CN107614153A - Melt surface processing titanium plate base and the titanium material for hot rolling for having used the titanium plate base - Google Patents
Melt surface processing titanium plate base and the titanium material for hot rolling for having used the titanium plate base Download PDFInfo
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- CN107614153A CN107614153A CN201680031125.8A CN201680031125A CN107614153A CN 107614153 A CN107614153 A CN 107614153A CN 201680031125 A CN201680031125 A CN 201680031125A CN 107614153 A CN107614153 A CN 107614153A
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- oxygen concentration
- plate base
- titanium
- titanium plate
- slab
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- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 title claims abstract description 171
- 239000010936 titanium Substances 0.000 title claims abstract description 170
- 229910052719 titanium Inorganic materials 0.000 title claims abstract description 169
- 238000012545 processing Methods 0.000 title claims abstract description 138
- 238000005098 hot rolling Methods 0.000 title claims abstract description 114
- 239000000463 material Substances 0.000 title claims description 30
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 324
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 323
- 239000001301 oxygen Substances 0.000 claims abstract description 323
- 238000007711 solidification Methods 0.000 claims abstract description 73
- 230000008023 solidification Effects 0.000 claims abstract description 73
- 238000005266 casting Methods 0.000 claims abstract description 70
- 239000002184 metal Substances 0.000 claims abstract description 61
- 229910052751 metal Inorganic materials 0.000 claims abstract description 60
- 238000000034 method Methods 0.000 claims abstract description 50
- 238000004519 manufacturing process Methods 0.000 claims abstract description 25
- 238000005096 rolling process Methods 0.000 claims abstract description 16
- 239000011261 inert gas Substances 0.000 claims abstract description 7
- 229910052793 cadmium Inorganic materials 0.000 claims abstract description 3
- 238000005520 cutting process Methods 0.000 claims description 25
- 238000005097 cold rolling Methods 0.000 abstract description 29
- 230000015572 biosynthetic process Effects 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 199
- 238000002844 melting Methods 0.000 description 64
- 230000008018 melting Effects 0.000 description 64
- 238000011109 contamination Methods 0.000 description 45
- 238000009826 distribution Methods 0.000 description 37
- 238000000605 extraction Methods 0.000 description 37
- 238000010894 electron beam technology Methods 0.000 description 27
- 230000008569 process Effects 0.000 description 26
- 238000009740 moulding (composite fabrication) Methods 0.000 description 21
- 229910000831 Steel Inorganic materials 0.000 description 18
- 239000010959 steel Substances 0.000 description 18
- 239000000155 melt Substances 0.000 description 17
- 208000037656 Respiratory Sounds Diseases 0.000 description 14
- 230000008859 change Effects 0.000 description 14
- 239000007789 gas Substances 0.000 description 14
- 238000005554 pickling Methods 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 13
- 238000003754 machining Methods 0.000 description 13
- 238000001816 cooling Methods 0.000 description 12
- 238000010586 diagram Methods 0.000 description 10
- 238000010438 heat treatment Methods 0.000 description 10
- 239000002994 raw material Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 230000007547 defect Effects 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000002344 surface layer Substances 0.000 description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 5
- 229910052802 copper Inorganic materials 0.000 description 5
- 239000010949 copper Substances 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 230000004927 fusion Effects 0.000 description 5
- 230000035515 penetration Effects 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 238000000137 annealing Methods 0.000 description 4
- 238000011835 investigation Methods 0.000 description 4
- 238000003723 Smelting Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 239000004744 fabric Substances 0.000 description 3
- 238000005242 forging Methods 0.000 description 3
- 230000001678 irradiating effect Effects 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 238000005482 strain hardening Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- XWROUVVQGRRRMF-UHFFFAOYSA-N F.O[N+]([O-])=O Chemical compound F.O[N+]([O-])=O XWROUVVQGRRRMF-UHFFFAOYSA-N 0.000 description 2
- 238000004125 X-ray microanalysis Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000004453 electron probe microanalysis Methods 0.000 description 2
- 230000008520 organization Effects 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000013000 roll bending Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- WWYNJERNGUHSAO-XUDSTZEESA-N (+)-Norgestrel Chemical compound O=C1CC[C@@H]2[C@H]3CC[C@](CC)([C@](CC4)(O)C#C)[C@@H]4[C@@H]3CCC2=C1 WWYNJERNGUHSAO-XUDSTZEESA-N 0.000 description 1
- 229910000906 Bronze Inorganic materials 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000010974 bronze Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000004581 coalescence Methods 0.000 description 1
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000008034 disappearance Effects 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 238000004093 laser heating Methods 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/02—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling heavy work, e.g. ingots, slabs, blooms, or billets, in which the cross-sectional form is unimportant ; Rolling combined with forging or pressing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
-
- 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
-
- 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
- B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
- B22D11/041—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds for vertical casting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K15/00—Electron-beam welding or cutting
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C14/00—Alloys based on titanium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
- C22F1/18—High-melting or refractory metals or alloys based thereon
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Metal Rolling (AREA)
- Continuous Casting (AREA)
- Welding Or Cutting Using Electron Beams (AREA)
Abstract
The present invention provides a kind of processing of melt surface and use titanium plate base, and it is the surface formation depth d in the titanium plate base that as-cast condition is handled made from the DC slab casting methods under by vacuum or inert gas atmosphere, maintained using melt surface1Remelted solidification layer and by using the surface as the hot rolling of rolling surface to manufacture titanium when use, wherein, on the thickness direction of the titanium plate base, d (is played in the 1st region from the surface1Region untill/2 position) in average oxygen concentration relative to the average oxygen concentration of the mother metal of the titanium plate base increment C1For below 0.20mass%, the 2nd region is (from the d1Play the d in/2 position1Position untill region) in average oxygen concentration relative to the average oxygen concentration of the mother metal of the titanium plate base increment C2For below 0.05mass%, Cd(=C1- C2) it is more than 0 and be below 0.15mass%.Melt surface processing uses the processability aspect in the cold rolling or cold forming of titanium plate base after hot rolling excellent.
Description
Technical field
Implement surface the present invention relates to the titanium plate base of the melt surface processing formed by industrial pure titanium and to the slab
The titanium blank for the hot rolling that melt process forms.
Background technology
In general, as industrial pure titanium, generally considered to be worth doing with the titanium sponge, the titanium that are obtained by kroll process as melting raw material,
Using having used the high density thermal energy sources such as vacuum arc melting (VAR), electronic torch melting (EBR) or plasma arc melting
Smelting process carry out melting and be formed as large-scale strand (ingot casting).Herein, as casting blank shape, in the feelings of vacuum arc melting
Under condition, columned strand (circle ingot casting (billet)) is defined in, on the other hand, is melted in electronic torch melting, plasma arc
In the case of refining, the strand of rectangular in form, i.e. slab can be cast.
And then when manufacturing titanium sheet metal using such large-scale strand as blank, in general, as needed to large-scale
After strand carries out the cutting finishing on surface, by implementing breaking down or forging, the hot rolling being processed into after being suitable in hot-working
Shape, the hot rolling blank of size.The hot procedure based on these breaking down or forging is referred to as cogging process herein
(breakdown step).Moreover, in order to further remove the hot rolling after cogging with the oxidation formed on the superficial layer of blank
Nitride layer, oxygen coalescence layer, generally superficial layer is pruned to more than a few mm degree using machining, close to after 10mm, be supplied to heat
Roll.
However, in so conventional in general method, for being processed into the shape for being suitable for hot rolling, chi from large-scale strand
Very little breaking down or the cogging process of forging need plenty of time and cost, and this is improved to the productivity ratio that titanium sheet metal manufactures, cost drops
It is low to turn into big bottleneck.
Recently, large-sized casting ingot casting is substituted, the slab shape strand relatively thin as manufacture, that is, has and can directly be supplied to
The shape of hot rolling, the method for the strand of size and gradually establish the technology of DC (direct pouring) slab casting method.DC slabs are cast
The method of making is following method：The titanium liquation melted using electronic torch melting or plasma arc melting in siege is continuously noted
Enter to remaining in vacuum or inert gas atmosphere, predetermined shape water cooling Copper casting mould, and will be coagulated in the water cooling Copper casting mould
Consolidate part continuously extracted out from the lower end side of mold, obtain the slab shape strand of predetermined length.
If using the DC slab casting methods, the cogging process needed in the past can be omitted, as a result, titanium can be improved
The productivity ratio of thin plate manufacture simultaneously reduces manufacturing cost.
However, (below, it is also referred to " DC slabs " for the slab obtained by the DC slab casting methods.), generally, slab
The bumps on top layer are serious and defect is more.If such strand is directly supplied into hot rolling, the plate (hot rolled plate) after hot rolling
Surface texture be deteriorated.Therefore, actual conditions are, before hot rolling, it has to implement several mm to 20mm or so cutting to surface
Processing.Thus, the yield rate of material reduces, and additionally needs time, the cost of machining, therefore improved requirement is still strong
It is strong.
Moreover, in the case of hot rolling is supplied to after implementing surface cut processing to DC slabs, after hot rolling
The surface texture of hot rolled plate may not become the problem of good.That is, there are the following problems：Size is largely produced in hot rolling plate surface to reach
Lid (the Japanese of length to several mm to 10mm or so：By さ り shapes) flaw.The surface blemish of such hot rolled plate comes from
The thick cast sturcture of the slab cast.That is, without the hot rolling as hot worked cogging process with blank have comprising
Maintain state (as cast during casting；" maintaining state during casting ") thick crystal grain including cast sturcture, i.e.,
Make to implement its surface machining, there is also thick tissue on the superficial layer after cutting, due to so thick surface
Cast sturcture causes to produce surface blemish on hot rolled plate.
However, for without titanium material for hot rolling obtained from cogging process, in order to prevent the hot rolling after hot rolling
The surface blemish occurred in plate surface, it has been proposed that implement the method for modification to superficial layer in advance before hot rolling.
Such as following method is proposed in patent document 1：Surface to titanium plate base, especially turn into rolling surface in hot rolling
Side surface using high-frequency induction heating, electric arc heated, plasma arc heating, electron beam heating or laser heating etc.
High-energy is assigned, its superficial layer is melted to more than 1mm depth, even if its quenching of existing side by side solidifies again.
Using such method, the superficial layer of titanium plate base melts, so that being smoothed of surface, and the stomata in superficial layer
The defects of disappear, further, since by the heat extraction from mother metal side and make melting layer be quenched and solidify while, the hot shadow of downside
Ring layer (HAZ layers) to be quenched, melting layer and HAZ layers turn into small phase-change organization.Moreover, the superficial layer of so microminiaturization exists
Recrystallized during heating of plate blank before hot rolling afterwards, it is (isometric to turn into small and with irregular orientation granular tissue
Grain structure).Therefore, it is possible to prevent the depression caused by thick tissue, the hot rolled plate after hot rolling can be also eliminated
Surface blemish.
In addition, in this manual, by by assigning high-energy to the surface of titanium plate base as described above and only making surface
Even if layer melting, its quenching solidification of existing side by side are referred to as at melt surface so as to be modified the method for processing to the superficial layer of titanium plate base
Reason.In addition, in this manual, melt surface processing will be utilized to make, and superficial layer melts and then the melting layer is concretionary again
Layer is referred to as remelted solidification layer.Also, in this manual, by the material (slab) of the hot rolling after implementation melt surface processing
Referred to as hot rolling blank.
Prior art literature
Patent document
Patent document 1：Japanese Unexamined Patent Publication 2007-332420 publications
The content of the invention
Problems to be solved by the invention
In addition, for the hot-finished material obtained from hot rolling is carried out after implementing melt surface processing to DC slabs, it is general next
Say, cold rolling is implemented to it afterwards and the hot-finished material is turned into the thickness corresponding with product-use.According to circumstances, sometimes also
The cold formings such as bending, drawing, stretching processing can be implemented.After even if use implements melt surface processing using DC slabs as original material
Hot rolling blank, in cold rolling after hot rolling, cold forming processing, surface can also crack sometimes.Production for the problem
Various experimental studies have been repeated in raw reason, the present inventor etc., and as a result having understood fully it is caused by phenomenon as following
's.
That is, first confirm that, the face crack in cold rolling as described above, cold forming processing is significantly enriched in heat in oxygen
Easily produced in the case of rolling plate surface layer.That is, the oxygen concentration inside the oxygen concentration of hot rolling plate surface higher layer and hot rolled plate
Larger difference generally be present in the cold-workability in relatively low region, it can be seen that, due to the difference of such oxygen concentration, in cold rolling
When, cold forming when, easily cracked in the superficial layer of high oxygen concentration.
Experimental study further has been carried out to the enrichment reason of the oxygen of such hot rolled plate superficial layer, understood fully therewith, this
It is caused in DC slab casting processes, and melt surface processing afterwards can also impact to the distribution of oxygen concentration.
That is, understood fully superficial layer in DC slabs occasionally there are with very high concentration (for example, playing depth 0.5mm from surface
Untill the average oxygen concentration of part be oxygen concentration higher 0.3mass%~0.5mass% than the average oxygen concentration of mother metal or so)
Containing aerobic layer (calling it as oxygen contamination layer below).So oxygen contamination layer is produced it is conceivable that several reasons in steel slab surface,
As one of reason, alternatively it is conceivable to, when in order to which fluid origin slab is opened into chamber from chamber taking-up is extracted out after casting,
The air entered from outside is absorbed by steel slab surface sometimes.In addition, it is contemplated that the chamber in casting be present for some reason
Vacuum around indoor vacuum, the slab for the high temperature especially extracted out from mold does not uprise fully or indifferent gas
The situation that residual oxygen-containing gas concentration under body atmosphere uprises, in these cases, oxygen is sometimes from the atmosphere around slab
Absorbed by steel slab surface.
Also, if the slab of oxygen contamination layer will be so generated on surface on the premise of surface cut processing is not implemented
Melt surface processing is just supplied to, then the higher state of oxygen concentration can be handled by melt surface and extend to remelted solidification dearly
The entire depth direction of layer, if further heated using the slab as hot rolling with blank, the oxygen of remelted solidification layer
Concentration can only be uprised and will not reduced, and thicker oxygen contamination layer is also remained on hot rolled plate after hot rolling, and (oxygen concentration is higher to be melted again
Melt solidification layer).It is contemplated that also failing to fully remove in pickling of such deeper oxygen contamination layer before cold rolling, and understand
It left behind, if the hot rolled plate is supplied into cold rolling, cold forming, due to the oxygen close to the region (remelted solidification layer) on surface
The difference of cold-workability caused by the difference of the oxygen concentration of concentration and interior zone, is easily cracked.
Herein, in the case of the state when DC slabs maintain casting, generally, the oxygen concentration of superficial layer (oxygen contamination layer)
With going to become big such gradient (oxygen concentration gradient) from private side towards surface, but observe, if at using melt surface
Reason melt-solidifies superficial layer again, then the oxygen concentration in the remelted solidification layer (oxygen contamination layer) realizes equalization, concentration ladder
Degree disappears, and in the layer, in the part untill playing surface from inner side, oxygen concentration turns into constant.But under the state
Constant oxygen concentration after equalization apparently higher than than remelted solidification layer (oxygen contamination layer) close to the inner portion side uncontamination region (not
The region of the holding raw sheet billet state melt-solidify again) oxygen concentration.It means that the plate after melt surface processing
Superficial layer (remelted solidification layer in base (hot rolling blank)；Oxygen contamination layer) and than between the superficial layer close to the inner portion region of side
Border near, oxygen concentration sharp changes in step-like.
It is in hot rolling blank after such melt surface processing (melting-solidify processing again), superficial layer is (remelted
Solidification layer) drastically the changing in the heating of plate blank before hot rolling for oxygen concentration near border between interior zone do not eliminate,
The state is also maintained after hot rolling.In addition, as it was previously stated, being handled by melt surface, oxygen contamination layer is deepened and reached in hot rolling
The depth that can not be removed in the pickling of plate.Therefore, it is possible to expect, in cold rolling after pickling, cold forming, due to superficial layer (again
Melting and solidification layer) significant cold-workability near border between interior zone difference, be nearby with the border easily
Starting point cracks.That is, it can be seen that, the melt surface carried out to hot rolling with blank (slab) is handled for making smooth surface
Change, make the defects of superficial layer (stomata etc.) disappearance aspect be extremely effective, but in the case where superficial layer is by oxygen contamination, can make
Into the equalization (oxygen concentration for making to go from inner side towards surface homogenizes) of the oxygen concentration in the pollution layer and adding for oxygen contamination layer
Deep (the higher region of oxygen concentration expands in the depth direction), this easily causes crackle when cold rolling, cold forming as described above
Problem.
Even in addition, DC slabs, the superficial layer of the strand of state when maintaining casting be generally also it is concavo-convex serious and
Layer more than defect.In the past, additionally it is possible to expect, using machining to remove slab in a manner of being removed to several mm or so depth
Superficial layer after, implement the processing of foregoing melt surface.In this case cutting using remove the bumps on surface, defect as
Main purpose, but be also contemplated that, this method is copied, the oxygen contamination layer of DC steel slab surfaces is removed using machining, afterwards
Implement melt surface processing.So, if advancing with machining in melt surface before processing removes desurfacing (oxygen contamination
Layer), then it can avoid cracking problem in cold working, cold forming because of oxygen contamination when foregoing DC is cast.
However, the oxygen concentration of the oxygen contamination layer in DC slabs is higher and the depth of oxygen contamination layer relatively depth in the case of, cut
Cut depth to also have to deepen, in this case, surface cut processing needs a large amount of time and time, yield rate also to drop significantly
It is low.Thus, if omit as melt surface before processing machining or at least make cutting depth shallower, can prevent
Oxygen contamination when being cast because of foregoing DC and cracked in cold rolling, cold forming, can be with high production rate and low cost
To manufacture the excellent titanium sheet metal of cold-workability.
Thus, problem of the invention is, there is provided makes in the machining without melt surface before processing or at least table
In the case that the cutting depth of machining before the melt process of face is shallower, can be cold after melt surface processing-hot rolling
Roll, be reliable in cold forming and stable against the melt surface processing titanium plate base cracked on surface and used the slab
Melt surface processing after the completion of titanium material for hot rolling, and then can improve titanium hot rolled plate manufacture productivity ratio and seek cost
Reduce.
The solution used to solve the problem
In order to solve above-mentioned problem, the present inventor etc. gos deep into experimental study, as a result found repeatedly：If at melt surface
The stage of titanium plate base before reason makes the oxygen concentration gradient on the slab thickness direction of the superficial layer moderately reduce in advance, then can
Solves foregoing problem, so as to complete the present invention.
Therefore, basic technical scheme (the 1st technical scheme) of the invention provides a kind of melt surface processing and uses titanium plate base,
It is to form depth d on the surface of titanium plate base using melt surface processing1Remelted solidification layer and by with the surface
For rolling surface hot rolling to manufacture titanium when use, wherein, the titanium plate base is by under vacuum or inert gas atmosphere
DC slab castings method is obtained, maintains the titanium plate base of as-cast condition, will be from the table on the thickness direction of the titanium plate base
Play d in face1Region untill/2 position is set to the 1st region, will be from the d1Play the d in/2 position1Position untill
Region is set to the 2nd region, the average oxygen concentration by the average oxygen concentration in the 1st region relative to the mother metal of the titanium plate base
Increment be set to C1, by the average oxygen concentration in the 2nd region relative to the average oxygen concentration of the mother metal of the titanium plate base
Increment is set to C2, by C1With C2Between poor C1- C2It is set to Cd, now, C1For below 0.20mass%, C2For 0.05mass% with
Under, and CdMore than 0 and it is below 0.15mass%.
Also, the 2nd technical scheme of the present invention is the base in the melt surface processing titanium plate base of the 1st technical scheme
On plinth, the CdFor below 0.10mass%.
Also, the 3rd technical scheme of the present invention is the melt surface processing titanium in the 1st or the 2nd technical scheme
On the basis of slab, the d1In the range of 3.0mm~10.0mm.
In addition, the 4th technical scheme of the present invention is in any one of the technical scheme of the 1st technical scheme~the 3rd technology
On the basis of titanium plate base is used in the melt surface processing of scheme, the surface is eliminated with below 3.0mm thickness cutting.
Also, in the technical scheme of the 5th following technical scheme~the 7th, to by melt surface as described above
The processing (melt surface processing) that reason implements the melting based on high density energy-rapidly solidify again with the surface of titanium plate base forms
Titanium material for hot rolling provided.
That is, the 5th technical scheme of the invention provides a kind of titanium material for hot rolling, wherein, the titanium material for hot rolling is in profit
Handled with melt surface and form depth on the surface of the titanium plate base of any one of the technical scheme of the 1st technical scheme~the 4th technical scheme
Spend d1Remelted solidification layer and by using the surface as the hot rolling of rolling surface to manufacture titanium when use.
In addition, the 6th technical scheme of the present invention is the thickness side on the basis of the titanium material for hot rolling of the 5th technical scheme
Upward oxygen concentration is distributed in boundary position between the remelted solidification layer and mother metal from mother metal towards surface in step-like
Increase.
In addition, the 7th technical scheme of the present invention is in any one of the 5th technical scheme and the 6th technical scheme technology
On the basis of the titanium material for hot rolling of scheme, the average oxygen concentration of the remelted solidification layer relative to the mother metal averaged oxygen
The increment of concentration is below 0.1mass%.
The effect of invention
Using the present invention, handled using melt surface and remelted solidification layer is formed on the surface of titanium plate base, and by with institute
Hot rolling that surface is rolling surface is stated to be made hot rolled plate, and then after implementing the processing of the descales such as pickling to the hot rolled plate,
When implementing cold forming processing when implementing the cold working such as cold rolling or after cold rolling and annealing, the processing such as crackle can be prevented not
It is good.Also, this present invention is used, even if not implementing machining to steel slab surface in melt surface before processing or even if making this
Cutting output is smaller, can also prevent it is as described above the bad situation of processing such as implementing to crack during cold working, accordingly, it is capable to
It is enough to omit cutting or reduce cutting output, therefore, it is possible to seek the raising of productivity ratio, the reduction of manufacturing cost.
Brief description of the drawings
Fig. 1 is schematically shown using the DC castings under vacuum to manufacture the simple of the method for titanium plate base example
Schematic diagram.
Fig. 2 is the schematical stereogram for representing to implement titanium plate base one example of the situation of melt surface processing.
Fig. 3 is an example of the situation for being directed to titanium slab surface layer when implementing melt surface processing to titanium plate base at it
The schematic diagram that sectional position is indicated.
Fig. 4 is accordingly to represent to maintain the thickness direction at the sectional position of the titanium plate base of as-cast condition with slab section
On oxygen concentration distribution an example schematic diagram.
Fig. 5 A are the oxygen concentration distributions on the thickness direction at the sectional position as the titanium plate base for maintaining as-cast condition
An example and by the schematic diagram of Fig. 4 IV portions enlarged representation.
Fig. 5 B are to represent to carry out titanium plate base stage after melt surface processing, become rank after hot rolling blank
The schematic diagram of one example of the oxygen concentration distribution on thickness direction in section, at sectional position.
Fig. 5 C are to represent to carry out titanium plate base thickness in the stage after melt surface processing and hot rolling, at sectional position
The schematic diagram of one example of the oxygen concentration distribution spent on direction.
Fig. 5 D are to represent to carry out titanium plate base in the stage after melt surface processing and hot rolling and pickling, section
The schematic diagram of one example of the oxygen concentration distribution on the thickness direction of opening position.
Fig. 6 A are to represent to maintain the thickness at the sectional position of the titanium plate base of as-cast condition with Fig. 5 A identicals scales
The schematic diagram of the comparative example for the oxygen concentration distribution spent on direction.
Fig. 6 B are to represent to carry out titanium plate base the oxygen concentration point after melt surface processing with Fig. 6 A identicals scales
The schematic diagram of the comparative example of cloth.
Fig. 7 is by the oxygen concentration distribution on the thickness direction at the sectional position of the titanium plate base of the present invention and melt surface
One example of the concentration distribution after reason with the oxygen concentration of the conventional titanium plate base with oxygen contamination layer distribution and melt surface
The schematic diagram shown in mode that concentration distribution after processing is contrasted.
Embodiment
Below, embodiments of the present invention are explained referring to the drawings.
First, before explanation melt surface processing of the invention is with titanium plate base, for manufacturing melt surface processing titanium
Even if the method for slab, with the high density energy such as electron beam or plasma thermal source under vacuum or inert gas atmosphere melting titanium
Melting raw material and the DC slab casting method (direct pourings that the strand (slab) of rectangular in cross-section shape is continuously cast with predetermined length
Method), reference picture 1 illustrates to apply the example in the case of electronic torch melting.
In Fig. 1, in cast titanium slab 10, by the melting raw material of industrial pure titanium, for example obtained by kroll process
Titanium sponge, pure titanium bits are supplied to the water cooling copper siege 2 being disposed in melting chamber 1, are irradiated using electron beam irradiation rifle 12
Electron beam 3 makes the melting raw materials melt in siege 2.Then, obtained titanium liquation 4 is continuously poured into DC slab castings
Water cooling Copper casting mould 6, i.e. the water cooling casting in bronze of opening and the rectangular shape in horizontal cross-section (including corner the situation formed with chamfering) up and down
In mould 6, the water cooling Copper casting mould 6 of the DC slab castings is disposed in the top of casting-extraction chamber 5.In addition, now, it is general next
Say, in order to keep the temperature on the surface of the titanium liquation 4 in mold 6, in addition to the electron beam 3 of melting, also in mold 6
The surface irradiating electron beam 7 of titanium liquation 4.In addition, the siege 2 for being occasionally used for melting melting raw material is multiple or multistage.
Under extraction member (receiving member that can be lifted) 8 by the lower section for making to be disposed in casting-extraction chamber 5
Drop, so as to which the titanium of the solidification in mold 6 is continuously extracted out downwards, thus, obtained in the extraction chamber 5B described as follows
Rectangular cross-section (including corner the situation formed with chamfering) and be the titanium plate base 10 of predetermined length.
Herein, casting-extraction chamber 5 turns into the casting chamber 5A that will surround mold 6 and the extraction chamber of the lower section of mold 5
Room 5B connects the structure of setting in the vertical direction, and the extraction chamber 5B of bottom is configured to sometimes, completes the casting of predetermined length
Leave the casting chamber 5A on top after making, and together with extraction member 6 from original position (position during casting) to side (such as
Fig. 1 left) it is mobile.In this case, in general, in order to keep casting chamber 5A vacuum state, to casting chamber 5A
Type variable demarcation strip (valve plate) (not shown) is inserted between extraction chamber 5B or is set has type variable demarcation strip (valve plate)
Shorter lock chamber.In addition, be configured to, the opposite side of the position (original position) for extracting chamber 5B out in casting (such as Fig. 1
Right) another extraction chamber (chamber with another extraction member) (not shown) is equipped, complete the titanium plate of predetermined length
After the casting of base 10, moved with the extraction chamber 5B of original position to side (such as Fig. 1 left), above-mentioned another extraction chamber
Room reaches casting chamber 5A downside.
In addition, herein, in the case where type variable demarcation strip (valve plate) is opened, space and casting in melting chamber 1-
The space extracted out in chamber 5 is connected by space around mold 6 etc..Also, on the top of such as melting chamber 1, borrow
Exhaust-assisting pipe 9a is connected with vavuum pump 9, to be carried out to the space in the space in melting chamber 1 and casting-extraction chamber 5
Vacuum exhaust.Thus, the melting and casting of titanium is substantially what is carried out under vacuum exhaust.But in fact, it can also lead sometimes
Enter the thin inert gas of very small amount.
The casting of the titanium plate base 10 of predetermined length is completed in casting-extraction chamber 5 as described above, and is placed some
Time and titanium plate base 10 is carried out a certain degree of cooling, insert type variable demarcation strip afterwards, the extraction chamber 5B of bottom leaves
The casting chamber 5A on top simultaneously moves to such as Fig. 1 left together with titanium plate base 10 and extraction member 6, so as to complete 1 batch
Melting and casting.When the extraction chamber 5B of bottom so leaves the casting chamber 5A on top and moves, chamber 5B is extracted out
Interior vacuum exhaust is interrupted, and after appropriate temperature is further cooled to, is extracted chamber 5B out and is opened under atmospheric pressure.
At the same time or afterwards, such as another extraction chamber positioned at right side (has another extraction member, carried out in advance
The extraction chamber of vacuum exhaust) casting chamber 5A lower position is moved to, the extraction chamber is connected to casting chamber 5A, then
It is secondary to open type variable demarcation strip, it is connected in melting chamber 1 and casting-extraction chamber 5 with melting chamber 1, utilizes vavuum pump 9
It is exhausted, in case the melting and casting of next batch.
Next, reference picture 2, Fig. 3 illustrate to implement the titanium plate base 10 obtained by foregoing melting and casting
The example of the method for melt surface processing.
For example, as shown in Fig. 2 in the titanium plate base 10 with chamfering 11, along its length direction (in DC slab castings
Strand extraction direction) LD extensions 4 face 10A~10D in wider two face 10A, 10B face of chamfering 11 (have) turn into
Rolling surface during hot rolling.Therefore, melt surface processing at least is implemented to wider two face 10A, 10B with the chamfering 11.
It is of course also possible to it is that melt surface processing not only is implemented to wider two faces 10A, 10B, also side 10C, 10D also carried out
Melt surface processing, thereby, it is possible to enjoy the advantages of omitting cutting etc., but herein, is set to enter wider two faces 10A, 10B
Row melt surface handles and deploys to illustrate.
Specifically, first, using electron beam irradiation rifle 13 to the wider 1 face 10A in the outer surface of titanium plate base 10
Surface irradiating electron beam, face 10A superficial layer is rapidly melted.Now, while making electron beam irradiation rifle 13 continuously
It is mobile or continuously move rectangular casting blank 10, while making length direction LD of the melting position along titanium plate base 10 (or short
Edge direction) continuously move.The melting layer on the surface of titanium plate base 10 now is represented using reference 16a in figure 3.
If make electron beam irradiation rifle 13 relative to titanium plate base 10 relatively continuous moving while carrying out electron beam
Irradiation, then as shown in Figure 3, the melting layer 16a for completing the part after irradiation can be by from mother metal (inside of titanium plate base 10)
Heat extraction and be cooled, if reached below setting temperature, melting layer 16a can solidify and turn into remelted solidification layer 20.
Further, since the heat affecting of melt surface processing, produces the hot shadow being heated to more than beta transformation point temperature (about 900 DEG C)
Sound portion (HAZ) 18.Afterwards, the heat affected zone (HAZ) 18 is cooled by the heat extraction from mother metal (inside of titanium plate base 10), is made
The heat affected zone (HAZ) 18 reaches below beta transformation point temperature, so as to form heat affected layer 22.
In this manual, the remelted solidification layer 20 and heat affected layer 22 are referred to as melt surface process layer 21 in the lump.
Also, if the melting of the whole region (or needing region to be processed) of 1 face 10A for titanium plate base 10-
The processing (melt surface processing) solidified again terminates, then carries out processing similar to the above to the another side 10B of titanium plate base 10.And
And as needed, identical processing is also carried out to other face 10C, 10D of titanium plate base 10.
Herein, in the processing of above-mentioned melt surface, the surface irradiating electron beam to titanium plate base, if the surface be heated to
The temperature more than fusing point (be usually 1700 DEG C or so) of industrial titanium, then the plate face 10A of titanium plate base 10 superficial layer be melted
To depth corresponding with heat input.That is, depth d in a thickness direction is played from surface1Position untill region be melted,
Pass through solidifying again to form depth d in a thickness direction afterwards1Remelted solidification layer 20.In addition, it is also formed with depth d2's
Heat affected layer 22.Thus, handled by such melt surface, thick cast sturcture is transformed into the whole of small phase-change organization
The depth of individual region (melt surface process layer 21) is d (=d1+d2)。
In addition, the depth of fusion penetration, namely remelted solidification layer 20 based on melt surface as described above processing
d1Generally in the range of 3mm~10mm.
Fusion penetration based on electron beam irradiation mainly has relation with heat input, therefore with above-mentioned molten as that can obtain
Melt depth d1The mode of such heat input, select electron beam irradiation condition.In fact, thickness (the thermal capacitance according to slab
Amount), slab mother metal temperature, the cooling condition etc. of slab mother metal side, required heat input is also different, therefore, for obtaining
Stating the heat input of fusion penetration can not unify to determine, but generally by per unit area (per 1cm2) heat input be set to 80J
~300J or so.In addition herein, the electron beam irradiation condition as the heat input for influenceing per unit area, there is the defeated of irradiation rifle
Go out power and beam diameter, also continuously move as mentioned above irradiation rifle while rifle movement when being irradiated is fast
(irradiation position translational speed) etc. is spent, suitably they are set and ensures above-mentioned heat input.
Be carried out as described above melt surface processing titanium plate base as hot rolling blank by appropriate heating stove heat
To more than hot rolling start temperature, then, the hot rolling blank is by hot rolling and as the hot rolled plate of required thickness of slab.Also, the hot rolling
Plate is decreased to product thickness of slab, and be carried out annealing by cold rolling after the processing of the descales such as pickling is carried out and thickness.Separately
Outside, as needed, cold forming processing is applied to the hot rolled plate, to be used in various uses.
More than, in the titanium plate base (the DC slabs for maintaining as-cast condition) 10 obtained by melting and casting, its thickness
Direction section as illustrated in FIG. 4 as, oxygen contamination layer 10P on the surface of the titanium plate base 10 be present, the oxygen contamination layer 10P with than
The oxygen concentration height of mother metal part (interior zone for not being carried out melt surface processing) is for example more than 0.1mass% degree highly concentrated
Degree is contained with high concentration more than 0.3mass%~0.5mass% degree higher than the oxygen concentration of mother metal part containing aerobic sometimes
Oxygen.Oxygen contamination layer 10P oxygen is mainly the oxygen of the atmosphere in the outside from slab, and absorption and inner side from oxygen-containing gas are expanded
Dissipate, therefore, oxygen concentration in oxygen contamination layer 10P, which has, to be gone from steel slab surface towards private side and diminish that (oxygen is dense for such gradient
Spend gradient).In addition, in this manual, oxygen contamination layer 10P refers to that oxygen concentration is higher 0.05mass% than the oxygen concentration of mother metal
Region above, it is, for example, than the average oxygen concentration C of mother metal from the oxygen gradient on slab thickness direction in Fig. 40It is high
More than 0.05mass% oxygen concentration Cq(=C0+ 0.05mass%) position PqPlay the region untill steel slab surface.
Herein, in foregoing electronic torch melting casting, cooling period in melting and casting and afterwards
In, the space in melting chamber 1 and casting-extraction chamber 5 is maintained vacuum originally, therefore should be unable to produce titanium plate base
Raw oxygen contamination.However, in fact, generate oxygen contamination layer 10P mostly.
Although it is conceivable that so producing oxygen contamination layer in steel slab surface there are several reasons, as already mentioned, make
For one of reason, alternatively it is conceivable to, after the titanium plate base of 1 batch is cast, when opening casting-extraction chamber, outside enters
Air in oxygen absorbed sometimes by steel slab surface.Especially, the titanium plate base when opening casting-extraction chamber atmosphere
Temperature also in high temperature in the case of, easily absorbed from the outside oxygen entered by titanium plate base, so as to which oxygen contamination becomes serious.
In addition, it is contemplated that for some reason, the vacuum in chamber in casting, especially from after mold extraction
High temperature slab around vacuum do not become fully high in the case of, steel slab surface is from the atmosphere around slab sometimes
Absorb oxygen.Particularly, in conventional common chamber, as shown in figure 1, oxygen during in order to prevent the melting of melting raw material is inhaled
Receive, for being usually provided in the side of melting chamber 1 to the vavuum pump 9 being exhausted in chamber, but it is contemplated that in this case, by
In exhaust position away from casting-extraction chamber 5 farther out, therefore, space in casting-extraction chamber 5, especially extract out in chamber 5B
The vacuum in space do not become abundant height sometimes, thus, extracting out in chamber 5B, oxygen containing residual gas is by high temperature sometimes
Titanium plate base 10 absorbs.
Also, being also contemplated that a reason is, can be adsorbed from the outside oxygen entered, oxygen-containing gas when opening chamber or
Person is attached to outer surface of the inwall of casting-extraction chamber 5, mold 6 etc., and is not carrying out what sufficiently exhaust vacuumized
In the case of by the Surface absorption of the slab of high temperature.No matter any reason, can expect, it is the oxygen of the atmosphere in chamber, oxygen-containing
The concentration of gas is unexpectedly uprised, and oxygen contamination layer is generated in steel slab surface.
Also, if the slab of oxygen contamination layer will be so generated on surface on the premise of surface cut processing is not implemented
(not removing oxygen contamination layer namely) is just supplied to melt surface processing, and the slab (hot rolling blank) after melt surface processing is entered
Row heating and hot rolling and hot rolled plate is made, and cold rolling further is carried out to it and if cold-reduced sheet or cold rolled annealed plate is made, then
Can as has been described produce cold rolling when, cold forming when crack problem.I.e., alternatively it is conceivable to, it is still remaining after melt surface processing
The higher state (state that oxygen contamination layer be present) of the oxygen concentration of the superficial layer of slab, if further using the slab as hot rolling
Heated with blank, then the oxygen concentration of superficial layer can be only uprised without reducing, and the hot rolled plate after hot rolling also maintains superficial layer
The higher state of oxygen concentration, during due to cold rolling, the cold forming of cold-reduced sheet or cold rolled annealed plate when superficial layer oxygen concentration
And the difference of the processability caused by the difference of the oxygen concentration of interior zone, is easily cracked.
Reference picture 5A~Fig. 5 D come specifically describe it is such from slab melting and casting play melt surface processing so as to
The varying motion of untill hot rolling acid-cleaning, oxygen contamination layer oxygen concentration distribution.
In fig. 5, by the slab thickness direction of titanium plate base (blank) 10 for maintaining DC as-cast conditions shown in Fig. 4
Oxygen concentration distribution a part, i.e. surface 10A nearby (Fig. 4 IV circles portion) oxygen concentration be distributed enlarged representation.In addition,
In Fig. 5 B, profit is shown in solid lines to titanium plate base implementation table be distributed with the oxygen concentration shown in Fig. 5 A, to maintain as-cast condition
The oxygen concentration distribution of slab after the melt process of face.In addition, the dotted line in Fig. 5 B represent Fig. 5 A it is shown in solid, maintain casting
Make the oxygen concentration distribution of the titanium plate base of state, i.e. the oxygen concentration of melt surface before processing is distributed.Also, in figure 5 c, show pair
Slab after oxygen concentration shown in solid with Fig. 5 B is distributed, melt surface processing carries out the oxygen of the hot rolled plate after hot rolling
Concentration distribution.In addition, show in figure 5d dense to the oxygen after the hot rolled plate implementation pickling with the oxygen concentration distribution shown in Fig. 5 C
Degree distribution.
As shown in Figure 5A, for the oxygen concentration for the slab (blank) for maintaining as-cast condition, its superficial layer in the slab
In gone from inner side (the mother metal side inside blank) towards steel slab surface and become big.Also, on the surface, the maximum of oxygen concentration
Cmax1 sometimes up to more than 0.5%.
The state representation after melt surface processing will be implemented in figure 5b to such titanium plate base for maintaining as-cast condition.
If implementing melt surface processing (Fig. 5 B) under the state (Fig. 5 A) when maintaining casting, oxygen concentration distribution can big amplitude variation
Change.That is, in melt surface processing, due to being melted by irradiation as the electron beam of high density energy and superficial layer and utilizing this
Energy carries out action of forced stirring to the liquation in molten bath, and therefore, oxygen flows because of stirring in molten bath, and the oxygen concentration in melting layer is real
Now equalize, as a result, the oxygen concentration gradient of melt surface before processing substantially disappears, remelted solidification layer after melting
(play depth d from surface1Untill region) in 20, oxygen concentration reaches generally uniform.Thus, relative in no oxygen contamination
The substantially uniform oxygen concentration C in portion region (mother metal)0(being usually 0.04mass%~0.2mass% or so), remelted solidification
It is in step-like state (the oxygen concentration C uprised that the oxygen concentration of layer 20, which turns into,m).That is, the slab after melt surface processing (use by hot rolling
Blank) in, superficial layer (remelted solidification layer 20) and than near the border between the superficial layer close to the inner portion region of side (it is strict come
Say, near the border between remelted solidification layer 20 and heat affected layer 22 in melt surface process layer), oxygen concentration is in step-like
Sharp change.
Also, in addition, as the superficial layer for making before processing in being handled in melt surface oxygen concentration equalize result,
In substantially whole region on thickness direction, the value C of the oxygen concentration of the remelted solidification layer 20 after melt surfacemThan before processing
The maximum C on surfacemax1 is small, but substantially than no oxygen contamination interior zone average oxygen concentration C0It is high.From Fig. 5 A, this
It is meant that handled by melt surface, average oxygen concentration C of the oxygen concentration than the interior zone of no oxygen contamination0High region (oxygen
Concentration CmRegion) greatly expand to the private side of plate.In addition, the oxygen concentration C by remelted solidification layer 20mRelative to inside
The average oxygen concentration C in region (mother metal part)0Increment be set to Δ Cm(=Cm- C0)。
Implement the slab after melt surface processing and be applied in hot rolling as hot rolling blank heating.Utilize Fig. 5 C solid line
Show that the oxygen concentration after hot rolling is distributed.Further, since overall thickness is reduced because of hot rolling, and therefore, the slab before hot rolling
In be d, d1、d2Part reduced respectively by hot rolling to d ', d1′、d2′.In addition, in hot rolled plate, in the slab before hot rolling
Utilize PqThe position of mark, i.e. with the oxygen concentration C than mother metal0High 0.05mass% oxygen concentration Cq(=C0+ 0.05mass%) phase
Corresponding position mark is Pq′。
Because the heating before hot rolling and hot rolling are generally carried out in an atmosphere, therefore, the surface of slab and hot rolled plate is oxidized,
In plate after hot rolling, shown in solid such as Fig. 5 C, the oxygen concentration at the position of the very thin layer on the surface of hot rolled plate sharp becomes
Greatly and reach C in surface locationmax2 (such as oxides more than degree of oxygen concentration 35%).In general, after hot rolling,
Carry out pickling, and by very thin, the thickness d on surface3Layer (generally, thickness d3For 0.03mm~0.1mm or so layer) dissolving
Remove, thus, generally the layer of the high oxygen concentration on caused surface is removed in heating-hot rolling.After such progress pickling
Oxygen concentration distribution represents in figure 5d.
Herein, in pickling processes after hot rolling, the very thin layer on surface is only removed, therefore, after pickling, such as Fig. 5 D institutes
Show, oxygen concentration distribution (step-like distribution in a thickness direction) inclines caused by because of the melt surface processing before hot rolling heating
To can be substantially constant remain.In the state of hot rolled plate i.e., after pickling, the surface of melt surface processing is being carried out
The region of remelted solidification layer 20 in melt process layer and more attached than the boundary position P1 between the region inside the region backup plate
Closely, oxygen concentration also can sharp change.Further, it is possible to expect, if such oxygen concentration is poor larger, in cold-workability side
Face, larger difference can be also produced in superficial layer and interior zone, as described above, in cold rolling, cold forming, can produce and split
Line, stripping.
In addition, in the present invention, as shown in Fig. 5 A~Fig. 5 D, the depth d of surface-treated layer 21 is set to compare oxygen contamination
Layer 10P depth, to play oxygen concentration from steel slab surface be Cq(=C0+ 0.05mass%) position PqUntill depth it is deep.
In addition, the depth d of the remelted solidification layer 20 in melt surface process layer 211Both it can be more than and might be less that oxygen
Pollution layer 10P depth, to play oxygen concentration from steel slab surface be Cq(=C0+ 0.05mass%) position PqUntill depth,
But the in fact, desirably depth d of remelted solidification layer 201It is C more than oxygen concentration is played from steel slab surfaceqPosition PqFor
Depth only.
In summary, alternatively it is conceivable to, melted due to the oxygen contamination layer on the surface of titanium plate base be present and implementing surface to the slab
The varying motion that the oxygen concentration of superficial layer when melting processing is distributed, as the heat after the processing of foregoing melt surface and hot rolling
Rolling plate can crack in the cold forming processing after cold rolling or cold-reduced sheet annealing.
However, the experimental study of many has been repeated in the present inventor etc., as a result find that a kind of melt surface processing is used
Titanium plate base, it is to form depth d on the surface of titanium plate base using melt surface processing1Remelted solidification layer and by with
The surface for rolling surface hot rolling to manufacture titanium when use, wherein, on the thickness direction of titanium plate base, will be from the table
Play d in face1Region untill/2 position is set to the 1st region, will be from the d1Play the d in/2 position1Position untill
Region is set to the 2nd region, the average oxygen concentration by the average oxygen concentration in the 1st region relative to the mother metal of the titanium plate base
Increment be set to C1, by the average oxygen concentration in the 2nd region relative to the average oxygen concentration of the mother metal of the titanium plate base
Increment is set to C2, by C1With C2Between poor C1- C2It is set to Cd, now, if C1For below 0.20mass%, C2For
Below 0.05mass% and CdMore than 0 and be below 0.15mass%, then melt surface processing after remelted solidification layer with than
Difference in oxygen concentration between the region of remelted solidification layer in the inner part also can be small to the journey not had undesirable effect to cold-workability
Degree, it can effectively prevent from cracking in cold rolling as the hot rolled plate after melt surface as described above processing and hot rolling,
In addition it is possible to effectively prevent from cracking when carrying out cold forming processing to cold rolled annealed plate.
Herein, also become big for generating the oxygen concentration gradient of the higher oxygen contamination layer of oxygen concentration and superficial layer and be unsatisfactory for
Slab (comparing with slab) in the case of the condition, using with it is in the slab of the present invention shown in Fig. 5 A, at melt surface
Thickness direction oxygen concentration distribution identical scale in stage before reason compares this rank of melt surface before processing with slab
Thickness direction oxygen concentration distribution in section represents in fig. 6.In addition, using with the slab of the present invention shown in Fig. 5 B, surface
Thickness direction oxygen concentration distribution identical scale in stage before melt process compares this carries out melt surface with slab
Thickness direction oxygen concentration distribution after processing represents in fig. 6b.
In addition, than the average oxygen concentration in the region (non-oxygen pollution layer) of oxygen contamination layer in the inner part substantially without by certainly
Influence caused by Surface absorption oxygen.Thus, for the oxygen amount in the region inside slab, slab and slab of the present invention are used comparing
Between difference is not present, can be considered as it is identical, therefore, in relevant Fig. 6 A, Fig. 6 B of slab is used compared with, and with plate of the present invention
Similarly, internal average oxygen concentration is represented as identical value C by the relevant Fig. 5 A of base, Fig. 5 B0。
Herein, also become for generating the oxygen concentration gradient of the higher oxygen contamination layer of oxygen concentration and superficial layer as described above
It is big and be unsatisfactory for the slab in the case of the condition and (compare and use slab；Fig. 6 A, Fig. 6 B) and meet the slab of the condition (originally
Invention slab；Fig. 5 A, Fig. 5 B), in Fig. 7 of same figure, with the thickness direction oxygen in the stage to melt surface before processing
Thickness direction oxygen concentration distribution in the stage of slab (hot rolling with blank) after concentration distribution and melt surface processing is carried out pair
The mode of ratio is shown.
As shown in Figure 6A, comparing with slab, along slab thickness direction to remelted solidification layer 20 from steel slab surface
Depth d11/2 (i.e. d1/ 2) average oxygen concentration of region (the 1st region) R1 untill position relative to mother metal averaged oxygen
Concentration C0Increased increment C1', with from d1Rise along slab thickness direction to the depth d equivalent to remelted solidification layer/2 position1
Position untill region (the 2nd region) R2 average oxygen concentration relative to mother metal average oxygen concentration C0Increased increment C2' it
Poor Cd' (=C1'-C2') more than 0.15mass%.Show that this compares with double dot dash line in the figure 7 to be melted with slab, surface
Melt the thickness direction oxygen concentration distribution of before processing.In addition, utilize Cmax1 ' shows superficial layer (oxygen contamination layer) in this case
Maximum oxygen concentration (oxygen concentration of surface location).
In addition, using slab for comparing, shown in the figure 7 using dotted line and melt surface is carried out with the depth d away from surface
(depth of remelted solidification layer is d after processing1) slab thickness direction on oxygen concentration distribution.As having described, in depth
Spend d1Remelted solidification layer in, oxygen concentration on thickness direction realizes equalization, with Cm' oxygen concentration reach generally uniform.
That is, it is in step-like increased point that boundary position of the oxygen concentration between remelted solidification layer and mother metal on thickness direction, which turns into,
Cloth.Also, in depth d1Position (boundary position between remelted solidification layer 20 and mother metal) near, oxygen concentration is in thickness
From C on direction0It is changed to drastically and significantly Cm′。
On the other hand, in slab of the present invention, the 1st region R1 average oxygen concentration relative to mother metal average oxygen concentration C0
Increment C1With the 2nd region R2 average oxygen concentration relative to mother metal average oxygen concentration C0Increment C2Between poor CdFor
Below 0.15mass%.Profit illustrate with dashed lines in the slab of the present invention, melt surface before processing thickness direction in the figure 7
Oxygen concentration is distributed.In addition, utilize Cmax1 shows maximum oxygen concentration (the surface position of superficial layer (oxygen contamination layer) in this case
The oxygen concentration put).
Herein, be unsatisfactory for the 1st region R1 average oxygen concentration relative to mother metal oxygen concentration C0Increased increment and the 2nd
Region R2 average oxygen concentration relative to mother metal oxygen concentration C0Poor C between increased incrementdFor below 0.15mass% bar
The situation of the comparison slab of part (that is, is comparing with plate, Cd' ＞ 0.15mass%) compare, meet above-mentioned 1st region R1's
Average oxygen concentration relative to mother metal average oxygen concentration C0Increased increment and the 2nd region R2 average oxygen concentration relative to mother
Material average oxygen concentration C0Poor C between increased incrementdFor below 0.15mass% condition slab of the present invention situation (i.e.
Cd≤ 0.15mass%) under thickness direction on oxygen concentration gradient (inclination) it is smaller.If in addition, as it was previously stated, in slab
The average oxygen concentration of the non-oxygen Polluted area in portion is identical C0, then the oxygen concentration gradient on thickness direction (inclination) is smaller, table
The oxygen concentration (maximum oxygen concentration) of face position is just smaller.Thus, (compare by the double dot dash line to Fig. 7 and use slab；Melt surface
Before processing) and dotted line (slab of the present invention；Melt surface before processing) be compared it will be apparent that, the surface location of slab of the present invention
Oxygen concentration (maximum oxygen concentration) C at placemax1 less than the oxygen concentration (maximum oxygen concentration) compared with the surface location in slab
Cmax1′.Also, in slab of the present invention, depth d is being played from surface1Position untill part contained by total oxygen amount
Also less than comparing depth d is played with slab from surface1Position untill part contained by total oxygen amount.
Also, the slab of the present invention for being distributed with the oxygen concentration shown in above-mentioned chain-dotted line (meets the plate of the condition
Base), Fig. 7 solid line is shown with depth the d (=d away from surface1+d2) carry out melt surface processing after slab thickness direction on
Oxygen concentration is distributed.In the case of the slab of the present invention, as the oxygen concentration distribution on the thickness direction after melt surface processing
Tendency, also compared with the oxygen concentration distribution on the thickness direction after the processing of the melt surface of slab similarly, in depth d1
Remelted solidification layer 20 in, oxygen concentration on thickness direction realizes equalization, turns into the oxygen concentration C of constantm, relative to
Mother metal oxygen concentration C0Increased increment Delta CmAlso constant is reached in a thickness direction.That is, the oxygen concentration distribution on thickness direction
As step-like distribution.But play depth d near surface in slab of the present invention1Position nearby untill part
In constant oxygen concentration CmLess than melt surface processing after comparison with slab (Fig. 7 dotted line) near surface
Play depth d1Position nearby untill part in constant oxygen concentration Cm′.The reason is that as it was previously stated, at this
In invention slab, depth d is being played from surface1Position untill part contained by total oxygen amount less than comparing with slab
Playing depth d from surface1Position untill part contained by total oxygen amount.Also, understand, in depth d1Position
Near (remelted solidification layer and than the boundary position between the mother metal region of the remelted solidification layer in the inner part), oxygen concentration exists
In step-like from C on thickness direction0Change turns to Cm, but the degree of the change, i.e. oxygen concentration increment Delta Cm(=Cm- C0) be less than than
Compared with slab from C0To CmDegree (the oxygen concentration increment Delta C of ' changem'=Cm'-C0).That is, in slab of the present invention, then
Melting and solidification layer and than the oxygen amount on the thickness direction near the boundary position between the region of remelted solidification layer in the inner part
Drastically change relaxed.
As described above, by making the oxygen concentration gradient in the thickness of slab direction in superficial layer smaller, can relax based on surface
The remelted solidification layer of melt process and than the oxygen concentration near the border between the region of remelted solidification layer in the inner part
Change.Also, the tendency is also being maintained after being heated before implementing hot rolling, after further implementation hot rolling, remelted will can coagulated
Gu the increased increment of the oxygen concentration relative to mother metal of the oxygen concentration of layer suppresses smaller.That is, in the state of hot rolled plate, also can
Enough relax remelted solidification layer and than the border vicinity between the region of remelted solidification layer in the inner part oxygen amount drastically
Change.As a result, due to surface layer part (remelted solidification layer) and than cold between the region of the surface layer part in the inner part
The difference of processability and the possibility that is cracked in cold rolling reduces, in addition, after cold rolled annealed, when carrying out cold forming processing
The possibility cracked reduces.
More than, in the present invention, the degree as the oxygen concentration gradient on the thickness direction in the superficial layer for representing slab
The index of (inclination), using relevant with the 1st region R1 relative to mother metal average oxygen concentration C0Increased increment C1With with the 2nd area
Domain R2 is relevant relative to mother metal average oxygen concentration C0Increased increment C2Between poor Cd, by the poor Cd(=C1- C2) be limited in
Below 0.15mass%.
Herein, if the superficial layer in slab has above-mentioned difference in oxygen concentration CdIt is larger dense more than as 0.15mass%
Spend gradient, then melt surface processing after remelted solidification layer and than the border between the region of remelted solidification layer in the inner part
The change of neighbouring oxygen concentration become it is big (for example, in the state of after melt surface processing, the oxygen concentration C of remelted solidification layerm's
Relative to mother metal average oxygen concentration C0Increased increment Delta CmMore than 0.1%).As a result, it is difficult to prevent to foregoing
Hot rolled plate carry out cold rolling when crackle, to cold rolled annealed plate carry out cold forming when crackle, peel off.
In addition, relevant with the 1st region R1 relative to mother metal oxygen concentration C0Increased increment C1More than 0.2mass%'s
In the case of or it is relevant with the 2nd region R2 relative to mother metal oxygen concentration C0Increased increment C2In the case of 0.05%, table
Remelted solidification layer after the melt process of face and the oxygen than the border vicinity between the region of remelted solidification layer in the inner part
The change of concentration become it is big (for example, in the state of after melt surface processing, the oxygen concentration C of remelted solidification layermRatio mother metal
Oxygen concentration C0Increased increment Delta CmMore than 0.1%).As a result, it is difficult to prevent to carry out cold rolling to foregoing hot rolled plate
When crackle, to cold rolled annealed plate carry out cold forming when crackle peel off.
In addition, if it is possible to by the poor C of the increment of the oxygen concentration of above-mentioned melt surface before processingdSuppress in 0.10mass%
Hereinafter, then the effect of the present invention can further be improved.
In addition, depth (the original away from before processing as the remelted solidification layer in the melt surface processing applied to slab
The depth of plate surface position) d1Specific numerical value, preferably in the range of 3.0mm~10.0mm.In remelted solidification layer
When depth is less than 3.0mm, smoothing, the surface of the superficial layer for carrying out melt surface processing and realizing can not be fully utilized
The removal effect of defect in layer.On the other hand, even if the depth of remelted solidification layer is more than 10.0mm, the effect of melt surface processing
Fruit also will not become big again, only can unnecessarily cause increase, the reduction of productivity ratio of energy cost.
In addition, the depth in the 1st region, the 2nd region as the benchmark of the thickness direction concentration gradient of the superficial layer of slab
According to the depth d for the surface melt process implemented afterwards1And it is set as depth d11/2, thus, each region it is specific
Depth (d1/ 2) it is 0.15mm~5mm or so.
In addition, as it was previously stated, generally, if in advance limitation slab surface layer thickness direction on oxygen concentration gradient,
As having described, the maximum oxygen concentration of surface location also diminishes, and therefore, does not implement cutting even in melt surface before processing and adds
Work, it can also obtain action effect as described above.But according to circumstances, also it is allowed in and removes surface using machining
Very thin layer after implement melt surface processing.But cutting depth in this case is the depth smaller than 3.0mm.
Herein, even if the high oxygen concentration portion of cutting removal skin section, the concentration gradient on the depth direction of oxygen will not also become
Change, but because cutting eliminates high oxygen concentration portion, therefore, total oxygen amount of remelted solidification layer tails off, above-mentioned 1st region R1's
The difference of oxygen concentration and the 2nd region R2 oxygen concentration diminishes, in regional relative to mother metal oxygen concentration C0It is increased
Increment C1、C2Poor CdIn the case where being not below 0.15mass% in the state of maintaining before the cutting of as-cast condition, also can
Above-mentioned poor C is enough obtained using machiningdFor below 0.15mass% slab.But if the cutting depth on top layer surpasses
3.0mm is crossed, then the burden of machining is become big and productivity ratio may be hindered, therefore, in the case where being cut, makes top layer
Cutting depth be below 3.0mm.
When manufacturing the melt surface titanium plate base of (melting and casting) present invention, for limiting the table of slab as described above
The specific method of the oxygen concentration of surface layer is simultaneously not particularly limited, such as can apply such various sides shown in following A~C
Method.In addition, countermeasure A be primarily used for preventing melting and casting terminate after atmosphere opening when oxygen contamination method.It is in addition, right
The method of oxygen contamination when plan B and countermeasure C is primarily used for preventing melting and casting.In fact, it is preferable that combination application this
More than two countermeasures in a little countermeasures.
Countermeasure A：In the case where slab is also in high temperature, especially steel slab surface temperature is that the phase transition temperature of titanium is 900
In the case of more than DEG C degree, easily produce because in atmosphere opening when air into caused by chamber, oxygen absorbed by slab
Situation.Therefore, after the slab of melting and casting predetermined length, less than 900 DEG C or so are reached in the surface temperature of slab
Just carry out atmosphere opening.Now, slab can have both been placed in chamber no matter, or raising productivity ratio and accelerated
Cooling.It it is 900 DEG C in surface temperature for example, it is also possible to be to be provided for cooling down the cooling-part of slab in extraction chamber in advance
Atmosphere opening is carried out in the state of below left and right., in advance will be cold after internal water cooling for example, can apply as the cooling-part
But plate is with close to the state of slab setting etc..Alternatively, it is also possible to be, before atmosphere opening, the cryogenic gases such as inert gas are utilized
To replace the atmosphere in chamber, surface temperature is turned into advance below 900 DEG C of degree, reach less than 900 DEG C in steel slab surface
Atmosphere opening is carried out at the time of low temperature.
Countermeasure B：As has been explained above, generally, for the purpose for being mainly used in remaining melting chamber 1 vacuum, use
The vavuum pump 9 (reference picture 1) being exhausted in chamber away from the casting-position of extraction chamber 5 farther out mostly to arrange
The mode of gas is attached.In this case, as shown in for example using Fig. 1 chain-dotted line, relative to the true of melting chamber
The vavuum pump 9 of idle discharge gas independently, sets the 2nd vavuum pump 91, the blast pipe 91a of the 2nd vavuum pump 91 is connected into casting
The side of chamber 5, the extraction chamber 5B sides especially opened to outer gas are made-extract out, casting during so as to improve melting and casting is taken out
The vacuum gone out in chamber 5.
Countermeasure C：In melting and casting, in order to reduce the partial pressure of the oxygen in atmosphere, oxygen-containing gas, such as such as Fig. 1 point
Shown in line like that, in advance the inner surface etc. for extracting chamber 5A out set the higher target of the absorbability of oxygen or oxygen-containing gas,
Such as the component 92 formed by titanium, zirconium etc..The vacuum in chamber when in addition, in order to improve casting smelting, also may be used
To use the bigger vavuum pump of exhaust capacity.Alternatively, it is also possible to be applied in combination for by the gas in chamber during casting smelting
The part of close property raising etc..
Herein, the industrial pure titanium for forming the titanium plate base of the present invention includes the class of 1 class~4 and phase therewith by JIS standards
Industrial pure titanium as defined in Grade1~4 of corresponding ASTM standard, 37025,37025, the 37025 of DIN standards.
I.e., it is possible to say that the industrial pure titanium in the present invention as object includes C in terms of quality %：Less than 0.1%, H：Less than 0.015%,
O：Less than 0.4%, N：Less than 0.07%, Fe：Less than 0.5%, remaining is Ti.And then a little platinum family member is added among them
Element, be referred to as improve (improvement) pure titanium highly corrosion resistant alloy (ASTM Grade 7,11,16,26,13,30,33 or and it
Corresponding to JIS classes) be also regarded as being included within industrial pure titanium in the present invention.
In addition, the size of the surface treatment titanium plate base 10 of the present invention does not have then if size that can directly for hot rolling
It is particularly limited to, but as hot rolling application coil rolling (coil rolling) and is manufacturing thickness of slab 3mm~8mm or so hot rolling
In the case of coiled thin middle plate, as titanium plate base, as long as thickness 150mm~280mm or so, length 3m~10m or so, width is made
Spend 600mm~1500mm or so.
In the titanium material for hot rolling of the actual use present invention, implement hot rolling and the hot rolled plate of expectation thickness of slab is made.Hot rolling
Mode be not particularly limited, but when laminating hot rolling slab products, commonly used coil rolling.In addition, in this case
The final thickness of slab of hot rolling is not particularly limited, usually 3mm~8mm or so.Hot-rolled condition is not particularly limited, with common titanium heat
Roll similarly in 720 DEG C~920 DEG C carry out 60 minutes~420 minutes or so heat, within the range at a temperature of start hot rolling,
According to the ability of milling train more than room temperature at a temperature of terminate hot rolling.
Below, embodiments of the invention are illustrated together with comparative example.
Embodiment
Test example 1
Using the pure titanium of JIS1 classes as melting raw material, DC castings are carried out by electronic torch melting using equipment as shown in Figure 1
Make, obtained section be about 1300mm it is wide × about 400mm thickness × about 7500mm length titanium plate base.Casting speed is
2ton/h。
In melting and casting, in order to suppress the oxygen concentration of the superficial layer of the slab (No.1~No.6 of table 1) of a part,
Apply countermeasure more than any one in the countermeasure A~countermeasure C.It is unreal for the slab (No.7 of table 1) of a part
It is applied to the countermeasure for the oxygen concentration for suppressing superficial layer.
In addition, for the DC slabs to be manufactured with No.7 identicals condition, in the advance of ensuing melt surface processing
Surface cut (cutting depth is 0.5mm~2.5mm) is gone, No.8~No.12 of table 2 slab is made.
Afterwards, while continuously moving slab, while being carried out using electron beam irradiation to wider two face of slab
Melt surface processing, has been made titanium material for hot rolling.In melt surface processing, use is so that rectangular electron beam size adjusting is
2.5cm electron beam, make other electron beam irradiation conditions (slab translational speed when the power output of electron beam, irradiation, every
1cm heat input etc.) change, make fusion penetration (depth of remelted solidification layer) d away from surface location of slab1Change.
In above process, for melt surface before processing each titanium plate base wider face, using for section
EPMA analyses (X-ray microanalysis instrument) are quantitatively investigated the oxygen concentration of the superficial layer in the face and its distribution.That is, adjust
The oxygen concentration C on surface is looked intomax, mother metal part average oxygen concentration C0, also, the mesh that the melt surface carried out afterwards is handled
The depth for marking the remelted solidification layer of (predetermined) is set to d1, to playing depth d from the surface1Region (the 1st area untill/2
Domain R1) oxygen concentration the average oxygen concentration C relative to mother metal part0Increment C1With from depth d1/ 2 play d1Untill area
The average oxygen concentration C relative to mother metal part of the oxygen concentration in domain (the 2nd region R2)0Increment C2Investigated.
In addition, the example (No.8~No.12) for having carried out surface cut before melt surface processing is carried out, investigation
Each oxygen concentration after cutting.
By the oxygen concentration of the superficial layer relevant with each slab No.1~No.12 of these melt surface before processings and its distribution
Investigation result represent in Tables 1 and 2.
On the other hand, for each titanium plate base after melt surface processing (for titanium material for hot rolling；Carrying out surface cut
In the case of be the cutting after blank) wider face, investigated the oxygen concentration C on surfacemax, mother metal part averaged oxygen it is dense
Spend C0, to playing d from surface1Position untill (i.e. remelted solidification layer play bottom from surface untill) part oxygen it is dense
The average oxygen concentration C relative to mother metal part of degree0Increment Delta CmInvestigated.It the results are shown in table 3.
Also, the titanium material for hot rolling after the completion of by obtained melt surface processing as described above is inserted into 800 DEG C
Stove in after, heat within about 240 minutes, manufacture the thick hot rolled strip volumes of 5mm with continuously hot rolling band and strip rolling mill, through bag
Continuous acid-washing production line containing nitric acid-hydrofluoric acid, about 40 μm are pruned per one side dissolving.
Afterwards, hot rolled strip volume is cold-rolled to 0.75mm, surface observation is carried out centered on end and investigates the production of crackle
Raw situation, using the situation (judging A) not cracked completely although, crack seldom, be practically without the feelings of problem
Condition (judge B~judgement C), the situation of severe crack (judging D) this 4 ranks have rated the degree of the crackle.
Then, after being annealed with the condition of 650 DEG C × 5 hours in argon gas atmosphere, cold formability has been investigated.It is cold
Formability test is carried out (according to JIS Z 2247) by AEG-process.
These evaluation results are shown in Table 3 below in the lump.
Table 1
Table 2
Table 3
As shown in Table 1 to Table 3, for the titanium plate base of melt surface before processing, confirm, each example of the present invention (No.1~
No.6, No.8~No.12) and comparative example (No.7) in, be C1＞ C2, there is oxygen amount to be gone from surface towards inside and reduce
Oxygen concentration gradient.
In addition, in each example of the present invention, Cd(=C1- C2) it is below 0.15mass%.In addition, at for melt surface
Titanium plate base (titanium material for hot rolling) after reason, in each example of the present invention, d is played from surface1Position untill (i.e. remelted solidification
Layer play bottom from surface untill) part oxygen concentration constant, the oxygen concentration relative to mother metal part oxygen concentration
C0Increment Delta CmIt is below 0.1mass%.
Also, in these examples of the present invention, confirm, do not cracked in the cold rolling of the roll bending after hot rolling and pickling
(judging A), although or generating crackle few (judging B~judgement C), being practically without hindering.In addition, for cold rolling-move back
Cold formability after fire has also obtained more than 11.5mm Erichsen number, and it is good to confirm it.Especially, in the 2nd technical scheme
Middle restriction, Cd(=C1- C2) value is in below 0.1mass% No.3,6,11,12, crackle when not producing cold rolling (judges
A), Erichsen number is also shown for more than 12mm high level.
On the other hand, in the No.7 as comparative example, Cd(=C1- C2) exceed 0.15mass%.In addition, for table
Titanium plate base (titanium material for hot rolling) after the melt process of face, in each comparative example, d is played from surface1Position untill (melt again
Melt solidification layer play bottom from surface untill) the oxygen concentration of part be constant in the same manner as each example of the present invention, but should
Oxygen concentration relative to mother metal part average oxygen concentration C0Increment Delta Cm0.1mass% is exceeded.
Also, in the comparative example, confirm, although not cracked in cold rolling, after cold rolling-annealing it is cold into
Shape is poor (Erichsen number is below 11mm).
Test example 2
Using the pure titanium of ASTM grades 2 as melting raw material, carried out using equipment as shown in Figure 1 by electronic torch melting
DC cast, obtained section be about 1100mm it is wide × about 220mm thickness × about 7000mm grow titanium plate base.Average casting speed
Spend for 1.9ton/h.
It is dense in order to suppress the oxygen of the superficial layer of the slab (No.13~No.18 of table 4) of a part in melting and casting
Degree, applies countermeasure more than any one in the countermeasure A~countermeasure C.For a part slab (No.19 of table 4),
The countermeasure of the oxygen concentration for suppressing superficial layer is not carried out.
In addition, for the DC slabs to be manufactured with No.19 identicals condition, in the advance of ensuing melt surface processing
Surface cut (cutting depth is 0.5mm~2.5mm) is gone, No.20~No.24 of table 5 slab is made.
Afterwards, while continuously moving slab, while being carried out using electron beam irradiation to wider two face of slab
Melt surface processing, has been made titanium material for hot rolling.In melt surface processing, use is so that rectangular electron beam size adjusting is
2.5cm electron beam, make other electron beam irradiation conditions (slab translational speed when the power output of electron beam, irradiation, every
1cm heat input etc.) change, make fusion penetration (depth of remelted solidification layer) d away from surface location of slab1Change.
In above process, for melt surface before processing each titanium plate base wider face, in the same manner as test example 1,
The oxygen concentration of the superficial layer in the face and its distribution are quantitatively entered using the EPMA analyses (X-ray microanalysis instrument) for section
Investigation is gone.
In addition, the example (No.21~No.24) for having carried out surface cut before melt surface processing is carried out, is adjusted
Each oxygen concentration looked into after cutting.
By the oxygen concentration and its point of the superficial layer relevant with each slab No.13~No.24 of these melt surface before processings
The investigation result of cloth is represented in table 4 and table 5.
On the other hand, for each titanium plate base after melt surface processing (for titanium material for hot rolling；Carrying out surface cut
In the case of be the cutting after blank) wider face, investigated the oxygen concentration C on surfacemax, mother metal part averaged oxygen it is dense
Spend C0, to playing d from surface1Position untill (i.e. remelted solidification layer play bottom from surface untill) part oxygen it is dense
Average oxygen concentration C spend, relative to mother metal part0Increment Delta CmInvestigated.It the results are shown in table 6.
Also, the titanium material for hot rolling after the completion of by obtained melt surface processing as described above is inserted into 800 DEG C
Stove in after, heat within about 240 minutes, manufacture the thick hot rolled strip volumes of 5mm with continuously hot rolling band and strip rolling mill, through bag
Continuous acid-washing production line containing nitric acid-hydrofluoric acid, about 40 μm are pruned per one side dissolving.
Afterwards, hot rolled strip volume is cold-rolled to 1.2mm, surface observation is carried out centered on end and investigates the generation of crackle
Situation, the evaluation for crackle, in the same manner as test example 1, judged using 4 ranks (judging A~judgement D).Should
Evaluation result is shown in Table 6 below.
Table 4
Table 5
Table 6
As shown in 4~table of table 6, for the titanium plate base of melt surface before processing, confirm, each example of the present invention (No.14,
15th, 17,18,21~24) and in comparative example (No.13,16,19,20), it is respectively provided with oxygen amount and goes and reduce from surface towards inside
Oxygen concentration gradient (C1＞ C2)。
In addition, in each example of the present invention, Cd(=C1- C2) it is below 0.15mass%.In addition, at for melt surface
Titanium plate base (titanium material for hot rolling) after reason, in each example of the present invention, d is played from surface1Position untill (i.e. remelted solidification
Layer play bottom from surface untill) part oxygen concentration constant, the oxygen concentration relative to mother metal part oxygen concentration
C0Increment Delta CmIt is below 0.1mass%.
Also, in these examples of the present invention, confirm, do not cracked in the cold rolling of the roll bending after hot rolling and pickling
(judging A), although or generating crackle few (judging B~judgement C), being practically without hindering.Especially, in the 2nd technology
Limited in scheme, Cd(=C1- C2) value be below 0.10mass% No.18,22,23,24 in, splitting when not producing cold rolling
Line (judges A), has high cold-rolling property.
On the other hand, in as the No.19 of comparative example, 20, Cd(=C1- C2) exceed 0.15mass%.In addition,
No.13 as comparative example, in 19, C1Exceed 0.2mass%, similarly, in as the No.13 of comparative example, 16,19, C2
0.05mass% is exceeded.
In these each comparative examples, for the titanium plate base (titanium material for hot rolling) after melt surface processing, played from surface
d1Position untill (i.e. remelted solidification layer play bottom from surface untill) part oxygen concentration and each example of the present invention it is same
It is constant, but the oxygen concentration is relative to the average oxygen concentration C of mother metal part sample0Increment Delta CmExceed
0.1mass%.
Also, in these comparative examples, confirm, generate significant crackle (judging D) in cold rolling, cold-workability compared with
Difference.
More than, it is illustrated for the preferred embodiment of the present invention, embodiment, but embodiment and embodiment are returned
Root knot bottom is only the example in spirit of the scope of the present invention, as long as without departing from the gist of the present invention, it is possible to right
Composition is added, omitted, replacing and other changes.I.e. the present invention is not limited to above-mentioned explanation, simply by enclosing
The scope of claims be defined, and suitable change can be carried out within the range.
Description of reference numerals
10th, titanium plate base；12nd, electron beam irradiation rifle；16th, melt surface process layer；d1, melt surface process layer depth；
R1, the 1st region；R1, the 2nd region.
Claims (7)
1. titanium plate base is used in a kind of melt surface processing, it is to form depth d on the surface of titanium plate base using melt surface processing1
Remelted solidification layer and by using the surface as the hot rolling of rolling surface to manufacture titanium when use, wherein,
The titanium plate base be by made from the DC slab casting methods under vacuum or inert gas atmosphere, maintain as-cast condition
Titanium plate base,
On the thickness direction of the titanium plate base, d will be played from the surface1Region untill/2 position is set to the 1st region,
Will be from the d1Play the d in/2 position1Position untill region be set to the 2nd region, by being averaged in the 1st region
Oxygen concentration is set to C relative to the increment of the average oxygen concentration of the mother metal of the titanium plate base1, by the averaged oxygen in the 2nd region
Concentration is set to C relative to the increment of the average oxygen concentration of the mother metal of the titanium plate base2, by C1With C2Between poor C1- C2It is set to
Cd, now,
C1For below 0.20mass%, C2For below 0.05mass%, and CdMore than 0 and it is below 0.15mass%.
2. titanium plate base is used in melt surface processing according to claim 1, wherein,
The CdFor below 0.10mass%.
3. titanium plate base is used in melt surface processing according to claim 1 or 2, wherein,
The d1In the range of 3.0mm~10.0mm.
4. titanium plate base is used in melt surface processing according to any one of claim 1 to 3, wherein,
The surface is eliminated with below 3.0mm thickness cutting.
5. a kind of titanium material for hot rolling, wherein,
The titanium material for hot rolling is that the table in the titanium plate base any one of Claims 1-4 is being handled using melt surface
Face forms depth d1Remelted solidification layer and by using the surface as the hot rolling of rolling surface to manufacture titanium when use.
6. titanium material for hot rolling according to claim 5, wherein,
Oxygen concentration on thickness direction is distributed in boundary position between the remelted solidification layer and mother metal from mother metal towards table
Face is in step-like increase.
7. titanium material for hot rolling according to claim 6, wherein,
The average oxygen concentration of the remelted solidification layer relative to the average oxygen concentration of the mother metal increment for 0.1mass% with
Under.
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| CN111819012A (en) * | 2018-06-27 | 2020-10-23 | 东邦钛株式会社 | Method for producing titanium material for hot rolling and method for producing hot rolled material |
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| CN108546831A (en) * | 2018-05-25 | 2018-09-18 | 南京尚吉增材制造研究院有限公司 | Titanium and titanium alloy short route preparation facilities and method |
| CN108546831B (en) * | 2018-05-25 | 2020-07-24 | 南京尚吉增材制造研究院有限公司 | Short-process preparation device and method for titanium and titanium alloy |
| CN111676380A (en) * | 2018-05-25 | 2020-09-18 | 南京尚吉增材制造研究院有限公司 | Short-process preparation device for titanium and titanium alloy |
| CN111676380B (en) * | 2018-05-25 | 2021-06-25 | 南京尚吉增材制造研究院有限公司 | Short-process preparation device for titanium and titanium alloy |
| CN111819012A (en) * | 2018-06-27 | 2020-10-23 | 东邦钛株式会社 | Method for producing titanium material for hot rolling and method for producing hot rolled material |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2017018454A1 (en) | 2017-02-02 |
| JPWO2017018454A1 (en) | 2017-07-27 |
| CN107614153B (en) | 2019-10-15 |
| JP6324549B2 (en) | 2018-05-16 |
| JP2018083232A (en) | 2018-05-31 |
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Address after: Tokyo, Japan, Japan Applicant after: Nippon Iron & Steel Corporation Applicant after: Toho Titanium Co., Ltd. Address before: Tokyo, Japan, Japan Applicant before: Nippon Steel Corporation Applicant before: Toho Titanium Co., Ltd. |
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