CN106906420A - A kind of low temperature drop stamping auto parts and components, its drop stamping technique and its manufacture method - Google Patents
A kind of low temperature drop stamping auto parts and components, its drop stamping technique and its manufacture method Download PDFInfo
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- CN106906420A CN106906420A CN201511009922.XA CN201511009922A CN106906420A CN 106906420 A CN106906420 A CN 106906420A CN 201511009922 A CN201511009922 A CN 201511009922A CN 106906420 A CN106906420 A CN 106906420A
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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
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- 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
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
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- 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
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- 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
- C21D8/0236—Cold rolling
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- 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
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
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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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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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
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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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
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
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- 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
- C21D2211/001—Austenite
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- 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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- 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
- C21D2211/008—Martensite
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Abstract
The invention discloses a kind of low temperature drop stamping auto parts and components, its microstructure is martensite+austenite+ferrite, and its chemical element mass percent is：C：0.1%~0.3%, Si：0.1%~2.0%, Mn：3%~7%, Al：0.01%~0.06%, P≤0.02%, S≤0.02%, N≤0.005%, balance of Fe and other inevitable impurity.In addition, the invention also discloses the drop stamping technique of the low temperature drop stamping auto parts and components.In addition the invention also discloses the manufacture method of the low temperature drop stamping auto parts and components, it includes step successively：1) smelt；2) cast；3) hot rolling；4) anneal；5) pickling；6) it is cold rolling；7) the heating and thermal insulation temperature of drop stamping, wherein drop stamping is 700-850 DEG C, and soaking time is 2-10min, to complete complete austenitizing.Low temperature drop stamping auto parts and components of the present invention also have preferable tensile ductility and excellent strong plasticity matching concurrently while with intensity higher.
Description
Technical field
The present invention relates to a kind of metallic element and its manufacture method, more particularly to a kind of auto parts and components and its
Manufacture method.
Background technology
The related industry field of continuous improvement with to(for) vehicle safety and loss of weight energy saving requirement, zero, automobile
The intensity of part is also stepped up therewith.It is that the dual phase steel of 1180MPa is extensive in automobile manufacturing field
Be applied in cold stamping steel.Meanwhile, the martensite steel of 1500MPa is also applied to the shapes such as bumper
On simple part.But, because many automobile reinforcers are complex-shaped, the martensite steel of 1500MPa without
Method realizes cold punching pressing formation, hot press-formed thus to arise at the historic moment.Hot press-formed is to be heated to steel plate
More than 750 DEG C, held for some time is carried out after abundant Ovshinsky, carry out it is hot press-formed, by mould
By steel plate quenching to room temperature, to obtain the full martensitic structure part of 1500MPa and above intensity rank.
Because drop stamping steel shapes at high temperature, the reinforcer complex therefore, it is possible to strike out shape,
And resilience will not be produced, while the dimensional accuracy of reinforcer is high, so as to obtained extensively in automobile manufacturing field
General application.During 2006, about 100,000,000 drop stamping steel parts are in worldwide production, mesh
The preceding whole world is annual about to produce 300,000,000 drop stamping steel parts.
Drop stamping steel (22MnB5 steel) of the prior art is to obtain full martensite group by die quenching
The parts knitted, thus tensile strength can reach 1500MPa and more than.However, such Steel material
Percentage of total elongation is fairly limited, and only 5~6% or so, therefore, being considered as under some working environments can not
For crucial safe parts.For the resistance to fracture of material under the impact absorption energy and shock loading to parts
The consideration of property, automobile manufacturing field wishes that hot forming parts have more preferable tensile ductility.At present, it is main
Impact absorption energy is improved by combining the material of different-thickness/mechanical property on part, for example, spelling
Welding plate (TWB) and thickening plate (VRB) etc..How by Steel material in itself come improve its heat punching
The pressure strong plasticity of steel, so as to lift the tensile ductility of parts on the premise of parts intensity is ensured,
International research is simultaneously few.In addition, the heating-up temperature of drop stamping steel is generally between 930~950 DEG C,
Heating-up temperature is higher, and thermal energy consumption is also big.If drop stamping steel making technical process can be significantly decreased
In heating-up temperature, then be conducive to energy-saving and emission-reduction, and can further reduce the production of drop stamping steel
Manufacturing cost.
Because of this it may be desirable to obtain a kind of auto parts and components material, it has intensity higher and preferably stretching
Ductility.At the same time, enterprise is it is also expected to can be by heating energy consumption before drop stamping steel part drop stamping
Reduce, manufacturing cost is greatly reduced.
The content of the invention
An object of the present invention is to provide a kind of low temperature drop stamping auto parts and components, auto parts and components tool
There is intensity and preferable tensile ductility higher.Meanwhile, the auto parts and components have been also equipped with excellent strong modeling
Property matching, be conducive to improving the impact absorption energy of auto parts and components being made up of the steel.
To achieve these goals, the present invention proposes a kind of low temperature drop stamping auto parts and components, its microcosmic group
Martensite+austenite+ferrite is woven to, the chemical element mass percent of the low temperature drop stamping auto parts and components
For：
C：0.1%~0.3%；
Si：0.1%~2.0%；
Mn：3%~7%；
Al：0.01%~0.06%；
P≤0.02%；
S≤0.02%；
N≤0.005%；
Balance of Fe and other inevitable impurity.
The design principle of each chemical element in low temperature drop stamping auto parts and components of the present invention is：
Carbon：Carbon is typical solution strengthening element in steel, while it can also improve the stability of austenite,
Be conducive to retaining at room temperature the retained austenite of certain volume fraction, so as to produce phase-change induced plastic
(TRIP) effect.For the technical program, when carbon element content is less than 0.1%, the intensity of steel
It is relatively low, and when carbon element content is higher than 0.3%, the performance of steel can then deteriorate, particularly disadvantageous in Steel material
Welding performance.Therefore, the carbon content in low temperature drop stamping auto parts and components of the present invention needs to set
It is set to 0.1%~0.3%.
Silicon：Silicon is the essential elements of deoxidation in steel making.Silicon does not only have certain solution strengthening effect, also with suppression
The effect of Carbide Precipitation processed.Once silicone content is less than 0.1%, it is difficult to sufficient deoxidation effect is obtained in steel
Really.However, the silicone content combination property that can also influence steel too high.In addition appropriate element silicon may also operate as
The effect for preventing cementite from separating out, so as to improve the stability of austenite in cooling procedure.In consideration of it, needing
Silicone content in low temperature drop stamping auto parts and components is controlled to 0.1%~2%, and preferably 0.3%~
1.5%.
Manganese：Manganese drop as effective alloying element, its transition temperature that can reduce the α-γ phases in steel
The temperature of low Ae1 and Ae3.Because the manganese content in auto parts and components of the present invention is 3%~7%,
The increase of manganese content causes that steel of the invention have much lower Ovshinsky compared to existing 22MnB5 steel
Body temperature, the manufacture work of the auto parts and components can be significantly reduced from there through the design of Mn contents
The heating and thermal insulation temperature of the drop stamping in skill, that is to say, that the heating and thermal insulation temperature of drop stamping of the prior art
Degree can be greatly reduced from 930~950 DEG C, and auto parts and components so of the present invention are compared to existing
The manufacturing cost of some 22MnB5 steel will be remarkably decreased.In addition, the design by Mn contents may be used also
To delay recovery and recrystallization and crystal grain to grow up, refinement microstructure, so as to make the crystallite dimension control in steel
System under a threshold value (for example, control crystallite dimension≤3 μm).Being designed by rich Mn can play crystal grain
Refining effect, and improve the stability of austenite in steel.When temperature is reduced to room temperature, phase transformation is produced in steel
Induced plastic effect (TRIP effects), on the one hand improves the strong plasticity of steel grade, on the other hand reduces drop stamping
Heating and thermal insulation temperature.Additionally, manganese also substantially increases the quenching degree of steel so that obtain the critical of martensite
Cooling rate is greatly reduced.Therefore, the manganese content in low temperature drop stamping auto parts and components of the present invention should
It is set to 3%~7%, and preferably 5%~7%.
Aluminium：Aluminium has deoxidation in steelmaking process, and the addition of aluminium is to improve the degree of purity of molten steel.
Additionally, the nitrogen that aluminium can also be fixed in steel, and form stable compound, effective crystal grain thinning with nitrogen.Meanwhile,
Aluminium is added in steel, and there is prevention cementite to separate out, and promote the effect of reverse martensitic transformation in steel.Therefore, need
Aluminium content in auto parts and components of the present invention is limited between 0.01%~0.06% scope.
Further, in low temperature drop stamping auto parts and components of the present invention each chemical element content is expired
Foot：24.2C (%) -2.8Si (%)+Mn (%) -10.1Al (%) >=2, C, Si, Mn in formula
Represent the mass percent of respective element respectively with Al, that is to say, that C, Si, Mn, Al are substituted into formula
Numerical value be numerical value before percentage sign, such as during C content is 0.2% embodiment, the generation of C in the formula
It is exactly 0.2 to enter numerical value..
In the technical program, although the addition of Mn can reduce complete austenitizing temperature, due to this
Also need to add other alloying elements to ensure the mechanical property of steel grade in invention steel, and these elements may
Austenitizing temperature can be improved, therefore, in order to realize the low heating-up temperature technique of low temperature drop stamping, it is necessary to same
When consider the influence of other alloying elements.Inventor has found during long-term research experiment, to steel
Plant austenitizing to influence four elements the most significant is C, Si, Mn and Al, wherein C reduction austenites
The effect for changing temperature is the strongest, although Mn elements can also reduce austenitizing temperature, capability of influence
It is limited；And the addition of Si and Al and the effect of C and Mn are conversely, complete austenitizing will be greatly improved
Temperature, and Al is several times as much as Si to the ability that austenitizing temperature is lifted.Based on this, inventor's root
Above-mentioned formula is devised according to lot of experiments, to realize the purpose of low austenitizing temperature.
Further, the Phase Proportion of the austenite in low temperature drop stamping auto parts and components of the present invention is
5%~30%.
Further, in low temperature drop stamping auto parts and components of the present invention, the austenite includes
Typical austenite, the Phase Proportion (i.e. typical austenite accounts for the ratio of whole microstructures) of typical austenite is
5~20%.
" the typical austenite " referred in this case refers to the Asia that induced plastic can be deformed upon in deformation process
Stable state austenite.By introducing metastable state austenite in martensitic matrix, can be in material deformation process
Significant phase-change induced plastic (TRIP effects) is produced, so as to improve the impact absorption energy of steel grade.At room temperature
The content of austenite is relevant with the control of Mn contents and crystallite dimension, carries high Mn content, reduces crystal grain chi
It is very little, the volume fraction of austenite at room temperature can be improved.Additionally, exist simultaneously in the material certain fraction (>=
1%) during stable state austenite (only deformed upon in deformation process and do not produce phase transformation), due to austenite sheet
Body has excellent deformability, its plasticity that can equally improve steel grade, but it improves the energy of processing hardening
Power is not so good as metastable state austenite.
Further, in low temperature drop stamping auto parts and components of the present invention, ferritic Phase Proportion
It is≤20%.
Because ferrite intensity is larger, therefore excessively a high proportion of ferrite is unfavorable for improving the strength and ductility product of steel grade.
Further, crystallite dimension≤5 μm of low temperature drop stamping auto parts and components of the present invention.
In low temperature drop stamping auto parts and components of the present invention add content be 3%~7% manganese not only
The heating and thermal insulation temperature of drop stamping can be reduced, (the Mn that grows up of recovery and recrystallization and crystal grain can also be delayed
Diffusion velocity is extremely slow in body-centered cubic structure), the microscopic structure in refinement steel, hence in so that institute of the present invention
The crystallite dimension of the auto parts and components stated is controlled in less than 5 μm.
Further, the chemical element in low temperature drop stamping auto parts and components of the present invention also has 0
＜ Nb≤0.5%, 0 ＜ V≤1.0%, 0 ＜ Ti≤0.5% at least one.
Either above-mentioned alloy element Nb, the single addition of V and/or Ti or compound addition can be played
The effect of crystal grain refinement, and improve the stability of austenite in steel, so as to improve the microstructure of steel
And combination property.The species of above-mentioned alloying element can according to actual needs be designed addition.
Based on above-mentioned technical proposal, the major impurity element in auto parts and components of the present invention is phosphorus,
Sulphur and nitrogen, these impurity elements should be controlled more few better, and the auto parts and components for thus being obtained are got over
It is pure.However, according to the actual smelting level of production process, by impurity element control it is lower produced by
Manufacturing cost is also higher.The degree of purity index of comprehensive steel and the control of manufacturing cost, by impurity element P,
S and N are respectively set as：P≤0.02%, S≤0.02%, N≤0.005%.
Further, the tensile strength >=1500MPa of low temperature drop stamping auto parts and components of the present invention,
And elongation >=15%.
One of plasticity index due to evaluation steel includes elongation, and elongation is bigger, the plasticity of steel
Better, the performance that it can undergo permanent deformation before external force destruction is subjected to is better, therefore, it is beneficial to carry
The impact absorption of the auto parts and components that the steel high are made can be with the fracture resistance energy of material under shock loading.
Low temperature drop stamping auto parts and components of the present invention can be using following this steel plates by drop stamping
Technique is obtained：
A kind of steel plate, its chemical element mass percent is：C：0.1%~0.3%, Si：0.1%~2.0%,
Mn：3%~7%, Al：0.01%~0.06%, P≤0.02%, S≤0.02%, N≤0.005% are remaining
Measure is Fe and other inevitable impurity.
In some embodiments, the microstructure of above-mentioned steel plate is martensite.The tensile strength of the steel plate >=
1200MPa。
In other implementation method, the microstructure of above-mentioned steel plate is ferrite+austenite.The steel plate
Tensile strength >=800MPa.
Further, the chemical element of above-mentioned steel plate also has 0 ＜ Nb≤0.5%, 0 ＜ V≤1.0%, 0 ＜
At least one of Ti≤0.5%.
Further, the Si contents in above-mentioned steel plate are 0.3%~1.5%.
Further, the Mn contents in above-mentioned steel plate are 5%~7%.
Further, in above-mentioned steel plate, its chemical element content meets：24.2C (%) -2.8Si (%)
+ Mn (%) -10.1Al (%) >=2, C, Si, Mn and Al in formula represent the matter of respective element respectively
Amount percentage.
In some embodiments, the manufacture method of above-mentioned steel plate can successively include step：
(1) smelt；
(2) cast；
(3) hot rolling；
(4) anneal；
(5) pickling；
(6) it is cold rolling.
Wherein, in the step (3), heating strand to controlled rolling after 1100~1250 DEG C is opened
It is 950~1150 DEG C to roll temperature, and finishing temperature is 750~900 DEG C, and coiling temperature is 500~850 DEG C, so
After be cooled to room temperature.
In the step (4), annealing temperature is 550~850 DEG C, and the time is not less than 1h.
In the step (6), cold rolling reduction ratio >=35%, it is cold rolling after steel plate microstructure be full horse
Family name's body (i.e. all martensitic structures of microstructure).
Using this manufacture method, the steel plate of all martensite of microstructure can be manufactured, the steel plate it is anti-
Tensile strength is of a relatively high, can reach more than 1200MPa.
In other implementation method, the manufacture method of above-mentioned steel plate can also successively include step：
(1) smelt；
(2) cast；
(3) hot rolling；
(4) anneal；
(5) pickling；
(6) it is cold rolling；
(7) anneal.
Wherein, in the step (3), heating strand to controlled rolling after 1100~1250 DEG C is opened
It is 950~1150 DEG C to roll temperature, and finishing temperature is 750~900 DEG C, and coiling temperature is 500~850 DEG C, so
After be cooled to room temperature.
In the step (4), annealing temperature is 550~850 DEG C, and the time is not less than 1h.
In the step (6), cold rolling reduction ratio >=35%.
In the step (7), annealing temperature is 400~750 DEG C, and annealing time is not less than 60s.
Compared to former manufacture method, the manufacture method increased annealing steps again after cold rolling step, cold
Annealing steps after rolling can cause that steel plate is softer relative to martensite steel plate, while its intensity is also reduced
, but this method can reduce the difficulty of processing of subsequent step.Using the micro- of steel plate obtained in the method
Sight is organized as ferrite+austenite, and its tensile strength is relatively low, can reach more than 800MPa.
Another object of the present invention is to provide a kind of low temperature drop stamping auto parts and components of the present invention
Drop stamping technique, wherein, the heating and thermal insulation temperature of drop stamping is 700~850 DEG C, soaking time is 2~
10min, to complete complete austenitizing.
Compared to the drop stamping temperature that existing drop stamping technique, drop stamping technique of the present invention are used
Low, heating and thermal insulation temperature is only 700~850 DEG C.Due to the manganese content in auto parts and components of the present invention
It is designed as 3%~7% so that auto parts and components of the invention are compared to existing product (for example, 22MnB5
Steel parts) there is lower austenitizing temperature, so, just can be with from there through the design of Mn contents
The heating and thermal insulation temperature of drop stamping of the prior art is reduced to 700~850 DEG C, heat from 930~950 DEG C
Heating and thermal insulation temperature in punch steps is once greatly reduced, then the thermal energy consumption needed for the step
Will significantly decrease.Meanwhile, 3%~7% manganese content in auto parts and components of the invention could also function as
To Grain Refinement Effect, the effect of stabilization of austenite in steel is improved.Meanwhile, once temperature is reduced to room temperature,
Phase-change induced plastic effect (TRIP effects) will be produced during deformation in steel, auto parts and components can be both improved
Strong plasticity, can reduce the low-heat punching press heating and thermal insulation temperature in auto parts and components manufacturing process again.
Further, in above-mentioned drop stamping processing step, heated using nitrogen protection in heating furnace
Insulation, it is 700~850 DEG C to control the heating and thermal insulation temperature, and the soaking time is 2~10min, with
Complete complete austenitizing；Then blank is put into hot stamping die carries out hot press-formed, drop stamping guarantor
The pressure time is 3~15 seconds, and stamping press is 300~1000 tons；After the completion of hot press-formed, blank is in Re Chong
Cooled down in compression mould.
A further object of the present invention is to provide a kind of manufacture method of above-mentioned low temperature drop stamping auto parts and components.
The core of the manufacture method is drop stamping step, and the heating and thermal insulation temperature in drop stamping step is ensuring steel
In microstructure whole austenitizings on the premise of greatly reduced, heating and thermal insulation temperature is significantly
Decline, thermal energy consumption reduction reduces the cost input during manufacturing, be conducive to reaching energy-conservation and subtract
The purpose of row.
In order to reach foregoing invention purpose, the invention discloses the manufacture of above-mentioned low temperature drop stamping auto parts and components
Method, it includes step successively：
(1) smelt；
(2) cast；
(3) hot rolling；
(4) anneal；
(5) pickling；
(6) it is cold rolling；
(7) the heating and thermal insulation temperature of drop stamping, wherein drop stamping be 700~850 DEG C, soaking time be 2~
10min, to complete complete austenitizing.
The core of above-mentioned manufacture method is drop stamping step, and drop stamping temperature is low in this step, and heating is protected
Temperature is only 700~850 DEG C.Because the manganese content in auto parts and components of the present invention is designed as
3%~7% so that steel of the invention have more compared to existing steel (for example, 22MnB5 steel)
Low austenitizing temperature, so, just can be by heat of the prior art from there through the design of Mn contents
The heating and thermal insulation temperature of punching press is reduced to 700~850 DEG C, the heating in drop stamping step from 930~950 DEG C
Holding temperature is once greatly reduced, then the thermal energy consumption needed for the step will also be significantly decreased.
Meanwhile, 3%~7% manganese content in auto parts and components of the invention may also operate as Grain Refinement Effect,
Improve the effect of stabilization of austenite in steel.Meanwhile, once temperature is reduced to room temperature, will be produced in steel during deformation
Raw phase-change induced plastic effect (TRIP effects), can both improve the strong plasticity of steel, and steel can be reduced again
Low-heat punching press heating and thermal insulation temperature in material manufacturing process.
Further, in above-mentioned steps (3), by heating strand to controlled rolling after 1100~1250 DEG C,
Start rolling temperature is 950~1150 DEG C, and finishing temperature is 750~900 DEG C, and coiling temperature is 500~850 DEG C,
Room temperature is subsequently cooled to, makes microstructure be full martensitic structure.
Further, in above-mentioned steps (4), annealing temperature is 550~850 DEG C, and the time is not less than
1h, contains the austenite for 20~40% in the microstructure obtained after annealing.
Based on above-mentioned technical proposal, by full martensite microstructure is formd after hot-rolled step in steel.By
It is high in the hardness of the steel with such microstructure and plasticity is poor, it is necessary to be carried out once before cold rolling step
Annealing, to form 20~40% austenite microstructure after annealing, so as to improve the plasticity of steel plate.
In addition, the steel of the austenite with certain volume fraction also allow for it is follow-up cold rolling.In cold-rolled process, greatly
Partial austenitic microstructure will be again transformed into martensite microstructure.
Further, in above-mentioned steps (6), cold rolling reduction ratio >=35%.
Further, in the step (6), it is cold rolling after can also carry out it is cold rolling after annealing steps,
Annealing temperature is 400~750 DEG C, and annealing time is not less than 60s.
Further, in above-mentioned steps (7), heating and thermal insulation is carried out using nitrogen protection in heating furnace,
It is 700~850 DEG C to control heating and thermal insulation temperature, and soaking time is 2~10min, to complete complete austenite
Change；Then blank is put into hot stamping die carry out it is hot press-formed, the drop stamping dwell time be 3~15
Second, stamping press be 300~1000 tons, it is hot press-formed after the completion of, blank is cooled down in hot stamping die.
When blank is cooled to room temperature in hot stamping die, martensitic traoformation is completed in steel, while retaining one
Determine the austenite of volume fraction.At the same time, phase-change induced plastic effect (TRIP effects) is produced in steel,
Martensitic Transformation causes the plasticity of steel to raise, and not only increases the strong plasticity of auto parts and components, also drops
Thermal energy consumption in low auto parts and components manufacturing process.
Technical scheme by the reasonable control to alloying component, especially for C and Mn elements
The precise control of content, in the case where environment temperature is reduced to room temperature so that TRIP effects are produced in steel
Should, thus improve the intensity and plasticity of auto parts and components.
In addition, the addition quantity of the alloy species of technical scheme is few, Nb, V and/or Ti are
It is preferred that the alloying element for adding, on the premise of the microstructure and mechanical property for ensuring auto parts and components, enters
Optimize to one step the addition of alloying element so that technical scheme more economical rationality.
Low temperature drop stamping auto parts and components of the present invention possess intensity higher, and its tensile strength >=
1500MPa.While the intensity rank is ensured, low temperature drop stamping auto parts and components of the present invention are also
Have good tensile ductility concurrently, its elongation >=15%.
Additionally, low temperature drop stamping auto parts and components of the present invention possess excellent strong plasticity matching, favorably
And can be impacted in the impact absorption for improving the auto parts and components being made up of auto parts and components of the present invention and carried
The fracture resistance energy of material under lotus.
It is obtained in that intensity is high by the manufacture method of low temperature drop stamping auto parts and components of the present invention, moulds
Property is good, and tensile ductility is good and steel of strong plasticity good match.
In addition, the thermal energy consumption of the drop stamping technique of low temperature drop stamping auto parts and components of the present invention is saved,
Cost input economy.
Brief description of the drawings
Fig. 1 is the micro-organization chart of the low temperature drop stamping auto parts and components in embodiment of the present invention 4-2.
Specific embodiment
Below in conjunction with brief description of the drawings and specific embodiment to low temperature drop stamping automobile zero of the present invention
Part and its manufacture method and drop stamping technique make further explanation, but the explanation and explanation are simultaneously
Improper restriction is not constituted to technical scheme.
Embodiment 1-6 and comparative example 1-2
Auto parts and components in above-described embodiment and comparative example are obtained using following step：
(1) smelt：Using converter smelting, control the mass percent of each chemical element as shown in table 1；
(2) cast：Continuous casting obtains strand；
(3) hot rolling：By heating strand to controlled rolling after 1100~1250 DEG C, start rolling temperature is 950~
1150 DEG C, finishing temperature is 750~900 DEG C, and hot rolling plate thickness is not more than 20mm, coiling temperature is 500~
850 DEG C, room temperature is subsequently cooled to, makes microstructure be full martensitic structure；
(4) anneal：Using cover annealing, annealing temperature is 550~850 DEG C, and the time is not less than 1h,
Contain the austenite that volume fraction is 20~40% in the microstructure obtained after annealing；
(5) pickling：Iron scale of the pickling to be produced in removing course of hot rolling and process of bell type annealing；
(6) it is cold rolling：Control cold rolling reduction ratio >=35%；
(7) blanking：Shape according to drop stamping part carries out mould blanking, it would however also be possible to employ laser blanking；
(8) drop stamping：Using nitrogen to protect in heating furnace carries out heating and thermal insulation to improve component surface matter
Amount, it is 700~850 DEG C to control heating and thermal insulation temperature, and soaking time is 2~10min, to complete complete Austria
Family name's body；Then blank is put into hot stamping die carry out it is hot press-formed, the drop stamping dwell time be 3~
15 seconds, stamping press was 300~1000 tons；After the completion of hot press-formed, blank is cooled down in hot stamping die.
In addition, in step (1), can also be smelted using electric furnace or induction furnace.
Additionally, in step (8), it is also possible to carry out heating guarantor using inert gas shielding in heating furnace
Temperature.When the face shaping of auto parts and components is relatively simple, it would however also be possible to employ partial saturation technique.
It should be noted that martensitic traoformation is likely to occur in blank in the cooling procedure of mould, also may be used
Can occur during blank is cooled to room temperature from after mould taking-up, this depends on blank heat in a mold
The punching press dwell time.Upon cooling to room temperature, the austenite that certain volume fraction can be also retained in parts is micro-
See tissue.
In addition, it is necessary to explanation, in embodiment 1-6, what is obtained after step (6) is full geneva
Body steel.In other embodiments, in order to reduce the difficulty of subsequent processing operations, it is also possible in step (6)
It is cold rolling after increase once cold rolling after annealing, annealing temperature be 400~750 DEG C, annealing time is not less than
60s, so that steel plate becomes relatively softer.
Comparative example 2 is 22MnB5 steel auto parts and components of the prior art.
The quality percentage that table 1 lists each chemical element in the auto parts and components of embodiment and comparative example is matched somebody with somebody
Than.
Table 1. (wt%, balance of Fe and the other impurities element in addition to impurity element S, P and N)
Table 2 lists the specific process parameter of the manufacture method of the auto parts and components of embodiment and comparative example.
Table 2
It should be noted that embodiment 4-1 to embodiment 4-4 illustrates them employing shown in table 1
The percent mass proportioning of the chemical element of embodiment 4.Similarly, comparative example 2-1 and comparative example 2-2 are used
The chemical element component of comparative example 2 in table 1.
Auto parts and components sampling to above-described embodiment and comparative example, carries out every Mechanics Performance Testing, will try
The related mechanical property that test is obtained is listed in Table 3 below.
Table 3 lists the mechanical property parameters of embodiment and comparative example.
Table 3
From table 3 it can be seen that the yield strength of each embodiment of this case equal ＞ 690MPa, the equal ＞ of tensile strength
1500MPa, elongation >=15%, illustrates that these auto parts and components possess intensity and good drawing higher
Stretch malleability.
Understood with reference to the content of table 1 and table 3, because the carbon content of comparative example 1 is more than 0.3%, though therefore
So produced martensite hardness is higher during drop stamping heating and thermal insulation and cooling, but plasticity is but not
It is enough so that the elongation of comparative example 1 is only 12.9%.
Understood with reference to the content of table 2 and table 3, because the Mn contents of comparative example 2-2 are low, cause its Ovshinsky
Body temperature is (>=800 DEG C) higher, and drop stamping heating and thermal insulation temperature is only 780 DEG C, incomplete austenite
Change, Martensite Volume Fraction is not enough, and low strength, plasticity is also not enough, therefore the tension of comparative example 2-2 is strong
Degree is only 1280MPa, fails to reach 1500MPa ranks.
Understood with reference to table 1, table 2 and the content of table 3, comparative example 2-1 is drop stamping steel of the prior art
The elongation of 22MnB5, comparative example 2-1 is only 7.2%, and its auto parts and components for being far below embodiment is stretched
Rate long, illustrates that the plasticity of comparative example 2-1 is inferior to the plasticity of embodiment.In addition, the drop stamping of comparative example 2-1
Heating and thermal insulation temperature is up to 930 DEG C, the thermal energy consumption of its thermal energy consumption to be needed significantly larger than embodiment.
In sum, technical scheme is joined by controlling rational composition design and the technique of optimization
Number, in the case of substantially without expensive alloy element, by carbon and the composition design of manganese element,
Manufactured out using martensitic traoformation induced plastic effect (TRIP effects) and have high intensity and extension high concurrently
The auto parts and components of rate.There is the auto parts and components excellent strong plasticity to match, and be conducive to improving vehicle structure
The anticollision performance of part, thus significantly lifts the security performance of vehicle body.
In addition, the manufacture method of low temperature drop stamping auto parts and components of the present invention can apply in routine
Automobile board assembly line and drop stamping production line on.
Additionally, being based on technical scheme, the heating and thermal insulation temperature of drop stamping reduces more than 100 DEG C,
Thermal energy consumption is significantly reduced, industrial efficiency is improve, production cost has been saved.
The microstructure of the low temperature drop stamping auto parts and components of Fig. 1 display embodiment of the present invention 4-2.
From figure 1 it appears that the microstructure of the auto parts and components is martensite+austenite+ferrite,
Wherein, the Phase Proportion of austenite is about 15% (non-transformed austenite is about after XRD measurement tension failures
0.5%, therefore 14.5%) Phase Proportion of typical austenite is about, the Phase Proportion of martensite is about 80%, remaining
It is ferrite, the crystallite dimension of auto parts and components austenite is 0.2-3 μm.
It should be noted that listed above is only specific embodiment of the invention, it is clear that the invention is not restricted to
Above example, the similar change for having many therewith.If those skilled in the art discloses from the present invention
Content all deformations for directly deriving or associating, protection scope of the present invention all should be belonged to.
Claims (18)
1. a kind of low temperature drop stamping auto parts and components, it is characterised in that its microstructure is martensite+austenite
+ ferrite, the chemical element mass percent of the low temperature drop stamping auto parts and components is：
C：0.1%~0.3%, Si：0.1%~2.0%, Mn：3%~7%, Al：0.01%~0.06%,
P≤0.02%, S≤0.02%, N≤0.005%, balance of Fe and other inevitable impurity.
2. low temperature drop stamping auto parts and components as claimed in claim 1, it is characterised in that the austenite
Phase Proportion is 5%~30%.
3. low temperature drop stamping auto parts and components as claimed in claim 2, it is characterised in that the austenite bag
Typical austenite is included, the Phase Proportion that typical austenite accounts for whole microstructures is 5%~20%.
4. low temperature drop stamping auto parts and components as claimed in claim 3, it is characterised in that wherein ferritic
Phase Proportion is≤20%.
5. low temperature drop stamping auto parts and components as claimed in claim 1, it is characterised in that its crystallite dimension
≤5μm。
6. low temperature drop stamping auto parts and components as claimed in claim 1, it is characterised in that its chemical element is also
With 0 ＜ Nb≤0.5%, 0 ＜ V≤1.0%, 0 ＜ Ti≤0.5% at least one.
7. low temperature drop stamping auto parts and components as claimed in claim 1, it is characterised in that Si contents are
0.3%~1.5%.
8. low temperature drop stamping auto parts and components as claimed in claim 1, it is characterised in that Mn contents are
5%~7%.
9. low temperature drop stamping auto parts and components as claimed in claim 1, it is characterised in that its tensile strength >=
1500MPa, and its elongation >=15%.
10. low temperature drop stamping auto parts and components as described in any one in claim 1-9, it is characterised in that
Its chemical element content meets：24.2C-2.8Si+Mn-10.1Al >=2, C, Si, Mn in formula and
Al represents the mass percent of respective element respectively.
The drop stamping work of the 11. low temperature drop stamping auto parts and components as described in any one in claim 1-10
Skill, it is characterised in that：The heating and thermal insulation temperature of drop stamping be 700~850 DEG C, soaking time be 2~
10min, to complete complete austenitizing.
12. drop stamping techniques as claimed in claim 11, it is characterised in that protected using nitrogen in heating furnace
Shield carries out heating and thermal insulation, and it is 700~850 DEG C, the soaking time to control the heating and thermal insulation temperature
It is 2~10min, to complete complete austenitizing；Then blank is put into hot stamping die is carried out
Hot press-formed, the drop stamping dwell time is 3~15 seconds, and stamping press is 300~1000 tons；Heat punching
After the completion of pressing formation, blank is cooled down in hot stamping die.
The manufacture method of the 13. low temperature drop stamping auto parts and components as described in any one in claim 1-10,
It includes step successively：
(1) smelt；
(2) cast；
(3) hot rolling；
(4) anneal；
(5) pickling；
(6) it is cold rolling；
(7) the heating and thermal insulation temperature of drop stamping, wherein drop stamping is 700~850 DEG C, soaking time
It is 2~10min, to complete complete austenitizing.
14. manufacture methods as claimed in claim 13, it is characterised in that in the step (3), will cast
Base be heated to 1100~1250 DEG C after controlled rolling, start rolling temperature be 950~1150 DEG C, finishing temperature
It it is 750~900 DEG C, coiling temperature is 500~850 DEG C, is subsequently cooled to room temperature, makes microstructure
It is martensitic structure.
15. manufacture methods as claimed in claim 13, it is characterised in that in the step (4), annealing
Temperature is 550~850 DEG C, and the time is not less than 1h, in the microstructure obtained after annealing containing 20~
40% austenite.
16. manufacture methods as claimed in claim 13, it is characterised in that cold rolling in the step (6)
Reduction ratio >=35%.
17. manufacture methods as claimed in claim 13, it is characterised in that cold rolling in the step (6)
Also carry out afterwards it is cold rolling after annealing steps, annealing temperature be 400~750 DEG C, annealing time is not less than
60s。
18. manufacture methods as claimed in claim 13, it is characterised in that in the step (7), are adding
In hot stove using nitrogen protection carry out heating and thermal insulation, control the heating and thermal insulation temperature be 700~
850 DEG C, the soaking time is 2~10min, to complete complete austenitizing；Then blank is put
To enter carry out in hot stamping die hot press-formed, the drop stamping dwell time is 3~15 seconds, and stamping press is
300~1000 tons；After the completion of hot press-formed, blank is cooled down in hot stamping die.
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| CN201511009922.XA CN106906420A (en) | 2015-12-29 | 2015-12-29 | A kind of low temperature drop stamping auto parts and components, its drop stamping technique and its manufacture method |
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| CN110832100A (en) * | 2017-06-27 | 2020-02-21 | 现代制铁株式会社 | Steel material for tailor welded blank and method for manufacturing hot stamped part using the same |
| JP2021501833A (en) * | 2017-11-02 | 2021-01-21 | イージーフォーミング・スティール・テクノロジー・カンパニー・リミテッドＥａｓｙｆｏｒｍｉｎｇ Ｓｔｅｅｌ Ｔｅｃｈｎｏｌｏｇｙ Ｃｏ．， Ｌｔｄ． | Steel used for hot stamping, hot stamping methods and molded components |
| EP3789509A4 (en) * | 2018-04-28 | 2021-11-10 | Ironovation Materials Technology Co., Ltd. | Steel for hot stamping, hot stamping process, and hot stamped component |
| CN113798368A (en) * | 2021-08-25 | 2021-12-17 | 成都飞机工业（集团）有限责任公司 | Curved panel forming method |
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| JP2021501833A (en) * | 2017-11-02 | 2021-01-21 | イージーフォーミング・スティール・テクノロジー・カンパニー・リミテッドＥａｓｙｆｏｒｍｉｎｇ Ｓｔｅｅｌ Ｔｅｃｈｎｏｌｏｇｙ Ｃｏ．， Ｌｔｄ． | Steel used for hot stamping, hot stamping methods and molded components |
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| EP3789509A4 (en) * | 2018-04-28 | 2021-11-10 | Ironovation Materials Technology Co., Ltd. | Steel for hot stamping, hot stamping process, and hot stamped component |
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| CN113798368A (en) * | 2021-08-25 | 2021-12-17 | 成都飞机工业（集团）有限责任公司 | Curved panel forming method |
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Application publication date: 20170630 |