CN107287515A - Low-temperature impact-resistant height extension Q345E hot-strips and production method - Google Patents

Low-temperature impact-resistant height extension Q345E hot-strips and production method Download PDF

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Publication number
CN107287515A
CN107287515A CN201710432550.4A CN201710432550A CN107287515A CN 107287515 A CN107287515 A CN 107287515A CN 201710432550 A CN201710432550 A CN 201710432550A CN 107287515 A CN107287515 A CN 107287515A
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low
hot
rolling
temperature
temperature impact
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Inventor
张玉文
贾丽慧
李建设
刘爱平
任振远
吕苗苗
方锡婕
陈秋良
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TANGSHAN STAINLESS STEEL CO Ltd
Tangshan Iron and Steel Group Co Ltd
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TANGSHAN STAINLESS STEEL CO Ltd
Tangshan Iron and Steel Group Co Ltd
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Publication of CN107287515A publication Critical patent/CN107287515A/en
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    • 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
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing 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
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • 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
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

The invention discloses a kind of low-temperature impact-resistant height extension Q345E hot-strips and production method, the hot-strip chemical composition composition and weight/mass percentage composition are：C：0.15~0.18%, Mn：0.4~0.7%, S≤0.015%, P≤0.025%, Si≤0.03%, Als >=0.015%, N≤0.0060%, remaining is iron and inevitable impurity；Production method includes steel-making, heating, rolling and refrigerating work procedure.The principle of present invention application controlled rolling and controlled cooling bainitic transformation reinforcing, reduction cost of alloy improves intensity and improves low-temperature impact toughness, low-silicon and low-phosphorous composition hot dip galvanized coating surface quality and adhesive force are strong, corrosion resistance is strong, meet the demand of cold district photovoltaic bracket, electric power tower, electric power tower, engineering construction scaffold and other galvanizing structural steels, be conducive to improving occupation rate of market, great economic benefit can be produced.

Description

Low-temperature impact-resistant height extension Q345E hot-strips and production method
Technical field
The invention belongs to metallurgical technology field, and in particular to a kind of low-temperature impact-resistant height extension Q345E hot-strips and life Production method.
Background technology
With continuing to develop for China's economic construction, the application of low-alloy high-tensile structural steel is more and more extensive.Q345E is low Alloy high strength steel is largely exported, and it has the good characteristic such as high intensity, high tenacity, shock resistance, corrosion-resistant, as engineering structure One of preferred material is designed, is widely used in photovoltaic bracket, electric power tower, engineering construction scaffold and other galvanizing structures Part, wide market.
Competitive pressure is also increasing in the continuous expansion of China Steel industry production capacity, industry, how to improve quality, reduction Production cost, generate profit maximization turn into major steel mill's urgent problem.Controlled rolling and controlled cooling is studied and application turns into development Trend.
Application for a patent for invention number 201310231768.5 discloses a kind of flexible manufacturing method of hot rolled steel plate, and it is adopted With two-stage control rolling and the quick cooling technique of leading portion, using leading portion cooling technique, cooling velocity is in 30~50 DEG C/s, still General hot rolling layer cold line will ensure that the strip of different size has 30~50 DEG C/s cooldown rate control difficulty larger.
The content of the invention
The technical problem to be solved in the present invention is to provide a kind of low-temperature impact-resistant height extension Q345E hot-strips；The present invention Additionally provide a kind of production method of low-temperature impact-resistant height extension Q345E hot-strips.
In order to solve the above technical problems, the present invention is adopted the technical scheme that：A kind of low-temperature impact-resistant height extension Q345E heat Strip is rolled, the hot-strip chemical composition composition and weight/mass percentage composition are：C：0.15~0.18%, Mn：0.4~0.7%, S ≤ 0.015%, P≤0.025%, Si≤0.03%, Als >=0.015%, N≤0.0060%, remaining is iron and inevitable impurity.
Hot-strip mechanical property of the present invention（Laterally）For：475~550MPa of tensile strength, yield strength 380~ 475MPa, elongation after fracture A ＞ 30%；- 40 DEG C of Charpy v-notch ballistic work >=100J/cm2。
Hot-strip thickness specification of the present invention is 1.5~6.0mm.
Present invention also offers a kind of production method of low-temperature impact-resistant height extension Q345E hot-strips, the producer Method includes steel-making, heating, rolling and refrigerating work procedure.
Refrigerating work procedure of the present invention, using three-stage cooling technique, after belt steel rolling, carry out first it is strong for the first time cold, it is cold Speed >=30 DEG C/s, is cooled to 670~710 DEG C, then in 1.5~3s of the temperature range air cooling.
Refrigerating work procedure of the present invention, the strip progress after strong cold, air cooling is strong second cold for the first time, cooling rate >=30 DEG C/ S, is cooled to 400~500 DEG C of coiling temperature.
Steel making working procedure of the present invention, it is blast-melted through top and bottom combined blown converter, LF refining using the smelting process of clean steel Processing, tapping ladle chemistry composition and weight/mass percentage composition are：C：0.15~0.18%, Mn：0.4~0.7%, S≤ 0.015%, P≤0.025%, Si≤0.03%, Als >=0.015%, N≤0.0060%, remaining is iron and inevitable impurity.
Heating process of the present invention, slab heating temperature is 1180~1230 DEG C.
Rolling process of the present invention, 1080~1130 DEG C of roughing start rolling temperature.
Rolling process of the present invention, 1000~1080 DEG C of finish rolling start rolling temperature, 810~850 DEG C of finishing temperature.
The mentality of designing of the present invention：
The present invention is added without microalloy element and designed using low manganese, low silicon content, is carried using the reinforcing of ferrite-bainite multiphase High intensity and processability, in identical Q345 intensity ranks elongation percentage ＞ 30%, average specific routine Q345 is high by 10%.With good Low temperature impact properties, -40 DEG C of Charpy v-notch ballistic works have reached 100J/cm2More than, while more conventional Q345 composition designs （Mn contents 1.0%~1.35%）Mn contents about 0.4% or so are reduced, alloy dosage and rolling load has been saved, has reduced and be produced into This.
The low-silicon and low-phosphorous composition design of the inventive method, Zinc attachability is strong, corrosion-resistant, the middle relatively low manganese content of carbon without Nb, V, The addition of the microalloy elements such as Ti has stronger cost advantage, and Slow cooling work is used near Ac1 critical-temperatures by regulating and controlling Skill, by controlling ferritic phase to change ratio and crystallite dimension, takes to form bayesian to regulate and control warm rolling in the distribution of C in steel, control Body phase control with changed scale and bayesian shape；Intensity and processability are improved by the reinforcing of ferrite-bainite multiphase and low temperature resistant Impact property.
The inventive method carries out controlled rolling and controlled cooling, uniform ferritic structure, the analysis for controlling pearlite using the low silicon design of low manganese Go out ratio, produce 1.5~6.0mm of thickness specification product.
The detection method of low-temperature impact-resistant height extension Q345E hot-strips of the present invention refers to GB/T912-2008 carbon knots Structure steel and low-alloy high-tensile structural steel SPHC and steel band（Thickness is less than 3mm）With GB-T 3274-2007 carbon structures Steel and low-alloy structural steel hot rolling steel plate and steel band（Thickness >=3mm）.Note：Thickness is less than 3mm without impact test.
It is using the beneficial effect produced by above-mentioned technical proposal：1st, the inventive method application controlled rolling and controlled cooling bayesian body phase Become the principle of reinforcing, reduce cost of alloy, improve intensity and improve low-temperature impact toughness, low-silicon and low-phosphorous composition is hot-dip galvanized Layer surface quality and adhesive force are strong, and corrosion resistance is strong, meets cold district photovoltaic bracket, electric power tower, electric power tower, engineering and builds The demand of scaffold and other galvanizing structural steels is built, great economic benefit can be produced.2nd, the inventive method product is met The use demand of user, mechanical property（Laterally）：Tensile strength is controlled in 475~550MPa（Standard requirement >=470MPa）, bend Strength control is taken in 380~475MPa（Standard requirement >=340MPa）, elongation after fracture A controls ＞ 30%（GB/T1591 standards will Ask >=21%）, steel belt molding is functional, and subzero 40 DEG C of low temperature Charpy v-notch ballistic work has reached 100~115J/cm2, symbol Close the subzero 40 DEG C of Charpy v-notch ballistic work difference >=34J/cm of Q345E2Standard requirement.
3rd, the inventive method Q345E uses three-stage cooling technique, and intensity is improved using the reinforcing of ferrite-bainite multiphase And processability, under conditions of proof strength and low-temperature impact toughness, the addition of alloy especially manganese, and nothing can be reduced The addition of the microalloy elements such as Nb, V, Ti, has saved alloy dosage and rolling load, saves cost, is conducive to raising market to account for There is rate, considerable economic benefit can be produced.
Brief description of the drawings
Fig. 1 is the metallographic structure figure of the hot-strip of embodiment 1（200X, longitudinal direction）.
Embodiment
With reference to specific embodiment, the present invention is further detailed explanation.
The production method of this low-temperature impact-resistant height extension Q345E hot-strips includes steel-making, heating, rolling and bosher Sequence, concrete technology step is as described below：
（1）Steel making working procedure：It is blast-melted through top and bottom combined blown converter, LF refining furnace processing, tapping using the smelting process of clean steel Ladle chemistry is constituted and weight/mass percentage composition is：C：0.15~0.18%, Mn：0.4~0.7%, S≤0.015%, P≤ 0.025%, Si≤0.03%, Als >=0.015%, N≤0.0060%, remaining is iron and inevitable impurity.
（2）Heating process：Molten steel is casting continuously to form slab, and slab heating temperature is 1180~1230 DEG C.
（3）Rolling process：1080~1130 DEG C of roughing start rolling temperature, batches into Coil Box after five passage roughing, removes Through seven frame hot continuous rollings after squama, and use lubrication and rolling, 1000~1080 DEG C of finish rolling start rolling temperature, finishing temperature 810~850 ℃；Rear steel plate thickness is rolled for 1.5~6.0mm.
（4）Refrigerating work procedure：Carried out first using three-stage cooling technique, after belt steel rolling it is strong for the first time cold, cooling rate >=30 DEG C/ S, is cooled to 670~710 DEG C, then in 1.5~3s of the temperature range air cooling；The strip after strong cold, air cooling carries out for the first time Secondary strong cold, cooling rate >=30 DEG C/s, are cooled to 400~500 DEG C of coiling temperature, and low-temperature impact-resistant height extension Q345E is produced after batching Hot-strip.
Embodiment 1
The present embodiment low-temperature impact-resistant height extension Q345E hot-strips thickness is 3.0mm, its chemical composition composition and quality percentage Content is：C：0.18%, Mn：0.50%, S：0.002%, P：0.010%, Si：0.02%, Als：0.038%, N：0.0020%, remaining For iron and inevitable impurity.
Production method includes steel-making, heating, rolling and refrigerating work procedure, and concrete technology step is as described below：
（1）Steel making working procedure：It is blast-melted through top and bottom combined blown converter, LF refining furnace processing, tapping using the smelting process of clean steel Ladle chemistry is constituted and weight/mass percentage composition is：C：0.18%, Mn：0.50%, S：0.002%, P：0.010%, Si：0.02%, Als：0.038%, N：0.0020%, remaining is iron and inevitable impurity.
（2）Heating process：Molten steel is casting continuously to form slab, and slab heating temperature is 1200 DEG C.
（3）Rolling process：1100 DEG C of roughing start rolling temperature, batches into Coil Box after five passage roughing, is passed through after de-scaling Seven frame hot continuous rollings, and use lubrication and rolling, 1030 DEG C of finish rolling start rolling temperature, 840 DEG C of finishing temperature；Rolling rear steel plate thickness is 3.0mm。
（4）Refrigerating work procedure：Carry out strong cold, 80 DEG C/s of cooling rate for the first time first using three-stage cooling technique, after belt steel rolling, 700 DEG C are cooled to, then in temperature range air cooling 2.0s；Strip progress for the first time after strong cold, air cooling is strong second cold, cold 100 DEG C/s of speed, is cooled to 450 DEG C of coiling temperature, and this low-temperature impact-resistant height extension Q345E hot-strips are produced after batching.
After tested, actual performance is Q345E mechanical property obtained by the present embodiment（Laterally）：Tensile strength 530MPa, bend Take intensity 453MPa, elongation 34%；The subzero 40 DEG C of low temperature Charpy v-notch ballistic works of 2.5*10*55mm have reached 26.5J, change 2.5*10*55mm standard samples ballistic work is counted as 106/cm2。
The metallographic structure figure of Q345E hot-strips obtained by the present embodiment（200X, longitudinal direction）See Fig. 1, it is seen that metallographic structure compared with Uniformly, ferrite and bainite duplex structure are organized as, remaining embodiment accompanying drawing is similar, slightly.
Embodiment 2
The present embodiment low-temperature impact-resistant height extension Q345E hot-strips thickness is 5.5mm, its chemical composition composition and quality percentage Content is：C：0.18%, Mn：0.49%, S：0.006%, P：0.020%, Si：0.02%, Als：0.041%, N：0.0046%, remaining For iron and inevitable impurity.
Production method includes steel-making, heating, rolling and refrigerating work procedure, and concrete technology step is as described below：
（1）Steel making working procedure：It is blast-melted through top and bottom combined blown converter, LF refining furnace processing, tapping using the smelting process of clean steel Ladle chemistry is constituted and weight/mass percentage composition is：C：0.18%, Mn：0.49%, S：0.006%, P：0.020%, Si：0.02%, Als：0.041%, N：0.0046%, remaining is iron and inevitable impurity.
（2）Heating process：Molten steel is casting continuously to form slab, and slab heating temperature is 1190 DEG C.
（3）Rolling process：1090 DEG C of roughing start rolling temperature, batches into Coil Box after five passage roughing, is passed through after de-scaling Seven frame hot continuous rollings, and use lubrication and rolling, 1000 DEG C of finish rolling start rolling temperature, 835 DEG C of finishing temperature；Rolling rear steel plate thickness is 5.5mm。
（4）Refrigerating work procedure：Carried out first using three-stage cooling technique, after belt steel rolling it is strong for the first time cold, 100 DEG C of cooling rate/ S, is cooled to 690 DEG C, then in temperature range air cooling 2.5s；Strip progress for the first time after strong cold, air cooling is strong second cold, 130 DEG C/s of cooling rate, is cooled to 450 DEG C of coiling temperature, and this low-temperature impact-resistant height extension Q345E hot-strips are produced after batching.
After tested, actual performance is Q345E mechanical property obtained by the present embodiment（Laterally）：Tensile strength 491MPa, bend Take intensity 414MPa, elongation 39.5%；The subzero 40 DEG C of low temperature Charpy v-notch ballistic works of 5*10*55mm have reached 57.5J, change 10*10*55mm standard samples ballistic work is counted as 115J/cm2。
Embodiment 3
The present embodiment low-temperature impact-resistant height extension Q345E hot-strips thickness is 2.0mm, its chemical composition composition and quality percentage Content is：C：0.17%, Mn：0.45%, S：0.012%, P：0.020%, Si：0.025%, Als：0.035%, N：0.0035%, remaining For iron and inevitable impurity.
Production method includes steel-making, heating, rolling and refrigerating work procedure, and concrete technology step is as described below：
（1）Steel making working procedure：It is blast-melted through top and bottom combined blown converter, LF refining furnace processing, tapping using the smelting process of clean steel Ladle chemistry is constituted and weight/mass percentage composition is：C：0.17%, Mn：0.45%, S：0.012%, P：0.020%, Si： 0.025%, Als：0.035%, N：0.0035%, remaining is iron and inevitable impurity.
（2）Heating process：Molten steel is casting continuously to form slab, and slab heating temperature is 1200 DEG C.
（3）Rolling process：1100 DEG C of roughing start rolling temperature, batches into Coil Box after five passage roughing, is passed through after de-scaling Seven frame hot continuous rollings, and use lubrication and rolling, 1050 DEG C of finish rolling start rolling temperature, 840 DEG C of finishing temperature；Rolling rear steel plate thickness is 2.0mm。
（4）Refrigerating work procedure：Carry out strong cold, 90 DEG C/s of cooling rate for the first time first using three-stage cooling technique, after belt steel rolling, 710 DEG C are cooled to, then in temperature range air cooling 1.8s；Strip progress for the first time after strong cold, air cooling is strong second cold, cold 100 DEG C/s of speed, is cooled to 450 DEG C of coiling temperature, and this low-temperature impact-resistant height extension Q345E hot-strips are produced after batching.
After tested, actual performance is Q345E mechanical property obtained by the present embodiment（Laterally）：Tensile strength 538MPa, bend Take intensity 446MPa, elongation 32%.
Embodiment 4
The present embodiment low-temperature impact-resistant height extension Q345E hot-strips thickness is 3.5mm, its chemical composition composition and quality percentage Content is：C：0.17%, Mn：0.40%, S：0.002%, P：0.025%, Si：0.012%, Als：0.035%, N：0.0045%, remaining For iron and inevitable impurity.
Production method includes steel-making, heating, rolling and refrigerating work procedure, and concrete technology step is as described below：
（1）Steel making working procedure：It is blast-melted through top and bottom combined blown converter, LF refining furnace processing, tapping using the smelting process of clean steel Ladle chemistry is constituted and weight/mass percentage composition is：C：0.17%, Mn：0.40%, S：0.002%, P：0.025%, Si： 0.012%, Als：0.035%, N：0.0045%, remaining is iron and inevitable impurity.
（2）Heating process：Molten steel is casting continuously to form slab, and slab heating temperature is 1200 DEG C.
（3）Rolling process：1100 DEG C of roughing start rolling temperature, batches into Coil Box after five passage roughing, is passed through after de-scaling Seven frame hot continuous rollings, and use lubrication and rolling, 1035 DEG C of finish rolling start rolling temperature, 835 DEG C of finishing temperature；Rolling rear steel plate thickness is 3.5mm。
（4）Refrigerating work procedure：Carried out first using three-stage cooling technique, after belt steel rolling it is strong for the first time cold, 110 DEG C of cooling rate/ S, is cooled to 670 DEG C, then in temperature range air cooling 1.5s；Strip progress for the first time after strong cold, air cooling is strong second cold, 140 DEG C/s of cooling rate, is cooled to 410 DEG C of coiling temperature, and this low-temperature impact-resistant height extension Q345E hot-strips are produced after batching.
After tested, actual performance is Q345E mechanical property obtained by the present embodiment（Laterally）：Tensile strength 542MPa, bend Take intensity 483MPa, elongation 33%；The subzero 40 DEG C of low temperature Charpy v-notch ballistic works of 2.5*10*55mm have reached 27J, conversion It is 108J/cm into 10*10*55mm standard samples ballistic work2。
Embodiment 5
The present embodiment low-temperature impact-resistant height extension Q345E hot-strips thickness is 1.5mm, its chemical composition composition and quality percentage Content is：C：0.15%, Mn：0.45%, S：0.008%, P：0.012%, Si：0.03%, Als：0.015%, N：0.0035%, remaining For iron and inevitable impurity.
Production method includes steel-making, heating, rolling and refrigerating work procedure, and concrete technology step is as described below：
（1）Steel making working procedure：It is blast-melted through top and bottom combined blown converter, LF refining furnace processing, tapping using the smelting process of clean steel Ladle chemistry is constituted and weight/mass percentage composition is：C：0.15%, Mn：0.45%, S：0.008%, P：0.012%, Si：0.03%, Als：0.015%, N：0.0035%, remaining is iron and inevitable impurity.
（2）Heating process：Molten steel is casting continuously to form slab, and slab heating temperature is 1220 DEG C.
（3）Rolling process：1120 DEG C of roughing start rolling temperature, batches into Coil Box after five passage roughing, is passed through after de-scaling Seven frame hot continuous rollings, and use lubrication and rolling, 1070 DEG C of finish rolling start rolling temperature, 850 DEG C of finishing temperature；Rolling rear steel plate thickness is 1.5mm。
（4）Refrigerating work procedure：Carry out strong cold, 30 DEG C/s of cooling rate for the first time first using three-stage cooling technique, after belt steel rolling, 710 DEG C are cooled to, then in temperature range air cooling 3s；The strip after strong cold, air cooling carries out strong second cold, cooling rate for the first time 70 DEG C/s, it is cooled to 500 DEG C of coiling temperature, this low-temperature impact-resistant height extension Q345E hot-strips is produced after batching.
After tested, actual performance is Q345E mechanical property obtained by the present embodiment（Laterally）：Tensile strength 520MPa, bend Take intensity 430MPa, elongation 38%.
Embodiment 6
The present embodiment low-temperature impact-resistant height extension Q345E hot-strips thickness is 6.0mm, its chemical composition composition and quality percentage Content is：C：0.16%, Mn：0.63%, S：0.010%, P：0.020%, Si：0.01%, Als：0.036%, N：0.0060%, remaining For iron and inevitable impurity.
Production method includes steel-making, heating, rolling and refrigerating work procedure, and concrete technology step is as described below：
（1）Steel making working procedure：It is blast-melted through top and bottom combined blown converter, LF refining furnace processing, tapping using the smelting process of clean steel Ladle chemistry is constituted and weight/mass percentage composition is：C：0.16%, Mn：0.63%, S：0.010%, P：0.020%, Si：0.01%, Als：0.036%, N：0.0060%, remaining is iron and inevitable impurity.
（2）Heating process：Molten steel is casting continuously to form slab, and slab heating temperature is 1230 DEG C.
（3）Rolling process：1080 DEG C of roughing start rolling temperature, batches into Coil Box after five passage roughing, is passed through after de-scaling Seven frame hot continuous rollings, and use lubrication and rolling, 1010 DEG C of finish rolling start rolling temperature, 810 DEG C of finishing temperature；Rolling rear steel plate thickness is 6.0mm。
（4）Refrigerating work procedure：Carried out first using three-stage cooling technique, after belt steel rolling it is strong for the first time cold, 100 DEG C of cooling rate/ S, is cooled to 705 DEG C, then in temperature range air cooling 1.5s；Strip progress for the first time after strong cold, air cooling is strong second cold, 30 DEG C/s of cooling rate, is cooled to 430 DEG C of coiling temperature, and this low-temperature impact-resistant height extension Q345E hot-strips are produced after batching.
After tested, actual performance is Q345E mechanical property obtained by the present embodiment（Laterally）：Tensile strength 475MPa, bend Take intensity 380MPa, elongation 31%；The subzero 40 DEG C of low temperature Charpy v-notch ballistic works of 5*10*55mm have reached 51.5J, conversion It is 103J/cm into 10*10*55mm standard samples ballistic work2。
Embodiment 7
The present embodiment low-temperature impact-resistant height extension Q345E hot-strips thickness is 5.5mm, its chemical composition composition and quality percentage Content is：C：0.16%, Mn：0.70%, S：0.015%, P：0.018%, Si：0.025%, Als：0.025%, N：0.0035%, remaining For iron and inevitable impurity.
Production method includes steel-making, heating, rolling and refrigerating work procedure, and concrete technology step is as described below：
（1）Steel making working procedure：It is blast-melted through top and bottom combined blown converter, LF refining furnace processing, tapping using the smelting process of clean steel Ladle chemistry is constituted and weight/mass percentage composition is：C：0.16%, Mn：0.70%, S：0.015%, P：0.018%, Si： 0.025%, Als：0.025%, N：0.0035%, remaining is iron and inevitable impurity.
（2）Heating process：Molten steel is casting continuously to form slab, and slab heating temperature is 1180 DEG C.
（3）Rolling process：1130 DEG C of roughing start rolling temperature, batches into Coil Box after five passage roughing, is passed through after de-scaling Seven frame hot continuous rollings, and use lubrication and rolling, 1080 DEG C of finish rolling start rolling temperature, 820 DEG C of finishing temperature；Rolling rear steel plate thickness is 5.5mm。
（4）Refrigerating work procedure：Carry out strong cold, 50 DEG C/s of cooling rate for the first time first using three-stage cooling technique, after belt steel rolling, 680 DEG C are cooled to, then in temperature range air cooling 2.5s；Strip progress for the first time after strong cold, air cooling is strong second cold, cold 50 DEG C/s of speed, is cooled to 400 DEG C of coiling temperature, and this low-temperature impact-resistant height extension Q345E hot-strips are produced after batching.
After tested, actual performance is Q345E mechanical property obtained by the present embodiment（Laterally）：Tensile strength 520MPa, bend Take intensity 430MPa, elongation 36.5%；The subzero 40 DEG C of low temperature Charpy v-notch ballistic works of 5*10*55mm have reached 55J, conversion It is 110J/cm into 10*10*55mm standard samples ballistic work2。
Above example is only used to illustrative and not limiting technical scheme, although with reference to above-described embodiment to this hair It is bright to be described in detail, it will be understood by those within the art that：Still the present invention can be modified or be waited With replacement, any modification or partial replacement without departing from the spirit and scope of the present invention, it all should cover the power in the present invention Among sharp claimed range.

Claims (10)

1. a kind of low-temperature impact-resistant height extension Q345E hot-strips, it is characterised in that the hot-strip chemical composition composition and Weight/mass percentage composition is：C：0.15~0.18%, Mn：0.4~0.7%, S≤0.015%, P≤0.025%, Si≤0.03%, Als >= 0.015%, N≤0.0060%, remaining is iron and inevitable impurity.
2. a kind of low-temperature impact-resistant height extension Q345E hot-strips according to claim 1, it is characterised in that the heat Rolling band steel mechanical property is：475~550MPa of tensile strength, 380~475MPa of yield strength, elongation after fracture A ＞ 30%；-40 DEG C Charpy v-notch ballistic work >=100J/cm2。
3. a kind of low-temperature impact-resistant height extension Q345E hot-strips according to claim 1, it is characterised in that the heat Belt steel thickness specification is rolled for 1.5~6.0mm.
4. the producer based on a kind of low-temperature impact-resistant height extension Q345E hot-strips described in claim 1-3 any one Method, it is characterised in that the production method includes steel-making, heating, rolling and refrigerating work procedure.
5. a kind of production method of low-temperature impact-resistant height extension Q345E hot-strips according to claim 4, its feature exists In, the refrigerating work procedure, using three-stage cooling technique, after belt steel rolling, strong cold, cooling rate >=30 DEG C/s for the first time are carried out first, 670~710 DEG C are cooled to, then in 1.5~3s of the temperature range air cooling.
6. a kind of production method of low-temperature impact-resistant height extension Q345E hot-strips according to claim 4, its feature exists In, the refrigerating work procedure, strong second cold, cooling rate >=30 DEG C/s of the strip progress after strong cold, air cooling, are cooled to and batch temperature for the first time 400~500 DEG C of degree.
7. a kind of producer of low-temperature impact-resistant height extension Q345E hot-strips according to claim 4-6 any one Method, it is characterised in that the steel making working procedure, tapping ladle chemistry composition and weight/mass percentage composition are：C：0.15~ 0.18%, Mn：0.4~0.7%, S≤0.015%, P≤0.025%, Si≤0.03%, Als >=0.015%, N≤0.0060%, remaining For iron and inevitable impurity.
8. a kind of producer of low-temperature impact-resistant height extension Q345E hot-strips according to claim 4-6 any one Method, it is characterised in that the heating process, slab heating temperature is 1180~1230 DEG C.
9. a kind of producer of low-temperature impact-resistant height extension Q345E hot-strips according to claim 4-6 any one Method, it is characterised in that the rolling process, 1080~1130 DEG C of roughing start rolling temperature.
10. a kind of producer of low-temperature impact-resistant height extension Q345E hot-strips according to claim 4-6 any one Method, it is characterised in that the rolling process, 1000~1080 DEG C of finish rolling start rolling temperature, 810~850 DEG C of finishing temperature.
CN201710432550.4A 2017-06-09 2017-06-09 Low-temperature impact-resistant height extension Q345E hot-strips and production method Withdrawn CN107287515A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109778076A (en) * 2019-02-12 2019-05-21 唐山不锈钢有限责任公司 The production method of low-crackle sensitive S550MC Hot Rolling Automobile structural steel band
CN112322990A (en) * 2020-11-23 2021-02-05 浙江宝武钢铁有限公司 Limit-resistant low-temperature hot-rolled angle steel and preparation method thereof

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006063367A (en) * 2004-08-25 2006-03-09 Sumitomo Metal Ind Ltd Method for producing hot rolled steel sheet
CN102747277A (en) * 2012-06-07 2012-10-24 河北钢铁股份有限公司 Method for producing Q345 heat rolling plate rolls with excellent performance by low silicon low manganese
CN105132797A (en) * 2015-09-25 2015-12-09 唐山不锈钢有限责任公司 Low-cost Grade50 hot-rolled strip steel and production method thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006063367A (en) * 2004-08-25 2006-03-09 Sumitomo Metal Ind Ltd Method for producing hot rolled steel sheet
CN102747277A (en) * 2012-06-07 2012-10-24 河北钢铁股份有限公司 Method for producing Q345 heat rolling plate rolls with excellent performance by low silicon low manganese
CN105132797A (en) * 2015-09-25 2015-12-09 唐山不锈钢有限责任公司 Low-cost Grade50 hot-rolled strip steel and production method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109778076A (en) * 2019-02-12 2019-05-21 唐山不锈钢有限责任公司 The production method of low-crackle sensitive S550MC Hot Rolling Automobile structural steel band
CN112322990A (en) * 2020-11-23 2021-02-05 浙江宝武钢铁有限公司 Limit-resistant low-temperature hot-rolled angle steel and preparation method thereof

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Application publication date: 20171024