US3816720A - Process for the decarburization of molten metal - Google Patents

Process for the decarburization of molten metal Download PDF

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Publication number
US3816720A
US3816720A US00194454A US19445471A US3816720A US 3816720 A US3816720 A US 3816720A US 00194454 A US00194454 A US 00194454A US 19445471 A US19445471 A US 19445471A US 3816720 A US3816720 A US 3816720A
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partial pressure
carbon
temperature
composition
carbon monoxide
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US00194454A
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R Hard
U Malhotra
E Bauer
R Dokken
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Union Carbide Industrial Gases Technology Corp
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Union Carbide Corp
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Priority to US00194454A priority Critical patent/US3816720A/en
Priority to CA154,770A priority patent/CA975565A/en
Priority to DE2253480A priority patent/DE2253480C3/de
Priority to SE7214068A priority patent/SE413780B/sv
Priority to FR7238636A priority patent/FR2161942B1/fr
Priority to AT927772A priority patent/AT339938B/de
Priority to BR007623/72A priority patent/BR7207623D0/pt
Priority to IT53748/72A priority patent/IT966875B/it
Priority to ES408142A priority patent/ES408142A1/es
Priority to AU48332/72A priority patent/AU478886B2/en
Priority to JP47108572A priority patent/JPS5226212B2/ja
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Publication of US3816720A publication Critical patent/US3816720A/en
Assigned to MORGAN GUARANTY TRUST COMPANY OF NEW YORK, AND MORGAN BANK ( DELAWARE ) AS COLLATERAL ( AGENTS ) SEE RECORD FOR THE REMAINING ASSIGNEES. reassignment MORGAN GUARANTY TRUST COMPANY OF NEW YORK, AND MORGAN BANK ( DELAWARE ) AS COLLATERAL ( AGENTS ) SEE RECORD FOR THE REMAINING ASSIGNEES. MORTGAGE (SEE DOCUMENT FOR DETAILS). Assignors: STP CORPORATION, A CORP. OF DE.,, UNION CARBIDE AGRICULTURAL PRODUCTS CO., INC., A CORP. OF PA.,, UNION CARBIDE CORPORATION, A CORP.,, UNION CARBIDE EUROPE S.A., A SWISS CORP.
Assigned to UNION CARBIDE CORPORATION, reassignment UNION CARBIDE CORPORATION, RELEASED BY SECURED PARTY (SEE DOCUMENT FOR DETAILS). Assignors: MORGAN BANK (DELAWARE) AS COLLATERAL AGENT
Assigned to UNION CARBIDE INDUSTRIAL GASES TECHNOLOGY CORPORATION, A CORP. OF DE. reassignment UNION CARBIDE INDUSTRIAL GASES TECHNOLOGY CORPORATION, A CORP. OF DE. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: UNION CARBIDE INDUSTRIAL GASES INC.
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/068—Decarburising

Definitions

  • FIG. 2 a EDWIN F. BAUER ROBERT A.HARD ROGER N. DOKKEN UMESH K.MAL. TRA
  • the limit to which the temperature may be elevated is based upon both practical and economic considerations relating to the effect of high temperatures on the life of the vessel lining as well as on the life of the tuyeres which are necessary for injecting the oxygen and inert gas directly into the melt from beneath its surface.
  • dilution of the blowing oxygen with inert gas also involves exonomic considerations since it decreases the rate of steel production in proportion to the percent volume of inert gas introduced, not to mention the cost of the inert gas itself, which can be substantial.
  • the process of the present invention is based on the theoretical assumption that for any small interval of tor, readjustments may be made in the dilution ratio to optimize the process.
  • the mathematical model simulates the complicated natural processes occuring in the refractory lined vessel in terms of the reaction thermodynamics, heat and mass balances and thus predicts the process of a heat.
  • the mathematical calculations may be made by a person; in practice, it could not be done quickly enough to be useful, and therefore the present process requires a computer for its practical implementation.
  • the present invention is a method for refining steel by controlling the decarburization of a predetermined mass of molten metal comprising carbon and iron contained within a refractory lined vessel having means for injecting oxygen and a diluting gas into the mass and adjustable gas flow control means for varying the flow rate of the gases; wherein the process comprises:
  • step (9) resetting the adjustable gas flow control means in accordance with the indication provided in step (9) d. repeating the sequence from step (1) at predetermined time intervals of less than 2 minutes until the carbon content indicated in step (7) has at least decreased to a predetermined level.
  • FIG. 1 is a general schematic diagram of a decarburization system which utilizes the present invention
  • FIGS. 2 and 2a combined represent the logic diagram of the preferred program for carrying out the present invention
  • FIG. 3 is a graph, empirically established which defines the factor F for that portion of the refractory lined vessel which participates in the heat capacity of the system;
  • FIG. 4 is a graph showing the steady state temperature loss in the bath as a function of the size of the bath
  • FIG. 5 is a graph, empirically established, which defines an acceptable band of bath temperature values for corresponding carbon contents.
  • FIG. 6 is a graph, empirically established, showing an alternative acceptable temperature range for corresponding carbon levels in the bath.
  • FIG. 7 is a simplified logic diagram of the preferred program shown in FIGS. 2 and 2a illustrating an alternative embodiment for changing the dilution ratio of oxygen in response to satisfying a given one of a number of different criteria.
  • FIG. 1 Shown diagrammatically in FIG. 1 is a simplified refining system for decarburizing steel consisting of a refractory lined refining vessel 10 charged with a predetermined mass of molten metal 12.
  • the starting composition of the mass may represent essentially iron and carbon where the refined end product is to be a low carbon iron.
  • the starting composition for a stainless steel may be composed essentially of iron, carbon and chromium with nickel in some cases and with additional minor alloying constituents such as, for example, silicon and manganese.
  • the starting composition may be composed essentially of carbon, iron, nickel. chromium, molybdenum and niobium. This invention is not to be construed as limited to any specific steel starting composition nor is the original percentage of any ingredient critical to the invention.
  • Oxygen is passed from a source (not shown) through an oxygen flow control 18 which regulates the flow rate of oxygen before injection into vessel 10.
  • a diluting inert gas is passed from a separate source (not shown) through a flow control 20 which regulates the flow of inert gas.
  • the gas flow controls 18 and 20 respectively are conventional controllers which may be either automatically or manually operated as will as explained hereafter.
  • the gases are combined in the mixing valve 16 and injected directly into the melt l2 preferably through a tuyere assembly 14.
  • Other suitable gas injectors may be employed such as ceramic tubes, conduits, nozzles and the like so long as such means can withstand the bath temperatures involved without introducing undesirable contaminants.
  • Separate means may be used to control pressure in the respective flow lines.
  • the diluting gas may be any gas inert with respect to decarburization and preferably one selected from the group consisting of helium, neon, argon, krypton and xenon, or mixtures thereof. Nitrogen may also be used but with caution because of possible side effects. Argon is the most preferred gas.
  • the production rate as measured by the time required for decarburization is primarily affected by the temperature and gas flow rates and may be maximized by blowing the heat at the maximum total gas flow rate obtainable for the refining vessel and heat size, which is roughly 1,000 to 2,000 cubic feet per hour of total gas flow per ton of metal refining capacity for the vessel, and by keeping the flow rate of oxygen high relative to the flow rate of inert gas until the refractory is threatened by high temperature or until oxidation of the constituents in the melt other than carbon exceed predetermined levels.
  • the temperature must also be kept above a minimum allowable temperature so that the heat can be finished, tapped and teemed into ingot molds without danger of solidifying prematurely.
  • the present invention does not contemplate the use of temperature control elements or devices.
  • Increases in temperature are due to the oxidation reactions occurring in the bath whereas reductions in temperature are due to absorption of heat by the applied inert gas, bath additions, and from the steady state heat loss occurring as a function of bath size, the heat capacity of the refractory and the vessel surroundings.
  • the computer 22 is a general purpose computer which is programmed to operate in accordance with the logic diagram of FIGS. 2 and 2a representing the preferred embodiment of the present invention. Any programmer skilled in such art can rapidly prepare a computer program in the language receptive to the computer utilized to operate in accordance with such logic diagram. In order to carry out the program the computer 22 must have stored in memory data representative of the mathematical equations taught herein as well as data representative of Appendixes A, B, and C and FIGS. 3, 4, and 5 or 6 respectively.
  • the only input information necessary for any given heat is the starting metal composition, temperature, metal weight, the selected initial oxygen and inert gas flow rates and the final desired carbon content. From steelmaking experience it is known that an oxygen flow rate more than ten times greater than the inert gas flow rate will be harmful to the vessel tuyere assem bly 14. Hence, as a practical matter the initial oxygen to inert gas flow rate should be less than 10 1.
  • the computer 22 calculates a plurality of coefficients that define the thermodynamic activities of each constituent element in the bath as a function of the composition of the bath. Employing such coefficients the computer 22 calculates the carbon monoxide partial pressure in equilibrium with carbon and the various metallic elements and their oxides. The reaction which produces the lowest equilibrium partial pressure of carbon monoxide is assumed to be favored and to proceed for some small increment of time. This increment of time is approximated for purposes of the present invention to be a period necessarily greater than zero but less than 2 minutes with a preferred range of between 3 to 30 seconds.
  • the computer 22 without feedback can provide updated simulated sampling of the progress of a heat to determine whether and to what extend readjustment is to be made in the dilution ratio of oxygen and inert gas. The new conditions determined by the computer are automatically fed into memory and used in place of the previous conditions for the next iteration.
  • M is any metallic element in the bath l2such as Fe, Cr, Mn, Si, etc; C is Carbon: O is Oxygen and x and y are integers which represent the chemical formula of the metallic oxide in question.
  • the general chemical reaction represents reactions involving, for example, silicon, manganese, chromium, iron, nickel and/or other metallics which may be present in the mass.
  • the appropriate equilibrium constants are calculated for each reaction in accordance with the above equation using the data from Appendix A as shown below.
  • the computer is programmed as shown in the logic diagram of FIG. 2 to select the lowest theoretical equilibrium partial pressure of carbon monoxide from which the computer then calculates the amount of carbon oxidized if all of the oxygen burns carbon and if not then the amount of carbon and metal oxidized. This is done by comparing the equilibrium partial pressure of CO with that which would be generated if all the oxygen burned carbon.
  • Equation (1) the amount of carbon burned is calculated directly from Equation (1) as follows:
  • the amount of metal oxidized is subtracted from the original total metal weight and the total weight of the oxide resulting is added to the slag.
  • the weight of the carbon oxidized is also substracted from the original metal mass and new composition percentages are calculated.
  • the new composition and weight are stored in memory and used in place of the old composition and weight at the start of the next cycle.
  • thermodynamics In order to establish the most favored of all the possible reactions from thermodynamics, the temperature must be known.
  • the heat generated or absorbed by the reactions is determined from thermodynamic data and from the heat of reactions given in Appendix C shown below. These are translated into temperature by dividing them by the combined heat capacities of the metal, the vessel and-the slag.
  • the heat capacity of the vessel (mainly the refractory) is taken to be Where: W, total working lining refractory weight in pounds and F empirical factor for the portion of the refractory lining which participates in the heat capacity of the system.
  • the heat capacity of the slag is taken to be 0.55 W, lb. cal/C Where: W, slag weight in pounds.
  • W slag weight in pounds.
  • the factor F has been determined by trial and error methods of comparing actual heat data with program results. This factor is shown in FIG. 3 indicating the proper value to be used as a function of refractory weight.
  • the refractory lining weight is known from the vessel design and the metal and slag weights are calculated at the end of each time interval.
  • the steady state heat loss of the system due to its surroundings is determined by means of empirical data presented in FIG. 4. These data result from extensive trial and error comparison of computer calculations and actual experience.
  • the new temperature of the bath is calculated by summing the various contributions and is stored in memory in addition to the new composition and weight data to'replace the previous conditions at the start of the preparatory next succeeding time interval.
  • the computer has computed the new bath composition and temperature a determination is made as to whether the ratio of oxygen to inert gas should be adjusted. This determination is made for each cycle, i.e., each time the computer irterrogates the progress of the heat. As explained earlier, this should be done at intervals of less than 2 minutes apart to conform to the theoretical assumption of a single reaction predominating during such time interval. It should be understood that the computer interrogates the progress of a heat solely from initial conditions without feedback information from the vessel. Hence, the computer can be operated simultaneously during the actual decarburization of the molten mass or establish beforehand the optimum flow conditions for such decarburization.
  • the computer can conduct the decarburization operation automatically or, alternatively, provide detailed instructions for controlling the operation manually through an operator.
  • the output of the computer 22 is fed into the actuator 30 which in turn regulates the gas flow controls 18 and 20 respectively.
  • the automatic actuator 26 takes the digital output information from the computer and converts such information to appropriate analog electrical signal levels representing the new gas flow rates.
  • the flow controllers 18 and 20 respectively when set for automatic operation, will respond to the new levels thereby adjusting the ratio of gas flow in accordance with the computer command.
  • Actuator 26 is manually preset to establish initial flow conditions. Maintaining accurate fractional ratios, however, between the flow of oxygen and the inert gas requires highly expensive and complex gas flow controller systems.
  • the gas flow controls may be simplified to permit merely whole number ratio adjustments such that, for example, the oxygen to inert gas flow ratios are varied only in a monotonically descending order such as: 4:1, 3:1, 2:1, 1:1, 1:2, etc.
  • manual operation by an operator in response to computer instructions would be preferred.
  • the program would be run through the computer with the computer readout 24 providing detailed instructions as to when to make adjustment to the gas ratio. Instruction would be based upon selecting in sequence the next closest whole integer ratio although the computer can instruct the operator to skip the next closest ratio and go to a subsequent one or, of course, to maintain the same ratio.
  • each succeeding gas ratio is determined in the preferred embodiment illustrated in FIGS. 2 and 2a by comparing the amount of oxidation of a specific element during each time interval with a predetermined critical limit for such element. The selection may also be made based on alternative methods which will be discussed hereafter in connection with the simplified flow chart of H6. 7.
  • the specific element of interest is iron and when using the criterion of limited oxidation for switching, a limit of oxidation is established for each time interval by dividing the total number of time intervals by the maximum acceptable limit of oxidized iron after decarburization.
  • Thelimit for each time interval need not be the same, e.g., a lower limit may be used for a first given number of intervals and the limit then raised for the remaining intervals.
  • the specific element of interest may be any single element selected from the group consisting of chromium, molybdenum and niobium.
  • the limit of oxidation would be established as in the case of low carbon iron.
  • the specific element of interest may be either chromium, molybdenum or manganese.
  • the limit of oxidation would be established as in the case of low carbon iron.
  • percent Cr is the lower limit of chromium content in weight percent at the end of a time interval
  • T is the temperature of the melt in K at the end of a time interval
  • percent C is the percent of carbon in the melt at the end of a time interval
  • percent oxygen is the oxygen volume percent for such time interval.
  • the above formula may also be used to directly calculate the percent 0 that should be employed for the next time interval. This may be done merely by using for percent Cr the calculated chromium content in weight percent at the end of the time interval. This would then determine whether the preceding flow of oxygen should be changed and to what extent.
  • the computer will direct the operator to ignoreany instructions to effect a change in the gas flow control in response to excess oxidation of the element of interest and instead to cause an increase in temperature by heating the molten mass.
  • Such instruction may take the form of command to reset the gas flow control to establish a given flow rate, which may be the same as the existing flow rate or one with a higher proportion of oxygen, in order to prolong or intensify the exothermic reactions occurring in the bath during such time interval thus providing additional heat.
  • the process cycle will then be renewed and the new temperature again evaluated to determine whether it lies within the acceptable band. This will continue until the temperature has risen to or above the acceptable lower limit.
  • An altemative method for increasing the temperature of the molten bath is to add a deoxidizer to the mass such as by the addition of one or a combination of the following: silicon, aluminum, manganese, ferrosilicon, ferrochromium and ferromanganese.
  • a deoxidizer may be used in combination with the first procedure to achieve a quicker response.
  • the computer 22 will direct the operator to cool the heat.
  • the preferred method of cooling the heat is by the addition of scrap.
  • the added scrap material must obviously be compatible with the molten metal composition. in order to avoid piecemeal scrap addition until the bath has cooled to a point in the acceptable band it is preferable that the operator add scrap in accordance with the following formula:
  • T temperature of bath in K T maximum acceptable temperature at the carbon level of the bath in K; T minimum acceptable temperature at the carbon level of the bath in "K and C is a constant.
  • Other fluid coolants may also be used such as steam and carbon dioxide.
  • Another alternative method of cooling which may be used in combination with the above, is to inhibit the flow of oxygen and diluting gas for a predetermined period of time.
  • temperature override as described above is desirable it is not critical in practicing the present invention.
  • the process may be carried out to achieve optimum economics without holding the temperature to within a predetermined temperature band.
  • the program illustrated in the logic diagram of FIGS. 2 and 2a effectively reduces to that shown in FIG. 7 where the block labeled criterion for changing gas flow control would be equivalent to the block labeled element of interest oxidized more than established limit.
  • each succeeding gas ratio may be determined as stated hereinbefore by alternative methods to yield substantially the same result as the preferred method described above.
  • These alternative mehtods are based on information regarding the carbon content, the temperature and the processing time respectively which are regularly monitored and stored by the computer. Temperature override is not necessary for these methods which are schematically described in the flow sheet shown in FIG. 7.
  • Each method is based on a different criterion for changing the gas flow control.
  • discrete gas ratios are predetermined to correspond to carbon content ranges.
  • discrete gas ratios are predetermined to correspond to certain bath temperature ranges.
  • the computer finds that the temperature has progressed from one temperature range into the next, it will render an indication to that effect and signal the operator to switch to the corresponding ratio in the gas flow control sequence.
  • discrete gas ratios are predetermined to correspond to certain time periods relating to periods of progress in the refining operation.
  • the operator is ordered to switch to the next gas ratio in the sequence.
  • the computer issues a final printout indication that the refinement is complete based upon the calculation that the carbon content is below a predetermined level.
  • operation of the process by such alternative methods may not render the optimized economics offered by the preferred embodiment.
  • Appended hereto is a number of illustrative examples of steelmaking computer readout instructions for manual control of the decarburization operation as well as a printout of a complete program for directing the operation of the computer.
  • PROGRAM 23 SHORT TON STAINLESS STEEL AR Argon flow rates in NCFH during various steps (NCF is 70F and 1 atm) (7,600, 8,850, 17,700) OX Oxygen flow rates in NCFH during various periods (22,800, 17,700, 8,850)
  • AP Argon pressure in p.s.i.g.
  • OP Oxygen pressure in p.s.i.g.
  • OT Oxygen inlet temp "F in the plant
  • AT Argop inlet temp F
  • Time of oxygen blow AFEO Activity of FeO CRl percent Start Chromium AMNO Activity of MnO AR(l) Argon correction for temperature and pressure
  • Calculation time (3 secs) PT Print time in min.
  • ASIO, Activity of SiO AQR04 Activity of Cr O SlW Weight of Si in metal in lbs.
  • E Temp rise of system in C TMIN & TMAX define the temperature band SW Weight of slag 8510; SiO in slag SFEO FeO in slag Cl' O in Slag SMNO MnO in slag SCRAP Amount of scrap to cool the bath S Amount of scrap at any instant CS Carbon in scrap in lbs.
  • a process for making steel by refining a predeter a. setting said adjustable control means to establish a first flow rate greater than zero for said oxygen and a first flow rate for said diluting gas;

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  • Engineering & Computer Science (AREA)
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  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
US00194454A 1971-11-01 1971-11-01 Process for the decarburization of molten metal Expired - Lifetime US3816720A (en)

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US00194454A US3816720A (en) 1971-11-01 1971-11-01 Process for the decarburization of molten metal
CA154,770A CA975565A (en) 1971-11-01 1972-10-25 Process for the decarburization of molten metal
AU48332/72A AU478886B2 (en) 1971-11-01 1972-10-31 Process for the decarburization of molten metal
FR7238636A FR2161942B1 (es) 1971-11-01 1972-10-31
AT927772A AT339938B (de) 1971-11-01 1972-10-31 Verfahren zur herstellung von stahl
BR007623/72A BR7207623D0 (pt) 1971-11-01 1972-10-31 Processo para tornar otima a descarburacao de uma massa pre-determinada de metal fundido e o processo a ser executado com auxilio de computador
DE2253480A DE2253480C3 (de) 1971-11-01 1972-10-31 Verfahren zum Entkohlen einer Metallschmelze
ES408142A ES408142A1 (es) 1971-11-01 1972-10-31 Un procedimiento para fabricar acero por afino de una masa predeterminada de metal fundido.
SE7214068A SE413780B (sv) 1971-11-01 1972-10-31 Sett for reglering av stalferskning
JP47108572A JPS5226212B2 (es) 1971-11-01 1972-10-31
IT53748/72A IT966875B (it) 1971-11-01 1972-10-31 Procedimento per la decarburazione di metalli fusi

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JP (1) JPS5226212B2 (es)
AT (1) AT339938B (es)
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CA (1) CA975565A (es)
DE (1) DE2253480C3 (es)
ES (1) ES408142A1 (es)
FR (1) FR2161942B1 (es)
IT (1) IT966875B (es)
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US4113469A (en) * 1976-04-30 1978-09-12 British Steel Corporation Refining molten metal
US4187541A (en) * 1977-06-13 1980-02-05 Institut Kibernetiki Akademii Nauk Ukrainskoi Ssr Digital analyzer for determining liquidus temperature of metals and alloys
US4190888A (en) * 1977-06-13 1980-02-26 Institut Kibernetiki Akademii Nauk Ukrainskoi S S R Digital device for determining carbon content in iron-carbon melts
US4198679A (en) * 1977-06-28 1980-04-15 Institut Kibernetiki Akademii Nauk Ukrainskoi Ssr Method and device for discriminating thermal effect of phase transformation of metals and alloys in the process of their cooling
JPS57145917A (en) * 1981-03-03 1982-09-09 Sumitomo Metal Ind Ltd Refining method for high chromium steel
US4436553A (en) 1982-01-22 1984-03-13 Union Carbide Corporation Process to produce low hydrogen steel
DE3311232A1 (de) * 1983-03-21 1984-10-11 Nippon Yakin Kogyo K.K., Tokio/Tokyo Verfahren zum decarbonisieren von geschmolzenem metall
EP0160375A2 (en) * 1984-04-26 1985-11-06 Allegheny Ludlum Steel Corporation System and method for producing steel in a top-blown vessel
US4647019A (en) * 1986-04-01 1987-03-03 Union Carbide Corporation Very small refining vessel
US4708738A (en) * 1986-04-01 1987-11-24 Union Carbide Corporation Method for refining very small heats of molten metal
US4711430A (en) * 1986-04-01 1987-12-08 Union Carbide Corporation Side-injected metal refining vessel and method
EP0545379A1 (en) * 1991-12-03 1993-06-09 Praxair Technology, Inc. Method of decarburizing molten metal in the refining of steel using neural networks
US5442570A (en) * 1991-09-10 1995-08-15 Nippon Steel Corporation Method of controlling heat input to an alloying furnace for manufacturing hot galvanized and alloyed band steel
US5522915A (en) * 1993-09-03 1996-06-04 Heraeus Electronite Japan, Ltd. Method and apparatus for sequentially and continuously determining concentrations of carbon, hydrogen, and nitrogen in molten steel, and method and apparatus for rapidly determining trace amounts of carbon in molten steel
US6093235A (en) * 1995-10-23 2000-07-25 Mannesmann Ag Process for decarbonising a high-chromium steel melt
WO2002075003A2 (en) * 2001-03-21 2002-09-26 Thyssenkrupp Acciai Speciali Terni S.P.A. Argon oxygen decarburisation converter control method and system
DE4324528C2 (de) * 1993-07-21 2002-12-12 Siemens Ag Recheneinrichtung zur Bestimmung von Entschwefelungszusätzen für eine Stahlschmelze und Stahlschmelze mit Entschwefelungszusätzen
US20040006435A1 (en) * 1999-02-18 2004-01-08 Furnace Control Corp. Systems and methods for controlling the activity of carbon in heat treating atmospheres
US20040182203A1 (en) * 2001-07-02 2004-09-23 Ryuji Nakao Method for decarbonization refining of chromium-containing molten steel
US6854573B2 (en) 2001-10-25 2005-02-15 Lord Corporation Brake with field responsive material
US20070181391A1 (en) * 2001-10-25 2007-08-09 St Clair Kenneth A Brake with field responsive material
CN113523291A (zh) * 2021-07-09 2021-10-22 辽宁冠达新材料科技有限公司 一种气雾化制备a100超高强度合金钢粉末的方法

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JPS5855519A (ja) * 1981-09-29 1983-04-01 Nippon Yakin Kogyo Co Ltd コンピユ−タ−・シミユレ−シヨンによるａｏｄ炉操業の制御方法
US4551175A (en) * 1984-04-17 1985-11-05 Union Carbide Corporation Method for controlling slag chemistry in a refining vessel
DE3601337A1 (de) * 1986-01-16 1987-07-23 Mannesmann Ag Verfahren zur herstellung hochlegierter staehle im sauerstoffblaskonverter
DE102018121232A1 (de) * 2018-08-30 2020-03-05 Sms Group Gmbh Verfahren zur analytischen Bestimmung des kritischen Prozessmoments bei der Entkohlung von Stahl- und Legierungsschmelzen

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US4113469A (en) * 1976-04-30 1978-09-12 British Steel Corporation Refining molten metal
US4187541A (en) * 1977-06-13 1980-02-05 Institut Kibernetiki Akademii Nauk Ukrainskoi Ssr Digital analyzer for determining liquidus temperature of metals and alloys
US4190888A (en) * 1977-06-13 1980-02-26 Institut Kibernetiki Akademii Nauk Ukrainskoi S S R Digital device for determining carbon content in iron-carbon melts
US4198679A (en) * 1977-06-28 1980-04-15 Institut Kibernetiki Akademii Nauk Ukrainskoi Ssr Method and device for discriminating thermal effect of phase transformation of metals and alloys in the process of their cooling
JPS6150122B2 (es) * 1981-03-03 1986-11-01 Sumitomo Metal Ind
JPS57145917A (en) * 1981-03-03 1982-09-09 Sumitomo Metal Ind Ltd Refining method for high chromium steel
US4436553A (en) 1982-01-22 1984-03-13 Union Carbide Corporation Process to produce low hydrogen steel
DE3311232A1 (de) * 1983-03-21 1984-10-11 Nippon Yakin Kogyo K.K., Tokio/Tokyo Verfahren zum decarbonisieren von geschmolzenem metall
US4512802A (en) * 1983-03-21 1985-04-23 Nippon Yakin Kogyo Kabushiki Kaisha Process for the decarburization of molten metal
EP0160375A2 (en) * 1984-04-26 1985-11-06 Allegheny Ludlum Steel Corporation System and method for producing steel in a top-blown vessel
EP0160375A3 (en) * 1984-04-26 1989-07-26 Allegheny Ludlum Steel Corporation System and method for producing steel in a top-blown vessel
US4647019A (en) * 1986-04-01 1987-03-03 Union Carbide Corporation Very small refining vessel
US4708738A (en) * 1986-04-01 1987-11-24 Union Carbide Corporation Method for refining very small heats of molten metal
US4711430A (en) * 1986-04-01 1987-12-08 Union Carbide Corporation Side-injected metal refining vessel and method
US5442570A (en) * 1991-09-10 1995-08-15 Nippon Steel Corporation Method of controlling heat input to an alloying furnace for manufacturing hot galvanized and alloyed band steel
EP0545379A1 (en) * 1991-12-03 1993-06-09 Praxair Technology, Inc. Method of decarburizing molten metal in the refining of steel using neural networks
US5327357A (en) * 1991-12-03 1994-07-05 Praxair Technology, Inc. Method of decarburizing molten metal in the refining of steel using neural networks
DE4324528C2 (de) * 1993-07-21 2002-12-12 Siemens Ag Recheneinrichtung zur Bestimmung von Entschwefelungszusätzen für eine Stahlschmelze und Stahlschmelze mit Entschwefelungszusätzen
US5522915A (en) * 1993-09-03 1996-06-04 Heraeus Electronite Japan, Ltd. Method and apparatus for sequentially and continuously determining concentrations of carbon, hydrogen, and nitrogen in molten steel, and method and apparatus for rapidly determining trace amounts of carbon in molten steel
US6093235A (en) * 1995-10-23 2000-07-25 Mannesmann Ag Process for decarbonising a high-chromium steel melt
US20040006435A1 (en) * 1999-02-18 2004-01-08 Furnace Control Corp. Systems and methods for controlling the activity of carbon in heat treating atmospheres
WO2002075003A2 (en) * 2001-03-21 2002-09-26 Thyssenkrupp Acciai Speciali Terni S.P.A. Argon oxygen decarburisation converter control method and system
WO2002075003A3 (en) * 2001-03-21 2003-02-13 Thyssenkrupp Acciai Speciali Argon oxygen decarburisation converter control method and system
US20040182203A1 (en) * 2001-07-02 2004-09-23 Ryuji Nakao Method for decarbonization refining of chromium-containing molten steel
US6830606B2 (en) * 2001-07-02 2004-12-14 Nippon Steel Corporation Method for decarbonization refining of chromium-containing molten steel
US6854573B2 (en) 2001-10-25 2005-02-15 Lord Corporation Brake with field responsive material
US20050126871A1 (en) * 2001-10-25 2005-06-16 Lord Corporation Brake with field responsive material
US20070181391A1 (en) * 2001-10-25 2007-08-09 St Clair Kenneth A Brake with field responsive material
CN113523291A (zh) * 2021-07-09 2021-10-22 辽宁冠达新材料科技有限公司 一种气雾化制备a100超高强度合金钢粉末的方法
CN113523291B (zh) * 2021-07-09 2023-08-15 辽宁冠达新材料科技有限公司 一种气雾化制备a100超高强度合金钢粉末的方法

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AT339938B (de) 1977-11-10
BR7207623D0 (pt) 1973-08-21
FR2161942B1 (es) 1977-04-01
JPS5226212B2 (es) 1977-07-13
FR2161942A1 (es) 1973-07-13
DE2253480C3 (de) 1978-03-16
DE2253480A1 (de) 1973-05-03
CA975565A (en) 1975-10-07
ATA927772A (de) 1977-03-15
IT966875B (it) 1974-02-20
ES408142A1 (es) 1976-02-01
SE413780B (sv) 1980-06-23
DE2253480B2 (de) 1977-07-28
JPS4852603A (es) 1973-07-24
AU4833272A (en) 1974-05-02

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