CN102732686A - Method for producing vanadium-nitrogen micro-alloying high-strength steel by two-step vacuum method - Google Patents
Method for producing vanadium-nitrogen micro-alloying high-strength steel by two-step vacuum method Download PDFInfo
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Abstract
The invention relates to a method for producing a vanadium-nitrogen micro-alloying high-strength steel by a two-step vacuum method, and is characterized in that a vacuum treatment process is added in a smelting process of the vanadium-nitrogen micro-alloying high-strength steel, molten steel with adjusted vanadium-nitrogen content is subjected to dehydrogenation and nitrogen increasing, the vacuum treatment process adopts a full steel ladle nitrogen bottom blowing process, a function of the vacuum smelting treatment is effectively disintegrated by the vacuum treatment process through the two-step vacuum smelting treatment method, so that the hydrogen is removed and the nitrogen is protected. By adopting the method provided by the invention, the hydrogen content of the smelted steel is lower than 1.5 ppm, the nitrogen content is controlled within 120-220 ppm, the full oxygen is controlled to be lower than 20 ppm, the extension performance qualified rate of a thick-specification steel plate with small rolling compression ratio and the thickness specification of more than 40 mm reaches more than 98%, the comprehensive performance of the vanadium-nitrogen alloying ball is improved, the use amount of the vanadium-nitrogen alloy is reduced, the pass rate of the steel plate is increased, and the cost is reduced.
Description
Technical field
The present invention relates to metallurgical steelmaking technical field, relate to a kind of method that adopts two step vacuum methodes to produce the v n micro alloying high-strength steel specifically.
Background technology
When adding micro alloying element in the steel, nitrogen is useful alloying element, and the first rope of little aurification is through forming carbon, nitride generation precipitation strength and crystal grain thinning in steel.Vanadium and nitrogen add in the steel than add separately vanadium jointly to carry out microalloying and has better strengthening effect, and this is that its strengthening effect obviously improves because the nitride of vanadium has higher stability than the carbide of vanadium, and precipitated phase is small and dispersed more.Nitrogen is a kind of effectively alloying element in the Vanadium Microalloyed Plate Steels, through making full use of cheap nitrogen element, can significantly improve the strengthening effect of Vanadium Microalloyed Plate Steels, reaches the purpose of practicing thrift the alloy consumption, reducing cost.
When steel carried out v n micro alloying, along with nitrogen content is high more, strengthening effect was also obvious more.VN alloy is applied to can carry out effective vanadium, nitrogen microalloying simultaneously in the high-strength low-alloy steel, and what promote carbon in the steel, vanadium, nitrogen compound separates out more effective performance sedimentation reinforcement and crystal grain thinning effect.In order to reach above-mentioned target, need the nitrogen content in the steel to keep higher level, increasing the motivating force that vanadium nitrogen is separated out, thereby effectively promote the vanadium nitrogen compound to separate out.
In smelting production process; The high-temp plastic of strand is relatively poor, and crack sensitivity is stronger, and the over-all properties of steel plate is difficult for guaranteeing; Especially the over-all properties qualification rate of this type of steel grade of thickness specification more than 40mm is low, has a strong impact on the lumber recovery and the delivery cycle of steel plate.At present domestic the problems referred to above are never had effective solution, a lot of factories have to confirm its guaranteed cost specification according to the s own situation of our factory that some enterprise of steel plate more than thickness specification 40mm can't guarantee its over-all properties value at all.
The basic reason that analysis causes VN alloy steel grade steel plate over-all properties not conform to; Except that the steel grade self characteristics; The centre burst that causes because of hydrogen richness is higher in its steel can't heal when rolling thick steel plates, is the another basic reason of steel plate over-all properties discord.Limited through strand slow cooling liberation of hydrogen effect; And Wasserstoffatoms is because its nucleidic mass is very little; Dispersivity in molten steel is good, have only through vacuum-treat to remove preferably, but nitrogen can together be removed when deviating from hydrogen; And the VN alloy steel grade needs the precipitation strength effect of nitrogen, so when producing the VN alloy steel grade, abandoned vacuum processing technique at present basically.Application number is 201110235702.4, and name is called a kind of low-cost RH molten steel nitrogen pick-up control nitrogen technology, and it discloses a kind of RH molten steel nitrogen pick-up control nitrogen; Adopt the operational path of " converter one ladle furnace refining one RH refining one continuous casting " to smelt, converter tapping adopts deoxidation alloying, and tapping process adds ferro-vanadium by the steel grade target value and joins vanadium; Ladle furnace carries out molten steel heating, alloy fine setting and dark desulfurization by normal process to be handled; After molten steel winched to the RH stove, RH stove lift gas was set to nitrogen, and flow is controlled according to 800-1200NL/min; Vacuumize treatment time 8-10min; Vacuum finishes the normal line feeding of laggard row, soft blow operation, can reach nitrogen in steel content in (80-120) ppm level, and final qualified molten steel pours into qualified steel billet through continuous caster.Adopt this technology, reduced composition, guaranteed nitrogen in steel content.But adopt the nitrogen content of the steel grade that this technology smelts not high; The concrete measure of high vacuum dehydrogenation is not described; And do not solve the centre burst that causes because of hydrogen richness is higher in the steel, and when rolling thick steel plates, can't heal, be the bad problem of steel plate over-all properties.Therefore, how to change thinking, the over-all properties of this type of steel grade being reformed smelting technology, raising steel plate is one of metallargist's striving direction always.
Summary of the invention
The vacuum processing technique technology that a kind of vanadium nitrogen micro-alloyed steel that provides to above deficiency is smelted can effectively solve the higher problem of hydrogen richness in the molten steel, can guarantee the nitrogen content that the VN alloy steel grade is required again simultaneously.
The technical scheme that the present invention adopted is following:
A kind of method that adopts two step vacuum methodes to produce the v n micro alloying high-strength steel; In the smelting procedure of v n micro alloying high-strength steel, increase the vacuum-treat operation; To carrying out dehydrogenation nitrogen pick-up through the adjusted molten steel of vanadium nitrogen content; Described vacuum-treat operation is taked omnidistance ladle bottom blowing nitrogen technology, and it may further comprise the steps:
The first step, ladle is hung in the vacuum-treat position, before vacuum-treat, molten steel carried out the mensuration of temperature, hydrogen richness, content of vanadium and nitrogen content, to confirm the span of control of hydrogen richness;
The span of control of second step, the hydrogen richness confirmed according to the first step is opened the ladle bottom blowing nitrogen system, and bottom blowing gas intensity carries out science under the condition that guarantees safety regulates, and starts the vacuum pattern of bleeding fast simultaneously, carries out dehydrogenated operation;
The 3rd step, with the pressure recovery of ladle to atmospheric pressure state, measure temperature, hydrogen richness, content of vanadium and the nitrogen content of molten steel, to confirm the span of control of nitrogen content;
The 4th step, carry out vacuum-treat second time, the span of control of the nitrogen content of confirming according to the 3rd step starts the low speed vacuum pattern of bleeding, and vacuum degree control is opened the ladle bottom blowing nitrogen system then at 5 ~ 8KPa, rationally regulates according to planning nitrogen increased amount.
Further, the nitrogen intensity regulation range of second in the described vacuum-treat operation in the step is 2.0 ~ 4.0NL.min
-1.t
-1
Further, the pattern of bleeding fast of the startup vacuum in second in described vacuum-treat operation step, carrying out dehydrogenated operation is that vacuum tightness reaches below the 67Pa hold-time 5 ~ 10min in 5 ~ 7min.
Further, the nitrogen intensity regulation range of the 4th in the described vacuum-treat operation in the step is 1.5 ~ 2.5NL.min
-1.t
-1, hold-time 10 ~ 15min.
Further, the vacuum processing time of the 4th in the described vacuum-treat operation in the step is 10 ~ 15min.
The beneficial effect that the present invention can reach:
(1) after the employing smelting technology technology of the present invention, hydrogen richness can reach below the 1.5ppm in the steel, and nitrogen content can be controlled in (120 ~ 220) ppm, and total oxygen can be controlled in below the 20ppm, and the over-all properties qualification rate of the high-strength steel grade of VN alloyization can reach more than 98%.It is more obvious particularly to improve over-all properties qualification rate effect at the thick steel plates of rolling compression ratio thickness specification less than normal more than 40mm.
(2) the vacuum-treat operation that the present invention adopted is applicable to VD, VOD, RH equal vacuum smelting equipment, and range of application is wider.It is to implement from the angle of dehydrogenation, control nitrogen, nitrogen pick-up and safety, stably manufactured that the present invention adopts two step vacuum methodes, and whole smelting process is safe and reliable.
(3) improve the over-all properties of VN alloy steel grade, reduced the VN alloy consumption, improved yield of steel plate, reduced cost.
Description of drawings
Fig. 1 is the ys comparison diagram of embodiment 1 and Comparative Examples.
Fig. 2 is the tensile strength comparison diagram of embodiment 1 and Comparative Examples.
Fig. 3 is the elongation comparison diagram of embodiment 1 and Comparative Examples.
Fig. 4 is the ballistic work comparison diagram of embodiment 1 and Comparative Examples.
Embodiment
Below in conjunction with concrete embodiment the present invention is done further explanation.
Embodiment 1
A kind of working method of v n micro alloying high-strength steel
Production with the high-strength steel grade AH60C-2 of the above specification 60Kg level of 40mm is example.
Adopt the smelting process for production route: converter-argon station-LF-vacuum-treat operation (VD)-continuous casting (CC).
In the LF refining procedure, add the content of vanadium in vanadium iron and the VN alloy adjustment molten steel, control to more than 0.100%, nitrogen content is by being not less than 80ppm control, and out-station temperature is by teeming temperature+60 ℃ control.The vacuum-treat operation is taked omnidistance ladle bottom blowing nitrogen technology, and it may further comprise the steps:
The first step, ladle is hung in the vacuum-treat position; Measuring temperature is 1630 ~ 1650 ℃; Hydrogen richness be (3.0 ~ 4.0) ppm, content of vanadium be 0.100 ~ 0.105% with nitrogen content be (80 ~ 120) ppm, the target of confirming dehydrogenation is that hydrogen richness drops to (1.0 ~ 1.5) ppm;
Second step, according to the hydrogen richness span of control that the first step is confirmed, open the ladle bottom blowing nitrogen system, bottom blowing gas intensity 2.0 ~ 4.0Nl.min
-1.t
-1, starting the vacuum pattern of bleeding fast simultaneously, vacuum tightness reaches in 5 ~ 7min below the 67Pa, hold-time 5 ~ 10min;
The 3rd step, with the pressure recovery of ladle to atmospheric pressure state; Measuring temperature and be 1590 ~ 1615 ℃, hydrogen richness is (1.0 ~ 1.5) ppm, sampling analysis content of vanadium 0.100 ~ 0.105% and nitrogen content (70 ~ 90) ppm, and the controlled target of confirming nitrogen pick-up is that nitrogen content is (140 ~ 220) ppm.
The 4th goes on foot, carries out the vacuum-treat second time; The span of control of the nitrogen content of confirming according to the 3rd step starts the low speed vacuum pattern of bleeding, and vacuum tightness arrives 5 ~ 8KPa in 10 ~ 15min; Open the ladle bottom blowing nitrogen system then, the bottom blowing gas intensity regulation range is generally at 1.5 ~ 2.5Nl.min
-1.t
-1, hold-time 10 ~ 15min min.
The working method of a kind of v n micro alloying high-strength steel of the present invention is applied in rolling specs on the above guaranteed cost steel grade of 40mm AH60C-2 at present; Steady running 8 months; Overall control situation: the steel grade hydrogen richness is less than 1.5ppm; Nitrogen in steel content can be stabilized in 130 ~ 180ppm, and VD nitrogen pick-up effect performance at present is stable; Entire oxygen content in the steel content is less than 20ppm.
Comparative Examples
Production with the high-strength steel grade AH60C-2 of the above specification 60Kg level of 40mm is example.
Adopt the smelting process for production route: converter-argon station-LF-continuous casting (CC).Other is all identical except the vacuum-treat operation for the processing parameter of its process control parameter and embodiment 1.
Gather eight months embodiment 1 and Comparative Examples actual production data, contrast their over-all properties.
1, ys (Rel)
Concrete data are seen accompanying drawing 1.Can obtain adopting the ys of the product that the embodiment 1 of working method of the present invention produced all qualified by accompanying drawing 1, Rel is all greater than 420N/mm
2, the ys fluctuation range broad of Comparative Examples, less stable, qualification rate 99.60%.
2, tensile strength (Rm)
Concrete data are seen accompanying drawing 2.The technology that can obtain adopting the tensile strength of the product that the Comparative Examples 1 of working method of the present invention produced obviously to be better than Comparative Examples being adopted by accompanying drawing 2.
3, elongation (A)
Concrete data are seen accompanying drawing 3.Can be obtained adopting 3 batches of elongations of appearance of product of the Comparative Examples 1 of working method of the present invention not conform to by accompanying drawing 3, it is all qualified to review; Adopt 58 batches of the product appearance of the technology of Comparative Examples not conform to, review 35 batches and do not conform to qualification rate less than 90%.
4, ballistic work (0 ℃)
Concrete data are seen accompanying drawing 4.Can obtain adopting the ballistic work of product of Comparative Examples 1 of working method of the present invention basically all qualified by accompanying drawing 4, but can find out obviously that from figure the technology back effect of adopting new technology obviously is superior to former technology.
5, concrete data contrast
Eight months embodiment 1 are done on average with Comparative Examples actual production data, and concrete data are with table 1.
Table 1 embodiment 1 and Comparative Examples actual production data
Can know by table 1, adopt the performance of products of the embodiment 1 of working method of the present invention obviously to improve.
Embodiment 2
A kind of working method of v n micro alloying high-strength steel
Stove to produce the high-strength steel grade AH60C of 25 ~ 40 mm specification 60Kg levels is an example.
Adopt the operation of converter-argon station-LF-vacuum-treat operation (VD)-continuous casting (CC).The content of vanadium that in the LF refining procedure, adds in vanadium iron and the VN alloy adjustment molten steel controls to more than 0.060%, and nitrogen content is by being not less than 80ppm control, and out-station temperature is by teeming temperature+60 ℃ control.The vacuum-treat operation is taked omnidistance ladle bottom blowing nitrogen technology, and it may further comprise the steps:
The first step, ladle is hung in the vacuum-treat position, measuring temperature and be 1620 ℃, hydrogen richness is 3.7ppm and sampling analysis content of vanadium 0.064% and nitrogen content 81ppm, and the target of confirming dehydrogenation is that hydrogen richness is 1.0 ~ 1.5ppm.
Second step, according to the hydrogen richness scope that the first step is confirmed, open the ladle bottom blowing nitrogen system, bottom blowing gas intensity 2.5NL.min
-1.t
-1, starting the vacuum pattern of bleeding fast simultaneously, vacuum tightness reaches in 6min below the 67Pa, hold-time 8min;
In the 3rd step, broken empty, measuring temperature and be 1581 ℃, hydrogen richness is 1.2ppm, sampling analysis content of vanadium 0.065% and nitrogen content 75ppm, and the controlled target of confirming nitrogen pick-up is for being not less than 80ppm control for nitrogen content;
The 4th step, carry out vacuum-treat second time, the span of control of the nitrogen content of confirming according to the 3rd step starts the low speed vacuum pattern of bleeding, and vacuum degree control reaches 8KPa in 8min, unlatching ladle bottom blowing nitrogen system, and bottom blowing gas intensity is 1.5NL.min
-1.t
-1, hold-time 5min.
Through the high-strength steel grade AH60C's of 25 ~ 40 mm specification 60Kg levels of this working method preparation.Sampling analysis, the content of vanadium in the product are 0.065%, and nitrogen content is 121ppm, and hydrogen richness is hydrogen richness 1.2ppm, and oxygen level 19ppm meets the requirement of the high-strength steel grade AH60C of 25 ~ 40 mm specification 60Kg levels.
Explanation is at last; More than set forth only unrestricted in order to technical scheme of the present invention to be described; Other modifications that those of ordinary skills make technical scheme of the present invention perhaps are equal to replacement; Only otherwise break away from the spirit and the scope of technical scheme of the present invention, all should be encompassed in the middle of the claim scope of the present invention.
Claims (5)
1. one kind is adopted two to go on foot the method that vacuum methodes are produced the v n micro alloying high-strength steel; It is characterized in that: in the smelting procedure of v n micro alloying high-strength steel, increase the vacuum-treat operation; To carrying out dehydrogenation nitrogen pick-up through the adjusted molten steel of vanadium nitrogen content; Described vacuum-treat operation is taked omnidistance ladle bottom blowing nitrogen technology, and it may further comprise the steps:
The first step, ladle is hung in the vacuum-treat position, before vacuum-treat, molten steel carried out the mensuration of temperature, hydrogen richness, content of vanadium and nitrogen content, to confirm the span of control of hydrogen richness;
The span of control of second step, the hydrogen richness confirmed according to the first step is opened the ladle bottom blowing nitrogen system, and bottom blowing gas intensity carries out science under the condition that guarantees safety regulates, and starts the vacuum pattern of bleeding fast simultaneously, carries out dehydrogenated operation;
The 3rd step, with the pressure recovery of ladle to atmospheric pressure state, measure temperature, hydrogen richness, content of vanadium and the nitrogen content of molten steel, to confirm the span of control of nitrogen content;
The 4th step, carry out vacuum-treat second time, the span of control of the nitrogen content of confirming according to the 3rd step, the startup low speed vacuum pattern of bleeding, vacuum degree control is opened the ladle bottom blowing nitrogen system then at 5 ~ 8KPa, and root carries out nitrogen pick-up.
2. a kind of method that adopts two step vacuum methodes to produce the v n micro alloying high-strength steel according to claim 1, it is characterized in that: the nitrogen intensity regulation range of second in the described vacuum-treat operation in the step is 2.0 ~ 4.0NL.min
-1.t
-1
3. a kind of method that adopts two step vacuum methodes to produce the v n micro alloying high-strength steel according to claim 1; It is characterized in that: the pattern of bleeding fast of the startup vacuum in second in described vacuum-treat operation step; Carrying out dehydrogenated operation is that vacuum tightness reaches below the 67Pa hold-time 5 ~ 10min in 5 ~ 7min.
4. a kind of method that adopts two step vacuum methodes to produce the v n micro alloying high-strength steel according to claim 1, it is characterized in that: the nitrogen intensity regulation range of the 4th in the described vacuum-treat operation in the step is 1.5 ~ 2.5NL.min
-1.t
-1, hold-time 10 ~ 15min.
5. a kind of method that adopts two step vacuum methodes to produce the v n micro alloying high-strength steel according to claim 1, it is characterized in that: the vacuum processing time of the 4th in the described vacuum-treat operation in the step is 10 ~ 15min.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102925618A (en) * | 2012-10-23 | 2013-02-13 | 鞍钢股份有限公司 | Method for increasing nitrogen of vanadium and nitrogen-containing microalloy steel |
| CN104550898A (en) * | 2014-12-27 | 2015-04-29 | 首钢总公司 | Nitrogen increment method for vanadium-nitrogen microalloying steel grade in continuous casting process |
| CN106591541A (en) * | 2016-12-23 | 2017-04-26 | 江苏沙钢集团淮钢特钢股份有限公司 | Dehydrating nitrogen increasing control method in RH vacuum treatment process |
| CN110607413A (en) * | 2019-11-01 | 2019-12-24 | 武汉钢铁集团鄂城钢铁有限责任公司 | Smelting method of low-cost high-nitrogen steel |
| CN114182065A (en) * | 2021-12-08 | 2022-03-15 | 上海电气上重铸锻有限公司 | Manufacturing method of hundred-ton-grade large steel ingot of ultralow-nitrogen silicon steel |
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| CN101613783A (en) * | 2009-08-07 | 2009-12-30 | 山西太钢不锈钢股份有限公司 | A kind of method of nitrogen pick-up in refining furnace |
| CN102399946A (en) * | 2010-09-08 | 2012-04-04 | 鞍钢股份有限公司 | Method for vacuum dehydrogenation of molten steel through VD |
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- 2012-07-05 CN CN2012102309383A patent/CN102732686A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101613783A (en) * | 2009-08-07 | 2009-12-30 | 山西太钢不锈钢股份有限公司 | A kind of method of nitrogen pick-up in refining furnace |
| CN102399946A (en) * | 2010-09-08 | 2012-04-04 | 鞍钢股份有限公司 | Method for vacuum dehydrogenation of molten steel through VD |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102925618A (en) * | 2012-10-23 | 2013-02-13 | 鞍钢股份有限公司 | Method for increasing nitrogen of vanadium and nitrogen-containing microalloy steel |
| CN104550898A (en) * | 2014-12-27 | 2015-04-29 | 首钢总公司 | Nitrogen increment method for vanadium-nitrogen microalloying steel grade in continuous casting process |
| CN106591541A (en) * | 2016-12-23 | 2017-04-26 | 江苏沙钢集团淮钢特钢股份有限公司 | Dehydrating nitrogen increasing control method in RH vacuum treatment process |
| CN106591541B (en) * | 2016-12-23 | 2018-08-28 | 江苏沙钢集团淮钢特钢股份有限公司 | A kind of dehydrogenation nitrogen pick-up control method during RH application of vacuum |
| CN110607413A (en) * | 2019-11-01 | 2019-12-24 | 武汉钢铁集团鄂城钢铁有限责任公司 | Smelting method of low-cost high-nitrogen steel |
| CN114182065A (en) * | 2021-12-08 | 2022-03-15 | 上海电气上重铸锻有限公司 | Manufacturing method of hundred-ton-grade large steel ingot of ultralow-nitrogen silicon steel |
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Application publication date: 20121017 |