CN105728678A - Center porosity control method for 30CrMo circular tube blank with diameter of section being phi 280 mm - Google Patents
Center porosity control method for 30CrMo circular tube blank with diameter of section being phi 280 mm Download PDFInfo
- Publication number
- CN105728678A CN105728678A CN201610171891.6A CN201610171891A CN105728678A CN 105728678 A CN105728678 A CN 105728678A CN 201610171891 A CN201610171891 A CN 201610171891A CN 105728678 A CN105728678 A CN 105728678A
- Authority
- CN
- China
- Prior art keywords
- molten steel
- refine
- center porosity
- argon
- stirring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/114—Treating the molten metal by using agitating or vibrating means
- B22D11/115—Treating the molten metal by using agitating or vibrating means by using magnetic fields
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/12—Accessories for subsequent treating or working cast stock in situ
- B22D11/122—Accessories for subsequent treating or working cast stock in situ using magnetic fields
-
- 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
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
-
- 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
- C21C7/10—Handling in a vacuum
-
- 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
Abstract
The invention discloses a center porosity control method for producing a 30CrMo circular tube blank with the diameter of the section being phi 280 mm and belongs to the field of metallurgy. The method comprises the steps of converter steel making, LF furnace molten steel refining, RH refining, molten steel continuous casting and the like, and the method is characterized in that a technology combining crystallizer electromagnetic stirring and solidification final stage electromagnetic stirring is adopted in the continuous casting stage. The center porosity control method has the beneficial effects that firstly, the purity degree of molten steel is increased and the optimal tapping condition of the molten steel is reached according to reasonable parameter control in the molten steel smelting stage; and afterwards, in the molten steel pouring process, the mode combining crystallizer electromagnetic stirring and solidification final stage electromagnetic stirring is adopted, so that ingredients and temperature of the molten steel are uniformized, a blank shell grows uniformly, and columnar crystal structures are continuously eroded and fused in the stirring process. Accordingly, the area of a center porosity zone of the casting blank is reduced, and the compactness is improved.
Description
Technical field
The present invention relates to field of steel metallurgy, particularly relate to a kind of center porosity control method producing the 30CrMo pipe steel strand that section is φ 280mm.
Background technology
The steel for oil well pipes that 30CrMo tube blank steel uses mainly for the production of oil-gas mining, transport, chemical constituent is by weight percentage: C:0.27%～0.32%, Si:0.20%～0.35%, Mn:0.45%～0.65%, P≤0.020%, S≤0.010%, V≤0.015%, Cr::0.85%～1.05%, Mo:0.17%～0.24%, Cu≤0.15%, Ni≤0.20%, Alt:0.020%～0.040%, residual elements require: Nb≤0.010%, Ti≤0.010%, B≤0.005%, and V+Nb+Ti+B+Zr≤0.15%；As≤0.015%, Sn≤0.010%Sb≤0.010%, Pb≤0.008%, Bi≤0.010%, and As+Sn+Sb+Pb+Bi≤0.045%, surplus is Fe.In use under the combined effect of applied stress and hydrogen sulfide gas, often there is suddenly brittle failure (being called H 2 S stress corrosion) when stress is far below itself yield strength, easily cause the problems such as raw leakage, production and environmental protection are adversely affected.Along with socioeconomic development, oil gas transport efficiency requirements is higher, exploit the development trends such as difficulty increase constantly proposes harsher requirement to slab quality.Especially such as defects such as strand center porosities, much researching and analysing and point out, poling lumber recovery and end product quality are had material impact by circle base center porosity.
For 30CrMo tube blank steel, it is relatively big that the Gao Ge in steel grades, molybdenum content itself determine strand column crystal prosperity trend, furthermore, due to casting blank section is relatively large and for circle base, its specific surface area less strand heat transfer efficiency is lower, and slowly, the control of crystalline structure is more difficult in solidification cooling.In continuous casting production process, strand column crystal is flourishing, often lead to column crystal interdendritic and occur bonding, form confined space, molten steel continues cooled and solidified, volume contraction, and outside molten steel cannot feeding in time and form the defects such as loose, these defects can not all effectively eliminate in subsequent rolling process process, affects product quality.
Summary of the invention
For overcoming the 30CrMo pipe steel strand of existing relatively big cross section size the deficiencies such as center porosity easily occur, the technical problem to be solved is: provide a kind of center porosity control method for the 30CrMo pipe steel strand that section is φ 280mm.
The technical solution adopted for the present invention to solve the technical problems is:
Produce the center porosity control method of the 30CrMo pipe steel strand that section is φ 280mm, comprise the following steps:
I, converter smelting: converter terminal is controlled according to following mass percent and temperature index, aim carbon 0.05%～0.15%, terminal phosphorus≤0.010%, outlet temperature >=1670 DEG C；
II, LF stove refined molten steel: the molten steel obtained in step I carries out LF stove refine, refine whole process Argon stirs, and departures Alt is controlled according to 0.040%～0.060%, and refine continues Argon at least 5min after terminating, and out-station temperature presses 1660～1720 DEG C of controls；
III, RH refine: the molten steel obtained in step II is carried out RH refine, RH refine requires that argon flow amount controls by 1250～1550NL/min, vacuum < 3mbar, process time >=10min, RH sets off Alt according to mass percent 0.030%～0.055% control, application of vacuum continues Argon at least 5min after terminating, and out-station temperature presses 1650～1680 DEG C of controls；
IV, continuous casting steel: continuous casting link adopts the mode that M-EMS combines with solidification end electromagnetic agitation, and wherein, the parameter of M-EMS is: stir current 380～450A, 3～5Hz；Solidification end stirring parameter is: stir current 300～400A, frequency 7.0～9.0Hz.
Further, in step II and step III refining process adopt in the stirring of intensity Argon, occur without with molten steel surface and turn over greatly boiling and be as the criterion；Refine adopts soft argon blowing stirring after terminating, make molten steel have faint stirring.
It is further, also need in step IV carries out molten steel cast control following parameter: the degree of superheat controls at 25～40 DEG C, casting speed control is at 0.75～1.00m/min, and crystallizer cooling controls at 2250～2450L/min, and two cold specific waters control at 0.25～0.35l/kgSteel。
The invention has the beneficial effects as follows: first in the smelting molten steel stage according to rational state modulator, improve the degree of purity of molten steel and make its condition of setting off reach the best, subsequently in the process of pouring molten steel, adopt the mode that M-EMS combines with solidification end electromagnetic agitation, making molten steel component and equalizing temperature, green shell homoepitaxial, fusing is constantly washed away in whipping process by columanar structure, thus causing that strand center porosity region area reduces, consistency is improved.
Detailed description of the invention
Below by way of detailed description of the invention, the invention will be further described, but should not be understood as the restriction of the present invention.Those of ordinary skill in the art are according to such scheme, it is also possible to make various forms of amendment, replacement, change.Every amendment, replacement and change made based on above-mentioned technological thought broadly falls into the scope of the present invention.
Produce the center porosity control method of the 30CrMo pipe steel strand that section is φ 280mm, comprise the following steps:
I, converter smelting: converter terminal is controlled according to following mass percent and temperature index, aim carbon 0.05%～0.15%, terminal phosphorus≤0.010%, outlet temperature >=1670 DEG C；
II, LF stove refined molten steel: the molten steel obtained in step I carries out LF stove refine, refine whole process Argon stirs, and departures Alt is controlled according to 0.040%～0.060%, and refine continues Argon at least 5min after terminating, and out-station temperature presses 1660～1720 DEG C of controls；
III, RH refine: the molten steel obtained in step II is carried out RH refine, RH refine requires that argon flow amount controls by 1250～1550NL/min, vacuum < 3mbar, process time >=10min, RH sets off Alt according to mass percent 0.030%～0.055% control, application of vacuum continues Argon at least 5min after terminating, and out-station temperature presses 1650～1680 DEG C of controls；
IV, continuous casting steel: continuous casting link adopts the mode that M-EMS combines with solidification end electromagnetic agitation, and wherein, the parameter of M-EMS is: stir current 380～450A, 3～5Hz；Solidification end stirring parameter is: stir current 300～400A, frequency 7.0～9.0Hz.
Step I, II, III mainly the smelting of molten steel is controlled, it is ensured that molten steel has stable characteristic, uniform composition and suitable pouring temperature before cast.Wherein, the content of carbon and phosphorus is controlled to be to ensure that the internal soundness of molten steel by converter steelmaking process, improve its stability, LF stove refine is to make molten steel fully react, and remove unnecessary impurity, RH refine is the degree of purity in order to improve molten steel further, and makes the composition stable and uniform more of molten steel.Wherein Alt is Holo-Al content, is conducive to making the uniform small grains of steel to the control of Alt, can improve its hardenability and quenching degree and plasticity and toughness simultaneously, and when being conducive to follow-up continuous casting, strand center can form good consistency.
The present invention it is critical only that the continuous casting steel stage in step IV, it is generally the case that in continuous casting process, casting blank solidification tissue presents the crystallizer tissue regions in chill fine grained region, columnar zone, Center Equiaxial Crystal district successively from casting billet surface to center.Tissue looseness and steel ingot centre that when center porosity Producing reason is solidification of molten steel, volume contraction causes are gathered caused by field trash gathering comparatively seriously because final set makes gas analyse.For improving slab quality, it is to avoid center porosity occurs in strand, and existing mode typically just reduces impurity or slows down rate of cooling etc..The present invention thes improvement is that, employing is the mode that combines with solidification end electromagnetic agitation of M-EMS.The mechanism of action of this technology is: M-EMS produces electromagnetic torque by magnetic field, change crystallizer internal flow field of molten steel, thermo parameters method situation, promote Mold composition, equalizing temperature, weaken the directivity of solidification and heat transfer, promote green shell homoepitaxial；Further, fusing, by forcing to drive the flowing of mushy zone molten steel, is washed away by solidification end electromagnetic agitation by columanar structure, improves equiax crystal nucleation rate, finally realizes the uniform cooled and solidified in strand center, it is achieved center porosity controls.
LF stove refined molten steel and RH refining process all adopt Argon to be stirred, intensity Argon stirring in being generally adopted in refining process, occur without with molten steel surface and turn over greatly boiling and be as the criterion；Refine adopts soft argon blowing stirring after terminating, make molten steel have faint stirring.Argon stirring is primarily to and enables molten steel fully to react, and makes the composition mix homogeneously in molten steel, it is simple to follow-up can form stable solidified structure in pouring molten steel process.
Further, when carrying out the continuous casting steel stage, if solidification end electromagnetic agitation intensity controls bad, easily cause dentrite tip and wash away seriously, the low solute concentration molten steel causing the strong mobility of low melting point is assembled ringwise, form white band, it is thus desirable to its stirring intensity is accurately controlled, in addition in order to ensure last quality of becoming a useful person, also need to control following parameter when carrying out molten steel cast: the degree of superheat controls at 25～40 DEG C, casting speed control is at 0.75～1.00m/min, crystallizer cooling controls at 2250～2450L/min, two cold specific waters control at 0.25～0.35l/kgSteel.The rational degree of superheat, pulling rate match control and intensity of secondary cooling formulate the key being casting blank solidification heat transfer is controlled.
Embodiment:
Certain steel mill adopts 120t converter smelting → LF stove refine → RH refine → six machine six to flow casting machine and produces the 30CrMo circular pipe blank that section is φ 280mm.When bessemerizing end, aim carbon is 0.10% be controlled, and terminal phosphorus is 0.008%, and outlet temperature controls at 1680 DEG C.
Molten steel arrives LF refining furnace place, carries out Argon molten steel and slightly fluctuates, and does not occur turning over greatly phenomenon, and departures Alt controls to be 0.009%, and molten steel is carried out soft argon blowing after terminating by refine, and argon blowing time is after 6min, LF process terminates, and constant temperature is 1670 DEG C.
Carrying out RH refine subsequently, after molten steel arrives at a station, RH refine Argon argon flow amount is 1350NL/min control, the process time 10min of vacuum < 3mbar, RH departures Alt is 0.045%, and application of vacuum terminates rear Argon 6min, and out-station temperature controls at 1670 DEG C.
RH application of vacuum is allocated and transported after terminating and is flowed casting machine φ 280mm section to six machines six and carry out molten steel casting, and actual control of the critical technical parameter relevant to application claims is: M-EMS: stir current 400A, stirring frequency 4.0Hz；Solidification end electromagnetic agitation: stir current 350A, stirring frequency 8.0Hz；The actual casting process degree of superheat of molten steel controls at 27～35 DEG C, and pulling rate is 0.85m/min, and crystallizer cooling controls at 2350L/min, and two cold specific waters control at 0.25l/kgSteel。
After installing the operation of above-mentioned parameter stability, slab quality obtains good control, and the loose low power testing result of strand is: strand sedimentation 0.5～1.0 grade, non-densified regions area ratio 25.4%, strand in-situ metal analyzes consistency detection, and central area is 0.81.
Claims (3)
1. the 30CrMo circular pipe blank center porosity control method of φ 280mm, it is characterised in that comprise the following steps:
I, converter smelting: converter terminal is controlled according to following mass percent and temperature index, aim carbon 0.05%～0.15%, terminal phosphorus≤0.010%, outlet temperature >=1670 DEG C；
II, LF stove refined molten steel: the molten steel obtained in step I carries out LF stove refine, refine whole process Argon stirs, and departures Alt is controlled according to 0.040%～0.060%, and refine continues Argon at least 5min after terminating, and out-station temperature presses 1660～1720 DEG C of controls；
III, RH refine: the molten steel obtained in step II is carried out RH refine, RH refine requires that argon flow amount controls by 1250～1550NL/min, vacuum < 3mbar, process time >=10min, RH sets off Alt according to only carrying out mass percent 0.030%～0.055% control, application of vacuum continues Argon at least 5min after terminating, and out-station temperature presses 1650～1680 DEG C of controls；
IV, continuous casting steel: continuous casting link adopts the mode that M-EMS combines with solidification end electromagnetic agitation, and wherein, the parameter of M-EMS is: stir current 380～450A, 3～5Hz；Solidification end stirring parameter is: stir current 300～400A, frequency 7.0～9.0Hz.
2. the 30CrMo circular pipe blank center porosity control method of φ 280mm as claimed in claim 1, is characterized in that: in step II and step III refining process adopt in the stirring of intensity Argon, occur without with molten steel surface and turn over greatly boiling and be as the criterion；Refine adopts soft argon blowing stirring after terminating, make molten steel have faint stirring.
3. the 30CrMo circular pipe blank center porosity control method of φ 280mm as claimed in claim 1, it is characterized in that: also need to when carrying out molten steel cast in step IV control following parameter: the degree of superheat controls at 25～40 DEG C, casting speed control is at 0.75～1.00m/min, crystallizer cooling controls at 2250～2450L/min, and two cold specific waters control at 0.25～0.35l/kgSteel。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610171891.6A CN105728678B (en) | 2016-03-23 | 2016-03-23 | The 30CrMo circular pipe blank center porosity control methods of φ 280mm |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610171891.6A CN105728678B (en) | 2016-03-23 | 2016-03-23 | The 30CrMo circular pipe blank center porosity control methods of φ 280mm |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105728678A true CN105728678A (en) | 2016-07-06 |
| CN105728678B CN105728678B (en) | 2018-05-25 |
Family
ID=56251934
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610171891.6A Active CN105728678B (en) | 2016-03-23 | 2016-03-23 | The 30CrMo circular pipe blank center porosity control methods of φ 280mm |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105728678B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61140357A (en) * | 1984-12-11 | 1986-06-27 | Kobe Steel Ltd | Electromagnetic stirring method of weakly deoxidized steel in continuous casting of slab |
| CN101701277A (en) * | 2009-11-25 | 2010-05-05 | 天津钢铁集团有限公司 | Method for smelting steel round blank of air cylinder by convertor process |
| CN102277534A (en) * | 2011-07-29 | 2011-12-14 | 攀钢集团有限公司 | Hot rolled steel section for gas cylinders and production method thereof |
| CN105215310A (en) * | 2015-11-17 | 2016-01-06 | 攀钢集团攀枝花钢铁研究院有限公司 | A kind of method that big cross section Properties of Heavy Rail Steel strand center porosity controls |
-
2016
- 2016-03-23 CN CN201610171891.6A patent/CN105728678B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61140357A (en) * | 1984-12-11 | 1986-06-27 | Kobe Steel Ltd | Electromagnetic stirring method of weakly deoxidized steel in continuous casting of slab |
| CN101701277A (en) * | 2009-11-25 | 2010-05-05 | 天津钢铁集团有限公司 | Method for smelting steel round blank of air cylinder by convertor process |
| CN102277534A (en) * | 2011-07-29 | 2011-12-14 | 攀钢集团有限公司 | Hot rolled steel section for gas cylinders and production method thereof |
| CN105215310A (en) * | 2015-11-17 | 2016-01-06 | 攀钢集团攀枝花钢铁研究院有限公司 | A kind of method that big cross section Properties of Heavy Rail Steel strand center porosity controls |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105728678B (en) | 2018-05-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105568122B (en) | φ 280mm 30CrMo circular pipe blank center segregation control methods | |
| CN104946972B (en) | Steel disc strip for diode lead and production technology of steel disc strip | |
| CN104745765B (en) | Smelting process of Cr-Mn series spring steel | |
| CN101876024B (en) | Production method for high-chrome continuous cast billet containing N duplex stainless steel of pipe blank | |
| CN105803152B (en) | The center porosity control method of 30CrMo circular pipe blank steel strands | |
| CN105803150B (en) | The chrome molybdenum series circular pipe blank slab quality control method of φ 280mm | |
| CN105803149B (en) | The 35CrMo circular pipe blank equiaxial crystal ratio control methods of φ 280mm | |
| CN110872653B (en) | Smelting method for controlling nitrogen content in Inconel690 alloy | |
| CN105695659B (en) | The 37Mn circular pipe blank slab quality control method of φ 280mm | |
| CN111715858A (en) | Production method for realizing low-superheat-degree continuous casting | |
| CN105772666B (en) | The center segregation control method of 30CrMo circular pipe blank steel strands | |
| CN105624540A (en) | Control method of equiaxial crystal ratio of 30CrMo round pipe billet and steel casting blank | |
| CN113528976A (en) | Non-quenched and tempered bar without surface cracks and preparation method thereof | |
| CN105603301A (en) | 30CrMo circular tube billet steel casting blank internal quality control method | |
| CN105779869B (en) | The method of 30Mn circular pipe blank steel Inner Quality of Billet control | |
| CN102847898A (en) | Method for directly cast-rolling electrolytic molten aluminum | |
| CN105603300A (en) | Center segregation control method of phi280mm 35CrMo circular tube blank | |
| CN105772665B (en) | The 34CrMo pipes steel billet and its method for refining of 350 ㎜ diameters | |
| CN105803151B (en) | The 35CrMo circular pipe blank center porosity control methods of φ 280mm | |
| CN105695658B (en) | The 30CrMo circular pipe blank equiaxial crystal ratio control methods of φ 280mm | |
| CN108705050A (en) | The method that bloom continuous casting produces 34CrMo4 oxygen cylinder steel | |
| CN105568166B (en) | The 34CrMo pipes steel billet and its casting method of 350 ㎜ diameters | |
| CN109913739A (en) | The production technology of the high-quality Q195 continuous casting square billet of aircraft industry fastener | |
| CN103031488B (en) | Manufacturing method of hot rolled steel and hot rolled steel | |
| CN105728678A (en) | Center porosity control method for 30CrMo circular tube blank with diameter of section being phi 280 mm |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |