CN107541681A - The ferrite-group stainless steel of the excellent in low temperature toughness of welding point - Google Patents
The ferrite-group stainless steel of the excellent in low temperature toughness of welding point Download PDFInfo
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- CN107541681A CN107541681A CN201710120948.4A CN201710120948A CN107541681A CN 107541681 A CN107541681 A CN 107541681A CN 201710120948 A CN201710120948 A CN 201710120948A CN 107541681 A CN107541681 A CN 107541681A
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- stainless steel
- welding point
- ferrite
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Classifications
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- 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
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3053—Fe as the principal constituent
- B23K35/308—Fe as the principal constituent with Cr as next major constituent
- B23K35/3086—Fe as the principal constituent with Cr as next major constituent containing Ni or Mn
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Nonmetallic Welding Materials (AREA)
Abstract
The present invention discloses a kind of ferrite-group stainless steel of welding point excellent in low temperature toughness.Ferrite-group stainless steel according to an embodiment of the invention, in terms of weight %, including：Cr：9~30%, N：Less than 0.015%, Al：0.005~0.04%, Ti：0.1~0.5%, surplus Fe and other inevitable impurity, and meet with following formula (1), and including maximum gauge be 0.05 to 5 μm, there is 9/mm2The Al Ca Ti Mg O systems oxide of distribution density above.Therefore, it is possible to control the size and distribution density of Al Ca Ti Mg O systems oxide in the mother metal of stainless steel, thus, it is possible to fully refine welding point solidified structure, so as to improve the mouldability of ferrite-group stainless steel and welding point low-temperature flexibility, Ti>(0.0065Cr+0.38N+8.3Al) formula (1).
Description
Technical field
The present invention relates to a kind of ferrite-group stainless steel, more specifically, it is excellent to be related to a kind of low-temperature flexibility of welding point
Different ferrite-group stainless steel.
Background technology
Ferrite-group stainless steel is mainly used in automobile exhaust system accessory, is mainly molded and welds institute by punch process
Processed goods is stated, or final products are made by carrying out expander and shaping to soldered conduit.Therefore, automobile exhaust system
It is, for example, welding point processing characteristics with the important requirement condition of ferrite-group stainless steel.
Typically, the welding process of ferrite-group stainless steel is to utilize electric arc thermal melting mother metal, and the metal now melted is quick
Cool down and form solidified structure, the grain size of this solidified structure and the processability of shape Welded Joints have a great impact.
Especially, because the heat input of the welding method for automobile exhaust system is big, scope is wide, the crystal grain of welding point
Coarsening, the probability increase for causing to be cracked during post-processing.Moreover, the coarsening of welding point crystal grain, which has, hinders
The feature of low-temperature flexibility characteristic, especially, in the winter time during converted products, welding point cracking frequency sharply increases.
Therefore, could be aware that, in order to meet the welded joint performance of automobile exhaust system accessory, it is necessary to refined molten joint
Solidified structure.
Current solidified structure refinement technology has low temperature casting process and electromagnetic agitation (Electro Magnetic
Stirring) method etc., although however, this technology can refine the solidified structure of mother metal, connect for melting during welding
The refinement of the solidified structure of head does not have effect but.
Especially, the curing condition of welding point cooling velocity compared with general curing condition is fast, is easily grown to column branch
Crystalline substance, therefore, there is the feature of solidified structure coarsening.Therefore, can be non-by encouraging in order to refine welding point solidified structure
Homogeneous nucleation passes through the oxide remained when the melting joint melted again during welding solidifies again to realize, occur it is heterogeneous into
Core, so as to promote the nucleation of equiax crystal and growth, prediction solidified structure will refine.
It is public in existing literature 1 as an example of the nonhomogen-ous nucleation of the oxide using ferrite-group stainless steel
The technology using Al-Mg systems field trash refinement mother metal tissue has been opened, has been disclosed in existing literature 2 with including the compound of Ti and Ca
Oxide is the technology that main system makes stainless steel.Can be by generating MgO, MgO-Al in addition, being disclosed in existing literature 32O3
Ensure mother metal tissue.
However, the refinement that focuses on mother metal solidified structure of the described existing literature 1 to existing literature 3, and for weldering
The composition of the oxide of joint solidified structure or the size of oxide, quantity do not consider.Especially, with regard to welding point and
Speech, because differently, melting temperature is high with general cast sturcture, it is thus possible to effect is lost because of melting again for oxide, and
And because cooling velocity is fast, therefore with the feature for the size for needing to control the oxide for refining.Therefore, it is just described special
For sharp document, the method for optimizing of the solidified structure refinement of welding point is not used to.
Prior art literature
【Patent document】
(existing literature 1) Korean Patent Laid the 10-2011-0074217th (on June 30th, 2011 is open)
(existing literature 2) Japanese Laid-Open Patent Publication the 2000-001715th (on January 7th, 2000 is open)
(existing literature 3) Japanese Laid-Open Patent Publication the 2001-254153rd (disclosure on the 18th of September in 2001)
The content of the invention
(1) technical problems to be solved
The purpose of embodiments of the invention is to provide a kind of can be coagulated by the mother metal tissue and welding point of stainless steel
Gu tissue is refined to improve the ferrite-group stainless steel of the low-temperature flexibility of the mouldability of stainless steel and welding point.
(2) technical scheme
The ferrite-group stainless steel of welding point excellent in low temperature toughness according to an embodiment of the invention, with weight %
Meter, including：Cr：9~30%, N：Less than 0.015%, Al：0.005~0.04%, Ti：0.1~0.5%, surplus Fe and its
His inevitable impurity, and meeting with following formula (1), and including maximum gauge be 0.05 to 5 μm, have 9/more than mm2's
The Al-Ca-Ti-Mg-O systems oxide of distribution density.
Ti>(0.0065Cr+0.38N+8.3Al) --- --- formula (1)
Also, according to one embodiment of present invention, it can include：C：Less than 0.02%, Si：0.01~0.5%, Mn：
0.01~0.5%, S：Less than 0.01%, P：Less than 0.04%, Ca：0.0001~0.003%.
Also, according to one embodiment of present invention, it can include being selected from by Mo：0.1~2.0%, Ni：0.1~2.0%
And Cu：One or more of group of 0.1~2.0% composition.
Also, according to one embodiment of present invention, Al-Ca-Ti-Mg-O systems oxide meets with following formula (2),
% (TiO2)+% (CaO) >=40------ formulas (2).
Also, according to one embodiment of present invention, Al-Ca-Ti-Mg-O systems oxide meets with following formula (3) extremely
(5),
% (TiO2)+% (CaO)+% (Al2O3) >=80------ formulas (3)
(% (TiO2)+% (CaO))/(% (TiO2)+% (CaO)+% (Al2O3)) >=0.4------ formulas (4)
0.3≤% (CaO)/% (TiO2)≤0.8------ formulas (5).
Also, according to one embodiment of present invention, the average grain diameter of welding point solidified structure is less than 90 μm.
Also, according to one embodiment of present invention, welding point ductile-brittle transition temperature (DBTT) be -65 DEG C with
Under.
(3) beneficial effect
Embodiments of the invention can be controlled in the mother metal of stainless steel by controlling the components system of ferrite-group stainless steel
The size and distribution density of Al-Ca-Ti-Mg-O systems oxide, and thus, it is possible to fully refine welding point solidified structure, so as to
The mouldability of ferrite-group stainless steel and the low-temperature flexibility of welding point can be improved.
Brief description of the drawings
Fig. 1 is the photo of the welding point solidified structure for the ferrite-group stainless steel for showing one embodiment of the present of invention.
Fig. 2 is the photo of the welding point solidified structure for the ferrite-group stainless steel for showing comparative example.
Fig. 3 is in the crystal grain of welding point solidified structure for the ferrite-group stainless steel for showing one embodiment of the present of invention
The chart of the composition analysis result of the nucleation field trash of center portion.
Fig. 4 is the average crystalline substance of the welding point solidified structure for the ferrite-group stainless steel for showing one embodiment of the present of invention
The chart of grain size measurement result.
Fig. 5 is the putting down based on welding point solidified structure for the ferrite-group stainless steel for showing one embodiment of the present of invention
% (CaO+TiO in the average constituent of the oxide of equal grain size2) measurement result chart.
Fig. 6 is the measure knot of the welding point impact energy for the ferrite-group stainless steel for showing one embodiment of the present of invention
The chart of fruit.
Fig. 7 is the welding point ductile-brittle transition temperature for the ferrite-group stainless steel for showing one embodiment of the present of invention
Spend the chart of the measurement result of (DBTT).
Embodiment
Below, embodiments of the invention are described in detail referring to the drawings.The following examples are in order to the present invention
Person of an ordinary skill in the technical field fully passs on the thought of the present invention and proposed.The present invention is not limited to refer to herein
Embodiment, can embody otherwise.In order to clearly state the present invention, the portion unrelated with explanation is eliminated in figure
Point, and in order to make it easy to understand, can more or less enlarged representation inscape size.
The ferrite-group stainless steel of the excellent in low temperature toughness of the welding point of one embodiment of the present of invention, with weight %
Meter, including：Cr：9~30%, C：Less than 0.02%, N：Less than 0.015%, Al：0.005~0.04%, Si：0.01~
0.5%th, Mn：0.01~0.5%, S：Less than 0.01%, P：Less than 0.04%, Ca：0.0001~0.003%, Ti：0.1~
0.5%th, surplus Fe and other inevitable impurity.
Cr content is 9~30%.When Cr content be less than 9% when, the corrosion resistance as stainless steel is insufficient, when more than
When 30%, mouldability reduces, and therefore, its content range is preferably 9~30%.
C content is less than 0.02%.C is interstitial element, when addition increase, with the reduction of elongation percentage, shaping
When processability reduce, therefore by maximum constraint be 0.02%.Preferably, it is contemplated that the cost during steelmaking operations, will contain
0.002% is defined under amount.Therefore, its content range is preferably 0.002~0.02%.
N content is less than 0.015%.N is interstitial element, when addition increase, with the reduction of elongation percentage, shaping
When processability reduce, therefore by maximum constraint be 0.015%.Preferably, it is contemplated that the expense during steelmaking operations, will contain
0.002% is defined under amount.Therefore, its content range is preferably 0.002~0.015%.
Al content is 0.005~0.04%.Al is necessary element, still, when a large amount of additions as deoxidant element
When, due to forming invalid oxide, the coarsening of uncontrollable welding point crystal grain, therefore, it is difficult to improve low-temperature flexibility.Cause
This, it is contemplated that deoxidation effect, including at least more than 0.005%, and for the refinement of welding point crystal grain, by maximum constraint
For 0.04%.Therefore, its content range is preferably 0.005~0.04%.
Si content is 0.01~0.5%.Si is from the aspect of corrosion proof and the element that adds, when less than 0.01%
When, it is difficult to sufficient corrosion resistance is obtained, however, when more than 0.5%, the impurity increase of material, causes elongation percentage and processing hard
Changing index (n values) reduces, and Si systems field trash increase, processability is deteriorated.Therefore, its content range is preferably 0.01~0.5%.
Mn content is 0.01~0.5%.Mn is from the aspect of corrosion resistance and the element of addition, when less than 0.01%
When, it is difficult to sufficient corrosion resistance is obtained, however, when more than 0.5%, the impurity increase of material, causes elongation percentage and corrosion resistance
Reduce.Therefore, its content range is preferably 0.01~0.5%.
S content is less than 0.01%.From the aspect of corrosion proof, S content is preferably low content.Preferably, examine
Consider the cost during steelmaking operations, 0.0001% will be defined under content.Therefore, its content range is preferably 0.0001
~0.01%.
P content is less than 0.04%.From the aspect of corrosion resistance, P content is preferably low content.Preferably, consider
Cost during to steelmaking operations, 0.0001% will be defined under content.Therefore, its content range be preferably 0.0001~
0.04%.
Ca content is 0.0001~0.003%.Ca is the weight to form the effective oxide of the present invention as deoxidant element
Element is wanted, however, when a large amount of include, suppresses the formation of effective oxide, and is also unfavorable for corrosion resistance, therefore, by maximum
Value is set to 0.003%, and minimum value is set into the minimum value for forming effective oxide, i.e., 0.0001%.Therefore, its content model
Enclose preferably 0.0001~0.003%.
Ti content is 0.1~0.5%.For Ti, preferentially with C, N with reference to and formed suppress corrosion resistance reduce precipitation
Thing, however, when Ti content is less than 0.1%, it is unable to reach the Al-Ca-Ti-Mg-O systems oxide as the purpose of the present invention
Component, size and distribution density, when Ti content is more than 0.5%, because of such as TiN etc. high-melting-point nitride, finally producing
The linear discontinuities as caused by field trash occur in product, when manufacturing continuous casting billet, spray nozzle clogging, processability reduce.
It is the most important element for determining the effective oxide of the present invention for Ti, can by a series of experiment
Determine the component and the minimum Ti contents of size and distribution density for meeting the effective oxide in the present invention described later.This hair
Bright middle considered Ti minimum value, by meeting that Cr contents in the range of the component and N content and Al content are influenceed,
And it should meet with following formula (1).
Ti>(0.0065Cr+0.38N+8.3Al) --- --- formula (1)
When being unsatisfactory for the formula (1), component, size and the distribution of the oxide as the purpose of the present invention are unable to reach
Density.That is, the average grain diameter with the solidified structure of the stainless steel welded joint for the scope for departing from the formula (1) exceedes
100 μm, ductile-brittle transition temperature (DBTT) causes low-temperature flexibility to reduce more than -65 DEG C.
Also, the ferrite-group stainless steel of the excellent in low temperature toughness of the welding point of one embodiment of the present of invention, with weight
% meters are measured, including selected from by Mo：0.1~2.0%, Ni：0.1~2.0% and Cu：In the group of 0.1~2.0% composition it is a kind of with
On.
Mo content is 0.1~2.0%.Mo is the corrosion proof constituent for increasing stainless steel, can additionally be added,
When being excessively added, impact characteristics can be reduced, increase the danger being broken during processing, and material cost increases, therefore,
In view of the problem, Mo constituent ratio is preferably limited to 0.1 to 2.0% in the present invention.
Ni content is 0.1~2.0%.Ni is to improve corrosion proof element, and when a large amount of additions, not only hardening, goes back
There is the worry that SCC occurs, it is therefore preferable that being less than 2.0%.
Cu content is 0.1~2.0%.In order to improve corrosion resistance, Cu is preferably included below 0.1~1.0 weight %.So
And when more than 1.0 weight %, processability reduces.
Ferrite-group stainless steel can will meet the stainless steel of the components system through electric furnace (EAF), refining furnace (AOD), group
Point adjustment (LT), tundish (Tundish), continuous casting process and after manufacturing steel billet, hot rolled, annealing, cold rolling, annealing are made cold
Roll roll bending (coil).
Fig. 1 is the photo of the welding point solidified structure for the ferrite-group stainless steel for showing one embodiment of the present of invention.
Fig. 2 is the photo of the welding point solidified structure for the ferrite-group stainless steel for showing comparative example.Fig. 3 is show the present invention one
The component analysis knot of the nucleation field trash of the crystal grain central part of the welding point solidified structure of the ferrite-group stainless steel of embodiment
The chart of fruit.
Referring to figs. 1 to Fig. 3, the reason in order to confirm the solidified structure difference in welding point region, electron microscope is utilized
The nucleation field trash of precision observation equiax crystal central part, its result are observed such as the spherical oxide of embodiment or oxidation in Fig. 3
Thing and the TiN around the oxide, the oxidation can be seen that by the accurate observation spherical oxide of transmission electron microscope
Thing is with the CaO-TiO of crystalline2Phase and amorphous Al2O3The form of-MgO phases is present.In contrast to this, in a comparative example,
Although it has been confirmed that spherical oxide be present in the absence of oxide or in TiN, most of oxide is with Al2O3-MgO
The form of phase is present.Therefore, from the result it has been confirmed that as the solidified structure of welding point equiax crystal or TiN into
Epipole (site), CaO-TiO2Compared to advantageous.
According to an embodiment of the invention, Al-Ca-Ti-Mg-O systems are included for refining the scheme of welding point solidified structure
Oxide, the oxide will not be also melted in molten steel again in high sweating heat, and is remained with solid phase, when melting for welding point
When melting metal freezing, using the teaching of the invention it is possible to provide Delta (δ)-ferritic effective nucleating point.Also, confirm in order that the oxidation
Thing fully refines the solidified structure of welding point, therefore, to assure that its size and distribution density.
Therefore, the ferrite-group stainless steel of the excellent in low temperature toughness of the welding point of one embodiment of the present of invention is included most
Major diameter is 0.05 to 5 μm, has 9/mm2The Al-Ca-Ti-Mg-O systems oxide of distribution density above.
When the maximum gauge of the Al-Ca-Ti-Mg-O systems oxide included by the ferrite-group stainless steel is less than
At 0.05 μm, oxide is too small, can not play a part of Delta (δ)-ferritic effectively nucleating point, when more than 5 μm, promote
Enter flotation, its residual quantitative change is few, can not play the sufficient effect as nucleating point, causes the crystalline substance of welding point solidified structure
Grain average diameter is more than 90 μm.
When the Al-Ca-Ti-Mg-O systems oxide that the ferrite-group stainless steel includes distribution density be less than 9/
mm2When, sufficient Delta (δ)-ferritic effective nucleating point can not be provided, cause subsequent welding point solidified structure
Average grain diameter is more than 90 μm, and thus, ductile-brittle transition temperature (DBTT) reduces low-temperature flexibility more than -65 DEG C.
For example, Al-Ca-Ti-Mg-O systems oxide includes TiO2、CaO、Al2O3, MgO etc., now, the Al-Ca-
Ti-Mg-O systems oxide meets with following formula (2).
% (TiO2)+% (CaO) >=40------ formulas (2)
When meeting the Ti minimum values of the formula (1), the formula (2) will be met, when the Ti of the formula (1) can not be met most
During small value, the formula (2) can not be met.That is, controlled by the condition of the Cr contents based on the formula (1), N content and Al content
Ti values, so as to % (TiO in Al-Ca-Ti-Mg-O systems oxide2) and % (CaO) and can be more than 40%.Thus,
By largely ensuring to be used as the equiax crystal of welding point solidified structure or the TiN favourable CaO-TiN of nucleating point2Phase, Neng Gouxi
Change the average grain diameter of welding point solidified structure, improve low-temperature flexibility.
For example, Al-Ca-Ti-Mg-O systems oxide meets with following formula (3) to (5).
% (TiO2)+% (CaO)+% (Al2O3) >=80------ formulas (3)
(% (TiO2)+% (CaO))/(% (TiO2)+% (CaO)+% (Al2O3)) >=0.4------ formulas (4)
0.3≤% (CaO)/% (TiO2)≤0.8------ formulas (5)
According to the formula (3), field trash during Al deoxidations is Al-Ca-Ti-Mg-O systems, wherein % (TiO2), % (CaO)
With % (Al2O3) overall ratio should be more than 80%.As % (TiO2), % (CaO) and % (Al2O3) overall ratio be less than 80%
When, stabilized is rich magnesium (MgO rich) oxide or Al2O3- MgO systems oxide, it can not be formed to being nucleated effective CaO-
TiO2Phase.
According to the formula (4), the % (TiO relative to formula (2) and formula (3) are set2) and % (CaO) overall ratio %
(TiO2), % (CaO) and % (Al2O3) overall ratio, in order to further largely ensure the equiax crystal as welding point solidified structure
Or the TiN favourable CaO-TiO of nucleating point2Phase, when its ratio is less than 0.4, CaO-TiO2The ratio of phase is reduced, it is difficult to fully
Refine the average grain diameter of welding point solidified structure.
According to the formula (5), even if meeting the formula (3) and formula (4), as % (CaO)/% (TiO2) ratio be less than 0.3
When, the constituent of oxide can not be substantially ensured that to being nucleated favourable CaO-TiO2, as % (CaO)/% (TiO2) ratio exceedes
When 0.8, oxide constituent translates into CaO-Al2O3Thick low melting point oxide, so as to translate into be nucleated it is invalid
Oxide.
That is, the ferrite-group stainless steel of one embodiment of the present of invention meets the formula (2) to formula (5), and including maximum
A diameter of 0.05 to 5 μm, there is 9/mm2The Al-Ca-Ti-Mg-O systems oxide of distribution density above.
Fig. 4 is the average crystalline substance of the welding point solidified structure for the ferrite-group stainless steel for showing one embodiment of the present of invention
The chart of the measurement result of grain size.Fig. 5 be show one embodiment of the present of invention ferrite-group stainless steel based on welding
% (CaO+TiO in the average constituent of the oxide of the average crystal grain size of joint solidified structure2) measurement result figure
Table.
Reference picture 4, it is the solidification for the ferrite-group stainless steel welding point for determining examples and comparative examples of the present invention
Organize the chart of the average diameter of crystal grain.That is, the result of the equiax crystal size of the welding point of comparing embodiment and comparative example, energy
Enough confirm embodiment compared to comparative example, equiax crystal size refinement about 40% or so.Specifically, it can be seen that embodiment
The average grain diameter of the welding point solidified structure of ferrite-group stainless steel is less than 90 μm.However, it is possible to find out, comparative example
Ferrite-group stainless steel welding point solidified structure average grain diameter more than 90 μm, specifically more than 100 μm.
That is, the crystal grain of the welding point solidified structure of the ferrite-group stainless steel of one embodiment of the present of invention is averaged
Diameter can be less than 90 μm.
Reference picture 5, it is to utilize SEM-power spectrum (SEM-EDS) analytical equipment measure embodiments of the invention
With the % (CaO+TiO in the average constituent of the oxide of the ferrite-group stainless steel of comparative example2) chart.
That is, Welded Joints grain size and the constituent of oxide, especially Welded Joints grain size and conduct
CaO-TiO2The CaO phases and TiO in the source (source) of phase2The dependency relation of phase sum is investigated, and its result can be seen that
As % (CaO+TiO2) be more than 40% when, it can be ensured that welding point grain size be less than 90 μm, so as to realize carefully
Change, as % (CaO+TiO2) be less than 40% when, welding point coarse grains.
Fig. 6 is the measure knot of the welding point impact energy for the ferrite-group stainless steel for showing one embodiment of the present of invention
The chart of fruit.Fig. 7 is the ductile-brittle transition of the welding point for the ferrite-group stainless steel for showing one embodiment of the present of invention
The chart of the measurement result of temperature (DBTT).
Reference picture 6, it is the chart for comparing implementation column and the welding point impact energy of comparative example.It can be calculated and prolonged by chart
Property-brittle transition temperature (DBTT), the temperature of embodiment are cited as -74 DEG C, and the temperature of comparative example is cited as -54 DEG C.That is, with every
On the basis of individual DBTT, destruction becomes brittle break from ductile fracture, and this sends out when being and processing welding point under cryogenic
The main reason for raw crackle.Therefore, DBTT is preferably low temperature.
Reference picture 7, it is the ductile-brittle of the welding point of the ferrite-group stainless steel of examples and comparative examples of the present invention
The measure figure of transition temperature (DBTT).I.e., it is possible to find out, embodiment is compared to about low 20 DEG C or so of comparative example its DBTT.
That is, the DBTT of the ferrite-group stainless steel welding point of one embodiment of the present of invention can be less than -65 DEG C.
Below, by embodiment, further the present invention is described in detail.
Embodiment 1 to 12
By the stainless steel of the mother metal components system of the embodiment 1 to 12 including table 1 below through electric furnace (EAF)-refining furnace
(AOD)-adjustment of formula (LT)-tundish (Tundish)-continuous casting process and after manufacturing steel billet, hot rolled and cold rolling manufacture is thick
Spend the steel plate for 1.2mm.
Comparative example 1 to 12
By the stainless steel of the mother metal components system of the comparative example 1 to 8 including table 1 below through electric furnace (EAF)-refining furnace (AOD)-
Adjustment of formula (LT)-tundish (Tundish)-continuous casting process and after manufacturing steel billet, hot rolled and cold rolling manufacture thickness is
1.2mm steel plate.
Table 1
Afterwards, in order to evaluate the welding characteristic of the steel plate according to the embodiment and comparative example manufacture, entered using GTA techniques
After row welding, grain size, welding point section and the surface analysis of welding point, hardness analysis are investigated, angstrom has stayed and to stretch
(ericessen) test, welding point impact energy etc..To as the molten steel composition of major influence factors and its subscale
Species and size distribution investigated, and represent in table 2 below and table 3.
Here, the species and size point of oxide are determined using SEM-power spectrum (SEM-EDS) analytical equipment
Cloth, analysis method is using horizontal 1mm, the longitudinal 1mm areas in the section to final products, under the multiplying power that more than 1000 times of amplification
The size of oxide and the mode of composition are automatically determined, is at least determined more than 5 regions, and represent its average value.The oxygen of measure
The maximum gauge of compound is 5 μm, and it is 1/mm to have most of more than the oxide quantity of the diameter2Hereinafter, and to nucleation
It is invalid, therefore, eliminated from calculating.
Table 2
Table 3
In order to by described embodiment come ensure the mouldability of the ferritic stainless steel of one embodiment of the present of invention and
Low-temperature flexibility, when disengaged (1), even if including components system, formula (2) and the quantity of oxide, therefore, Ke Yizhi can not be obtained
Dawn, crystal grain refinement and the low-temperature flexibility of welding point can not be ensured.
More specifically, moreover, mesh can be obtained by meeting the ferrite-group stainless steel of formula (3) to formula (5)
Oxide composition, size and distribution density are marked, therefore, could be aware that, can not ensure that the low temperature of crystal grain refinement and welding point is tough
Property.
As described above, the exemplary embodiment of the present invention is illustrated, but the present invention is not limited to this, technology belonging to the present invention
The those of ordinary skill in field can carry out a variety of changes it will be appreciated that in the case where not departing from the concept and scope of claims
More and deform.
Claims (7)
1. a kind of ferrite-group stainless steel of welding point excellent in low temperature toughness, in terms of weight %, including：Cr：9~30%, N：
Less than 0.015%, Al：0.005~0.04%, Ti：0.1~0.5%, surplus Fe and other inevitable impurity, and it is full
It is enough following formula (1), and including maximum gauge is 0.05 to 5 μm, there is 9/mm2The Al-Ca-Ti-Mg- of distribution density above
O systems oxide,
Ti>(0.0065Cr+0.38N+8.3Al) --- --- formula (1).
2. the ferrite-group stainless steel of welding point excellent in low temperature toughness according to claim 1, wherein, the stainless steel
Including：C：Less than 0.02%, Si：0.01~0.5%, Mn：0.01~0.5%, S：Less than 0.01%, P：Less than 0.04%, Ca：
0.0001~0.003%.
3. the ferrite-group stainless steel of welding point excellent in low temperature toughness according to claim 1, wherein, the stainless steel
Including selected from by Mo：0.1~2.0%, Ni：0.1~2.0% and Cu：One or more of group of 0.1~2.0% composition.
4. the ferrite-group stainless steel of welding point excellent in low temperature toughness according to any one of claim 1 to 3, its
In, Al-Ca-Ti-Mg-O systems oxide meets with following formula (2),
% (TiO2)+% (CaO) >=40------ formulas (2).
5. the ferrite-group stainless steel of welding point excellent in low temperature toughness according to any one of claim 1 to 3, its
In, Al-Ca-Ti-Mg-O systems oxide meets with following formula (3) to (5),
% (TiO2)+% (CaO)+% (Al2O3) >=80------ formulas (3)
(% (TiO2)+% (CaO))/(% (TiO2)+% (CaO)+% (Al2O3)) >=0.4------ formulas (4)
0.3≤% (CaO)/% (TiO2)≤0.8------ formulas (5).
6. the ferrite-group stainless steel of welding point excellent in low temperature toughness according to any one of claim 1 to 3, its
In, the average grain diameter of welding point solidified structure is less than 90 μm.
7. the ferrite-group stainless steel of welding point excellent in low temperature toughness according to any one of claim 1 to 3, its
In, welding point ductile-brittle transition temperature (DBTT) is less than -65 DEG C.
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| KR10-2016-0078714 | 2016-06-23 | ||
| KR1020160078714A KR101851245B1 (en) | 2016-06-23 | 2016-06-23 | Ferritic stainless steel having excellent low temperature toughness of welded joint |
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Cited By (2)
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|---|---|---|---|---|
| CN112654727A (en) * | 2018-08-03 | 2021-04-13 | 株式会社Posco | Ti-and nb-added ferritic stainless steel excellent in low-temperature toughness in weld parts |
| CN114318146A (en) * | 2021-12-24 | 2022-04-12 | 浦项(张家港)不锈钢股份有限公司 | High-toughness ferritic stainless steel and manufacturing method and application thereof |
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| WO1996023909A1 (en) * | 1995-02-03 | 1996-08-08 | Nippon Steel Corporation | High-strength line-pipe steel having low yield ratio and excellent low-temperature toughness |
| JP2000001758A (en) * | 1998-06-18 | 2000-01-07 | Kawasaki Steel Corp | Ferritic stainless steel good in surface property and excellent in corrosion resistance and forming workability |
| CN101381845A (en) * | 2007-09-04 | 2009-03-11 | 宝山钢铁股份有限公司 | High-purity ferrite stainless steel material and manufacturing method thereof |
| CN101845590A (en) * | 2009-03-25 | 2010-09-29 | 株式会社神户制钢所 | The steel of the good-toughness of welding heat affected zone |
| JP2012184494A (en) * | 2011-03-08 | 2012-09-27 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic stainless steel excellent in rusting resistance |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2001219291A (en) | 2000-02-09 | 2001-08-14 | Daido Steel Co Ltd | Weld zone of ferritic stainless steel and welding method |
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- 2016-06-23 KR KR1020160078714A patent/KR101851245B1/en active IP Right Grant
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| WO1996023909A1 (en) * | 1995-02-03 | 1996-08-08 | Nippon Steel Corporation | High-strength line-pipe steel having low yield ratio and excellent low-temperature toughness |
| JP2000001758A (en) * | 1998-06-18 | 2000-01-07 | Kawasaki Steel Corp | Ferritic stainless steel good in surface property and excellent in corrosion resistance and forming workability |
| CN101381845A (en) * | 2007-09-04 | 2009-03-11 | 宝山钢铁股份有限公司 | High-purity ferrite stainless steel material and manufacturing method thereof |
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| CN112654727A (en) * | 2018-08-03 | 2021-04-13 | 株式会社Posco | Ti-and nb-added ferritic stainless steel excellent in low-temperature toughness in weld parts |
| CN114318146A (en) * | 2021-12-24 | 2022-04-12 | 浦项(张家港)不锈钢股份有限公司 | High-toughness ferritic stainless steel and manufacturing method and application thereof |
Also Published As
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|---|---|
| KR20180000782A (en) | 2018-01-04 |
| CN107541681B (en) | 2019-07-02 |
| KR101851245B1 (en) | 2018-04-25 |
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