CN1167815C - Hot-rolled stainless steel annealing process under protection of full hydrogen gas - Google Patents
Hot-rolled stainless steel annealing process under protection of full hydrogen gas Download PDFInfo
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- CN1167815C CN1167815C CNB011264705A CN01126470A CN1167815C CN 1167815 C CN1167815 C CN 1167815C CN B011264705 A CNB011264705 A CN B011264705A CN 01126470 A CN01126470 A CN 01126470A CN 1167815 C CN1167815 C CN 1167815C
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Abstract
The present invention relates to hot rolling stainless steel annealing technology under the protection of full hydrogen, which is especially suitable for ferrite and martensite hot rolling stainless steel rolls for annealing processing. (a) A hydrogen gas with the hydrogen contain of more than 99.99%, the oxygen content under 10<-5> and the dew point of-60DEG C to-30DEG C is used as a protective gas for sweeping, and the dew point in the atmosphere in a furnace is controlled in-30DEG C to-50DEG C; (b) the heating and heat preservation temperature of 830 to 870DEG C is adopted; after the bottom center of a steel roll achieves the heat preservation temperature for 1 to 3 hours, the heating is stopped; (c) the steel roll is slowly cooled for 3 to 5 hours by a heating cover; then, the temperature of the bottom center of the steel roll is quickly cooled to 200 to 300 DEG C by a cooling cover, and the steel roll is discharged for naturally cooling. The technology enhances heating, cooling and production capacity and surface qualified rate and reduces operation processing cost and time.
Description
Technical field
The present invention relates to a kind of working method of hot-rolled stainless steel, be suitable for ferrite and martensite hot-rolled stainless coil of strip especially, the hot-rolled stainless steel annealing process under the perhydro gas shiled of the processing of annealing.
Background technology
Existing stainless steel manufacturer, the annealing that is used for ferrite and martensite hot-rolled stainless coil of strip is to adopt to finish in the bell furnace under the shielding gas atmosphere.The manufacturer that has adopts the hydrogen of 5-7% and the nitrogen of 95-93% to do shielding gas; because the thermal conductivity of nitrogen is low; the annealing heating and cooling time is long; though adopt 600 ℃ of tapping temperatures that the left and right sides is higher; be used to reduce cooling time; but total production cycle of table is still very long, and table throughput low (for existing technology 1).
Though the manufacturer that has also adopts 100% hydrogen to do shielding gas; because the thermal conductivity height of hydrogen; its thermal conductivity is about 7 times of nitrogen; though making the bell type annealing furnace of protection gas, annealing heating and cooling time ratio 90% above nitrogen reduces about 45%; but because of adopting the low tapping temperature about 100 ℃; prolonged cooling time, as a result total production cycle of table still very long, table throughput low (for existing technology 2).
In addition, when existing technology is annealed, do not control the water-content in the atmosphere (or dew point) in the annealing process.Therefore thicker and inhomogeneous with the coil of strip surface oxide layer after the existing technology annealing, when the next procedure pickling, at belt steel surface, comprise that length and width all produce the pickling effect that differs greatly, have coil of strip center zone of oxidation also to occur residual, and there is the phenomenon of overpickling in limit portion.For removing this surface imperfection, essentially increase treatment process, as carry out that surface grinding is handled or cleanup acid treatment once more, increased process period and production cost.
Summary of the invention
The object of the present invention is to provide the hot-rolled stainless steel annealing process under a kind of perhydro gas shiled; table throughput is improved greatly; and improved the surface quality of annealing back coil of strip, the next procedure surface acid-washing has been handled carried out easily, reduced the next procedure processing cost.
The present invention is achieved in that ferrite or the martensite hot-rolled stainless steel stacking of the hot-rolled stainless steel annealing process under the perhydro gas shiled: step a. with certainweight; lay the heating of inner cover and heating mantles, adopt in the heat-processed and contain 99.99% above hydrogen and oxygen level 10
-5Below, dew point is made protection gas at-60 ℃ to-30 ℃ hydrogen gas and is purged, and the dew point in the furnace atmosphere is controlled at-30 ℃～-50 ℃; B. adopt 830 to 870 ℃ heat tracing temperature, after coil of strip bottom centre reaches holding temperature 1-3 hour, stop heating; C. slowly cooled off 3 to 5 hours with heating mantles, with cooling cowl coil of strip bottom centre temperature is cooled fast to 200-300 ℃ again, remove cooling cowl and inner cover, the naturally cooling of coming out of the stove.
Embodiment
Below in conjunction with embodiment the present invention is described in further detail.
Processing step:
A. be 3 millimeters with 3 volume thickness, width is 1030 millimeters, and weight is 14.6 tons the shove charge of (SUS430) ferrite hot-rolled stainless steel coil of strip, stacking, lays the heating of inner cover and heating mantles, adopts in the heat-processed and contains 99.99% above hydrogen, oxygen level 10
-5Below; dew point is-50 ℃ a hydrogen gas; making protection gas purges; with the dew point hygrometer that is installed between coil of strip and inner cover; measure the dew point of gas in the purge; shielding gas purge flow rate and purge time adjust according to measured dew point, the dew point of gas in the purge are controlled at the dew point scope-40 ℃ that is beneficial to down road cleanup acid treatment operation.Be higher than the target dew point if measure dew point, then need to increase the hydrogen purge flow,, then need to reduce the hydrogen purge flow if be lower than the target dew point for measuring dew point.
B. adopt 850 ℃ heat tracing temperature,, stop heating when coil of strip bottom centre reached holding temperature after 2 hours.
C. slowly cooled off 4 hours with heating mantles, with cooling cowl coil of strip bottom centre temperature is cooled fast to 200 ℃ again, remove cooling cowl and inner cover, come out of the stove, allow coil of strip on final cooling table, lean on the air naturally cooling.
The foregoing description coil of strip is the technology contrast of example
| Annealing process | A heating mantles of a table throughput (ton/hour), a cooling cowl | Three table throughput (ton/hour) (two heating mantleses, a cooling cowl) | |||||||||
| Process system | Controlled temperature (degree) | Heat-up time (hour) | Cooling time (hour) | Heating efficiency | Cooling power | The table ability | Integration capability | Heating efficiency | Cooling power | The table ability | Integration capability |
| Existing technology 1 | 850 | 37.5 | 14 | 1.17 | 3.13 | 0.85 | 0.85 | 2.34 | 3.13 | 2.55 | 2.34 |
| Existing technology 2 | 850 | 26.5 | 18 | 1.65 | 2.43 | 0.98 | 0.98 | 3.30 | 2.43 | 2.94 | 2.43 |
| Technology of the present invention | 850 | 26.5 | 10 | 1.65 | 4.38 | 1.20 | 1.20 | 3.30 | 4.38 | 3.60 | 3.30 |
Annotate: heating efficiency=coil of strip gross weight/heat-up time cooling power=coil of strip gross weight/cooling time
Table ability=coil of strip gross weight/(heat-up time+cooling time)
Minimum value in integration capability=heating efficiency, cooling power and the table ability
The present invention is compared with prior art: 1. improved heating, cooling power, made table throughput improve 45%, 40% than existing technology 1,2 respectively; In the heat-processed because of by the dew point in the controlled atmosphere, thereby controlled oxidation makes the zone of oxidation of generation be easy to pickling in next procedure; 3. improving tapping temperature in the process of cooling is 200 ℃, and process of cooling is shortened as far as possible, has reduced zone of oxidation and oxidation inequality; So, this technology can be avoided after annealing, the iron scale that occurs during the coil of strip pickling residual and overpickling while and generation that deposit, the bad defective phenomenon of pickling, thereby improve the surface quality qualification rate after ferrite, the pickling of martensite hot rolled coil, ferrite coils of hot-rolled steel with existing technology 2 processing, its surface quality qualification rate has only about 60%, and use this processes, its surperficial qualification rate is more than 95%, therefore needn't increase treatment process for handling this surface imperfection, reduce operation processing cost and time.
Claims (2)
1. the hot-rolled stainless steel annealing process under the perhydro gas shiled is characterized in that step
A. with the ferrite or the martensite hot-rolled stainless steel stacking of certainweight, lay the heating of inner cover and heating mantles, adopt in the heat-processed and contain 99.99% above hydrogen and oxygen level 10
-5Below, dew point is made protection gas at-60 ℃ to-30 ℃ hydrogen gas and is purged; Dew point in the furnace atmosphere is controlled at-30 ℃～-50 ℃;
B. adopt 830 to 870 ℃ heat tracing temperature, after coil of strip bottom centre reaches holding temperature 1-3 hour, stop heating;
C. slowly cooled off 3 to 5 hours with heating mantles, with cooling cowl coil of strip bottom centre temperature is cooled fast to 200-300 ℃ again, remove cooling cowl and inner cover, the naturally cooling of coming out of the stove.
2. annealing process according to claim 1 is characterized in that step
A. with SUS430 ferrite hot-rolled stainless steel coil of strip stacking, lay the heating of inner cover and heating mantles, adopt in the heat-processed and contain 99.99% above hydrogen and oxygen level 10
-5Below, dew point is made the protection gas purging at-50 ℃ hydrogen gas, and the dew point in the furnace atmosphere is controlled at-40 ℃;
B. adopt 850 ℃ heat tracing temperature,, stop heating when coil of strip bottom centre reached holding temperature after 2 hours;
C. slowly cooled off 4 hours with heating mantles, with cooling cowl coil of strip bottom centre temperature is cooled fast to 200 ℃ again, remove cooling cowl and inner cover, come out of the stove, allow coil of strip on final cooling table, lean on the air naturally cooling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011264705A CN1167815C (en) | 2001-08-13 | 2001-08-13 | Hot-rolled stainless steel annealing process under protection of full hydrogen gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011264705A CN1167815C (en) | 2001-08-13 | 2001-08-13 | Hot-rolled stainless steel annealing process under protection of full hydrogen gas |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1341757A CN1341757A (en) | 2002-03-27 |
| CN1167815C true CN1167815C (en) | 2004-09-22 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNB011264705A Expired - Lifetime CN1167815C (en) | 2001-08-13 | 2001-08-13 | Hot-rolled stainless steel annealing process under protection of full hydrogen gas |
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Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102007039013B3 (en) * | 2007-08-17 | 2008-08-14 | Thyssenkrupp Steel Ag | Production process for surface-decarbonized hot-rolled strip involves making strip, heating to decarbonizing heat, retaining in carbon-free atmosphere and cooling |
| CN101812584B (en) * | 2010-05-06 | 2012-03-21 | 山西太钢不锈钢股份有限公司 | Method for blowing hydrogen in cover annealing |
| CN102312067A (en) * | 2010-07-02 | 2012-01-11 | 南通新兴特种金属材料有限公司 | Stainless steel hydrogen protective bright treatment furnace |
| EP2835432B1 (en) * | 2012-04-06 | 2016-11-02 | JFE Steel Corporation | Continuous hot-dip zinc plating facility |
| CN103276191B (en) * | 2013-06-06 | 2014-09-10 | 攀钢集团攀枝花钢钒有限公司 | Purge method for annealing of low-carbon cold-roll steel sheets |
| CN108070692A (en) * | 2017-11-30 | 2018-05-25 | 重庆徐丁科技有限公司 | A kind of steel alloy motorcycle accessories annealing process |
| CN110055381B (en) * | 2019-04-29 | 2020-08-07 | 武钢集团昆明钢铁股份有限公司 | Nitrogen protection annealing process of light-weight tool and die steel |
| CN113416821A (en) * | 2021-06-24 | 2021-09-21 | 新疆八一钢铁股份有限公司 | Annealing process for Q235-W steel grade of spiral welded pipe |
| CN114214485B (en) * | 2021-11-29 | 2022-10-11 | 辽宁石源科技有限公司 | One-fire hot charging heat treatment process for ferrite stainless steel hot-rolled plate |
| CN114410899A (en) * | 2022-02-24 | 2022-04-29 | 浦项(张家港)不锈钢股份有限公司 | Annealing production operation method of antibacterial stainless steel |
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2001
- 2001-08-13 CN CNB011264705A patent/CN1167815C/en not_active Expired - Lifetime
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| CN1341757A (en) | 2002-03-27 |
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