US3918999A - Method for producing efficienty a high toughness and high tensile strength steel materials - Google Patents

Method for producing efficienty a high toughness and high tensile strength steel materials Download PDF

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US3918999A
US3918999A US406283A US40628373A US3918999A US 3918999 A US3918999 A US 3918999A US 406283 A US406283 A US 406283A US 40628373 A US40628373 A US 40628373A US 3918999 A US3918999 A US 3918999A
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reduction
temperature
slab
rolling
steel
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Hiroshi Sekine
Tadakatsu Maruyama
Katsutoshi Yamada
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Nippon Steel Corp
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Nippon Steel Corp
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling

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  • said hot rolling step comprising giving the slab at least one reduction with reduction amount and temperature to be determined by N VR /H in which R is the roll radius(mm) of the rolling mill.
  • N is the roll rotation (rpm) and H is the Oct. 19. l972 Japan .l 47403991 US. Cl. 148/12 F I t. Cl. 7 F i eld of Search t nowadays 15 slab thckness before the reducnon 10 Claims, 3 Drawing Figures Reduction (1.)
  • the present invention relates to a method for producing steel materials through hot rolling including steel materials which have a thickness of more than 6mm and are used as rolled, and more particularly relates to efficient production of high toughness and high tensile strength steel materials or their intermediate products using Si-Mn steel or Nb-containing steel materials under specific rolling conditions.
  • the slab is heated to a temperature not lower than 1230C and then given a total reduction of more than 50% of the initial thickness of the slab at a temperature not lower than 1 100C, and in the successive rolling, the steel is further given in a temperature range of 850 to 700C a total reduction of not less than 30% of the plate thickness at 850C to finish the rolling.
  • the total reduction at a temperature not higher than lOlC is increased and the finishing rolling is conducted in a temperature range of 900 to 780C and each of the last five reductions is restricted to 5% or more.
  • the above conventional rolling methods have defects that production efficiency is remarkably lowered and considerable product rejects are caused due to shape defects, because the slab heating temperature must be lowered than ordinarily, or the reduction amount in the low temperature range must be increased, or the rolling must be continued down to low temperatures.
  • the slab heating temperature must be lowered than ordinarily, or the reduction amount in the low temperature range must be increased, or the rolling must be continued down to low temperatures.
  • the present invention has established a hot rolling method which can solve the above defects or remarkably alleviate them and which can produce not only high tensile strength steels which can be used as rolled but also any high tensile strength steel obtained through rolling operation.
  • a method for producing efficiently a high toughness and high tensile strength steel which comprises subjecting a low-carbon steel slab or a low-carbon low alloy steel slab to hot rolling comprising heating the slab and giving the slab at least one reduction at a defi- 2 nite reduction temperature and reduction corresponding to N min which R is the radius of the rolling mill, N is the rotating speed (rpm) of the roll and H is the slab thickness (mm) before the reduction.
  • a method for producing efficiently a high toughness and high tensile strength steel which comprises hot rolling a low-carbon steel slab or a low-carbon low alloy steel slab, in which hot rolling the first reduction is started at a temperature of 1 C and lower and at least one reduction under the condition defined by N VR /H as in (A) above is given to the slab.
  • the following steps are preferably added in single or in combination to the above steps;
  • the rolling is done in such a manner that the total reduction from 950C and below to the finish of the rolling is not less than 45% of the slab thickness at 950C, and the rolling is finished in a temperature range from 880C to Ar point of the steel material.
  • the rolling is effected so that the total reduction from 820C to the rolling completion is not less than 20% of the slab thickness at 820C, and the rolling is finished at a temperature range from 800C to the Ar;, point of the steel material.
  • the present inventors have conducted extensive studies on the metallurgical processes during the hot rolling of the Nb-containing steels and Si-Mn steels and during the subsequent cooling thereof and have found that although it is very important for improvement of toughness of the Nb'containing steels and Si-Mn steels to finely recrystallize the austenite beforehand by the high temperature rolling, as disclosed in Japanese patent publication Sho 44-27139, this process can proceed at a temperature about 200C lower than the lower limit temperature disclosed in the above prior art under certain conditions in case of Nb-containing steels for example, and it has been found that the basic condition of the rolling for refining the recrystallized austenite grains is not the total reduction down to the above lower limit temperature disclosed in the prior art, but it is to maintain each reduction higher than a certain definite value determined by various factors.
  • the recrystallization is called as static recrystallization in case when the recrystallization of austenite is completed a certain time after the reduction, the austenite grain size obtained by the dynamic recrystallization is always finer than that obtained by the static re crystallization when reduced under the same combination of the reduction temperature and the strain rate. This has been also discovered by the present inventors.
  • the reason for the limitation of the lower limit of each reduction in the rolling within the specific temperature zone in the present invention is that the present invention aims to positively refine the austenite grains through the dynamic recrystallization or at least through a rapid static recrystallization by each reduction in the above specific temperature range according to the above discovery.
  • the limitation of the temperature range of 1 150 to 980 C for Nb-containing steels and 1 150 to 850C for Si-Mn steels in which the specific reduction is conducted is based on the discovery that the dynamic recrystallization is caused relatively easily even by the reduction schedule hitherto practised in rolling mills if the temperature is higher than 1 150C and a certain refinement of the austenite is attained, and that in case of the Nb-containing steels to which the present invention is applied, the dynamic recrystallization can proceed even by the reduction at 980C at least if certain condition is satisfied, and similarly by the reduction at 850C in case of Si-Mn steels.
  • the reason for defining the case in which the reduction is completely eliminated at temperatures above ll50C is that in the case when high efficiency as a whole including steps prior to the hot rolling is obtained if the hot rolling is done with a relatively thin steel slab or in case when the product thickness is large, or in case when it is necessary to maintain the total reduction at the low temperature zone as defined in the additional feature (1) or (2) of the present invention for obtaining very high toughness, it is necessary to re- 4 prise the total reduction number in order to maintain each reduction between 1l50 and 980C or ll50C and 850C not smaller than the lower limit, and in such a case it is desirable for assuring the toughness to eliminate completely the reduction above ll50C.
  • FIG. 1 and FIG. 3 show the results of extensive rolling experiments seeking for the lower limit reduction for the dynamic recrystallization of the austenite by each reduction between 1 150C and 980C or between 1 150C and 850C in relation to the reduction temperature, the rotating speed of the roll, the roll diameter and the plate thickness before the reduction, and these experiments were conducted on assumption of an ordinary process in which the Nb-containing steel or the Si-Mn steel is given continuous reductions and, the austenite grains are gradually refined.
  • FIG. 2 shows results of experiments for determining the lower limit reduction necessary for the dynamic recrystallization of austenite grains to be caused when the first reduction in the temperature range between l150 and 1050C is given to the Nb-containing steel which has been heated at high temperatures as usually and particularly about 1200C at which the austenite grains remarkably coarsen and cooled without any reduction down to ll50C at all.
  • the lower limit reduction is shown as the function of the various rolling conditions as in FIG. 1.
  • Reasons for the definition that at least one reduction larger than those defined in FIG. 1 and FIG. 2 is given are that when only one reduction most disadvantageous to the refinement of the austenite is given under the condition using a strong rolling mill, recrystallized grains of more than No. 5 of the austenite grain size are obtained and if the production process is conducted thereafter in combination with the desirable steps of l), (2) and (3) a satisfactory fine structure of transformation product can be obtained and satisfactorily high strength and toughness are assured for the final products.
  • Nb-containing steels and Si-Mn steels are described separately because the presence of Nb changes considerably the lower limit reduction for the dynamic recrystallization and the reason for the limitation of the carbon content to 0.30% or less in the steel composition applicable to the present invention is that more than 0.30% carbon remarkably deteriorates weldability of the steel and thus undesirable for the steel which requires rolling operations.
  • Reason for the limitation of the niobium content to 0.15% or less in the steel composition in Nb-containing steels is that if the niobium content is more than 0.15%, it is impossible to prevent the raising the lower limit of the temperature at which the austenite can be recrystallized during the rolling, and thus the conditions defined in FIG.
  • the alloying elements other than carbon and niobium are not specifically limited in the present invention because it has been confirmed through experiments that the above facts are not changed quantitatively when Si, Mn, Ni, Cr, Cu and V are varied substantially.
  • silicon and manganese are dispensable for increasing the strength at low cost, but silicon contents more than 0.70% coarsen the ferrite grains, and manganese contents more than 2.0% cause problems in the steel making process and in connection with weldability.
  • silicon contents more than 0.70% coarsen the ferrite grains, and manganese contents more than 2.0% cause problems in the steel making process and in connection with weldability.
  • the upper limits of these elements are defined as above.
  • any high-tensile steel material to be obtained through hot rolling is included in the scope of the present invention.
  • This is based on the following known facts and newly discovered facts.
  • the structure after cooling is mainly of bainite
  • the finer the austenite before the transformation is the better the toughness of the product is.
  • the steel is left to cool or is cooled at controlled cooling rate after the rolling, reheated, quenched and tempered or normalized, the finer the structure after the hot rolling and the cooling is, the more improved the toughness of the product is.
  • the present invention is based on the completely new discoveries including the results of the quantitative experiments and has been established as a controlled rolling method in which the rolling pass schedule in the high temperature range is controlled, and at least one large reduction is given in the high temperature range. This is completely different from the conventional controlled rolling method in which the rolling pass schedule in the low temperature is controlled.
  • the design is made in such a manner that the austenite recrystallization by the rolling at the specific high temperature range is occupied mainly by the dynamic re crystallization, the considerations to the temperature and the time as disclosed in the Iron and Steel Institute Special Report" for waiting for the slab temperature lowering by stopping the rolling operation in the specific temperature range are not required.
  • the rolling at the high temperatures where the steel material is still soft enough is controlled so as to refine the austenite and to assure the same'level of toughness, while the rolling at low temperature where the steel material becomes hard is alleviated, the waiting time for the slab temperature lowering for the low temperature is saved, thus increasing the production efficiency, reducing the defects such as plate waviness and crowns due to the low temperature rolling, improving the production yield, and making possible to effect the rolling by a relatively light rolling mill.
  • the present invention has advantages that only by incorporating the effects of strain rate into the rolling schedule it is no more necessary to translate with great efforts a successful rolling operation at a specific rolling shop or with a specific plate thickness into a rolling operation of different specification, and it is possible to produce good rolled products only with a minimum plant experiments at a rolling shop having no experience of controlled rolling.
  • the above advantages of the present invention have great industrial significance.
  • the present invention also include the cases in which the recrystallization of the austenite in the above temperature range is not the dynamic recrystallization, that is, the recrystallization is completed a certain time after the reduction.
  • the following alloying elements may be added in addition to C, Mn, and Nb for various purposes in combination with the additional production conditions of l) to (3).
  • the reductions in the high temperature range of l to 980C or 1 150 to 850C are specified, but when the low temperature rollings as specified in (l) and (2) are applied in combination, the strength and toughness can be further improved.
  • the above technical thought has some connection with the rolling type in which the rolling pass schedule in the low temperature range is controlled, but the temperature of 950C or lower for Nb-containing steel or of 820C or lower for Si-Mn steel defined for the total reduction and the temperature of 880C or lower for Nb-containing steel or of 800C or lower for Si-Mn steel defined for the hot rolling completion are high as compared with the conventional arts. Namely, in the present invention, the restrictions in the low temperature range are alleviated as compared with the conventional art for the production of the same steel grades by specifying the high temperature rolling conditions, thus improving the production efficiency and yield.
  • the cooling and the coiling conditions after the rolling as defined in the preferably condition (3) are directed to the case when the structure after the coiling is mainly of ferrite-pearlite. It is known that the intermingling of the bainite into the structure after the transformation is harmful] for the toughness of the steel material, and it has been found that it is effective for the refinement of the ferrite to effect a rapid cooling at the time of the transformation so far as the bainite is not present.
  • the cooling rate of 8C/sec. corresponds to the considerable slow cooling side of the conventional continuous hot rolling, and at such a cooling rate the coiling will be naturally a high temperature coiling.
  • the low temperature coiling enhances the effectiveness of precipitation hardening by Nb, and V. Therefore, with a cooling rate as slow as 8C/sec. the strength is naturally low but excellent toughness is assured.
  • lt is preferable to add 0.01 to 0.70% Si and 0.70 to 2.00% Mn to the Nb-containing steel too, from the necessity of the steel making and for assuring the strength at low cost.
  • Lowering of the carbon is also preferable for assuring the toughness and the weldability, but in case of ferrite-pearlite steels in particular, the increase of the transformation temperature thereby is not desir- 7 able because it reduces the precipitation hardening by Nb, and V, coarsens the ferrite grains and deteriorates the toughness.
  • C Mn Nb Niobium when added with the other elements, is effective to improve the toughness and strength, but should be maintained lower from the point of weldability. It also changes partially the conditions shown in FIG. I through its precipitation of NbN into the austenite. Therefore it is preferable to maintain the nitrogen content not more than 0.010%.
  • not more than 0.08% A1 may be added from the necessity of the steel making, not more than 0.20% V may be added for obtaining desirable strength, not more than 0.005% B may be added for assuring hardenability as required for tempered steels, not more than 1.50% Ni may be added for assuring the toughness.
  • the Nb-containing killed steels A and B which were prepared in a convertor were made into flat slabs of 240mm thickness, heated 1300C, rolled to 82mm thickness by three reductions down to 1150C, subjected to the reduction at three temperatures in combination as shown in Table 3 at a constant reduction as shown in Table 2 using the roll groups specified in Table 2 for the fourth, fifth and sixth reductions, and then further rolled into 9mm thickness by twelve reductions in total, and coiled at 650C.
  • the rolling schedule 1 in Table 3 represents an ordinary rolling with no restriction, and the rolling schedules 2 and 3 in which the temperature was restricted had longer rolling times than the ordinary rolling schedule l by 50 and 90 seconds respectively.
  • Table 3 shows also the values of N V R lH and the lower limit reduction values determined from FIG. 1 for the dynamic recrystallization sought for from the reduction temperatures shown in Table 3.
  • Cu may be added for the corrosion resis- Table 2 tance and the strength
  • not more than 1.00% Cr may be added for the strength and the transformation temperaspefiificationpf Rollins Mill and Reduction Allotment ture
  • not more than 0.20% Ce or misch metal may be Fourth Fifth Sixth added for controlling the shape of sulfides and improv- Reduction Reduction Reduction ing the toughness and workability in the direction per- R0" Radius pendicular to the rolling direction, and not more than (m 57 5 365 (0.15 Nb%) Ti only for Nb-containing steel or not 222:?
  • Speed more than 0.10% Zr may be added for adjusting the Change in Slab shape of sulfides, absorbing N, and restricting the 82/48 48/3 31/245 coarsening of the austenite grains during the reheating. 11,321,221 413 35,1 2
  • Table 1 shows the chemical compositions of the steel materials used in present invention.
  • Table 1 Chemical Compositions of Steel Materials (in weight ings are clear.
  • the rolling schedule 1 satisfies the present invention in its fourth and fifth reductions, but includes the sixth reduction between 1150 and 980C which does not satisfy the present invention and thus is outside the scope of the present invention.
  • the rolling shedules 2 and 3 not only the fourth and fifih reductions satisfy the present invention, but also the sixth reduction is effected at temperatures not higher than 980C and thus no restriction for the reduction is required. Namely the rolling schedules 2 and 3 are within the scope of the present invention. Mechanical properties at the coil center portion of the steel strip thus obtained are shown in Table 4.
  • EXAMPLE 2 The killed steel C containing Nb and V, prepared in a. convertor and having the chemical composition shown in Table l was made into a flat slab of 215mm thickness, heated to l300C, and rolled to. 76mm thickness by three reductions down to 1 150C, subjected to three rolling schedules with the combination of the reduction temperatures and the reductions shown in Table 5, using the roll groups shown in Table 2 for the fourth, fifth and sixth reductions, further rolled to 12.7mm thickness by eleven reductions in total, and coiled at the temperatures shown in Table 5.
  • the rolling schedule 4 in Table 5 represents an ordinary rolling with no restriction.
  • the schedule 5 had a longer rolling time than the ordinary rolling schedule by 60 seconds, and in the rolling schedule 6, waiting time was of 70 seconds provided on the waiting side table between the fourth and the fifth reductions.
  • the figures in the parenthesis in Table 5 represent the lower limit reduction amount for the dynamic recrystallization for each reduction sou ht for from FIG. 1 on the basis of the value of N R /H and the reduction temperatures in the table.
  • the rolling schedule 4 in Table 5 includes the sixth reduction which does not reach the lower limit reduction amount determined from FIG. 1 between ll and 980C, while in the rolling schedules 5 and 6, the fourth and the fifth reductions are over the reduction amounts given by FIG. 1 and yet the sixth reduction is 970C in the schedule 5 and 965C in the schedule 6, both being outside the restricted temperature range.
  • the schedules 5 and 6 are within the scope of the present invention.
  • Table 8 Chemical Composition of Steel D C Si Mn 8 Nb V Specification of Rolling Mill, Rolling Schedule and Lower Limit Reductions for Dynamic Recrystallization
  • the mechanical properties near the coil head portion of thus rolled steel plates are shown at the lowest column in Table 6.
  • the schedule 7 which is within the scope of the present invention gives better material properites that the schedule 5 in spite of the thickness of 12.9mm.
  • This example represents a case where the thickness of slabs introduced to a rolling mill is relatively thin. Even in such a case, a fine structure which gives desired excellent strength and toughness can be obtained by completely eliminating reductions above 1 150C and by increasing enough the amount of the first reduction at temperatures lower than llC. Almost no intermingling of bainite was observed in the rolled structure of the above material.
  • EXAMPLE 4 The killed steel D shown in Table 8 containing Nb and V, which was prepared in a convertor was made into flat slabs of 220mm thickness, heated to l250C, and rolled according to the two rolling schedules shown thus outside the scope of the present invention, but the lower temperature reductions were made at far lower temperatures and the total reduction in the low temperature zone is greater as compared with the schedule 8.
  • a method for efiiciently producing a high toughness and high tensile strength steel material which comprises heating a low-carbon or low-carbon, low-alloy steel slab which contains not more than 0.30% C, and not more than 0.15% Nb, and hot rolling the slab, said hot rolling step comprising giving the slab at least one reduction in an amount not smaller than that shown by each of the curves or the interpolated curves shown in FIG. 1 as determined by the constant N IRJH wherein R is the roll radius (mm) of the rolling mill, N is the roll rotation speed (rpm) and H is the slab thickness before the reduction.
  • a method for producing efficiently a high toughness and high tensile strength steel material which comprises heating a steel slab containing not more than 0.30% C and not more than 0.15% Nb to a temperature required for assuring required strength of the steel slab, and hot rolling the slab, said hot rolling comprising giving the slab between 1 150 and 980C at least one reduction including a reduction conducted at the lowest temperature within the above temperature range with a reduction amount not smaller than that shown by each of the curves or the interpolated curves shown in FIG. 1 in accordance with the constant N V R,,/H as defined in claim I and the reduction temperature.
  • a method for producing efficiently a high toughness and high tensile strength steel material which comprises heating a steel slab containing not more than 0.30% C, not more than 0.70% Si and not more than 2.00% Mn to a temperataure required for assuring required strength of the steel slab, and hot rolling the slab, said hot rolling comprising giving the slab between 1 and 850C at least one reduction including a reduction conducted at the lowest temperature within the above temperature range with a reduction amount not smaller than that shown by each of the curves or the interpolated curves shown in FIG. 3 in accordance with the constant N R /H as defined in claim 1 and the reduction temperature.
  • a method for producing efficiently a high toughness and high tensile strength steel material which comprises heating a steel slab containing not more than 0.30% C, and not more than 0.15% Nb to a temperature required for assuring required strength and hot rolling the steel slab, said hot rolling comprising starting the first reduction at a temperature not higher than 1 150C, giving the slab during the rolling between 1 150 and 980C including the first reduction at least one reduction including the reduction conducted at the lowest temperature within the above temperature range with a reduction amount not smaller than that shown by each of the curves or the interpolated curves shown in FIG. 1 in accordance with the constant N V R /H as defined in claim I and the reduction temperature.
  • a method for producing efficiently a high toughness and high tensile strength steel which comprises heating a steel slab containing not more than 0.30% C and not more than 0.l5% Nb to a temperature not lower than 1200C, hot rolling the slab, said hot rolling comprising starting the first reduction at a temperature not higher than 1150C with a reduction amount not smaller than that shown by each of the curves or the interpolated curves shown in FIG. 2 in accordance with the constant N R IH as defined in claim 1 and the reduction temperature, and conducting subsequent reductions down to 980C including at least one reduction including the reduction at the lowest temperature between 1 150 and 850C with a reduction amount not smaller than that shown by each of the curves or the interpolated curves in P16. 1.
  • a method for producing efficiently a high toughness and high tensile strength steel material which comprises heating a steel slab containing not more than 0.30% C, not more than 0.70% Si, and not more than 2.00% Mn to a temperature required for assuring required strength and hot rolling the steel slab, said hot rolling comprising starting the first reduction at a temperature not higher than 1 150C, giving the slab during the rolling between ll50 and 850C at least one re- 18 duction including the reduction conducted at the lowest temperature within the temperature range with a reduction amount not smaller than that shown by each of the curves or the interpolated curves in FIG. 3 in accordance with the constant N V R /H as defined in claim 1 and the reduction temperature.
  • a method for efficiently producing a high toughness and high tensile strength steel material which comprises heating a low-carbon or low-carbon, low-alloy steel slab which contains not more than 0.30% C, not more than 0.70% Si, and not more than 2.0 Mn, and hot rolling the slab, said hot rolling step comprising giving the slab at least one reduction an an amount not smaller than that shown by each of the curves or the interpolated curves shown in FIG. 3 as determined by the constant N V R /H wherein R, is the roll radius (mm) of the rolling mill, N is the roll rotation speed (rpm) and H is the slab thickness before the reduction.

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US406283A 1972-10-19 1973-10-15 Method for producing efficienty a high toughness and high tensile strength steel materials Expired - Lifetime US3918999A (en)

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Cited By (8)

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Publication number Priority date Publication date Assignee Title
US4011106A (en) * 1975-06-18 1977-03-08 Nippon Steel Corporation Hot-rolled steel sheet of high cold formability and method of producing such steel sheet
US4115155A (en) * 1974-05-03 1978-09-19 Bethlehem Steel Corporation Low carbon high yield and tensile strength steel and method of manufacture
US4119442A (en) * 1975-12-01 1978-10-10 Nippon Steel Corporation Process for manufacturing a steel product
US4397698A (en) * 1979-11-06 1983-08-09 Republic Steel Corporation Method of making as-hot-rolled plate
US4397697A (en) * 1979-12-06 1983-08-09 Stahlwerke Peine-Salzgitter Ag Hot strips or heavy plates from a denitrated steel and method for their manufacture
DE3201204A1 (de) * 1982-01-16 1983-08-11 M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8900 Augsburg "verwendung eines kohlenstoff-mangan-stahles fuer bauteile mit hoher festigkeit und zaehigkeit bei einfacher waermebehandlung"
US5542995A (en) * 1992-02-19 1996-08-06 Reilly; Robert Method of making steel strapping and strip and strapping and strip
US20150203948A1 (en) * 2012-07-31 2015-07-23 Nippon Steel & Sumitomo Metal Corporation Cold rolled steel sheet, electrogalvanized cold-rolled steel sheet, hot-dip galvanized cold-rolled steel sheet, alloyed hot-dip galvanized cold rolled steel sheet, and manufacturing methods of the same

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Publication number Priority date Publication date Assignee Title
JPS5173951A (en) * 1974-12-24 1976-06-26 Nippon Steel Corp Atsukohanno atsuenhoho
DE3320896C1 (de) * 1983-06-09 1984-08-16 Bayerische Motoren Werke AG, 8000 München Steuereinrichtung einer Druckgießmaschine
DE3434743A1 (de) * 1984-09-21 1986-04-03 M.A.N.-B & W Diesel GmbH, 8900 Augsburg Verfahren zur herstellung von stangenfoermigen maschinenteilen
DE3434744A1 (de) * 1984-09-21 1986-04-03 M.A.N.-B & W Diesel GmbH, 8900 Augsburg Verfahren zur herstellung von warmgewalzten stangen
JPH0342632Y2 (fr) * 1985-07-13 1991-09-06

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US3328211A (en) * 1963-12-05 1967-06-27 Ishikawajima Harima Heavy Ind Method of manufacturing weldable, tough and high strength steel for structure members usable in the ashot-state and steel so made
US3645801A (en) * 1968-12-20 1972-02-29 Bethlehem Steel Corp Method of producing rolled steel having high-strength and low-impact transition temperature
US3726723A (en) * 1970-05-11 1973-04-10 American Metal Climax Inc Hot-rolled low alloy steels

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US3328211A (en) * 1963-12-05 1967-06-27 Ishikawajima Harima Heavy Ind Method of manufacturing weldable, tough and high strength steel for structure members usable in the ashot-state and steel so made
US3645801A (en) * 1968-12-20 1972-02-29 Bethlehem Steel Corp Method of producing rolled steel having high-strength and low-impact transition temperature
US3726723A (en) * 1970-05-11 1973-04-10 American Metal Climax Inc Hot-rolled low alloy steels

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4115155A (en) * 1974-05-03 1978-09-19 Bethlehem Steel Corporation Low carbon high yield and tensile strength steel and method of manufacture
US4011106A (en) * 1975-06-18 1977-03-08 Nippon Steel Corporation Hot-rolled steel sheet of high cold formability and method of producing such steel sheet
US4119442A (en) * 1975-12-01 1978-10-10 Nippon Steel Corporation Process for manufacturing a steel product
US4397698A (en) * 1979-11-06 1983-08-09 Republic Steel Corporation Method of making as-hot-rolled plate
US4397697A (en) * 1979-12-06 1983-08-09 Stahlwerke Peine-Salzgitter Ag Hot strips or heavy plates from a denitrated steel and method for their manufacture
DE3201204A1 (de) * 1982-01-16 1983-08-11 M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8900 Augsburg "verwendung eines kohlenstoff-mangan-stahles fuer bauteile mit hoher festigkeit und zaehigkeit bei einfacher waermebehandlung"
US5542995A (en) * 1992-02-19 1996-08-06 Reilly; Robert Method of making steel strapping and strip and strapping and strip
US20150203948A1 (en) * 2012-07-31 2015-07-23 Nippon Steel & Sumitomo Metal Corporation Cold rolled steel sheet, electrogalvanized cold-rolled steel sheet, hot-dip galvanized cold-rolled steel sheet, alloyed hot-dip galvanized cold rolled steel sheet, and manufacturing methods of the same
US9879336B2 (en) * 2012-07-31 2018-01-30 Nippon Steel & Sumitomo Metal Corporation Cold rolled steel sheet, electrogalvanized cold-rolled steel sheet, hot-dip galvanized cold-rolled steel sheet, alloyed hot-dip galvanized cold rolled steel sheet, and manufacturing methods of the same

Also Published As

Publication number Publication date
CA997256A (en) 1976-09-21
JPS4962320A (fr) 1974-06-17
DE2352308A1 (de) 1974-05-02
GB1451963A (en) 1976-10-06
FR2203880A1 (fr) 1974-05-17
FR2203880B1 (fr) 1976-10-01
JPS5324892B2 (fr) 1978-07-24
IT1001598B (it) 1976-04-30

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