EP1734142A1 - Corrosion-resistant steel excellent in toughness of base metal and weld and process for producing the same - Google Patents
Corrosion-resistant steel excellent in toughness of base metal and weld and process for producing the same Download PDFInfo
- Publication number
- EP1734142A1 EP1734142A1 EP04732471A EP04732471A EP1734142A1 EP 1734142 A1 EP1734142 A1 EP 1734142A1 EP 04732471 A EP04732471 A EP 04732471A EP 04732471 A EP04732471 A EP 04732471A EP 1734142 A1 EP1734142 A1 EP 1734142A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- toughness
- base metal
- corrosion
- steel
- less
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000010953 base metal Substances 0.000 title claims abstract description 39
- 239000010935 stainless steel Substances 0.000 title claims abstract description 20
- 238000000034 method Methods 0.000 title description 6
- 230000008569 process Effects 0.000 title description 3
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 61
- 239000010959 steel Substances 0.000 claims abstract description 61
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 33
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 29
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 27
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 25
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 23
- 229910052802 copper Inorganic materials 0.000 claims abstract description 21
- 238000004519 manufacturing process Methods 0.000 claims description 15
- 230000009466 transformation Effects 0.000 claims description 12
- 238000001816 cooling Methods 0.000 claims description 9
- 238000005496 tempering Methods 0.000 claims description 5
- 238000005098 hot rolling Methods 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000005260 corrosion Methods 0.000 description 35
- 230000007797 corrosion Effects 0.000 description 34
- 238000012360 testing method Methods 0.000 description 14
- 229910000859 α-Fe Inorganic materials 0.000 description 13
- 230000000694 effects Effects 0.000 description 12
- 239000011248 coating agent Substances 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 239000013535 sea water Substances 0.000 description 6
- 230000006872 improvement Effects 0.000 description 5
- 229910052761 rare earth metal Inorganic materials 0.000 description 5
- 150000002910 rare earth metals Chemical class 0.000 description 5
- 238000003466 welding Methods 0.000 description 5
- 238000005275 alloying Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 230000015556 catabolic process Effects 0.000 description 3
- 238000006731 degradation reaction Methods 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000009863 impact test Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
Images
Classifications
-
- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
-
- 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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- 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
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
-
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
Definitions
- the present invention relates to a corrosion-resistant steel excellent in toughness of a base metal and a weld portion, and a method of manufacturing the same, and more specifically, a corrosion-resistant steel used in various forms under various corrosive environments, such as various containers, vacuum vessels, low-temperature heat exchangers and bathroom components used under corrosive environment with dewing or under indoor environment; such as bridge, support columns, tunnel reinforcing components, interior and exterior materials for buildings, roof materials and fittings used under aerial corrosive environment; such as various reinforcing structures and support columns used under corrosive environment with concrete; and such as marine vessels, bridges, piles, sheet piles and marine structures used under corrosive environments with seawater.
- various corrosive environments such as various containers, vacuum vessels, low-temperature heat exchangers and bathroom components used under corrosive environment with dewing or under indoor environment
- bridge, support columns, tunnel reinforcing components interior and exterior materials for buildings, roof materials and fittings used under aerial corrosive environment
- Steels used under various corrosive environments such as high-temperature and high-humidity corrosive environment, corrosive environment with dewing, aerial corrosive environment, corrosive environment with city water, corrosive environment with soil, corrosive environment with concrete, and corrosive environment with seawater, are generally provided with some anti-corrosion measures.
- corrosive environments such as high-temperature and high-humidity corrosive environment, corrosive environment with dewing, aerial corrosive environment, corrosive environment with city water, corrosive environment with soil, corrosive environment with concrete, and corrosive environment with seawater.
- any steels containing certain levels of Cr generally became more likely to cause local corrosion as the corrosive environment became more severe, so that as a countermeasure for this problem, further increase in the concentration of Cr or Mo has been a most general technical means for improving the resistivity against corrosion.
- the present invention is aimed at providing a low-cost, corrosion-resistant steel showing a large corrosion resistance under various corrosive environments such as corrosive environment with dewing, aerial corrosive environment, corrosive environment with city water, and corrosive environment with seawater, and excellent in the toughness in the heat affected zone (HAZ).
- various corrosive environments such as corrosive environment with dewing, aerial corrosive environment, corrosive environment with city water, and corrosive environment with seawater, and excellent in the toughness in the heat affected zone (HAZ).
- the present inventors made extensive studies from every aspect, in order to develop a steel showing excellent corrosion resistance under various corrosive environments such as corrosive environment with dewing, aerial corrosive environment, corrosive environment with city water, corrosive environment with concrete, and corrosive environment with seawater.
- various corrosive environments such as corrosive environment with dewing, aerial corrosive environment, corrosive environment with city water, corrosive environment with concrete, and corrosive environment with seawater.
- this sort of steel typically produces coarse ferrite when heated at 1200°C or more during welding, due to its wide range of ferrite phase transformation, so that the toughness may degrade to a considerable degree, and may cause cracks and the like after welding.
- the present inventors then further went through a series of experiments, and found out that a mode of generation of the coarse ferrite phase transformation during welding can be estimated based on a parameter Tp below, expressed using amounts of addition of alloying elements.
- the parameter Tp can be expressed using concentrations of ferrite-forming elements (Cr, Al) and austenite-forming elements (Mn, Ni, for example) which suppress production of ferrite phase.
- concentrations of ferrite-forming elements Cr, Al
- austenite-forming elements Mn, Ni, for example
- C is an element improving the strength, but addition to an amount exceeding a predetermined level results in degradation of the toughness in the heat affected zone (HAZ).
- the upper limit of the C concentration is therefore set to 0.2%.
- Si is effectively added to a steel containing 2% or more of Cr, as a deoxidizer and a strengthening element, wherein the concentration thereof less than 0.01% results in only an insufficient effect of deoxidization, whereas the concentration exceeding 2.0% not only saturates the effect but also adversely degrades the toughness of the heat affected zone (HAZ).
- the range of Si concentration is therefore limited from 0.01% and 2.0%, both ends inclusive.
- Cr Cr is added in order to ensure a desirable level of corrosion resistance, similarly to Al, wherein an amount of addition of 3% or more exhibits the effect, whereas the amount of addition exceeding 11% not only increases the cost, but also impairs again the toughness of the heat affected zone (HAZ).
- the upper limit of the Cr concentration is set to 11%.
- Al is an important element, similar to Cr, in view of ensuring a desirable level of corrosion resistance in the present invention, wherein the concentration of Al is necessarily set to 0.1% or more in view of ensuring a desirable level of corrosion resistance.
- the amount of addition exceeding 2% extremely widens a temperature range causing the ferrite phase transformation.
- the concentration of Al is therefore limited to 0.1% to 2%, both ends inclusive.
- Mn in the present invention functions mainly as improving the strength and as an austenite-forming element, and is added to suppress generation of coarse ferrite promoted by Cr and Al added in view of improving the corrosion resistance.
- Cr and Al are ferrite-forming elements as well-known, wherein large amounts of addition of these elements may give a ferrite single phase structure over a range from solidification point to room temperature, without causing transformation, and may considerably degrade the toughness not only in the base metal, but also in the heat affected zone (HAZ).
- the present inventors made systematic experiments aiming at improving the toughness of the heat affected zone (HAZ) without causing the corrosion resistance, and found out that addition of Mn can avoid the problem. Specific conditions for limitation therefor will be described later, wherein Mn is necessarily added to as much as 0.1% or more, but the amount of addition exceeding 4% enhances the hardening property, so that the addition is limited up to 4%.
- N The less N is contained, the more preferable, because a large amount of addition thereof to steel plate may lower the toughness of the base metal and the heat affected zone (HAZ), so that the upper limit of concentration thereof is set to 0.02%.
- P The less P is contained, the more preferable, because abundance thereof lowers the toughness, so that the upper limit of concentration thereof is set to 0.03%.
- concentration thereof ascribable to inevitable contamination is preferably minimized as possible.
- S The less S is contained, the more preferable, too, because abundance thereof lowers pitting resistance, so that the upper limit of concentration thereof is set to 0.01%. Similarly to P, also the concentration of S ascribable to inevitable contamination is preferably minimized as possible.
- the present invention further allows addition of the elements below.
- Cu, Ni Both of Cu and Ni exhibit effects of improving the strength, and of suppressing the ferrite generation.
- Ni has an effect of improving the toughness of the base metal and the heat affected zone (HAZ).
- HZ heat affected zone
- Both of the concentrations of Cu and Ni are therefore set to 0.1 to 4%.
- Mo Mo added to as much as 0.01% or more to a steel added with Cr and Al exhibits an effect of suppressing generation and growth of pitting, without impairing the toughness of the base metal, whereas an amount of addition exceeding 1.0% not only saturates the effect but also degrades the toughness.
- the concentration of Mo is therefore set to 0.01% to 1.0%.
- Nb is an element improving the strength and toughness without impairing the corrosion resistance, wherein the effect thereof is recognizable at a concentration of as small as 0.005%, whereas the concentration exceeding 0.05% considerably degrades the toughness of the heat affected zone (HAZ).
- the concentration of Nb is therefore set to 0.005% to 0.05%.
- V is an element improving the strength without impairing the corrosion resistance, similar to Nb, wherein the effect thereof is recognizable at a concentration of as small as 0.01% or more, whereas a large amount of addition degrades the toughness as well-known.
- the upper limit of the V concentration is set to 0.1%.
- Ti is an element contributive to refinement of crystal grains at high temperatures through production of nitride, and can particularly improve the toughness of the heat affected zone (HAZ), without impairing the corrosion resistance. Both of refinement of the crystal' grains and improvement in the toughness are recognizable at a concentration of as small as 0.005% or more, whereas addition to as much as exceeding 0.03% adversely degrades the toughness of the base metal and the heat affected zone (HAZ), due to deposition of a large amount of carbide. The range of concentration is therefore set to 0.005% to 0.03%.
- Ca, Mg are elements capable of improving the corrosion resistance in a steel containing Cr and Al. Although much of the mechanism thereof remain unclear at present, it has been made clear that improvement in the corrosion resistance is recognizable at a concentration of as small as 5 ppm or more for the both, whereas the amount of addition exceeding 500 ppm not only saturates the effect of improving the corrosion resistance, but also tends to degrade the toughness. The concentrations of these elements are therefore set to 5 ppm to 500 ppm, both ends inclusive.
- REM rare earth metals
- Fig. 1 shows results of measurement and observation of transformation point and generation behavior of coarse ferrite, obtained when materials composed of a 0.015%C-0.15%Si steel (P, S and N are within the ranges of the present invention) as a base, added with Mn, Cr and A1, and for some cases with Cu and/or Ni, were subjected to welding cycles. It is found from Fig. 1 that generation of the coarse ferrite phase is suppressed when value of the parameter Tp, plotted on the abscissa, reaches and exceeds 1150.
- P, S and N 0.015%C-0.15%Si steel
- Fig. 2 shows, together with values of the parameter Tc, results of measurement of the toughness of a 0.02 to 0.05%C-0.25%Si steel as a base, added with Mn: 1.50 to 3.72%, Cr: 5.1 to 10.3% and Al: 0.8 to 1.5%, wherein a 20-mm-thick steel plate was manufactured by hot rolling, and test pieces were collected from a portion having a quarter thickness (5 mm) in the longitudinal direction. It is found from Fig. 2 that a range of the parameter Tc of 600 or more can ensure an absorption energy at -5°C (vE- 5 ) of as desirable as 100 J or more. The present invention therefore sets the lower limit thereof to 600.
- the steel slab can be made by the ingot making/breaking down method, continuous casting method and the like.
- the steel slab may further be processed to give a steel plate by hot rolling, hot forging or the like, or may be hot-worked to give an arbitrary geometry corresponding to a user's need, such as steel pipes represented by seamless steel pipe, shape steels and the like.
- the hot working can be followed by air-cooling, for example. Tempering at a temperature not higher than A c1 transformation point, aiming at further improving the strength, will never interfere the effects of the present invention.
- the corrosion-resistant steel according to the present invention is applicable, for example, to various corrosive environments, such as high-temperature and high-humidity corrosive environment, corrosive environment with dewing, aerial corrosive environment, corrosive environment with city water, corrosive environment with soil, corrosive environment with concrete, corrosive environment with seawater, and corrosive environments based on any combinations of them.
- various corrosive environments such as high-temperature and high-humidity corrosive environment, corrosive environment with dewing, aerial corrosive environment, corrosive environment with city water, corrosive environment with soil, corrosive environment with concrete, corrosive environment with seawater, and corrosive environments based on any combinations of them.
- 5-mm-thick corrosion test pieces were collected by cutting from a test steel plate, wherein some of them were provided with Zn-base coating (coating thickness: 15 to 25 ⁇ m), and then subjected to the test under conditions described below.
- the uncoated pieces were subjected to a one-hundred-day exposure test in a room with an air conditioner.
- Humid Environment The test pieces were kept at -20°C for 2 hours, and then kept in an environment of 95% humidity at 25°C for 4 hours, and this cycle was repeated 13000 times. Size of rust spot was scored for all samples.
- Salt Damage Environment The test pieces were exposed to a coastal splash zone for 17 months.
- steels marked with L to U are those according to comparative examples out of scope of the present invention. More specifically, steels L, M and N, having the concentrations of C, Si and Mn, respectively, exceeding the upper limits specified by the present invention, showed almost desirable corrosion resistance, but showed considerable degradation in the toughness.
- the steel marked with L showed a toughness ( ⁇ vTrs) of the heat affected zone (HAZ) of -40°C, indicating a large decrease.
- the steel marked with Q having the Al concentration exceeding the upper limit, showed a desirable corrosion resistance, but was degraded in the toughness of the base metal.
- the steel marked with R having Ni added as exceeding the upper limit, again showed a desirable corrosion resistance, but was poor in the toughness of the base metal.
- All of the steels marked with S, T and U have the concentrations of the individual element fallen within the ranges of the present invention, but have value(s) of the parameter(s) Tp and/or Tc out of the ranges of the present invention. More specifically, the steel marked with S is an example having only the parameter Tp fallen out of the range of the present invention, showing a degraded toughness of the heat affected zone (HAZ) of -55°C.
- the steel marked with T is an example having only the parameter Tc fallen out of the range of the present invention, showing a degraded toughness of the base metal of 83 J.
- the last steel marked with U is an example having both of the parameters Tp and Tc fallen out of the ranges of the present invention, showing degradation both in the toughness of the base metal and the heat affected zone (HAZ).
- the present invention can provide, at low costs, a steel excellent not only in the corrosion resistance in corrosive environment with dewing, and in other various corrosive environments such as indoor environment, aerial corrosive environment and corrosive environment with seawater, but also in the toughness of the heat affected zone (HAZ) which is important for weld structures, and can make a huge contribution to industrial development.
- HAZ heat affected zone
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
- The present invention relates to a corrosion-resistant steel excellent in toughness of a base metal and a weld portion, and a method of manufacturing the same, and more specifically, a corrosion-resistant steel used in various forms under various corrosive environments, such as various containers, vacuum vessels, low-temperature heat exchangers and bathroom components used under corrosive environment with dewing or under indoor environment; such as bridge, support columns, tunnel reinforcing components, interior and exterior materials for buildings, roof materials and fittings used under aerial corrosive environment; such as various reinforcing structures and support columns used under corrosive environment with concrete; and such as marine vessels, bridges, piles, sheet piles and marine structures used under corrosive environments with seawater.
- Steels used under various corrosive environments, such as high-temperature and high-humidity corrosive environment, corrosive environment with dewing, aerial corrosive environment, corrosive environment with city water, corrosive environment with soil, corrosive environment with concrete, and corrosive environment with seawater, are generally provided with some anti-corrosion measures. In recent years, in view of improving reliability, simplifying manufacturing and application processes, achieving maintenance-free, saving resources and the like, there have been increasing trends in using Cr-containing steels and stainless steels, for the purpose of improving corrosion resistance of the steel base. Most of conventional techniques have, however, failed in providing a practical measure from an economical point of view, because improvement in the corrosion resistance has resulted in increase in material cost, and have sometimes resulted in only a limited range of applications due to poor strength when austenitic steels were used.
- As seen in the above-described examples, any steels containing certain levels of Cr generally became more likely to cause local corrosion as the corrosive environment became more severe, so that as a countermeasure for this problem, further increase in the concentration of Cr or Mo has been a most general technical means for improving the resistivity against corrosion.
- In recent years, there have been proposed steels added with Al besides Cr, aiming at improving the corrosion resistance, or both of the corrosion resistance and workability, as disclosed in Japanese Patent Application Laid-Open
Nos. 5-279791 6-179949 6-179950 6-179951 6-212256 6-212257 7-3388 11-350082 - After considering the above-described situations, the present invention is aimed at providing a low-cost, corrosion-resistant steel showing a large corrosion resistance under various corrosive environments such as corrosive environment with dewing, aerial corrosive environment, corrosive environment with city water, and corrosive environment with seawater, and excellent in the toughness in the heat affected zone (HAZ).
- Aiming at achieving the above-described objects, the present inventors made extensive studies from every aspect, in order to develop a steel showing excellent corrosion resistance under various corrosive environments such as corrosive environment with dewing, aerial corrosive environment, corrosive environment with city water, corrosive environment with concrete, and corrosive environment with seawater. First, after extensive investigations into techniques for improving the corrosion resistance under the above-described various environments, as well as the toughness of the weld portion, the present inventors found that a steel containing 3 to 11% of Cr, added with 0.1 to 2% of Al, showed a very excellent corrosion resistance under the above-described various corrosive environments. However, this sort of steel typically produces coarse ferrite when heated at 1200°C or more during welding, due to its wide range of ferrite phase transformation, so that the toughness may degrade to a considerable degree, and may cause cracks and the like after welding. The present inventors then further went through a series of experiments, and found out that a mode of generation of the coarse ferrite phase transformation during welding can be estimated based on a parameter Tp below, expressed using amounts of addition of alloying elements. The parameter Tp can be expressed using concentrations of ferrite-forming elements (Cr, Al) and austenite-forming elements (Mn, Ni, for example) which suppress production of ferrite phase. The present inventors found out that production of ferrite at higher temperatures can be suppressed, when the parameter Tp has a value of not smaller than a predetermined level.
- On the other hand, addition of some austenite-forming elements described in the above can suppress production of the coarse ferrite phase in the weld portion, but addition of large amounts of the alloying elements may promote formation of a low-temperature-transformation-forming phase with poor toughness in the process of cooling after rolling of the base metal, and thereby tends to lower the toughness of the base metal. The present inventors then made extensive studies on preventing such embrittlement, defined a parameter Tc which specifies concentrations of the alloying elements capable of ensuring a desirable level of toughness of the base metal after rolling, and found out that a desirable level of toughness can be ensured when the parameter Tc has a value of not smaller than a predetermined level.
- Basic concepts of the present invention are as follows.
- (1) A corrosion-resistant steel excellent in toughness of a base metal and a weld portion, containing, in % by weight:
- C: 0.2% or less;
- Si: 0.01 to 2.0%;
- Mn: 0.1 to 4%;
- P: 0.03% or less;
- S: 0.01% or less;
- Cr: 3 to 11%;
- Al: 0.1 to 2%; and
- N: 0.02%, and
- (2) The corrosion-resistant steel excellent in toughness of a base metal and a weld portion according to (1), further containing, in % by weight, any one of, or two or more elements selected from the group consisting of:
- Cu: 0.1 to 4%;
- Ni: 0.1 to 4%;
- Mo: 0.01 to 1%;
- V: 0.01 to 0.1%;
- Nb: 0.005 to 0.050%;
- Ti: 0.005 to 0.03%;
- Ca: 0.0005 to 0.05%;
- Mg: 0.0005 to 0.05%; and
- REM: 0.001 to 0.1%.
- (3) A method of manufacturing a corrosion-resistant steel excellent in toughness of a base metal and a weld portion, including the steps of:
- heating a steel slab;
- the steel slab containing, in % by weight:
- C: 0.2% or less;
- Si: 0.01 to 2.0%;
- Mn: 0.1 to 4%;
- P: 0.03% or less;
- S: 0.01% or less;
- Cr: 3 to 11%;
- Al: 0.1 to 2%; and
- N: 0.02%, and
forming a steel plate by hot rolling of the steel slab; and
cooling the steel plate by air. - (4) The method of manufacturing a corrosion-resistant steel excellent in toughness of a base metal and a weld portion according to (3), wherein the steel slab further contains, in % by weight, any one of, or two or more elements selected from the group consisting of:
- Cu: 0.1 to 4%;
- Ni: 0.1 to 4%;
- Mo: 0.01 to 1%;
- V: 0.01 to 0.1%;
- Nb: 0.005 to 0.050%;
- Ti: 0.005 to 0.03%;
- Ca: 0.0005 to 0.05%;
- Mg: 0.0005 to 0.05%; and
- REM: 0.001 to 0.1%.
- (5) The method of manufacturing a corrosion-resistant steel excellent in toughness of a base metal and a weld portion according to (3), further including, after the step of cooling the steel plate by air, tempering the steel plate at a temperature of Ac1 transformation point or below.
- (6) The method of manufacturing a corrosion-resistant steel excellent in toughness of a base metal and a weld portion according to (4), further including, after the step of cooling the steel plate by air, tempering the steel plate at a temperature of Ac1 transformation point or below.
-
- Fig. 1 is a graph showing relations between the Tp values (calculated values of A4 transformation point) and measured transformation points, and relations between the Tp values and presence or absence of δ ferrite; and
- Fig. 2 is a graph showing relations between the Tc values and the toughness (vE-5) of the base metal.
- Paragraphs below will explain constitutive elements of the inventive corrosion-resistant steel, concentrations thereof and the like.
- C: C is an element improving the strength, but addition to an amount exceeding a predetermined level results in degradation of the toughness in the heat affected zone (HAZ). The upper limit of the C concentration is therefore set to 0.2%.
- Si: Si is effectively added to a steel containing 2% or more of Cr, as a deoxidizer and a strengthening element, wherein the concentration thereof less than 0.01% results in only an insufficient effect of deoxidization, whereas the concentration exceeding 2.0% not only saturates the effect but also adversely degrades the toughness of the heat affected zone (HAZ). The range of Si concentration is therefore limited from 0.01% and 2.0%, both ends inclusive.
- Cr: Cr is added in order to ensure a desirable level of corrosion resistance, similarly to Al, wherein an amount of addition of 3% or more exhibits the effect, whereas the amount of addition exceeding 11% not only increases the cost, but also impairs again the toughness of the heat affected zone (HAZ). The upper limit of the Cr concentration is set to 11%.
- Al: Al is an important element, similar to Cr, in view of ensuring a desirable level of corrosion resistance in the present invention, wherein the concentration of Al is necessarily set to 0.1% or more in view of ensuring a desirable level of corrosion resistance. On the other hand, the amount of addition exceeding 2% extremely widens a temperature range causing the ferrite phase transformation. The concentration of Al is therefore limited to 0.1% to 2%, both ends inclusive.
- Mn: Mn in the present invention functions mainly as improving the strength and as an austenite-forming element, and is added to suppress generation of coarse ferrite promoted by Cr and Al added in view of improving the corrosion resistance. More specifically, Cr and Al are ferrite-forming elements as well-known, wherein large amounts of addition of these elements may give a ferrite single phase structure over a range from solidification point to room temperature, without causing transformation, and may considerably degrade the toughness not only in the base metal, but also in the heat affected zone (HAZ). The present inventors made systematic experiments aiming at improving the toughness of the heat affected zone (HAZ) without causing the corrosion resistance, and found out that addition of Mn can avoid the problem. Specific conditions for limitation therefor will be described later, wherein Mn is necessarily added to as much as 0.1% or more, but the amount of addition exceeding 4% enhances the hardening property, so that the addition is limited up to 4%.
- N: The less N is contained, the more preferable, because a large amount of addition thereof to steel plate may lower the toughness of the base metal and the heat affected zone (HAZ), so that the upper limit of concentration thereof is set to 0.02%.
- P: The less P is contained, the more preferable, because abundance thereof lowers the toughness, so that the upper limit of concentration thereof is set to 0.03%. The concentration thereof ascribable to inevitable contamination is preferably minimized as possible.
- S: The less S is contained, the more preferable, too, because abundance thereof lowers pitting resistance, so that the upper limit of concentration thereof is set to 0.01%. Similarly to P, also the concentration of S ascribable to inevitable contamination is preferably minimized as possible.
- The present invention further allows addition of the elements below.
- Cu, Ni: Both of Cu and Ni exhibit effects of improving the strength, and of suppressing the ferrite generation. In particular, Ni has an effect of improving the toughness of the base metal and the heat affected zone (HAZ). Addition to as much as 0.1% or more is necessary for both of Cu and Ni in order to obtain these effects, wherein the amounts of addition of the both exceeding 4% enhances the hardenability and causes embrittlement. Both of the concentrations of Cu and Ni are therefore set to 0.1 to 4%.
- Mo: Mo added to as much as 0.01% or more to a steel added with Cr and Al exhibits an effect of suppressing generation and growth of pitting, without impairing the toughness of the base metal, whereas an amount of addition exceeding 1.0% not only saturates the effect but also degrades the toughness. The concentration of Mo is therefore set to 0.01% to 1.0%.
- Nb: Nb is an element improving the strength and toughness without impairing the corrosion resistance, wherein the effect thereof is recognizable at a concentration of as small as 0.005%, whereas the concentration exceeding 0.05% considerably degrades the toughness of the heat affected zone (HAZ). The concentration of Nb is therefore set to 0.005% to 0.05%.
- V: V is an element improving the strength without impairing the corrosion resistance, similar to Nb, wherein the effect thereof is recognizable at a concentration of as small as 0.01% or more, whereas a large amount of addition degrades the toughness as well-known. The upper limit of the V concentration is set to 0.1%.
- Ti: Ti is an element contributive to refinement of crystal grains at high temperatures through production of nitride, and can particularly improve the toughness of the heat affected zone (HAZ), without impairing the corrosion resistance. Both of refinement of the crystal' grains and improvement in the toughness are recognizable at a concentration of as small as 0.005% or more, whereas addition to as much as exceeding 0.03% adversely degrades the toughness of the base metal and the heat affected zone (HAZ), due to deposition of a large amount of carbide. The range of concentration is therefore set to 0.005% to 0.03%.
- Ca, Mg: Ca and Mg are elements capable of improving the corrosion resistance in a steel containing Cr and Al. Although much of the mechanism thereof remain unclear at present, it has been made clear that improvement in the corrosion resistance is recognizable at a concentration of as small as 5 ppm or more for the both, whereas the amount of addition exceeding 500 ppm not only saturates the effect of improving the corrosion resistance, but also tends to degrade the toughness. The concentrations of these elements are therefore set to 5 ppm to 500 ppm, both ends inclusive.
- REM: In the present invention, also appropriate addition of rare earth metals (REM) can improve the toughness of the base metal and the weld portion, without impairing the corrosion resistance. An amount of addition of 0.001% or more is necessary, whereas a large amount of addition degrades the toughness, so that the upper limit thereof is set to 0.1%.
- In the present invention, the parameter Tp expressed by the equation (1) is introduced, in order to improve the toughness of the weld portion, as one major object of the present invention.
where, %Cr, %Al, %C, %Mn, %Cu and %Ni are concentrations of Cr, Al, C, Mn, Cu and Ni (% by weight), respectively. - Fig. 1 shows results of measurement and observation of transformation point and generation behavior of coarse ferrite, obtained when materials composed of a 0.015%C-0.15%Si steel (P, S and N are within the ranges of the present invention) as a base, added with Mn, Cr and A1, and for some cases with Cu and/or Ni, were subjected to welding cycles. It is found from Fig. 1 that generation of the coarse ferrite phase is suppressed when value of the parameter Tp, plotted on the abscissa, reaches and exceeds 1150.
- The present inventors further investigated into relations between concentrations of the alloying elements and the toughness, for the purpose of ensuring a desirable level of toughness of the base metal, and found out that the toughness of the base metal can be evaluated based on the parameter Tc expressed by the equation (2).
- Fig. 2 shows, together with values of the parameter Tc, results of measurement of the toughness of a 0.02 to 0.05%C-0.25%Si steel as a base, added with Mn: 1.50 to 3.72%, Cr: 5.1 to 10.3% and Al: 0.8 to 1.5%, wherein a 20-mm-thick steel plate was manufactured by hot rolling, and test pieces were collected from a portion having a quarter thickness (5 mm) in the longitudinal direction. It is found from Fig. 2 that a range of the parameter Tc of 600 or more can ensure an absorption energy at -5°C (vE-5) of as desirable as 100 J or more. The present invention therefore sets the lower limit thereof to 600.
- As for corrosion-resistant steel of the present invention, the steel slab can be made by the ingot making/breaking down method, continuous casting method and the like. The steel slab may further be processed to give a steel plate by hot rolling, hot forging or the like, or may be hot-worked to give an arbitrary geometry corresponding to a user's need, such as steel pipes represented by seamless steel pipe, shape steels and the like. The hot working can be followed by air-cooling, for example. Tempering at a temperature not higher than Ac1 transformation point, aiming at further improving the strength, will never interfere the effects of the present invention.
- The corrosion-resistant steel according to the present invention is applicable, for example, to various corrosive environments, such as high-temperature and high-humidity corrosive environment, corrosive environment with dewing, aerial corrosive environment, corrosive environment with city water, corrosive environment with soil, corrosive environment with concrete, corrosive environment with seawater, and corrosive environments based on any combinations of them.
- Each of steels having compositions listed in Table 1 was melted and cast, hot rolled to give a 15-mm-thick steel plate, wherein some of them were further tempered, and subjected to the tests described below.
- All test pieces were collected from the center-thickness portion of the plate in the longitudinal direction.
- Evaluation of Toughness of Base Metal: Evaluation was carried out based on absorbed energy observed in the Charpy test at -5°C.
- Evaluation of Toughness of Heat Affected Zone (HAZ): Impact test of the heat affected zone (HAZ) after being subjected to the welding heat cycles was carried out. The maximum heating temperature and the cooling rate in the test were set to 1400°C and 15°C/s, respectively. The base metal was also subjected to the impact test. Transition temperatures were determined for the both, and ΔvTrs=([transition temperature of base metal]-[transition temperature after heat cycles]) was determined.
- 5-mm-thick corrosion test pieces were collected by cutting from a test steel plate, wherein some of them were provided with Zn-base coating (coating thickness: 15 to 25 µm), and then subjected to the test under conditions described below.
- Indoor Environment: The uncoated pieces were subjected to a one-hundred-day exposure test in a room with an air conditioner.
- Humid Environment: The test pieces were kept at -20°C for 2 hours, and then kept in an environment of 95% humidity at 25°C for 4 hours, and this cycle was repeated 13000 times. Size of rust spot was scored for all samples.
- Salt Damage Environment: The test pieces were exposed to a coastal splash zone for 17 months.
- Results of these tests are shown in Table 2. All of steels marked with A to K are those within the scope of the present invention, and every one of them showed a toughness of the base metal of 100 J or more , and a toughness of the heat affected zone (HAZ), evaluated in terms of ΔvTrs, of -15°C or more , proving only a small lowering in the toughness. As for corrosion resistance, only a slight rusting of as small as 2 mm or less was observed on some of the pieces, and all pieces showed desirable characteristics.
- On the contrary, all of the steels marked with L to U are those according to comparative examples out of scope of the present invention. More specifically, steels L, M and N, having the concentrations of C, Si and Mn, respectively, exceeding the upper limits specified by the present invention, showed almost desirable corrosion resistance, but showed considerable degradation in the toughness. The steel marked with L showed a toughness (ΔvTrs) of the heat affected zone (HAZ) of -40°C, indicating a large decrease. The steels marked with O and P, having amounts of addition of Cr and Al, which are elements contributive to improvement in the corrosion resistance, fallen below the lower limits, showed considerable decrease in the corrosion resistance. The steel marked with Q, having the Al concentration exceeding the upper limit, showed a desirable corrosion resistance, but was degraded in the toughness of the base metal. The steel marked with R, having Ni added as exceeding the upper limit, again showed a desirable corrosion resistance, but was poor in the toughness of the base metal. All of the steels marked with S, T and U have the concentrations of the individual element fallen within the ranges of the present invention, but have value(s) of the parameter(s) Tp and/or Tc out of the ranges of the present invention. More specifically, the steel marked with S is an example having only the parameter Tp fallen out of the range of the present invention, showing a degraded toughness of the heat affected zone (HAZ) of -55°C. The steel marked with T is an example having only the parameter Tc fallen out of the range of the present invention, showing a degraded toughness of the base metal of 83 J. The last steel marked with U is an example having both of the parameters Tp and Tc fallen out of the ranges of the present invention, showing degradation both in the toughness of the base metal and the heat affected zone (HAZ).
- The present invention can provide, at low costs, a steel excellent not only in the corrosion resistance in corrosive environment with dewing, and in other various corrosive environments such as indoor environment, aerial corrosive environment and corrosive environment with seawater, but also in the toughness of the heat affected zone (HAZ) which is important for weld structures, and can make a huge contribution to industrial development.
TABLE 1 (1) SYMBOL C Si Mn P S Cr Al N A 0.012 0.15 2.06 0.003 0.002 5.36 0.85 0.0045 WITHIN SCOPE OF THE PRESENT INVENTION B 0.015 0.26 2.53 0.001 0.001 6.32 1.15 0.0077 C 0.18 0.19 3.86 0.002 0.004 3.12 1.88 0.0056 D 0.012 0.46 2.02 0.001 0.003 10.58 0.18 0.0045 E 0.023 0.06 0.16 0.006 0.001 5.93 0.72 0.0054 F 0.027 1. 26 2. 23 0. 002 0.002 6.98 0. 32 0. 0085 G 0.038 0.28 2.88 0.002 0.001 4.89 1.13 0.0036 H 0.037 0.22 2.19 0.006 0.003 5.12 0.56 0.0136 I 0.019 0.87 2.38 0.003 0.002 4.44 1.02 0.0175 J 0.044 1.86 2.46 0.006 0.005 5.44 0.78 0.0056 K 0.025 0.55 2.04 0.004 0.002 4.22 1.65 0.0132 L 0.29 0.26 2.33 0.006 0.0004 6.12 0.78 0.0069 COMPARATIVE EXAMPLE M 0.035 2.86 2.12 0.003 0.0007 5.66 1.23 0.0065 N 0.18 0.75 4.26 0.002 0.001 3.02 1.66 0.0113 0 0.018 0.26 2.46 0.002 0.0008 2.10 1.23 0.0056 P 0.025 0. 39 2.12 0. 003 0.0008 8.23 0. 06 0. 0068 0 0.048 0.38 3.43 0.004 0.001 3.88 2.41 0.0098 R 0.023 0.23 0.58 0.001 0.0008 6.12 1.12 0.0075 S 0.026 0.28 3.35 0.003 0.001 6.28 1.35 0.0058 T 0.036 0.21 3.73 0.002 0.002 6.38 0.52 0.0068 U 0.045 0.63 3.68 0.006 0.003 6.88 1.71 0.0068 (mass%) TABLE 1 (2) SYMBOL Cu Ni Mo T Nb V Ca Mg REM Tp Tc A 1249 729 WITHIN SCOPE OF THE PRESENT INVENTION B 0.22 1160 700 C 0.59 1236 618 D 0.12 1262 601 E 1.26 1344 790 F 0.042 1359 644 G 0.015 1224 685 H 0.22 0.004 1381 680 I 0.86 0.96 0.028 1400 676 J 0.001 1295 681 K 3.68 0.0036 1458 606 L 0.15 1391 607 COMPARATIVE EXAMPLE M 1.82 0.001 1338 643 N 0.0012 1252 603 0 0.016 1267 775 P 0.0036 1386 614 Q 2.23 0.002 1153 633 R 0.12 4.52 1593 606 S 0.012 1124 648 T 0.012 1376 547 U 0.75 0.011 1101 594 (mass%) TABLE 2 STEEL MANUFACTURING METHOD OF BASE METAL TOUGHNESS OF BASE METAL vE-5 (J) THOUGHNESS OF WELDING-HEAT-AFFECTED PORTION CORROSION RESISTANCE (TOUGHNE OF BASE METAL) - (TOUGHNESS OF WELD PORTION) ΔvTrs (°C) INDOOR ENVIROMENT HUMID ENVIRMENT SALT DAMAGE ENVIROMENT NO COATING NO COATING Zn-BASE COATING Zn-BASE COATING WITHIN SCOPE OF THE PRESENT INVENTION A AS-ROLLED 223 -10 ⊚ ⊚ ⊚ ○ B AS-ROLLED 253 -15 ⊚ ⊚ ⊚ ⊚ C AS-ROLLED 132 0 ○ ⊚ ○ ⊚ D AS-ROLLED + TEMPERED 122 -5 ⊚ ⊚ ⊚ ⊚ E AS-ROLLED 201 -10 ⊚ ⊚ ⊚ ○ F AS-ROLLED 248 -5 ⊚ ○ ⊚ ⊚ G AS-ROLLED 263 -5 ⊚ ○ ⊚ ○ H AS-ROLLED 230 -15 ○ ○ ⊚ ⊚ I AS-ROLLED 213 -10 ⊚ ⊚ ⊚ ⊚ J AS-ROLLED + TEMPERED 183 -15 ○ ○ ⊚ ○ K AS-ROLLED 198 -10 ⊚ ⊚ ⊚ ⊚ COMPARATIVE EXAMPLE L AS-ROLLED 43 -40 ⊚ ○ ⊚ Δ M AS-ROLLED 65 -15 ⊚ ⊚ ⊚ ⊚ N AS-ROLLED + TEMPERED 58 -15 ⊚ ○ ○ ⊚ O AS-ROLLED 216 -15 ▲ × Δ × P AS-ROLLED 263 -15 Δ × Δ × Q AS-ROLLED + TEMPERED 93 -20 ⊚ ⊚ ⊚ ⊚ R AS-ROLLED 83 -10 ⊚ ⊚ ⊚ ⊚ S AS-ROLLED 213 -55 ⊚ ⊚ ⊚ ⊚ T AS-ROLLED 83 -15 ⊚ ⊚ ⊚ Δ U AS-ROLLED 76 -50 ⊚ ⊚ ⊚ ⊚ ⊚ : NO RUSTING
○ : RUST OF 2mm OR SMALLER
Δ : RUST OF 5mm OR SMALLER
▲ : RUST OF 10mm OR SMALLER
× : RUSTED ALMOST OVER ENTIRE SURFACE
Claims (6)
- A corrosion-resistant steel excellent in toughness of a base metal and a weld portion, containing, in % by weight:C: 0.2% or less; ,Si: 0.01 to 2.0%;Mn: 0.1 to 4%;P: 0.03% or less;S: 0.01% or less;Cr: 3 to 11%;Al: 0.1 to 2%; andN: 0.02%, andhaving values of 1150 or more, and 600 or more respectively for Tp and Tc expressed by the equations below using concentrations of Cr, Al, C, Mn, Cu and Ni respectively given as %Cr, %Al, %C, %Mn, %Cu and %Ni.
- The corrosion-resistant steel excellent in toughness of a base metal and a weld portion according to claim 1, further containing, in % by weight, any one of, or two or more elements selected from the group consisting of:Cu: 0.1 to 4%;Ni: 0.1 to 4%;Mo: 0.01 to 1%;V: 0.01 to 0.1%;Nb: 0.005 to 0.050%;Ti: 0.005 to 0.03%;Ca: 0.0005 to 0.05%;Mg: 0.0005 to 0.05%; andREM: 0.001 to 0.1%.
- A method of manufacturing a corrosion-resistant steel excellent in toughness of a base metal and a weld portion, comprising the steps of:heating a steel slab;the steel slab containing, in % by weight:C: 0.2% or less;Si: 0.01 to 2.0%;Mn: 0.1 to 4%;P: 0.03% or less;S: 0.01% or less;Cr: 3 to 11%;Al: 0.1 to 2%; andN: 0.02%, andhaving values of 1150 or more , and 600 or more respectively for Tp and Tc expressed by the equations below using concentrations of Cr, Al, C, Mn, Cu and Ni respectively given as %Cr, %Al, %C, %Mn, %Cu and %Ni,
forming a steel plate by hot rolling of the steel slab; and
cooling the steel plate by air. - The method of manufacturing a corrosion-resistant steel excellent in toughness of a base metal and a weld portion according to claim 3, wherein the steel slab further contains, in % by weight, any one of, or two or more elements selected from the group consisting of:Cu: 0.1 to 4%;Ni: 0.1 to 4%;Mo: 0.01 to 1%;V: 0.01 to 0.1%;Nb: 0.005 to 0.050%;Ti: 0.005 to 0.03%;Ca: 0.0005 to 0.05%;Mg: 0.0005 to 0.05%; andREM: 0.001 to 0.1%.
- The method of manufacturing a corrosion-resistant steel excellent in toughness of a base metal and a weld portion according to claim 3, further comprising, after said step of cooling the steel plate by air, tempering the steel plate at a temperature of Ac1 transformation point or below.
- The method of manufacturing a corrosion-resistant steel excellent in toughness of a base metal and a weld portion according to claim 4, further comprising, after said step of cooling the steel plate by air, tempering the steel plate at a temperature of Ac1 transformation point or below.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004072438A JP4441295B2 (en) | 2004-03-15 | 2004-03-15 | Manufacturing method of high strength steel for welding and high strength steel for welding with excellent corrosion resistance and machinability |
PCT/JP2004/006663 WO2005087964A1 (en) | 2004-03-15 | 2004-05-12 | Corrosion-resistant steel excellent in toughness of base metal and weld and process for producing the same |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1734142A1 true EP1734142A1 (en) | 2006-12-20 |
EP1734142A4 EP1734142A4 (en) | 2007-04-25 |
Family
ID=34975601
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP04732471A Withdrawn EP1734142A4 (en) | 2004-03-15 | 2004-05-12 | Corrosion-resistant steel excellent in toughness of base metal and weld and process for producing the same |
Country Status (7)
Country | Link |
---|---|
US (1) | US20080274008A1 (en) |
EP (1) | EP1734142A4 (en) |
JP (1) | JP4441295B2 (en) |
KR (1) | KR100831115B1 (en) |
CN (1) | CN100562597C (en) |
CA (1) | CA2559843C (en) |
WO (1) | WO2005087964A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
RU2625510C1 (en) * | 2016-11-17 | 2017-07-14 | Федеральное Государственное Унитарное Предприятие "Центральный научно-исследовательский институт черной металлургии им. И.П. Бардина" (ФГУП "ЦНИИчермет им. И.П. Бардина") | Method of producing high-strength corrosion-resistant hot-rolled steel |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2010113828A1 (en) * | 2009-03-30 | 2010-10-07 | 新日本製鐵株式会社 | Corrosion-resistant steel for use in chimney or flue of natural gas combustion or liquefied petroleum gas combustion plant |
US20130202908A1 (en) * | 2012-02-08 | 2013-08-08 | Grzegorz Jan Kusinski | Equipment for use in corrosive environments and methods for forming thereof |
JP5974678B2 (en) * | 2012-06-29 | 2016-08-23 | 新日鐵住金株式会社 | Steel member and method for manufacturing steel member |
CN102994915B (en) * | 2012-11-20 | 2015-09-02 | 江苏高博智融科技有限公司 | A kind of corrosion-resistant stainless steel metal |
CN103834871B (en) * | 2014-03-19 | 2017-01-18 | 武汉钢铁(集团)公司 | 500MPa-level corrosion-resistant Cr-contained reinforcing steel bar and rolling process thereof |
CN103849820B (en) * | 2014-03-19 | 2017-01-04 | 武汉钢铁(集团)公司 | The rolling mill practice of high-strength corrosion-resisting Li-adding Al alloy muscle |
JP6405910B2 (en) * | 2014-11-10 | 2018-10-17 | 新日鐵住金株式会社 | Corrosion resistant steel |
JP6107892B2 (en) * | 2015-06-29 | 2017-04-05 | 新日鐵住金株式会社 | Steel member and method for manufacturing steel member |
JP6992499B2 (en) * | 2017-12-26 | 2022-01-13 | 日本製鉄株式会社 | Steel material |
CN111349847B (en) * | 2018-12-24 | 2022-03-18 | 宝山钢铁股份有限公司 | Seawater corrosion resistant steel and manufacturing method thereof |
CN110551945B (en) * | 2019-10-10 | 2020-04-14 | 阳春新钢铁有限责任公司 | Optimization method of hot-rolled plain steel bar production process |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05279791A (en) * | 1992-02-07 | 1993-10-26 | Nippon Steel Corp | Steel excellent in corrosion resistance |
JPH06179949A (en) * | 1992-12-11 | 1994-06-28 | Nippon Steel Corp | Steel excellent in corrosion resistance and workability |
JPH06212256A (en) * | 1993-01-11 | 1994-08-02 | Nippon Steel Corp | Production of steel and steel pipe excellent in corrosion resistance |
JPH073388A (en) * | 1993-06-18 | 1995-01-06 | Nippon Steel Corp | Steel excellent in corrosion resistance |
JPH10237600A (en) * | 1997-02-27 | 1998-09-08 | Sumitomo Metal Ind Ltd | Ferritic heat resistant steel excellent in high temperature weld cracking resistance and toughness in heat-affected zone |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA2151513C (en) * | 1992-12-11 | 1999-11-16 | Kenji Kato | Steel excellent in corrosion resistance and processability |
JP2002363704A (en) * | 2001-06-12 | 2002-12-18 | Nippon Steel Corp | Corrosion resistant steel having excellent toughness in base material and heat affected zone |
JP2004162121A (en) * | 2002-11-13 | 2004-06-10 | Nippon Steel Corp | High strength non-heat treated steel sheet with excellent weld heat affected zone toughness/corrosion resistance |
JP3845366B2 (en) * | 2002-11-13 | 2006-11-15 | 新日本製鐵株式会社 | Corrosion resistant steel with excellent weld heat affected zone toughness |
-
2004
- 2004-03-15 JP JP2004072438A patent/JP4441295B2/en not_active Expired - Lifetime
- 2004-05-12 CA CA2559843A patent/CA2559843C/en not_active Expired - Fee Related
- 2004-05-12 EP EP04732471A patent/EP1734142A4/en not_active Withdrawn
- 2004-05-12 CN CNB2004800424588A patent/CN100562597C/en not_active Expired - Lifetime
- 2004-05-12 US US10/592,836 patent/US20080274008A1/en not_active Abandoned
- 2004-05-12 WO PCT/JP2004/006663 patent/WO2005087964A1/en active Application Filing
- 2004-05-12 KR KR1020067018823A patent/KR100831115B1/en active IP Right Grant
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05279791A (en) * | 1992-02-07 | 1993-10-26 | Nippon Steel Corp | Steel excellent in corrosion resistance |
JPH06179949A (en) * | 1992-12-11 | 1994-06-28 | Nippon Steel Corp | Steel excellent in corrosion resistance and workability |
JPH06212256A (en) * | 1993-01-11 | 1994-08-02 | Nippon Steel Corp | Production of steel and steel pipe excellent in corrosion resistance |
JPH073388A (en) * | 1993-06-18 | 1995-01-06 | Nippon Steel Corp | Steel excellent in corrosion resistance |
JPH10237600A (en) * | 1997-02-27 | 1998-09-08 | Sumitomo Metal Ind Ltd | Ferritic heat resistant steel excellent in high temperature weld cracking resistance and toughness in heat-affected zone |
Non-Patent Citations (1)
Title |
---|
See also references of WO2005087964A1 * |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
RU2625510C1 (en) * | 2016-11-17 | 2017-07-14 | Федеральное Государственное Унитарное Предприятие "Центральный научно-исследовательский институт черной металлургии им. И.П. Бардина" (ФГУП "ЦНИИчермет им. И.П. Бардина") | Method of producing high-strength corrosion-resistant hot-rolled steel |
Also Published As
Publication number | Publication date |
---|---|
JP4441295B2 (en) | 2010-03-31 |
CA2559843C (en) | 2011-10-11 |
CN1926256A (en) | 2007-03-07 |
EP1734142A4 (en) | 2007-04-25 |
CA2559843A1 (en) | 2005-09-22 |
KR20060125898A (en) | 2006-12-06 |
WO2005087964A1 (en) | 2005-09-22 |
JP2005256135A (en) | 2005-09-22 |
KR100831115B1 (en) | 2008-05-20 |
CN100562597C (en) | 2009-11-25 |
US20080274008A1 (en) | 2008-11-06 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
KR101339484B1 (en) | High-strength stainless steel pipe | |
EP0750687B2 (en) | High hardness martensitic stainless steel with good pitting corrosion resistance | |
EP0545753B1 (en) | Duplex stainless steel having improved strength and corrosion resistance | |
EP1592820B1 (en) | Austenitic stainless steels including molybdenum | |
EP2562284B1 (en) | Cr-CONTAINING STEEL PIPE FOR LINE PIPE AND HAVING EXCELLENT INTERGRANULAR STRESS CORROSION CRACKING RESISTANCE AT WELDING-HEAT-AFFECTED PORTION | |
EP1734142A1 (en) | Corrosion-resistant steel excellent in toughness of base metal and weld and process for producing the same | |
JP7329984B2 (en) | stainless steel | |
WO1999009231A1 (en) | Austenitic stainless steel excellent in resistance to sulfuric acid corrosion and workability | |
JP5692002B2 (en) | High-tensile steel plate with excellent weldability and manufacturing method thereof | |
JP2001059141A (en) | Austenitic stainless steel and automotive exhaust system paprts | |
JP3845366B2 (en) | Corrosion resistant steel with excellent weld heat affected zone toughness | |
KR102597735B1 (en) | Ferritic stainless steel sheet and manufacturing method thereof | |
EP1026273B1 (en) | Martensite stainless steel of high corrosion resistance | |
JP3966136B2 (en) | Stainless steel pipe for line pipe with excellent corrosion resistance | |
JP4317517B2 (en) | High corrosion resistance hot rolled steel sheet with excellent workability and weld heat affected zone toughness and its manufacturing method | |
US4808371A (en) | Exterior protective member made of austenitic stainless steel for a sheathing heater element | |
US20100096048A1 (en) | 655 mpa grade martensitic stainless steel having high toughness and method for manufacturing the same | |
JP2002363704A (en) | Corrosion resistant steel having excellent toughness in base material and heat affected zone | |
JP3973456B2 (en) | Austenitic stainless steel with excellent high temperature salt damage corrosion resistance | |
JP3846218B2 (en) | Structural steel with excellent weather resistance | |
JP3542209B2 (en) | Welded structural steel with excellent weather resistance | |
JP5089103B2 (en) | Stainless steel with excellent corrosion resistance | |
JP2000290754A (en) | High corrosion resistance clad steel and chimney for coal fired power plant | |
KR102255119B1 (en) | LOW-Cr FERRITIC STAINLESS STEEL WITH IMPROVED EXPANABILITY AND MANUFACTURING METHOD THEREOF | |
JP2004162121A (en) | High strength non-heat treated steel sheet with excellent weld heat affected zone toughness/corrosion resistance |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20061005 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB |
|
A4 | Supplementary search report drawn up and despatched |
Effective date: 20070328 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: C22C 38/00 20060101AFI20050928BHEP |
|
DAX | Request for extension of the european patent (deleted) | ||
RBV | Designated contracting states (corrected) |
Designated state(s): DE FR GB |
|
17Q | First examination report despatched |
Effective date: 20100921 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20120322 |