CN1918313A - Welded ferritic stainless steel tube having excellent tube expanding workability - Google Patents
Welded ferritic stainless steel tube having excellent tube expanding workability Download PDFInfo
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Abstract
A ferritic stainless steel pipe, which is producing by subjecting a raw material plate, which has a chemical composition, in mass %, that C: 0.001 to 0.015 %, N: 0.001 to 0.020 %, Cr: 11 to 25 %, Mo: 0.01 to 2.0 %, one or more of Ti and Nb: 0.05 to 0.5 %, B: 0.0003 to 0.0030 % and the balance: Fe and inevitable impurities, exhibits an elongation in the direction of the circumference as a raw material plate for a welded steel pipe of 30 % or more, and has an average r value of 1.5 or more, to forming, welding, correcting of 0.5 to 2.0 % in terms of a circumference, and optionally, annealing at a temperature of 700 to 850 DEG C, so as for the resulting pipe to have a difference of a weld zone and a base material zone in Vickers hardness of 10 to 40, a (a thickness of the bead in a weld zone/a thickness of a base material zone) of 1.05 to 1.3 and an elongation of the base material zone of a welded pipe in the circumference direction of 15 % or more.
Description
Technical field
The present invention relates to the expander processing of burning rail etc. of auto exhaust based part and automobile fuel based part strict and high temperature oxidation and adhere to corrosion that snow melting agent etc. causes and the employed welded ferritic stainless steel tube of purposes of high temperature salt damage seriously corroded, prevent to comprise 2 times or the mother metal of more eccentric processing and the expander processing crackle that near the mother metal welding zone or the welding zone takes place in parent tube footpath.
Background technology
Ferrite-group stainless steel because thermal expansivity is less, therefore is used to be subjected to repeatedly the auto exhaust based part of heating and cooling.And, recently lower in the stress corrosion cracking susceptibility of cold district when adhering to snow melting agent, so also begin to be applicable to the fuel filler pipe of automobile fuel based part.These parts majorities are welded tubes of thin-walled, and are subjected to bending machining, the protruding processing of distension and expander processing etc.The rail that acts as a fuel is especially opened the 2002-242779 communique points out as the spy, in order to seek rustless property, makes whole tubing and eccentric expander, imposes 2 times or the more processing in parent tube footpath sometimes, and the tubing that uses is required good expander.
In the face of these requirements, as the ferrite-group stainless steel pipe of excellent processability, to open as described in the flat 6-41689 communique as the spy, the regulation starting material are worth (r value) at the orchid gram Ford (lankford) of rolling direction and rolling vertical direction; It is described that and for example the spy opens flat 5-277769 communique, the preheating before the Laser Welding is proposed and eliminate in the unnecessary height of cap pass, depress the welding zone to eliminate the manufacture method of unnecessary height after probable; The spy opens flat 7-265941 communique, spy and opens flat 7-266072 communique, spy and open flat 7-286239 communique, spy and open flat 8-257777 communique and spy to open the 2000-326079 communique described for another example, the tubulation method and the laser welding of no rolling are combined, the roller radius of the tubulation method of the output rating of regulation laser welder and tubulation speed, no rolling and the relation and the rectification condition of thickness of slab, adjust the difference of hardness of mother metal district and welding zone, perhaps adjust C, N, O amount and the inclusion in laser welding district, improve the protruding processibility of distension, expander and the bendability of welding zone.But, only adjust the shape of raw-material material, welding bead and the hardness of welding bead, be difficult to bear 2 times of parent tube or more and follow the very strict expander processing of eccentric expander.
On the other hand, about starting material, the raising requirement etc. of weather resistance such as sternness, life-span because environment for use becomes, require the raising of solidity to corrosion, high temperature resistant salt damage, oxidation-resistance, hot strength and thermal fatigue, alloying element contents such as Cr, Mo, Nb have the trend of raising, but this is not preferred direction to processibility, so the welded tube starting material that the use properties of requirement and processibility have both.
Summary of the invention
The present invention proposes in view of such present situation, and its purpose is: be provided in the expander processing of eccentric processing of 2 times of comprising parent tube or more times and prevent expander processing crackle and near crackle that mother metal produced welding zone or the welding zone and the welded ferritic stainless steel tube that has excellent tube expanding workability that mother metal produces.
The present inventor is in order to reach above-mentioned purpose, the deformational behavior of the welded tube in the expander processing and the relation of expander and mother metal characteristic have been discussed, obtained following opinion: in order to make the expander raising undertaken by the multistage operation, to obtain comprising 2 times or more expander of the parent tube of eccentric expander operation, in the characteristic in the mother metal district behind characteristic that obtains material plate and tubulation, it is very important keeping the strength balance that hardness or bead thickness produced of mother metal and welding zone.Its main idea is as follows:
(1) a kind of welded ferritic stainless steel tube that has excellent tube expanding workability is characterized in that: for welded ferritic stainless steel tube, through be shaped, welding, correct after the unit elongation of the circumferential direction in welded tube mother metal district be 15% or more than.
(2) a kind of welded ferritic stainless steel tube that has excellent tube expanding workability is characterized in that: for a kind or 2 kinds welded ferritic stainless steel tube not containing with quality % score among 0.05～0.5% Ti, the Nb, the vickers hardness hv in the welding zone
WVickers hardness hv with mother metal
MDifference Δ the HV (=HV of hardness
W-HV
M) be 10～40 scope, the bead thickness T of welding zone
WWall thickness T with the mother metal district
MRatio RT (=T
W/ T
M) be 1.05～1.3.
(3) the described welded ferritic stainless steel tube that has excellent tube expanding workability in above-mentioned (1) or (2), it is characterized in that: it contains C:0.001～0.015% in quality %, Si:0.01～1.0%, Mn:0.01～1.0%, P:0.01～0.03%, S:0.0005～0.010%, N:0.001～0.020%, Cr:11～25%, Mo:0.01～2.0%, among Ti or the Nb a kind or 2 kinds each 0.05～0.5%, B:0.0003～0.0030%, surplus is made up of Fe and unavoidable impurities, and uses following material plate: the unit elongation of the direction of the circumferential direction that should become the welded tube material plate be 30% or more than, average Lankford value (r value) be 1.5 or more than.
(4) according to the manufacture method of any one described welded tube of (1)～(3), it is characterized in that: be shaped and welding after, impose and count 0.5～2.0% rectification by girth.
(5) according to the manufacture method of (4) described welded tube, it is characterized in that: after being shaped, welding, correcting, anneal in 700～850 ℃.
Description of drawings
Fig. 1 is the processing strain track of eccentric expander processing.
Fig. 2 is the crackle seen of eccentric expander district and the form of necking down.
Fig. 3 is the relation that necking down and crackle take place in the unit elongation of circumferential direction and the processing of eccentric expander.
Fig. 4 is the form of crackle in the expander processing.
Fig. 5 represents the vickers hardness hv of expander machining status and welding zone
WVickers hardness hv with the mother metal district
MDifference Δ the HV (=HV of hardness
W-HV
M) the bead thickness T of welding zone when being 10～40 scope
WWall thickness T with the mother metal district
MRatio RT (=T
W/ T
M) relation.
Fig. 6 represents the relation (SUS436L/TIG welded tube (φ 25.4mm * 0.8mmt)) of the difference Δ HV of hardness and the girth correct amount in the welding bead of welded tube and mother metal district.
Fig. 7 represents the difference Δ HV of hardness in the welding bead of welded tube and mother metal district and the relation of thermal treatment temp (SUS436L/TIG welded tube (φ 25.4mm * 0.8mmt)).
Embodiment
Below describe the present invention in detail.Usually, as shown in Figure 1, in the eccentric expander processing of the multistage operation of carrying out with punching, welded tube is at the stress of each operation by the tube axial direction that produced by the friction with drift, be compressed distortion and be subjected to tensile deformation at tube axial direction on one side at the pipe circumferential direction, by expander processed on one side.And in the occasion of following the processing of eccentric expander, eccentric district is protruding by distension, be subjected to the tensile deformation of direction of principal axis and circumferential direction partly, especially the strain of circumferential direction is tension strain and very big, therefore think that for eccentric expander is shaped, the unit elongation of guaranteeing circumferential direction is important.
In such processing, if the ductility deficiency in welded tube mother metal district is then shown in Figure 2, the distension protuberance in eccentric expander district produces along axial necking down and crackle.Such necking down and crackle for the fuel filler Guan Eryan of the automobile fuel based part of important safety control parts, are unallowed defectives.Relation to the ductility of the crackle in eccentric expander district and welded tube mother metal is studied, the result clearlys show: the crackle in eccentric expander district is relevant with the unit elongation of welded tube circumferential direction, as shown in Figure 3, in order to suppress necking down and crackle, the unit elongation of welded tube circumferential direction be 15% or more than be necessary, the unit elongation of circumferential direction is 10%～15% welded tube generation necking down, unit elongation be 10% or following welded tube crackle appears.And, in order to ensure the unit elongation of circumferential direction be 15% or more than, when being configured as open tubular, using as much as possible the method that is shaped with low strained and lower the tubulation strain, guarantee that the means of ductility etc. are necessary by the tubulation postheat treatment with roll forming and rolling formation.And, about the unit elongation of welded tube mother metal district, after circumferential direction cuts off and launches, cut the tensile test specimen parallel zone according to JIS13 B at circumferential direction, to carrying out tension test behind the two ends welding clamping part, measure breaking elongation.
About the welded tube material plate, for whole strain and local strain, in order to suppress the mother metal crackle and to suppress the expansion of crackle, the unit elongation that preferred use should become the direction of circumferential direction be 30% or above, average Lankford value be 1.5 or above ferrite-group stainless steel band.And their employed stainless steel plate material plates preferably use the high-purity ferritic stainless steel that has added Ti, Nb.
Under the inappropriate situation of strength balance in the welding zone of welded tube and mother metal district, crack.As shown in Figure 4, under the lower situation of the intensity of comparing the welding zone with the mother metal district, in welding zone generation direction of principal axis (vertically) crackle.On the other hand, in the too high occasion of intensity of comparing the welding zone with the mother metal district, the welding zone is littler than mother metal in the displacement of tube axial direction, become the protruding shape of distension in the pipe end welding zone in expander district, because welding zone and mother metal district are in the difference of the displacement of tube axial direction, shearing strain between the two increases, and cracks at tilted direction near the mother metal district the welding zone.And prerequisite is, because the local thickness that welding undercut and butt joint shape defect cause is thinner than the shape of welding zone at the position of mother metal, there is bad occasion as described above in the welding zone shape, cracks in direction of principal axis in the welding zone in order not exist in the welding zone.
In the past, the method that the strength balance in maintenance welding zone and mother metal district, conduct improve the processibility of welded tube, open flat 7-265941 communique etc. proposes as the spy, adjustment is created conditions so that the difference of mother metal hardness and welding zone hardness is 10～80, but the present inventor finds, in the expander processing of multistage, adjust the proper intensity balance that welding zone intensity (hardness) can not obtain welding zone and mother metal district only singlely, except welding zone hardness, it is necessary that the welding zone bead thickness is controlled at suitable scope.
And, for above-mentioned mother metal, in order to regulate welding zone hardness and bead thickness, when being shaped roll configuration and tooled joint passage roller (fin pass roll) at interval, extrusion roll at interval etc. molding condition and the correct amount and the heat-treat condition subsequently of being undertaken by the sizing (sizing) after being shaped be important.
Below, the concrete one-tenth of the welded tube that the present invention is used is grouped into and describes.
C, N:C, N make plasticity and solidity to corrosion deterioration when heavy addition, and for their fixing desired Ti amounts are increased, so their upper limit is, C is 0.015%, N is 0.020%.Consider the refining cost, their lower limit is that C, N all determine 0.001%.
Si:Si is the element that uses as deoxidant element, significantly reducing above 1.0% o'clock plasticity, so the upper limit is defined as 1.0%.In the occasion of considering the refining procedure cost, the 0.01%th, therefore the level of unavoidably sneaking into is defined as lower limit with it.
The occasion that Mn:Mn adds in volume, plasticity reduces, so the upper limit is defined as 1.0%.In the occasion of considering the refining procedure cost, the 0.01%th, therefore the level of unavoidably sneaking into is defined as lower limit with it.
P:P is because solution strengthening reduces plasticity, so the upper limit is defined as 0.03%.For lower limit, because selection raw material etc. increase steel-making cost, so lower limit is defined as 0.01%.
Because inclusion etc. makes the solidity to corrosion deterioration, so the upper limit is defined as 0.010% to S:S when heavy addition.Consider steel-making cost, lower limit is defined as 0.0005%.
Cr:Cr is in order to ensure as the necessary element of the solidity to corrosion of stainless fundamental characteristics.Needed Cr in the automobile fuel based part under the situation that forms coating, is limited to 11% down, and owing to make the cost of plasticity reduction or raising product or make the manufacturing deterioration, so its upper limit is defined as 25%.
Mo:Mo also is the element that stainless solidity to corrosion is improved.The upper limit is the same with Cr, considers to be defined as 2.0% from plasticity and cost aspect, and its lower limit is defined as 0.01% as inevitable level.
Ti, Nb: by add 0.05 quality % or above, be preferably add 0.1% or more than, combine with C, N, reduce C, the N of solid solution in steel, improve unit elongation and r value, can obtain making the effect of processibility raising.And make its stabilization by the carbide that makes C become Ti, Nb, suppress separating out of Cr carbide, can improve resistance to intergranular corrosion at welded heat affecting zone.On the other hand, add owing to solid solution superfluously and separate out the intensity that improves steel, perhaps add Ti and occur taking place the problem of flaw owing to inclusion, perhaps add Nb in manufacturing process owing to Nb is that separating out of precipitate suppressed recrystallize and grain growth, can not be obtained unit elongation and r value, so their upper limit is defined as 0.5%.
B:B is the element that secondary workability is improved, and suppresses the secondary processing crackle in the various processing after expander processing.In order to obtain its effect, 0.0003% or more than be necessary, therefore it is defined as lower limit.Again owing to make plasticity deteriorations such as the unit elongation of material and r value, so its upper limit is defined as 0.0030%.
Secondly, with the steel band that uses SUS436L/0.8mmt, 1.0mmt by roll forming and make TIG welded tube, the butt seam welding pipe of φ 25.4mm with various tubulation conditions, rectification condition, heat-treat condition.To each welded tube of making, carry out expander processing with the multistage drift through 4 procedures (φ 30, φ 38, φ 45, φ 51), according in whole operations flawless being arranged, describe with the result who estimates expander.
In order to obtain the difference of hardness Δ HV of welded tube, with the 500g loading and with the Vickers' hardness of 0.5mm or 0.2mm measuring space welding zone, get its mean value with micro Vickers.And the Vickers' hardness in mother metal district except the welding zone, to full week measuring 7 points with the 500g loading at interval with 45 °, is estimated with its mean value.
About the ratio of wall thickness, as the welding zone wall thickness, the mother metal district, estimates as the mother metal wall thickness with the mean value at 7 at the position of measuring mother metal district Vickers' hardness with the thickest position, welding zone.
Vickers hardness hv to the welding zone
WVickers hardness hv with mother metal
MDifference Δ the HV (=HV of hardness
W-HV
M) and the bead thickness T of welding zone
WWall thickness T with the mother metal district
MRatio RT (=T
W/ T
M) observe with the relation of tube expanding workability evaluation result, in Fig. 5 ● shown in like that, difference of hardness Δ HV less than 10 or difference of hardness Δ HV are 10～30, the occasion of its wall ratio RT less than 1.05, and crackle appears in the direction of principal axis (vertically) in the welding zone in expander processing.
Secondly, as among Fig. 5 ▲ shown in like that, difference of hardness Δ HV be 10～30 or difference of hardness Δ HV greater than 30, wall ratio is greater than 1.3 occasion, because the tube axial direction displacement is poor, shear strain between the two increases, and near the mother metal district the welding zone crackle takes place along inclined direction.
On the other hand, such shown in ◇ among Fig. 5, at difference of hardness Δ HV is that 10～40 scope, wall ratio RT are 1.05～1.3 scope, although small crackle occurs, but 2 times expander processing of parent tube is possible, and is for fine crack being suppressed at existing degree, such shown in among Fig. 5, HV is preferably 10～30 scope at the difference of hardness Δ, and wall ratio RT is preferably 1.1～1.25 scope.
The limited range of the girth correct amount after secondly, just being shaped, welding (girth before (girth one is corrected the back girth before correcting)/rectification) * 100 (%) is described.As shown in Figure 6, when girth correct amount less than 0.5%, the hardness of welding zone increases less, can not obtain expander and process desired above-mentioned welding zone intensity.On the other hand, greater than 2.0% occasion, welding zone hardness is sufficiently high at the girth correct amount, but the hardness increase in mother metal district is also big, and the processibility deterioration in mother metal district increases.Therefore, the girth correct amount after being shaped, welding is 0.5～2.0%, and is necessary.
The limited range of the thermal treatment temp after at last, utilization Fig. 7 just is shaped, welds, corrects is described.Thermal treatment can be replied the mother metal plasticity after the strain that is caused by shaping, welding, rectification, adjusts the strength balance in welding zone and mother metal district.At this, the plasticity of the mother metal that this answer causes when 700 ℃ of less thaies is replied insufficient, loses heat treated meaning.On the other hand, in the occasion that is higher than 850 ℃, the intensity of welding zone (hardness) descends, and becomes and mother metal district same degree, can not obtain the balance that expander is processed desired welding zone intensity and strength of parent.Therefore, during thermal treatment after forming, weld, correcting, thermal treatment temp is preferably 700～850 ℃ scope.
Embodiment
(embodiment 1)
Use the 1.0mm Plate Steel of composition shown in the table 1, according to correct amount behind molding condition, the tubulation, thermal treatment temp are changed, and make TIG welded tube, the butt seam welding pipe of φ 25.4mm.To the welded tube of making, with the eccentric expander of 5 procedures of multistage drift (to φ 25.4mm welded tube, expander is φ 30, φ 38, φ 45, φ 51, φ 51 eccentric expanders (side-play amount 13mm)), carry out the processing of multistage expander, by being arranged in whole operations, flawless estimates expander.In addition, also can take place with the welding zone through so strict expander processing is the crackle of starting point, therefore controls the intensity etc. of welding bead aptly and makes.
[table 1]
| Steel grade | Composition (quality %) | Unit elongation (%) ※ 1 | Average r value ※ 2 | Remarks | |||||||||||
| C | Si | Mn | P | S | Cr | Mo | Ti | Nb | N | B | |||||
| Example of the present invention | A | 0.004 | 0.09 | 0.14 | 0.024 | 0.0018 | 17.3 | 1.15 | 0.23 | - | 0.011 | 0.007 | 34 | 1.9 | |
| B | 0.005 | 0.08 | 0.12 | 0.022 | 0.0025 | 17.4 | 0.51 | 0.22 | - | 0.012 | 0.008 | 35 | 1.7 | ||
| C | 0.008 | 0.47 | 0.35 | 0.018 | 0.0034 | 11.2 | 0.03 | 0.24 | - | 0.013 | 0.011 | 37 | 1.8 | ||
| D | 0.013 | 0.48 | 0.11 | 0.025 | 0.0024 | 19.2 | 0.05 | - | 0.42 | 0.013 | 0.005 | 31 | 1.5 | ||
| E | 0.004 | 0.17 | 0.14 | 0.025 | 0.0035 | 19.2 | 1.89 | 0.14 | 0.26 | 0.014 | 0.009 | 32 | 1.8 | ||
| F | 0.006 | 0.10 | 0.12 | 0.023 | 0.0025 | 22.3 | 1.62 | 0.18 | 0.30 | 0.011 | 0.005 | 30 | 1.7 | ||
| G | 0.009 | 0.96 | 0.95 | 0.02 | 0.0021 | 13.9 | 0.47 | 0.15 | 0.30 | 0.009 | 0.007 | 31 | 1.5 | ||
| Comparative example | H | 0.085 | 0.03 | 0.70 | 0.032 | 0.023 | 16.7 | - | - | - | 0.032 | - | 28 | 1.1 | SUS430 |
_: the data that depart from the scope of the invention
※ 1: as welded tube, should become the unit elongation (%) of the direction of circumferential direction under the situation of shaping-welding
※ 2: in rolling direction, with rolling vertical direction, be respectively r with the r value of rolling direction at 45
0, r
90, r
45Situation under,
[table 2]
| No. | Steel grade | Manufacturing process | Welding process | Sizing rate (%) | The tubulation postheat treatment | Circumferential direction unit elongation (%) | Eccentric expander | |
| Example of the present invention | 1 | A | Roll forming (low strain) | TIG | 0.5 | Do not have | 28 | ○ |
| 2 | A | Roll forming (low strain) | ERW | 1.5 | Do not have | 15 | ○ | |
| 3 | B | Roll forming (low strain) | TIG | 0.7 | Do not have | 25 | ○ | |
| 4 | B | Roll forming (low strain) | ERW | 1.0 | Do not have | 21 | ○ | |
| 5 | C | Roll forming (low strain) | TIG | 0.8 | Do not have | 23 | ○ | |
| 6 | C | Roll forming (low strain) | ERW | 1.2 | Do not have | 18 | ○ | |
| 7 | D | Roll forming (low strain) | TIG | 0.7 | Do not have | 22 | ○ | |
| 8 | D | Roll forming (low strain) | ERW | 0.5 | Do not have | 26 | ○ | |
| 9 | E | Roll forming (low strain) | TIG | 1.3 | Do not have | 17 | ○ | |
| 10 | E | Roll forming (low strain) | TIG | 0.7 | Do not have | 24 | ○ | |
| 11 | F | Roll forming (low strain) | TIG | 0.5 | Do not have | 23 | ○ | |
| 12 | F | Roll forming (low strain) | TIG | 0.6 | Do not have | 24 | ○ | |
| 13 | G | Roll forming (low strain) | TIG | 0.8 | Do not have | 21 | ○ | |
| 14 | G | Roll forming (low strain) | TIG | 0.5 | Do not have | 25 | ○ | |
| 15 | A | Roll forming | TIG | 1.5 | 800℃ | 23 | ○ | |
| 16 | B | Roll forming | TIG | 1.8 | 850℃ | 24 | ○ | |
| 17 | C | Roll forming | TIG | 0.9 | 750℃ | 28 | ○ | |
| 18 | D | Roll forming | TIG | 1.2 | 800℃ | 22 | ○ | |
| 19 | E | Roll forming | TIG | 0.5 | 800℃ | 23 | ○ | |
| 20 | F | Roll forming | TIG | 0.7 | 800℃ | 21 | ○ | |
| 21 | G | Roll forming | TIG | 0.8 | 800℃ | 23 | ○ | |
| Comparative example | 22 | A | Roll forming | ERW | 1.0 | Do not have | 11 | △ |
| 23 | B | Roll forming | ERW | 1.1 | Do not have | 13 | △ | |
| 24 | C | Roll forming | TIG | 1.0 | 500℃ | 14 | △ | |
| 25 | D | Roll forming | TIG | 0.9 | 600℃ | 9 | × | |
| 26 | E | Roll forming | TIG | 0.8 | Do not have | 8 | × | |
| 27 | F | Roll forming | TIG | 1.2 | Do not have | 6 | × | |
| 28 | G | Roll forming | TIG | 0.9 | Do not have | 11 | △ | |
| 29 | H | Roll forming | TIG | 0.5 | 750℃ | 14 | × | |
| 30 | H | Roll forming | TIG | 0.5 | 800℃ | 17 | * (welding zone) | |
| 31 | H | Roll forming (low strain) | TIG | 0.5 | Do not have | 13 | × |
Zero: it is good to be shaped; △: necking down takes place; *: crackle takes place
The result that the eccentric expander of such various welded tubes is estimated shown in the his-and-hers watches 2 is, high purity ferritic steel for composition that as No.1～14, has the scope of the invention and raw material characteristics, surpass 1 times of hole type roll external diameter at interval and be not more than 2 times by the roller that makes the spy open the interconnected hole type roll of 2002-239626 communique etc. and dispose like that, form the bending and the recurvation of process, the shaping strain is reduced.Specifically, roller external diameter 50mm, roller at interval 10 sections of the hole type rolls of 52mm along the interconnected shaping of tubulation direction.About the sizing amount behind so low strained tubulation, by with girth than with the sizing rate be controlled at 1.5% or below, the unit elongation that can guarantee circumferential direction is 15% or necking down and crackle above, that do not see eccentric expander district, obtains sufficient eccentric expander.And, the tubulation material that obtains about the common roll forming of the such warp in No.15～21, behind tubulation, sizing by heat-treating at 700～850 ℃, ductility is recovered, the circumferential direction unit elongation be 15% or more than, do not see the necking down and the crackle in eccentric expander district, obtain sufficient expander.On the other hand, as the low strain tubulation of No.22～28 and sizing amount and the occasion or the lower occasion of thermal treatment temp of not heat-treating etc., the welded tube of circumferential direction unit elongation 15～10%, see the generation of necking down in its eccentric expander district, the circumferential direction unit elongation be 10% or following material crackle appears, obviously, can not use as the important safety parts of automobile etc.
On the other hand, the steel grade H (SUS430) of No.29～31 is during as starting material, and the unit elongation of material and r value are lower, and the deterioration in characteristics of welding zone, so eccentric expander district of mother metal and welding zone generation crackle can not be used with material as the eccentric expander of strictness.
(embodiment 2)
Use the steel plate of composition shown in the table 3, correct amount behind molding condition, the tubulation, thermal treatment temp are changed, make TIG welded tube, the butt seam welding pipe (ERW) of φ 25.4mm or φ 28.6mm.To the welded tube of making, (the welded tube expander of φ 25.4mm is φ 30, φ 38, φ 45, φ 51 with 4 procedures of multistage drift; The welded tube expander of φ 28.6mm is φ 38, φ 45, φ 51, φ 58) carry out expander processing, by being arranged in whole operations, flawless estimates expander, and it the results are shown in table 4.
[table 3]
| Steel grade | C | Si | Mn | Cr | Mo | Ti | Nb | N | Remarks |
| A B C D E F G H I | 0.004 0.005 0.008 0.013 0.004 0.006 0.009 0.070 0.016 | 0.09 0.08 0.47 0.48 0.17 0.10 0.96 0.16 0.45 | 0.14 0.12 0.35 0.11 0.14 0.12 0.95 0.61 0.12 | 17.3 17.4 11.2 19.2 19.2 22.3 13.9 16.2 19.3 | 1.15 0.51 - - 1.89 1.62 0.47 - - | 0.23 0.22 0.24 - 0.14 0.18 0.15 - - | - - - 0.42 0.26 0.30 0.30 - 0.59 | 0.011 0.012 0.013 0.013 0.014 0.011 0.009 0.020 0.019 | SUS436L YUS436S YUS432 YUS409D YUS180 YUS190 YUS220M YUS450MS SUS430 YUS180M |
[table 4]
| NO. | Steel grade | Welding process | Diameter (mm) | Thickness of slab (mm) | Girth correct amount (%) | Thermal treatment temp (℃) | The difference of hardness Δ HV of welding zone and mother metal | Welding bead compares T with mother metal thickness W/T M | Expander | |
| Example of the present invention | 1 | A | TIG | 25.4 | 0.8 | 1.5 | 800 | 25 | 1.15 | ◎ |
| 2 | A | TIG | 25.4 | 1.0 | 0.8 | - | 20 | 1.10 | ◎ | |
| 3 | A | ERW | 25.4 | 0.8 | 1.0 | - | 28 | 1.08 | ○ | |
| 4 | A | ERW | 28.6 | 1.0 | 1.5 | 750 | 32 | 1.08 | ○ | |
| 5 | B | TIG | 25.4 | 0.8 | 0.5 | 850 | 11 | 1.15 | ○ | |
| 6 | B | TIG | 25.4 | 1.0 | 1.8 | 800 | 32 | 1.20 | ◎ | |
| 7 | B | ERW | 28.6 | 1.0 | 0.7 | - | 22 | 1.10 | ◎ | |
| 8 | C | TIG | 25.4 | 0.8 | 0.5 | 700 | 10 | 1.23 | ◎ | |
| 9 | C | ERW | 25.4 | 1.0 | 1.5 | - | 32 | 1.18 | ○ | |
| 10 | C | ERW | 28.6 | 1.0 | 0.7 | - | 20 | 1.10 | ◎ | |
| 11 | D | TIG | 25.4 | 0.8 | 1.8 | 800 | 30 | 1.15 | ◎ | |
| 12 | D | ERW | 28.6 | 1.0 | 1.0 | - | 28 | 1.08 | ○ | |
| 13 | E | TIG | 25.4 | 1.0 | 2.0 | 800 | 33 | 1.20 | ○ | |
| 14 | E | ERW | 28.6 | 1.0 | 0.7 | 800 | 20 | 1.10 | ◎ | |
| 15 | F | TIG | 25.4 | 0.8 | 1.0 | - | 25 | 1.11 | ◎ | |
| 16 | F | ERW | 28.6 | 0.8 | 1.1 | 800 | 20 | 1.10 | ◎ | |
| 17 | G | TIG | 25.4 | 0.8 | 1.1 | 800 | 20 | 1.12 | ◎ | |
| 18 | G | ERW | 25.4 | 1.0 | 1.0 | 750 | 23 | 1.08 | ○ | |
| Comparative example | 19 | H | TIG | 25.4 | 1.0 | 1.0 | 850 | 45 | 1.20 | * * (2 operation) |
| 20 | H | ERW | 25.4 | 0.8 | 0.5 | 800 | 50 | 1.15 | * * (3 operation) | |
| 21 | I | TIG | 25.4 | 1.0 | 0.8 | 800 | 25 | 1.21 | * * (3 operation) | |
| 22 | I | ERW | 28.6 | 1.0 | 0.7 | 800 | 25 | 1.18 | * * (4 operation) | |
| 23 | A | TIG | 25.4 | 1.0 | 0.2 | - | 3 | 1.05 | * (2 operation) | |
| 24 | B | ERW | 28.6 | 1.0 | 0.3 | 800 | 8 | 1.08 | * (3 operation) | |
| 25 | C | TIG | 25.4 | 0.8 | 0.2 | 800 | 5 | 1.15 | * (2 operation) | |
| 26 | D | TIG | 28.6 | 0.8 | 0.3 | 800 | 5 | 1.20 | * (3 operation) | |
| 27 | E | TIG | 25.4 | 1.0 | 0.4 | 800 | 6 | 1.30 | * (3 operation) | |
| 28 | F | ERW | 28.6 | 1.0 | 0.3 | - | 8 | 1.20 | * (2 operation) | |
| 29 | A | TIG | 25.4 | 1.0 | 1.2 | 900 | 4 | 1.35 | * (3 operation) | |
| 30 | B | TIG | 25.4 | 0.8 | 1.9 | 900 | 4 | 1.42 | * (2 operation) | |
| 31 | C | ERW | 25.4 | 1.0 | 0.9 | 900 | 8 | 1.10 | * (2 operation) | |
| 32 | D | ERW | 28.6 | 1.0 | 0.8 | 950 | 7 | 1.12 | * (3 operation) | |
| 33 | E | ERW | 28.6 | 1.0 | 1.1 | 950 | 5 | 1.10 | * (3 operation) | |
| 34 | F | ERW | 28.6 | 1.0 | 1.8 | 950 | 5 | 1.07 | * (2 operation) | |
| 35 | G | TIG | 28.6 | 1.0 | 1.9 | 900 | 6 | 1.18 | * (3 operation) | |
| 36 | A | TIG | 25.4 | 0.8 | 0.8 | 800 | 20 | 1.04 | * (2 operation) | |
| 37 | B | ERW | 25.4 | 0.8 | 0.7 | 800 | 18 | 1.35 | * * (2 operation) | |
| 38 | C | ERW | 28.6 | 1.0 | 0.8 | 800 | 21 | 1.38 | * * (2 operation) | |
| 39 | D | TIG | 25.4 | 1.0 | 1.0 | 800 | 23 | 1.04 | * (3 operation) | |
| 40 | E | TIG | 28.6 | 0.8 | 0.6 | 800 | 15 | 1.33 | * * (3 operation) | |
| 41 | F | TIG | 25.4 | 0.8 | 1.2 | 800 | 25 | 1.35 | * * (2 operation) | |
| 42 | G | ERW | 28.6 | 1.0 | 0.7 | 800 | 18 | 1.03 | * (2 operation) |
Zero: fine crack (crackle＜3mm=; ◎: flawless; *: the welding zone longitudinal crack; Near tilted direction crackle * *: the welding zone mother metal.
Underscore part: the condition that departs from the scope of the invention
The result that the expander of the welded tube that different steel grades, difference are created conditions is estimated is, No.1～18 of the difference of hardness of the composition in the scope of the invention, welding zone Vickers' hardness and mother metal Vickers' hardness and mother metal and the ratio of bead thickness, irrelevant with welding process and pipe size, tube end does not have crackle or crackle very little, can carry out 2 times or more expander processing of parent tube no problemly.
On the other hand, composition departs from No.19～22 of the scope of the invention, and the hardness of welding zone increases, and therefore the processibility deterioration in mother metal district cracks near the mother metal tilted direction the welding zone.Because the correct amount behind the tubulation is different with annealing conditions, welding zone and less No.23～35 of mother metal difference of hardness Δ HV are in the initial stage process of 2 or 3 operations of expander operation, generation welding zone longitudinal crack.
Thin or thicker No.36～42 of welding bead, when welding bead is thicker, near the mother metal generation tilted direction crackle the welding zone; When welding bead is thin, in welding zone generation longitudinal crack.
As above narration, the present invention can provide the welded ferritic stainless steel tube of no mother metal crackle in expander processing environment for use, excellent in enlarging characteristics and eccentric of sternness of tolerance auto exhaust system and fuel system components etc.
Claims (5)
1. welded ferritic stainless steel tube that has excellent tube expanding workability is characterized in that: for welded ferritic stainless steel tube, through be shaped, welding, the unit elongation of circumferential direction in welded tube mother metal district after correcting be 15% or more than.
2. welded ferritic stainless steel tube that has excellent tube expanding workability is characterized in that: for a kind or 2 kinds welded ferritic stainless steel tube not containing with quality % score among 0.05～0.5% Ti, the Nb, the vickers hardness hv in the welding zone
WVickers hardness hv with mother metal
MDifference Δ the HV (=HV of hardness
W-HV
M) be 10～40 scope, the bead thickness T of welding zone
WWall thickness T with the mother metal district
MRatio RT (=T
W/ T
M) be 1.05～1.3.
3. the welded ferritic stainless steel tube that has excellent tube expanding workability according to claim 1 and 2, it is characterized in that: it contains C:0.001～0.015% in quality %, Si:0.01～1.0%, Mn:0.01～1.0%, P:0.01～0.03%, S:0.0005～0.010%, N:0.001～0.020%, Cr:11～25%, Mo:0.01～2.0%, Ti or Nb a kind or 2 kinds each 0.05～0.5%, B:0.0003～0.0030%, surplus is made up of Fe and unavoidable impurities, and uses following material plate: the unit elongation of the direction of the circumferential direction that should become the welded tube material plate be 30% or more than, average Lankford value (r value) be 1.5 or more than.
4. the manufacture method of the described welded tube of any one of claim 1～3 is characterized in that: be shaped and welding after, impose and count 0.5～2.0% rectification by girth.
5. the manufacture method of welded tube according to claim 4 is characterized in that: after being shaped, welding, correcting, anneal in 700～850 ℃.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP370616/2004 | 2004-12-22 | ||
| JP2004370616A JP4907079B2 (en) | 2004-12-22 | 2004-12-22 | Ferritic stainless steel welded pipe with excellent pipe workability and ferritic stainless steel sheet for welded pipe |
| JP005023/2005 | 2005-01-12 |
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| Publication Number | Publication Date |
|---|---|
| CN1918313A true CN1918313A (en) | 2007-02-21 |
| CN100513610C CN100513610C (en) | 2009-07-15 |
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| CNB2005800047810A Active CN100513610C (en) | 2004-12-22 | 2005-12-19 | Welded ferritic stainless steel tube having excellent tube expanding workability |
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|---|---|
| JP (1) | JP4907079B2 (en) |
| CN (1) | CN100513610C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101862764A (en) * | 2010-04-07 | 2010-10-20 | 雷丙旺 | Method for manufacturing large-diameter thick-wall seamless steel pipe |
| CN102941394A (en) * | 2012-11-15 | 2013-02-27 | 武汉船用机械有限责任公司 | Method for overlaying welding of duplex stainless steel |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7754344B2 (en) | 2004-12-22 | 2010-07-13 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferritic stainless steel welded pipe superior in expandability |
| JP5000472B2 (en) * | 2007-12-11 | 2012-08-15 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel welded pipe excellent in pipe expansion workability and manufacturing method thereof |
| JP2009182235A (en) * | 2008-01-31 | 2009-08-13 | Tokyo Electron Ltd | Load lock apparatus and substrate cooling method |
| JP2009215633A (en) * | 2008-03-12 | 2009-09-24 | Nisshin Steel Co Ltd | Ferritic stainless steel for oil supply system member |
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Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0641689A (en) * | 1992-06-22 | 1994-02-15 | Nippon Steel Corp | High cr steel tube excellent in workability |
| JP4223140B2 (en) * | 1999-05-20 | 2009-02-12 | 日新製鋼株式会社 | Method for producing ferritic stainless steel welded tube with good workability |
| JP2003277891A (en) * | 2002-03-27 | 2003-10-02 | Nisshin Steel Co Ltd | Automobile fuel tank or oil feeding pipe made of stainless steel having excellent impact resistance |
| JP2004010967A (en) * | 2002-06-06 | 2004-01-15 | Nisshin Steel Co Ltd | Ferritic stainless steel pipe with excellent fabrication quality |
| JP4274986B2 (en) * | 2004-03-25 | 2009-06-10 | 日新製鋼株式会社 | Stainless steel welded pipe for oil supply pipe |
-
2004
- 2004-12-22 JP JP2004370616A patent/JP4907079B2/en active Active
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- 2005-12-19 CN CNB2005800047810A patent/CN100513610C/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101862764A (en) * | 2010-04-07 | 2010-10-20 | 雷丙旺 | Method for manufacturing large-diameter thick-wall seamless steel pipe |
| CN102941394A (en) * | 2012-11-15 | 2013-02-27 | 武汉船用机械有限责任公司 | Method for overlaying welding of duplex stainless steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2006176824A (en) | 2006-07-06 |
| JP4907079B2 (en) | 2012-03-28 |
| CN100513610C (en) | 2009-07-15 |
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