT314575B (ja)
BE (1) BE746367A (ja)
CH (1) CH509845A (ja)
DE (1) DE2006477A1 (ja)
DK (1) DK136203B (ja)
ES (1) ES376977A1 (ja)
FR (1) FR2032464B1 (ja)
GB (1) GB1302065A (ja)
LU (1) LU60412A1 (ja)
NL (1) NL153104B (ja)
NO (1) NO137776C (ja)
SE (1) SE352546B (ja)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2937908A1 (de) * 1978-09-20 1980-04-03 Daido Steel Co Ltd Te-s-automatenstahl mit niedriger anisotropie und verfahren zu seiner herstellung
DE3009491A1 (de) * 1979-03-14 1980-09-25 Daido Steel Co Ltd Stahl fuer das kaltschmieden und verfahren zu seiner herstellung
EP0045815A1 (en) * 1980-08-11 1982-02-17 Inland Steel Company Semi-finished steel article and method for producing same
US4348800A (en) * 1980-04-14 1982-09-14 Republic Steel Corporation Production of steel products with medium to high contents of carbon and manganese and superior surface quality
US4405381A (en) * 1980-02-15 1983-09-20 Republic Steel Corporation Steel products such as bars, compositionally non-rimming and internally aluminum killed, having good surface condition
US4411056A (en) * 1980-04-14 1983-10-25 Republic Steel Corporation Production of steel products with medium to high contents of carbon and manganese and superior surface quality

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2187415A (en) * 1939-05-13 1940-01-16 Mackintosh Hemphill Company Method of making rolls
US2979793A (en) * 1958-05-08 1961-04-18 American Brake Shoe Co Cast iron
US3414042A (en) * 1966-05-12 1968-12-03 Behrens Knut Franz Methods of producing killed steel

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2187415A (en) * 1939-05-13 1940-01-16 Mackintosh Hemphill Company Method of making rolls
US2979793A (en) * 1958-05-08 1961-04-18 American Brake Shoe Co Cast iron
US3414042A (en) * 1966-05-12 1968-12-03 Behrens Knut Franz Methods of producing killed steel

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2937908A1 (de) * 1978-09-20 1980-04-03 Daido Steel Co Ltd Te-s-automatenstahl mit niedriger anisotropie und verfahren zu seiner herstellung
DE3009491A1 (de) * 1979-03-14 1980-09-25 Daido Steel Co Ltd Stahl fuer das kaltschmieden und verfahren zu seiner herstellung
US4405381A (en) * 1980-02-15 1983-09-20 Republic Steel Corporation Steel products such as bars, compositionally non-rimming and internally aluminum killed, having good surface condition
US4348800A (en) * 1980-04-14 1982-09-14 Republic Steel Corporation Production of steel products with medium to high contents of carbon and manganese and superior surface quality
US4411056A (en) * 1980-04-14 1983-10-25 Republic Steel Corporation Production of steel products with medium to high contents of carbon and manganese and superior surface quality
EP0045815A1 (en) * 1980-08-11 1982-02-17 Inland Steel Company Semi-finished steel article and method for producing same

Also Published As

Publication number Publication date
LU60412A1 (ja) 1970-04-28
DK136203C (ja) 1978-02-27
FR2032464B1 (ja) 1974-09-20
CH509845A (fr) 1971-07-15
JPS5210806B1 (ja) 1977-03-26
AT314575B (de) 1974-04-10
DK136203B (da) 1977-09-05
SE352546B (ja) 1973-01-08
GB1302065A (ja) 1973-01-04
BE746367A (fr) 1970-07-31
DE2006477A1 (de) 1970-09-17
ES376977A1 (es) 1972-05-01
FR2032464A1 (ja) 1970-11-27
NL7002684A (ja) 1970-08-31
NO137776C (no) 1978-04-26
NO137776B (no) 1978-01-16
NL153104B (nl) 1977-05-16

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