CN1026175C

CN1026175C - Method for controlling the homogeneity of ingredients in ingot making

Info

Publication number: CN1026175C
Application number: CN92108421A
Authority: CN
Inventors: 向大林; 朱孝渭; 王克武
Original assignee: SHANGHAI HEAVY-DUTY MACHINERY PLANT
Current assignee: SHANGHAI HEAVY-DUTY MACHINERY PLANT
Priority date: 1992-05-15
Filing date: 1992-05-15
Publication date: 1994-10-12
Anticipated expiration: 2007-05-15
Also published as: CN1078416A

Abstract

The present invention relates to a method for obtaining the uniformity of control ingredients of steel ingot, which aims of solving the problem that a the uniformity of ingredients of an electroslag ingot can not be remelted by self-consuming electrodes of different ingredients of multiple furnaces, and thus, large steel ingots with high uniformity can be economically and effectively obtained by a small furnace. The present invention is a smelting method that determined self-consuming electrodes of the same heat number are respectively used by each phase of an electroslag furnace, or ingredients of a molten pool keeps consistent height from beginning to end in the process of smelting by the rational combination of the electrodes, and simultaneously, the melting loss of active elements can be controlled by deoxidization so as to enable ingredients of an electroslag ingot to reach uniform height. The present invention obtains favorable effects by the implementation and the application of batch production.

Description

Method for controlling the homogeneity of ingredients in ingot making

The present invention relates to the conventional method of electroslag remelting, it is a kind of process for making technology, this technology is intended to solve the discrepant consutrode remelting of many stoves composition is become the homogeneity of ingredients problem of an ESR ingot, thereby obtains the large steel ingot of high uniformity cost-effectively by bogey.

Large-scale ESR ingot is in order to production high-quality heavy forging, because the ESR ingot high purity can make the heavy forging percent defective reduce to minimum, heavy forging is single-piece production normally, one is worth hundreds thousand of units and even millions of unit, and the decline a little of percent defective will reduce production costs greatly.Since ESR ingot utilization rate height, the heavy forging of production constant weight, required steel ingot tonnage is little, and this just makes factory building foundation, workshop scale, lifting transportation and postorder process equipment capacity greatly reduce.Particularly adopt the process that the consutrode remelting of many stoves melting is become an ESR ingot, also can save the number of building large-scale steelmaking equipment and directly utilize original low capacity converter to produce large steel ingot in hundred million yuan huge investment.For the forging that obtains the identical weight of substance more than hundred tons, adopting this equipment investment of producing large steel ingot with little molten big electroslag remelting process only is 10% of traditional method.But more serious inhomogeneities appears in the chemical composition of this steel ingot easily, even unacceptable segmentation phenomenon might appear in the chemical composition on the steel ingot short transverse.This is because the chemical composition of the consutrode of each heat (batch) number melting can not be accomplished in full accordly, even also has bigger difference between each stove of some active element contents.The use although electrode can be arranged in pairs or groups, collocation can not be dealt with problems fully, usually attends to one thing and lose sight of another, such as, put up with C and just do not turned round and look at Si, put up with Si and just do not turned round and look at Mn, also have Cr, Ni, Mo, V etc.In addition, large-scale electroslag remelting complicated condition is changeable, and such as long owing to smelting time, oxidizing atmosphere is strong, and the slag ingredient variation waits reason greatly, and along with the carrying out of remelting, serious scaling loss will take place the active element in the steel.Therefore, must must there be reliable and perfect special technique to solve homogeneity of ingredients control problem by coming the large-scale ESR ingot of production high-quality greatly with little melting.

BP GB1358776 and Japan specially permit out hope and disclose clear 51-12284 and disclose a kind of method of electroslag casting in batches of producing large steel ingot.It is that molten steel is poured in the water cooled mo(u)ld of high-temperature slag under topped to produce large steel ingot in batches.Required molten steel can be repeatedly melting of a stove, also can be the melting of many stoves intersections.Like this, with little molten big the same,, just can produce large-scale steel ingot with the converter of low capacity by to water for a short time greatly.The large-scale steel ingot requirement is few after all, and it is the same with little molten big method to produce large steel ingot by this method, has saved greatly and has built the needed huge investment of large-scale smelting equipment.But it is very strict to furnace charge and smelting technology requirement, and the smelting technology of each stove furnace charge all must be highly consistent each other.Obviously, this is difficult to accomplish.Therefore, can think, the homogeneity of ingredients problem of this method of electroslag casting is not in batches solved yet at all, and will inevitably there be uneven components to a certain degree in the large-scale steel ingot of being cast, because of composition segmentation phenomenon also can appear in the component difference of each batch molten steel on the steel ingot short transverse.In addition, the steel ingot of casting in this way expends time in very long, and risk is bigger.Such as the steel ingot of 200 tons of weights of casting, first pours into about 10 tons of molten steel, treats to have solidified the second batch of molten steel that just can pour into over half.So repeatedly repeatedly, pour into some batches of molten steel, be 4～5 hours every batch blanking time.Also need the long heat-sealing top feeding time at last.Well imagine that the steel ingot that waters into one 200 tons will be for a long time.The high-temperature operation time is once long risky, the timely supply of the grasp of the reliability of metallurgical equipment and casting system, casting bay interval, molten steel and the organizational scheduling of overall processes such as temperature control, melting and casting all must be very strict, otherwise, some links go wrong, and just may cause giving up halfway.In case casting does not become, and will cause heavy economic losses.

The purpose of this invention is to provide a kind of method and solve electroslag remelting with little molten big homogeneity of ingredients problem.

The objective of the invention is to realize: become an ESR ingot in heterogeneous (being made as the n phase, n 〉=2) electroslag furnace, to carry out usually some consutrode remeltings of many heat (batch) numbers of bogey melting by following method.Employed electrode heat (batch) number number is consistent with the number of phases (n) of electroslag furnace; The radical of each stove electrode identical (being made as the m root), m decides according to ESR ingot weight.When bipolar series is every when using two electrodes mutually, the electrode furnace number also can be 2n, and the electrode sum then is the 2mn root.In heavy molten process, each uses the electrode of a heat (batch) number mutually respectively, and bipolar series electroslag furnace uses the electrode of two heat (batch) numbers when also can be every identical.The electrode of any phase is molten to be finished when changing electrode, changes to each electrode of own employed that (or two) heat (batch) number mutually all the time, until all electrodes use up the ESR ingot that reaches predetermined heavy till.When the electrode furnace number was not 1～2 times of the electroslag furnace number of phases, except every heat (batch) number of assert mutually, the electrode of remaining heat (batch) number must intert equably in each phase electrode and uses.In the reflow process, carry out deoxidation with Al, Ca-Si, Ca-Al are at least a, the deoxidier consumption is 0.8～2.0kg/t, makes △ SiO in the slag ₂≤ 0.15Wt-%/h, △ MnO≤0.05Wt-%/h.

The present invention is described in further detail below by some embodiment.

Embodiment 1: tens of electroslag ingots implementing the present invention's production in the three-phase bipolar series electroslag furnace heavily are that the 90-180 ton does not wait.When the ESR ingot of 180 tons of weights of melting, use 6 stove electrodes, 7 in every stove, every two stove electrodes that use mutually, each one in each two stoves.In the reflow process, the electrode of any phase changes to the pair of electrodes of these mutually employed those two heat (batch) numbers when molten finishing, until the 7th pair of electrode.Meanwhile, with Al and Ca-Si deoxidation, its consumption is 0.4-0.8Kg/t.△ SiO in the slag ₂Be 0.12-0.15Wt-%/h, △ MnO is 0.02-0.04Wt-%/h.The component difference of 6 stove electrodes is: △ C=0.09Wt-%, △ Si=0.12Wt-%, △ Mn=0.13Wt-%, △ Cr=0.25Wt-%, △ Mo=0.13Wt-%, △ V=0.05Wt-%.And the component difference in the product is: △ C=0.03Wt-%, △ Si=0.02Wt-%, △ Mn=0.03Wt-%, △ Cr=0.04Wt-%, △ Mo=0.05Wt-%, △ V=0.02Wt-%.

Embodiment 2: in above-mentioned electroslag furnace with 40 stove electrode remeltings 10 ESR ingots, every technology ingot heavily is the 115-120 ton.Every ESR ingot is formed by 4 stove electrode remeltings, and wherein a stove electrode is allocated in A, B, C and intert uses in mutually.Use the Al deoxidation, its consumption is 1.5～2.0kg/t.△ SiO in the slag ₂Be 0.08～0.1Wt-%/h, △ MnO is 0.01-0.03Wt-%/h.The composition fluctuation range of 40 stove electrodes is △ C=0.12Wt-%, △ Si=0.18Wt-%, △ Mn=0.35Wt-%, △ Cr=1.47Wt%, △ Mn=0.34Wt-%; All quite even in order to 10 hundred tonnes of ESR ingots producing: △ C=0.02Wt-%, △ Si, △ Mn=0.04Wt-%, △ Cr, △ Mo=0.05Wt-% along every of the component distributing on the high direction of ingot.

The present invention has following effect:

1, the present invention is in implementation process, the metal bath composition is from start to finish identical, simultaneously by the strict scaling loss of controlling active element of deoxidation operation, process of setting carries out under the pressure cooling that is conducive to eliminate segregation again in addition, therefore, this has just fundamentally solved the homogeneity of ingredients problem, the segmentation phenomenon of uneven components occurs especially till the ass ascends the ladder in the steel ingot short transverse. The present invention not only can make each position composition of steel ingot reach highly even, and it can also make the various compositions between steel ingot and the steel ingot be consistent. This had been the uniformity of each position performance of forging both just, and was to be established by the whole series that some heavy forgings assemble The uniformity of standby each forging performance has been created precondition. Therefore, the present invention makes for great type equipment and especially is significant.

2, the present invention does not have specific (special) requirements to electrode composition, even can use part composition height electrode out of frame.

3, when the electrode furnace number was 1～2 times of the electroslag furnace number of phases, the electrode preparation in the electrode production of steelshop and electroslag workshop can be carried out synchronously, so the present invention can shorten the production cycle greatly, enhanced productivity.

4, the present invention is simple and easy to do, the security reliability height that practices, and this production for large-scale steel ingot especially is significant.

Claims

1, a kind of inhomogeneity method of steel ingot control composition of producing, it is a kind of electric dreg remelting technology that consutrode remelting in heterogeneous electroslag furnace of many stoves melting is become an ESR ingot, the stove number that it is characterized in that employed consutrode is consistent with the number of phases of electroslag furnace, the electrode radical of each stove is identical, and the total amount of electrode is the weight of ESR ingot; In reflow process, each uses the electrode of a heat (batch) number mutually respectively, and the electrode of any phase is molten to be finished when changing electrode, changes to each electrode of own employed that heat (batch) number mutually all the time, uses up until all electrodes, reaches till the ESR ingot weight.

2, a kind of inhomogeneity method of steel ingot control composition of producing, it is a kind of electric dreg remelting technology that consutrode remelting in heterogeneous electroslag furnace of many stoves melting is become an ESR ingot, it is characterized in that when heterogeneous electroslag furnace be under the every situation of using two electrodes mutually of bipolar series, the stove number of consutrode also can be the twice of the electroslag furnace number of phases, the electrode radical of every stove is identical, and the total amount of electrode is the weight of ESR ingot; In reflow process, every electrode that uses two heat (batch) numbers when identical, the electrode of any phase is molten to be finished when changing electrode, changes to each electrode of own employed those two heat (batch) numbers mutually all the time, uses up until all electrodes, reaches till the ESR ingot weight.

3, a kind of inhomogeneity method of steel ingot control composition of producing, it is a kind of electric dreg remelting technology that consutrode remelting in heterogeneous electroslag furnace of many stoves melting is become an ESR ingot, it is characterized in that when the electrode furnace number is not 1～2 times of the electroslag furnace number of phases, except the electrode of every heat (batch) number of use assert mutually, the electrode of remaining heat (batch) number must intert equably in each phase electrode and uses.

4, as claim 1 or the 2 or 3 said inhomogeneity methods of steel ingot control composition of producing, it is characterized in that in reflow process, use the deoxidier deoxidation, keep Si, the rate of rise of Mn isoreactivity element oxide in slag to be: △ SiO ₂≤ 0.15Wt-%/h, △ MnO≤0.05Wt-%/h.