CN102363868A - Pipeline steel and production method thereof - Google Patents
Pipeline steel and production method thereof Download PDFInfo
- Publication number
- CN102363868A CN102363868A CN2011103378282A CN201110337828A CN102363868A CN 102363868 A CN102363868 A CN 102363868A CN 2011103378282 A CN2011103378282 A CN 2011103378282A CN 201110337828 A CN201110337828 A CN 201110337828A CN 102363868 A CN102363868 A CN 102363868A
- Authority
- CN
- China
- Prior art keywords
- steel
- controlled
- slab
- pipe line
- stove
- 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.)
- Pending
Links
Landscapes
- Heat Treatment Of Steel (AREA)
Abstract
The invention discloses a pipeline steel and a production method thereof. The pipeline steel comprises the chemical components, by mass, 0.04-0.12 parts of C, equal to or less than 0.40% of Si, 0.8-1.6% of Mn, 0.10-0.40% of Cr, 0.02-0.08% of Nb, 0.010-0.025% of Ti, equal to or less than 0.025% of P, equal to or less than 0.015% of S, 0.015-0.060% of Al, and the balance Fe and advoidless impurity elements. The invention also discloses the production method of the pipeline steel. The pipeline steel is produced according to the chemical components and the production method provided by the invention and is obtained through rolling by cooperating a small amount of a chromium alloyed component design with a TMCP technology, so problems of large yield ratio control difficulty of thin specification pipelines are avoided, and the alloy cost is reduced to some degrees by removing a precious metal element V.
Description
Technical field
The invention belongs to low yield strength ratio pipe line steel production technical field, be specifically related to a kind of pipe line steel and working method thereof.
Background technology
Yield tensile ratio is the important indicator of pipe line steel security, and low yield strength ratio means and is difficult for more when steel pipe deforms under external force breaking.But yield tensile ratio can fluctuate with the variation of tube-making process from steel plate to the process of processing steel pipe.Therefore, steel pipe's production enterprise meets the requirements for the yield tensile ratio that guarantees steel pipe, all raw-material yield tensile ratio has been proposed strict more requirement.This is the difficult problem that must solve during pipe line steel is produced in enormous quantities.
The height of yield tensile ratio is determined by ys and two factors of tensile strength jointly.The high-grade pipe line steel of producing in the present world wide is generally through adding microalloy element and TMCP (controlled rolling and controlled cooling) technology raising matrix strengths such as Nb, V, Ti.Nb, V, Ti microalloy element mainly improve the intensity of steel plate, wherein precipitation strength effect dominates status through mechanisms of action such as precipitation strength and refined crystalline strengthenings.TMCP technology cooperates with microalloy element, the maximum potential of performance microalloy element, especially precipitation strength effect.The final cooling temperature of therefore general microalloy steel for pipeline guarantees the effect of precipitation strength between 550～650 ℃.And precipitation strength will be significantly higher than the contribution to tensile strength to the raising of ys.Therefore the net result of precipitation strength is to cause the yield tensile ratio of pipe line steel to raise.
And below 12m, approach in the production of specification pipe line steel, this problem is particularly outstanding.On-the-spot practical production experience shows, the pipeline steel plate of identical component, different thickness, and the ys of thin specification steel plate and yield tensile ratio are apparently higher than thick steel plates.This mainly is because the deflection of thin specification is bigger, and cooling rate is higher, controlled rolling and controlled cooling better effects if, so more fully the causing of microalloy highly malleablized effect performance.In the actual production, the yield tensile ratio of thin specification pipeline steel plate often exceeds standard easily.Therefore, the control of yield tensile ratio becomes a big bottleneck of producing thin specification microalloy steel for pipeline in enormous quantities.
Simultaneously, in existing publication, in the majority to thick steel plates, the effect in relatively thin pipe line steel is produced is very undesirable.Such as publication number is the patent " a kind of working method of low yield strength ratio microalloy steel for pipeline hot-rolled coil " of CN101979166A, batches the production that realizes the low yield strength ratio pipe line steel through two stages control cold-peace low temperature.Its weak point is: thin specification pipe line steel is when being cooled to below 500 ℃, and serious shape wave promptly appears in steel band on rollgang, cause and batch difficulty and can't produce steel pipe.Publication number is the patent " a kind of working method of controlling the line steel hot rolling flat plate yield tensile ratio " of CN1978082A, obtains lower yield tensile ratio through control hot rolling Heating temperature, roughing temperature range, final rolling temperature interval, percentage pass reduction and cooling rate.Its weak point is: this method is also inapplicable for the steel plate of the thin specification of this type of roll bending, and this technology can cause the roll bending yield tensile ratio 0.88～0.96 fluctuation.
Summary of the invention
The objective of the invention is to, overcome existing thin specification pipe line steel production process yield tensile ratio and overcome the big problem of difficulty, low pipe line steel of a kind of yield tensile ratio and working method thereof are provided.
A kind of pipe line steel provided by the invention, its chemical ingredients mass percent is C:0.04～0.12%; Si≤0.40%; Mn:0.8～1.6%; Cr:0.10～0.40%; Nb:0.02～0.08%; Ti:0.010～0.025%; P≤0.025%; S≤0.015%; Al:0.015～0.060%; Other is iron and unavoidable impurities element.
A kind of method of producing above-mentioned pipe line steel is provided according to another aspect of the present invention, comprises:
With molten iron through pre-treatment after; Obtain the molten steel of required composition again through converter smelting, LF stove or the refining of LF+RH stove; When said molten iron passes through converter smelting, LF stove or the refining of LF+RH stove; Adopt CrFe adjustment Cr constituent content, the Cr constituent content is controlled in 0.10～0.40% scope in the molten steel thereby make;
Said molten steel is obtained slab through continuous casting;
After said slab heated through process furnace, obtain hot rolled strip through roughing, finish rolling again;
After said hot rolled strip carried out laminar flow cooling, utilize reeling machine to coil into hot-rolled sheet coil again;
Said hot-rolled sheet coil is directly processed finished product or after opening straight snips to be cut into steel plate, processed finished product again.
Further, when said slab was heated through process furnace, the heating zone temperature was controlled at 1180～1280 ℃, and the soaking zone temperature is controlled at 1160～1260 ℃, and tapping temperature is controlled at 1160～1250 ℃, is controlled at 2.5～5.5h heat-up time.
Further, through roughing the time, require rolling slab after the said heating in the perfect recrystallization district.
Further, through finish rolling the time, require rolling slab after the said roughing in the non-recrystallization district.
Further, said finishing temperature is controlled at 800～860 ℃.
Further, said hot rolled strip is carried out laminar flow cooling back final cooling temperature and be controlled at 520～640 ℃.
A kind of pipe line steel provided by the invention and working method thereof; Adopt the composition design of a small amount of Cr alloying to cooperate TMCP technology rolling, avoided the big problem of thin specification pipe line steel yield tensile ratio control difficulty, simultaneously; Owing to removed precious metal element V, can reduce cost of alloy to a certain extent.
Embodiment
The object of the present invention is to provide a kind of pipe line steel and working method thereof, be used to make thin specification low yield strength ratio pipeline steel tube.Through adding the composition design of a small amount of Cr element, cooperate two conventional stage controlled rolling+cooling control technologies, in stable realization low yield strength ratio, guarantee the quality such as plate shape of steel band, be fit to very much stable mass production.
A kind of pipe line steel provided by the invention, its chemical ingredients (heat analysis) mass percent is: C:0.04～0.12%; Si≤0.40%; Mn:0.8～1.6%; Cr:0.10～0.40%; Nb:0.02～0.08%; Ti:0.010～0.025%; P≤0.025%; S≤0.015%; Al:0.015～0.060%; Other is iron and unavoidable impurities element.
Acting as of each main alloy element wherein:
C：0.04～0.12％。The C element is the main solution strengthening element of steel, and combines to form precipitation hardened steel matrix with the steel grade microalloy element.But the C too high levels will worsen tissue, welding property and the impact property of steel.Therefore the present invention is controlled at lower scope with C content, has both brought into play its strengthening effect, does not reduce its toughness properties and use properties again.
Mn：0.8～1.6％。The Mn element is an austenite former, reduces the austenite-ferrite transformation temperature, and thinning microstructure improves toughness, also has significantly solution strengthening effect, content to cross the low toughness and tenacity that can't guarantee steel simultaneously.But too high levels will cause tangible segregation and tissue deterioration, influence toughness properties.
Cr：0.10～0.40％。The Cr element is a ferrite former, is lower than at 5% o'clock at the Cr constituent content and reduces austenite-ferrite transformation temperature, thinning microstructure.The Cr element also improves the hardening capacity of steel, under identical cooling conditions, obtains the low temperature tissue more easily.Simultaneously, the Cr element can also form the carbide precipitated phase with the C element.Because the Cr element is unfavorable to welding property to the raising of hardening capacity, the content that therefore requires Cr element in the steel is below 0.40%.
Nb：0.02～0.08％。Niobium is the most important most typical microalloy element of generally acknowledging at present, and the institute of microalloy element in steel plays an important role and all possess.The most important effect of niobium is to stop the austenitic recrystallize of deformation, obtains the extremely very high flats austenite crystal of extended deformation energy storage, and after γ → α phase transformation subsequently, obtains very tiny ferrite crystal grain; Also can significantly promote deformation induced ferrite transformation simultaneously, and because the Nb that deposition is separated out in ferritic (C, N) prevention grain growth, and obtain more tiny ferrite crystal grain.
Ti：0.010～0.025％。Ti is strong nitride forming element, and the effective pinning austenite grain boundary of TiN under the high temperature suppresses AUSTENITE GRAIN COARSENING under the high temperature.Cross low Ti and cause the TiN solid solubility temperature low excessively, can't effectively stop the austenite alligatoring.Too high Ti causes TiN in molten steel, to separate out and alligatoring, worsens the impelling strength of steel.
The present invention provides a kind of method of producing above-mentioned pipe line steel on the other hand, comprising:
Step S1: with molten iron through pre-treatment after, obtain the molten steel of required composition again through converter smelting, LF stove or the refining of LF+RH stove, adjustment Cr constituent content during through converter smelting, LF stove or the refining of LF+RH stove with said molten iron; When molten iron is passed through converter smelting, LF stove or LF+RH refining, adopt the content of CrFe adjustment Cr element, thereby the content of Cr element in the molten steel is controlled in 0.10～0.40% scope.
Step S2: molten steel is obtained slab through continuous casting;
Step S3: slab is heated through process furnace; When slab was heated through process furnace, the heating zone temperature was controlled at 1180～1280 ℃, and the soaking zone temperature is controlled at 1160～1260 ℃, and tapping temperature is controlled at 1160～1250 ℃, is controlled at 2.5～5.5h heat-up time.
Step S4: the slab after will heating obtains hot rolled strip through roughing, finish rolling, and hot rolled strip is carried out utilizing reeling machine to coil into hot-rolled sheet coil again after the laminar flow cooling.During with the roughing of the process of the slab after the heating, require rolling in the perfect recrystallization district.When the finish rolling, require rollingly in the non-recrystallization district, finishing temperature is controlled at 800～860 ℃.Hot rolled strip is carried out laminar flow cooling back final cooling temperature be controlled at 520～640 ℃.
Step S5: hot-rolled sheet coil is directly processed finished product or after opening straight snips to be cut into steel plate, processed finished product again.
Can make steel reach HS and H.T. through TMCP technology, be to realize through cold phase-change organization's control and the phase-change organization's refinement that combines of controlled rolling refine austenite crystal grain, processing strain and control afterwards basically.It can not only improve intensity and toughness, and can reduce the addition of alloying element.
Because TMCP technology is not being added too much alloying element; Do not need to produce under the condition of complicated subsequent heat treatment the steel of high-intensity high-tenacity yet; Be considered to one and practice thrift alloy and the energy, environmentally friendly technology also; So since the exploitation eighties in 20th century, become the indispensable technology of low cost prodn high-performance steel iron material.Along with the requirement of market to the TMCP steel improves constantly, also constantly development in application of TMCP technology itself.TMCP research at present focus on controlled chilling, especially quicken the cooling aspect.
The purpose of accelerated cooling process mainly is when improving speed of cooling as far as possible, to prevent the steel plate deformed that produces in the process of cooling, and its key is to guarantee the temperature homogeneity of steel plate.
The method of a kind of production flow line steel provided by the invention adopts the composition design of a small amount of Cr alloying to cooperate TMCP technology rolling; Avoided the big problem of thin specification pipe line steel yield tensile ratio control difficulty, for the stable production in enormous quantities of such steel provides feasible technical scheme.Simultaneously, owing to removed precious metal element V, can reduce cost of alloy to a certain extent.
Embodiment
Table 1 is the chemical ingredients of test steel among the embodiment, and its hot rolling technology by regulation is rolled into pipeline steel plate or volume, and mechanical property is seen table 2.
Can find out by table 2; Adopt composition of the present invention and technology; The ys of the test steel of producing is all more than 485MPa; Still can meet the requirement of X60 and X65 pipe line steel after the Bauschinger effect behind the consideration tubulation, and yield tensile ratio all satisfied conventional require (general requirement is not more than 0.90), stable batch process can be guaranteed.
The chemical ingredients of test steel among table 1 embodiment, wt.%
| Numbering | C | Si | Mn | P | S | Cr | Nb | Ti | Alt |
| A | 0.087 | 0.11 | 1.33 | 0.009 | 0.002 | 0.14 | 0.030 | 0.017 | 0.039 |
| B | 0.078 | 0.16 | 1.42 | 0.014 | 0.002 | 0.15 | 0.029 | 0.015 | 0.042 |
| C | 0.094 | 0.10 | 1.28 | 0.010 | 0.001 | 0.14 | 0.027 | 0.014 | 0.036 |
The mechanical property of test steel among table 2 embodiment
The comparative example
The chemical ingredients of test steel among table 3 comparative example, wt.%
| Numbering | C | Si | Mn | P | S | Cr | Nb | V | Ti | Alt |
| A | 0.095 | 0.10 | 1.20 | 0.014 | 0.002 | 0.02 | 0.028 | 0.024 | 0.015 | 0.039 |
| B | 0.086 | 0.18 | 1.34 | 0.011 | 0.001 | 0.02 | 0.029 | 0.025 | 0.016 | 0.041 |
| C | 0.084 | 0.12 | 1.21 | 0.009 | 0.001 | 0.01 | 0.029 | 0.027 | 0.013 | 0.039 |
The mechanical property of test steel among table 4 comparative example
Can find out that from the Comparative Examples of table 3～4 Comparative Examples and difference of the present invention are: Comparative Examples contains the V element about 0.025%, does not contain Cr; And the present invention contains the Cr about 0.15%, does not contain V element.Under the identical hot rolling technology condition with the thickness specification of basically identical under, the ys of Comparative Examples is a little more than the present invention, and tensile strength is a little less than the present invention, this is the lower reason of steel plate yield tensile ratio of the present invention.The yield tensile ratio of Comparative Examples can't satisfy the requirement (general requirement is not higher than 0.90) of common pipe line steel apparently higher than this patent.
The foregoing description is a preferred implementation of the present invention; But embodiment of the present invention is not restricted to the described embodiments; Other any do not deviate from change, the modification done under spirit of the present invention and the principle, substitutes, combination, simplify; All should be the substitute mode of equivalence, be included within protection scope of the present invention.
Claims (7)
1. a pipe line steel is characterized in that, its chemical ingredients mass percent is:
C:0.04 ~ 0.12%; Si≤0.40%; Mn:0.8 ~ 1.6%; Cr:0.10 ~ 0.40%; Nb:0.02 ~ 0.08%; Ti:0.010 ~ 0.025%; P≤0.025%; S≤0.015%; Al:0.015 ~ 0.060%; Other is iron and unavoidable impurities element.
2. produce pipe line steel method as claimed in claim 1 for one kind, it is characterized in that, comprising:
With molten iron through pre-treatment after; Obtain the molten steel of required composition again through converter smelting, LF stove or the refining of LF+RH stove; When said molten iron passes through converter smelting, LF stove or the refining of LF+RH stove; Adopt CrFe adjustment Cr constituent content, the Cr constituent content is controlled in 0.10 ~ 0.40% scope in the molten steel thereby make;
Said molten steel is obtained slab through continuous casting;
After said slab heated through process furnace, obtain hot rolled strip through roughing, finish rolling again;
After said hot rolled strip carried out laminar flow cooling, utilize reeling machine to coil into hot-rolled sheet coil again;
Said hot-rolled sheet coil is directly processed finished product or after opening straight snips to be cut into steel plate, processed finished product again.
3. method as claimed in claim 2 is characterized in that:
When said slab was heated through process furnace, the heating zone temperature was controlled at 1180 ~ 1280 ℃, and the soaking zone temperature is controlled at 1160 ~ 1260 ℃, and tapping temperature is controlled at 1160 ~ 1250 ℃, is controlled at 2.5 ~ 5.5h heat-up time.
4. method as claimed in claim 2 is characterized in that:
Through roughing the time, require rolling slab after the said heating in the perfect recrystallization district.
5. method as claimed in claim 2 is characterized in that:
Through finish rolling the time, require rolling slab after the said roughing in the non-recrystallization district.
6. method as claimed in claim 2 is characterized in that:
Said finishing temperature is controlled at 800 ~ 860 ℃.
7. the working method of a kind of pipe line steel as claimed in claim 2 is characterized in that:
Said hot rolled strip is carried out laminar flow cooling back final cooling temperature be controlled at 520 ~ 640 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011103378282A CN102363868A (en) | 2011-10-31 | 2011-10-31 | Pipeline steel and production method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011103378282A CN102363868A (en) | 2011-10-31 | 2011-10-31 | Pipeline steel and production method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102363868A true CN102363868A (en) | 2012-02-29 |
Family
ID=45690461
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011103378282A Pending CN102363868A (en) | 2011-10-31 | 2011-10-31 | Pipeline steel and production method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102363868A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103667875A (en) * | 2013-08-15 | 2014-03-26 | 首钢京唐钢铁联合有限责任公司 | Preparation method of low-carbon acid-resistant pipeline steel |
| CN105568143A (en) * | 2016-03-15 | 2016-05-11 | 首钢总公司 | Thick pipeline steel hot continuous rolling steel belt easy to coil and excellent in low-temperature performance and manufacturing method thereof |
| CN106811699A (en) * | 2015-12-02 | 2017-06-09 | 鞍钢股份有限公司 | A kind of ERW X65 hot-rolled coils and its manufacture method |
| WO2021017521A1 (en) * | 2019-08-01 | 2021-02-04 | 江阴兴澄特种钢铁有限公司 | Low yield-to-tensile ratio thin specification pipeline steel manufacturing method |
| CN115125432A (en) * | 2022-06-13 | 2022-09-30 | 本钢板材股份有限公司 | Manufacturing method of 650 MPa-grade high-strength and light-weight steel for automobile spoke |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101307413A (en) * | 2007-05-17 | 2008-11-19 | 首钢总公司 | Microalloying steel for ultra-high-strength sucker rod |
| CN101768703A (en) * | 2010-01-26 | 2010-07-07 | 东北大学 | Grade X80 pipe line steel with low yield ratio and manufacturing method thereof |
| CN101994061A (en) * | 2010-11-26 | 2011-03-30 | 首钢总公司 | Steel for petroleum casing pipe and manufacture method thereof |
-
2011
- 2011-10-31 CN CN2011103378282A patent/CN102363868A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101307413A (en) * | 2007-05-17 | 2008-11-19 | 首钢总公司 | Microalloying steel for ultra-high-strength sucker rod |
| CN101768703A (en) * | 2010-01-26 | 2010-07-07 | 东北大学 | Grade X80 pipe line steel with low yield ratio and manufacturing method thereof |
| CN101994061A (en) * | 2010-11-26 | 2011-03-30 | 首钢总公司 | Steel for petroleum casing pipe and manufacture method thereof |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103667875A (en) * | 2013-08-15 | 2014-03-26 | 首钢京唐钢铁联合有限责任公司 | Preparation method of low-carbon acid-resistant pipeline steel |
| CN103667875B (en) * | 2013-08-15 | 2016-12-28 | 首钢京唐钢铁联合有限责任公司 | The preparation method of low-carbon acid-resistant pipeline steel |
| CN106811699A (en) * | 2015-12-02 | 2017-06-09 | 鞍钢股份有限公司 | A kind of ERW X65 hot-rolled coils and its manufacture method |
| CN105568143A (en) * | 2016-03-15 | 2016-05-11 | 首钢总公司 | Thick pipeline steel hot continuous rolling steel belt easy to coil and excellent in low-temperature performance and manufacturing method thereof |
| CN105568143B (en) * | 2016-03-15 | 2017-11-17 | 首钢总公司 | It is a kind of easily to batch and the think gauge pipe line steel hot continuous rolling steel band and its manufacture method of low temperature performance excellent |
| WO2021017521A1 (en) * | 2019-08-01 | 2021-02-04 | 江阴兴澄特种钢铁有限公司 | Low yield-to-tensile ratio thin specification pipeline steel manufacturing method |
| CN115125432A (en) * | 2022-06-13 | 2022-09-30 | 本钢板材股份有限公司 | Manufacturing method of 650 MPa-grade high-strength and light-weight steel for automobile spoke |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2962472C (en) | High-toughness hot-rolled high-strength steel with yield strength of grade 800 mpa and preparation method thereof | |
| CN101649420B (en) | Ultra-strength, high toughness and low yield ratio steel and steel plate and manufacturing method thereof | |
| CN103014554B (en) | Low-yield-ratio high-tenacity steel plate and manufacture method thereof | |
| CN103320717B (en) | Ultra high-strength high titanium steel plate with yield strength of 960 MPa and preparing method of same | |
| CN102758133B (en) | 1000MPa-level automobile steel with high product of strength and elongation and manufacturing method thereof | |
| CN104805374B (en) | A kind of thickness Q460E steel plate more than 120mm and manufacture method thereof | |
| WO2018076965A1 (en) | Cold-rolled high-strength steel having tensile strength of not less than 1500 mpa and excellent formability, and manufacturing method therefor | |
| CN103215516A (en) | 700MPa high strength hot rolling Q&P steel and manufacturing method thereof | |
| CN103233183A (en) | Ultrahigh-strength steel plate steel plate with yield strength of 960MPa-level, and manufacturing method thereof | |
| CN103710622A (en) | 690MPa-yield-strength low-yield-tensile-ratio antiseismic steel and manufacturing method thereof | |
| CN106868281A (en) | A kind of ultra-fine grained ferrite/low temperature bainite dual-phase steel and preparation method thereof | |
| CN109280857B (en) | 1200 MPa-grade ultrafast cold-rolled dual-phase steel plate and preparation method thereof | |
| CN109957712A (en) | A kind of soft X70M line steel hot rolling coiled sheet and its manufacturing method | |
| CN109082590A (en) | A kind of high-strength plasticity hot rolling medium managese steel plate and its critical zone roll preparation method | |
| CN103882330A (en) | Non-quenched and tempered steel plate with low yield ratio and super high strength and producing method thereof | |
| CN103469065A (en) | 340MPa-grade HSLA vehicle structural steel and production method thereof | |
| CN105925905B (en) | 780MPa grades of hot-rolled dual-phase steels of Nb-Ti systems and its production method | |
| CN103667912B (en) | The heat treating method of a kind of Low Alloy Steel Plate and steel plate | |
| CN102965568A (en) | Phase-change toughened low-alloy steel plate and preparation method thereof | |
| CN109182669B (en) | High-hardness high-toughness easy-welding pre-hardened plastic die steel and preparation method thereof | |
| CN102363868A (en) | Pipeline steel and production method thereof | |
| CN105695869A (en) | Hot rolled sheet steel with 450MPa grade yield strength for bridges and manufacturing method thereof | |
| CN113862446B (en) | Production method of X70 pipeline steel with high heating temperature | |
| CN103147004A (en) | Hot-rolled low-alloy high-strength steel plate and preparation method for same | |
| CN103147002A (en) | Low-alloy high-strength steel plate and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20120229 |