CN112080682A - Method for increasing vanadium content of molten deformed steel bar by using vanadium-containing titanium-containing pig iron block - Google Patents
Method for increasing vanadium content of molten deformed steel bar by using vanadium-containing titanium-containing pig iron block Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
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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
- C21C7/0068—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 by introducing material into a current of streaming metal
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
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Abstract
The invention discloses a method for increasing the vanadium content of molten deformed steel by using a vanadium-containing titanium-containing pig iron block, which comprises the following steps: selecting molten iron, pretreating the molten iron, casting molten iron, adding a pig iron block, bottom blowing a steel ladle, pouring the treated pig iron block into an alloy chute, adding an alloy and the pig iron block by using the alloy chute in the tapping process of a converter when producing deformed steel bars HRB400E series and HRB500E series, bottom blowing argon or nitrogen for 4 minutes at the flow rate of 40-100 m/h under the pressure of 0.2-0.4 MPa after adding the pig iron block, taking a molten steel sample for component analysis, and finely adjusting the alloy according to the components; and then adjusting the bottom blowing flow to 20-40 m/h for soft blowing for 4-6 minutes, performing the heat of pig iron block adding operation, and improving the tapping temperature of the converter by 5-20 ℃ on the basis of technological parameter requirements. The vanadium-containing titanium-containing deformed steel bar realizes the stable strengthening effect of titanium in the deformed steel bars HRB400E series and HRB500E series, replaces the strengthening effect of partial vanadium, and greatly reduces the production cost of the deformed steel bar.
Description
Technical Field
The invention relates to the field of deformed steel bar production, in particular to a method for increasing the vanadium content of molten steel of deformed steel bar by using vanadium-containing titanium-containing pig iron blocks.
Background
The proportion of the steel for construction is 50 percent for consumption of Chinese steel. As China is in the historical stage of rapid development of urbanization, the demand for building steel is great. As a main building steel material, deformed steel bars occupy a large proportion of the production of Chinese steel materials all the time. The deformed steel bar is commonly known as hot-rolled ribbed steel bar, is necessary steel for more than medium-sized building components, mainly comprises three categories of two, three and four grades, is a single steel type series with the largest capacity and the largest consumption in China, and has the production and sales volume exceeding 2 hundred million tons in 2017 years. In the early 2018, a new screw-thread steel standard GB/T1499.2-2018 is issued to replace GB/T1499.2-2007, and the method is forcibly carried out in 11 and 1 days 2018. 335 MPa-grade steel bars are eliminated in the new standard, and 600 MPa-grade steel bars are added; the number with E is added; properly tightening the quality deviation, and determining that the quality deviation is not allowed to be tested again; the provision of a steel bar fatigue test method is added, and the provision of metallographic structure inspection is added; the cross section Vickers hardness, macroscopic metallographic phase, microscopic structure and inspection method are increased; the allowable deviation of the delivery length is modified; the measuring method of the end clearance of the transverse rib is added. The most obvious characteristics in the new national standard are the tendency of adapting to social development and quality demand promotion, the upgrade and the update of the deformed steel bar are pushed, and the most direct influence on the industry is the regulation of increasing the metallographic structure and the Vickers hardness test: the structure is mainly ferrite plus pearlite, a tempered martensite structure cannot appear in a base circle, and the hardness difference value of two points tested by Vickers hardness is less than or equal to 40 Hv. The method is a fundamental strike to the existing strong water penetration and rolling and cooling control processes of most deformed steel bar enterprises, on one hand, a technical system needs to be reconstructed, and on the other hand, the alloying cost is greatly increased, particularly the cost of the traditional vanadium alloy deformed steel bar production mode. The market reacts to the new national standard quickly and often, and the most direct expression is that the price of the vanadium series alloy (50 base price) rises to 50 ten thousand per ton in a short period from 20 ten thousand per ton in the early 2018, so that great cost pressure is brought to the screw-thread steel enterprises to implement the new national standard. Because titanium resources are abundant in China, production processes are mature, market prices are kept stable for a long time, vanadium resources are extremely short, a large amount of vanadium-containing raw ores are imported for a long time to smelt and produce vanadium-series alloys or directly import vanadium-series alloys, the prices are always high, and along with the implementation of the new national standard of deformed steel bars, most enterprises need to add vanadium-series alloys to realize reinforcement, and the vanadium-series alloys rise by more than 2 times, so that the cost control of deformed steel bar production enterprises is greatly influenced.
At present, the grades of common hot-rolled thread steel produced by the traditional domestic process are divided into three grades of HRB335, HRB400 and HRB 500; in order to improve the earthquake resistance of buildings, earthquake-resistant reinforcing steel bars HRB400E and HRB500E are mainly used at home at present, and in order to achieve the corresponding yield performance of more than 400 MPa and 500 MPa, microalloy strengthening elements such as V, Nb, Ti and the like are mainly added in the alloying process of molten steel, so that the steel has the characteristics of high strength, good toughness, wear resistance, corrosion resistance and the like. However, the main problem of the process is that the vanadium-nitrogen, vanadium-iron and other alloys are expensive, so that the production cost is greatly increased, the profit margin of enterprises is occupied, and the development of the enterprises is not facilitated. Therefore, the research and development of a new alloy product to partially replace V-series alloy and reduce the production cost of deformed steel bar become a problem to be solved urgently in the industry.
Disclosure of Invention
The invention solves the problems that less than or equal to 4 tons of vanadium-containing titanium-containing pig iron blocks are added in the converter tapping process when the deformed steel HRB400E series and the HRB500E series are produced in the prior art, the content of molten steel V, Ti is improved, the consumption of noble alloys such as vanadium nitrogen, ferrovanadium and the like is reduced, and the alloy cost is reduced, and provides a method for increasing the vanadium content of the deformed steel molten steel by using the vanadium-containing titanium-containing pig iron blocks.
The invention is realized by the following technical scheme:
a method for increasing the vanadium content of molten deformed steel by using a vanadium-containing titanium-containing pig iron block comprises the following steps:
s1, selecting molten iron, wherein the molten iron comprises the following components: 3.5 to 4.5 percent of C, 0.01 to 1.0 percent of Si, less than 0.30 percent of Mn, less than or equal to 0.070 percent of P, less than or equal to 0.050 percent of S, more than or equal to 0.20 percent of V, and more than or equal to 0.01 percent of Ti;
s2, preprocessing molten iron, namely performing molten iron slagging-off operation before the molten iron meeting the conditions is used, and removing residues on the inner surface of the molten iron tank, wherein the liquid level of the molten iron is exposed to be more than 90%;
s3, casting blocks by molten iron, and then casting the blocks by using a block casting machine, wherein the block degree is less than or equal to 20 Kg;
s4, hoisting and transferring, wherein the pig iron blocks are bagged and packaged by 0.5-2 tons and are transported into a rectangular hopper at the tapping position of the converter by a hoisting tool (a crown block or a forklift crane), and the preparation amount of the pig iron blocks is less than or equal to 4 tons;
s5, adding a pig iron block, wherein one end of a hopper is connected with an electric hoist lifting hook, the electric hoist is used for lifting, the pig iron block is poured into an alloy chute, when the deformed steel bar HRB400E series and HRB500E series are produced, in the converter tapping process, the alloy and the pig iron block are added by the alloy chute, the adding amount of the pig iron block in each furnace is less than or equal to 4 tons, the using amounts of vanadium nitrogen and vanadium iron are reduced according to the conversion of the V content of the pig iron block, and meanwhile, the using amounts of C powder and silicon-manganese alloy are reduced according to the conversion of the C content, the Si content and the Mn content of the pig iron block;
s6, bottom blowing the steel ladle, after adding the pig iron blocks, bottom blowing argon or nitrogen with the pressure of 0.2-0.4 MPa and the flow rate of 40-100 m/h for 4 minutes, taking a molten steel sample for component analysis, and carrying out alloy fine adjustment according to the components; and then adjusting the bottom blowing flow to 20-40 m/h for soft blowing for 4-6 minutes, performing the heat of pig iron block adding operation, and improving the tapping temperature of the converter by 5-20 ℃ on the basis of technological parameter requirements.
In summary, the following beneficial effects of the invention are:
1. the invention relates to a method for increasing the vanadium content of molten steel of deformed steel by using vanadium-containing titanium-containing pig iron blocks, which realizes the stable strengthening effect of titanium in the deformed steel HRB400E series and HRB500E series, replaces the strengthening effect of partial vanadium, and greatly reduces the production cost of the deformed steel, wherein 1 ton of titanium is added into each furnace in the tapping process of the pig iron blocks, the V content of the pig iron blocks is 0.40 percent, the V can be increased by 0.0028 percent in each ton of molten steel, the vanadium-nitrogen alloy is saved by 0.036 percent per ton of steel, the cost is saved by 0.036 percent by 169.5 percent per Kg by 6.09 percent per ton, and meanwhile, the vanadium-containing titanium-containing deformed steel has the prospect of popularization and application in the production of other vanadium-containing steel.
2. The invention relates to a method for increasing the vanadium content of molten steel of deformed steel by utilizing a vanadium-containing titanium-containing pig iron block, which ensures that the stirring, degassing, impurity removal and other effects of molten steel by argon blowing can be fully reflected and the castability of the molten steel is improved by controlling the operating parameters of bottom blowing argon or nitrogen in stages.
3. According to the method for increasing the vanadium content of the molten steel of the deformed steel bar by using the vanadium-containing titanium-containing pig iron block, the strength of HRB400E series and HRB500E series of the deformed steel bar is effectively improved by controlling the content of elements such as C, V in the steel bar, the mechanical property fluctuation of the finished steel bar is small, and the performances of the HRB400E series and HRB500E series of the deformed steel bar are stable.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 is a schematic view of the process of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
Examples
As shown in figure 1, the method for increasing the vanadium content of the molten deformed steel by using the vanadium-containing titanium-containing pig iron block comprises the following steps: selecting molten iron: the molten iron comprises the following components: 3.5 to 4.5 percent of C, 0.01 to 1.0 percent of Si, less than 0.30 percent of Mn, less than or equal to 0.070 percent of P, less than or equal to 0.050 percent of S, more than or equal to 0.20 percent of V, and more than or equal to 0.01 percent of Ti; carrying out molten iron slagging-off operation before the molten iron meeting the conditions is used, removing residues on the inner surface of the molten iron tank, and exposing the liquid level of the molten iron to more than 90%; then, utilizing an ingot casting machine to cast the ingot, wherein the mass degree is as follows: less than or equal to 20 Kg. The pig iron blocks are bagged and packaged by 0.5-2 tons and are lifted into a rectangular hopper at the tapping position of the converter by a crown block or a forklift, and the preparation amount of the pig iron blocks is less than or equal to 4 tons; one end of the hopper is connected with an electric hoist lifting hook, the electric hoist is used for lifting, and the pig iron blocks are poured into the alloy chute; when producing deformed steel HRB400E series and HRB500E series, adding alloy and pig iron blocks by using an alloy chute in the converter tapping process; the adding amount of the pig iron blocks in each furnace is less than or equal to 4 tons, the using amounts of vanadium nitrogen and ferrovanadium are reduced according to the conversion of the content of V of the pig iron blocks, and the using amounts of C powder and silicon-manganese alloy are reduced according to the conversion of the contents of C, Si and Mn of the pig iron blocks; after adding the pig iron blocks, bottom blowing argon or nitrogen with the pressure of 0.2-0.4 MPa and the flow of 40-100 m/h for 4 minutes; taking a molten steel sample for component analysis, and carrying out alloy fine adjustment according to components; then the bottom blowing flow is adjusted to be 20-40 m/h for soft blowing for 4-6 minutes; and (4) carrying out the heat of the operation of adding the pig iron blocks, wherein the tapping temperature of the converter is increased by 5-20 ℃ on the basis of the technological parameter requirement.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (1)
1. A method for increasing the vanadium content of molten deformed steel by using a vanadium-containing titanium-containing pig iron block is characterized by comprising the following steps:
s1, selecting molten iron, wherein the molten iron comprises the following components: 3.5 to 4.5 percent of C, 0.01 to 1.0 percent of Si, less than 0.30 percent of Mn, less than or equal to 0.070 percent of P, less than or equal to 0.050 percent of S, more than or equal to 0.20 percent of V, and more than or equal to 0.01 percent of Ti;
s2, preprocessing molten iron, namely performing molten iron slagging-off operation before the molten iron meeting the conditions is used, and removing residues on the inner surface of the molten iron tank, wherein the liquid level of the molten iron is exposed to be more than 90%;
s3, casting blocks by molten iron, and then casting the blocks by using a block casting machine, wherein the block degree is less than or equal to 20 Kg;
s4, hoisting and transferring, wherein the pig iron blocks are bagged and packaged by 0.5-2 tons and are transported to a hopper at the tapping position of the converter by a hoisting tool, and the preparation amount of the pig iron blocks is less than or equal to 4 tons;
s5, adding pig iron blocks, wherein one end of a hopper is connected with an electric hoist lifting hook, the electric hoist is used for lifting, the pig iron blocks are poured into an alloy chute, when the deformed steel bar is produced, in the converter tapping process, the alloy and the pig iron blocks are added by the alloy chute, and the adding amount of the pig iron blocks in each furnace is less than or equal to 4 tons;
s6, bottom blowing the steel ladle, after adding the pig iron blocks, bottom blowing argon or nitrogen with the pressure of 0.2-0.4 MPa and the flow rate of 40-100 m/h for 4 minutes, taking a molten steel sample for component analysis, and carrying out alloy fine adjustment according to the components; then the bottom blowing flow is adjusted to be 20-40 m/h for soft blowing for 4-6 minutes.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113637822A (en) * | 2021-07-28 | 2021-11-12 | 河北荣信钢铁有限公司 | Molten steel alloying method |
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