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+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 17:25 |
 

Method_for_increasing_vessel_lining_life.pdf

Abstract
A method for increasing the life of the refractory lining of a basic-refractory-lined vessel for the production of steel by blowing oxygen into a ferrous melt from above the surface of the melt, comprising:


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:41 |
Method_for_providing_steel_with_lowered_.pdf

 

Abstract
A method is provided for obtaining steel with lowered hydrogen levels after ladle treatment. The method includes covering molten steel in the ladle with a particulate mixture consisting essentially of calcium aluminate and dolomitic limestone. The mixture is used in amounts of about 5 to 25 pounds per net ton of molten steel. Using the method of this invention, some steels to be cast without vacuum degassing to reduce the hydrogen level.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:38 |
 

Steel_ladle_desulfurization_compositions.pdf

 

Abstract


A ladle desulfurization composition and method are provided in which molten steel to be desulfurized is mixed with a mixture of particulate metallic aluminum, fluorspar and lime to deoxidize and desulfurize the metal and form a fluxed slag.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:32 |
 

 

Carrier_material_and_desulfurization_age.pdf

Abstract
A particulate carrier material for use with particulate passivated magnesium for injection into molten iron to desulfurize the iron, improve characteristics of the slag and increase iron yield. Material flow of a transport gas and the carrier material is established in a lance prior to inserting the lance into a ladle-contained molten iron, then following insertion the passivated magnesium is added to the material flow. A second embodiment of the invention for iron desulfurization, blends the carrier material and passivated magnesium into a single desulfurization agent. In both embodiments the particulate magnesium is 14-20 mesh with the remaining particulate material being about 200 mesh. The composition of the carrier material is 54-74% calcium oxide, 19-32% aluminum oxide, no more than 4% magnesium oxide, no more than 10% calcium fluoride, no more than 2.5% silicon dioxide, no more than 1.0% iron oxide, no more than 0.025% phosphorus pentoxide, no more than 0.025% titanium...

 


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:28 |
 

Exothermic_steel_ladle_desulfurizer_and_.pdf

Abstract
An exothermic, reducing and basic ladle desulfurizing mix, and method for its use, which minimizes the temperature drop encounterd by the molten steel tapped from the furnace. The mix is comprised essentially of finely-divided particulate iron and/or manganese oxide, aluminum with minor magnesium and/or calcium alloying additions, and burnt lime. The need for other fluxing agents such as fluorspar is minimized or eliminated.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:24 |
Method_of_and_device_for_the_simultaneou.pdf

 

Abstract
Heat and melt-refining reactants are simultaneously delivered to a metal melt by introducing into the melt a filled wire comprising a metal sheath and a mixture of an oxygen supplier and a metal oxygen acceptor capable of undergoing exothermic reaction to produce the melt-refining substances.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:21 |
Abstract

A method and apparatus for incorporating a normally oxidizable and/or volatile additive into a molten metal bath disposed in a vessel with a relatively gas tight cover thereover. A gas which is normally nonreactive with the additive is introduced, in one form of the invention, through a porous refractory plug in the bottom of the vessel and this gas bubbles up through the molten metal agitating the metal and fills the space above the metal and under the cover with at least a small positive pressure of the gas. This gas substantially excludes air from the space above the metal. A gas outlet is provided in the cover and is controllable for the purpose of regulating the outflow of gas to atmosphere thereby regulating the gas pressure above the metal surface. An additive container or hopper directly communicates by way of a valve with the space above the metal so that when desired an additive can be introduced into the molten metal. Cooling means are disclosed to condense any volatilized additive.



ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:17 |
Abstract

A steel melt is confined and subjected to a partial vacuum. A particulate additive is entrained by a neutral nonreactive carrier gas and introduced into the melt below the surface thereof at a depth such that the additive is immediately vaporized and rises toward the surface of the melt in the form of bubbles which react with components of the melt. With particulate calcium as the additive an injection depth 1500 mm, a temperature of approximately 1500.degree.C, and a vacuum of 20 Torr allows the sulfur content of a steel melt readily to be reduced below 0.005% by weight.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:16 |
Abstract

Process of producing chrome steels of a chromium content of about between 16 to 30 percent and low carbon and nitrogen contents. According to the process, a pig iron charge having a high chromium content and a carbon content of from 2 to 7 percent is refined by blowing with very pure oxygen under reduced pressure conditions, the oxygen being introduced into the melt below the level of the melt. The process is applicable to both ferritic and austenitic chrome steel production. The application also discloses a novel bottom-blown converter construction for carrying out the refining procedure.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:15 |
Abstract

A process for making a chromium alloy containing from about 10 percent to about 30 percent chromium and the remainder essentially iron comprises refining a pig iron melt containing chromium in a converter by blowing oxygen jets into the melt under the melt surface in the converter, the oxygen jets each being surrounded by a sheath of a jacket gas such as propane which is slow to react with the melt in order to protect the lining of the converter and the nozzles through which the oxygen jets are blown. The pig iron itself may contain the chromium or the chromium may be added to the melt in the form of a chromium alloy after an initial refinement of the pig iron melt in the converter and in this case further refinement by the introduction of the jacketed oxygen jets into the melt takes place after the chromium has been added. After the oxygen blowing there may be a final blow using jets of argon in place of the oxygen


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:13 |
Abstract

A process for increasing the relative proportion of nickel in a nickel melt which originally contains as little as 20% nickel and the balance principally iron and non-metal contaminants, which comprise blowing a stream of oxygen mixed with a cooling agent into said melt through at least one double pipe tuyere, the oxygen and cooling medium being blown in through the center pipe and a stream of hydrocarbon being blown into the melt through the space between both of said pipes, the refining, cooling and protecting materials all being injected below the surface of said melt.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:11 |
Abstract

The present invention relates to a) a method for refining metal in which, e.g., oxygen and fine lime are introduced through at least one nozzle disposed below a molten bath surface in the refining vessel and a gas is fed in through one or a plurality of further nozzles associated with each first nozzle and to b) an apparatus for practicing the method.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:10 |
Abstract

A hign-carbon ferro-alloy, specifically ferrochrome or ferromanganese, is carburized in a converter in which oxygen or air is blown from below into the melt together with a surrounding protective gas. With the bath preheated to a temperature somewhat higher than the melting point of the ferro-alloy, the oxygen is introduced at such a rate that its reaction with the chromium or the manganese locally superheats the bath, in a region well below the surface and spaced from the converter walls, to a temperature high enough to let the resulting oxides react endothermically with the carbon. This reaction takes place in combustion zones believed to be localized in gas bubbles formed above the injection nozzles, the oxidation of the ferrous and nonferrous constitutents occurring at the interface between the gas and the melt with formation of a very thin and highly reactive oxide skin around each bubble. Some high-melting oxides of chromium or manganese may remain after the oxygen blow but can be reduced by blowing in powdered lime, after and possibly also with the oxygen, and by the deposition of solid or liquid reducing agents on the bath surface. A minor fraction of the ferro-alloy may be added in solid form to hold down the bath temperature.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:8 |
Process_and_apparatus_for_refining_steel.pdf

 

Abstract
A process and apparatus for the desulphurization, deoxidation and purification of a metal melt is presented. The process is particularly well suited for use in a ladle during the refining of steel. The present invention comprises means for defining at the surface of a melt at least a first working zone preferably via a plunger tube. Thereafter, combustible materials and oxygen are delivered to the working zone at a single impact point, preferably by a plurality of lances or by a multiple flow lance. As a result, a reactive high temperature slag is produced thereby. Finally, the melt is mixed so as to evenly distribute the heat preferably by permeable elements and/or at least one auxiliary lance.

 


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:5 |
 

PROCESS_FOR_THE_PRODUCTION_OF_STEELS_HAV.pdf

 

Abstract

An improvement in a process for removing carbon from a chromium-containing molten steel wherein an unidirectional flowing stream is maintained within a bath of molten steel by the injection in such molten steel of a gaseous oxidizing stream, which improvement retains high chromium content in the final refined steel while minimizing carbon content, the improvement being provided by a process which comprises introducing a reducing agent into said unidirectional flowing stream at a point downstream of the point wherein said gaseous oxidizing stream contacts said molten steel.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 16:0 |
Abstract

Porosity and chemical segregation along the center line of a continuously cast steel billet strand are minimized by controlling the cooling and solidification of the continuously cast strand in such fashion that the central region solidifies in a vertical freezing mode. The transverse freezing which proceeds from the skin inward is retarded until such time as the temperature of the molten central region favors vertical solidification, whereafter the billet strand is further cooled to allow completion of its solidification in the vertical mode.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 15:52 |
Fe_Cr_Mn_Alloy.pdf

 

Abstract
An Fe-Cr-Mn alloy is disclosed which has the following composition by wt% and corrosion resistance of which is improved and deterioration in its strength is prevented at grain boundaries due to irradiation of high-energy particles such as neutrons: 5 to 40% of Mn, 5 to 18% of Cr, 2.0 to 12% of Al and the balance of Fe except for unavoidable impurities. In the alloy according to the present invention, Al is added to an Fe-Cr-Mn alloy by a restricted quantity as a main component element. As a result of the addition of Al, an alloy can be obtained in which lowering of concentration of Cr at grain boundaries due to irradiation of high-energy particles such as neutrons can be prevented or concentration of the solutes can be raised.

 


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 15:44 |
 

Process_for_adding_calcium_to_a_bath_of_.pdf

Abstract

A process for adding calcium to a bath of molten ferrous material is disclosed in which a calcium metal-containing wire is fed through a refractory lance into the bath. Recirculatory stirring of the molten ferrous material is accomplished with an inert gas flow through the lance. The calcium-containing wire is fed at such a rate that it substantially bends towards the horizontal direction after it leaves the lance and melting of the calcium in the wire occurs primarily in or directly below a region of downwelling of the molten ferrous material. Suitable wire feeding rates will depend upon the disposition of the lance in the bath and the composition (e.g. clad or unclad) and cross-sectional dimensions of the calcium metal-containing wire.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 15:30 |
Grain_refined_austenitic_manganese_steel.pdf

 

Abstract

An austenitic manganese steel microalloyed with nitrogen, vanadium and titanium used for castings such as mantles, bowls and jaws manufactured as wear components of crushers in the mining and aggregate industries, hammers used in scrap shredders, frogs and switches used in railway crossings and buckets and track shoes used in mining power shovels. These novel compositions exhibit a fine grain size having carbonitride precipitates that result in castings having a wear life 20-70% longer than prior art castings. The austenitic manganese steel includes, in weight percentages, the following: about 11.0% to 24.0% manganese, about 1.0% to 1.4% carbon, up to about 1% silicon, up to about 1.9% chromium, up to about 0.25% nickel, up to about 1.0% molybdenum, up to about 0.2% aluminum, up to about 0.25% copper, phosphorus and sulfur present as impurities in amounts of about 0.07% max and about 0.06% max. respectively, microalloying additions of titanium in the amounts of about 0.020-0.070%,...


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 15:22 |
Method_for_controlling_solidification_se.pdf

 

Abstract
In a method for controlling solidification segregation in casting of carbon steel containing 0.53 wt. % or less of carbon, .alpha.-phase stabilizing elements and .gamma.-phase stabilizing elements of the carbon steel are separated from each other at inter-dendritic portions by adding 2 wt. % or less of at least one element selected from the group consisting of Be, Cr, Nb, Sn, Ti, Mo, and V into the molten steel.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 15:17 |
 

METHOD_FOR_CASTING_STEEL_INGOTS.pdf

 

Abstract

In casting steel ingots, e.g., for rolling purposes, the ingot mould is filled with effervescent steel in a single casting operation, after a time the liquid contents are killed by addition of a deoxidizing agent, and thereafter a gas, preferably air, is blown through the molten steel from a lance introduced into the molten steel from above and into proximity to the bottom of the mould. The lance preferably consists of a non-heat-insulating tube of a normal and usual steel composition, and heat discharge from the upper part of the molten steel is preferably decreased by applying an insulating layer locally onto the inner wall of the ingot mould and/or strewing a heat insulating powder onto the steel.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 15:12 |

Melting_method_for_producing_low_chromiu.pdf

Abstract
This invention describes the melting of Fe-Mn-Al Alloys and includes production methods such as non-continuous casting, continuous casting, hot forging, hot rolling, cold rolling, surface finishing, and heat treating. Products produced using one or more of the above said methods include case ingot, billet, bloom, slab, cast piece, hot-rolled plate, hot-rolled coil, bar, rod, cold-rolled strip and sheet, and hot-forged piece. The said alloys consist principally of by weight 10 to 35 percent Mn, 4 to 12 percent Al, 0 to 12 percent Cr, 0.01 to 1.4 percent C, 0.3-1.5 Mo, 0.1-1% S, a small amount of Cu, Nb, V, CO, Ti, B, N, Zr, Hf, Ta, Sc, W, and Ni, and the balanced Fe.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 15:7 |
METHOD_FOR_CONTINUOUSLY_CASTING_STEEL.pdf

 

METHOD FOR CONTINUOUSLY CASTING STEEL BILLET STRANDS TO MINIMIZE THE POROSITY AND CHEMICAL SEGREGATION ALONG THE CENTER LINE OF THE STRAND

Abstract

Porosity and chemical segregation along the center line of a continuously cast steel billet strand are minimized by controlling the cooling and solidification of the continuously cast strand in such fashion that the central region solidifies in a vertical freezing mode. The transverse freezing which proceeds from the skin inward is retarded until such time as the temperature of the molten central region favors vertical solidification, whereafter the billet strand is further cooled to allow completion of its solidification in the vertical mode.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 15:1 |
PROCESS_FOR_TREATMENT_OF_MOLTEN_STAINLES.pdf

 

 

+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 14:55 |
STEEL_INGOT_MAKING_METHOD.pdf

 

Abstract

A method for semi-continuously casting long-length, large steel ingot by ring molten steel into a thin walled, water cooled, long-length mold made of iron, steel or cast iron which does not thermally deform, in contact with the molten steel during pouring and withdrawing the solidifying ingot down through the mold at suitable speed without directly water cooling the solidifying ingot until a predetermined length of ingot is obtained, and then holding the ingot in the mold for a while till the ingot solidify enough to draw out from the mold on to a truck which carry away the said ingot to further processing and apparatus thereof.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 14:47 |
Non_ridging_ferritic_chromium_alloyed_st.pdf

Abstract
A ferritic non-ridging stainless steel and process therefor. A chromium alloyed steel melt is deoxidized with a sub-equilibrium amount of titanium and nitrogen and continuously cast into a strip or a slab or cast into an ingot having an as-cast fine equiaxed microstructure substantially free of columnar grains. The as-cast steel contains .ltoreq.0.010% Al, up to 0.08% C, 0.10-1.50% Mn, .ltoreq.0.05% N, .ltoreq.1.5% Si, 8-25% Cr, <2.0% Ni and is deoxidized with titanium, all percentages by weight, the balance Fe and residual elements. Preferably, the titanium is controlled so that (Ti/48)/�(C/12)+(N/14)!>1.5. A hot processed continuous sheet may be formed from a continuously cast slab without surface grinding, may be descaled, cold reduced to a final thickness and recrystallization annealed. An anneal prior to cold reduction is not required to obtain an annealed sheet essentially free of ridging.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 14:38 |
METHOD_OF_PRODUCING_CHROMIUM_STEEL.pdf

 

+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 14:26 |


Abstract
An improved method for producing alloy steel, comprising the steps of: charging a furnace with materials comprised of iron, carbon and sulfur, and at least one metal from the group consisting of cromium and nickel; melting the charge; desulfurizing the melt to a sulfur level below 0.04 percent, generally below 0.03 percent; decarburizing the desulfurized melt to a carbon level below 0.15 percent, generally below 0.07 percent; deoxidizing the melt; and casting the melt. In addition the method often includes the additional step of finally adjusting the alloy composition for certain elements, such as chromium, prior to decarburizing


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 14:17 |
Process_for_producing_high_chromium_stee.pdf

 

 

Abstract
A process for producing high chromium steel is disclosed which comprises supplying molten iron in a smelting furnace with a solid chromium source, carbonaceous powder and oxygen-containing gas in amounts so controlled as to keep the melt at a temperature in the range of less than 1650.degree. C. and above the minimum melt temperature at the specific carbon and chromium levels in the melt and which is capable of performing preferential decarbonization while inhibiting the oxidation of chromium.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 12:47 |
Martensitic_stainless_cast_steel_having_.pdf

 

Abstract
Martensitic stainless cast steel suitable for use as turbine elements for water power plants having high cavitation erosion resistance and consisting essentially of carbon of 0.1 wt % or less, silicon of 1.0 wt % or less, manganese of 2.0-9.0 (exclusive of 2.0) wt %, nickel of 0.5-8.0 wt %, chromium of 11.0-14.0 wt %, and the balance of essentially iron.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 12:31 |
HIGH_STRENGTH_AND_HIGH__TOUGHNESS_CAST_S.pdf

 

HIGH-STRENGTH AND HIGH-TOUGHNESS CAST STEEL FOR PROPELLERS AND METHOD FOR MAKING PROPELLERS OF SAID CAST STEEL

Abstract

A method of making a high strength, high toughness cast steel marine propeller comprised of not more than 0.25 percent of carbon, not more than 1 percent of silicon, not more than 3 percent of manganese, from 5-20 percent of chromium, from 1-8 percent of cobalt, and from 0.5-7 percent of one or both of molybdenum and tungsten, and the remainder consisting of iron. In addition, the cast steel may contain up to 8 percent of nickel and up to 4 percent of copper, depending on the conditions. The method comprises casting the propeller into individual sections, welding said sections together, heating to a temperature of 800.degree. to 1,000.degree. C. and air cooling. The propeller can be aged by heating to a temperature between 450.degree. and 700.degree. C. If desired, the individual cast sections can be annealed prior to welding.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 12:18 |

 

High_chromium_heat_resistant_cast_steel_.pdf

Abstract
A heat resistant material and a pressure vessel by use thereof, having an excellent high temperature strength so as to be applicable to steam condition of 600.degree. C. or more, are provided. Said material consists of C, Si, Cr, Ni, V, Nb, N, Mo and W in the respective weight percent, and inevitable impurities and Fe, and is further added with Cu, B and Ca and/or Mn, Mn and Cu, B and Ca, in the respective weight percent. Also, a pressure vessel is formed of said materials.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 12:2 |
Abstract

There is provided a method of producing stainless, chromium-steel sheet or strip having a high resistance to corrosion and an improved hardness, and which has a relatively high yield point / ultimate strength ratio in an unhardened state, the starting material used in the method being one of substantially a pearlite structure and in which the material is heated and worked at specific temperatures so as to break down the pearlite structure and transform said structure to one comprising finely-divided spheroidized carbides in a ferritic matrix.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 9:2 |
HOT_HARD_STAINLESS_STEEL.pdf

 

Abstract

A hot hard chromium stainless steel having good hot workability containing about 0.9-1.4% carbon, 13-19% chromium, 1.5-2.75% molybdenum, 0.3-2.5% vanadium, 0.10-0.55% columbium and the balance primarily iron.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 8:52 |
METHOD_OF_HEAT_PROCESSING_ALLOY_STEEL_TO.pdf

+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 8:47 |
Heat_treatment_for_high_chromium_high_ca.pdf

Abstract
A process for softening high carbon, high chromium steel to render it machinable includes pre-heating, homogenizing, isothermally annealing and slow cooling the steel.


ادامه مطلب
+ نوشته شده توسط علی تاجی در یکشنبه 1387/03/26 و ساعت 8:43 |
Method for producing high chromium steels having extremely low carbon and ...

 

Abstract
High chromium steels having extremely low carbon and nitrogen contents are produced by blowing more than 15 up to 40 Nl/min per ton of molten steel of an inert gas into a high chromium steel containing 0.8 to 2.5% of C and 10 to 35% of Cr in a ladle under a reduced pressure from bottom of a ladle and concurrently blowing oxygen gas to the molten steel surface to form 1 to 100 kg per ton of the molten steel of a slag containing not less than 20% of SiO.sub.2 and not more than 25% of Cr.sub.2 O.sub.3 at the end of oxygen blowing, terminating the oxygen blowing when the carbon concentration in the molten steel becomes not more than 0.020%, and subsequently blowing 6 to 40 Nl/min per ton of molten steel of an inert gas under a high vacuum of not more than 10 torr.


ادامه مطلب
+ نوشته شده توسط علی تاجی در شنبه 1387/03/25 و ساعت 18:25 |
_DECARBURIZATION_PROCESS_FOR_HIGH__CHROM.pdf

 

 

+ نوشته شده توسط علی تاجی در شنبه 1387/03/25 و ساعت 18:22 |
Oxygen_injector_means_for_secondary_refo.pdf

 

Abstract
An oxygen injector assembly for directing substantially pure oxygen into the path of an effluent or exhaust stream from a primary reformer process for mixing of the oxygen with the effluent, the assembly comprising an oxygen delivery tube for discharging the oxygen into the path of the effluent, and a cooling jacket disposed around the outer periphery of the delivery tube for moderation of the ambient temperature conditions surrounding the oxygen injector assembly and thus compensating for the increased temperature conditions created by the mixing of the oxygen with the effluent in lieu of mixing air therewith.


ادامه مطلب
+ نوشته شده توسط علی تاجی در شنبه 1387/03/25 و ساعت 18:12 |
Liquid_cooled_lance_for_blowing_oxygen_o.pdf

 

Abstract
A liquid cooled lance is used to blow a primary supply of oxygen at the surface of a molten steel bath to form a burning spot. a central duct in the lance delivers the primary supply of oxygen to the tip. A secondary supply of oxygen is blown from nozzles around the side of the lance to burn up CO from the burning spot and so heat the bath. Several conduits run in parallel within the lance to deliver the secondary oxygen to the nozzles. There is preferably one conduit per nozzle. The conduits may run within an annular coolant duct, and preferably comprise, at least in part, pipes in the form of a winding around the lance axis. This construction has good resistance to thermal expansion stresses.


ادامه مطلب
+ نوشته شده توسط علی تاجی در شنبه 1387/03/25 و ساعت 18:9 |
Simple_ladle_refining_method.pdf

Abstract
The present invention provides a simplified ladle refining process capable of efficiently heating a molten steel in a short period of time while scattering and adhesion of splashes and erosion of refractories are suppressed. A simplified ladle refining process for refining a molten steel in a ladle comprising inserting an immersion snorkel into a ladle and blowing an oxidizing gas onto the surface of a molten steel within the immersion snorkel through a lance while the molten steel is being stirred by blowing an inert gas through the bottom of the ladle, wherein the lance has a ratio (d.sub.0 /d.sub.t) of a nozzle outlet diameter d.sub.0 (mm) to a nozzle throat diameter d.sub.t (mm) of from 1.2.alpha. to 2.5.alpha. wherein .alpha. is defined as a function of a back pressure.

+ نوشته شده توسط علی تاجی در شنبه 1387/03/25 و ساعت 17:59 |
Method_for_direct_use_of_chromite_ore_in.pdf

 

Abstract
A three-stage process for obtaining metallic Cr units insitu during the production of stainless steel. Raw chromite ore or a concentrate produced from chromite ore is mixed with a carbonaceous reductant and slagging agents are added to an iron bath (24) for smelting and refining in a refining reactor (10). During the first stage, partially metallized chromite is smelted by carbon in the reactor that is top-and bottom-blown with oxygen and oxygen-containing gases respectively to produce a chromium alloy bath having a carbon content well below saturation. In the second stage, the alloy bath is decarburized by being bottom stirred with the oxygen-containing gas to the final bath carbon specification. In the third stage, the alloy bath is reduced by a metalloid reductant such as silicon or aluminum and again bottom stirred but with a non-oxidizing gas to achieve a high chromium yield. The reactor includes a top lance (18) extending through...


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        Method_for_refining_chromium_containing_.pdf
+ نوشته شده توسط علی تاجی در شنبه 1387/03/25 و ساعت 17:42 |

Stainless Steel

 

Background

 

Stainless steel is an iron-containing alloy—a substance made up of two or more chemical elements—used in a wide range of applications. It has excellent resistance to stain or rust due to its chromium content, usually from 12 to 20 percent of the alloy. There are more than 57 stainless steels recognized as standard alloys, in addition to many proprietary alloys produced by different stainless steel producers. These many types of steels are used in an almost endless number of applications and industries: bulk materials handling equipment, building exteriors and roofing, automobile components (exhaust, trim/decorative, engine, chassis, fasteners, tubing for fuel lines), chemical processing plants (scrubbers and heat exchangers), pulp and paper manufacturing, petroleum refining, water supply piping, consumer products, marine and shipbuilding, pollution control, sporting goods (snow skis), and transportation (rail cars), to name just a few.

 

About 200,000 tons of nickel-containing stainless steel is used each year by the food processing industry in North America. It is used in a variety of food handling, storing, cooking, and serving equipment—from the beginning of the food collection process through to the end. Beverages such as milk, wine, beer, soft drinks and fruit juice are processed in stainless steel equipment. Stainless steel is also used in commercial cookers, pasteurizers, transfer bins, and other specialized equipment. Advantages include easy cleaning, good corrosion resistance, durability, economy, food flavor protection, and sanitary design. According to the U.S. Department of Commerce, 1992 shipments of all stainless steel totaled 1,514,222 tons.

 


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+ نوشته شده توسط علی تاجی در شنبه 1387/03/25 و ساعت 14:14 |
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+ نوشته شده توسط علی تاجی در دوشنبه 1387/03/20 و ساعت 18:0 |

دانلود کامل       download pdf file 870 KB

September 2000

  

TABLE OF CONTENTS

LIST OF FIGURES ...................................................................................................................... vii

LIST OF TABLES......................................................................................................................... xi

1. INTRODUCTION ................................................................................................................. 1-1

1.1 Purpose................................................................................................................. 1-1

1.2 Background..........................................................................................................1-2

1.3 Scope.................................................................................................................... 1-9

1.4 Special Acknowledgement...................................................................................1-9

2. OVERVIEW OF STEEL MAKING AND PROCESSING................................................... 2-1

2.1 Steel Making ........................................................................................................2-1

2.1.1 Blast Furnace ........................................................................................... 2-1

2.1.2 Open Hearth Furnace (OHF) Steel Making............................................. 2-2

2.1.3 Basic Oxygen Furnace (BOF) Steel Making ........................................... 2-2

2.1.4 Electric Furnace Steel Making................................................................. 2-2

2.1.5 Ladle Metallurgy...................................................................................... 2-4

2.2 Steel Casting and Characteristics......................................................................... 2-5

2.2.1 Ingot Casting............................................................................................ 2-6

2.2.2 Continuous Casting.................................................................................. 2-6

2.3 Characteristics...................................................................................................... 2-7

2.3.1 Microstructure.......................................................................................... 2-7

2.3.2 Steel Composition.................................................................................... 2-8

2.3.2.1 Killed and Semi-Killed Steels................................................... 2-8

2.3.2.2 Segregation ............................................................................. 2-10

2.3.2.2.1 Segregation and Other Defects in Ingot-Based

Products ................................................................ 2-10

2.3.3 Influence of Thermal History................................................................. 2-11

2.3.3.1 Phase Transformations............................................................ 2-11

2.3.3.2 Grain Growth .......................................................................... 2-13

2.3.4 Hot Rolling ............................................................................................ 2-13

2.4 Surface and Embedded Imperfections ............................................................... 2-15

3. MECHANICAL PROPERTIES OF STEELS ....................................................................... 3-1

3.1 Strength................................................................................................................ 3-1

3.1.1 Stress-Strain Curves................................................................................. 3-1

3.1.2 Yield Strength and Tensile Strength........................................................ 3-2

3.1.3 Effects of Stress (Strain) State and Constraint on Strength ..................... 3-4

3.1.4 Effects of Temperature on Strength......................................................... 3-6

3.1.5 Effects of Loading Rates on Strength ...................................................... 3-7

3.2 Ductility ............................................................................................................... 3-9

3.2.1 Effects of Stress (Strain) State and Constraint on Ductility .................... 3-9

3.2.2 Effects of Temperature on Ductility ...................................................... 3-11

3.2.3 Effects of Loading Rate on Ductility..................................................... 3-12

3.3 Fracture Toughness............................................................................................3-12

FEMA-355A

Table of Contents Base Metals and Fracture

iv

3.3.1 Charpy V-Notch Fracture Toughness .................................................... 3-13

3.3.2 Fracture Mechanics Concepts................................................................ 3-13

3.3.2.1 Effect of Stress (Strain) State and Constraint on Fracture

Toughness ............................................................................... 3-14

3.3.2.2 Effect of Temperature on Linear-Elastic Fracture

Toughness ............................................................................... 3-15

3.3.2.3 Effect of Loading Rate on Linear-Elastic Fracture

Toughness ............................................................................... 3-16

3.4 Effects of Plastic Deformation on Steel Properties ........................................... 3-17

4. TENSILE PROPERTIES OF STRUCTURAL STEELS ...................................................... 4-1

4.1 General................................................................................................................. 4-1

4.2 Mill Practice......................................................................................................... 4-1

4.3 Tensile Properties of Currently Produced Rolled Shapes.................................... 4-1

4.3.1 Effect of Coupon Location upon Yield Strength ..................................... 4-3

4.3.2 Effect of Strain Rate upon Yield Strength ............................................... 4-5

4.3.3 Yield to Tensile Strength Ratio ............................................................... 4-5

4.3.4 Inelastic Stress-Strain Behavior of Steels................................................ 4-6

4.4 Strength of Historic Steels ................................................................................... 4-7

4.5 Influence of Dual Graded Steels upon Expected Strength .................................. 4-9

4.5.1 Recommended Changes to ASTM Specification .................................. 4-12

4.6 Summary ............................................................................................................4-12

5. THROUGH-THICKNESS STRENGTH OF ROLLED SECTION FLANGES ................... 5-1

5.1 Introduction..........................................................................................................5-1

5.2 Causes of Anisotropic Behavior of Steel............................................................. 5-1

5.3 Typical Through-Thickness Properties................................................................ 5-2

5.4 Evaluation of Welded T-Joint Connections......................................................... 5-5

5.5 Conclusions..........................................................................................................5-8

6. CHARPY V-NOTICH TOUGHNESS OF ROLLED SHAPES AND PLATE..................... 6-1

6.1 Introduction..........................................................................................................6-1

6.2 Toughness Surveys ..............................................................................................6-1

6.2.1 Plate ......................................................................................................... 6-1

6.2.2 Wide Flange Shape .................................................................................. 6-3

6.3 Summary and Comparison of CVN Toughness Surveys..................................... 6-9

7. MATERIAL PROPERTIES AT k-AREA REGION OF WIDE FLANGE SHAPES........... 7-1

7.1 Introduction..........................................................................................................7-1

7.2 k-Area Properties of Rolled Shapes..................................................................... 7-1

7.3 Conclusions..........................................................................................................7-5

8. STRENGTH VARIATION IN A913 STEEL ....................................................................... 8-1

8.1 Hardness Survey of Shapes.................................................................................. 8-1

8.2 Notch Toughness .................................................................................................8-2

8.3 Strength Variations ..............................................................................................8-2

FEMA-355A

Base Metals and Fracture Table of Contents

v

8.4 Conclusions..........................................................................................................8-3

REFERENCES, FEMA REPORTS, SAC REPORTS, AND ACRONYMS ..............................R-1

SAC PHASE II PROJECT PARTICIPANTS ............................................................................. S-1

 

FEMA-355A

Base Metals and Fracture List of Figures

vii

LIST OF FIGURES<<


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