CN107614153B - 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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- CN107614153B CN107614153B CN201680031125.8A CN201680031125A CN107614153B CN 107614153 B CN107614153 B CN 107614153B CN 201680031125 A CN201680031125 A CN 201680031125A CN 107614153 B CN107614153 B CN 107614153B
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- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 title claims abstract description 172
- 239000010936 titanium Substances 0.000 title claims abstract description 171
- 229910052719 titanium Inorganic materials 0.000 title claims abstract description 170
- 238000012545 processing Methods 0.000 title claims abstract description 120
- 238000005098 hot rolling Methods 0.000 title claims abstract description 113
- 239000000463 material Substances 0.000 title claims abstract description 88
- 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
- 238000005266 casting Methods 0.000 claims abstract description 74
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- 238000005520 cutting process Methods 0.000 claims description 36
- 229910052793 cadmium Inorganic materials 0.000 claims description 3
- 238000005097 cold rolling Methods 0.000 abstract description 29
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- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- 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
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (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 melt surface processing titanium plate base, be using melt surface handle as the DC slab casting method under vacuum or inert gas atmosphere made from, maintain as-cast condition titanium plate base surface formation depth d1Remelted solidification layer and by being used when manufacturing titanium using the surface as the hot rolling of rolling surface, wherein on the thickness direction of the titanium plate base, d (is played from the surface in the 1st region1Region until/2 position) in average oxygen concentration relative to the titanium plate base base material average oxygen concentration increment C1For 0.20mass% hereinafter, the 2nd region is (from the d1Play the d in/2 position1Position until region) in average oxygen concentration relative to the titanium plate base base material average oxygen concentration increment C2For 0.05mass% hereinafter, Cd(=C1- C2) be greater than 0 and be 0.15mass% or less.It is excellent in terms of processability in the melt surface processing cold rolling or cold forming of titanium plate base after hot rolling.
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 of hot rolling made of melt process.
Background technique
In general, it as industrial pure titanium, is usually 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), electron-beam smelting (EBR) or plasma arc melting
Smelting process carry out melting and be formed as large-scale slab (ingot casting).Herein, as casting blank shape, in the feelings of vacuum arc melting
Under condition, it is defined in columned slab (circle ingot casting (billet)), it is on the other hand, molten in electron-beam smelting, plasma arc
In the case where refining, the slab of rectangular in form, i.e. slab can be cast.
In turn, when manufacturing titanium sheet metal as blank using such large-scale slab, in general, as needed to large size
After slab 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, size hot rolling blank.The hot procedure based on these breaking down or forging is known as cogging process herein
(breakdown step).Moreover, in order to further remove the oxidation formed on the superficial layer of the blank of the hot rolling after cogging
Nitride layer, oxygen coalescence layer, usually superficial layer is pruned to a few mm degree or more using machining, close to after 10mm, be supplied to heat
It rolls.
However, in general method previous in this way, for being processed into the shape for being suitable for hot rolling, ruler from large-scale slab
The cogging process of very little breaking down or forging needs plenty of time and cost, this improves the productivity of titanium sheet metal manufacture, cost drops
It is low to become big bottleneck.
Recently, substitution large-scale casting ingot casting, the slab shape slab relatively thin as manufacture have and can directly be supplied to
Shape, the method for the slab of size of hot rolling and the technology for gradually establishing DC (direct pouring) slab casting method.The casting of DC slab
The method of making is following method: the titanium melt melted in siege using electron-beam smelting or plasma arc melting is continuously infused
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 slab of predetermined length.
If the cogging process needed can be omitted, as a result, it is possible to improve titanium using the DC slab casting method in the past
The productivity of thin plate manufacture simultaneously reduces manufacturing cost.
However, for obtained by the DC slab casting method slab (hereinafter, also referred to " DC slab ".), in general, slab
The bumps on surface layer are serious and defect is more.Plate (hot rolled plate) if such slab is directly supplied to hot rolling, after hot rolling
Surface texture be deteriorated.Therefore, actual conditions are, before hot rolling, it has to implement the cutting of several mm to 20mm or so to surface
Processing.Thus, the yield rate of material reduces, and additionally needs effort, the cost of machining, therefore improved requirement is still strong
It is strong.
Moreover, even if there is also after hot rolling in the case where being supplied to hot rolling after implementing surface cutting processing to DC slab
The surface texture of hot rolled plate may not become good problem.That is, there are the following problems: largely generating size in hot rolling plate surface and reach
The flaw of the cover shape (Japanese: by さ り shape) of length to several mm to 10mm or so.The surface blemish of such hot rolled plate from
The coarse 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 when casting；" maintaining state when casting ") coarse crystal grain including cast sturcture, i.e.,
Make to implement its surface machining, there is also coarse tissues on the superficial layer after cutting, due to surface coarse in this way
Cast sturcture causes to generate surface blemish on hot rolled plate.
However, generating the hot rolling after hot rolling in order to prevent for without titanium material for hot rolling obtained from cogging process
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: becoming rolling surface to the surface of titanium plate base, especially 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, so that its superficial layer is melted to the depth of 1mm or more, exists side by side and solidified again even if its quenching.
Using such method, the superficial layer of titanium plate base is melted, thus being smoothed of surface, and the stomata in superficial layer
The defects of disappear, further, since by from the heat extraction of base material side make melting layer be quenched and solidify while, the hot shadow of downside
It rings layer (HAZ layer) to be quenched, melting layer and HAZ layers are as small phase-change organization.Moreover, the superficial layer of so microminiaturization exists
It is recrystallized when heating of plate blank before hot rolling later, it is (isometric to become small and with irregular orientation granular tissue
Grain structure).Therefore, the recess caused by capable of preventing by coarse tissue can also eliminate the hot rolled plate after hot rolling
Surface blemish.
In addition, in the present specification, it will be by assigning high-energy to the surface of titanium plate base as described above and only making surface
Layer melting, existing side by side is referred to as at melt surface even if its method of quenching solidification to be modified processing to the superficial layer of titanium plate base
Reason.In addition, in the present specification, superficial layer melting being made using melt surface processing and then the melting layer being concretionary again
Layer is referred to as remelted solidification layer.Also, the material (slab) of melt surface treated hot rolling in the present specification, will be implemented
Referred to as hot rolling blank.
Existing technical literature
Patent document
Patent document 1: Japanese Unexamined Patent Publication 2007-332420 bulletin
Summary of the invention
Problems to be solved by the invention
In addition, for carrying out hot-finished material obtained from hot rolling after implementing melt surface processing to DC slab, it is general next
It says, cold rolling is implemented to it later and the hot-finished material is made to become thickness corresponding with product-use.According to circumstances, sometimes also
It can implement the cold formings such as bending, drawing, stretching processing.After even if use implements melt surface processing as original material using DC slab
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 inventors of the present invention, as a result understood fully its be by as follows the phenomenon that cause
's.
That is, first confirm that, the face crack in cold rolling as described above, cold forming processing is enriched in heat in oxygen significantly
It is easy to produce in the case where rolling plate surface layer.That is, the oxygen concentration inside the higher layer of the oxygen concentration of hot rolling plate surface and hot rolled plate
Usually there is biggish difference in the cold-workability in lower region, it can be seen that, due to the difference of such oxygen concentration, in cold rolling
When, when cold forming, be easy to produce crackle 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, has been understood fully therewith, this
It is caused in DC slab casting process, and melt surface processing later can also impact the distribution of oxygen concentration.
That is, understood fully superficial layer in DC slab occasionally there are with very high concentration (for example, playing depth 0.5mm from surface
Until the average oxygen concentration of part be oxygen concentration 0.3mass%~0.5mass% higher than the average oxygen concentration of base material or so)
Containing aerobic layer (calling it as oxygen contamination layer below).So oxygen contamination layer is generated it is conceivable that several reasons in steel slab surface,
As one of reason, alternatively it is conceivable to, when in order to take out from extraction chamber by fluid origin slab after casting and open chamber,
The air entered from outside is absorbed by steel slab surface sometimes.In addition, it is contemplated that there is the chamber in casting for some reason
Indoor vacuum degree is not got higher fully or indifferent gas from the vacuum degree around the slab for the high temperature that mold is extracted out especially
The case where residual oxygen-containing gas concentration under body atmosphere is got higher, in these cases, oxygen is sometimes from the atmosphere around slab
It is absorbed by steel slab surface.
Also, if by so the slab of oxygen contamination layer is produced under the premise of not implementing surface cutting processing on surface
It is just supplied to melt surface processing, 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 get higher and will not reduce, 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 such deeper oxygen contamination layer also fails to fully remove in the pickling before cold rolling, and understand
It left behind, if the hot rolled plate is supplied to cold rolling, cold forming, due to the oxygen by the region (remelted solidification layer) of near surface
The difference of cold-workability caused by the difference of the oxygen concentration of concentration and interior zone, is easy to produce crackle.
Herein, in the case where state when DC slab maintains casting, in general, the oxygen concentration of superficial layer (oxygen contamination layer)
It with removing become larger such gradient (oxygen concentration gradient) from private side towards surface, but observes, if at using melt surface
Reason solidifies superficial layer melt-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 until playing surface from inside, oxygen concentration becomes constant.But under the state
Constant oxygen concentration after equalization is apparently higher than the non-polluting region of side close to the inner portion than remelted solidification layer (oxygen contamination layer) (not
The region of the holding raw sheet billet state melt-solidify again) oxygen concentration.It means that in melt surface treated plate
Superficial layer (remelted solidification layer in base (hot rolling blank)；Oxygen contamination layer) and close to the inner portion than the superficial layer between the region of side
Near border, 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) and interior zone between the change dramatically of oxygen concentration of near border do not eliminated in heating of plate blank before hot rolling,
The state is also maintained after hot rolling.In addition, oxygen contamination layer deepens and reaches in hot rolling as previously mentioned, being handled by melt surface
The depth that not can be removed in the pickling of plate.Therefore, alternatively it is conceivable to, in cold rolling after pickling, cold forming, (again due to superficial layer
Melting and solidification layer) and interior zone between near border significant cold-workability difference, be easy with the near border be
Starting point cracks.That is, it can be seen that, the melt surface processing that hot rolling is carried out with blank (slab) is being used to make smooth surface
It is extremely effective for changing, make defect (stomata etc.) the disappearance aspect of superficial layer, but in the case where superficial layer is by oxygen contamination, can be made
At the equalization (homogenizing the oxygen concentration gone from inside towards surface) 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 is easy to cause as described above crackle when cold rolling, cold forming
Problem.
Even in addition, DC slab, maintain the slab of state when casting superficial layer be generally also it is concave-convex serious and
Layer more than defect.In the past, additionally it is possible to expect, remove slab in the way of being removed to the depth of several mm or so by machining
Superficial layer after, implement the processing of foregoing melt surface.Cutting in this case to remove the bumps on surface, defect is
Main purpose, but be also contemplated that, this method is copied, the oxygen contamination layer of DC steel slab surface is removed using machining, later
Implement melt surface processing.In this way, if advancing with machining before melt surface processing removes desurfacing (oxygen contamination
Layer), then can be avoided because foregoing DC casting when oxygen contamination due to cold working, cold forming when crack problem.
However, being cut in the case that the oxygen concentration of the oxygen contamination layer in DC slab is higher and the depth relatively depth of oxygen contamination layer
It cuts depth to also have to deepen, in this case, surface cutting processing needs a large amount of effort and time, and yield rate can also drop significantly
It is low.Thus, if omitting the machining before such melt surface processing or at least making cutting depth shallower, can prevent
Because foregoing DC casting when oxygen contamination due in cold rolling, cold forming when crack, can be with high production rate and low cost
To manufacture the excellent titanium sheet metal of cold-workability.
Thus, problem of the present invention is that, the machining before handling without melt surface is provided or at least makes 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
It rolls, is 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 be improved titanium hot rolled plate manufacture productivity and seek cost
It reduces.
The solution to the problem
In order to solve the above problems, the inventors of the present invention go deep into experimental study repeatedly, as a result, it has been found that: if at melt surface
The stage of titanium plate base before reason reduces the oxygen concentration gradient on the slab thickness direction of the superficial layer moderately, then can
Foregoing project is solved, so as to complete the present invention.
Therefore, basic technical solution (the 1st technical solution) of the invention provides a kind of melt surface processing 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
It is used when manufacturing titanium for the hot rolling of rolling surface, wherein the titanium plate base is by under vacuum or inert gas atmosphere
The titanium plate base that DC slab casting method is obtained, maintains as-cast condition will be from the table on the thickness direction of the titanium plate base
Play d in face1Region until/2 position is set as the 1st region, will be from the d1Play the d in/2 position1Position until
Region is set as the 2nd region, the average oxygen concentration of the base material by the average oxygen concentration in the 1st region relative to the titanium plate base
Increment be set as C1, the average oxygen concentration of the base material by the average oxygen concentration in the 2nd region relative to the titanium plate base
Increment is set as C2, by C1With C2Between poor C1- C2It is set as Cd, at this point, C1For 0.20mass% hereinafter, C2For 0.05mass% with
Under, and CdIt greater than 0 and is 0.15mass% or less.
Also, the 2nd technical solution of the invention is the base in the melt surface processing titanium plate base of the 1st technical solution
On plinth, the CdFor 0.10mass% or less.
Also, the 3rd technical solution of the invention is the melt surface processing titanium in the 1st or the 2nd technical solution
On the basis of slab, the d1In the range of 3.0mm~10.0mm.
In addition, the 4th technical solution of the invention is in any one of the 1st technical solution~the 3rd technical solution technology
On the basis of the melt surface processing titanium plate base of scheme, the surface is eliminated with 3.0mm thickness cutting below.
Also, in the 5th technical solution~the 7th technical solution below, to by melt surface as described above
Implement the processing (melt surface processing) that the melting-based on high density energy rapidly solidifies again and form in the surface of reason titanium plate base
Titanium material for hot rolling provided.
That is, the 5th technical solution of the invention provides a kind of titanium material for hot rolling, wherein the titanium material for hot rolling is in benefit
It is handled with melt surface and forms depth on the surface of the titanium plate base of any one of the 1st technical solution~the 4th technical solution technical solution
Spend d1Remelted solidification layer and by being used when manufacturing titanium as the hot rolling of rolling surface using the surface.
In addition, the 6th technical solution of the invention is the thickness side on the basis of titanium material for hot rolling of the 5th technical solution
Upward oxygen concentration is distributed in the boundary position between the remelted solidification layer and base material from base material towards surface in step-like
Increase.
In addition, the 7th technical solution of the invention is in any one of the 5th technical solution and the 6th technical solution technology
On the basis of the titanium material for hot rolling of scheme, averaged oxygen of the average oxygen concentration of the remelted solidification layer relative to the base material
The increment of concentration is 0.1mass% or less.
The effect of invention
It using the present invention, is handled using melt surface and forms remelted solidification layer on the surface of titanium plate base, and by with institute
The 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 before melt surface processing or even if making this
Cutting output is smaller, can also prevent from as described above implementing to crack etc. the bad situation of processing, therefore, energy when cold working
Enough to omit cutting or reduce cutting output, therefore, it is possible to realize the raisings of productivity, the reduction of manufacturing cost.
Detailed description of the invention
Fig. 1 be schematically show using the DC casting under vacuum the method for manufacturing titanium plate base an example it is simple
Schematic diagram.
Fig. 2 is the schematical perspective view for indicating the example for the case where implementing melt surface processing to titanium plate base.
One example of the case where Fig. 3 is titanium slab surface layer when being directed to the implementation melt surface processing of titanium plate base is at it
The schematic diagram that sectional position is indicated.
Fig. 4 is the thickness direction for accordingly indicating to maintain with slab section at the sectional position of the titanium plate base of as-cast condition
On oxygen concentration distribution an example schematic diagram.
Fig. 5 A is the oxygen concentration distribution on the thickness direction at the sectional position as the titanium plate base for maintaining as-cast condition
An example and by the portion IV of Fig. 4 amplification indicate schematic diagram.
Fig. 5 B is the stage indicated carried out after melt surface processing to titanium plate base, becomes 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 is to indicate to carry out titanium plate base thickness in the stage after melt surface processing and hot rolling, at sectional position
Spend the schematic diagram of an example of the oxygen concentration distribution on direction.
Fig. 5 D is to indicate 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 at position.
Fig. 6 A is the thickness at the sectional position with scale identical with Fig. 5 A to indicate to maintain the titanium plate base of as-cast condition
Spend the schematic diagram of the comparative example of the oxygen concentration distribution on direction.
Fig. 6 B is to indicate to carry out titanium plate base the oxygen concentration point after melt surface processing with scale identical with Fig. 6 A
The schematic diagram of the comparative example of cloth.
Fig. 7 be by the thickness direction at the sectional position of titanium plate base of the invention oxygen concentration distribution and melt surface at
One example of the concentration distribution after reason with the oxygen concentration of the previous titanium plate base with oxygen contamination layer distribution and melt surface
The schematic diagram shown in mode that concentration distribution that treated compares.
Specific embodiment
In the following, explaining embodiments of the present invention in detail referring to attached drawing.
Firstly, before illustrating melt surface processing titanium plate base of the invention, for manufacture melt surface processing titanium
Even if the method for slab, with the high density energies such as electron beam or plasma heat source under vacuum or inert gas atmosphere melting titanium
Melting raw material and continuously cast with predetermined length rectangular in cross-section shape slab (slab) DC slab casting method (direct pouring
Method), illustrate to apply the example in the case where electron-beam smelting referring to Fig.1.
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, irradiate rifle 12 using electron beam to irradiate
Electron beam 3 melts the melting raw material in siege 2.Then, obtained titanium melt 4 is continuously poured into DC slab casting
Water cooling Copper casting mould 6, i.e. opening and the water cooling casting in bronze of horizontal cross-section rectangular (including the case where that corner is formed with chamfering) up and down
In mould 6, the water cooling Copper casting mould 6 of the DC slab casting is disposed in casting-extraction chamber 5 top.In addition, at this point, general next
Say, in order to keep the titanium melt 4 in mold 6 surface temperature, other than the electron beam 3 of melting, also in mold 6
The surface irradiating electron beam 7 of titanium melt 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 gone up and down) 8 by making the lower section being disposed in casting-extraction chamber 5
Drop, so that the titanium solidified in mold 6 is continuously extracted out downwards, obtains in the extraction chamber 5B described as follows as a result,
Section be rectangle (including the case where that corner is formed with chamfering) and be predetermined length titanium plate base 10.
Herein, casting-extraction chamber 5 becomes the extraction chamber of the lower section of the casting chamber 5A and mold 5 that will surround mold 6
Room 5B connects the structure of setting in the up-down direction, and the extraction chamber 5B of lower part is configured to sometimes, in the casting for completing predetermined length
Leave the casting chamber 5A on top after making, and with extraction member 6 together from original position (position when casting) to side (such as
The left of Fig. 1) it is mobile.In this case, in general, in order to keep casting chamber 5A vacuum state, to casting chamber 5A
Type variable demarcation plate (valve plate) (not shown) or setting are inserted between extraction chamber 5B has type variable demarcation plate (valve plate)
Shorter lock chamber.In addition, be configured to, the other side of the position (original position) of the extraction chamber 5B in casting (such as Fig. 1
Right) it is equipped with another extraction chamber (chamber with another extraction member) (not shown), in the titanium plate for completing predetermined length
After the casting of base 10, as the extraction chamber 5B of original position is moved to side (such as left of Fig. 1), above-mentioned another extraction chamber
Room reaches the downside of casting chamber 5A.
In addition, herein, space and casting-in the case where type variable demarcation plate (valve plate) is opened, in melting chamber 1
Space in extraction chamber 5 is connected by the gap etc. around mold 6.Also, it on the top of such as melting chamber 1, borrows
Exhaust-assisting pipe 9a is connected with vacuum pump 9, to carry out to the space in the space and casting-extraction chamber 5 in melting chamber 1
Vacuum evacuation.Thus, the melting and casting of titanium is substantially to carry out under vacuum evacuation.But it in fact, can also lead sometimes
Enter the thin inert gas of minute quantity.
The casting of the titanium plate base 10 of predetermined length is completed in casting-extraction chamber 5 as described above, and is placed several
Time and so that titanium plate base 10 is carried out a degree of cooling, be inserted into type variable demarcation plate later, the extraction chamber 5B of lower part leaves
The casting chamber 5A on top is simultaneously mobile to the left of such as Fig. 1 together with titanium plate base 10 and extraction member 6, to complete 1 batch
Melting and casting.When the extraction chamber 5B of lower part so leaves the casting chamber 5A on top and moves, chamber 5B is extracted out
Interior vacuum evacuation is interrupted, and after further cooling to temperature appropriate, extraction chamber 5B is opened at atmospheric pressure.
At the same time or later, such as another extraction chamber positioned at right side (has another extraction member, carries out in advance
The extraction chamber of vacuum evacuation) it is moved to the lower position of casting chamber 5A, which is connected to casting chamber 5A, then
Secondary opening type variable demarcation plate, casting-extraction chamber 5 is interior to be connected with melting chamber 1, is exhausted using vacuum pump 9, with
The melting and casting of standby next batch.
Next, illustrating to implement the titanium plate base 10 obtained by foregoing melting and casting referring to Fig. 2, Fig. 3
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 casting
Slab extraction direction) LD extend 4 face 10A~10D in wider two faces 10A, 10B (with chamfering 11 face) become
Rolling surface when hot rolling.Therefore, melt surface processing at least is implemented to wider two faces 10A, 10B with the chamfering 11.
It is of course also possible to be not only to implement melt surface processing to wider two faces 10A, 10B, still carried out to side 10C, 10D
Melt surface processing, thereby, it is possible to enjoy the advantage for omitting cutting etc., but herein, be set as to wider two faces 10A, 10B into
Row melt surface handles and is unfolded to illustrate.
Specifically, firstly, using electron beam irradiation rifle 13 to wider 1 face 10A in the outer surface of titanium plate base 10
Surface irradiating electron beam, melt the superficial layer of face 10A rapidly.At this point, making electron beam irradiation rifle 13 on one side continuously
It is mobile perhaps continuously move rectangular casting blank 10 to make to melt position on one side (or short along the length direction LD of titanium plate base 10
Edge direction) it continuously moves.The melting layer on 10 surface of titanium plate base at this time is indicated using appended drawing reference 16a in Fig. 3.
If carrying out electron beam while making electron beam irradiation rifle 13 relative to titanium plate 10 relatively continuous moving of base
Irradiation, then as shown in Figure 3, the melting layer 16a of the part after completing irradiation can be by from base material (inside of titanium plate base 10)
Heat extraction and be cooled, if reach setting temperature hereinafter, if melting layer 16a can solidify and become remelted solidification layer 20.
In addition, generating the hot shadow for being heated to beta transformation point temperature (about 900 DEG C) or more due to the heat affecting of melt surface processing
Sound portion (HAZ) 18.Later, which is cooled by from the heat extraction of base material (inside of titanium plate base 10), makes
The heat affected zone (HAZ) 18 reaches beta transformation point temperature hereinafter, to form heat affected layer 22.
In the present specification, the remelted solidification layer 20 and heat affected layer 22 are referred to as melt surface process layer 21 together.
Also, if the melting-of the whole region (or region to be treated) for 1 face 10A of 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, surface irradiating electron beam to titanium plate base, if the surface is heated to
The temperature more than fusing point (usually 1700 DEG C or so) of industrial titanium, then the superficial layer of the plate face 10A of titanium plate base 10 is melted
To depth corresponding with heat input.That is, playing depth d in a thickness direction from surface1Position until region be melted,
By later form depth d in a thickness direction and solidification again1Remelted solidification layer 20.In addition, being also formed with depth d2's
Heat affected layer 22.Thus, melt surface processing in this way, coarse cast sturcture is transformed into the whole of small phase-change organization
The depth of a 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
d1Usually in the range of 3mm~10mm.
Fusion penetration based on electron beam irradiation mainly has relationship with heat input, therefore can obtain above-mentioned melt to become
Melt depth d1The mode of such heat input selects electron beam irradiation condition.In fact, according to the thickness (thermal capacitance of slab
Amount), slab base material temperature, the cooling condition of slab base material side etc., required heat input is also different, therefore, for obtaining
The heat input for stating fusion penetration cannot unify determination, but usually by per unit area (every 1cm2) heat input be set as 80J
~300J or so.In addition herein, the electron beam irradiation condition as the heat input for influencing per unit area has the defeated of irradiation rifle
Power and beam diameter out, it is also mobile fast on one side making to irradiate rifle when being irradiated while rifle continuously moves as mentioned above
(irradiation position movement speed) etc. is spent, suitably they are set and ensures above-mentioned heat input.
The titanium plate base as described above for being carried out melt surface processing is as hot rolling blank by heating stove heating appropriate
To more than hot rolling start temperature, then, which is become the hot rolled plate of required plate thickness by hot rolling.Also, the hot rolling
Plate is decreased to product plate thickness by cold rolling thickness, and be carried out annealing after being carried out the processing of the descales such as pickling.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 slab for maintaining as-cast condition) 10 obtained by melting and casting, thickness
As direction section is as illustrated in FIG. 4, on the surface of the titanium plate base 10 there are oxygen contamination layer 10P, the oxygen contamination layer 10P with than
It is more than the oxygen concentration height such as 0.1mass% degree of base material part (not being carried out the interior zone of melt surface processing) highly concentrated
Degree is contained sometimes with the high concentration more than high 0.3mass%~0.5mass% degree of oxygen concentration than base material part containing aerobic
Oxygen.The oxygen of oxygen contamination layer 10P is mainly the oxygen of the atmosphere in the outside from slab, and absorption and inside from oxygen-containing gas are expanded
It dissipates, therefore, oxygen concentration in oxygen contamination layer 10P, which has, to be gone from steel slab surface towards private side and become smaller that (oxygen is dense for such gradient
Spend gradient).In addition, in the present specification, oxygen contamination layer 10P refers to that oxygen concentration is 0.05mass% higher than the oxygen concentration of base material
Above region, than the average oxygen concentration C of base material in the oxygen gradient on slab thickness direction in e.g. leisure Fig. 40It is high
The oxygen concentration C of 0.05mass% or moreq(=C0+ 0.05mass%) position PqPlay the region until steel slab surface.
Herein, in foregoing electron-beam smelting casting, cooling period in melting and casting and later
In, the space in melting chamber 1 and casting-extraction chamber 5 is maintained vacuum originally, therefore titanium plate base should be unable to be made to produce
Raw oxygen contamination.However, in fact, producing oxygen contamination layer 10P mostly.
Although as already mentioned like that, making it is conceivable that so generating oxygen contamination layer in steel slab surface has several reasons
For one of reason, alternatively it is conceivable to, after the titanium plate base for casting 1 batch, when keeping casting-extraction chamber open, outside enters
Air in oxygen absorbed sometimes by steel slab surface.Especially, the titanium plate base when keeping casting-extraction chamber atmosphere open
Temperature also in high temperature in the case where, be easy to be absorbed by titanium plate base from the external oxygen entered, so that oxygen contamination becomes serious.
In addition, it is contemplated that for some reason, the indoor vacuum degree of chamber in casting, especially from after mold extraction
High temperature slab around vacuum degree do not become sufficiently high in the case where, steel slab surface is from the atmosphere around slab sometimes
Absorb oxygen.In particular, in previous common chamber, as shown in Figure 1, in order to prevent the melting of melting raw material when oxygen inhale
It receives, for being usually provided in 1 side of melting chamber to the vacuum 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 is especially extracted out in chamber 5B
The vacuum degree in space do not become sufficiently high sometimes, thus, in extraction chamber 5B, oxygen containing residual gas is by high temperature sometimes
Titanium plate base 10 absorbs.
Also, be also contemplated that one the reason is that, can adsorb when opening chamber from the external oxygen entered, oxygen-containing gas or
Person is attached to casting-extraction chamber 5 inner wall, outer surface of mold 6 etc., and is not carrying out what adequately exhaust vacuumized
In the case of by the Surface absorption of the slab of high temperature.Regardless of any reason, can expect, it is the oxygen of the indoor atmosphere of chamber, oxygen-containing
The concentration of gas is unexpectedly got higher, and produces oxygen contamination layer in steel slab surface.
Also, if by so the slab of oxygen contamination layer is produced under the premise of not implementing surface cutting processing on surface
(not removing oxygen contamination layer namely) is just supplied to melt surface processing, to melt surface treated slab (hot rolling blank) into
Row heating and hot rolling and hot rolled plate is made, and if cold-reduced sheet or cold rolled annealed plate is made to its further progress cold rolling, then
Can as has been described generate cold rolling when, crack problem when cold forming.That is, it is contemplated that after melt surface processing, it is still remaining
The higher state of the oxygen concentration of the superficial layer of slab (there are the states of oxygen contamination layer), if further using the slab as hot rolling
It is heated with blank, then the hot rolled plate that the oxygen concentration of superficial layer can only get higher without reducing, after hot rolling also maintains superficial layer
The higher state of oxygen concentration, the oxygen concentration of superficial layer when due to cold rolling, when the cold forming of cold-reduced sheet or cold rolled annealed plate
And the difference of processability caused by the difference of the oxygen concentration of interior zone, is easy to produce crackle.
As being specifically described referring to Fig. 5 A~Fig. 5 D from slab melting and casting play melt surface processing, and then to
The varying motion of until hot rolling acid-cleaning, oxygen contamination layer oxygen concentration distribution.
It in fig. 5, will be on the slab thickness direction of the titanium plate base (blank) 10 shown in Fig. 4 that DC as-cast condition be maintained
Oxygen concentration distribution a part, i.e. surface 10A nearby (the IV circle portion of Fig. 4) oxygen concentration distribution amplification expression.In addition,
In Fig. 5 B, benefit is shown by a solid line to titanium plate base implementation table be distributed with oxygen concentration shown in Fig. 5 A, to maintain as-cast condition
The oxygen concentration of slab after the melt process of face is distributed.In addition, the dotted line in Fig. 5 B indicate Fig. 5 A it is shown in solid, maintain casting
Make the titanium plate base of state oxygen concentration distribution, i.e. melt surface processing before oxygen concentration be distributed.Also, it in figure 5 c, shows pair
Oxygen concentration distribution shown in solid with Fig. 5 B, melt surface treated slab the carries out hot rolled plate after hot rolling oxygen
Concentration distribution.In addition, showing in figure 5d dense to the oxygen after the hot rolled plate implementation pickling being distributed with oxygen concentration shown in Fig. 5 C
Degree distribution.
As shown in Figure 5A, for maintaining the oxygen concentration of the slab (blank) of as-cast condition, in the superficial layer of the slab
In go and become larger towards steel slab surface from inside (the base material side inside blank).Also, on the surface, the maximum value of oxygen concentration
C max1 sometimes up to 0.5% or more.
The titanium plate base that as-cast condition is maintained to such is implemented melt surface treated that state indicates in figure 5B.
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 superficial layer of high density energy and utilizing this
Energy carries out action of forced stirring to the melt in molten bath, and therefore, oxygen is flowed because of stirring in molten bath, and the oxygen concentration in melting layer is real
Now equalize, as a result, the oxygen concentration gradient before melt surface processing substantially disappears, remelted solidification layer after melting
(depth d is played from surface1Until region) in 20, oxygen concentration reaches generally uniform.Thus, relative in not oxygen contamination
The substantially uniform oxygen concentration C in portion region (base material)0(usually 0.04mass%~0.2mass% or so), remelted solidification
It is in step-like state (the oxygen concentration C got higher that the oxygen concentration of layer 20, which becomes,m).That is, in melt surface treated slab, (hot rolling is used
Blank) in, superficial layer (remelted solidification layer 20) and specific surface layer close to the inner portion the near border between the region of side (it is stringent come
Say, the near border between the remelted solidification layer 20 in melt surface process layer and heat affected layer 22), oxygen concentration is in step-like
Sharp change.
Also, in addition, as make in melt surface is handled processing before superficial layer oxygen concentration equalization as a result,
In substantially the entire area on thickness direction, the value C of the oxygen concentration of the remelted solidification layer 20 after melt surfacemBefore processing
The maximum value C on surface max1 is small, but the obvious average oxygen concentration C than the not interior zone of oxygen contamination0It is high.By Fig. 5 A it is found that this
It is meant that being handled by melt surface, average oxygen concentration C of the oxygen concentration than the interior zone of not oxygen contamination0High region (oxygen
Concentration CmRegion) greatly expand to the private side of plate.In addition, by the oxygen concentration C of remelted solidification layer 20mRelative to inside
The average oxygen concentration C in region (base material part)0Increment be set as Δ Cm(=Cm- C0)。
Implement melt surface treated slab as hot rolling blank heating and is applied hot rolling.Utilize the solid line of Fig. 5 C
Oxygen concentration distribution after showing hot rolling.Further, since whole thickness is reduced because of hot rolling, and therefore, the slab before hot rolling
In be d, d1、d2Part reduced respectively to d ', d by hot rolling1′、d2′.In addition, in hot rolled plate, in the slab before hot rolling
Utilize PqThe position of label, i.e. with the oxygen concentration C than base material0The oxygen concentration C of high 0.05mass%q(=C0+ 0.05mass%) phase
Corresponding position mark is Pq′。
Due to before hot rolling heating and hot rolling usually carry out in an atmosphere, 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 35% degree of oxygen concentration).In general, after hot rolling,
Carry out pickling, and by very thin, the thickness d on surface3Layer (in general, thickness d3For the layer of 0.03mm~0.1mm or so) dissolution
Removal, the layer of the high oxygen concentration on the surface usually generated in heating-hot rolling as a result, are removed.After such progress pickling
Oxygen concentration distribution indicates 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 institute
Show, the oxygen concentration distribution (step-like distribution in a thickness direction) that the melt surface before hot rolling heating generates due to processing is inclined
It is remained substantially constantly to meeting.That is, in the state of hot rolled plate after pickling, on the surface for having carried out melt surface processing
Boundary position P1 between the region of remelted solidification layer 20 in melt process layer and the region for leaning on intralamellar part than the region is attached
Closely, oxygen concentration also can sharp change.Further, it is possible to expect, if the difference of such oxygen concentration is larger, in cold-workability side
Face can also generate biggish difference in superficial layer and interior zone, as described above, in cold rolling, cold forming, can generate and split
Line, removing.
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
The depth of layer 10P from steel slab surface plays oxygen concentration as Cq(=C0+ 0.05mass%) position PqUntil depth it is deep.
In addition, the depth d of the remelted solidification layer 20 in melt surface process layer 211Both can be greater than might be less that oxygen
The depth of pollution layer 10P, i.e. from steel slab surface play oxygen concentration be Cq(=C0+ 0.05mass%) position PqUntil depth,
But the in fact, desirably depth d of remelted solidification layer 201It is C greater than oxygen concentration is played from steel slab surfaceqPosition PqFor
Depth only.
In conclusion it is contemplated that molten due to implementing surface there are the oxygen contamination layer on the surface of titanium plate base and to the slab
The varying motion for melting the oxygen concentration distribution of superficial layer when processing, 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, many experimental studies have been repeated in the inventors of the present invention, as a result, it has been found that a kind of processing of melt surface is used
Titanium plate base is to form depth d on the surface of titanium plate base using melt surface processing1Remelted solidification layer and by with
What the surface was the hot rolling of rolling surface to use when manufacturing titanium, wherein, will be from the table on the thickness direction of titanium plate base
Play d in face1Region until/2 position is set as the 1st region, will be from the d1Play the d in/2 position1Position until
Region is set as the 2nd region, the average oxygen concentration of the base material by the average oxygen concentration in the 1st region relative to the titanium plate base
Increment be set as C1, the average oxygen concentration of the base material by the average oxygen concentration in the 2nd region relative to the titanium plate base
Increment is set as C2, by C1With C2Between poor C1- C2It is set as Cd, at this point, if C1For 0.20mass% or less, C2For
0.05mass% or less and CdGreater than 0 and be 0.15mass% hereinafter, then melt surface treated 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 not causing dysgenic journey to cold-workability
Degree can be effectively prevented and crack in cold rolling as the hot rolled plate after melt surface as described above processing and hot rolling,
It is cracked in addition it is possible to be effectively prevented when carrying out cold forming processing to cold rolled annealed plate.
Herein, it also becomes larger and is unsatisfactory for for producing the oxygen concentration gradient of the higher oxygen contamination layer of oxygen concentration and superficial layer
Slab (comparing with slab) in the case where the condition, using with it is in slab of the present invention shown in Fig. 5 A, at melt surface
This is compared the rank before the melt surface processing with slab by the identical scale that the thickness direction oxygen concentration in the stage before reason is distributed
Thickness direction oxygen concentration distribution in section indicates in fig. 6.In addition, using in slab of the present invention shown in Fig. 5 B, surface
Thickness direction oxygen concentration in stage before melt process, which is distributed identical scale and compares this, carries out melt surface with slab
Treated, and the distribution of thickness direction oxygen concentration indicates 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, comparing with slab and slab of the present invention
Between be not present difference, can be considered as it is identical, therefore, compared with use the related Fig. 6 A of slab, Fig. 6 B in, and with plate of the present invention
Similarly, internal average oxygen concentration is represented as identical value C by the related Fig. 5 A of base, Fig. 5 B0。
Herein, also become for the oxygen concentration gradient for producing 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 where 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 before handling melt surface
Thickness direction oxygen concentration distribution in the stage of concentration distribution and melt surface treated slab (hot rolling blank) carries out pair
The mode of ratio is shown.
As shown in Figure 6A, comparing in slab, along slab thickness direction to remelted solidification layer 20 from steel slab surface
Depth d 11/2 (i.e. d1/ 2) average oxygen concentration of region (the 1st region) R1 until position relative to base material averaged oxygen
Concentration C0Increased increment C1', with from d1It rises along slab thickness direction to the depth d for being equivalent to remelted solidification layer/2 position1
Position until region (the 2nd region) R2 average oxygen concentration relative to base material average oxygen concentration C0Increased increment C2' it
Poor Cd' (=C1'-C2') more than 0.15mass%.This is illustrated with dashed lines in Fig. 7 to compare in slab, melt surface
Thickness direction oxygen concentration distribution before reason.In addition, utilizing Cmax1 ' shows the maximum of superficial layer (oxygen contamination layer) in this case
Oxygen concentration (oxygen concentration of surface location).
In addition, using slab for comparing, benefit, which is illustrated with dashed lines, in Fig. 7 carries out melt surface 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 base material on thickness direction, which becomes,
Cloth.Also, in depth d1Position (boundary position between remelted solidification layer 20 and base material) near, oxygen concentration is in thickness
From C on direction0Sharply and significantly it is changed to Cm′。
On the other hand, in slab of the present invention, the average oxygen concentration of the 1st region R1 relative to base material average oxygen concentration C0
Increment C1With the average oxygen concentration of the 2nd region R2 relative to base material average oxygen concentration C0Increment C2Between poor CdFor
0.15mass% or less.Thickness in the slab of the present invention, before melt surface processing is shown using double dot dash line in Fig. 7
The distribution of direction oxygen concentration.In addition, utilizing C max1 shows the maximum oxygen concentration (table of superficial layer (oxygen contamination layer) in this case
The oxygen concentration of face position).
Herein, with the average oxygen concentration that is unsatisfactory for the 1st region R1 relative to base material oxygen concentration C0Increased increment and the 2nd
The average oxygen concentration of region R2 relative to base material oxygen concentration C0Poor C between increased incrementdFor 0.15mass% item below
The case where comparison slab of part, comparing (that is, use in plate, Cd' > 0.15mass%) it compares, meet above-mentioned 1st region R1's
Average oxygen concentration relative to base material average oxygen concentration C0The average oxygen concentration of increased increment and the 2nd region R2 relative to mother
Material average oxygen concentration C0Poor C between increased incrementdFor 0.15mass% condition below slab of the present invention the case where (i.e.
Cd≤ 0.15mass%) under thickness direction on oxygen concentration gradient (inclination) it is smaller.In addition, as previously mentioned, if 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 dotted line to Fig. 7 and use slab；Melt surface processing
Before) and double dot dash line (slab of the present invention；Melt surface processing before) be compared it will be apparent that, the surface location of slab of the present invention
Oxygen concentration (maximum oxygen concentration) C at placemax1 lower 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 until part contained by total oxygen amount
Depth d is played from surface with slab also less than comparing1Position until part contained by total oxygen amount.
Also, (plate of the condition is met for the slab of the present invention being distributed with oxygen concentration shown in above-mentioned chain-dotted line
Base), the solid line of Fig. 7 is shown with depth the d (=d away from surface1+d2) carry out on melt surface treated slab thickness direction
Oxygen concentration distribution.In the case where the slab of the present invention, as the oxygen concentration distribution on melt surface treated thickness direction
Tendency, also compared with the oxygen concentration distribution on the melt surface of slab treated thickness direction similarly, in depth d1
Remelted solidification layer 20 in, oxygen concentration on thickness direction realizes equalization, becomes the oxygen concentration C of constantm, relative to
Base material oxygen concentration C0Increased increment Delta CmAlso reach constant in a thickness direction.That is, the oxygen concentration on thickness direction is distributed
As step-like distribution.But depth d is played near surface in slab of the present invention1Position nearby until part
In constant oxygen concentration CmLess than melt surface treated compare in slab (dotted line of Fig. 7) near surface
Play depth d1Position nearby until part in constant oxygen concentration Cm′.The reason is that as previously mentioned, at this
In invention slab, depth d is being played from surface1Position until part contained by total oxygen amount less than comparing in slab
Playing depth d from surface1Position until part contained by total oxygen amount.Also, it is found that in depth d1Position
Near (remelted solidification layer and than the boundary position between the base material region of the remelted solidification layer in the inner part), oxygen concentration exists
In step-like from C on thickness direction0Variation is Cm, but the degree of the variation, i.e. oxygen concentration increment Delta Cm(=Cm- C0) be less than than
Compared with in slab from C0To CmDegree (the oxygen concentration increment Delta C of ' variationm'=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
Change dramatically mitigated.
As described above, it by keeping the oxygen concentration gradient in the plate thickness direction in superficial layer smaller, can mitigate based on surface
The remelted solidification layer of melt process and oxygen concentration than near border between the region of remelted solidification layer in the inner part
Variation.Also, the tendency is also maintained after heating before implementing hot rolling, after further implementation hot rolling, remelted can will be coagulated
Gu the increased increment of the oxygen concentration relative to base material of the oxygen concentration of layer inhibits smaller.That is, also can in the state of hot rolled plate
Enough mitigate remelted solidification layer and sharply than the oxygen amount at the near border between the region of remelted solidification layer in the inner part
Variation.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 reduction a possibility that cracked in cold rolling, in addition, after cold rolled annealed, when carrying out cold forming processing
A possibility that cracking reduction.
More than, in the present invention, the degree as the oxygen concentration gradient on the thickness direction in the superficial layer for indicating slab
The index of (inclination), using related with the 1st region R1 relative to base material average oxygen concentration C0Increased increment C1With with the 2nd area
Domain R2 is related relative to base material average oxygen concentration C0Increased increment C2Between poor Cd, by difference Cd(=C1- C2) be limited in
0.15mass% or less.
Herein, if there are above-mentioned difference in oxygen concentration C in the superficial layer of slabdIt is biggish dense more than as 0.15mass%
Gradient is spent, then melt surface treated remelted solidification layer and than the boundary between the region of remelted solidification layer in the inner part
The variation of neighbouring oxygen concentration become larger (for example, under melt surface treated state, the oxygen concentration C of remelted solidification layerm's
Relative to base material average oxygen concentration C0Increased increment Delta CmMore than 0.1%).As a result, being 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, removing.
In addition, related with the 1st region R1 relative to base material oxygen concentration C0Increased increment C1More than 0.2mass%'s
In the case of or it is related with the 2nd region R2 relative to base material oxygen concentration C0Increased increment C2In the case where 0.05%, table
Remelted solidification layer after the melt process of face and than the oxygen at the near border between the region of remelted solidification layer in the inner part
The variation of concentration become larger (for example, under melt surface treated state, the oxygen concentration C of remelted solidification layermRatio base material
Oxygen concentration C0Increased increment Delta CmMore than 0.1%).As a result, being 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 remove.
In addition, if can be by the poor C of the increment of the oxygen concentration before the processing of above-mentioned melt surfacedInhibit in 0.10mass%
Hereinafter, then can be further improved effect of the invention.
In addition, the depth as the remelted solidification layer in the melt surface processing applied to slab is (away from the original before processing
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, it is utilized with being unable to fully and carries out melt surface processing and the smoothing of the superficial layer realized, surface
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 will not become larger again, only can unnecessarily incur the increase of energy cost, the reduction of productivity.
In addition, the depth in the 1st region of the benchmark of the thickness direction concentration gradient of the superficial layer as slab, the 2nd region
According to the depth d for the surface melt process implemented later1And it is set as depth d 11/2, thus, each region it is specific
Depth (d1It/2) is 1.5mm~5mm or so.
In addition, as previously mentioned, in general, if in advance limitation slab surface layer thickness direction on oxygen concentration gradient,
As having described, the maximum oxygen concentration of surface location also becomes smaller, and therefore, adds even if not implementing cutting before melt surface processing
Work can also obtain function and effect as described above.But according to circumstances, it is also 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 surface section, the concentration gradient on the depth direction of oxygen will not become
Change, but since cutting eliminates high oxygen concentration portion, total oxygen amount of remelted solidification layer tails off, above-mentioned 1st region R1's
The difference of the oxygen concentration of oxygen concentration and the 2nd region R2 becomes smaller, though in each region relative to base material oxygen concentration C0It is increased
Increment C1、C2Poor CdIt is not in 0.15mass% situation below, can in the state of before the cutting for maintaining as-cast condition yet
Above-mentioned difference C is enough obtained using machiningdFor 0.15mass% slab below.But if the cutting depth on surface layer is super
3.0mm is crossed, then the burden of machining is made to become larger and productivity may be hindered, therefore, in the case where being cut, makes surface layer
Cutting depth be 3.0mm or less.
In manufacture (melting and casting) melt surface titanium plate base of the 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 be using such various sides shown in following A~C
Method.In addition, countermeasure A be primarily used for preventing melting and casting after atmosphere opening when oxygen contamination method.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 combined 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 be titanium phase transition temperature i.e. 900
In the case where more than DEG C degree, it is easy to produce because caused by atmosphere opening, atmosphere enters in chamber, oxygen absorbed by slab
The case where.Therefore, after the slab of melting and casting predetermined length, reach 900 DEG C or so or less in the surface temperature of slab
Just carry out atmosphere opening.Accelerated at this point, slab both can have been placed in chamber regardless of, or raising productivity
It is cooling.For example, it can be arranged the cooling-part for cooling down slab in extraction chamber in advance, be 900 DEG C in surface temperature
Atmosphere opening is carried out in the state that left and right is following.As the cooling-part, for example, can apply in advance will be cold after internal water cooling
But plate is close to the state of slab setting etc..Alternatively, it is also possible to be, before atmosphere opening, the cryogenic gas such as inert gas are utilized
To replace the indoor atmosphere of chamber, make surface temperature in advance and become 900 DEG C of degree hereinafter, steel slab surface reach 900 DEG C it is below
Atmosphere opening is carried out at the time of low temperature.
Countermeasure B: as has been explained above, in general, being used for being mainly used for remaining melting chamber 1 into the purpose of vacuum
The vacuum pump 9 (referring to Fig.1) being exhausted in chamber away from the farther away position of casting-extraction chamber 5 mostly to arrange
The mode of gas is attached.In this case, as shown in the chain-dotted line for example using Fig. 1, relative to the true of melting chamber
The vacuum pump 9 of idle discharge gas independently, is arranged the 2nd vacuum pump 91, the exhaust pipe 91a of the 2nd vacuum pump 91 is connected to casting
The side extraction chamber 5B making-extracting out 5 side of chamber, especially opened to outer gas, so that casting when improving melting and casting is taken out
Vacuum degree in chamber 5 out.
Countermeasure C: in melting and casting, in order to reduce the partial pressure of the oxygen in atmosphere, oxygen-containing gas, such as point of such as Fig. 1
Shown in scribing line like that, in advance the higher target of absorbability of the setting oxygen such as inner surface of extraction chamber 5A or oxygen-containing gas,
Such as the component 92 by formation such as titanium, zirconiums.It in addition to this, can also for the indoor vacuum degree of chamber when improving casting smelting
With the vacuum pump for using exhaust capacity bigger.The indoor gas of chamber when alternatively, it is also possible to be applied in combination for by casting smelting
The component of close property raising etc..
Herein, the industrial pure titanium for constituting titanium plate base of the invention includes 1 class~4 classes and phase therewith by JIS standard
Industrial pure titanium as defined in Grade1~4 of corresponding ASTM standard, 37025,37025, the 37025 of DIN standard.
That is, it can be said that the industrial pure titanium in the present invention as object in terms of quality % comprising C:0.1% or less, H:0.015% or less,
O:0.4% or less, N:0.07% or less, Fe:0.5% are hereinafter, remaining is Ti.In turn, a little platinum family member is added among them
Element, be known as improve (improvement) pure titanium highly corrosion resistant alloy ( ASTM Grade 7,11,16,26,13,30,33 or and it
Corresponding JIS class) be also regarded as within industrial pure titanium in the present invention.
In addition, the size of surface treatment titanium plate base 10 of the invention directly for the size of hot rolling if can not then have
It is particularly limited to, but as hot rolling application coil rolling (coil rolling) and the hot rolling that manufactures plate thickness 3mm~8mm or so
In the case where 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.
When actually using titanium material for hot rolling of the invention, implements hot rolling and the hot rolled plate of desired plate thickness 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 plate thickness 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, in the range at a temperature of start hot rolling,
According at a temperature of end hot rolling of the ability of milling train more than room temperature.
In the following, illustrating the embodiment of the present invention together with comparative example.
Embodiment
Test example 1
Using the pure titanium of JIS1 class as melting raw material, DC casting is carried out by electron-beam smelting using equipment as shown in Figure 1
It makes, having obtained section is about 1300mm wide × about 400mm thickness × about 7500mm long titanium plate base.Casting speed is
2ton/h。
In melting and casting, in order to inhibit a part slab (No.1~No.6 of table 1) superficial layer oxygen concentration,
Apply the countermeasure of any one in the countermeasure A~countermeasure C or more.It is unreal for the slab (No.7 of table 1) of a part
It is applied to the countermeasure for inhibiting the oxygen concentration of superficial layer.
In addition, for the DC slab manufactured with condition identical with No.7, in the advance of next melt surface processing
It has gone surface cutting (cutting depth is 0.5mm~2.5mm), the slab of No.8~No.12 of table 2 is made.
Later, slab is continuously moved on one side, is irradiated on one side using electron beam and wider two faces of slab is carried out
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
The electron beam of 2.5cm keeps other electron beam irradiation conditions (slab movement speed when the output power of electron beam, irradiation, every
The heat input etc. of 1cm) variation, make fusion penetration (depth of remelted solidification layer) d away from surface location of slab1Variation.
In above process, for the wider face of each titanium plate base before melt surface processing, using for section
The oxygen concentration of the superficial layer in the face and its distribution are quantitatively investigated in EPMA analysis (X-ray microanalysis instrument).That is, adjusting
The oxygen concentration C on surface is looked intomax, base material part average oxygen concentration C0, also, the mesh that the melt surface carried out later is handled
The depth for marking the remelted solidification layer of (predetermined) is set as d1, depth d is played to from the surface1Region (the 1st area until/2
Domain R1) oxygen concentration the average oxygen concentration C relative to base material part0Increment C1With from depth d1/ 2 play d1Until area
The average oxygen concentration C relative to base material part of the oxygen concentration in domain (the 2nd region R2)0Increment C2It is investigated.
In addition, for the example (No.8~No.12) for having carried out surface cutting before carrying out melt surface processing, investigation
Each oxygen concentration after cutting.
By the oxygen concentration of superficial layer related with each slab No.1~No.12 before the processing of these melt surfaces and its distribution
Investigation result indicate in Tables 1 and 2.
On the other hand, for melt surface treated each titanium plate base (for titanium material for hot rolling；Carrying out surface cutting
In the case where for the blank after the cutting) wider face, investigated the oxygen concentration C on surfacemax, the averaged oxygen of base material part it is dense
Spend C0, d is played to from surface1Position until (i.e. remelted solidification layer play bottom from surface until) part oxygen it is dense
The average oxygen concentration C relative to base material part of degree0Increment Delta CmIt is investigated.It the results are shown in table 3.
Also, titanium material for hot rolling after the completion of by melt surface processing obtained as described above is inserted into 800 DEG C
Furnace in after, carry out about 240 minutes heat, with continuously hot rolling band and strip rolling mill manufacture 5mm thickness hot rolled strip roll up, across wrap
Containing nitric acid-hydrofluoric acid continuous acid-washing production line, every one side dissolution has pruned about 40 μm.
Later, hot rolled strip volume is cold-rolled to 0.75mm, carries out surface observation centered on end and investigates the production of crackle
Raw situation, using (determine A) the case where not cracking completely although, crack seldom, be practically without the feelings of problem
The case where condition (determine B~judgement C), severe crack, (determining D) this 4 ranks had rated the degree of the crackle.
Then, after being annealed in argon atmosphere with 650 DEG C × 5 hours conditions, cold formability has been investigated.It is cold
Formability test is carried out by cupping test (according to JIS Z 2247).
These evaluation results are shown in Table 3 below together.
Table 1
Table 2
Table 3
As shown in Table 1 to Table 3, for the titanium plate base before melt surface 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 go from surface towards inside and reduce
Oxygen concentration gradient.
In addition, in each example of the present invention, Cd(=C1- C2) it is 0.15mass% or less.In addition, at for melt surface
Titanium plate base (titanium material for hot rolling) after reason plays d from surface in each example of the present invention1Position until (i.e. remelted solidification
Layer play bottom from surface until) part oxygen concentration constant, oxygen concentration of the oxygen concentration relative to base material part
C0Increment Delta CmIt is 0.1mass% or less.
Also, it in these examples of the present invention, confirms, is not cracked in the cold rolling of the roll bending after hot rolling and pickling
(determining A), although or producing crackle few (determining B~judgement C), being practically without obstruction.In addition, being moved back for cold rolling-
Cold formability after fire has also obtained the Erichsen number of 11.5mm or more, and it is good for confirming it.Especially, in the 2nd technical solution
Middle restriction, Cd(=C1- C2) value be 0.1mass% No.3 below, 6,11,12 in, do not generate when cold rolling crackle (determine
A), the high level of 12mm or more is also shown in Erichsen number.
On the other hand, in the No.7 as comparative example, Cd(=C1- C2) it has been more than 0.15mass%.In addition, for table
Titanium plate base (titanium material for hot rolling) after the melt process of face plays d from surface in each comparative example1Position until (melt again
Melt solidification layer play bottom from surface until) the oxygen concentration of part be constant in the same manner as each example of the present invention, but should
Average oxygen concentration C of the oxygen concentration relative to base material part0Increment Delta CmIt has been more than 0.1mass%.
Also, in the comparative example, confirm, although not cracked in cold rolling, after cold rolling-annealing it is cold at
Shape is poor (Erichsen number is 11mm or less).
Test example 2
Using the pure titanium of ASTM grade 2 as melting raw material, carried out using equipment as shown in Figure 1 by electron-beam smelting
DC casting, having obtained section is about 1100mm wide × about 220mm thickness × about 7000mm long titanium plate base.Average casting speed
Degree is 1.9ton/h.
In melting and casting, in order to inhibit the oxygen of superficial layer of a part of slab (No.13~No.18 of table 4) dense
Degree, applies the countermeasure of any one in the countermeasure A~countermeasure C or more.For a part slab (No.19 of table 4),
The countermeasure for inhibiting the oxygen concentration of superficial layer is not carried out.
In addition, for the DC slab manufactured with condition identical with No.19, in the advance of next melt surface processing
It has gone surface cutting (cutting depth is 0.5mm~2.5mm), the slab of No.20~No.24 of table 5 is made.
Later, slab is continuously moved on one side, is irradiated on one side using electron beam and wider two faces of slab is carried out
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
The electron beam of 2.5cm keeps other electron beam irradiation conditions (slab movement speed when the output power of electron beam, irradiation, every
The heat input etc. of 1cm) variation, make fusion penetration (depth of remelted solidification layer) d away from surface location of slab1Variation.
In above process, for the wider face of each titanium plate base before melt surface processing, in the same manner as test example 1,
Using for section EPMA analysis (X-ray microanalysis instrument) to the oxygen concentration of the superficial layer in the face and its distribution quantitatively into
Investigation is gone.
In addition, being adjusted for the example (No.21~No.24) for having carried out surface cutting before carrying out melt surface processing
Each oxygen concentration after having looked into cutting.
By the oxygen concentration and its point of superficial layer related with each slab No.13~No.24 before the processing of these melt surfaces
The investigation result of cloth indicates in table 4 and table 5.
On the other hand, for melt surface treated each titanium plate base (for titanium material for hot rolling；Carrying out surface cutting
In the case where for the blank after the cutting) wider face, investigated the oxygen concentration C on surfacemax, the averaged oxygen of base material part it is dense
Spend C0, d is played to from surface1Position until (i.e. remelted solidification layer play bottom from surface until) part oxygen it is dense
Average oxygen concentration C spend, relative to base material part0Increment Delta CmIt is investigated.It the results are shown in table 6.
Also, titanium material for hot rolling after the completion of by melt surface processing obtained as described above is inserted into 800 DEG C
Furnace in after, carry out about 240 minutes heat, with continuously hot rolling band and strip rolling mill manufacture 5mm thickness hot rolled strip roll up, across wrap
Containing nitric acid-hydrofluoric acid continuous acid-washing production line, every one side dissolution has pruned about 40 μm.
Later, hot rolled strip volume is cold-rolled to 1.2mm, carries out surface observation centered on end and investigates the generation of crackle
Situation, the evaluation for crackle are determined in the same manner as test example 1 using 4 ranks (determining A~judgement D).It 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 before melt surface processing, confirm, each example of the present invention (No.14,
15, it 17,18,21~24) and in comparative example (No.13,16,19,20), all has 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 0.15mass% or less.In addition, at for melt surface
Titanium plate base (titanium material for hot rolling) after reason plays d from surface in each example of the present invention1Position until (i.e. remelted solidification
Layer play bottom from surface until) part oxygen concentration constant, oxygen concentration of the oxygen concentration relative to base material part
C0Increment Delta CmIt is 0.1mass% or less.
Also, it in these examples of the present invention, confirms, is not cracked in the cold rolling of the roll bending after hot rolling and pickling
(determining A), although or producing crackle few (determining B~judgement C), being practically without obstruction.Especially, in the 2nd technology
Limited in scheme, Cd(=C1- C2) value be 0.10mass% No.18 below, 22,23,24 in, splitting when not generating cold rolling
Line (determines A), has high cold-rolling property.
On the other hand, as comparative example No.19, in 20, Cd(=C1- C2) it has been more than 0.15mass%.In addition,
As the No.13 of comparative example, in 19, C1It has been more than 0.2mass%, similarly, in No.13,16,19 as comparative example, C2
It has been more than 0.05mass%.
In these each comparative examples, for melt surface treated titanium plate base (titanium material for hot rolling), played from surface
d1Position until (i.e. remelted solidification layer play bottom from surface until) part oxygen concentration and each example of the present invention it is same
It is sample constant, but average oxygen concentration C of the oxygen concentration relative to base material part0Increment Delta CmIt is more than
0.1mass%.
Also, in these comparative examples, confirm, produced in cold rolling significant crackle (determining D), cold-workability compared with
Difference.
More than, the preferred embodiment of the present invention, embodiment are illustrated, 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, so that it may right
Composition is added, omits, replacing and other changes.I.e. the present invention is not limited to above-mentioned explanations, simply by accompanying
The range of claims be defined, and suitable change can be carried out in the range.
Description of symbols
10, titanium plate base；12, electron beam irradiates rifle；16, melt surface process layer；d1, melt surface process layer depth；
R1, the 1st region；R1, the 2nd region.
Claims (8)
1. a kind of melt surface processing titanium plate base is to form depth d on the surface of titanium plate base using melt surface processing1
Remelted solidification layer and by being used when manufacturing titanium as the hot rolling of rolling surface using the surface, wherein
The titanium plate base is as made from the DC slab casting method under vacuum or inert gas atmosphere, maintains as-cast condition
Titanium plate base,
On the thickness direction of the titanium plate base, d will be played from the surface1Region until/2 position is set as the 1st region,
It will be from the d1Play the d in/2 position1Position until region be set as the 2nd region, by being averaged in the 1st region
Oxygen concentration is set as C relative to the increment of the average oxygen concentration of the base material of the titanium plate base1, by the averaged oxygen in the 2nd region
Concentration is set as C relative to the increment of the average oxygen concentration of the base material of the titanium plate base2, by C1With C2Between poor C1- C2It is set as
Cd, at this point,
C1For 0.20mass% hereinafter, C2For 0.05mass% hereinafter, and CdIt greater than 0 and is 0.15mass% or less.
2. melt surface processing titanium plate base according to claim 1, wherein
The CdFor 0.10mass% or less.
3. melt surface processing titanium plate base according to claim 1 or 2, wherein
The d1In the range of 3.0mm~10.0mm.
4. melt surface processing titanium plate base according to claim 1 or 2, wherein
After eliminating the surface with 3.0mm thickness cutting below, implement melt surface processing.
5. melt surface processing titanium plate base according to claim 3, wherein
After eliminating the surface with 3.0mm thickness cutting below, implement melt surface processing.
6. a kind of titanium material for hot rolling, wherein
The titanium material for hot rolling is the table in the titanium plate base using melt surface processing described in any one of claims 1 to 5
Face forms depth d1Remelted solidification layer and by being used when manufacturing titanium as the hot rolling of rolling surface using the surface.
7. titanium material for hot rolling according to claim 6, wherein
Oxygen concentration on thickness direction is distributed in the boundary position between the remelted solidification layer and base material from base material towards table
Face is in step-like increase.
8. titanium material for hot rolling according to claim 7, wherein
The increment of average oxygen concentration of the average oxygen concentration of the remelted solidification layer relative to the base material be 0.1mass% with
Under.
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| JP6698230B1 (en) * | 2018-06-27 | 2020-05-27 | 東邦チタニウム株式会社 | Method for producing titanium material for hot rolling, and method for producing hot rolled material |
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| CN1067397A (en) * | 1991-06-05 | 1992-12-30 | 通用电气公司 | Method and apparatus with the metal material of ingot form casting electron beam melting |
| JP2007332420A (en) * | 2006-06-15 | 2007-12-27 | Nippon Steel Corp | Method for producing titanium material and stock for hot rolling |
| CN102307682A (en) * | 2009-02-09 | 2012-01-04 | 新日本制铁株式会社 | Titanium material for hot rolling and manufacturing method thereof |
| CN103459063A (en) * | 2011-04-22 | 2013-12-18 | 新日铁住金株式会社 | Titanium slab for hot rolling and process for producing same |
| WO2014163089A1 (en) * | 2013-04-01 | 2014-10-09 | 新日鐵住金株式会社 | Titanium slab for hot rolling and method for manufacturing same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS63165047A (en) * | 1986-12-25 | 1988-07-08 | Kobe Steel Ltd | Continuous melting and casting method by electron beam |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1067397A (en) * | 1991-06-05 | 1992-12-30 | 通用电气公司 | Method and apparatus with the metal material of ingot form casting electron beam melting |
| JP2007332420A (en) * | 2006-06-15 | 2007-12-27 | Nippon Steel Corp | Method for producing titanium material and stock for hot rolling |
| CN102307682A (en) * | 2009-02-09 | 2012-01-04 | 新日本制铁株式会社 | Titanium material for hot rolling and manufacturing method thereof |
| CN103459063A (en) * | 2011-04-22 | 2013-12-18 | 新日铁住金株式会社 | Titanium slab for hot rolling and process for producing same |
| WO2014163089A1 (en) * | 2013-04-01 | 2014-10-09 | 新日鐵住金株式会社 | Titanium slab for hot rolling and method for manufacturing same |
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