CN104928592B - High-strength low-temperature-resistant steel and heat processing technology thereof - Google Patents
High-strength low-temperature-resistant steel and heat processing technology thereof Download PDFInfo
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Abstract
The invention provides high-strength low-temperature-resistant steel. The steel is composed of, by mass, 2.0-7.05% of nickel, 0.02-0.1% of carbon, 0.02-0.1% of silicon, 0.60-8.00% of manganese, 0.3-0.5% of chrome, 0.05-0.6% of molybdenum, 0.02-0.3% of copper, 0.03-2.0% of aluminum, smaller than or equal to 0.010% of phosphorus, smaller than or equal to 0.002% of sulfur, 0.004-0.010% of nitrogen, 0.0005-0.002% of oxygen, 0.0005-0.005% of calcium, and the balance iron. The invention further provides the heat processing technology and application of the high-strength low-temperature-resistant steel. By the adoption of the high-strength low-temperature-resistant steel and the heat processing technology thereof, low-temperature toughness is high, structural steel used in a low-temperature environment can be manufactured, application cost is reduced, and economical applicability is high.
Description
Technical field
The invention belongs to the technical field of cryogenic steel, is related to a kind of high-strength low temperature resistant steel and its Technology for Heating Processing, specifically
It is related to a kind of low temperature resistant steel of the low Ni systems ferrite type of high intensity and its Technology for Heating Processing.
Background technology
In the case where energy day is becoming tight, the production and trade of Global LNG (LNG) are enlivened increasingly.Liquefaction day
So gas (liquefied natural gas, referred to as LNG) is that natural gas is compressed, it is warm to be cooled to (- 161.5 DEG C) of its boiling point
Become liquid after degree, usual LNG storage is in -161.5 DEG C, the low-temperature storage tank of 0.1MPa or so.It is natural with gaseous state
Gas is compared, and the natural gas after liquefaction only has the 1/625 of original volume, is highly convenient for storing and is transported, and the liquefaction of Unit Weight
Natural gas ground transportation costs are only the 1/6～1/7 of pipeline transportation expense.
At present, LNG ship is internationally recognized high-tech, highly difficult, high added value " three high " product, and LNG ship is zero
The specialized ships of transport liquefied gases under lower 162 DEG C of low temperature, because LNG Storage, Transport temperature is below -162 DEG C, this is required
Material for accumulating liquefied natural gas has good impact flexibility, enough anti-brittle cracking and crack arrest energy under ultralow temperature
Power.Meanwhile, Hyundai iron company has started to set about the exploitation of low-temperature flexibility cut deal and H profile steel, current main research
Direction is the resistance to extremely low temperature H profile steel of high intensity, i.e., yield strength is in more than 460MPa, it is ensured that the steel of -20 DEG C of impact flexibility, mainly
For the hurricane deck of container ship, be conducive to the exploitation in arctic navigation channel.
Rich Ni ferrite types low-temperature steel alloying level is relatively low, and cheap, cryogenic property is good, is developing progressively as most
Low temperature structure material with practicality, is widely used in manufacturing the tun of storage and transport cryogenic liquid.Wherein, 9Ni
The cryogenic property of steel is more excellent, is the rich Ni ferrites shaped steel for uniquely using under deep cooling, and decapacitation is in -162 DEG C of level storing liquids
Change outside natural gas, can be also used for storing liquid oxygen (- 183 DEG C), the structural material of liquid nitrogen (- 196 DEG C) can also apply to H
In the exploitation of shaped steel and cut deal.It is well known that, good low temperature notched toughness is also that the most important technology of low-temperature steel will
Ask, and Ni elements affect very big to the low-temperature flexibility of low-temperature steel, content is higher to affect bigger.Therefore, it is necessary to high-strength resistance to low
The further research and discussion of warm steel.
The content of the invention
The shortcoming of prior art in view of the above, it is an object of the invention to provide a kind of high-strength low temperature resistant steel and its heat
Handling process, for solving prior art in lack with good low temperature obdurability combination and can be used in being made under low temperature environment
The problem of structural steel and preparation method thereof.
For achieving the above object and other related purposes, first aspect present invention provides a kind of high-strength low temperature resistant steel, by with
The element composition of lower mass percent：
Ni (nickel)：2.0-7.05%；C (carbon)：0.02-0.1%；Si (silicon)：0.02-0.1%；Mn (manganese)：0.60-
8.00%；Cr (chromium)：0.3-0.5%；Mo (molybdenum)：0.05-0.6%；Cu (copper)：0.02-0.3%；Al (aluminium)：0.03-
2.0%；P (phosphorus)：≤ 0.010%；S (sulphur)：≤ 0.002%；N (nitrogen)：0.004-0.010%；O (oxygen)：0.0005-
0.002%；Ca (calcium)：0.0005-0.005%；Balance of Fe (iron).
Preferably, the high-strength low temperature resistant steel of described one kind, element composition optionally following one：
1) a kind of high-strength low temperature resistant steel A, is made up of the element of following mass percent：
Ni：6.85-7.05%；C：0.045-0.060%；Si：0.05-0.08%；Mn：0.69-5.00%；Cr：0.3-
0.4%；Mo：0.05-0.4%；Cu：0.02-0.3%；Al：0.036-0.040%；P：≤ 0.009%；S：≤ 0.002%；N：
0.004-0.005%；O：0.0005-0.002%；Ca：0.0005-0.005%；Balance of Fe；
2) a kind of high-strength low temperature resistant steel B, is made up of the element of following mass percent：
Ni：2.0-5.75%；C：0.02-0.1%；Si：0.02%-0.1%；Mn：4.75-8.00%；Cr：0.3-
0.4%；Mo：0.15-0.60%；Cu：0.02-0.3%；Al：0.044-0.048%；P：≤ 0.009%；S：≤ 0.002%；
N：0.004-0.005%；O：0.0005-0.002%；Ca：0.0005-0.005%；Balance of Fe；
3) a kind of high-strength low temperature resistant steel C, is made up of the element of following mass percent：
Ni：5.75-6.85%；C：0.02-0.1%；Si：0.02-0.1%；Mn：0.60-1.00%；Cr：0.3-
0.4%；Mo：0.05-0.60%；Cu：0.02-0.3%；Al：0.036-0.048%；P：≤ 0.009%；S：≤ 0.002%；
N：0.004-0.005%；O：0.0005-0.002%；Ca：0.0005-0.005%；Balance of Fe.
It is highly preferred that the high-strength low temperature resistant steel of described one kind, is made up of the element of following mass percent：
Ni：2.0-5.75%；C：0.03-0.08%；Si：0.04%-0.08%；Mn：4.75-7.00%；Cr：0.3-
0.4%；Mo：0.2-0.40%；Cu：0.02-0.1%；Al：0.044-0.048%；P：≤ 0.009%；S：≤ 0.002%；N：
0.004-0.005%；O：0.0005-0.002%；Ca：0.0005-0.001%；Balance of Fe.
The element composition of high-strength low temperature resistant steel in the present invention, wherein, nickel is the most basic most important alloying element of low-temperature steel.
Nickel is non-carbide former, and it does not form carbide with carbon effect.With the raising of nickel content, As points are reduced during cooling,
The stability increase of austenite, when nickel content is sufficiently high, or even does not also change under -196 DEG C of liquid nitrogen temperature, so as to
Single phase austenite tissue is obtained, therefore nickel is to form the element with stable austenite, adds the nickel in steel to form solid solution with matrix
Body, can significantly improve ferritic toughness, so as to improve the low-temperature flexibility of low-temperature steel.With the increase of nickel content in steel, low temperature
Toughness is improved, and toughness-brittlenss transformation temperature is reduced, therefore nickel is again to improve the low-temperature flexibility of steel, reduce ductile brittle transition
The maximally effective element of temperature.In low-temperature steel add nickel amount number will according to using temperature and to low-temperature flexibility requirement determine,
Nickel content is too high, not only uneconomical, and can damage the processing performances such as welding, while can also reduce the yield strength of material.
Carbon can significantly improve the intensity of low-temperature steel, but low-temperature steel is all generally mild steel, on the premise of proof strength, should
The carbon content in steel is reduced as far as possible, to improve the low-temperature flexibility of steel, transition temperature is reduced, and improves weldability.Manganese is in low-temperature steel
Effect and nickel class seemingly, it is also effective to reducing Ductile-brittle transition temperature, by improving low-temperature steel in Mn/C ratios,
Be remarkably improved the toughness of steel, in addition, replace part of nickel with appropriate manganese, can also reduces cost, improve economy.Additionally,
The elements such as appropriate aluminium are added in low-temperature steel, the crystal grain of steel can be refined, particularly using controlled rolling and control cooling
Under the conditions of, can significantly improve the low-temperature flexibility of low-temperature steel.
Simultaneously for nickel system low-temperature steel, containing for the impurity elements such as S, P, N and O is above all controlled in smelting process
Amount, this is the important means for improving low-temperature steel low-temperature flexibility.And adding appropriate Cu elements to improve strength and ductility product, Cu is enriched in
More austenites are caused to remain in austenite, and the invigoration effect of the precipitate due to Cu, intensity is improved and do not dropped again
Low toughness.
Second aspect present invention provides a kind of high-strength low temperature resistant Heat-Treatment of Steel technique, comprises the following steps：
1) by each element component in Steel material by smelting after proportioning mixing, then sheet billet continuous casting is into ingot casting；
It is described to smelt for conventional smelting iron and steel technology.
Preferably, the slab continuous casting technology is：After using 180t molten iron preprocessing station desulfurization, using the de- P of converter process
After technology blowing is skimmed, in LF refined-smelting ladle furnace deep desulfurizations, while adjusting alloying component；Si-Ca lines are squeezed into after molten steel, in RH
After stove vacuum circulation degassing, after carrying out slab continuous casting, reconditioning after slow cooling.
2) by step 1) in obtain ingot casting carry out air cooling after multistep hot rolling；
Preferably, the multistep hot rolling is comprised the following steps：
The first step：Hot-rolled temperature：1045-1055 DEG C, temperature retention time：165-175 minutes；
Second step：Hot-rolled temperature：975-985 DEG C, temperature retention time：115-125 minutes；
3rd step：Hot-rolled temperature：845-855 DEG C, temperature retention time：85-95 minutes；
4th step：Hot-rolled temperature：825-835 DEG C, temperature retention time：65-75 minutes；
5th step：Hot-rolled temperature：805-815 DEG C, temperature retention time：45-55 minutes；
6th step：Hot-rolled temperature：775-785 DEG C, temperature retention time：35-45 minutes；
7th step：Hot-rolled temperature：765-775 DEG C, temperature retention time：27-37 minutes；
8th step：Finishing temperature：745-755 DEG C, temperature retention time：20-30 minutes.
It is highly preferred that the multistep hot rolling is comprised the following steps：
The first step：Hot-rolled temperature：1050 DEG C, temperature retention time：170 minutes；
Second step：Hot-rolled temperature：980 DEG C, temperature retention time：120 minutes；
3rd step：Hot-rolled temperature：850 DEG C, temperature retention time：90 minutes；
4th step：Hot-rolled temperature：830 DEG C, temperature retention time：70 minutes；
5th step：Hot-rolled temperature：810 DEG C, temperature retention time：50 minutes；
6th step：Hot-rolled temperature：780 DEG C, temperature retention time：40 minutes；
7th step：Hot-rolled temperature：770 DEG C, temperature retention time：32 minutes；
8th step：Finishing temperature：750 DEG C, temperature retention time：25 minutes.
Preferably, every time reduction ratio of the multistep hot rolling is maintained at 20-30%.
The reduction ratio is commonly used when referring to rolling and forging and stamping and represents that the reduction ratio of relative deformation represents deformation extent, works as multistep
Rolling reduction ratio is maintained in a stability range as far as possible when, effect of rolling is preferable.
3) by step 2) ingot casting after hollow cold carries out QLT heat treatments, obtains final product high-strength low temperature resistant Steel material.
Preferably, the QLT heat treatments are comprised the following steps：
A) ingot casting after air cooling is carried out more than A3 temperature high temperature quenching；
It is highly preferred that the A3 temperature is 720-770 DEG C.Most preferably, the A3 temperature is 740 DEG C.
It is highly preferred that the condition of high temperature quenching is：Temperature：850±1℃；Time：60 ± 1 minutes.
B) and then, by Jing step a) high temperature quenching after ingot casting two-phase section insulation after quench；
It is highly preferred that the temperature of the two-phase section is 550-750 DEG C.Most preferably, the temperature of the two-phase section is 580-
720℃。
It is highly preferred that the two-phase section is higher than A1 temperature 15-25 DEG C than the temperature being incubated.Most preferably, the two-phase section
Temperature than being incubated is higher than A1 temperature 15 DEG C.
C) it is last, by Jing step b) two-phase sections than insulation after the ingot casting that quenches be tempered isothermal holding simultaneously water below A1 temperature
It is cold.
It is highly preferred that the A1 temperature is 550-630 DEG C.Most preferably, the A1 temperature is 580 DEG C.
It is highly preferred that the temperature is lower than A1 temperature 60-80 DEG C.Most preferably, the temperature is than A1 temperature
It is low 75 DEG C.
The QLT heat treatments are high temperature quenching+two-phase section quenching+tempering technique, include multi-step process.Wherein, first
The tissue that step high temperature quenching is obtained is substantially lath martensite；And in second step two-phase section quenching process, partial martensite meeting
Reverse is changed into austenite, and separates out on martensite lath and original austenite crystal prevention, respectively laminar and irregular block group
Knit；The 3rd step subsequently tempering and it is water cooled process to room temperature, the austenite that this part reverted austenite comes can it is most of again
It is transformed into martensite, this partial martensite is referred to as new martensite, the martensite without transformation becomes tempered martensite, then remains
A part of austenite and tiny acicular ferrite.So, high-strength low temperature resistant Steel material by QLT process after, its microscopic structure
For tiny acicular ferrite+tempered martensite+a small amount of retained austenite tissue.It can be seen that, compared with normative heat treatment (QT), QT
In the austenite of only bulk form exist, and the tissue that QLT process is formed is more tiny, austenite have with lamellar form and
Bulk is present, and QLT becomes apparent from for the effect of stabilization of austenite.
Preferably, the ingot casting carried out after QLT heat treatments is also performed to be water-cooled to room temperature water-cooled process.
Third aspect present invention provides the purposes on the structural steel that a kind of high-strength low temperature resistant steel is used at low ambient temperatures.
Preferably, the structural steel for using at low ambient temperatures is cut deal, H profile steel, LNG and LPG cargo ships, storage
Deposit tank material.
As described above, a kind of high-strength low temperature resistant steel and its Technology for Heating Processing of the present invention, mainly for the manufacture of low temperature environment
The lower structural steel for using, including cut deal, H profile steel, LNG and LPG cargo ships, storage tank material.This kind of steel use 5.5Ni
Steel material realizes the replacement to 9Ni steel under ultralow temperature, under the environment that can be used at -196 DEG C of ultralow temperature due to 9Ni steel, for example -
The LNG ship of transport liquefied gases under 163 DEG C of low temperature；And in the market 5.5Ni steel be produce, process, store and transport ethene (with
Based on liquefied ethylene LEG) needed for critical material, using temperature be -120 DEG C；It can be seen that the cost and its condition of work of 5.5Ni steel
9Ni steel is less than, therefore with more preferable application prospect.
This kind of steel in the present invention not only have the yield strength higher than richness Ni materials, but also with excellent low temperature resistant
Performance.Especially this kind steel have tiny acicular ferrite+tempered martensite+a small amount of retained austenite tissue, yield strength
More than 500MPa, elongation percentage is more than 15%, and it has the combination of low temperature obdurability, with excellent low-temperature flexibility, its -196 DEG C
Lower ballistic work is more than 120J.Meanwhile, the present invention is used in QLT techniques on the high-strength low temperature resistant steel of hot rolling, makes the dislocation in tissue
Reduce, crystal grain is also refined, and due to the effect of alloying element partition, remain a part of austenite, the impurity unit of matrix
Element also absorbed, the toughness under low temperature is greatly improved so that using territory greatly promote, and can substantially reduce should
Cost, there is very big economic serviceability.
Description of the drawings
Fig. 1 is shown as the QLT of the high-strength low temperature resistant steel of the present invention and processes schematic diagram.
Fig. 2 is shown as light microscope micro-organization chart 2a, 2b of the high-strength low temperature resistant steel of embodiment 2 in the present invention, its
In, 2a is the light microscope micro-organization chart of rolled；2b is the light microscope micro-organization chart after QLT process.
Fig. 3 is shown as light microscope micro-organization chart 3a, 3b of the high-strength low temperature resistant steel of embodiment 3 in the present invention, its
In, 3a is the light microscope micro-organization chart of rolled；3b is the light microscope micro-organization chart after QLT process.
Fig. 4 is shown as the stress strain curve ratio in the present invention after the process of the rolled of the high-strength low temperature resistant steel of embodiment 2 and QLT
Compared with schematic diagram.
Fig. 5 is shown as the stress strain curve ratio in the present invention after the process of the rolled of the high-strength low temperature resistant steel of embodiment 3 and QLT
Compared with schematic diagram.
Fig. 6 is shown as liquid nitrogen temperature ballistic work after rolled and the QLT of the high-strength low temperature resistant steel of the present invention are processed and compares to show
It is intended to.
Specific embodiment
The present invention is expanded on further with reference to specific embodiment, it should be appreciated that these embodiments are merely to illustrate the present invention
Rather than limit the scope of the invention.
Embodiments of the present invention are illustrated below by way of specific instantiation, those skilled in the art can be by this specification
Disclosed content understands easily other advantages and effect of the present invention.The present invention can also pass through concrete realities different in addition
The mode of applying is carried out or applies, the every details in this specification can also based on different viewpoints with application, without departing from
Various modifications and changes are carried out under the spirit of the present invention.
The reagent that following examples the are used such as element such as nickel, carbon, silicon, manganese, chromium, molybdenum, copper, aluminium, phosphorus, sulphur, nitrogen, oxygen, calcium, iron
It is commercially available, device such as RH refining furnaces, come the light microscope also commercially available acquisition of card DM2700 types.
Embodiment 1
The formula of high-strength low temperature resistant Steel material is as follows：Ni：6.85-7.05%；C：0.045-0.060%；Si：0.05-
0.08%；Mn：0.69-5.00%；Cr：0.3-0.4%；Mo：0.05-0.4%；Cu：0.02-0.3%；Al：0.036-
0.040%；P：≤ 0.009%；S：≤ 0.002%；N：0.004-0.005%；O：0.0005-0.002%；Ca：0.0005-
0.005%；Balance of Fe.
By each element component in above-mentioned formula by smelting after proportioning mixing, then sheet billet continuous casting is into ingot casting, carries out multistep heat
Rear air cooling is rolled, The ingot casting thickness is 240mm.Wherein, multistep hot-rolled condition is：Respectively continuously 1050,980,850,830,810,
780th, at a temperature of 770,750 DEG C, reduction ratio is respectively 29.17%, 29.41%, 25%, 22.22%, 21.43%, 20%,
20%th, 21.88%, temperature retention time is respectively 170,120,90,70,50,40,32,25 minutes.The concrete data of multistep hot rolling are shown in
Table 1, concrete steps are shown in Fig. 1.Hot rolled rear ingot casting is detected into that under an optical microscope Fig. 2 a see in concrete micro-organization chart.
Then, the ingot casting after will be cold carries out QLT heat treatments, i.e., high temperature quenching is carried out more than A3 temperature, and A3 temperature is
720-770 DEG C, high temperature quenching condition be：Temperature：849-851℃；Time：59-61 minutes.Quench after two-phase section is than insulation
Fire, the temperature of two-phase section is 550-750 DEG C, and two-phase section is higher than A1 temperature 15-25 DEG C than the temperature being incubated.In A1 temperature with next time
Water-cooled process after fire, A1 temperature is 550-630 DEG C, and temperature is lower than A1 temperature 60-80 DEG C, obtains final product high-strength low temperature resistant Steel material
Sample 1#.And the ingot casting Jing after QLT process is detected into that under an optical microscope Fig. 2 b see in concrete micro-organization chart.
Embodiment 2
The formula of high-strength low temperature resistant Steel material is as follows：Ni：2.0-5.75%；C：0.02-0.1%；Si：0.02%-
0.1%；Mn：4.75-8.00%；Cr：0.3-0.4%；Mo：0.15-0.60%；Cu：0.02-0.3%；Al：0.044-
0.048%；P：≤ 0.009%；S：≤ 0.002%；N：0.004-0.005%；O：0.0005-0.002%；Ca：0.0005-
0.005%；Balance of Fe.
By each element component in above-mentioned formula by smelting after proportioning mixing, then sheet billet continuous casting is into ingot casting, carries out multistep heat
Rear air cooling is rolled, The ingot casting thickness is 240mm.Wherein, multistep hot-rolled condition is：Respectively continuously 1050,980,850,830,810,
780th, at a temperature of 770,750 DEG C, reduction ratio is respectively 29.17%, 29.41%, 25%, 22.22%, 21.43%, 20%,
20%th, 21.88%, temperature retention time is respectively 170,120,90,70,50,40,32,25 minutes.The concrete data of multistep hot rolling are shown in
Table 1, concrete steps are shown in Fig. 1.Hot rolled rear ingot casting is detected into that under an optical microscope Fig. 3 a see in concrete micro-organization chart.
Then, the ingot casting after will be cold carries out QLT heat treatments, i.e., high temperature quenching is carried out more than A3 temperature, and A3 temperature is
720-770 DEG C, high temperature quenching condition be：Temperature：849-851℃；Time：59-61 minutes.Quench after two-phase section is than insulation
Fire, the temperature of two-phase section is 550-750 DEG C, and two-phase section is higher than A1 temperature 15-25 DEG C than the temperature being incubated.In A1 temperature with next time
Water-cooled process after fire, A1 temperature is 550-630 DEG C, and temperature is lower than A1 temperature 60-80 DEG C, obtains final product high-strength low temperature resistant Steel material
Sample 2#.And the ingot casting Jing after QLT process is detected into that under an optical microscope Fig. 3 b see in concrete micro-organization chart.
The multistep isothermal hot rolling tables of data of the high-strength low temperature resistant steel of table 1
| Passage | Temperature retention time (minute) | Reduction ratio (%) | Temperature (DEG C) |
| 1 | 170 | 29.17% | 1050 |
| 2 | 120 | 29.41% | 980 |
| 3 | 90 | 25.00% | 850 |
| 4 | 70 | 22.22% | 830 |
| 5 | 50 | 21.43% | 810 |
| 6 | 40 | 20.00% | 780 |
| 7 | 32 | 20.00% | 770 |
| 8 | 25 | 21.88% | 750 |
Embodiment 3
High-strength low temperature resistant Steel material sample 1-2# in embodiment 1-2 is respectively adopted into light microscope carries out tissue and residual
Remaining austenite observation, concrete outcome is shown in Fig. 2 a, 2b, 3a, 3b.
More unordered through the sample tissue of rolled from Fig. 2 a, 2b, 3a, 3b, deformation is very serious, there is a lot
Dislocation and defect, this tissue its toughness will certainly be very poor, but after QLT process, tissue is tempered martensite+pin
Columnar ferrite+a small amount of austenite, the metaplasia that hot rolling is caused all is heat-treated elimination, and tissue is also refined.
Meanwhile, using the residual austenite content of Magnetic Measurement, concrete data are shown in Table 2.As shown in Table 2, at QLT is warm
The austenite content of the steel after reason has significantly increase, so as to improve the low-temperature flexibility of material.This has benefited from QLT process
During intercritical hardening, the alloying element (C, Mn, Ni) in martensite is assembled in austenite, austenite is improve in a large number steady
It is qualitative, and in final step drawing process, alloying element further can spread in austenite, tempered martensite matrix is miscellaneous
Matter content is reduced, and cryogenic property is lifted.The austenite remained in matrix can improve the toughness of nickel system low-temperature steel, in alloying element
With can consider to obtain as far as possible many austenites in the design of Technology for Heating Processing, form multiphase structure, austenite can be passivated
Crack tip so that Crack Extension is obstructed.
The residual austenite content table of the Magnetic Measurement of table 2
| Project | Processing stage | Austenite content (%) |
| Sample 1# | QLT process | 2.4209 |
| Sample 2# | QLT process | 3.2737 |
| Sample 1# | Rolled | 0.8454 |
| Sample 2# | Rolled | 0.8166 |
Embodiment 4
High-strength low temperature resistant Steel material sample 1-2# in embodiment 1-2 is carried out into respectively normal temperature stretching experiment, concrete outcome
See Fig. 4,5.From Fig. 4,5, the probe intensity that direct hot rolling is obtained is higher, but elongation percentage is too low, through QLT process after intensity
Decline, but yield strength is still greater than 500MPa, but elongation percentage is substantially double, and more than 15%, this has benefited from heat treatment
During to processing hardening elimination, the purification of structure refinement and matrix.
Embodiment 5
High-strength low temperature resistant Steel material sample 1-2# in embodiment 1-2 is carried out into respectively rushing at -196 DEG C of liquid nitrogen temperature
Experiment is hit, concrete outcome is shown in Fig. 6.It will be appreciated from fig. 6 that high-strength low temperature resistant Steel material sample 1-2# is after QLT heat treatments, liquid nitrogen temperature
Impact toughness value under degree is all greatly improved, and its ballistic work is all higher than 120J, the ballistic work of sample 1# is promoted to from 22J
The ballistic work of 142J, sample 2# is promoted to 156J from 31J, considerably beyond in ASTM standard for the ballistic work of 9Ni steel
Standard 34J, it is possible using providing in lower temperature for 5.5Ni, so as to reduce the purpose of Ni contents.
Embodiment 6
The formula of high-strength low temperature resistant Steel material is as follows：Ni：5.75-6.85%；C：0.02-0.1%；Si：0.02-0.1%；
Mn：0.60-1.00%；Cr：0.3-0.4%；Mo：0.05-0.60%；Cu：0.02-0.3%；Al：0.036-0.048%；P：
≤ 0.009%；S：≤ 0.002%；N：0.004-0.005%；O：0.0005-0.002%；Ca：0.0005-0.005%；Surplus
For Fe.
By each element component in above-mentioned formula by smelting after proportioning mixing, then sheet billet continuous casting is into ingot casting, carries out multistep heat
Rear air cooling is rolled, The ingot casting thickness is 240mm.Wherein, multistep hot-rolled condition is：Respectively continuously 1045,975,845,825,805,
775th, at a temperature of 765,745 DEG C, every time reduction ratio is maintained between 20-30%, temperature retention time is respectively 175,125,95,
75th, 55,45,37,30 minutes.
Then, the ingot casting after will be cold carries out QLT heat treatments, i.e., high temperature quenching is carried out more than A3 temperature, and A3 temperature is
720-770 DEG C, high temperature quenching condition be：Temperature：850℃；Time：60 minutes.Quench after two-phase section is than insulation, two-phase section
Temperature be 580-720 DEG C, two-phase section than be incubated temperature it is higher than A1 temperature 15-25 DEG C.Water-cooled after being tempered below A1 temperature
Process, A1 temperature is 550-630 DEG C, and temperature is lower than A1 temperature 60-80 DEG C, obtains final product high-strength low temperature resistant Steel material sample 3#.
The impact toughness value that the high-strength low temperature resistant Steel material sample 3# of gained contains under more austenite, liquid nitrogen temperature has and significantly carries
Height, with good low temperature obdurability, and with excellent yield strength.
Embodiment 7
The formula of high-strength low temperature resistant Steel material is as follows：Ni：2.0-5.75%；C：0.03-0.08%；Si：0.04%-
0.08%；Mn：4.75-7.00%；Cr：0.3-0.4%；Mo：0.2-0.40%；Cu：0.02-0.1%；Al：0.044-
0.048%；P：≤ 0.009%；S：≤ 0.002%；N：0.004-0.005%；O：0.0005-0.002%；Ca：0.0005-
0.001%；Balance of Fe.
By each element component in above-mentioned formula by smelting after proportioning mixing, then sheet billet continuous casting is into ingot casting, carries out multistep heat
Rear air cooling is rolled, The ingot casting thickness is 240mm.Wherein, multistep hot-rolled condition is：Respectively continuously 1055,985,855,835,815,
785th, at a temperature of 775,755 DEG C, every time reduction ratio is maintained between 20-30%, temperature retention time is respectively 165,115,85,
65th, 45,35,27,20 minutes.
Then, the ingot casting after will be cold carries out QLT heat treatments, i.e., high temperature quenching is carried out more than A3 temperature, and A3 temperature is 740
DEG C, the condition of high temperature quenching is：Temperature：850℃；Time：60 minutes.Quench after two-phase section is than insulation, the temperature of two-phase section
For 595 DEG C, two-phase section is higher than A1 temperature 15 DEG C than the temperature being incubated.Water-cooled process after being tempered below the A1 temperature, A1 temperature is
580 DEG C, temperature is lower than A1 temperature 75 DEG C, obtains final product high-strength low temperature resistant Steel material sample 4#.The high-strength low temperature resistant Steel material of gained
The impact toughness value that sample 4# contains under more austenite, liquid nitrogen temperature is greatly improved, tough with good low temperature
Property, and with excellent yield strength.
So, the present invention effectively overcomes various shortcoming of the prior art and has high industrial utilization.
The principle and its effect of above-described embodiment only illustrative present invention, it is of the invention not for limiting.It is any ripe
Know the personage of this technology all can carry out modifications and changes under the spirit and the scope without prejudice to the present invention to above-described embodiment.Cause
This, such as those of ordinary skill in the art is complete with institute under technological thought without departing from disclosed spirit
Into all equivalent modifications or change, should by the present invention claim be covered.
Claims (8)
1. a kind of high-strength low temperature resistant steel, it is characterised in that be made up of the element of following mass percent：
Ni：2.0-5.75%；C：0.02-0.1%；Si：0.02%-0.1%；Mn：4.75-8.00%；Cr：0.3-0.4%；
Mo：0.15-0.60%；Cu：0.02-0.3%；Al：0.044-0.048%；P：≤ 0.009%；S：≤ 0.002%；N：
0.004-0.005%；O：0.0005-0.002%；Ca：0.0005-0.005%；Balance of Fe.
2. a kind of high-strength low temperature resistant Heat-Treatment of Steel technique according to claim 1, it is characterised in that including following step
Suddenly：
1) by each element component in Steel material by smelting after proportioning mixing, then sheet billet continuous casting is into ingot casting；
2) by step 1) in obtain ingot casting carry out air cooling after multistep hot rolling；
3) by step 2) ingot casting after hollow cold carries out QLT heat treatments, obtains final product high-strength low temperature resistant Steel material；
Step 2) in, the multistep hot rolling is comprised the following steps：
The first step：Hot-rolled temperature：1045-1055 DEG C, temperature retention time：165-175 minutes；
Second step：Hot-rolled temperature：975-985 DEG C, temperature retention time：115-125 minutes；
3rd step：Hot-rolled temperature：845-855 DEG C, temperature retention time：85-95 minutes；
4th step：Hot-rolled temperature：825-835 DEG C, temperature retention time：65-75 minutes；
5th step：Hot-rolled temperature：805-815 DEG C, temperature retention time：45-55 minutes；
6th step：Hot-rolled temperature：775-785 DEG C, temperature retention time：35-45 minutes；
7th step：Hot-rolled temperature：765-775 DEG C, temperature retention time：27-37 minutes；
8th step：Finishing temperature：745-755 DEG C, temperature retention time：20-30 minutes.
3. high-strength low temperature resistant Heat-Treatment of Steel technique according to claim 2, it is characterised in that step 3) in, the QLT
Heat treatment is comprised the following steps：
A) ingot casting after air cooling is carried out more than A3 temperature high temperature quenching；
B) and then, by Jing step a) high temperature quenching after ingot casting two-phase section insulation after quench；
C) it is last, the ingot casting quenched Jing after the insulation of step b) two-phase sections is tempered into isothermal holding and water-cooled below A1 temperature.
4. high-strength low temperature resistant Heat-Treatment of Steel technique according to claim 3, it is characterised in that in step a), the A3
Temperature is 720-770 DEG C；High temperature quenching condition be：Temperature：849-851 DEG C, the time：59-61 minutes.
5. high-strength low temperature resistant Heat-Treatment of Steel technique according to claim 3, it is characterised in that in step b), described two
The temperature of phase region is 550-750 DEG C；The temperature of the two-phase section insulation is higher than A1 temperature 15-25 DEG C.
6. high-strength low temperature resistant Heat-Treatment of Steel technique according to claim 3, it is characterised in that in step c), the A1
Temperature is 550-630 DEG C；The temperature is lower than A1 temperature 60-80 DEG C.
7. the purposes on structural steel that high-strength low temperature resistant steel according to claim 1 is used at low ambient temperatures.
8. purposes according to claim 7, it is characterised in that the structural steel for using at low ambient temperatures is middle thickness
Plate, H profile steel, LNG and LPG cargo ships, storage tank material.
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| CN106191391A (en) * | 2016-08-31 | 2016-12-07 | 抚州申铃汽车配件有限责任公司 | A kind of heat treatment method improving collapsible dist collar obdurability |
| KR102043523B1 (en) | 2017-12-24 | 2019-11-12 | 주식회사 포스코 | Low temperature steel materal having excellent toughness in welded zone and method for manufacturing the same |
| CN108285965B (en) * | 2018-01-15 | 2020-04-10 | 中国科学院理化技术研究所 | Quenching-partitioning-deep cooling-tempering treatment process for steel material |
| CN108467991B (en) * | 2018-03-12 | 2020-09-29 | 上海交通大学 | High-strength and high-toughness high manganese steel for ultralow temperature and heat treatment process thereof |
| WO2020128579A1 (en) * | 2018-12-19 | 2020-06-25 | Arcelormittal | Low-carbon, high-strength 9% nickel steels for cryogenic applications |
| CN109536850B (en) * | 2019-01-10 | 2020-10-02 | 北京科技大学 | High-strength-toughness low-yield-ratio thick steel plate and production process thereof |
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