CN102994902A - Hot-working tool steel having excellent toughness and high-temperature strength and method for production thereof - Google Patents
Hot-working tool steel having excellent toughness and high-temperature strength and method for production thereof Download PDFInfo
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- C21D1/18—Hardening; Quenching with or without subsequent tempering
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Abstract
Disclosed is a hot-working tool steel having improved toughness and high-temperature strength. Also disclosed is a method for producing the hot-working tool steel. The hot-working tool steel comprises the following components (by mass): C: 0.34-0.40%, Si: 0.3-0.5%, Mn: 0.45-0.75%, Ni: 0-0.5% (exclusive), Cr: 4.9-5.5%, (Mo+1/2W): 2.5-2.9% (provided that Mo and W are contained singly or in combination), and V: 0.5-0.7%, with the remainder being Fe and unavoidable impurities. Preferably, the cross-sectional structure of the hot-working tool steel upon quenching contains a granular structure and an acicular structure, wherein the granular structure (A%) accounts for 45 area% or less, the acicular structure (B%) accounts for 40 area% or less, and the remaining austenite (C%) accounts for 5 to 20 volume%.; Also disclosed is a method for producing a hot-working tool steel, which comprises tempering the above-mentioned hot-working tool steel so that a value X determined by the following relational expression between a tempered hardness (HRC) and the percentages of the tissues becomes 40 or greater. X = - 0.36 HRC - 1.47 A % - 1.67 B % + 6.55 C % + 72.91.
Description
The application is that the PCT international filing date is on September 14th, 2007, national applications number is 2007800340590 (former PCT international application no is PCT/JP2007/067915), and denomination of invention is divided an application for the application of " hot working tool steel of toughness and having excellent high-temperature strength and manufacture method thereof ".
Technical field
The present invention relates to a kind of hot working tool steel with toughness and hot strength of improvement, and for the manufacture of the method for this hot working tool steel, described hot working tool steel is suitable for multiple hot work tools, for example pressing machine former, forging die, transfer mold and extrusion tool.
Background technology
Because hot work tools is contact high temperature workpiece or hard workpiece in the process of using, so it need to have intensity and toughness concurrently, with opposing thermal fatigue and impact.Therefore, in the field of hot work tools, use traditionally alloy tool steel, for example the SKD 61 of JIS steel grade.Recently, because by using hot work tools to shorten the manufacturing time of goods, and for the molded article of processed complex, processing work under higher temperature.In order to process simultaneously a plurality of goods, hot work tools for example moding gets larger.Therefore, even in the inside of large size instrument, the hot strength and the toughness that also require hot work tools further to improve with the material assurance.
For toughness and the hot strength of improving alloy tool steel, proposed to improve when keeping toughness by limiting chemical constitution the method (referring to patent document 1) of hot strength, and the method (referring to patent document 2) of improving hot strength and toughness by the amount of regulation Residual Carbides.
Patent document 1:JP-A-02-179848
Patent document 2:JP-A-2000-328196
Summary of the invention
The problem to be solved in the present invention
In the method in patent document 1, although because missing value concrete open and can not estimate toughness levels, yet, judge from the result of study that the inventor carries out, be not enough to provide simultaneously enough high-caliber toughness and hot strength to the restriction of compositing range.Equally, in the method in patent document 2, the amount that only limits Residual Carbides is inadequate so that toughness and hot strength are controlled at high level, and reason is the later impact of organizing martensite for example or bainite structure that greatly is subject to quenching of toughness and hot strength.
An object of the present invention is to provide a kind of really the have toughness of improvement and hot working tool steel and the manufacture method thereof of hot strength.
The means of dealing with problems
As the conscientious result of research, the inventor's later tissue of finding to quench has applied great impact to toughness and hot strength, and has determined to organize after the quenching of a kind of toughness that is suitable for providing simultaneously excellent and hot strength.The inventor finds to exist a very narrow preferred compositing range, wherein passes through various control of elements can obtain organizing after the suitable quenching, thereby finally obtain the present invention in optimum range.
The invention provides a kind of have excellent toughness and the hot working tool steel of hot strength, described hot working tool steel is comprised of the following component that is calculated in mass percent basically: 0.34 to 0.40% C; 0.3 the Si to 0.5%; 0.45 the Mn to 0.75%; 0 to less than 0.5% Ni; 4.9 the Cr to 5.5%; Total amount is 2.5 to 2.9% Mo and 1/2W, wherein can contain alone or in combination Mo and W; With 0.5 to 0.7% V; Surplus is Fe and inevitable impurity.Can be with hot working tool steel tempering according to the present invention, to have the hardness that is not less than 40HRC.Especially, be not less than 43HRC, particularly be not less than the high rigidity aspect of 45HRC, the toughness of the excellence of providing simultaneously and the effect of hot strength are provided described steel.Described steel preferably has the hardness that is not higher than 49HRC.
For hot working tool steel according to the present invention, preferably, consist of the C of this steel, Si, Mn, Ni, Cr, Mo, one or more in W and the V element satisfy the condition of following narrow compositing range.Needless to say, suitable is that whole elements satisfies described condition.
C:0.35 to 0.39%
Si:0.35 to 0.45%
Mn:0.5 to 0.7%
Ni:0.01 to 0.3%
Cr:50 to 54%
(Mo+1/2W): 2.6 to 2.8%, Mo and W contain alone or in combination.
V:0.55 to 0.65%
The present invention also provides the hot working tool steel with above-mentioned composition, and described hot working tool steel contains massive texture and acicular structure at the later fractography that quenches, and the area percent of wherein said massive texture (A%) is not more than 45%; The area percent of described acicular structure (B%) is not more than 40%; And the percent by volume of residual austenite (C%) is 5 to 20%.
And, the invention provides the method that a kind of manufacturing has the hot working tool steel of excellent toughness and hot strength, wherein with described hot working tool steel tempering, so that the X value of being determined by the following relationship between the percentage ratio of tempered-hardness (HRC) and described tissue is not less than 40.Described tempered-hardness is set at 40 to 49HRC, and preferred 43 to 49HRC, and further preferred 45 to 49HRC.
X=[-0.36 * (HRC)-1.47 * (A%)-1.67 * (B%)+6.55 * (C%)+72.91] the invention effect
According to the present invention, can provide simultaneously with very high level toughness and the hot strength of hot working tool steel.When with described steel tempering so that it has the 40HRC of being not less than, for example be not less than 43HRC, more preferably be not less than 45HRC, and when further preferably being not less than again the hardness of 46HRC, obtained to the full extent this effect.Therefore, the invention provides that a kind of multiple high temperature is used and the effective technology of practical application of the hot working tool steel of environment to being applicable to.
Implement best mode of the present invention
As mentioned above, an importance of the present invention is to limit the content that is controlled in the element in the optimum range.Particularly, described aspect of the present invention is to be controlled in the scope of restriction by the content with element, more appropriately, by being familiar with quenching structure described later, find except conventional manufacture method in the interior quenching cooling rate of wide region for example, also exist even by any quenching method, also can provide simultaneously the narrow compositing range of high-caliber toughness and hot strength.Namely, for fundamental element, in the conventional balance that keeps the C-Cr relation with contents, importantly best control and inter-related other carbide forming element of C-Cr content for example Mo, W and V, and according to the control result to these fundamental elements, control applies Si and the Ni of very big impact on character.Below, the reason of the component restriction that the narrow compositing range by the steel according to the present invention consists of is described.
Carbon (C) is and important element essential for hot working tool steel, its some be solid-solubilized in the matrix to provide intensity, and some form carbide to strengthen wear resistance and ablation resistance.And, the interstitial atom that forms sosoloid at carbon, and with having in the substitutional atom situation that for example Cr adds of high affinity with carbon, anticipate I (interstitial atom)-S (substitutional atom) effect, that is, carbon plays opposing drawing-off (drag resistance) work of solute atoms in order to strengthen the effect of intensity.Yet, if carbon content is not more than 0.34 quality %, can not guarantee for tool component enough hardness and wear resistance.On the other hand, because the excessive adding of carbon causes the reduction of toughness and hot strength, so the upper limit of carbon content is restricted to 0.40 quality %.Carbon content is preferably 0.35 to 0.39%, and more preferably 0.36 to 0.38%.
Silicon (Si) is the reductor in the process for making, and is for the element that strengthens machinability.In order to obtain these effects, should add the silicon that is no less than 0.3 quality %.Yet if add too much, acicular structure described later is flourishing, thereby reduces toughness.And therefore cementite base carbide separating out in bainite structure when a large amount of addings of Si suppress to quench impel indirectly that alloy carbide is separated out, cohesion and alligatoring in drawing process, thereby reduce hot strength.Therefore, Si content is restricted to is not more than 0.5 quality %, preferred 0.35 to 0.45%.
Manganese (Mn) has the hardenability of enhancing and suppresses the effect that ferrite produces to obtain suitable quenching/tempered-hardness.If Mn is present in the tissue with the form of non-metallic inclusion MnS, then it has the very big effect of improving machinability.In order to obtain these effects, add the Mn that is no less than 0.45 quality %.If add too much, then the viscosity of matrix increases, thereby reduces machinability.Therefore, Mn content is restricted to is not more than 0.75 quality %, preferred 0.5 to 0.7%.
Nickel (Ni) is the element that produces for suppressing ferrite.And Ni is for the important interpolation element in following aspect: provide excellent hardenability with C, Cr, Mn, Mo, W etc.; Even in the low situation of the rate of cooling of quenching, also obtain to suppress acicular structure produce an effect described later; Form the tissue that is mainly formed by martensite; And prevent that toughness from descending.In addition, Ni has the effect of the toughness of fundamentally improving matrix.Therefore, for example, be no less than 0.01% Ni preferred the adding.The most important thing is among the present invention, even add Ni, also strictly control the upper limit of Ni.If the Ni too high levels, the viscosity of matrix increases, thereby reduces machinability and reduce hot strength.And massive texture described later is flourishing, thereby reduces toughness.Therefore, Ni content is restricted to is not more than 0.5 quality %.Preferably, Ni content is controlled to be not more than 0.3 quality %.
Chromium (Cr) is to have to strengthen hardenability and by forming carbide reinforced matrix and improving the element of the effect of wear resistance, and be the necessary element of hot working tool steel according to the present invention, this helps to improve resistibility and hot strength to softening in the tempering.In order to obtain these effects, should add the Cr that is no less than 4.9 quality %.Yet because the excessive adding of Cr causes hardenability and hot strength to reduce, so the upper limit of Cr content is 5.5 quality %.Cr content is preferably 5.0 to 5.4%, and more preferably 5.1 to 5.3%.
Can add alone or in combination molybdenum (Mo) and tungsten (W), to strengthen hardenability, provide intensity by separating out fine carbide by means of tempering, and improve softening resistance.Because the nucleidic mass of W is about twice of the nucleidic mass of Mo, therefore content can be defined as Mo+1/2W (certainly, can add any, maybe can add two kinds).In order to obtain above-mentioned effect, should add to be no less than 2.5 quality % (Mo+1/2W).Because its excessive adding causes machinability to reduce and by the flourishing caused toughness drop of acicular structure described later, therefore the content of (Mo+1/2W) is not more than 2.9 quality %.Preferably, (Mo+1/2W) content is 2.6 to 2.8%.
Vanadium (V) forms has the carbide of strengthening matrix and improving the effect of wear resistance.And it strengthens the alligatoring to resistibility softening in the tempering and inhibition crystal grain.It also helps the improvement of toughness.In order to obtain these effects, should add the V that is no less than 0.5 quality %.Because the excessive adding of V causes the reduction of machinability and toughness, so the content of V is not more than 0.7 quality %.Preferably, the content of V is 0.55 to 0.65%.
May be P, S, Co, Cu, Al, Ca, Mg, O, N etc. as the inevitable residual principal element of impurity.In order to make effect of the present invention reach maximum, the content of suitable is these elements is low as far as possible.On the other hand, in order to obtain other effect, for example the improvement of the morphology Control of inclusion and mechanical property or manufacturing efficient can also contain and/or add these a small amount of elements.In the case, can think, if these elements content by mass percentage is P≤0.03%, S≤0.01%, Co≤0.05%, Cu≤0.25%, Al≤0.025%, Ca≤0.01%, Mg≤0.01%, O≤0.01% and N≤0.03%, then these elements do not apply king-sized impact to the fundamental property according to hot working tool steel of the present invention.Therefore, above-mentioned scope allows, and above-mentioned percentage ratio is the preferred upper limit.
Except the importance of above-mentioned composition, the present invention also preferably limits feature from the approach according to tissue.Particularly, by the mechanical property tool influential " organizational factor " of research alloy tool steel, except best compositing range, namely beyond the very close limit of the present invention, also define best tissue.That is, has the hot working tool steel of above-mentioned composition according to the present invention in later massive texture and the acicular structure that in fractography, has separately following area percent that contains of quenching.
Massive texture (A%): be not more than 45 area %
Acicular structure (B%): be not more than 40 area %
Residual austenite (C%): 5 to 20 volume %
At first, such as common definition, " quenching structure " refers to the tissue that obtains, mainly be comprised of martensite and/or bainite by from the cooling of austenitic temperature district.Quenching structure of the present invention is comprised of above-mentioned martensite and/or bainite and a small amount of residual austenite basically, and each part by martensite and/or bainite of above-mentioned massive texture and acicular structure forms.Massive texture defined in quenching structure according to the present invention and acicular structure are from different by those of the definition defined of featherlike bainite (upper bainite) and acicular bainite (lower bainite), and this definition is used for the general category of bainite.
That is, massive texture according to the present invention is the several directions of many fine carbides in the tissue tissue of growing wherein.In the fractography of steel, as its name suggests, massive texture according to the present invention presents " block shape " generally.Because even at about 10mm
3Small sample up to also producing massive texture under the rate of cooling of air cooling speed, therefore when the steel ingot with reality quenches, more be difficult to reduce massive texture.Yet, if massive texture accounts for the major part of tissue, toughness drop.Therefore, in the present invention, the area percent of the massive texture in the quenching structure is defined as preferably is not more than 45%, further preferably be not more than 40%, and further preferably be not more than 30% again.
Secondly, acicular structure of the present invention is the tissue of wherein growing in one direction at the many carbide longer than the carbide in the massive texture of organization internal.In fractography, acicular structure according to the present invention presents " shape of pin ".Although this acicular structure generates, when the steel ingot with reality quenches, still be difficult to reduce acicular structure under than the lower rate of cooling of the rate of cooling that begins to generate massive texture.Yet if acicular structure accounts for the major part of tissue, toughness is greatly deteriorated.Therefore, in the present invention, the area percent of the acicular structure in the quenching structure is defined as preferably is not more than 40%, further preferably be not more than 25%.
Observe its section by the difference vision of utilizing shape, can distinguish and quantitatively definite massive texture of the present invention and acicular structure.Particularly, organize in the section any, the two kind tissues poorer than the martensitic matrix that does not wherein have carbide precipitate are preferentially corroded by for example potentiostatic deposition dissolving selectivity etch method (SPEED method) to have erosion resistance.Fig. 1 is the Photomicrograph that obtains by the surface of using scanning electronic microscope (magnification 5000) observation to be corroded.As shown in Fig. 2 and 3 of synoptic diagram as a supplement, can distinguish and quantitatively determine massive texture of the present invention and acicular structure.In the case, in the present invention, observe and wherein organize any 3 visual fields that have separately the above maximum length of about 0.5 μ m to determine that effect is enough.Fig. 1 shows that subsequently in a visual field of the embodiments of the invention steel 6 described in the embodiment 3 it has the massive texture of 27 area % and the acicular structure of 30 area %.Fig. 4 shows that subsequently at a visual field figure of the conventional steel 31 described in the embodiment 3 it has the massive texture of 44 area % and the acicular structure of 16 area %.
And in quenching structure of the present invention consisted of, residual austenite was important.Residual austenite is the tissue that preferably is reduced, and reason is that it makes strength property deteriorated.Yet in the present invention, the residual austenite of appropriate amount helps to improve toughness.Therefore, in the present invention, the percent by volume of the residual austenite in the quenching structure is preferably 5 to 20%, further preferably is not less than 10%.By usual way, for example, measure by utilizing by the percent by volume of the diffracted intensity that uses the X-ray diffraction method of electrolytic polishing sample for example to obtain, can carry out the quantitative analysis of residual austenite.
In the method for the manufacture of hot working tool steel according to the present invention, satisfy the above-mentioned requirements for composition and quenching structure, then then the target hardness in the tempering of definite next step processing carry out tempering, so that the X in the following relationship is not less than 40.Thereby, make the hot working tool steel with excellent toughness.
X=[-0.36 * (HRC)-1.47 * (A%)-1.67 * (B%)+6.55 * (C%)+72.91] wherein
A%: the area percent of massive texture
B%: the area percent of acicular structure
C%: the percent by volume of residual austenite
As on quenching structure and the tempered-hardness result of study on the impact of the toughness after the tempering, above relational expression has been illustrated the concrete parameter that affects.For the toughness that guarantees that tempering is later, the minimizing of massive texture and acicular structure is effective.In these two kinds of tissues, the minimizing of acicular structure that has larger negative coefficient in expression formula is effective especially.On the other hand, found that the residual austenite of appropriate amount advantageously plays a part to guarantee toughness, reason is that residual austenite has large positive coefficient in expression formula.Target hardness can be set in more than the 40HRC that for example realizes hot working tool steel.Yet even target hardness is higher, for example 43HRC is above or more than the 45HRC, the hot working tool steel of the requirement that satisfied composition of the present invention and quenching structure consist of also guarantees enough toughness.Yet, preferably tempered-hardness is remained and is not more than 49HRC, to keep significant toughness.
Embodiment 1
Table 1 has provided the chemical constitution of steel of the present invention, comparative steel and conventional steel.Described comparative steel has the chemical constitution of the narrow compositing range that departs from the present invention's restriction.Described conventional steel is present normally used hot working tool steel, naturally has the chemical constitution beyond compositing range of the present invention.
For steel of the present invention, comparative steel and conventional steel, following manufacturing thickness is that 30mm and width are the steel of 60mm.By in vacuum induction furnace with the 10kg melting, then homogenized 5 hours and make steel ingot 1250 ℃ thermal treatment.Then with them 1150 ℃ of forge hots.After 860 ℃ of annealing, with them from 1030 ℃ of quenchings.Described quenching is undertaken by cooling off in gas under pressure.Here, steel is defined as " half cooling time " from medium temperature (525 ℃) the required time that quenching temperature (1030 ℃) is cooled between described quenching temperature and the room temperature (20 ℃).For example, when being cooled to 525 ℃ of needs in the time of 10 minutes from 1030 ℃, " half cooling " is expressed as 10 minutes.With the form cooling of some steel with " fast cooling ", half cooling time is about 3 minutes, and the part that the wherein rate of cooling of some steel is low, for example centre portions of heavy-gauge steel cooling, half cooling time is about 40 minutes.Subsequently, with steel tempering under different temperature, thereby make it have the hardness of 46HRC.
Make but shellfish (charpy) impact test piece of 2-mm U-breach by each of steel of the present invention, comparative steel and the conventional steel made as mentioned above in the table 1, so that the width of vertically getting forged steel of test specimen, and the breach direction of test specimen is got vertical (that is, it is cut in the T direction) of steel.By using this 2-mm U-breach charpy impact test specimen, at room temperature carry out Charpy impact test.Test-results provides in table 2.Cutting in the situation of shellfish shock test with the test specimen of higher hardness with 46HRC by using in the incision of T direction and tempering, impact value is forged easily the impact of tissue and is reduced.Therefore, if obtain surpassing 34 (J/cm
2) impact value, then described steel has excellent toughness.Particularly, if obtain surpassing 40 (J/cm
2) impact value, then the toughness of steel is very excellent.
[table 2]
Shown by the result who provides in the table 2, if quench by quick cooling, what for to the comparative steel and the conventional steel that form beyond compositing range of the present invention, even by using the test specimen of cutting in the T direction, also can provide relatively high impact value.Yet in the situation that the low rate of cooling that is about 40min with half cooling time is quenched, for having the comparative steel 21 that low Mo content and adding have Ni and the comparative steel 22 with low Mo content, hardenability is poor, and impact value is low.And for the comparative steel 24 to 27 with low Si content, impact value is low.
For wherein except low Mo content, also have carbon content lower slightly and do not add the conventional steel 31 of Ni, hardenability is on duty mutually, and impact value is minimum.For the low conventional steel 32 of wherein Mo content height and impact value trend, machinability is because low-down Si content and deficiency.
On the contrary, for the steel of the present invention 1 to 13 of wherein controlling best chemical constitution, even with low rate of cooling described steel is quenched, also keep excellent toughness.Greatly depart from the comparative steel that forms 23 that the best of the present invention forms for the content that only has wherein by as the Ni of the element that is used for strengthening toughness, even rate of cooling is low, toughness is excellence also.
Embodiment 2
Then, the steel of the present invention that in table 1, provides and relatively hot strength is provided in comparative steel between the comparative steel 23 of high impact value.Obtain test specimen so that test specimen vertically and vertical aligning the (that is, cutting test specimen in the L direction) of forged steel, and by by the resulting tensile strength valence of the tension test of under 650 ℃ high temperature, carrying out.Described tension test with test specimen 650 ℃ the heating and keep beginning later in 10 minutes.Test-results provides in table 3.
[table 3]
The comparative steel 23 that discovery has a composition beyond best composition the of the present invention provide excellent toughness, but low hot strength, reason is that it contains too high Ni content.On the other hand, find that whole steel capital of the present invention has high hot strength.
Embodiment 3
For the steel of the present invention 6 of making among the embodiment 1, comparative steel 21 to 23 and 26 and conventional steel 31 and 32 in be about the steel that 40 minutes low rate of cooling is quenched with half cooling time, as described below, observe their tissue before with their tempering.At first, obtain 10mm for tissues observed from each of these steel
2Sample, and corrode by the SPEED method, with by scanning electronic microscope (* 5000) tissues observed.As an example, in Fig. 1 and 4, shown respectively the image that obtains from steel 6 of the present invention and conventional steel 31.By using this image, measure the area percent of massive texture and acicular structure via image analysis.Similarly, as an example, the steel of the present invention 6 of measurement and the massive texture of conventional steel 31 are shown in the synoptic diagram of Fig. 2 and 5, and the steel of the present invention 6 of measurement and the acicular structure of conventional steel 31 are shown in the synoptic diagram of Fig. 3 (except " * " mark) and 6.Each tissue for each sample is measured 3 visual fields of view, and tries to achieve mean value as area percent.And, above-mentioned sample is polished again, then by electropolishing precision work, to measure the amount of residual austenite by the X-ray diffraction method.The unified result who has provided above measurement in table 4.
[table 4]
In table 5, provided the result of Charpy impact test, and the tempered-hardness of test specimen and the X value that obtained by the relational expression between the percentage ratio of hardness of the present invention and tissue, in embodiment 1, also provided the result of Charpy impact test simultaneously.
[table 5]
※X＝[-0.36＊(HRC)-1.47＊(A％)-1.67＊(B％)+6.55＊(C％)+72.91]
Shown by these results, in the situation of steel being quenched with the rate of cooling that is low to moderate about 40 minutes half cooling time, have separately the comparative steel 21 of low impact value and the quenching structure of conventional steel 31 and have a large amount of massive textures and the residual austenite of less volume, and the acicular structure that toughness is applied very big negative impact is flourishing, in addition, the X value is quite little.For the conventional steel 32 that also has low impact value, its quenching structure is near those tissues of comparative steel 21 and conventional steel 31, and toughness trends towards owing to the balance of various tissues is improved (that is, the X value increases) simultaneously.
Because comparative steel 22 and comparative steel 26 have low Mo content, still too high Ni content, so massive texture is flourishing, thereby impact value is low.For these two kinds of samples, comparative steel 26 has shown the tendency that generates acicular structure, and reason is that in addition it is high also having its Si content.
On the contrary, the quenching structure with steel of the present invention 6 of optimally-controlled chemical constitution has flourishing acicular structure, less massive texture, and in a large number improve toughness aspect effective residual austenite.The balance (that is, X value) of tissue is also excellent.The quenching structure that has a comparative steel 23 of high toughness owing to high Ni content satisfies the X value and is not less than 40 condition, but it has a large amount of massive textures.Yet as mentioned above, comparative steel 23 has low hot strength.
Industrial usability
Has the toughness of improvement and the hot working tool steel of hot strength not only goes for multiple hot work tools according to of the present invention, for example pressing machine former, forging die, transfer mold and extrusion tool, and be applicable to the hot work tools member, for example it is used the mould of high loading.
The accompanying drawing summary
Fig. 1 is that demonstration is according to the section Photomicrograph of an example of the quenching structure of hot working tool steel of the present invention;
Fig. 2 is the synoptic diagram of selecting massive texture from the quenching structure shown in Fig. 1;
Fig. 3 is the synoptic diagram of selecting acicular structure from the quenching structure shown in Fig. 1;
Fig. 4 is the section Photomicrograph of an example of quenching structure that shows the hot working tool steel of comparative example;
Fig. 5 is the synoptic diagram of selecting massive texture from the quenching structure shown in Fig. 4; With
Fig. 6 is the synoptic diagram of selecting acicular structure from the quenching structure shown in Fig. 4.
Claims (17)
1. one kind has excellent toughness and the hot working tool steel of hot strength, and described hot working tool steel is comprised of the following component that is calculated in mass percent basically:
0.34 the C to 0.40%;
0.3 the Si to 0.5%;
0.45 the Mn to 0.75%;
0 to less than 0.5% Ni;
4.9 the Cr to 5.5%;
Total amount is 2.5 to 2.9% Mo and 1/2W, and Mo and W contain alone or in combination;
0.5 the V to 0.7%; And
Surplus is Fe and inevitable impurity.
2. hot working tool steel according to claim 1, described hot working tool steel contains 0.35 to 0.39% C by mass percentage.
3. hot working tool steel according to claim 1, described hot working tool steel contains 0.35 to 0.45% Si by mass percentage.
4. hot working tool steel according to claim 1, described hot working tool steel contains 0.5 to 0.7% Mn by mass percentage.
5. hot working tool steel according to claim 1, described hot working tool steel contains 0.01 to 0.3% Ni by mass percentage.
6. hot working tool steel according to claim 1, described hot working tool steel contains 5.0 to 5.4% Cr by mass percentage.
7. it is 2.6 to 2.8% Mo and 1/2W that hot working tool steel according to claim 1, described hot working tool steel contain total amount by mass percentage, and Mo and W contain alone or in combination.
8. hot working tool steel according to claim 1, described hot working tool steel contains 0.55 to 0.65% V by mass percentage.
9. hot working tool steel according to claim 1, described hot working tool steel has the hardness that is not less than 40HRC.
10. hot working tool steel according to claim 1, described hot working tool steel has the hardness that is not less than 43HRC.
11. hot working tool steel according to claim 1, described hot working tool steel has the hardness that is not less than 45HRC.
12. each described hot working tool steel in 11 according to claim 9, described hot working tool steel has the hardness that is not higher than 49HRC.
13. hot working tool steel according to claim 1, wherein said steel has the fractography that comprises massive texture and acicular structure after quenching, the area percent of described massive texture (A%) is not more than 45%, the area percent of described acicular structure (B%) is not more than 40%, and the percent by volume of residual austenite (C%) is 5 to 20%.
14. a manufacturing has the method for the hot working tool steel of excellent toughness and hot strength, wherein with steel tempering according to claim 13, so that the X value of being determined by the following relationship between the percentage ratio of tempered-hardness (HRC) and described tissue is not less than 40:
X＝[-0.36×(HRC)-1.47×(A％)-1.67×(B％)+6.55×(C％)+72.91]。
15. method according to claim 14 wherein is tempered to 40 to 49HRC with described steel.
16. method according to claim 14 wherein is tempered to 43 to 49HRC with described steel.
17. method according to claim 14 wherein is tempered to 45 to 49HRC with described steel.
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| JP2006-251003 | 2006-09-15 | ||
| JP2006251003 | 2006-09-15 |
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| CNA2007800340590A Division CN101517114A (en) | 2006-09-15 | 2007-09-14 | Hot-working tool steel having excellent stiffness and high-temperature strength and method for production thereof |
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| Country | Link |
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| US (1) | US20100193089A1 (en) |
| EP (1) | EP2065483A4 (en) |
| KR (3) | KR20120006091A (en) |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104271775A (en) * | 2012-05-07 | 2015-01-07 | 沃斯贝茨公司 | Tough bainitic heat treatments on steels for tooling |
| CN114000059A (en) * | 2018-10-05 | 2022-02-01 | 日立金属株式会社 | Hot-work tool steel and hot-work tool |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT506790B1 (en) * | 2008-11-20 | 2009-12-15 | Boehler Edelstahl Gmbh & Co Kg | HOT STEEL ALLOY |
| JP5515442B2 (en) * | 2009-06-16 | 2014-06-11 | 大同特殊鋼株式会社 | Hot tool steel and steel products using the same |
| EP2682491B1 (en) * | 2011-03-03 | 2018-07-04 | Hitachi Metals, Ltd. | Hot work tool steel having excellent toughness, and process of producing same |
| EP2994547A1 (en) * | 2013-03-01 | 2016-03-16 | Rovalma, S.A. | High thermal diffusivity, high toughness and low crack risk during heat treatment tool steel |
| CN105960475B (en) * | 2014-05-28 | 2018-03-30 | 日立金属株式会社 | Hot working has the manufacture method of material and hot working tool |
| CN106574335B (en) | 2014-07-23 | 2019-06-18 | 日立金属株式会社 | Hot working has material, the manufacturing method of hot working tool and hot working tool |
| WO2018182480A1 (en) * | 2017-03-29 | 2018-10-04 | Uddeholms Ab | Hot work tool steel |
| US11535917B2 (en) | 2019-12-03 | 2022-12-27 | Daido Steel Co., Ltd. | Steel for mold, and mold |
| CN113604730A (en) * | 2021-07-05 | 2021-11-05 | 昆山东大特钢制品有限公司 | High-temperature-resistant and high-toughness hot-work die steel and production process thereof |
| CN114535944B (en) * | 2021-12-15 | 2022-11-29 | 河北工业职业技术学院 | Short-process bainite hot working die and preparation method thereof |
| KR20240029270A (en) | 2022-08-26 | 2024-03-05 | 현대자동차주식회사 | Hot-working tool steel and method for manufacturing thereof |
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| JPH02179848A (en) * | 1988-12-30 | 1990-07-12 | Aichi Steel Works Ltd | Hot tool steel |
| JPH08188852A (en) * | 1995-01-04 | 1996-07-23 | Kobe Steel Ltd | Forging die and its production |
| CN1445379A (en) * | 2002-03-15 | 2003-10-01 | 大同特殊钢株式会社 | Hot-working tool steel with good machine work performance and preparation method therefor |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS58123861A (en) * | 1982-01-18 | 1983-07-23 | Daido Steel Co Ltd | Hot working tool steel |
| SE511758C2 (en) * | 1998-03-27 | 1999-11-22 | Uddeholm Tooling Ab | Steel material for hot work tools |
| JP2006104519A (en) * | 2004-10-05 | 2006-04-20 | Daido Steel Co Ltd | High toughness hot tool steel and its production method |
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2007
- 2007-09-14 KR KR1020117031362A patent/KR20120006091A/en active Application Filing
- 2007-09-14 CN CN2012103163783A patent/CN102994902A/en active Pending
- 2007-09-14 US US12/440,406 patent/US20100193089A1/en not_active Abandoned
- 2007-09-14 KR KR1020137006463A patent/KR20130036076A/en active Search and Examination
- 2007-09-14 WO PCT/JP2007/067915 patent/WO2008032816A1/en active Application Filing
- 2007-09-14 CN CNA2007800340590A patent/CN101517114A/en active Pending
- 2007-09-14 EP EP07807322.8A patent/EP2065483A4/en not_active Withdrawn
- 2007-09-14 KR KR1020097005031A patent/KR20090043556A/en not_active Application Discontinuation
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02179848A (en) * | 1988-12-30 | 1990-07-12 | Aichi Steel Works Ltd | Hot tool steel |
| JPH08188852A (en) * | 1995-01-04 | 1996-07-23 | Kobe Steel Ltd | Forging die and its production |
| CN1445379A (en) * | 2002-03-15 | 2003-10-01 | 大同特殊钢株式会社 | Hot-working tool steel with good machine work performance and preparation method therefor |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104271775A (en) * | 2012-05-07 | 2015-01-07 | 沃斯贝茨公司 | Tough bainitic heat treatments on steels for tooling |
| CN114000059A (en) * | 2018-10-05 | 2022-02-01 | 日立金属株式会社 | Hot-work tool steel and hot-work tool |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101517114A (en) | 2009-08-26 |
| EP2065483A1 (en) | 2009-06-03 |
| EP2065483A4 (en) | 2016-03-23 |
| KR20090043556A (en) | 2009-05-06 |
| KR20120006091A (en) | 2012-01-17 |
| WO2008032816A1 (en) | 2008-03-20 |
| US20100193089A1 (en) | 2010-08-05 |
| KR20130036076A (en) | 2013-04-09 |
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