CN1974825A - High strength spring steel wire with excellent coiling properties and hydrogen embrittlement resistance - Google Patents
High strength spring steel wire with excellent coiling properties and hydrogen embrittlement resistance Download PDFInfo
- Publication number
- CN1974825A CN1974825A CNA2006101420674A CN200610142067A CN1974825A CN 1974825 A CN1974825 A CN 1974825A CN A2006101420674 A CNA2006101420674 A CN A2006101420674A CN 200610142067 A CN200610142067 A CN 200610142067A CN 1974825 A CN1974825 A CN 1974825A
- Authority
- CN
- China
- Prior art keywords
- steel wire
- retained austenite
- spring
- surpassing
- steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- 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
- C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
-
- 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
-
- 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
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
-
- 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
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
-
- 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
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Articles (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Abstract
Disclosed herein is a high strength spring steel wire with excellent coiling properties and hydrogen embrittlement resistance. The steel wire comprises, by mass, 0.4 to 0.60% of C, 1.7 to 2.5% of Si, 0.1 to 0.4% of Mn, 0.5 to 2.0% of Cr, 0.015% or less of P (exceeding 0%), 0.015% or less of S (exceeding 0%), 0.006% or less of N (exceeding 0%), 0.001 to 0.07% of Al, and the remainder being Fe and unavoidable impurities. The steel wire has a structure wherein prior austenite has an average grain size of 12 mum or less, and retained austenite exists in an amount of 1.0 to 8.0 vol. % with respect to a whole structure of the steel wire. The retained austenite has an average grain size of 300 nm or less and a maximum grain size of 800 nm or less. The steel has a tensile strength of 1,900 MPa or more.
Description
Technical field
The present invention relates to a kind of high strength spring steel wire with excellent coiling and hydrogen embrittlement resistance, more particularly, relating to a kind of is 1 in tensile strength, the spring wire that coiling and hydrogen embrittlement resistance are enhanced in 900MPa or the higher high strength scope.
Background technology
The needs that reduce Motor vehicles weight are followed size and the thickness that reduces vehicle part.In this, the vehicle floor parts need have high strength such as suspension spring etc.Yet, can when improving the atmosphere fatigue property, reduce corrosion fatigue character because hardness of steel increases usually, so atmosphere fatigue property and corrosion fatigue character are difficult to be enhanced with hardness of steel simultaneously.
In order to improve corrosion fatigue character, advised several method in the art, such as the method for improving erosion resistance, catch the method for hydrogen etc.Yet according to these methods, the increase of required degree will increase the add-on of alloying element, thereby increase material cost, reduce workability simultaneously again.
Given this, the someone has proposed to come the method for strongthener character by improving production technique under the situation that does not increase alloying element content.For example, patent documentation 1 discloses, toughness or sagging resistance that quenching in-coiling disc spring production technique cold by improving and tempered condition are improved the steel that is applied to suspension spring can be realized the high strength as the suspension spring of the finished product under the situation that does not reduce above-mentioned other character.
Similarly, the advantage that has of cold-wind spring is that its character can be easy to strengthen by improving production technique.Producing the technology of cold-coiling disc spring and the technology of production heat-coiling disc spring will be described below.With the technology of production heat-coiling disc spring inequality be, the technology of producing cold-coiling disc spring be with spring quench and tempering after the mode of reeling carry out.Therefore, for the technology of production heat-coiling disc spring, so not harsh than the technology of preparation heat-coiling disc spring for the restriction of quenching and tempered condition.
The technology of＜production heat-coiling disc spring 〉
Spring steel → pickling → tractive → heating → thermoelastic spring coiling → quenching → tempering → curing → shot peening processing → japanning → product
The technology of the cold-coiling disc spring of＜production 〉
Spring steel → pickling → tractive → heating → quenching → tempering → cold spring is reeled → is used to and eliminates strained annealing → curing → shot peening processing → japanning → product
Yet, for the technology of producing cold-coiling disc spring, because reeling, spring after quenching and tempering, carries out, this technology is different from the technology of wherein quenching after spring is reeled in order to regulate intensity with tempered production heat-coiling disc spring, what therefore offer the spring winding process is the steel wire with high strength and low workability, thereby steel wire may break in spring winding process process.This phenomenon along with the increase of hardness of steel significantly.Therefore, for will in the production technique of cold-coiling disc spring, quenching and the tempered steel wire, need excellent ductility (coiling).
In order to ensure the ductility of excellence, for example, patent documentation 2 discloses and has a kind ofly made by adding Nb that C content reduces in austenite structure refinement and the matrix, thereby can guarantee suitable coiling and high-intensity method.In addition, patent documentation 3 discloses a kind of add-on by adjusting Ti and N and has made the austenite structure refinement with TiN, thereby can guarantee excellent ductility and high-intensity method.Yet these two kinds of methods all need to add alloying element, and are not enough to guarantee to be evaluated as the workability or the lower production cost of one of the advantage of cold coiling drum spring.
In patent documentation 4, disclose a kind of density and size, thereby under the situation that does not increase the alloying element amount, improved the method for coiling, delayed fracture character and the fatigue property of high strength spring steel wire by refine austenite tissue and adjusting carbide.Yet, owing to, needs to use at short notice and steel wire heating can be arrived the pyritous added technique, so this method is not a kind of method in common in order to satisfy this requirement.
In the production technique of cold coiling drum spring, quench and tempering after, steel wire coil around and till remaining to rolling technology with the rolling shape under the stress always, in this process sometimes delayed fracture may take place.Delayed fracture be a kind of in heat-treatment process hydrogen from around the hydrogen embrittlement phenomenon that diffuses in the steel wire to be caused, and owing to the sensitivity of the hydrogen embrittlement increase along with intensity of steel wire increases, therefore delayed fracture may take place.Therefore, the steel wire that is used for cold coiling drum spring is compared with the steel wire that is used for hot rolling drum spring, must have excellent hydrogen embrittlement resistance.
Technology as the hydrogen embrittlement resistance of attempting enhancing steel spring silk, patent documentation 5 discloses the method that a kind of preparation is used for the steel wire of spring, promptly, so that being joined, V, Mo, T, Nb and Zr make their precipitate in the steel as a kind of like this mode of hydrogen catch position, preparation is used to have good resistance to hydrogen fatigability and 1, the steel wire that is used for spring of 700MPa or higher tensile strength.Yet, in this method,, therefore be difficult to guarantee high strength and sagging resistance owing to need to add a large amount of alloying elements and need under 500 ℃ or higher temperature, carry out tempering in order to form precipitate.
As mentioned above, in order to utilize the advantage of cold coiling drum spring on aspect low-cost and the high-performance, realize the high strength (1,900MPa or higher tensile strength) of the common spring that under severe condition, uses, need have good coiling and hydrogen embrittlement resistance simultaneously such as suspension spring.Yet in correlation technique, for having 1, the 900MPa or the high strength spring steel wire of high tensile more also do not propose to strengthen simultaneously the method for coiling and hydrogen embrittlement resistance.Particularly, still there is not to propose when the advantage of not sacrificing cold coiling drum spring is such as low-cost and broad applicability, can strengthen simultaneously the technology of coiling and hydrogen embrittlement resistance.
Patent documentation 1: the open publication No. S59-96246 of Japanese Patent
Patent documentation 2: the open publication No. H07-26347 of Japanese Patent
Patent documentation 3: the open publication No. H11-29839 of Japanese Patent
Patent documentation 4: the open publication No. 2002-180198 of Japanese Patent
Patent documentation 5: the open publication No. 2001-288539 of Japanese Patent
Summary of the invention
The present invention carries out for addressing the above problem, the purpose of this invention is to provide a kind of high strength spring steel wire, this steel wire has 1,900MPa or higher tensile strength, and have enhanced coiling and hydrogen embrittlement resistance, thereby this steel wire goes for producing the technology of cold coiling drum spring.Herein, much less, steel wire of the present invention also can be applied to produce the technology of hot rolling drum spring.
According to an aspect of the present invention, can finish above-mentioned and other purpose by the high strength spring steel wire with excellent coiling and hydrogen embrittlement resistance is provided, described steel wire comprises in quality %: 0.4～0.60% C, 1.7～2.5% Si, 0.1～0.4% Mn, 0.5～2.0% Cr, 0.015% or lower P (surpassing 0%), 0.015% or lower S (surpassing 0%), 0.006% or lower N (surpassing 0%), 0.001～0.07% Al, and Fe and inevitable impurity, described steel wire has 1,900MPa or higher tensile strength, and in described steel wire tissue, original austenite has 12 μ m or littler median size and retained austenite accounts for 1.0～8.0 volume % in whole steel wire tissue, and described retained austenite has 300nm or littler median size and 800nm or littler maximum particle diameter.
Steel wire can further comprise 1.0% or lower Ni (surpassing 0%) and/or 1.0% or lower Cu (surpassing 0%).Steel wire can further comprise be selected from by 0.1% or lower Ti (surpassing 0%), 0.2% or lower V (surpassing 0%), 0.1% or lower Nb (surpassing 0%) and 1.0% or the group formed of lower Mo (surpassing 0%) at least a.
Be apparent that from foregoing description according to the present invention, described high strength spring steel wire allows the effective rolling operation in cold spring winding process and thermoelastic spring winding process, and has enhanced hydrogen embrittlement resistance and 1,900MPa or higher tensile strength.As a result, can with low cost supply with as trolley part have a high-intensity suspension spring etc., this suspension spring etc. causes delayed fracture etc. hardly.
Description of drawings
From detailed description below in conjunction with accompanying drawing, will more be expressly understood aforesaid and other purpose and feature of the present invention, wherein:
Fig. 1 is the figure of the conventional thermal treatment process of explanation;
Fig. 2 is the SEM Photomicrograph according to SEM/EBSP method representation retained austenite;
Fig. 3 is the side cross-sectional views that is used for the sample of tension test;
Fig. 4 is the side cross-sectional views that is used for the sample of hydrogen embrittlement resistance test;
Fig. 5 describes the figure that concerns between tensile strength and the percentage of total elongation;
Fig. 6 is described in the figure that concerns between the tensile strength and rupture life in the hydrogen embrittlement resistance test.
Embodiment
The preferred embodiments of the invention will be described hereinbelow in detail with reference to the accompanying drawings.
The present inventor has studied the spring wire that is applicable to the technology of producing cold coiling drum spring, and described cold coiling drum spring has high strength and has the enhanced hydrogen embrittlement resistance under the situation that does not add a large amount of alloying elements.As a result, they find that as described below, median size and the amount of retained austenite and the composition and the tissue thereof of particle size adjustment steel wire by according to original austenite can obtain such steel wire, have therefore created the present invention.
Steel wire tissue according to the present invention will be described below.
The median size of＜original austenite: 12 μ m or littler 〉
At first, according to the present invention, original austenite has 12 μ m or littler median size.The median size of refinement original austenite can reduce the stress concentration that takes place on the crystal boundary of original austenite, and improves the toughness-ductility and the hydrogen embrittlement resistance of steel simultaneously.Original austenite preferably has 10 μ m or littler median size, more preferably 8 μ m or littler median size.
The amount of＜retained austenite: with respect to whole 1.0～8.0 volume % that are organized as 〉
Usually, when carbon steel is quenched, in tissue, form a large amount of retained austenites.In this state, if carbon steel carries out tempering in for example about 250 ℃ of temperature, then retained austenite is decomposed as known in the association area.Yet if the content of C and alloying element is increased, the amount of retained austenite increases through quenching, and therefore, is difficult to decompose through tempering.Thereby when retained austenite was present in the steel after tempering in a large number, retained austenite caused distortion-inductive crystal conversion in the rolling technological process, caused spring breakage (referring to the open publication No. 2003-3241 of Japanese Patent).
Yet the present inventor finds that when the amount of controlling retained austenite and shape (size), retained austenite helps to improve tempering toughness-ductility afterwards, has strengthened the hydrogen embrittlement resistance of steel simultaneously effectively.Particularly, because retained austenite is reduced to a certain degree hardness of steel, so steel reduced the susceptibility to hydrogen embrittlement being enhanced ductile simultaneously, strengthened hydrogen embrittlement resistance thus.In addition, because retained austenite plays the effect of effective hydrogen catch position, therefore catch and strengthened hydrogen embrittlement resistance effectively by hydrogen.
These effects are to realize by the predetermined amount of guaranteeing retained austenite.According to the present invention, this tissue has with respect to whole and is organized as 1.0% or the retained austenite of higher volume ratio.When the amount of retained austenite increases, not only improved the hydrogen capture effect, and reduced susceptibility, thereby improved hydrogen embrittlement resistance hydrogen embrittlement.Therefore, the amount of retained austenite preferred 1.2% or higher, more preferably 1.5% or higher.Yet,,, therefore may cause hydrogen embrittlement because retained austenite decomposes the hydrogen that causes being caught by retained austenite and discharged in a large number in the rolling technological process if the amount of retained austenite is too much.Therefore, according to the present invention, as the upper limit with respect to the volume ratio of whole tissue, the amount of retained austenite is 8.0% or lower.Preferably, retained austenite on be limited to 7.5% or lower.
The median size of＜retained austenite: 300nm or littler, the maximum particle diameter of retained austenite: 800nm or littler 〉
Even when guaranteeing the amount of aforesaid retained austenite, if the amount of retained austenite owing to the isochronous distortion of rolling-inductive crystal conversion reduces, then is difficult to keep the toughness-ductility and the hydrogen embrittlement resistance of excellence.In this, the present inventor finds that the grain refining of retained austenite has suppressed distortion-inductive crystal conversion, and is released in the stress raisers after the deformation inductdion, prevents the fracture of delayed crack or rolling thus.
Particularly, according to the present invention, retained austenite is adjusted to has 300nm or littler median size and the maximum particle diameter of 800nm.In the retained austenite median size is under 300nm or the littler situation, because possible distortion-inductive crystal conversion can not cause extremely serious stress concentration in the rolling process, it is possible therefore preventing to rupture.The preferred 280nm of the median size of retained austenite or littler, more preferably 260nm or littler.In addition, a key character of the present invention is the maximum particle diameter of regulating retained austenite.That is, in the present invention, retained austenite is adjusted to has 800nm or littler maximum particle diameter, takes this, and is suppressed in the rolling process of distortion-inductive crystal conversion after quenching and tempering, thereby has avoided delayed crack.The maximum particle diameter of retained austenite is preferably 600nm, more preferably 500nm or littler.
The amount of retained austenite can be passed through X-ray diffraction method, saturation magnetization method, electron backscattered pattern (EBSP) method etc. and measure (referring to Kobe Steel Engineering Reports, the 52nd volume (2002), the 43rd page).In these methods,, therefore recommend this method because the saturation magnetization method provides accurate measurement.
In addition, the size of retained austenite (median size and maximum particle diameter) can be passed through transmission electron microscope (TEM) or scanning electronic microscope (SEM)/EBSP method mensuration.Simultaneously, because TEM needs preset time to observe predetermined scope owing to range of observation is narrow, therefore in the dimensional measurement of retained austenite, recommend the SEM/EBSP method.
Particularly, will (measuring the total area be 10,000 μ m corresponding to the position with the D (diameter)/4 on the vertical surface of sample (bar-shaped) rolling direction (cross section)
2Or the distance between bigger and the measurement point is 0.03 μ m) be defined as target surface, and when the polishing target surface, for electropolishing is carried out in the distortion that prevents retained austenite.Then, by using the FE-SEM that is attached with the EBSP detector on it, make that the enough EBSP detectors of energy be analyzed this zone when observing with SEM with on the sample of electron beam irradiation in the lens barrel that is placed on SEM.Then, the EBSP image that is projected on the screen is taken with the strong photographic camera of synergy (VE-1000-SIT of Dage-MTI Inc.), and be stored in the computer, the crystallographic system of passing through this image and usefulness matrix subsequently is (for retained austenite, FCC (face-centered cubic lattice)) color mapped of FCC phase is determined in the comparison of the pattern that obtains of simulation.Then, after measuring the mapping area area, obtain the diameter of mapping area by the round trial and error method of this mapping area.At last, on the basis of this mensuration, obtain the median size and the maximum particle diameter of retained austenite.
As mentioned above, the present invention particularly organizes vpg connection to have characteristic in adjusting.In order to obtain to organize shape can be easy to control and have required high-intensity spring wire, need composition (mass percent) control of steel is as follows.
<C：0.4～0.60％>
C guarantees the high-intensity element of steel.According to the present invention, steel wire comprises 0.4% or more high-load C.Preferably, C content is 0.42% or higher.Yet if the C too high levels, the amount of retained austenite increases after quenching and tempering, thereby causes the hydrogen embrittlement resistance variation.In addition, because C also plays a part to make the erosion resistance variation,, need to suppress C content therefore in order to improve the corrosion fatigue character of spring product (for example, suspension spring) as the finished product.Therefore, according to the present invention, C content is 0.60% or lower, preferred 0.59% or lower.
<Si：1.7～2.5％>
Si is the element that improves the required sagging resistance of spring.In order to ensure having the sagging resistance required according to the spring of strength level of the present invention, Si content is necessary for 1.7% or higher.Preferably, Si content is 1.8% or higher.Simultaneously, because Si also plays a part to promote decarburization, therefore too high Si content promotes to form Decarburized layer on the steel surface, and this situation need be removed the stripping technology of Decarburized layer, causes the shortcoming of production cost aspect.Therefore, according to the present invention, be limited to 2.5% on the Si, preferred 2.4% or lower.
<Mn：0.1～0.4％>
Mn is the element that plays the deoxidant element effect, simultaneously by with steel in the reaction of unfavorable element S form MnS, eliminate the disadvantageous effect of S thus.In order to make Mn fully show such effect, Mn content is necessary for 0.1% or higher.Preferably, Mn content is 0.12% or higher.Yet too high Mn content forms and separates out band, causes inhomogeneous character or quenching crack.In addition, too high Mn content makes the retained austenite chap in separating out band in the quenching process.Owing to be difficult to decompose thick retained austenite in drawing process, therefore thick retained austenite produces adverse influence to material character.In this, according to the present invention, be limited to 0.4% or lower, preferred 0.38% or lower on the Mn.
<Cr：0.5～2.0％>
Cr is for improving tempering intensity and erosion resistance effective elements afterwards.Particularly, for the suspension spring of needs high level erosion resistance, Cr is an important element.In order to make Cr fully show such effect, Cr content is necessary for 0.5% or higher.Preferably, Cr content is 0.7% or higher.Yet too high Cr content forms and produces poorly soluble rich Cr carbide, and can not fully be dissolved in the steel with the sosoloid form in quenching process, causes guaranteeing desirable strength.Therefore, according to the present invention, be limited to 2.0% or lower, preferred 1.9% or lower on the Cr.
＜P:0.015% or lower (surpassing 0%) 〉
Because P reduced toughness-ductility, therefore low P content suits, and P on be limited to 0.015%.In the present invention, the upper limit of P is preferably 0.01% or lower, and more preferably 0.008% or lower.
＜S:0.015% or lower (surpassing 0%) 〉
Reduce toughness-ductility because S resembles the P, therefore low S content suits, and S on be limited to 0.015%.According to the present invention, the upper limit of S is preferably 0.01% or lower, and more preferably 0.008% or lower.
＜N:0.006% or lower (surpassing 0%) 〉
If N exists with solid solution state in steel, then it can reduce toughness-ductility and hydrogen embrittlement resistance.Herein, if having Al, Ti etc. in the steel, then N and their formation nitride cause the refinement of organizing.In the present invention, N content is 0.006% or lower, to reduce sosoloid N as far as possible.N content is preferably 0.005% or lower, and more preferably 0.004% or lower.
<Al：0.001～0.07％>
Al adds as the decarburization element usually.In addition, Al and N form AlN, thereby eliminate the influence of sosoloid N, help thinning microstructure simultaneously again.In order to make Al fully show such effect, Al content is necessary for 0.001% or higher.Particularly, in order to stablize sosoloid N, Al content is regulated the twice or higher the suiting of the weight percent content that becomes N.Yet,, therefore need be suppressed at the Al content in the spring wire that contains a large amount of Si because Al resembles to work the element that promotes decarburizating the Si.Therefore, in the present invention, Al content is 0.07% or lower, more preferably 0.06% or lower.
Above-described is essential element according to steel wire of the present invention, and other component of steel wire is Fe and unavoidable impurities.As unavoidable impurities, can according to circumstances add other alloying element such as raw material, production unit etc.In addition, by adding element described below, can further improve the character of steel wire effectively.
＜Ni:1.0% or lower (surpassing 0%) 〉
Ni suppresses the effective element that the steel surface decarburization improves erosion resistance simultaneously.In order to make Ni fully show such effect, suitable is that Ni content is 0.2% or higher.Yet, since too high Ni content cause quenching after the amount of retained austenite finally increase, and reduced the toughness-ductility of steel, therefore in the present invention Ni on be limited to 1.0%.Particularly, break or the consideration that reduces cost from thermal distortion, Ni content is preferably 0.7% or lower, and more preferably 0.5% or lower.
＜Cu:1.0% or lower (surpassing 0%) 〉
As above-mentioned Ni, Cu suppresses the effective element that the steel surface decarburization improves erosion resistance simultaneously.In order to make Cu show such effect fully, suitable is that Cu content is 0.2% or higher.Yet the amount of retained austenite finally increased after too high Cu content caused breaking in the hot procedure or quenching, thereby had reduced the toughness-ductility of steel.Therefore, as the upper limit, the content of Cu is 1.0%, is preferably 0.7% or lower, more preferably 0.5% or lower.In addition, if Cu content has surpassed 0.5%, then Ni content may be controlled to the content (that is, Ni (quality %) 〉=Cu (quality %)) more than or equal to Cu, thereby suppresses the red brittleness that Cu causes.
＜Ti:0.1% or lower (surpassing 0%) 〉
Ti and N or S form nitride or sulfide, eliminate the influence of N or S thus.In addition, Ti forms carbonitride, thereby can thinning microstructure.In order to make Ti fully show such effect, suitable is that Ti content is 0.02% or higher, surpasses 3.5 * N content (quality %) simultaneously.Too high Ti content causes the formation of thick TiN, has reduced toughness-ductility.Therefore, in the present invention, be limited to 0.1% on the Ti.Particularly, in view of the consideration that reduces cost, Ti content is preferably 0.07% or lower.
＜V:0.2% or lower (surpassing 0%) 〉
V is used for forming the element of carbonitride or sulfide with N or C, thereby helps thinning microstructure.In order to make V fully show such effect, V content is preferably 0.02% or higher, and more preferably 0.05% or higher.Yet, because too high V content causes the unnecessary increase of quenching character, cause in the operation of rolling, forming cold tissue, therefore need carry out softening process such as the annealing in the aftertreatment, workability is reduced.Therefore, the upper limit of V is preferably 0.2%.From the consideration that reduces cost, it is 0.18% or lower that V content is suppressed.
＜Nb:0.1% or lower (surpassing 0%) 〉
Nb is used for forming the element of carbonitride or sulfide with N or C, thereby helps thinning microstructure.In order to make Nb fully show such effect, Nb content is preferably 0.003% or higher, and more preferably 0.005% or higher.Yet,, thereby reduced the toughness-ductility of steel because too high Nb content causes the formation of thick carbonitride.Therefore, the upper limit of Nb is preferably 0.1%.From the consideration that reduces cost, suitable is, and Nb content is suppressed is 0.07% or lower.
＜Mo:1.0% or lower (surpassing 0%) 〉
Mo is used for forming the element of carbonitride or sulfide with N or C, thereby helps thinning microstructure.In addition, Mo is for guaranteeing that the intensity after the tempering is effective.In order to make Mo fully show such effect, Mo content preferred 0.15% or higher, more preferably 0.3% or higher.Yet too high Mo content causes the formation of thick carbonitride, therefore reduces the toughness-ductility of steel.Therefore, the upper limit of Mo is preferably 1.0% (more preferably 0.7%).From the consideration that reduces cost, suitable is, and Mo content is suppressed is 0.5% or lower.
The present invention does not have the limit production condition.Can produce by this way according to spring wire of the present invention, for example form steel billet, billet rolling is become rod iron, rod iron is pulled into steel wire, steel wire is quenched and tempering (oil tempering) by molten metal.In order to be easy to form the tissue that can improve hydrogen embrittlement resistance and coiling together with intensity simultaneously, suggestion is quenched and tempering according to the method that describes below after tractive.
Now, will quenching and tempered optimum condition be described with reference to figure 1.At first, in order to regulate the tissue of original austenite, make it have 12 μ m or littler median size, preferably heating retention temperature (T1 of Fig. 1) is 1,100 ℃ or lower, and the heating residence time (t1 of Fig. 1) when quenching is 1,500 second or shorter.If T1 surpasses 1,100 ℃, then carbide or the nitride as tumbler pin (fixing pin) inhibition grain growing is removed, and causes the original austenite chap, thereby is difficult to make original austenite to have 12 μ m or lower median size.In addition, if t1 surpasses 1,500 second, then carbide or nitride chap can not suppress the growth of original austenite.For the carbide that makes cementite-Ji fully is dissolved as sosoloid in heat-processed, T1 is preferably 900 ℃ or higher.More preferably, T1 is 920～1, in 050 ℃ the scope.In addition, t1 is preferably 1 second or longer, more preferably in the scope of 2 seconds≤t1≤1,200 second.
After the heating steel wire, cool off, at this moment, rate of cooling has significant effects to the amount and the size of retained austenite.For amount and the size that the retained austenite that satisfies condition of the present invention is provided, controlled chilling speed importantly is especially in the crystal conversion scope.Average rate of cooling (CR1 of Fig. 1) is preferably 10～50 ℃/second 300～50 ℃ of temperature.Increase if the amount of retained austenite less than 10 ℃/second, then takes place CR1, simultaneously the retained austenite chap.In addition, carry out with the CR1 above 50 ℃/second if quench, then the crystal conversion of steel quickens, and can not guarantee the predetermined amount of retained austenite.
The size of retained austenite is subjected to the influence of the median size and the rate of cooling in the quenching process of original austenite.According to the present invention, the even refinement of retained austenite can make it have 12 μ m or lower median size by regulating original austenite, controls CR1 then as mentioned above and realizes.
The control tempered condition also is being important aspect the amount of retained austenite.Because retained austenite decomposes in drawing process, so preferably the short period of time is carried out tempering at low temperatures.In this, because suitable residence time and temperature are definite according to strength level, so they can be determined according to the required intensity of steel wire.
In addition, as being used for above-mentioned heat treated process furnace, heat treated can be carried out with the order short period of time of electric furnace, salt oven and induction heating (IH) stove.Therefore, the IH stove helps the refinement of original austenite most.
Before tractive, can carry out as the softening annealing carried out in this area, mechanical workout, patenting etc.In addition, after spring is reeled, can carry out being used to eliminate strained annealing, dual bullet hardening treatment, low-temperature annealing, cold-curing etc. as what carry out in this area.
The spring wire according to the present invention of Sheng Chaning is 1 in tensile strength as mentioned above, has excellent coiling and hydrogen embrittlement resistance in 900MPa or the higher high strength scope.Therefore, steel wire according to the present invention can be used for producing the spring that uses in the field of for example Motor vehicles, industrial equipments etc.Particularly, steel wire according to the present invention is best suited for the spring of recovery mechanism that can be applicable to machinery, such as the suspension spring that is used for vehicle hanging, valve spring, clutch spring, brake spring and the analogue that is used for vehicle motor.In addition because too high hardness of steel makes it be difficult to carry out rolling technology, so the yield strength of spring wire on be limited to about 2,300MPa.
Embodiment
Hereinafter will describe the present invention in detail with reference to invention and comparing embodiment.Should be noted that the present invention is not limited to these embodiment, and under the situation that does not depart from the scope of the invention, can carry out improvement and the variation of embodiment.
After A33, obtain the rod iron of φ 14mm at the steel A1 that has the listed composition of table 1 from molten metal formation by hot rolling.Then, in order to estimate character, each rod iron all is cut into the length of 200mm, quenches and tempering (mark of the T1 in the table 2 and 3, t1, CR1, T2, t2 and CR2 presentation graphs 1) under table 2 and 3 listed conditions subsequently.Use electric furnace, salt oven or IH stove to quench and tempering.
In these embodiments, the median size of original austenite is regulated by the treatment condition that control is used to quench, simultaneously, and by controlling the amount and the size of the rate of cooling adjusting retained austenite that quenches.In addition, control tempered condition is to satisfy the requirement of retained austenite amount of the present invention and intensity.Even owing to carry out the tempering of short period of time, after the tempering slowly rate of cooling also can cause the decomposition of retained austenite, so the rate of cooling CR2 after the tempering is 30 ℃/second or higher.
Then, use the sample of above-mentioned acquisition to carry out structure observation, tension test and hydrogen embrittlement test.
At first, for tissues observed, after the position of D/4 becomes target surface in each sample of extraction makes corresponding to the steel wire cross section, measure the median size of original austenite.Particularly, after draw samples, will polish under the state of sample in being embedded in resin, and use the etching solution etching of bitter taste acidic group, till showing the original austenite crystal boundary.The grain size number of original austenite is measured according to the method for JISG 0551, and converts it into granularity.
Then, by the saturation magnetization method (referring to R﹠amp; D Kobe Steel Engineering Reports, the 52nd volume, No.3,43 pages, in December, 2002) measure the amount of retained austenite.In addition, the size of retained austenite is measured by above-mentioned SEM/EBSP method.In Fig. 2, illustrate by using the SEM/EBSP method to detect the example that retained austenite obtains the result.As shown in Figure 2, after detecting retained austenite, use image analysis software (ImagePro) to carry out image analysis as mentioned above, to measure the granularity of retained austenite.Particularly, after measuring detected as mentioned above retained austenite area, obtain the diameter of this area by round trial and error method with respect to the survey area of retained austenite.Then, utilize this diameter to obtain the median size and the maximum particle diameter of retained austenite.Adopt the measurement of SEM/EBSP method, the total area that makes measurement is 10,000 μ m
2Or it is bigger.The matrix of spring wire comprises martensite and very small amount of bainite and the ferrite as main tissue.
Use pinblock speed the test sample that cuts steel wire as shown in Figure 3 and form to be carried out tension test as the universal testing machine of 10mm/min.Utilize this test, measure tensile strength and percentage of total elongation index as intensity and coiling (ductility).In an embodiment, when sample has 1,900MPa or higher tensile strength and 10% or during higher percentage of total elongation are rated as and have excellent coiling (ductility).
For the test of hydrogen embrittlement, use and cut the hydrogen embrittlement test sample that steel wire forms as shown in Figure 3, after negative electrode electric charge-4 a pliability test acquisition rupture life, utilize rupture life to estimate hydrogen embrittlement resistance.In an embodiment, when sample has 1, when 900MPa or higher tensile strength and 1,000 second or higher rupture life, be rated as and have excellent hydrogen embrittlement resistance.
The result of these tests is shown in table 2 and 3.
Table 1
| Steel | Form *(quality %) | |||||||||||||
| C | Si | Mn | Cr | P | S | N | Al | Ni | Cu | Ti | V | Nb | Mo | |
| Al | 0.40 | 1.91 | 0.21 | 1.89 | 0.006 | 0.007 | 0.0030 | 0.0320 | 0.21 | 0.02 | - | 0.123 | - | - |
| A2 | 0.42 | 1.72 | 0.33 | 1.88 | 0.010 | 0.012 | 0.0042 | 0.0351 | 0.02 | - | - | - | - | 0.21 |
| A3 | 0.45 | 2.21 | 0.21 | 0.81 | 0.009 | 0.010 | 0.0045 | 0.0288 | 0.54 | 0.31 | 0.054 | 0.072 | - | - |
| A4 | 0.46 | 1.92 | 0.18 | 1.22 | 0.008 | 0.005 | 0.0051 | 0.0333 | 0.21 | 0.22 | 0.051 | - | - | - |
| A5 | 0.46 | 2.41 | 0.32 | 1.89 | 0.007 | 0.008 | 0.0050 | 0.0499 | 0.73 | 0.57 | 0.055 | - | - | - |
| A6 | 0.47 | 2.03 | 0.33 | 1.78 | 0.013 | 0.012 | 0.0045 | 0.0522 | 0.32 | 0.29 | 0.022 | - | 0.011 | - |
| A7 | 0.47 | 1.71 | 0.37 | 1.80 | 0.008 | 0.008 | 0.0033 | 0.0314 | - | - | - | - | - | - |
| A8 | 0.50 | 1.98 | 0.20 | 1.21 | 0.007 | 0.008 | 0.0052 | 0.0344 | 0.20 | - | - | 0.082 | 0.007 | - |
| A9 | 0.52 | 2.01 | 0.22 | 0.62 | 0.005 | 0.003 | 0.0037 | 0.0210 | 0.22 | 0.22 | - | - | 0.072 | - |
| A10 | 0.51 | 2.45 | 0.39 | 1.77 | 0.009 | 0.011 | 0.0048 | 0.0012 | 0.81 | 0.62 | 0.078 | 0.171 | 0.007 | - |
| A11 | 0.51 | 2.30 | 0.37 | 0.80 | 0.014 | 0.013 | 0.0036 | 0.0327 | 0.22 | 0.24 | - | - | 0.022 | 0.22 |
| A12 | 0.54 | 2.02 | 0.22 | 0.99 | 0.008 | 0.007 | 0.0033 | 0.0271 | 0.11 | 0.13 | - | - | - | 0.52 |
| A13 | 0.55 | 2.31 | 0.21 | 1.02 | 0.009 | 0.010 | 0.0035 | 0.0319 | 0.32 | 0.21 | - | - | 0.021 | 0.55 |
| A14 | 0.54 | 1.72 | 0.22 | 1.21 | 0.007 | 0.006 | 0.0041 | 0.0582 | 0.22 | - | 0.081 | 0.082 | - | - |
| A15 | 0.56 | 1.71 | 0.19 | 1.22 | 0.008 | 0.005 | 0.0039 | 0.0652 | 0.21 | 0.20 | 0.024 | - | - | - |
| A16 | 0.55 | 1.84 | 0.20 | 0.74 | 0.012 | 0.011 | 0.0032 | 0.0316 | 0.33 | 0.21 | 0.025 | - | - | 0.30 |
| A17 | 0.57 | 2.40 | 0.34 | 1.05 | 0.010 | 0.008 | 0.0052 | 0.0358 | 0.32 | 0.24 | 0.012 | 0.047 | 0.022 | - |
| A18 | 0.57 | 1.94 | 0.33 | 1.03 | 0.009 | 0.007 | 0.0055 | 0.0364 | 0.33 | 0.25 | 0.025 | - | - | 0.31 |
| A19 | 0.60 | 2.48 | 0.22 | 0.72 | 0.006 | 0.007 | 0.0032 | 0.0341 | 0.20 | 0.27 | 0.052 | - | - | - |
| A20 | 0.33 | 2.48 | 0.49 | 1.21 | 0.010 | 0.012 | 0.0049 | 0.0422 | 0.78 | 0.53 | 0.078 | - | - | - |
| A21 | 0.34 | 2.79 | 0.51 | 1.88 | 0.011 | 0.014 | 0.0038 | 0.0385 | 0.22 | 0.21 | 0.077 | 0.078 | - | - |
| A22 | 0.45 | 2.22 | 0.82 | 1.89 | 0.010 | 0.010 | 0.0043 | 0.0398 | 0.31 | 0.22 | 0.021 | - | - | 0.22 |
| A23 | 0.47 | 1.77 | 0.20 | 1.78 | 0.018 | 0.022 | 0.0051 | 0.0352 | - | - | - | - | - | - |
| A24 | 0.46 | 1.45 | 0.77 | 0.21 | 0.012 | 0.014 | 0.0048 | 0.0318 | - | - | 0.022 | - | 0.026 | - |
| A25 | 0.45 | 1.44 | 0.21 | 0.72 | 0.011 | 0.012 | 0.0045 | 0.0311 | 0.21 | 0.20 | 0.025 | 0.140 | - | - |
| A26 | 0.50 | 1.82 | 0.38 | 0.98 | 0.012 | 0.014 | 0.0088 | 0.0289 | 0.41 | 0.22 | - | 0.071 | - | - |
| A27 | 0.52 | 2.57 | 0.39 | 1.02 | 0.011 | 0.013 | 0.0051 | 0.0327 | 1.10 | 0.30 | 0.051 | 0.055 | - | - |
| A28 | 0.55 | 2.12 | 0.34 | 1.24 | 0.009 | 0.008 | 0.0058 | 0.1020 | 0.24 | 0.22 | 0.110 | 0.122 | - | - |
| A29 | 0.57 | 2.01 | 0.38 | 1.88 | 0.017 | 0.014 | 0.0055 | 0.0348 | 0.21 | 0.18 | 0.079 | - | - | 1.22 |
| A30 | 0.56 | 2.00 | 0.80 | 1.51 | 0.010 | 0.009 | 0.0034 | 0.0316 | 0.72 | 0.54 | 0.051 | 0.221 | - | - |
| A31 | 0.61 | 1.79 | 0.55 | 1.04 | 0.009 | 0.007 | 0.0032 | 0.0302 | 0.57 | 0.21 | 0.048 | - | - | - |
| A32 | 0.67 | 2.10 | 0.32 | 1.23 | 0.012 | 0.013 | 0.0033 | 0.0324 | 0.52 | 0.23 | 0.053 | 0.140 | - | - |
| A33 | 0.68 | 2.51 | 0.29 | 1.87 | 0.008 | 0.009 | 0.0051 | 0.0352 | 0.50 | 0.79 | 0.050 | 0.127 | - | - |
*Surplus is Fe and unavoidable impurities
Table 2
| Numbering | Steel | Quench | Tempering | The granularity of original-γ (μ m) | The amount of residual-γ (volume %) | The median size of residual-γ (nm) | The maximum particle diameter of residual-γ (nm) | TS (MPa) | El (％) | The hydrogen embrittlement life-span (second) | ||||||
| Process furnace | T1 (℃) | T1 (second) | CR1 (℃/second) | Process furnace | T2 (℃) | T2 (second) | CR2 (℃/second) | |||||||||
| 1 | A1 | Electric furnace | 952 | 600 | 32 | Salt oven | 402 | 240 | 54 | 7.9 | 1.8 | 135 | 178 | 1932 | 21 | 1345 |
| 2 | A1 | Electric furnace | 928 | 900 | 31 | Electric furnace | 373 | 3600 | 52 | 8.8 | 1.6 | 136 | 164 | 1915 | 20 | 1117 |
| 3 | A1 | Electric furnace | 955 | 2400 | 37 | Electric furnace | 371 | 3600 | 55 | 15.7 | 1.9 | 178 | 201 | 1933 | 9 | 578 |
| 4 | A2 | Salt oven | 931 | 900 | 35 | Salt oven | 391 | 240 | 53 | 8.6 | 1.4 | 118 | 154 | 1922 | 20 | 1089 |
| 5 | A3 | The IH stove | 1012 | 5 | 31 | The IH stove | 452 | 2 | 54 | 6.4 | 3.1 | 153 | 198 | 2054 | 18 | 1236 |
| 6 | A3 | The IH stove | 1008 | 5 | 29 | Electric furnace | 381 | 3600 | 52 | 6.5 | 2.9 | 148 | 184 | 2061 | 17 | 1355 |
| 7 | A4 | The IH stove | 981 | 10 | 29 | The IH stove | 451 | 2 | 57 | 8.8 | 2.4 | 163 | 225 | 2013 | 17 | 1174 |
| 8 | A5 | Salt oven | 1002 | 600 | 32 | The IH stove | 461 | 2 | 51 | 10.2 | 6.5 | 217 | 470 | 2061 | 16 | 1035 |
| 9 | A6 | Salt oven | 1004 | 600 | 31 | The 1H stove | 458 | 2 | 54 | 8.9 | 4.7 | 206 | 341 | 2035 | 19 | 1175 |
| 10 | A7 | The IH stove | 952 | 10 | 27 | The IH stove | 447 | 2 | 55 | 10.8 | 4.2 | 197 | 278 | 1943 | 16 | 1109 |
| 11 | A7 | The IH stove | 948 | 10 | 79 | The IH stove | 452 | 2 | 52 | 11.1 | 0.6 | 82 | 101 | 1921 | 14 | 875 |
| 12 | A8 | Salt oven | 934 | 600 | 21 | Salt oven | 422 | 240 | 56 | 8.4 | 2.4 | 134 | 186 | 2078 | 15 | 1176 |
| 13 | A9 | Salt oven | 924 | 600 | 22 | Salt oven | 405 | 240 | 53 | 6.2 | 4.5 | 146 | 195 | 2049 | 17 | 1237 |
| 14 | A10 | Electric furnace | 951 | 1200 | 24 | Salt oven | 482 | 240 | 52 | 5.4 | 3.7 | 164 | 182 | 2011 | 17 | 1304 |
| 15 | A10 | Electric furnace | 951 | 1200 | 25 | The IH stove | 522 | 2 | 51 | 5.8 | 6.6 | 195 | 417 | 2156 | 15 | 1124 |
| 16 | A10 | Salt oven | 1022 | 60 | 26 | The IH stove | 476 | 2 | 54 | 4.7 | 7.8 | 206 | 434 | 2207 | 15 | 1195 |
| 17 | A10 | Salt oven | 1075 | 60 | 24 | The IH stove | 474 | 2 | 56 | 8.5 | 7.5 | 241 | 579 | 2215 | 15 | 1084 |
| 18 | A10 | The IH stove | 1120 | 5 | 24 | The IH stove | 480 | 2 | 56 | 11.8 | 7.9 | 288 | 811 | 2137 | 7 | 1017 |
| 19 | A11 | Salt oven | 952 | 600 | 22 | The IH stove | 482 | 2 | 58 | 8.4 | 2.7 | 138 | 172 | 2055 | 16 | 1255 |
| 20 | A12 | Salt oven | 924 | 600 | 14 | Salt oven | 449 | 240 | 54 | 7.8 | 1.9 | 124 | 168 | 2044 | 16 | 1302 |
| 21 | A13 | Salt oven | 921 | 600 | 17 | Salt oven | 450 | 240 | 54 | 5.7 | 3.9 | 145 | 207 | 2106 | 15 | 1254 |
| 22 | A14 | The IH stove | 943 | 5 | 16 | The IH stove | 491 | 2 | 55 | 5.1 | 4.2 | 136 | 182 | 1987 | 18 | 1372 |
Table 3
| Numbering | Steel | Quench | Tempering | The granularity of original-γ (μ m) | The amount of residual-γ (volume %) | The median size of residual-γ (nm) | The maximum particle diameter of residual-γ (nm) | TS (MPa) | EL (％) | The hydrogen embrittlement life-span (second) | ||||||
| Process furnace | T1 (℃) | T1 (second) | CR1 (℃/second) | Process furnace | T2 (℃) | T2 (second) | CR2 (℃/second) | |||||||||
| 23 | A14 | The IH stove | 940 | 5 | 72 | The IH stove | 497 | 2 | 56 | 5.4 | 0.8 | 63 | 99 | 2011 | 16 | 941 |
| 24 | A15 | The IH stove | 941 | 5 | 38 | The IH stove | 484 | 2 | 53 | 8.1 | 3.7 | 147 | 172 | 1944 | 18 | 1169 |
| 25 | A15 | The IH stove | 952 | 5 | 8 | The IH stove | 482 | 2 | 51 | 8.2 | 6.1 | 318 | 602 | 1918 | 8 | 1054 |
| 26 | A16 | The IH stove | 935 | 5 | 39 | The IH stove | 488 | 2 | 52 | 7.8 | 4.8 | 182 | 218 | 1964 | 18 | 1278 |
| 27 | A17 | Salt oven | 927 | 600 | 45 | Salt oven | 432 | 240 | 52 | 7.2 | 2.1 | 165 | 207 | 1998 | 18 | 1214 |
| 28 | A18 | Salt oven | 954 | 600 | 48 | Salt oven | 433 | 240 | 55 | 9.1 | 4.1 | 188 | 243 | 2078 | 16 | 1105 |
| 29 | A19 | Salt oven | 975 | 600 | 47 | The IH stove | 482 | 2 | 54 | 8.8 | 7.4 | 246 | 398 | 2101 | 14 | 1098 |
| 30 | A19 | Salt oven | 978 | 600 | 5 | The IH stove | 461 | 2 | 56 | 9.2 | 9.2 | 313 | 804 | 2240 | 7 | 1023 |
| 31 | A19 | The IH stove | 1102 | 5 | 28 | The IH stove | 497 | 2 | 52 | 24.7 | 7.1 | 255 | 465 | 2096 | 8 | 312 |
| 32 | A20 | Electric furnace | 955 | 900 | 29 | The IH stove | 442 | 3600 | 51 | 9.4 | 0.4 | 40 | 72 | 1823 | 25 | 904 |
| 33 | A21 | Electric furnace | 953 | 900 | 27 | The IH stove | 451 | 3600 | 58 | 6.4 | 0.8 | 33 | 62 | 1854 | 27 | 964 |
| 34 | A22 | Salt oven | 931 | 600 | 25 | The IH stove | 451 | 2 | 57 | 8.4 | 8.8 | 287 | 814 | 2085 | 8 | 713 |
| 35 | A23 | The IH stove | 950 | 10 | 24 | The IH stove | 449 | 2 | 55 | 10.5 | 5.1 | 204 | 321 | 2041 | 7 | 502 |
| 36 | A24 | The IH stove | 948 | 5 | 28 | The 1H stove | 452 | 2 | 54 | 7.9 | 8.4 | 234 | 798 | 1834 | 13 | 1123 |
| 37 | A25 | Salt oven | 934 | 600 | 27 | The IH stove | 452 | 2 | 53 | 8.4 | 4.5 | 164 | 195 | 1866 | 20 | 1324 |
| 38 | A26 | Salt oven | 935 | 600 | 32 | The IH stove | 451 | 2 | 52 | 7.8 | 4.4 | 162 | 185 | 2031 | 8 | 1034 |
| 39 | A27 | Salt oven | 933 | 600 | 34 | The IH stove | 455 | 2 | 54 | 8.2 | 14.1 | 356 | 895 | 2015 | 9 | 824 |
| 40 | A28 | Salt oven | 927 | 600 | 38 | The IH stove | 454 | 2 | 51 | 7.4 | 5.2 | 188 | 236 | 2054 | 9 | 1033 |
| 41 | A29 | Salt oven | 925 | 600 | 37 | The IH stove | 449 | 2 | 52 | 6.5 | 6.1 | 189 | 234 | 2096 | 8 | 632 |
| 42 | A30 | Salt oven | 923 | 600 | 39 | The IH stove | 432 | 2 | 51 | 6.4 | 10.2 | 304 | 811 | 2130 | 8 | 774 |
| 43 | A31 | Salt oven | 934 | 600 | 35 | The IH stove | 440 | 2 | 53 | 12.8 | 8.7 | 245 | 546 | 2034 | 8 | 514 |
| 44 | A32 | Salt oven | 928 | 600 | 8 | The IH stove | 437 | 2 | 54 | 71 | 15.2 | 365 | 862 | 2264 | 6 | 422 |
| 45 | A33 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
To 3, can estimate following (in addition, " numbering " represents " numbering " of table 2 and 3) from table 1.
The numbering 1,2,4～10,12～17,19～22,24 and 26～29 that satisfies requirement of the present invention has 1, the high tensile of 900MPa and excellent percentage of total elongation, thereby in severe rugged environment, show excellent hydrogen embrittlement resistance, good coiling is provided simultaneously.
On the contrary, numbering 3,11,18,23,25 and 30～45 does not satisfy requirement of the present invention, and has following shortcoming.
Be equipped with by satisfying the steel that the present invention forms although number 3,11,18,23,25,30 and 31, they do not quench under optimum condition of the present invention, therefore suffer the increase of original austenite and retained austenite alligatoring and retained austenite amount.As a result, its ductility and hydrogen embrittlement resistance reduce.Particularly, because the 3 heating residence times that are used to quench of numbering are long, so it has the original austenite of chap.For numbering 11 and 23,, therefore can not fully guarantee the amount of retained austenite because the rate of cooling of quenching is too rapid.For numbering 18, owing to effectively help Ti, the V of structure refinement and the too high levels of Nb, so the granularity of original austenite is little, but because the Heating temperature that is used to quench is too high, so the maximum particle diameter of retained austenite has surpassed maximum particle diameter of the present invention.For numbering 25, because the rate of cooling that is used to quench is slow, so the median size of retained austenite surpasses the upper limit that requires according to the present invention.For numbering 30, because the rate of cooling that is used to quench is too slow, so the thick retained austenite of excessive formation.In addition, for numbering 31, because the Heating temperature that is used to quench is too high, so the original austenite grains chap.
Numbering 32～45 does not satisfy composition of the present invention, thereby does not have good properties.For numbering 32 and 33, because they are by the steel A20 with C content lower than C content of the present invention and A21 preparation, so their retained austenites of not having required intensity and not having q.s.For numbering 33, because it is to be prepared by the steel A21 with too high Si content, so it suffers decarburization in the operation of rolling.
For numbering 34,36,42 and 43, because they are by steel A22, A24 with high Mn content, A30 and A31 preparation, so the amount of retained austenite and size increase have surpassed requirement of the present invention.
For numbering 35 and 41, because they are to be prepared by steel A23 with too high P and/or S content and A29, although they satisfy requirement of the present invention on the amount of the median size of original austenite and retained austenite and size, their ductility or hydrogen embrittlement resistance reduce.
For numbering 37, because it is by the insufficient steel A25 preparation of Si content, so it does not have required intensity.
For numbering 38, because it is to be prepared by the steel A26 with too high N content, although it has the tissue that satisfies requirement of the present invention, ductility reduces.
For numbering 39,,, have the amount and the size of the retained austenite that exceeds requirement of the present invention although therefore it does not suffer decarburization because it is to be prepared by the steel A27 with high Si content and too high Ni content.
For numbering 40, because it has excessive Al and Ti, so it suffers decarburization, and ductility reduces.
For numbering 44, because it is by the steel A32 preparation with too high C content, and quench being lower than under undesirable speed of cooling of speed of cooling of the present invention, so the amount of retained austenite and size increase.At last, for numbering 45, because it is by the steel A33 preparation with too high Cu content, so it breaks, thereby can not carry out processing subsequently.
Fig. 5 describes the figure that concerns between routine tensile strength that obtains and the percentage of total elongation by organizing and implementing.As shown in Figure 5, can estimate spring wire of the present invention and in the high strength scope, have excellent coiling.In addition, Fig. 6 be describe by organize and implement that example obtains from the figure that concerns between the tensile strength of hydrogen embrittlement resistance test and the rupture life.As shown in Figure 6, can estimate spring wire of the present invention and in the high strength scope, have excellent hydrogen embrittlement resistance.
Should be appreciated that embodiment and accompanying drawing are to describe for the purpose of illustration, and the present invention is subjected to the appended claim restriction.In addition, it will be apparent to one skilled in the art that under the scope of the invention and the situation of spirit that do not depart from as described in the appended claims, can carry out various improvement, interpolation and substitute.
Claims (4)
1. high strength spring steel wire with excellent coiling and hydrogen embrittlement resistance, it is characterized in that, described steel wire comprises in quality %: 0.4～0.60% C, 1.7～2.5% Si, 0.1～0.4% Mn, 0.5～2.0% Cr, 0.015% or lower P (surpassing 0%), 0.015% or lower S (surpassing 0%), 0.006% or lower N (surpassing 0%), 0.001～0.07% Al, and Fe and unavoidable impurities, described steel wire has 1,900MPa or higher tensile strength, and in described steel wire tissue, original austenite has 12 μ m or littler median size and retained austenite accounts for 1.0～8.0 volume % in whole steel wire tissue, and described retained austenite has 300nm or littler median size and 800nm or littler maximum particle diameter.
2. according to the spring wire of claim 1, it is characterized in that described spring wire also comprises in quality %: 1.0% or lower Ni (surpassing 0%) and/or 1.0% or lower Cu (surpassing 0%).
3. according to the spring wire of claim 1, it is characterized in that described spring wire also comprises in quality %: be selected from by 0.1% or lower Ti (surpassing 0%), 0.2% or lower V (surpassing 0%), 0.1% or lower Nb (surpassing 0%) and 1.0% or the group formed of lower Mo (above 0%) at least a.
4. according to the spring wire of claim 2, it is characterized in that described spring wire also comprises in quality %: be selected from by 0.1% or lower Ti (surpassing 0%), 0.2% or lower V (surpassing 0%), 0.1% or lower Nb (surpassing 0%) and 1.0% or the group formed of lower Mo (above 0%) at least a.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005349113A JP4423254B2 (en) | 2005-12-02 | 2005-12-02 | High strength spring steel wire with excellent coiling and hydrogen embrittlement resistance |
| JP2005349113 | 2005-12-02 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1974825A true CN1974825A (en) | 2007-06-06 |
| CN100455691C CN100455691C (en) | 2009-01-28 |
Family
ID=38117544
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006101420674A Expired - Fee Related CN100455691C (en) | 2005-12-02 | 2006-10-08 | High strength spring steel wire with excellent coiling properties and hydrogen embrittlement resistance |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US20070125456A1 (en) |
| JP (1) | JP4423254B2 (en) |
| KR (1) | KR100839726B1 (en) |
| CN (1) | CN100455691C (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102362001A (en) * | 2009-03-25 | 2012-02-22 | 日本发条株式会社 | High-strength and high-ductility steel for spring, method for producing same, and spring |
| CN103725954A (en) * | 2013-12-16 | 2014-04-16 | 兴化市新光合金材料有限公司 | High-strength corrosion-resistance steel wire and manufacturing process thereof |
| CN104074900A (en) * | 2014-06-29 | 2014-10-01 | 奉化市飞天人精密模具设计有限公司 | Automobile shock absorber and heat treatment process thereof |
| CN104088940A (en) * | 2014-06-29 | 2014-10-08 | 奉化市飞天人精密模具设计有限公司 | Automobile shock absorber cover and heat treatment process thereof |
| CN104334763A (en) * | 2012-06-11 | 2015-02-04 | 株式会社神户制钢所 | Seamless steel pipe for hollow spring |
| CN104428436A (en) * | 2012-07-06 | 2015-03-18 | 株式会社理研 | Valve seat made of iron-base sintered alloy |
| TWI496924B (en) * | 2012-05-31 | 2015-08-21 | Kobe Steel Ltd | Steel wire for high strength spring having excellent coil tension and hydrogen embrittlement resistance and a method for manufacturing the same |
| CN107794441A (en) * | 2016-09-01 | 2018-03-13 | 株式会社Posco | The excellent high-strength spring steel material of hydrogen embrittlement and its manufacture method |
| CN108239726A (en) * | 2016-12-23 | 2018-07-03 | 株式会社Posco | The excellent high-strength spring steel material of resistance to hydrogen embrittlement and its manufacturing method |
| CN112840058A (en) * | 2018-08-21 | 2021-05-25 | 株式会社Posco | Wire rod and steel wire for spring having enhanced toughness and corrosion fatigue properties, and methods for manufacturing same |
Families Citing this family (30)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1674588B1 (en) * | 2004-12-22 | 2010-02-10 | Kabushiki Kaisha Kobe Seiko Sho | High carbon steel wire material having excellent wire drawability and manufacturing process thereof |
| JP4027956B2 (en) * | 2006-01-23 | 2007-12-26 | 株式会社神戸製鋼所 | High strength spring steel having excellent brittle fracture resistance and method for producing the same |
| JP2007327084A (en) * | 2006-06-06 | 2007-12-20 | Kobe Steel Ltd | Wire rod having excellent wire drawability and its production method |
| JP5121360B2 (en) * | 2007-09-10 | 2013-01-16 | 株式会社神戸製鋼所 | Spring steel wire rod excellent in decarburization resistance and wire drawing workability, and method for producing the same |
| JP5600502B2 (en) * | 2010-07-06 | 2014-10-01 | 株式会社神戸製鋼所 | Steel for bolts, bolts and methods for producing bolts |
| JP5683230B2 (en) * | 2010-11-22 | 2015-03-11 | 日本発條株式会社 | Spring and manufacturing method thereof |
| KR20130137137A (en) * | 2010-08-04 | 2013-12-16 | 니혼 하츠쵸 가부시키가이샤 | Spring and manufacture method thereof |
| JP2012214859A (en) * | 2011-04-01 | 2012-11-08 | Nhk Spring Co Ltd | Spring, and method for producing the same |
| MX369258B (en) * | 2011-07-06 | 2019-10-31 | Nippon Steel Corp | Hot-dip plated cold-rolled steel sheet and process for producing same. |
| JP2013036087A (en) * | 2011-08-09 | 2013-02-21 | Nhk Spring Co Ltd | Material for spring and manufacturing method thereof, and spring |
| JP5973903B2 (en) * | 2012-12-21 | 2016-08-23 | 株式会社神戸製鋼所 | High strength spring steel wire excellent in hydrogen embrittlement resistance, method for producing the same, and high strength spring |
| JP6212473B2 (en) * | 2013-12-27 | 2017-10-11 | 株式会社神戸製鋼所 | Rolled material for high-strength spring and high-strength spring wire using the same |
| CN104805365B (en) * | 2014-01-28 | 2017-06-20 | 重庆凌云工具有限公司 | A kind of low alloy high-speed tool steel and a kind of cutter exempt from technique of quenching |
| JP6232324B2 (en) * | 2014-03-24 | 2017-11-15 | Ｊｆｅスチール株式会社 | Stabilizer steel and stabilizer with high strength and excellent corrosion resistance, and method for producing the same |
| WO2015144318A1 (en) * | 2014-03-28 | 2015-10-01 | Tata Steel Ijmuiden B.V. | Method for hot forming a coated steel blank |
| CN104088891A (en) * | 2014-06-29 | 2014-10-08 | 奉化市飞天人精密模具设计有限公司 | Automobile connection rod and thermal treatment process thereof |
| CN105177419A (en) * | 2015-08-14 | 2015-12-23 | 河北钢铁股份有限公司 | Low-yield-strength anti-seismic steel plate for building and production method of steel plate |
| CN105177420A (en) * | 2015-10-08 | 2015-12-23 | 山东钢铁股份有限公司 | S275NL high-tenacity and fine-grain structure steel plate and preparation method thereof |
| CN105177421B (en) * | 2015-10-08 | 2017-06-13 | 山东钢铁股份有限公司 | A kind of yield strength is 500MPa rank forklift truck transverse beam steel plate specials and preparation method thereof |
| CN105256245A (en) * | 2015-10-15 | 2016-01-20 | 中钢集团邢台机械轧辊有限公司 | Cold rolling roller with ultra-deep hardening layer and manufacturing method of cold rolling roller |
| JP6728817B2 (en) * | 2016-03-17 | 2020-07-22 | 日本製鉄株式会社 | High strength spring steel and spring |
| CN106086675A (en) * | 2016-07-22 | 2016-11-09 | 柳州科尔特锻造机械有限公司 | A kind of process of steel alloy |
| CN106086665B (en) * | 2016-08-12 | 2018-08-07 | 武汉钢铁有限公司 | A kind of yield strength 530MPa grades of Hot Rolling Automobile steel plates and production method |
| CN106086686B (en) * | 2016-08-24 | 2018-01-23 | 武汉钢铁有限公司 | With the tensile strength >=2100MPa hot formings steel and production method of medium thin slab Direct Rolling |
| CN106086685B (en) * | 2016-08-24 | 2018-01-12 | 武汉钢铁有限公司 | With the thin hot forming steel of tensile strength >=1500MPa of sheet billet Direct Rolling and production method |
| CN106086684B (en) * | 2016-08-24 | 2018-01-12 | 武汉钢铁有限公司 | With the thin hot forming steel of tensile strength >=1900MPa of sheet billet Direct Rolling and production method |
| JP6356309B1 (en) | 2016-10-19 | 2018-07-11 | 三菱製鋼株式会社 | High-strength spring, method for manufacturing the same, steel for high-strength spring, and method for manufacturing the same |
| KR101867709B1 (en) * | 2016-12-06 | 2018-06-14 | 주식회사 포스코 | Wire rod and steel wire for spring having excellent corrosion fatigue resistance and method for manufacturing the same |
| CN110760748B (en) | 2018-07-27 | 2021-05-14 | 宝山钢铁股份有限公司 | Spring steel with excellent fatigue life and manufacturing method thereof |
| JP7434748B2 (en) * | 2019-08-08 | 2024-02-21 | 大同特殊鋼株式会社 | spring steel |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5240520A (en) * | 1990-11-19 | 1993-08-31 | Nippon Steel Corporation | High strength, ultra fine steel wire having excellent workability in stranding and process and apparatus for producing the same |
| JP2842579B2 (en) * | 1991-10-02 | 1999-01-06 | 株式会社 神戸製鋼所 | High strength spring steel with excellent fatigue strength |
| JP3233188B2 (en) * | 1995-09-01 | 2001-11-26 | 住友電気工業株式会社 | Oil-tempered wire for high toughness spring and method of manufacturing the same |
| US5776267A (en) * | 1995-10-27 | 1998-07-07 | Kabushiki Kaisha Kobe Seiko Sho | Spring steel with excellent resistance to hydrogen embrittlement and fatigue |
| JP3409277B2 (en) * | 1998-05-13 | 2003-05-26 | 株式会社神戸製鋼所 | Rolled steel or bar steel for non-heat treated springs |
| JP3595901B2 (en) * | 1998-10-01 | 2004-12-02 | 鈴木金属工業株式会社 | High strength steel wire for spring and manufacturing method thereof |
| JP3971571B2 (en) * | 2000-12-20 | 2007-09-05 | 新日本製鐵株式会社 | Steel wire for high strength spring |
| US7074282B2 (en) * | 2000-12-20 | 2006-07-11 | Kabushiki Kaisha Kobe Seiko Sho | Steel wire rod for hard drawn spring, drawn wire rod for hard drawn spring and hard drawn spring, and method for producing hard drawn spring |
| CN1305020A (en) * | 2001-02-19 | 2001-07-25 | 北满特殊钢股份有限公司 | High-strength high-toughness spring steel |
| JP2003105485A (en) * | 2001-09-26 | 2003-04-09 | Nippon Steel Corp | High strength spring steel having excellent hydrogen fatigue cracking resistance, and production method therefor |
-
2005
- 2005-12-02 JP JP2005349113A patent/JP4423254B2/en not_active Expired - Fee Related
-
2006
- 2006-08-07 US US11/462,894 patent/US20070125456A1/en not_active Abandoned
- 2006-10-08 CN CNB2006101420674A patent/CN100455691C/en not_active Expired - Fee Related
- 2006-12-01 KR KR1020060120423A patent/KR100839726B1/en active IP Right Grant
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102362001B (en) * | 2009-03-25 | 2013-10-02 | 日本发条株式会社 | High-strength and high-ductility steel for spring, method for producing same, and spring |
| CN102362001A (en) * | 2009-03-25 | 2012-02-22 | 日本发条株式会社 | High-strength and high-ductility steel for spring, method for producing same, and spring |
| TWI496924B (en) * | 2012-05-31 | 2015-08-21 | Kobe Steel Ltd | Steel wire for high strength spring having excellent coil tension and hydrogen embrittlement resistance and a method for manufacturing the same |
| CN104334763B (en) * | 2012-06-11 | 2016-11-23 | 株式会社神户制钢所 | Hollow spring seamless steel pipe |
| US9650704B2 (en) | 2012-06-11 | 2017-05-16 | Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) | Seamless steel pipe for hollow spring |
| CN104334763A (en) * | 2012-06-11 | 2015-02-04 | 株式会社神户制钢所 | Seamless steel pipe for hollow spring |
| CN104428436A (en) * | 2012-07-06 | 2015-03-18 | 株式会社理研 | Valve seat made of iron-base sintered alloy |
| CN104428436B (en) * | 2012-07-06 | 2016-10-26 | 株式会社理研 | Iron-base sintered alloy valve seat |
| CN103725954A (en) * | 2013-12-16 | 2014-04-16 | 兴化市新光合金材料有限公司 | High-strength corrosion-resistance steel wire and manufacturing process thereof |
| CN104088940A (en) * | 2014-06-29 | 2014-10-08 | 奉化市飞天人精密模具设计有限公司 | Automobile shock absorber cover and heat treatment process thereof |
| CN104074900A (en) * | 2014-06-29 | 2014-10-01 | 奉化市飞天人精密模具设计有限公司 | Automobile shock absorber and heat treatment process thereof |
| CN107794441A (en) * | 2016-09-01 | 2018-03-13 | 株式会社Posco | The excellent high-strength spring steel material of hydrogen embrittlement and its manufacture method |
| CN107794441B (en) * | 2016-09-01 | 2019-08-16 | 株式会社Posco | The excellent high-strength spring steel material of hydrogen embrittlement and its manufacturing method |
| CN108239726A (en) * | 2016-12-23 | 2018-07-03 | 株式会社Posco | The excellent high-strength spring steel material of resistance to hydrogen embrittlement and its manufacturing method |
| CN108239726B (en) * | 2016-12-23 | 2020-04-10 | 株式会社Posco | Steel material for high-strength spring excellent in hydrogen embrittlement resistance and method for producing same |
| CN112840058A (en) * | 2018-08-21 | 2021-05-25 | 株式会社Posco | Wire rod and steel wire for spring having enhanced toughness and corrosion fatigue properties, and methods for manufacturing same |
| CN112840058B (en) * | 2018-08-21 | 2023-02-17 | 株式会社Posco | Wire rod and steel wire for spring having enhanced toughness and corrosion fatigue properties, and methods for manufacturing same |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100455691C (en) | 2009-01-28 |
| JP4423254B2 (en) | 2010-03-03 |
| KR100839726B1 (en) | 2008-06-19 |
| JP2007154240A (en) | 2007-06-21 |
| KR20070058345A (en) | 2007-06-08 |
| US20070125456A1 (en) | 2007-06-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1974825A (en) | High strength spring steel wire with excellent coiling properties and hydrogen embrittlement resistance | |
| CN1263880C (en) | High strength stainless steel wire excellent in ductility-toughness and modulus of rigidity and method for production thereof | |
| US8475605B2 (en) | Surface layer-hardened steel part and method of manufacturing the same | |
| US9796158B2 (en) | Steel for carburizing, carburized steel component, and method of producing the same | |
| TWI551693B (en) | Steel wire material for high strength spring with excellent hydrogen embrittlement resistance and its manufacturing method and high strength spring | |
| JP2013082963A (en) | Steel wire for bolt, bolt and manufacturing method therefor | |
| CN1827819A (en) | Steels for high-strength springs excellent in cold workability and quality stability | |
| CN1847438A (en) | Steel wire for cold-formed spring excellent in corrosion resistance and method for producing the same | |
| CN1806061A (en) | Steel parts for machine structure, material therefor, and method for manufacture thereof | |
| CN1811000A (en) | High strength spring steel having excellent hydrogen embrittlement resistance | |
| JP2010163689A (en) | Oil-tempered wire, method for manufacturing the same, and spring | |
| CN107406949B (en) | Steel wire for machine structural parts | |
| JP2007063584A (en) | Oil tempered wire and manufacturing method therefor | |
| JP2002146479A (en) | Wire rod for wire drawing having excellent twisting characteristic and its production method | |
| JP2017048459A (en) | Steel wire for machine structure component | |
| JP4423608B2 (en) | Hardened tool steel material | |
| CN1701127A (en) | High-strength steel product excelling in fatigue strength and process for producing the same | |
| CN1846010A (en) | Non-heat treated steel for soft-nitriding | |
| JP2018003106A (en) | Steel for machine structural use for cold working and production method therefor | |
| JP2010229469A (en) | High-strength wire rod excellent in cold working characteristic and method of producing the same | |
| JP2021143388A (en) | Martensitic stainless steel of high strength/high corrosion resistance excellent in durability and manufacturing method thereof | |
| CN1117171C (en) | Direct patenting high strength wire rod and method for producing same | |
| CN113710821B (en) | Steel wire and hot rolled wire rod | |
| JP5359582B2 (en) | Hardened tool steel material | |
| JP5189959B2 (en) | High strength cold-rolled steel sheet with excellent elongation and stretch flangeability |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090128 Termination date: 20201008 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |