CN101743335B - Cold-work die steel and dies for cold pressing - Google Patents
Cold-work die steel and dies for cold pressing Download PDFInfo
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- CN101743335B CN101743335B CN2009800002926A CN200980000292A CN101743335B CN 101743335 B CN101743335 B CN 101743335B CN 2009800002926 A CN2009800002926 A CN 2009800002926A CN 200980000292 A CN200980000292 A CN 200980000292A CN 101743335 B CN101743335 B CN 101743335B
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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
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
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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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
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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
- C21D7/00—Modifying the physical properties of iron or steel by deformation
- C21D7/13—Modifying the physical properties of iron or steel by deformation by hot working
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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
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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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
- C21D2211/004—Dispersions; Precipitations
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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
- C21D7/00—Modifying the physical properties of iron or steel by deformation
- C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
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Abstract
The present invention provides a cold-work die steel useful as a material of dies for cold pressing, which has basic properties such as hardness, toughness and dimensional change by heat treatment, and besides, which causes no problem in terms of machined surface roughness and cutting tool life, and also its dies for cold pressing. The invention relates to a cold-work die steel comprising: 0.5 to 0.7 mass % of C; 5.0 to 7.0 mass % of Cr; 0.5 to 2.0 mass % of Si; 0.1 to 2.0 mass % of Mn; 0.001 to 0.010 mass % of Al; 0.25 to 1.00 mass % of Cu; 0.25 to 1.00 mass % of Ni; 0.5 to 3.0 mass % of Mo+0.5W; 0.5 mass % or less of V; 0.05 mass % or less of P; 0.1 mass % or less of S; 0.005 mass % or less of O, wherein the following requirements are satisfied: [C][Cr]<=4; FP=[Si]/5+[Cr]/5+2[Mo]+[W]+2[V]+10[Al]<=5.0; and AP=[Mn]+3([Cu]+[Ni])<=2.5, and also relates to a die for cold pressing which is manufactured by using the cold-work die steel.
Description
Technical field
The present invention relates to cold-work die steel and mould is used in cold stamping, this cold-work die steel is useful with the starting material of mould as the cold stamping of using when drawing (punching, bending, deep-draw, side cut etc.) automotive sheet or household electrical appliances are with steel plate etc. down at low temperature etc.
Background technology
Be used for automotive sheet or household electrical appliances with the cold stamping of drawings such as steel plate with the high strength of mould along with steel plate, just seeking to improve its life-span.Especially, concerning automotive sheet, consider environmental problem, in order to improve the specific fuel consumption of automobile, adopt the above high tensile steel plate of tensile strength 590MPa mostly, it needs and will increase day by day from now in anticipation.
When this high tensile steel plate of drawing; Because having implemented the surface-treated cold stamping damages with the surperficial epithelium of mould in early days; Thereby sintering phenomenon takes place when being known as mould bonding or agglutinating drawing, and cold stamping increases with very short problem of the life-span of the mould of mould.
Cold stamping is handled and is made through the surface of the cold-work die steel that becomes mother metal being implemented hard film with mould.Usually, become that the cold-work die steel of mother metal is annealed, cut and Q-tempering handle such operation and make.
As cold-work die steel, all the time, the alloy tool steel of the high Cr of high C such as widespread use JIS SKD11 or further improved the rapid tool steels such as JIS SKH51 of wearability.Concerning these TS, seek to improve hardness through the precipitation-hardening of Cr class carbide and Mo, W, V class carbide.And, also will be through reducing alloying elements such as C that JIS SKH51 contains, Mo, W, V, the low alloy high-speed tool steel that is known as the mold high speed steel that has improved toughness, wearability two sides is used for cold-work die steel.In addition, as having realized the further technology of improving these cold-work die steel characteristics, in the technology that the technology or the patent documentation 2 of patent documentation 1 record are put down in writing, motion is arranged also.
In addition; Patent documentation 2 discloses a kind of alloy tool steel; It to be comparing with present mold high speed steel, even reduce quenching temperature, characteristics such as the hardness after the thermal treatment, toughness also obtain with present mold high speed steel be purpose with the characteristic of degree; Under Annealed Strip, have the tissue of the M23C6 type compound 2~5vol% of generation, and have any the Q-tempering tissue at least that disperses to separate out MC type carbide and M6C type carbide.
Patent documentation 1: (Japan) spy opens the 2006-169624 communique
Patent documentation 2: (Japan) spy opens the 2004-169177 communique
Cold stamping is handled and is made through the surface of the cold-work die steel that becomes mother metal being implemented hard film with mould.Handle as this hard film, the CVD that has the TD that forms the epithelium that is made up of VC through thermodiffusion to handle, forms mainly the epithelium that is made up of TiC handles, forms the PVD processing of the main epithelium that is made up of TiN etc.The situation that these hard films are handled according to mould user and mfr suits to adopt.Therefore, seek to develop a kind of cold-work die steel, it can be handled by corresponding any hard film.In addition, certainly, mould is used in cold stamping, also sought to guarantee hardness and toughness, these fundamental characteristics of heat treatment deformation.
In addition, with mould, also there is the problem of pulling in the cut in cold stamping.When pulling, cutting finished surface roughness increases, so the difficulty of the grinding operation after the thermal treatment, and causes the minimizing of die life.In addition, the cutting tool life-span also shortens, and manufacturing cost increases.In order to address these problems, need inhibition to be situated between at thing (Al as the Al class of the occurrence cause of problem
2O
3, AlN) separate out, but when reducing when separating out the Al class and be situated between Al content, might descend to decrease of hardness, toughness on the contrary at the element of thing, these fundamental characteristics such as increase of heat treatment deformation amount produce detrimentally affects.Thereby expectation exploitation is a kind of has not only guaranteed these fundamental characteristics, and cutting finished surface roughness and cutting tool aspect the life-span cold stamping also out of question use mould.
Summary of the invention
The present invention develops for solving these present problems; It uses mould to be problem so that cold-work die steel and cold stamping thereof to be provided; This cold-work die steel not only possesses hardness, toughness, these fundamental characteristics of seeking of heat treatment deformation; And can handle by corresponding various hard films, in addition, as useful at the starting material of cutting finished surface roughness and cutting tool cold punching die also out of question aspect the life-span.
Below represent aim of the present invention:
Cold-work die steel is characterized in that, contains
C:0.5~0.7 quality %;
Cr:5.0~7.0 quality %;
Si:0.5~2.0 quality %;
Mn:0.1~2.0 quality %;
Al:0.001~0.010 quality %;
Cu:0.25~1.00 quality %;
Ni:0.25~1.00 quality %;
N:0.003~0.025 quality %;
P: greater than 0 and below 0.05 quality %;
S: greater than 0 and below 0.1 quality %;
O: greater than 0 and below 0.005 quality %; And
At least a among Mo and the W,
Surplus is iron and unavoidable impurities,
And satisfy 0.5≤[Mo]+0.5 * [W]≤3.0 and the such prerequisite in [C] * [Cr]≤4,
And FP (parameter that the ferritic generting element forms) satisfies [Si]/5+ [Cr]/5+2 * [Mo]+[W]+2 * [V]+10 * such prerequisite in [Al]≤5.0,
AP (parameter that the austenite generting element forms) satisfies [Mn]+3 * such prerequisite in ([Cu]+[Ni])≤2.5,
Wherein, [] in the following formula represented the content (quality %) of each element.
Cold-work die steel according to [1] record wherein, also contains V: greater than 0 and below 0.5 quality %.
According to the cold-work die steel of [1] or [2] record, wherein, also contain and add up to greater than 0 and below 0.5 quality %, be selected from least a element in the group that Ti, Zr, Hf, Ta, Nb constitute.
According to the cold-work die steel of each record in [1]~[3], wherein, also contain Co: greater than 0 and below 10 quality %.
Mould is used in cold stamping, wherein, through the cold-work die steel of each record in [1]~[4] is processed, and implements surface treatment and makes.
Through cold-work die steel of the present invention being used as the starting material of cold stamping with mould; Not only possess hardness, toughness, the such fundamental characteristics of seeking of heat treatment deformation; And can handle by corresponding various hard films; And, can access cutting finished surface roughness and cutting tool aspect the life-span cold stamping also out of question use mould.In addition, use cold stamping that this cold-work die steel obtains, especially can preferably use with the shaping usefulness of mould as the high tensile steel plate more than the tensile strength 590MPa.
Description of drawings
Fig. 1 is the figure of the principle of the TiN epithelium damage that causes of expression Cr class carbide; (a) be the longitudinal section of the original cold stamping of expression with mould; (b) being that the expression cold stamping with the TiN epithelium of mould the longitudinal section of the state of crackle has taken place, (c) is to represent that this crackle becomes the longitudinal section of the state that starting point TiN epithelium taken place to peel off;
Fig. 2 is the explanatory view that is illustrated in the pendulum impact test sheet that uses in the mensuration of pendulum impact value of embodiment;
Fig. 3 is the explanatory view of the heat-treat condition of expression when implementing thermal treatment to handle the test body that uses in the mensuration of deflection in the embodiment maximum heat.
Description of reference numerals
1 cold-work die steel
2 TiN epitheliums
3 Cr class carbide
4 crackles
Embodiment
Below, based on embodiment, the present invention is done further detailed description.
At first, the present inventor causes established TiN epithelium to damage, take place the agglutinating reason with mould having carried out studying with keen determination to present JIS SKD11 and mold high speed steel being used for raw-material cold stamping because of PVD handles.
The result of research is, finds that TiN epithelium generation agglutinating reason is to become the thick Cr class carbide that the cold-work die steel of mother metal generates, and promptly this Cr class carbide becomes starting point and bonds.Because of this Cr class carbide causes the principle of TiN epithelium damage as shown in Figure 1.
At first, shown in Fig. 1 (a), prepare to form the cold stamping of TiN epithelium 2 and use mould through the surface of the cold-work die steel 1 that becomes mother metal being implemented hard film is handled and on the surface.This cold-work die steel 1 is separated out thick Cr class carbide 3 on the surface as the cold-work die steel 1 of mother metal when JIS SKD11 and mold high speed steel are formed as starting material.When carrying out drawing with mould, shown in Fig. 1 (b),, on TiN epithelium 2, crack 4 when being formed thing when the direction of arrow is slided with this cold stamping.The position that Cr class carbide 3 is arranged is separated out for the mother metal below TiN epithelium 2 in the position that this life crackle 4 produces.And when slip was formed thing, shown in Fig. 1 (c), its crackle 4 became starting point, on TiN epithelium 2, peels off, thereby bonds.
As above explain saidly, the reason that TiN epithelium bonding takes place is a Cr class carbide.The present inventor has found can prevent peeling off of TiN epithelium through suppressing the generation of this Cr class carbide, and can suppress to take place very short such problem die life.
The generation of the thick Cr class carbide 3 of separating out for the surface that is suppressed at the cold-work die steel that becomes mother metal and prolong the life-span of handling the TiN epithelium that forms through PVD is as long as reduce C content and Cr content in the steel.But, when too reducing C content, be not easy on the surface of cold-work die steel, to form TD and handle the VC epithelium of formation or the TiC epithelium that CVD handles formation.So; The content that the present invention not only establishes C is that the content of 0.5~0.7 quality %, Cr is 5.0~7.0 quality %; And stipulate the long-pending of these content; Thus, do not separate out thick Cr class carbide 3 on the surface of cold-work die steel, and can form needed fully thick VC epithelium or TiC epithelium.
In addition, the present invention has also stipulated parameter that is formed by Si, Cr, Mo, W, V, these ferritic generting elements of Al and the parameter that is formed by Mn, Cu, these austenite generting elements of Ni.
When the total content of Si, Cr, Mo, W, V, these ferritic generting elements of Al was too much, the hardness of cold-work die steel and flexible balance were destroyed, and cut finished surface precision also worsens.So; In the present invention, will be by ferritic generting element predetermined parameter (FP) formulation, and the total content of regulation ferritic generting element is for satisfying its numerical expression; Make the hardness and the flexible balance of cold-work die steel good thus, and also improved cut finished surface precision.
In addition, when the total content of Mn, Cu, these austenite generting elements of Ni is too much, increase because retained austenite increases the deviation that causes the heat treatment deformation amount, shorten the life tools when cutting simultaneously.So, in the present invention, will be by austenite generting element predetermined parameter (AP) formulation; And the total content of regulation austenite generting element is for satisfying its numerical expression; Reduce the retained austenite in the steel thus, reduce the deviation of heat treatment deformation amount, the life tools when prolonging cutting simultaneously.
Below, the scope of the content of the chemical ingredients in the relevant cold-work die steel of the present invention limits reason, and each element is all carried out detailed explanation.In addition, the % that puts down in writing in this specification sheets all representes quality.
C:0.5~0.7%
C guarantees hardness and wear resistance, and also helps suppressing HAZ remollescent element.In addition, when forming TD on the surface of mold base material and handling the VC epithelium that forms or CVD and handle the such carbide epithelium of the TiC epithelium that forms, also exist when the content of C after a little while, problems such as the thickness attenuation of epithelium.Consider these, establish the following of C content that is used for effectively bringing into play above-mentioned effect and be limited to 0.5%.In addition, its lower limit is preferably 0.55%.Wherein, when its content is superfluous, generate thick Cr class carbide, handle the TiN epithelium that forms through PVD and peel off easily.In addition, when the content of C was superfluous, retained austenite increased, and can not obtain desirable hardness when at high temperature not carrying out temper, in addition, after temper, expands etc., and distortion strengthens.And, when C content is superfluous, toughness is also caused detrimentally affect.Thereby, establish C content on be limited to 0.7%.In addition, its upper limit is preferably 0.65%.
Cr:5.0~7.0%
Cr is the useful element of the hardness of guaranteeing defined.Say that at length when the content of Cr was very few, hardenability was not enough, generates a part of bainite, so decrease of hardness, can not guarantee wearability.In addition, Cr is the useful element of the erosion resistance of guaranteeing mould.So, establish the following of Cr content and be limited to 5.0%.And its lower limit is preferably 5.5%.Wherein, when its content was superfluous, thick Cr compounds generated in a large number, handled the TiN epithelium that forms through PVD and peeled off easily.In addition, when the content of Cr is superfluous,, the contraction after the thermal treatment descends owing to making the weather resistance of hard film.And, when the content of Cr is superfluous, also toughness is produced detrimentally affect.So, establish Cr content on be limited to 7.0%.And its upper limit is preferably 6.5%.
Si:0.5~2.0%
Si is useful as the deoxidant element of system during steel, is to help the raising of hardness and the element that machinability is guaranteed.In addition, Si suppresses the martensitic temper softening of mould, and is softening useful to suppressing HAZ.For the effectively such effect of performance, establish the following of Si content and be limited to 0.5%.Its content is preferably more than 1.0%, more preferably more than 1.2%.Wherein, when its content was superfluous, toughness descended.And segregation increases, and the distortion after the thermal treatment increases.Thereby, establish Si content on be limited to 2.0%.Its content is preferably below 1.85%.
Mn:0.1~2.0%
Mn is an element of guaranteeing that hardenability is useful.Wherein, when its content was superfluous, retained austenite increased, and therefore, when at high temperature not carrying out temper, can not get desirable hardness, and in addition, toughness also descends.Consider these, the content of Mn is defined in 0.1~2.0% scope.The lower limit of Mn content is preferably 0.15%, and its upper limit is preferably 1.0%, and more preferably 0.5%, be preferably 0.35% especially.
Al:0.01~0.010%
Al is as the useful element of reductor.Wherein, when content was discontented with 0.001%, its effect can not fully obtain.Therefore, establish the following of Al content and be limited to 0.001%.Its lower limit is preferably 0.002%.On the other hand, as Al
2O
3And the Al class of thick AlN is situated between and becomes the reason of pulling in the cutting at thing, reduces cutting finished surface precision, therefore establish Al content on be limited to 0.010%.Its upper limit is preferably 0.008%.
Cu:0.25~1.00%
Cu is the essential element of the hardness raising of the precipitation strength that realizes ε-Cu, and it is softening also to help suppressing HAZ.Wherein, when its content was superfluous, toughness descended, and forge crack takes place easily.So, establish Cu content on be limited to 1.00%.And its upper limit is preferably below 0.80%.In addition, the following of Cu content is limited to 0.25%.And its lower limit is preferably 0.30%.
Ni:0.25~1.00%
Ni is used to realize Ni
3The hardness of the precipitation strength of compound improves essential element between Al-Ni metalloids such as Al, and it is softening also to help suppressing HAZ.In addition, Ni through with Cu and usefulness, suppress the surplus of Cu and add the red brittleness that causes, also can prevent teacher of the forging's crackle.Wherein, when its content was superfluous, retained austenite increased, and when at high temperature not carrying out temper, can not guarantee the hardness of defined, in addition, after thermal treatment, expands.In addition, when the content of Ni was superfluous, toughness also descended.Consider these, the content of Ni is defined in 0.25~1.00% scope.The lower limit of Ni content is preferably 0.30%, and its upper limit is preferably 0.80%.
N:0.003~0.025%
N and Al form the AlN precipitate jointly, and the coarsening when preventing to quench is for realizing good flexible important element.In order to realize good toughness, establish the following of N content and be limited to 0.003%.Its lower limit is preferably 0.004%.In addition, establish N content on be limited to 0.025%.Its upper limit is preferably 0.17%.
Mo+0.5W:0.5~3.0%
Mo and W all are except that forming M3C type carbide, M6C type carbide, also form between the Ni3Mo metalloid compound etc., help the element of precipitation strength.Wherein, when these content are superfluous, remove superfluous generations such as above-mentioned carbide, cause outside the toughness decline, the distortion after the thermal treatment also increases.So Mo in the time of will using Mo+0.5 * W formula and the total content of W are defined in 0.5~3.0% scope.The independent content of Mo also is preferably 0.5~3.0% scope.In addition, the independent content of W is preferably below 2.0% and (comprises 0%).That is, Mo is that necessary element, W are for selecting element.Wherein, the lower limit of the independent content of W more preferably 0.02%.In addition, the lower limit of the independent content of Mo more preferably 0.7%, the upper limit more preferably 2.5%.The lower limit of the independent content of W more preferably 0.05%, the upper limit more preferably 1.5%.
P: greater than 0 and below 0.05%
P is the element that in dissolving raw material, exists inevitably, is to influence the flexible element.Therefore, establish P content on be limited to 0.05%.Its upper limit is preferably 0.02%.And the content of preferred P is few more good more, but contains inevitably, therefore, in fact, is limited to about 0.005% under it.
S: greater than 0 and below 0.1%
S is the element to guaranteeing that machinability is useful.From guaranteeing the viewpoint of machinability, recommend to be preferably more than 0.002%, the content more than 0.004% more preferably.But, when its content was superfluous, welding crack took place.So, establish S content on be limited to 0.1%.The upper limit of S content is preferably 0.07%, and more preferably 0.05%, be preferably 0.025% especially.
O: greater than 0 and below 0.005%
O is contained in the element that dissolves steel grade, and inevitable the is contained in the steel.When the content of O is high, react with Si, Al etc., form oxide-based Jie at thing.Therefore, establish O content on be limited to 0.005%.Its upper limit is preferred 0.003%, and more preferably 0.002%.And the content of preferred O is few more good more, but owing to contain inevitably, so in fact be limited to about 0.0005% under it.
The present invention also will satisfy each numerical expression of having explained the front and be made as necessary prerequisite.In addition, [] shown in each numerical expression represented the content (quality %) of each element.
[C]×[Cr]≤4
Above-mentioned numerical expression is for to suppress the numerical expression that purpose is set that is generated as of thick Cr class carbide.When amassing of C content and Cr content surpassed 4, the weather resistance of hard film descended, and in addition, the distortion after the thermal treatment increases.In addition; From the generation that suppresses thick Cr class carbide and the viewpoint of the distortion after suppressing thermal treatment; Preferred C content and Cr content long-pending as much as possible little, but during the above-mentioned effect of playing when the interpolation of also considering effectively to bring into play C and Cr etc., this lower limit that amasss preferably probably is 0.8.
FP=[Si]/5+[Cr]/5+2×[Mo]+[W]+2×[V]+10×[Al]≤5.0
Above-mentioned numerical expression is the numerical expression with the total content parameter regulation of Si, Cr, Mo, W, V, these ferritic generting elements of Al.When this parameter (FP) greater than 5.0 the time, the hardness of cold-work die steel and flexible balance are destroyed, the surface accuracy accomplished of cut also worsens simultaneously.This parameter (FP) is more preferably below 4.8.The FP value 2.11 that the lower value of the element that must be contained by cold-work die steel of the present invention such as Si, Cr is confirmed is the lower value of this parameter (FP) of reality.
AP=[Mn]+3×([Cu]+[Ni])≤2.5
Above-mentioned numerical expression is the numerical expression with the total content parameter regulation of Mn, Cu, these austenite generting elements of Ni.When this parameter (AP) greater than 2.5 the time, retained austenite increases, the deviation of heat treatment deformation amount increases, shorten the life tools when cutting simultaneously.This parameter (AP) is more preferably below 2.3.Be actually the lower value of this parameter (AP) by the definite AP value 1.6 of the lower value of Mn, Cu, Ni.
The prerequisite of the basal component of relevant cold-work die steel of the present invention as stated.Surplus contains iron and unavoidable impurities.As impurity, for example can enumerate Sn, Pb etc.In addition, in the present invention, be purpose with the characteristic of improving other, can also contain following selection component.
V:0~0.5%
V helps except that forming carbide such as VC hardness improves, to suppressing the softening effective elements of HAZ.In addition, implement on mother metal surface gas nitriding, salt dissolve nitrogenize, when nitriding treatment such as plasma nitrided forms diffusion hardened layer, for to the raising of surface hardness and the intensification effective elements of case depth.For the effectively such effect of performance, the content of V preferably adds general more than 0.05%.Wherein, when its content was superfluous, solid solution C measured decline, causes the decrease of hardness as the martensitic stucture of parent phase, and in addition, toughness descends.So, establish V content on be limited to 0.5%.The upper limit of V content is preferably 0.4%, and more preferably 0.3%.
Be selected from least a element in the group that Ti, Zr, Hf, Ta, Nb constitute: add up to below 0.5%
These elements are nitride forming element, help nitride and AlN fine decentralized of these elements, consequently, are thickization that prevents crystal grain and help the element that toughness improves.For the effectively above effect of performance, preferably probably establish Ti and be more than 0.01%, Zr is more than 0.02%, Hf is more than 0.04%, Ta is more than 0.04%, Nb contains more than 0.02%.Wherein, when these total content was superfluous, solid solution C measured decline, causes martensitic decrease of hardness.So the total content of establishing these elements is below 0.5%.The total content of these elements is preferably below 0.4%, more preferably below 0.3%.In addition, these elements both can contain separately, also can merge two or more containing.
Below the Co:10%
Co improves the Ms point and to the minimizing effective elements of retained austenite, thus, can improve hardness.Should act in order effectively to bring into play, the content of preferably establishing Co probably is more than 1%.Wherein, when its content is superfluous, will cause risings such as cost, and therefore establish and be limited to 10%.The upper limit of Co content is preferably 5.5%.At this, so-called Ms point is one of transformation temperature (when temperature, the metamorphosis that phase change takes place spreads all over the TR generation, the temperature of abnormal beginning or the temperature that finishes), and promptly during refrigerative, austenite begins the meaning to the abnormal temperature of martensite.
The cold-work die steel of the prerequisite of above-mentioned record is satisfied in use, makes cold stamping and uses mould.The example of this cold stamping with the method for manufacture of mould described.For example, after dissolving system cold-work die steel of the present invention, carry out after the heat forged; Anneal (for example, about 700 ℃ keep 7 hours after, be as cold as about 400 ℃ with the average cooling rate stove of about 17 ℃/hr after; Put cold) softening after, carry out roughing through cut etc. and become after the shape of regulation, under 950~1150 ℃ temperature, carry out quench treatment; Also under 400~530 ℃, carry out temper, give desirable hardness, make cold stamping thus and use mould.
Embodiment
Below, enumerate embodiment, the present invention more specifically is described, but the present invention is not limited in these examples.
In the present embodiment; The steel grade (the JIS SKD11 that No.1 uses as cold-work die steel all the time) that 26 kinds of one-tenth of meter of record are grouped in the table 1; After vacuum induction dissolving stove dissolves the blank of system 150kg, be heated to 900~1150 ℃, forge the plate of 40mmT * 75mmW * about 2000mmL; Thereafter, the average cooling rate with about 60 ℃/hr has carried out Xu Leng.After being cooled to the temperature below 100 ℃, be heated to about 850 ℃ once more, the average cooling rate with about 50 ℃/hr has carried out Xu Leng (annealing) again.Use the annealed material that obtains as stated, the various tests below having carried out.
(1) mensuration of highest hardness
Cut out the test film of 20mmT * 20mmW * 15mmL size from above-mentioned annealed material; Use test film as measurement of hardness, this test film has been implemented according to quench treatment (1030 ℃ of down heating 120 minutes), air cooling, temper (keeping 180 minutes down at 450~520 ℃) and put cold processing in sequence.Utilize Vickers hardness tester (the specification AVK of AKASHI society system, loading 5kg), be determined at the hardness when changing tempering temperature in 450~520 ℃ of scopes, and studied its highest hardness.In this test, the test film of establishing more than the highest hardness 650HV that obtains through mensuration is qualified.Its test-results of table 2 expression.
(2) mensuration of pendulum impact value (flexible mensuration)
To the thermal treatment of above-mentioned annealed material, specifically, implemented according to quench treatment (1030 ℃ of down heating 120 minutes), air cooling, temper (keeping 180 minutes down) and put cold processing in sequence at 450~520 ℃.Then, the test film that cuts out the R notch with 10mmR shown in figure (2) is measured with test film (pendulum impact test sheet) as toughness.Utilize this test film to implement pendulum impact test, measured the absorption energy under the room temperature (pendulum impact value).Each steel grade is respectively chosen three pendulum impact test sheets, with these MVs as the pendulum impact value.In this test, the test film of establishing more than the pendulum impact value 20J that obtains through mensuration is qualified.Its test-results of table 2 expression.
(3) investigation of cutting finished surface roughness
With above-mentioned annealed material is the test body, accomplishes processing through ball end mill, has measured cutting finished surface roughness.Test conditions is described below.
Machinery: MORI (BT40,5.5kw)
Instrument: the SRFH30S32M φ of Mitsubishi 30
Section: the SRFH30 VP10MF φ of Mitsubishi 30
Outstanding length: 118mm
Cutting direction: up cut
Cutting speed: 250mm/min
Speed of feed: 0.31mm/rev
Incision: Ad0.3mm, Rb0.7mm
Machining oil: do not have (blowing)
Processing distance: 257.1m
Cutting finished surface roughness Ra is a MV of measuring the value that the 10mm length range at five positions of test body obtains.In this test, the test body of establishing the cutting finished surface roughness Ra that obtains through test and being below the 0.40mm is qualified.Its test-results of table 2 expression.
(4) judgement of smear metal life tools
With above-mentioned annealed material is the test body, carries out high roughing of carrying stapling machine, has investigated the life-span of cutting tool.Test conditions is described below.
Machinery: OKK (BT50,7.5kw)
Instrument: the AJX148R503SA42S φ of Mitsubishi 50
Section: JOMW140520ZDSR-FT VP15TF
Cutting speed: 10mm/min
The amount of feed: 1.0mm/rev
Incision: Ad1mm, Rb35mm
Outstanding length: 80mm
Machining oil: do not have (air blowing)
Judging service life: tool wear, hinder sword
The relevant cutting tool life-span; If be life-span of the cutting tool of raw-material test body (No.1) when carrying out roughing during for " 1 " in order to JIS SKD11, the life-span of utilizing the cutting tool when respectively testing body and carrying out roughing is through for being that what of life-span of the cutting tool of raw-material test body (No.1) when carrying out roughing are doubly judged with SKD11.To cut instrument be qualified if this decision content is the trial cut more than 4.0.Its test-results of table 2 expression.
(5) maximum heat is handled the mensuration of deflection
From above-mentioned annealed material, each annealed material is cut out six of the pieces of 40mmT * 75mmW * 100mmL, handle the test body that deflection is measured usefulness as maximum heat, this test body has been implemented thermal treatment under condition shown in Figure 3.Maximum heat is handled deflection and is obtained by the dimensional change amount before and after the thermal treatment of six test bodies.Respectively each test body is obtained the dimensional change amount of orthogonal three directions (x direction, y direction, z direction), the numerical value of establishing the maximum in the absolute value of 3 directions * 6 that obtain is that maximum heat is handled deflection.In this test, it is qualified establishing the test body of this maximum heat processing deflection below 0.08.Its test-results of table 2 expression.
[table 1]
[table 2]
Shown in table 1 and table 2 record; As long-pending, parameter that the ferritic element forms by the content of the content of the content of each chemical ingredients, C and Cr, the parameter that forms by the austenite generting element all satisfy the invention example of prerequisite of the present invention No.7~9,11,14~20 highest hardness, pendulum impact value, to cut finished surface roughness, cutting tool life-span, maximum heat processing deflection all be in the scope of qualification determination benchmark.Relative therewith, as a prerequisite of the present invention also No.1 of ungratified comparative example~6,10,12~13,21~26 minimum one depart from the qualification determination benchmark, have that some is improper.
No.1~6,10,12~13,21~26 comparative example depart from one or more the prerequisite in the above-mentioned prerequisite of the present invention, and some is improper thereby have, and the example of establishing each the prerequisite characteristic with above-mentioned record is a comparative example.Below, the comparative example of stipulating among the present invention that meets each prerequisite is described.
The too much comparative example of C content and Cr content is No.1 and No.2, otherwise the very few comparative example of C content and Cr content is No.3 and No.4.The too much comparative example of these content, very few its pendulum impact value (toughness) of comparative example, cutting finished surface roughness, cutting tool life-span, maximum heat handle deflection all or some all depart from the qualification determination benchmark.
The too much comparative example of Si content is No.21, otherwise the very few comparative example of content is No.1.Especially, superfluous its toughness of No.21 of its content descends greatly, and the pendulum impact value departs from the qualification determination benchmark.In addition, though be in the scope of qualification determination benchmark, the deformation ratio after the thermal treatment is bigger.
The too much comparative example of Mn content is No.22.The toughness of this comparative example descends greatly, and the pendulum impact value departs from the qualification determination benchmark.In addition, cutting tool life-span, maximum heat are handled the scope that deflection also departs from the qualification determination benchmark.
The too much comparative example of Al content is No.10, otherwise very few comparative example is No.6.Crackle takes place man-hour accomplishing through ball end mill to add in the too much comparative example No.10 of Al content, and cutting finished surface precision worsens.In addition, very few its pendulum impact value of comparative example No.6 departs from the qualification determination benchmark.
The too much comparative example of Cu content is No.23, otherwise the very few comparative example of content is No.5.Superfluous its toughness of No.23 of its content descends greatly, and the pendulum impact value departs from the qualification determination benchmark.In addition, cutting tool life-span, maximum heat are handled the scope that deflection also departs from the qualification determination benchmark.On the other hand, the very few comparative example of content is the pendulum impact value of No.5, the scope that maximum heat processing deflection also departs from the qualification determination benchmark.
The too much comparative example of Ni content is No.23, otherwise the very few comparative example of content is No.1.The pendulum impact value of the No.23 that its content is superfluous, maximum heat are handled the scope that deflection departs from the qualification determination benchmark.In addition, the cutting tool life-span is also departed from the scope of qualification determination benchmark.
The too small comparative example of being obtained by Mo+0.5W of numerical value is No.24, and its numerical value is No.25 but be equivalent to 3.0% promptly maximum example of cut off value within the scope of the invention.The highest hardness of No.24 and pendulum impact value depart from the qualification determination benchmark.In addition, there is the influence that departs from other prerequisite in No.25, and the pendulum impact value descends.
The too much comparative example of V content is No.26.The No.26 of this comparative example is because the content of V is superfluous, so toughness descends, the pendulum impact value departs from the qualification determination benchmark.In addition, cutting finished surface roughness also departs from the qualification determination benchmark.
The long-pending too much comparative example of C content and Cr content is No.1 and No.2.No.1 and No.2 obviously shorten because of this influence has caused the life-span of cutting tool, and the distortion after the thermal treatment simultaneously increases.
The too much comparative example of N content is No.27.Consequently, toughness descends, and the pendulum impact value departs from the qualification determination benchmark.
The excessive comparative example of parameter that is formed by the ferritic generting element is No.1~4 and No.25.This influence causes the surface accuracy that the flexible balance of these comparative examples is broken or cut is accomplished to worsen.Especially only its toughness of No.25 that departs from this prerequisite descends greatly, and the pendulum impact value departs from the qualification determination benchmark.
The excessive comparative example of parameter that is formed by the austenite generting element is No.2~5, No.12,13,22,23.This influence causes that the retained austenite of these comparative examples increases, the heat treatment deformation amount increases, and shorten the life tools when cutting simultaneously.Especially, No.12 and No.13 the cutting tool life-span and the maximum heat that only depart from this prerequisite are handled deflection and are departed from the qualification determination benchmark.
Describe the present invention with reference to detailed description and specific embodiment, but do not break away from aim of the present invention and scope, can apply various changes and modification, this is readily understood that for a person skilled in the art.
The application is that its content is taken passages at this as a reference based on the application of the Japanese patent application of application on January 10th, 2008 (the special 2008-003524 of hope).
Utilize possibility on the industry
Cold-work die steel of the present invention is used for cold stamping uses mould; Not only possesses these the fundamental characteristics of seeking of hardness, toughness, heat treatment deformation; And can handle by corresponding various hard films; In addition, can also obtain cutting finished surface roughness and cutting tool aspect the life-span cold stamping also out of question use mould.In addition, utilize cold punching die that this cold-work die steel obtains shaping usefulness as the high speed steel plate more than the tensile strength 590MPa, especially can advantageous applications.
Claims (9)
1. a cold-work die steel is characterized in that, contains
C:0.5~0.7 quality %;
Cr:5.0~7.0 quality %;
Si:0.5~2.0 quality %;
Mn:0.1~2.0 quality %;
Al:0.001~0.010 quality %;
Cu:0.25~1.00 quality %;
Ni:0.25~1.00 quality %;
N:0.003~0.025 quality %;
P: greater than 0 and below 0.05 quality %;
S: greater than 0 and below 0.1 quality %;
O: greater than 0 and below 0.005 quality %; And
At least a among Mo and the W,
Surplus is iron and unavoidable impurities,
And satisfy the prerequisite of 0.5≤[Mo]+0.5 * [W]≤3.0 and [C] * [Cr]≤4,
And parameter F P=[Si]/5+ [Cr]/5+2 * [Mo]+[W]+2 * [V]+10 * [Al] that the ferritic generting element forms satisfies≤5.0 prerequisite,
Parameter A P=[Mn]+3 * ([Cu]+[Ni]) that the austenite generting element forms satisfies≤2.5 prerequisite,
Wherein, [] in the following formula represented the mass percentage content of each element.
2. cold-work die steel as claimed in claim 1 is characterized in that, also contains V: greater than 0 and below 0.5 quality %.
3. cold-work die steel as claimed in claim 1 is characterized in that, also contains to add up to greater than 0 and below 0.5 quality %, be selected from least a element among Ti, Zr, Hf, Ta, the Nb.
4. cold-work die steel as claimed in claim 2 is characterized in that, also contains to add up to greater than 0 and below 0.5 quality %, be selected from least a element among Ti, Zr, Hf, Ta, the Nb.
5. cold-work die steel as claimed in claim 1 is characterized in that, also contains Co: greater than 0 and below 10 quality %.
6. cold-work die steel as claimed in claim 2 is characterized in that, also contains Co: greater than 0 and below 10 quality %.
7. cold-work die steel as claimed in claim 3 is characterized in that, also contains Co: greater than 0 and below 10 quality %.
8. cold-work die steel as claimed in claim 4 is characterized in that, also contains Co: greater than 0 and below 10 quality %.
9. mould is used in a cold stamping, it is characterized in that, through each described cold-work die steel in the claim 1~8 is processed, and implements surface treatment and makes.
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JP003524/2008 | 2008-01-10 | ||
JP2008003524A JP5276330B2 (en) | 2008-01-10 | 2008-01-10 | Cold mold steel and cold press mold |
PCT/JP2009/050097 WO2009088027A1 (en) | 2008-01-10 | 2009-01-07 | Cold-work die steel and dies for cold pressing |
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CN101743335B true CN101743335B (en) | 2012-06-06 |
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JP (1) | JP5276330B2 (en) |
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JP5345415B2 (en) * | 2008-03-05 | 2013-11-20 | 山陽特殊製鋼株式会社 | Steel for cold press dies and press dies excellent in machinability, heat treatment sizing characteristics and impact characteristics |
CN102399958A (en) * | 2010-09-07 | 2012-04-04 | 上海明嘉金属科技有限公司 | Shaping apparatus of precise continuous cold punching mold |
CN103465417A (en) * | 2013-09-09 | 2013-12-25 | 昆山奥德鲁自动化技术有限公司 | Anti-wear method for plastic mould |
CN103882339A (en) * | 2014-02-21 | 2014-06-25 | 芜湖市鸿坤汽车零部件有限公司 | High-carbon steel material and preparation method thereof |
KR20170118904A (en) * | 2015-03-26 | 2017-10-25 | 히타치 긴조쿠 가부시키가이샤 | Sliding component and sliding structure |
CN104889266B (en) * | 2015-06-02 | 2017-04-19 | 烟台裕和汽车零部件有限公司 | Manufacture technology of trimming and punching mold of automotive body thermal forming part |
CN108136482B (en) * | 2015-09-29 | 2019-09-17 | 日立金属株式会社 | Warm and hot forging mold, using the warm and hot forging mold forged article manufacturing method and warm and hot forging mold manufacturing method |
CN107313012B (en) * | 2017-06-12 | 2019-03-01 | 上海汇众汽车车桥***有限公司 | A kind of surface treatment method of cold punching die |
CN107475606A (en) * | 2017-06-30 | 2017-12-15 | 太仓旺美模具有限公司 | A kind of corrosion-resistant cold work die steel |
CN110273112A (en) * | 2018-03-16 | 2019-09-24 | 天津普信模具有限公司 | A kind of high-strength durable automobile die material and preparation method thereof |
CN109371329B (en) * | 2018-12-24 | 2021-02-02 | 黄石华中模具材料研究所 | High-temperature-resistant artificial crystal forming die steel material and preparation method thereof |
JP2020132891A (en) * | 2019-02-12 | 2020-08-31 | 山陽特殊製鋼株式会社 | Mold steel having excellent thermal conductivity |
GB202002451D0 (en) * | 2020-02-21 | 2020-04-08 | Rolls Royce Plc | Article and method of manufacturing the same |
CN113355597A (en) * | 2021-05-24 | 2021-09-07 | 如皋市宏茂重型锻压有限公司 | High-toughness high-wear-resistance cold-work die steel and manufacturing process thereof |
JP2023122766A (en) * | 2022-02-24 | 2023-09-05 | 大同特殊鋼株式会社 | Mold steel and metal mold |
CN115319014B (en) * | 2022-08-10 | 2024-04-02 | 成都成德重型锻造有限公司 | Forging quality control method of ratchet disc for nuclear island |
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JPH0765141B2 (en) * | 1985-09-18 | 1995-07-12 | 日立金属株式会社 | Tool steel for hot working |
JPH10273756A (en) * | 1997-03-31 | 1998-10-13 | Daido Steel Co Ltd | Cold tool made of casting, and its production |
JPH11181549A (en) * | 1997-12-22 | 1999-07-06 | Daido Steel Co Ltd | Cold tool made of casting excellent in weldability and its production |
JP2005194563A (en) * | 2004-01-06 | 2005-07-21 | Sanyo Special Steel Co Ltd | High-precision die steel |
JP2006193790A (en) * | 2005-01-14 | 2006-07-27 | Daido Steel Co Ltd | Cold working tool steel |
JP2006328521A (en) * | 2005-05-30 | 2006-12-07 | Daido Steel Co Ltd | Tool for precision working and tool steel |
JP2007197746A (en) * | 2006-01-25 | 2007-08-09 | Daido Steel Co Ltd | Tool steel |
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2009
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WO2009088027A1 (en) | 2009-07-16 |
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