CN105274444A - Steel for cold working tool - Google Patents
Steel for cold working tool Download PDFInfo
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- CN105274444A CN105274444A CN201510252702.3A CN201510252702A CN105274444A CN 105274444 A CN105274444 A CN 105274444A CN 201510252702 A CN201510252702 A CN 201510252702A CN 105274444 A CN105274444 A CN 105274444A
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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
- C22C38/18—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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/84—Controlled slow cooling
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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
- C21D6/002—Heat treatment of ferrous alloys containing Cr
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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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- 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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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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
- C22C38/02—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
- C22C38/04—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
- C22C—ALLOYS
- 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
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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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
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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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
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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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
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/25—Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
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- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/32—Soft annealing, e.g. spheroidising
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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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/02—Hardening by precipitation
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Abstract
The present invention relates to a steel for cold working tool, containing, on a % by mass basis: C: 0.70% to 0.90%; Si: 0.60% to 0.80%; Mn: 0.30% to 0.50%; P: 0.30% or less; S: 0.030% or less; Cu: 0.01% to 0.25%; Ni: 0.01% to 0.25%; Cr: 6.0% to 7.0%; Mo + 1/2W: 2.50% to 3.00%; V: 0.70% to 0.85%; N: 0.020% or less; O: 0.0100% or less; and Al: 0.100% or less, with the balance being Fe and inevitable impurities, in which 1.66 (Mo + 1/2W) + V < 5.7% is satisfied.
Description
Technical field
The present invention relates to cold work tool steel, and especially, relate to the preferred cold work tool steel of high stretching steel plate that is shaped.
Background technology
Usually, the cold work tool steel represented by SKD11, greater than or equal to 1, carry out at the temperature of 000 DEG C quench treatment (quenchingtreatment), then carry out temper (temperingtreatment) at greater than or equal to the temperature of 450 DEG C after, be generally used for the degree of about HRC60 to HRC63.As the main application of this cold work tool steel, example is for colding pressing with mould and mould for cold forging.Such as, patent documentation 1 discloses the size by improving carbide and distributes and realizes the cold work tool steel of high rigidity and high tenacity.
On the other hand, in recent years, in automobile industry, required the countermeasure of global warming issue, and as the most effective solution, many companies are all absorbed in the lightweight of car body.Known to improving the lightweight of car body, the amount of carbon dioxide of discharging from car can be reduced.For this reason, though by when being used for thinner than the thickness of routine time still can provide be generally used as car body materials conventional steel sheet same intensity material be used as car body or structure unit.This material is called high stretching steel plate.
High stretching steel plate is also called " high tensile steel disc (HighTensileStrengthSteelSheets) ", and represents the steel plate with high tensile.Conventional steel plate has the tensile strength being more than or equal to 270MPa, but the steel plate with the tensile strength of 340MPa to 790MPa is normally defined high stretching steel plate.In addition, the steel plate with the tensile strength being more than or equal to 1,000MPa is called Ultra-Drawing steel plate especially.
Patent documentation 1:JP-A-H02-277745
Summary of the invention
From the light-weighted requirement of car body, cold work tool steel (cold working mould) is applied to the processing of Ultra-Drawing steel plate gradually.For this reason, when by use cold working die forming Ultra-Drawing steel plate, the load of cold working mould has been increased.If cold working mould cannot resist load, the dimensional precision of cold working die deformation therefore deteriorated car body or structure unit.In order to obtain sufficient load resistance (loadresistance), hardness and the impact value of cold working mould must be guaranteed.In order to resource-effectively obtain high rigidity considering simultaneously, effectively in quench treatment by relatively large carbon dissolution in material steel to form sosoloid (solidsolution), then to carry out secondary hardening by temper.
As the method increasing the meltage of carbon in sosoloid, example is the method increasing quenching temperature.But, when increasing quenching temperature, the problem of the crystal grain in alligatoring steel may be there is.The crystal grain of alligatoring causes the impact value of punching block to reduce.Therefore, prevent the carbide of grain coarsening as VC under quenching temperature must be included in, but when excessively increase prevents the amount of the carbide of grain coarsening, impact value also reduce.In addition, when adding the element as Mo and V etc., expect that the hardness owing to secondary hardening is improved.
On the other hand, when paying close attention to the manufacturing process of cold working mould, cold working mould generally at room temperature cuts and precision work is final shape.This Cutting Process is the repetition owing to disrumpent feelings (rupture) of the shearing strain of moulding stock (cold work tool steel) and the abrasion of disrumpent feelings chip (rupturedswarf) and instrument, and temporarily and increase the temperature in the face of tool of moulding stock instantaneously.If be difficult to distortion at this high-temperature bed die, if the hardness that is, under high-temperature increases, machinability reduces.That is, increase the load (increasing tool grinder consumption) of the instrument of cutting dies, therefore increase the cost of cutting tool and the manufacturing time of mould, and reduce the productivity of mould.
Consider that above-mentioned situation completes the present invention, the present invention by be provided in guarantee mould necessary hardness and necessary impact value while can improve mould productive cold work tool steel solve the problems referred to above.
As the result of further investigation, the present inventors find to solve the problem.The concrete grammar of dealing with problems is as follows.
A first aspect of the present invention is cold work tool steel, and it comprises in mass %:
C:0.70% to 0.90%;
Si:0.60% to 0.80%;
Mn:0.30% to 0.50%;
Below P:0.30%;
Below S:0.030%;
Cu:0.01% to 0.25%;
Ni:0.01% to 0.25%;
Cr:6.0% to 7.0%;
Mo+1/2W:2.50% to 3.00%;
V:0.70% to 0.85%;
Below N:0.020%;
Below O:0.0100%; With
Below Al:0.100%,
Surplus is Fe and inevitable impurity,
Wherein meet 1.66 (Mo+1/2W)+V<5.7%.
A second aspect of the present invention is the cold work tool steel according to first aspect, and it comprises following at least one in mass % further:
Nb:0.001% to 0.30%,
Ta:0.001% to 0.30%,
Below Ti:0.20%, and
Zr:0.001% to 0.30%.
A third aspect of the present invention is the cold work tool steel according to first aspect or second aspect, and the retained austenite scale of construction after its quenching is for being less than or equal to 25 volume %.
A fourth aspect of the present invention is the cold work tool steel of any one according to first aspect, second aspect and the third aspect, its greater than or equal to the maximum hardness after the temper at the temperature of 450 DEG C for being more than or equal to 64HRC.
The present invention guarantees the necessary hardness of mould and impact value by adjustment C, Si, Cr, Mo, W and V in pre-determined range.In addition, in the present invention, in order to improve the productivity of mould, optimizing the balance between Mo, W and V, and limiting the relational expression of 1.66 (Mo+1/2W)+V<5.7%.Usually, at room temperature cutting dies, and during cutting by heat in metal cutting temporarily and increase the temperature of mould instantaneously.In this case, when paying close attention to the hardness of mould, hardness at room temperature the highest and along with temperature raise and reduce.As the result of the further investigation of the present inventors, find when by cutting temporarily and when increasing the temperature of mould instantaneously, especially, if when adding each element of Mo, W and V more more substantial than predetermined addition, infringement machinability thus deteriorated stock-removing efficiency.That is, the element addition that they sum up Mo, W and V is one of factor reducing die production.
Incidentally, cold work tool steel disclosed in above-mentioned patent documentation 1 realizes high rigidity and high tenacity by the size and distribution improving carbide, but does not have characteristic of the present invention, and therefore the present invention has diverse technological concept.
As mentioned above, according to cold work tool steel of the present invention, the productivity of mould can be improved while the hardness guaranteeing mould necessity and impact value.
Accompanying drawing explanation
Fig. 1 is for illustrating the figure of the relation between tool grinder consumption (machinability) and the addition of Mo, W and V.
Fig. 2 is the figure of the relation illustrated between the impact value of steel of the present invention and comparative steel and the numerical value of hardness.
Embodiment
Cold work tool steel (hereinafter, being called the cold work tool steel of this embodiment) according to one embodiment of the present invention will be described in detail.The cold work tool steel of this embodiment can be applied to and form high stretching steel plate mould, cold forging drift and punch die, bending die, mould for cold forging, squeeze forging (swaging) mould, rolling screw-threads (threadrolling) mould, drift component, slitter knife (slitterknife), punching press lead frame mould, gauger, drawing formed punch (deepdrawingpunch), crooked formed punch, shear-blade, stainless steel bending die, drawing die (drawingdie), plastic working instrument is as hot head, gear drift, cam part, pressurization punching press mould, progressive punching press mould, throw out conveyer sealing plate, screw member, shotcrete machine swivel plate, IC sealing mould, with the accurate pressurizing mold needing high dimensional accuracy.In addition, the various cold metal dices (dice) that use after can also being used for carrying out the surface treatment as CVD process, PVD process and TD process etc. of the cold work tool steel of this embodiment.Wherein, the Ultra-Drawing steel plate of the tensile strength being more than or equal to 1,000MPa is particularly preferred for having.
The cold work tool ladle of this embodiment is containing following element.Below explain the kind of Addition ofelements, its interpolation scope and limit the reason of its scope.
C:0.70% to 0.90%
C is the bioelement guaranteeing intensity and wear resistant, and by with carbide forming element as Cr, Mo, W, V and Nb bonding forms carbide.In addition, to form sosoloid thus to form martensitic structure, C guarantees that hardness is necessary for by being dissolved to parent phase (matrixphase) when quenching.In order to obtain this effect in cold work tool steel, the lower limit set of C content is 0.70%.In contrast, when C content is excessive, thus carbide forming element and C bonding can reduce impact value to form thick carbide.In addition, hot workability when after the casting forge hot being carried out to ingot can be reduced.For those reasons, the upper limit of C content is set as 0.90%.From above-mentioned viewpoint, the more preferably scope of C content is 0.75% to 0.85%.
Si:0.60% to 0.80%
Si is dissolved to parent phase to form sosoloid, and Si can accelerate the precipitation of other carbide, and can contribute to secondary hardening.In order to obtain these effects, the lower limit set of Si content is 0.60%.In contrast, when excessively adding Si, hardenability can be reduced.For this reason, the upper limit of Si content is set as 0.80%.
Mn:0.30% to 0.50%
Add Mn to improve hardenability and stable austenite.Especially, when hardenability reduces, the change of hardness increases at microscopic scale.In addition, when inevitably comprising S, Mn forms MnS, and can prevent from being reduced by the impact value caused owing to heat treated distortion (distortion) (anisotropic growth encourage).For those reasons, the lower limit set of Mn content is 0.30%.In contrast, when Mn content is excessive, hot workability when after the casting forge hot being carried out to ingot can be reduced.For this reason, the upper limit of Mn content is set as 0.50%.
Below P:0.30%
P is inevitably included in steel.P is easy to be segregated in crystal grain boundary and toughness can be caused to reduce.For this reason, the upper limit of P content is set as 0.3%.
Below S:0.030%
S is inevitably included in steel.Usually, S is added energetically to improve machinability.In the present invention, can form MnS to prevent from being reduced by the impact value caused owing to heat treated distortion (anisotropic growth encourage) by adding S, therefore S content is restricted to and is less than or equal to 0.03%.
Cu:0.01 to 0.25%
Cu is the element of stable austenite.But, when Cu content is excessive, the rheological parameters' change with time that therefore size can occur the retained austenite scale of construction can be increased.In addition, when excessively adding Cu, hot workability when after the casting forge hot being carried out to ingot can be reduced.For those reasons, Cu content is set as 0.01% to 0.25%.
Ni:0.01% to 0.25%
Ni is the element of stable austenite.But, when Ni content is excessive, the rheological parameters' change with time that therefore size can occur the retained austenite scale of construction can be increased.For this reason, Ni content is set as 0.01% to 0.25%.
Cr:6.0% to 7.0%
Cr is the element improving erosion resistance.In order to obtain this effect, the lower limit set of Cr content is 6.0%.When Cr content is excessive, C can be reduced and be dissolved to austenitic structure to form the amount of sosoloid, therefore cannot obtain sufficient hardness.For this reason, the upper limit of Cr content is set as 7.0%.
Mo+1/2W:2.50% to 3.00%
Mo and W forms thin carbide, and for contributing to the important element of secondary hardening.In order to obtain the effect identical with Mo, the W of double amount must be added, therefore in the present invention, restriction Mo content and 1/2 the total amount of W content.In order to obtain the effect of secondary hardening, the lower limit set of the content of Mo+1/2W is 2.50%.In contrast, when the content of Mo and W is excessive, can increase the remaining quantity of carbide during quenching, therefore the upper limit of the content of Mo+1/2W is set as 3.00%.
V:0.70% to 0.85%
V can with C bonding to form carbide.Carbide can contribute to the alligatoring suppressing crystal grain diameter.In order to obtain this effect, the lower limit set of V content is 0.70%.When V content is excessive, the carbonitride of V can be easy to crystallization to reduce impact value.For this reason, the upper limit of V content is set as 0.85%.
Below N:0.020%
N is clearance type element (interstitialtypeelement) and can contributes to the increase of the hardness of martensitic structure.Relative to the carbon being all clearance type element, N has stronger γ stability.But when N content is excessive, the nitrogen in solidificating period steel can concentrate so that exceed the restriction of nitrogen ejection, is therefore easy to hole (void) occurs in ingot.For this reason, the upper limit of N content is set as 0.020%.
Below O:0.0100%
O is the element be inevitably included in molten steel.But when O content is excessive, O with Si and Al bonding to form the thick oxide compound that it becomes inclusion, therefore can reduce toughness.From the viewpoint preventing this phenomenon, the upper limit of O content is set as 0.0100%.
Below Al:0.100%
Al is the element being added to reductor.But when Al content is excessive, Al can with O bonding to form thick oxide compound and it can become the starting point of crackle (crack).For this reason, the upper limit of Al content is set as 0.100%.
1.66 (Mo+1/2W)+V: be less than 5.7%
In order to increase secondary hardening, Mo+1/2W and V must be added.In contrast, when its total content is excessive, even if increased the temperature of mould by cutting resistance during cutting or heat in metal cutting, may can not reduce the hardness of mould, therefore can deteriorated machinability.For this reason, its total content is limited to meet 1.66 (Mo+1/2W)+V<5.7.
Except above-mentioned bioelement, the cold work tool steel of this embodiment optionally comprises one or more that be selected from following element.That is, the cold work tool steel of this embodiment can only usually be made up of following unit in mass %: 0.70≤C≤0.90; 0.60≤Si≤0.80; 0.30≤Mn≤0.50; P≤0.30; S≤0.030; 0.01≤Cu≤0.25; 0.01≤Ni≤0.25; 6.0≤Cr≤7.0; 2.50≤Mo+1/2W≤3.00; 0.70≤V≤0.85; N≤0.020; O≤0.0100; With Al≤0.100, surplus is Fe and inevitable impurity, wherein meets 1.66 (Mo+1/2W)+V<5.7%, but it optionally comprises one or more that be selected from its content element as described below.
Nb:0.001% to 0.30%, Ta:0.00l% to 0.30%, below Ti:0.20%, and Zr:0.001% to 0.30%
Nb, Ta, Ti and Zr are with C and N bonding to form the element of carbonitride, and can contribute to the alligatoring suppressing crystal grain.In contrast, when excessively adding Nb, Ta, Ti and Zr, machinability time precision work (finishing) can be reduced, therefore can reduce the productivity of mould.For those reasons, the content of each element is set in above-mentioned scope.
In addition, in the cold work tool steel of this embodiment, the retained austenite scale of construction preferably after quenching is for being less than or equal to 25 volume %.This is because when the retained austenite scale of construction after quenching increases, the die size that can increase owing to the retained austenite scale of construction to be decomposed after tempering changes, and the time therefore may be needed to carry out precision cutting to mould.In addition, preferred quenching temperature is 1,000 DEG C to 1,100 DEG C.
In addition, in the cold work tool steel of this embodiment, preferably, 64HRC is more than or equal to being more than or equal at the temperature of 450 DEG C maximum hardness after temper.Especially, when the cold work tool steel of this embodiment is used as high stretching steel plate cold working mould, hardness and impact value must be guaranteed by applying secondary hardening.
Embodiment
Hereinafter, the present invention is described in detail with reference to embodiment.
In vacuum induced stove, melting respectively has the steel of chemical constitution (quality %) as shown in Table 1 and Table 2, and is cast into each ingot with 50kg weight.These ingots after casting carry out forge hot and form 60mm
2each bar (rodmaterial).After forge hot, these bars are carried out Spheroidizing Annealing (spheroidizingannealing), wherein this material from 880 DEG C with 7 DEG C/time speed of cooling cool lentamente.Evaluate the experiment with measuring of the hardness measurement test of each gained steel, Charpy impact test (CharpyImpactTest), machinability test and the retained austenite scale of construction.
< hardness measurement test >
Bar after above-mentioned thermal treatment cuts out the cube test sheet that the length of side is 10mm, and processes under heat-treat condition (quenching temperature and tempering temperature) as shown in table 3.The measuring surface of cube test sheet and ground plane (groundingsurface) are ground to #400.Then, the hardness by using RockwellCScale to measure cube test sheet.This hardness shows the maximum hardness carried out at greater than or equal to the temperature of 450 DEG C in temper situation.
< Charpy impact test >
Test film finished by preparation 10R-breach card, and the 2mm breach wherein with the 10R degree of depth is formed in from above-mentioned 60mm
2bar in the square bar of 10mm × 10mm × 55mm that cuts out.10R-breach card is finished test film and carry out quench treatment and temper at temperature as shown in table 3, then at room temperature measures its impact value.The mean value of three test films obtains as impact value.
< machinability test (end mill (EndMill) processing experiment) >
Machinability test is carried out to the following test film cut out from steel after annealing.Test conditions is as follows.
Test film: 55mm × 55mm × 200mm
Cutting tool: the square end mill (φ 10mm) of superhard M20
Cut distance: 10m
Cutting speed: 100m/min
The travelling speed often turned: 0.2mm/rev
Cut width (horizontal direction): 0.5mm
Cut height (vertical direction): 0.5mm
Machining oil: nothing
In evaluation, after machining 10m, end mill is separated with support, and measures the maximum wear loss of the angle part of square end mill.The maximum wear loss of the angle part of square end mill is measured by the actual measurement of the CCD camera using 3 x magnifications.Herein, " the maximum wear loss of the angle part of square end mill " shows from the tip of the angle part of square end mill to the maximum value of the distance at position that can confirm to peel off (peeling) and wear away.
The experiment with measuring > of the < retained austenite scale of construction
Will from 60mm
2bar on the square bar of 10mm × 10mm × 2mm that cuts out under quenching temperature as shown in table 3, maintain 30 minutes, then cool with the average cooling rate of 50 DEG C/min.Next, the measuring surface of square bar (test film) is ground to the #800 as JIS-R6001 definition, and by X-ray diffraction measurement device.Obtained the peak intensity of the peak intensity of ferritic (200) and (211) and austenitic (200), (220) and (311) by x-ray measurement, then by peak intensity than calculating the retained austenite scale of construction (volume %).
In table 1 and table 2, the chemical constitution of steel of the present invention and comparative steel is shown.In table 3, heat-treat condition and the test-results of steel of the present invention and comparative steel is shown.In addition, in Fig. 1, the relation between the tool grinder consumption (machinability) of steel of the present invention and comparative steel and the addition of Mo, W and V is shown.In Fig. 2, the relation between the impact value of steel of the present invention and comparative steel and the numerical value of hardness is shown.
Table 3
Contrast table 1, table 2, table 3, Fig. 1 and Fig. 2, can find the following fact.First, in comparative steel 1 to 6,1.66 (Mo+1/2W)+V is more than or equal to 5.7.For this reason, tool grinder consumption increases, and the productivity of mould reduces.Particularly, with reference to Fig. 1, the point that wherein 1.66 (Mo+1/2W) are more than or equal to 5.7 represents comparative steel 1 to 6.In contrast, the point that wherein 1.66 (Mo+1/2W) are less than 5.7 represents steel 1 to 9 of the present invention and comparative steel 7 to 12.As shown in table 1, when in alloy composite, 1.66 (Mo+1/2W) are more than or equal to 5.7, tool grinder consumption increases, and machinability reduces, and the productivity of mould reduces.
With reference to table 1, table 2, table 3 and Fig. 2, because S and V one or both of exceedes the upper limit of limited field of the present invention, so comparative steel 8 to 12 has low impact value.
With reference to table 1, table 2, table 3 and Fig. 2, because the content of Si, Mo and V is lower than the lower limit of limited field of the present invention and Cr content exceedes the upper limit of limited field of the present invention, so comparative steel 13 cannot realize sufficient hardness.In addition, because C content exceedes the upper limit of limited field of the present invention, so comparative steel 13 has low impact value.
With reference to table 1, table 2 and table 3, because the content of Mo and V is lower than the lower limit of limited field of the present invention and Cr content exceedes the upper limit of limited field of the present invention, so comparative steel 14 cannot realize sufficient hardness.In addition, because C content exceedes the upper limit of limited field of the present invention, so comparative steel 14 has low impact value.Incidentally, the comparative steel 16 in table 3 is carry out in composition and tempering temperature and quenching temperature identical with the comparative steel 14 in table 2 example tested under being different from the condition of the comparative steel 14 in table 3.
With reference to table 1, table 2 and table 3, because the content of C, Mo and V is lower than the lower limit of limited field of the present invention and Cr content exceedes the upper limit of limited field of the present invention, so comparative steel 15 cannot realize sufficient hardness.
In contrast, in any test-results of the experiment with measuring of hardness measurement test, Charpy impact test, machinability test and the retained austenite scale of construction, relative to these comparative steel, steel of the present invention realizes excellent result.From the above results, according to the cold work tool steel of the present embodiment, the productivity of mould can be improved while the necessary hardness guaranteeing mould and necessary impact value.
Although describe the present invention in detail with reference to its specific embodiments, but be apparent that, can make various change and change wherein and be not limited to these embodiments and embodiment.
The Japanese patent application 2014-243681 that the Japanese patent application 2014-218985 and 2014 submitted in the Japanese patent application 2014-125901 that the application submitted to based on June 19th, 2014, on October 28th, 2014 submits 2, on December, its content is by reference to introducing herein.
Claims (5)
1. a cold work tool steel, it comprises, in mass %:
C:0.70% to 0.90%;
Si:0.60% to 0.80%;
Mn:0.30% to 0.50%;
Below P:0.30%;
Below S:0.030%;
Cu:0.01% to 0.25%;
Ni:0.01% to 0.25%;
Cr:6.0% to 7.0%;
Mo+1/2W:2.50% to 3.00%;
V:0.70% to 0.85%;
Below N:0.020%;
Below O:0.0100%; With
Below Al:0.100%,
Surplus is Fe and inevitable impurity,
Wherein meet 1.66 (Mo+1/2W)+V<5.7%.
2. cold work tool steel according to claim 1, it comprises further, following at least one in mass %:
Nb:0.001% to 0.30%,
Ta:0.001% to 0.30%,
Below Ti:0.20%, and
Zr:0.001% to 0.30%.
3. cold work tool steel according to claim 1, the retained austenite scale of construction after its quenching is for being less than or equal to 25 volume %.
4. cold work tool steel according to claim 2, the retained austenite scale of construction after its quenching is for being less than or equal to 25 volume %.
5. the cold work tool steel according to any one of Claims 1-4, its greater than or equal to the maximum hardness after the temper at the temperature of 450 DEG C for being more than or equal to 64HRC.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2014-125901 | 2014-06-19 | ||
| JP2014125901 | 2014-06-19 | ||
| JP2014-218985 | 2014-10-28 | ||
| JP2014218985 | 2014-10-28 | ||
| JP2014-243681 | 2014-12-02 | ||
| JP2014243681A JP6439227B2 (en) | 2014-06-19 | 2014-12-02 | Cold work tool steel |
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| Publication Number | Publication Date |
|---|---|
| CN105274444A true CN105274444A (en) | 2016-01-27 |
| CN105274444B CN105274444B (en) | 2019-03-19 |
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|---|---|---|---|
| CN201510252702.3A Active CN105274444B (en) | 2014-06-19 | 2015-05-18 | Cold work tool steel |
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| EP (1) | EP2957647B1 (en) |
| CN (1) | CN105274444B (en) |
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| CN112011740B (en) * | 2020-08-31 | 2021-11-02 | 天津钢研海德科技有限公司 | High-toughness and high-hardness die steel and preparation method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0681037A (en) * | 1992-08-31 | 1994-03-22 | Sumitomo Metal Ind Ltd | Production of hot rolled strip of dual phase stainless steel |
| CN1696326A (en) * | 2004-05-14 | 2005-11-16 | 大同特殊钢株式会社 | Cold work tool steel |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02277745A (en) | 1989-01-20 | 1990-11-14 | Hitachi Metals Ltd | High hardness and high toughness cold tool steel |
| JPH03134136A (en) * | 1989-10-18 | 1991-06-07 | Hitachi Metals Ltd | High hardness and high toughness cold tool steel |
| JP3134136B2 (en) | 1992-12-25 | 2001-02-13 | 中西金属工業株式会社 | Moving object position detection device |
| JP4239300B2 (en) * | 1999-06-14 | 2009-03-18 | 大同特殊鋼株式会社 | Cold mold steel |
| JP5338188B2 (en) * | 2007-10-31 | 2013-11-13 | 大同特殊鋼株式会社 | Alloy tool steel and manufacturing method thereof |
-
2015
- 2015-05-18 CN CN201510252702.3A patent/CN105274444B/en active Active
- 2015-05-28 TW TW104117149A patent/TWI647318B/en active
- 2015-06-12 EP EP15171821.0A patent/EP2957647B1/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0681037A (en) * | 1992-08-31 | 1994-03-22 | Sumitomo Metal Ind Ltd | Production of hot rolled strip of dual phase stainless steel |
| CN1696326A (en) * | 2004-05-14 | 2005-11-16 | 大同特殊钢株式会社 | Cold work tool steel |
Also Published As
| Publication number | Publication date |
|---|---|
| EP2957647B1 (en) | 2017-02-15 |
| EP2957647A2 (en) | 2015-12-23 |
| TWI647318B (en) | 2019-01-11 |
| TW201604291A (en) | 2016-02-01 |
| EP2957647A3 (en) | 2016-01-13 |
| CN105274444B (en) | 2019-03-19 |
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