CN101883873A - Steel for fracture split connecting rods - Google Patents
Steel for fracture split connecting rods Download PDFInfo
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- CN101883873A CN101883873A CN2008801185756A CN200880118575A CN101883873A CN 101883873 A CN101883873 A CN 101883873A CN 2008801185756 A CN2008801185756 A CN 2008801185756A CN 200880118575 A CN200880118575 A CN 200880118575A CN 101883873 A CN101883873 A CN 101883873A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- 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
- C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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Abstract
A steel for fracture split connecting rods, characterized by containing by mass C: 0.25 to 0.5%, Si: 0.01 to 2.0%, Mn: 0.50 to 2.0%, P: 0.015 to 0.080, S: 0.01 to 0.2%, V: 0.02 to 0.20%, Cr: 0.05 to 1.0%, Ti: 0.01 to 0.10% and N: 0.01% or below and having an f value of 0.003 to 0.04 as defined by the following formula and an average aspect ratio of sulfide inclusions of 15 or below: f = [Ti]-[N]x48/14 wherein [Ti] and [N] are contents (mass%) in steel of Ti and N respectively.
Description
Technical field
The present invention relates to be fit to be used to the steel of manufacturing as the employed connecting rod of parts such as motor car engine (being designated hereinafter simply as " connecting rod (con rod) ").
Background technology
In the oil engine of petrol motor and diesel engine etc., as to being connected between piston and the bent axle, the to-and-fro movement of piston passed to bent axle and convert the parts that rotatablely move to use connecting rod.Connecting rod is to have the parts that are used to be assembled to the rotund communicating pores on the bent axle, and in order to make its assembling and the dismounting when keeping in repair easy, the constituted mode of communicating pores part is for separating two nearly semicircles of (cutting apart) one-tenth.Directly be connected a side with piston among the isolating connecting rod and be called as con-rod only, all the other are called connecting rod cap.
Such connecting rod can be made in the following way: after for example respectively con-rod only and connecting rod cap being carried out forge hot, implement the processing on junction surface (mating face) again by cutting.Also have in the case,, also can implement steady brace (knock pin) processing as required for anti-sliding stop.But if implement this processing, then except output (yield quantity) reduction of material, also to go through a large amount of operations, therefore the such problem of cost rising is arranged.
Therefore practiced method is, one forge hot connecting rod, after implementing mechanical workout (communicating pores that is used to be assembled on the bent axle forms processing (perforate processing) and bolt hole processing etc.), carry out cold cracking and separate (cracking processing (fracture splittingprocess)) so that communicating pores partly becomes the mode of two nearly semicircles, clamp bent axle and chimeric surface of fracture (fracture surface) at last, assemble with bolted.According to this method, do not need surface of fracture is implemented the processing on the junction surface of being undertaken by cutting.
In addition, improving requirement for connecting rod with the machinability (machinability) of steel increases.But existing side by side of machinability and cracking performance is generally very difficult.Consider to reduce alloying constituent for machinability is improved, reduce the hardness of steel, but if reduce alloying constituent, then the ductility of steel improves, cracking performance reduces.Both are in the relation of these disappear those long (trade-off), are difficult to exist side by side.
For example, as the connecting rod steel of cracking performance excellence, known have a patent documentation 1～3.Patent documentation 1 proposes, the amount of control Si, V, P, N, Al, Ti, Nb, N, B etc. promotes brittle rupture (brittle fracture), and patent documentation 2 proposes, and the amount of control Si, V, P etc. promotes brittle rupture, patent documentation 3 proposes, and the amount of control Al, N etc. promotes brittle rupture.These patent documentations 1～3 are also pointed out in addition, then can promote brittle rupture if add Ti.But these connecting rods are poor with the steel machinability.For example with regard to patent documentation 1, in an embodiment, C measures than more than 0.5%, and alloying elements such as V and Cr are used superfluously.In addition, when the content of C etc. is suppressed, otherwise to use Ti to surpass 0.10%, guarantee cracking performance thus.In addition, patent documentation 2 and 3 uses Ti also to surpass 0.10% in an embodiment, and machinability is poor.
Patent documentation 1: No. 3235442 communique of patent
Patent documentation 2: No. 3416868 communique of patent
Patent documentation 3: No. 3416869 communique of patent
Summary of the invention
The present invention is conceived to above-mentioned situation and does, and its purpose is, a kind of cracking connecting-rod steel that cracking performance and machinability are existed side by side is provided.
In C amount is 0.25～0.5% steel, if do not add alloying element such as Ti, cracking performance extreme difference (with reference to the example of the Ti amount 0.002% of Fig. 1) then.Improve cracking performance for the fragility that improves steel, the interpolation of alloying element is (Ti with reference to Fig. 1 measures 0.125% example) effectively.But if heavy addition Ti, then machinability reduces.If consider from prior art, then cracking performance and machinability are in this those long relations that disappear, and the concrete countermeasure that is used to both are existed side by side does not propose as yet.
Present inventors' research with keen determination repeatedly in order to solve aforementioned problems, it found that, viewpoint from effective Ti (not forming the Ti of nitride), when arrangement Ti amount, effective Ti of denier just can make cracking performance be increased sharply, thereafter effect is saturated immediately, on the other hand, the reduction of machinability is mild, when effective Ti measured (f value) denier, machinability can reduce (with reference to Fig. 2) hardly, therefore measured the viewpoint of (f value) from effective Ti, if control Ti measures then cracking performance and machinability are existed side by side (with reference to Fig. 1), thereby finishes the present invention.
Promptly, cracking connecting-rod of the present invention has following some main idea with steel: contain the C:0.25～0.5% (meaning of quality %, down together), Si:0.01～2.0%, Mn:0.50～2.0%, P:0.015～0.080%, S:0.01～0.2%, V:0.02～0.20%, Cr:0.05～1.0%, Ti:0.01～0.10%, below the N:0.01%, surplus is made of iron and unavoidable impurities (inevitable impurities), f value by following formula (1) expression is more than 0.003,0.04 below, in the vertical section of the position of distance steel surface D/4 (D is the thickness or the diameter of steel), the every 1mm of sulfide-based inclusion that wide 1 μ m is above
2Have 100～4000, and the mean aspect ratio (aspect ratio length/width) of the sulfide-based inclusion more than this wide 1 μ m is below 15.
f＝[Ti]-[N]×48/14…(1)
[in the formula, [Ti] and [N] represents Ti in the steel and the content (quality %) of N respectively.]
Described steel also can also contain more than one that Zr:0.15% is following, Ca:0.005% is following, Mg:0.005% is following, Te:0.1% is following, REM:0.3% is following, Al:0.05% is following, Nb:0.05% is following, Cu:1.0% is following, Ni:1.0% is following, Mo:1.0% is following, Bi:0.1% is following etc.Also have, when containing Ca, recommending Al is below 0.01%.
Steel of the present invention, its preferred mode is below 0.08% for (a) Ti, and/or (b) below the V:0.10%.
According to the present invention, in C amount is 0.25～0.5% steel, because suitably controlled Ti amount, N amount, effective Ti amount (f value) etc., so can improve the connecting rod cracking performance of steel and the characteristic of this two aspect of machinability.
Description of drawings
Fig. 1 is the cracking performance of expression when making effective Ti amount (f value) variation and the graphic representation of the relation of machinability.
Fig. 2 is the graphic representation of the relation of the effective Ti amount of expression (f value) and cracking performance or machinability.
Fig. 3 (a) is the outline top view that is used for the test film of cracking performance test, and Fig. 3 (b) is the summary side elevation of described test film.
Fig. 4 is the device sketch chart that is used to illustrate the method for breaking test.
Fig. 5 is the outline top view of the test film before and after the tearing test.
Nomenclature
1 pressing machine
2 supporting stations
3a, 3b anchor clamps (holder)
4,5 chocks
6 test films
Embodiment
With regard to steel of the present invention, at first describe from its chemical ingredients composition.The chemical ingredients of steel of the present invention is composed as follows.
C：0.25～0.5％
C is used to guarantee intensity and is used to improve the needed element of cracking performance.Therefore the following of C amount is defined as 0.25%.The C amount is preferably more than 0.30%, more preferably more than 0.35%.But if the C amount is superfluous, then machinability reduces.Therefore the C amount is decided to be below 0.5%.The C amount is preferably below 0.48%, more preferably below 0.45%.
Si：0.01～2.0％
The deoxidant element (deoxidation element) of Si during as steel-smelting is useful.In order to bring into play this effect fully, the Si amount is preferably more than 0.01%, more preferably more than 0.05%, more preferably more than 0.10%.But if the Si amount is superfluous, then machinability and hot workability reduce.Therefore the Si amount is decided to be below 2.0%.The Si amount is preferably below 1%, more preferably below 0.7%.
Mn：0.50～2.0％
Mn (produce) when melting plays a role as deoxidation and desulfurization element (desulfurizing element), and is the element of the crackle when preventing to cast.In addition, Mn combines with S and forms sulfide-based inclusion (for example MnS etc.), and performance notched effect (notch effect) when cracking improves cracking performance.In order to give full play to these effects, the Mn amount is decided to be more than 0.50%.The Mn amount is preferably more than 0.70%, more preferably more than 0.90%.But if the Mn amount is superfluous, then generate bainite (bainite) in metal structure, machinability and cracking performance reduce.Therefore the Mn amount is decided to be below 2.0%.The Mn amount is preferably below 1.8%, more preferably below 1.5%.
P：0.015～0.080％
P makes toughness ductility (toughness and ductility) reduce at the inclined to one side plate of crystal boundary (segregate), be effective elements making in the cracking performance raising therefore.Therefore, in order to give full play to its effect, P is decided to be more than 0.015%.The P amount is preferably more than 0.020%, more preferably more than 0.030%.In addition, if the P surplus, then the hot workability of steel reduces.Therefore the P amount is decided to be below 0.080%.The P amount is preferably below 0.070%, more preferably below 0.060%.
S：0.01～0.2％
S forms sulfide-based inclusion (sulfide system inclusion, for example MnS etc.), and the notched effect during the performance cracking improves cracking performance, and also is the element that machinability is improved.In order to bring into play these effects fully, the S amount is decided to be more than 0.01%.The S amount is preferably more than 0.020%, more preferably more than 0.030%.But if the S amount is superfluous, then hot workability reduces.Therefore the S amount is decided to be below 0.2%.The S amount is preferably below 0.1%, more preferably below 0.07%.
V：0.02～0.20％
V is useful element being used to guarantee the intensity of steel and being used to make in the cracking performance raising.In order to bring into play this effect fully, the V amount is preferably more than 0.02%, more preferably more than 0.05%.But if the V amount too much, then its effect is saturated, and reduction and cost that superfluous in addition interpolation can cause machinability rise.Therefore the V amount is decided to be below 0.20%.The V amount is preferably below 0.19%, more preferably below 0.17%.
About the most preferred mode of V is below the V:0.10%.Even V below 0.10%, also can guarantee sufficient cracking performance, and add the reduction that V can prevent machinability with exceeding, therefore, do not improve element and also can guarantee sufficient machinability even do not add machinability such as Ca.The V amount more preferably below 0.08%, is preferably below 0.06% especially.
Cr：0.05～1.0％
Cr is the element that helps the intensity rising of endurance and fatigue strength etc.In order to bring into play its effect fully, the Cr amount is preferably more than 0.05%, more preferably more than 0.10%, more preferably more than 0.13%.But if the Cr amount is superfluous, then the machinability of steel reduces.Therefore the C amount is decided to be below 1.0%.The Cr amount is preferably below 0.90%, more preferably below 0.70%.
Ti：0.01～0.10％
Ti is important element on the cracking performance that is used to make steel improves.In order to give full play to its effect, the Ti amount is decided to be more than 0.01%.The Ti amount is preferably more than 0.018%, more preferably more than 0.020%.But if increase the Ti amount, then the machinability of steel reduces.If effective Ti amount described later (f value) is improved, then as long as adding the Ti cracking performance slightly will be increased sharply, even increase addition in addition, cracking performance can not improve yet.Therefore Ti exceeds can guarantee effective Ti amount described later (f value), preferably does one's utmost to reduce.Therefore Ti is decided to be below 0.10%.The Ti amount is preferably below 0.08%, more preferably below 0.07%, is preferably below 0.06% especially.
Below the N:0.01%
The present invention reduces the addition of Ti in order to improve machinability, be on the other hand to effectively utilize this a spot of Ti and cracking performance is improved effectively.N amount by in the restriction steel can suppress the formation of TiN, can effectively utilize a spot of Ti.Therefore the N amount is decided to be below 0.01%.The N amount is preferably below 0.009%, more preferably below 0.007%.Also have, the lower limit of measuring about N is not particularly limited, but can be for more than 0.002%.
Connecting rod of the present invention is formed as mentioned above with the basal component of steel, and surplus comes down to iron.But the unavoidable impurities that allows certainly to sneak into because of the situation of raw material, goods and materials, producing apparatus etc. is included in the steel.Connecting rod steel of the present invention in addition also can contain following arbitrary element as required.
That selects the group who is constituted below Zr:0.15%, below the Ca:0.005%, below the Mg:0.005%, below the Te:0.1%, below the REM:0.3% is at least a
Zr, Ca, Mg, Te and REM make sulfide-based inclusion (MnS etc.) balling, are to improving the useful element of cracking performance, can making in the steel as required and contain.The particularly easy more reduction of the many more cracking performances of Mn therefore in order to do one's utmost to avoid its influence, recommends to add Zr, Ca, Mg, Te or REM etc.In order to give full play to this effect, the Zr amount is preferably more than 0.01%, more preferably more than 0.05%, the Ca amount is preferably more than 0.0001%, more preferably more than 0.001%, the Mg amount is preferably more than 0.0001%, more preferably more than 0.001%, the Te amount is preferably more than 0.0001%, more preferably is more than 0.001%, the REM amount is preferably more than 0.0001%, more preferably more than 0.001%.
But the content of these elements is too much, and its effect is full, and causes cost and rise.In addition, if the Zr amount is superfluous, then machinability reduces.On the other hand, if Ca measures, Mg measures, Te measures surplus, then oxide based inclusion increases, and the fatigue strength of steel reduces.When therefore containing these elements, stipulate its upper limit in the above-described manner.The Zr amount more preferably (is preferably below 0.12%) below 0.13% especially, the Ca amount more preferably (is preferably below 0.003%) below 0.004% especially, the Mg amount more preferably (is preferably below 0.003%) below 0.004% especially, the Te amount more preferably (is preferably below 0.03%) below 0.05% especially, and the REM amount more preferably (is preferably below 0.05%) below 0.1% especially.Also have, Zr, Ca, Mg, Te and REM can distinguish interpolation separately, also can make up interpolation.
At least one that Al:0.05% is following and Nb:0.05% is following
Al, Nb are being effective elements aspect deoxidation and the grain refining (grain refining), help intensity to improve.In order to bring into play this effect fully, the Al amount is preferably and surpasses 0.01%, and more preferably more than 0.02%, the Nb amount is preferably more than 0.01%, more preferably more than 0.02%.Its effect also is saturated but add too much, therefore stipulates its upper limit in the above described manner.The Al amount more preferably (is preferably below 0.035%) below 0.04% especially, and the Nb amount more preferably (is preferably below 0.040%) below 0.045% especially.Also have,, the situation of adding Ca in steel is arranged in the present invention as above-mentioned.If add Ca, then cast gate stops up easily, and when therefore adding Ca, the Al amount is preferably below 0.01%, more preferably below 0.007%.
That selects the group who is constituted below Cu:1.0%, below the Ni:1.0%, below the Mo:1.0% is at least a
Cu, Ni and Mo are the elements that helps the intensity raising of steel, can make in the steel as required and contain.In order to give full play to its effect, the Cu amount is preferably more than 0.01%, more preferably is more than 0.05%, and the Ni amount is preferably more than 0.01%, more preferably is more than 0.1%, and the Mo amount is preferably more than 0.01%, more preferably more than 0.1%.But if the Cu amount is superfluous, flaw (mark) takes place in the steel surface when then making.In addition, Ni amount too much its effect also is saturated, and superfluous interpolation can cause cost and rise.In addition, if the Mo amount is superfluous, then the machinability of steel reduces.When therefore containing these elements, stipulate its upper limit in the above described manner.More preferably below 0.5%, more preferably below 0.5%, Mo measures more preferably below 0.7% the Ni amount Cu amount.
Below the Bi:0.1%
Bi is the element that helps machinability to improve.In order to bring into play its effect fully, the Bi amount is preferably more than 0.001%, more preferably more than 0.01%.But the addition of Bi too much its effect also is full, therefore stipulates its upper limit in the above described manner.The Bi amount is more preferably below 0.08%.
And the invention is characterized in that steel is formed modulation (draw up) after described scope, and suitably control effective Ti amount (f value).So-called effectively Ti amount, the meaning are to deduct the remaining Ti amount of TiN during the Ti from steel measures, and the situation that claims the f value is also arranged in this manual.From the viewpoint arrangement cracking performance of effective Ti amount, then effective Ti of denier just can make cracking performance be increased sharply, and effect is saturated immediately thereafter.On the other hand, the reduction of machinability is mild, and when effective Ti measured (f value) denier, machinability can reduce hardly.Therefore, need in the scope, will guarantee as far as possible that the Ti that cracking performance is increased sharply needed effective Ti amount (f value) is used, and can improve cracking performance and machinability both sides MIN.
Effectively Ti amount (f value) is provided by following formula (1).In order positively to improve cracking performance, effectively Ti amount (f value) is more than 0.003, is preferably more than 0.005, more preferably more than 0.008.But if effectively Ti amount (f value) becomes big, then the addition of Ti increases, and machinability reduces easily.Therefore effectively Ti amount (f value) is preferably below 0.04, more preferably below 0.02, is preferably below 0.015 especially.
f＝[Ti]-[N]×48/14?…?(1)
[in the formula, [Ti] and [N] represents Ti in the steel and the content (quality %) of N respectively.]
In most preferred mode, in the described lower value that positively satisfies effective Ti amount (f value), guarantee on the basis of cracking performance, be absorbed in the upper limit that effective Ti measures Ti content in the upper limit of (f value) and the steel as far as possible.So just, can both positively improve cracking performance, can make machinability reach the highest again.When effectively Ti content was minimum in Ti amount (f value) and the steel, effectively Ti amount (f value) was below 0.015, and Ti content is below 0.06% in the steel.
In addition, with in the steel, need reduce the long-width ratio of sulfide-based inclusion (for example MnS etc.) at connecting rod of the present invention.Sulfide-based inclusion through rolling and forge hot meeting to rolling direction with forge direction ductility.If the sulfide-based inclusion of this extension exists vertical (longitudinaldirection is extending on the vertical direction with respect to cracking face) when the cracking of steel, then along with the progress of crackle, peel off between sulfide-based inclusion and the metallic matrix, the mitigation of stress takes place.Consequently, brittle fracture is hindered, and toughness ductility value improves, the reduction that brings cracking performance.With respect to this, so suppress the extension of sulfide-based inclusion, dwindle long-width ratio and make it balling, then vertically during cracking, the stress of the crackle front end that takes place at the periphery of sulfide-based inclusion increases, and brittle fracture obtains promoting.Consequently can reduce amount of plastic deformation, the cracking performance of steel improves.In addition, to improve effect be that 1 μ m obtains performance when above at the width of sulfide-based inclusion to the cracking performance that brings of the balling of this sulfide-based inclusion.If the width of sulfide-based inclusion is too small, then sulfide-based inclusion self fracture can not promote the brittle fracture of steel.
If performance is used to bring into play size and the form that such cracking performance improves the sulfide of effect quantitatively, then be as follows, promptly in steel of the present invention, in the vertical section of the position of distance steel surface D/4 (D is the thickness or the diameter of steel), the every 1mm of sulfide-based inclusion that wide 1 μ m is above
2Exist more than 100, the arithmetical av (arithmetic average, mean aspect ratio) of the mean aspect ratio (length/width) of the sulfide-based inclusion that this wide 1 μ m is above is below 15.
Mean aspect ratio is preferably below 10, more preferably below 8, is preferably below 6 especially.Mean aspect ratio is preferred near 1 more more, and lower limit is not particularly limited, and can be (or more than 3) more than 2.
The every 1mm of number of the sulfide-based inclusion that wide 1 μ m is above
2Be preferably more than 300, more preferably more than 400.But many if the number of sulfide-based inclusion becomes, then be easy to generate the disadvantage of crackle etc. when rolling and during forge hot.Therefore recommend the above every 1mm of sulfide-based inclusion of wide 1 μ m
2Be below 4000.Preferred every 1mm
2Be below 3000, more preferably below 2500.
Also have, the what is called among the present invention " sulfide-based inclusion " mainly is meant MnS, but also comprises other sulfide and complex sulfide (complex sulfide).The value of the width of sulfide-based inclusion and mean aspect ratio (length/width) and number thereof in addition is in the vertical section of the position of distance steel surface D/4 (D is the thickness or the diameter of steel), with 1000 times observation multiplying powers to 1mm
2Field of view carry out observation by light microscope and the value of trying to achieve.
Also have, suitably set rolling condition according to the addition of Mn, S and inclusion balling element (Zr, Ca, Mg, Te and REM etc.), can be in specialized range with the size of sulfide-based inclusion and morphology Control.With regard to rolling condition, recommend to select rolling temperature since the scope more than 1000 ℃, select rolling end temp from the scope more than 850 ℃.Improve rolling beginning temperature and rolling end temp, the long-width ratio of sulfide-based inclusion is easy more to diminish, satisfy prescribed value easily more, in addition, because sulfide-based inclusion serves as that nuclear is separated out with the precipitate of the Ti of TiC and TiN etc. easily, so when steel contained Ti, the sulfide-based inclusion that long-width ratio is little was separated out in a large number.
Embodiment
Below, enumerate embodiment and be described more specifically the present invention, but the present invention not limiting by following embodiment certainly, the scope of aim described later can certainly be changed enforcement before can meeting, and these all are included in the technical scope of the present invention.
Experimental example 1
Follow the steel of the chemical constitution shown in the common melting method fusion table 1, cast, after the cogging (slabbing), begin the rolling of 1050 ℃ of temperature, 900 ℃ of end temps, obtain
Bar steel.
Investigate the characteristic of resulting bar steel as follows.
(1) sulfide-based inclusion
In the vertical section of the position of distance bar steel surface D/4 (D is a diameter), observe 1mm with opticmicroscope (1000 times)
2The visual field, count the number of the above sulfide-based inclusion of wide 1 μ m.Measuring this width in addition is the long-width ratio of the above sulfide-based inclusion of 1 μ m, tries to achieve its arithmetical av.
(2) cracking performance (dimensional change)
After resulting rod cuts into suitable length more in the experimental example, be heated to 1200 ℃ of temperature, concora crush, is implemented air cooling and is handled after forging processing to thick 25mm.Cut resulting platysome, be processed into test film shown in Figure 3.Among Fig. 3, (a) top view of expression test film, (b) side-view of expression test film.A is an otch, and b is a bolt hole, and c is the arrow of expression rolling direction.Test film is the tabular of 65mm * 65mm * thick 22mm, and central authorities stamp out
Hole cylindraceous.Be provided with otch a (R0.2mm, dark 0.5mm) in the end in the hole of central authorities.In addition, be provided with bolt hole b in test film upper edge rolling direction
As shown in Figure 4, in the hole of the central authorities of test film 6, anchor clamps 3a, 3b are arranged, carry out the cracking of test film with extrusion speed: 270mm/s by being arranged on the pressure testing machine (1600t pressing machine).Also have, because the angle of wedge of chock 4 and 5 is 30 °, the crack velocity of test film is calculated as about 150mm/s.Then as shown in Figure 5, make aperture difference before and after the cracking (dimensional change L2-L1) takes place in difference of holediameter, this dimensional change be 0.15mm following be evaluated as the cracking performance excellence.Also have following this standard of dimensional change 0.15mm to be equal to the C70S6 of the DIN specification of using in Europe.
(3) machinability (life tools)
After the cut surface of the bar steel that obtains in the experimental example carried out milling cutter processing, on this milling cutter machined surface, carry out perforate processing, process distance (combined length) until tool failure (breakage) or melting loss (melting damage) and mensuration processing with following condition.
Cutting tool: SKH51 (
Straight shank drill)
Cutting speed: 30m/min
The amount of feed: 0.15mm/rev
Hole depth: 30mm
Lubricating status: dry type
Position of opening: D/4 (D is the diameter of bar steel)
Processing distance L with the steel grade A1 of table 1
A1Being standard, is the processing distance L that relative value is put each bar steel in order with value at this moment, the appraisal tool life-span.
Life tools=L/L
A1
The result is presented among table 1 and Fig. 1, Fig. 2.
[table 1]
* Al:0.01% is following is inevitably to measure, and is designated as "-"
By table 1, Fig. 1, Fig. 2 as can be known, if reduce the Ti addition, then can improve cracking performance and machinability both sides while guarantee effective Ti amount (f value).
Experimental example 2
Except the steel that uses the chemical constitution shown in the table 2,3, all identical with experimental example 2.About life tools, in each group of B～H, J, with life tools of steel grade of not adding Ti as 1, with the relative value representational tool life-span of this moment.
The result is presented in table 4～7.Also have, in table 7, also shown in the lump with life tools life tools of steel grade J1 as 1 o'clock steel grade A1, thus can with contain the life tools that more V reaches the A group about 0.160% and compare.
[table 2]
※ Al:0.01% is following to be inevitably to measure, and is designated as "-"
[table 3]
※ Al:0.01% is following to be inevitably to measure, and is designated as "-"
[table 4]
[table 5]
[table 6]
[table 7]
Suitably controlled C, Si, Mn etc. each become to be grouped into and effectively steel grade B4, B5, B7, C2～4, D2, E2, E3, F2, G2～4, the dimensional change after the H2 cracking of Ti amount (f value) be below the 0.15mm, the cracking performance excellence, and life tools also excellence.Demonstrate good cracking performance as J3～J10 optimal way of the present invention, that contain V in the scope below 0.10% in addition, even and do not contain machinability such as Ca and improve element, life tools are also excellent.
Experimental example 3
Use the steel grade H2 shown in the table 2, make rolling beginning temperature and rolling end temp shown in following table 8, all identical in addition with experimental example 1.
The result is presented in the table 8
[table 8]
As shown in Table 8, improve rolling beginning temperature and rolling end temp more, can dwindle the long-width ratio of sulfide-based inclusion more.
Claims (7)
1. cracking connecting-rod steel, it is characterized in that, in quality % contain C:0.25～0.5%, Si:0.01～2.0%, Mn:0.50～2.0%, P:0.015～0.080%, S:0.01～0.2%, V:0.02～0.20%, Cr:0.05～1.0%, Ti:0.01～0.10%, below the N:0.01%, surplus is iron and unavoidable impurities
By the f value of following formula (1) expression is more than 0.003 below 0.04,
In the vertical section of the position of distance steel surface D/4, width is the above every 1mm of sulfide-based inclusion of 1 μ m
2Have 100～4000, and this width is that the mean aspect ratio of the above sulfide-based inclusion of 1 μ m is that length/width is below 15, wherein, D is the thickness or the diameter of steel,
f＝[Ti]-[N]×48/14…(1)
In the formula, [Ti] and [N] represents Ti in the steel and the mass percentage content of N respectively.
2. cracking connecting-rod steel according to claim 1 is characterized in that, is below 0.08% in quality % Ti.
3. cracking connecting-rod steel according to claim 1 is characterized in that, below quality % V:0.10%.
4. cracking connecting-rod steel according to claim 1, it is characterized in that at least a element of selecting also containing below Zr:0.15%, below the Ca:0.005%, below the Mg:0.005%, below the Te:0.1%, below the REM:0.3% in quality %.
5. cracking connecting-rod steel according to claim 1 is characterized in that, in quality % also contain below the Al:0.05% and below the Nb:0.05% at least a element.
6. cracking connecting-rod steel according to claim 1 is characterized in that, at least a element of selecting also containing below Cu:1.0%, below the Ni:1.0%, below the Mo:1.0% in quality %.
7. cracking connecting-rod steel according to claim 1 is characterized in that % also contains below the Bi:0.1% in quality.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007312523 | 2007-12-03 | ||
| JP2007-312523 | 2007-12-03 | ||
| PCT/JP2008/071702 WO2009072445A1 (en) | 2007-12-03 | 2008-11-28 | Steel for fracture split connecting rods |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101883873A true CN101883873A (en) | 2010-11-10 |
| CN101883873B CN101883873B (en) | 2012-10-31 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008801185756A Expired - Fee Related CN101883873B (en) | 2007-12-03 | 2008-11-28 | Steel for fracture split connecting rods |
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| Country | Link |
|---|---|
| US (1) | US20100266439A1 (en) |
| EP (1) | EP2216423B1 (en) |
| JP (1) | JP4264460B1 (en) |
| KR (1) | KR20100070386A (en) |
| CN (1) | CN101883873B (en) |
| BR (1) | BRPI0819104A2 (en) |
| WO (1) | WO2009072445A1 (en) |
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| CN107406941A (en) * | 2015-03-09 | 2017-11-28 | 新日铁住金株式会社 | Hot-strip and steel part |
| CN108138284A (en) * | 2015-10-19 | 2018-06-08 | 新日铁住金株式会社 | Hot-strip and steel part |
| CN109804097A (en) * | 2016-09-29 | 2019-05-24 | 新日铁住金株式会社 | Hot-strip and steel part |
| CN110616363A (en) * | 2018-06-20 | 2019-12-27 | 宝山钢铁股份有限公司 | Medium-carbon non-quenched and tempered expansion-fracture connecting rod steel and manufacturing method thereof |
| CN111936653A (en) * | 2018-04-20 | 2020-11-13 | 日本制铁株式会社 | Steel, mechanical part and connecting rod |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5432590B2 (en) * | 2009-05-20 | 2014-03-05 | 株式会社神戸製鋼所 | Hot forged parts excellent in fracture splitting property, manufacturing method thereof, and automotive internal combustion engine parts |
| WO2012157455A1 (en) | 2011-05-19 | 2012-11-22 | 住友金属工業株式会社 | Untempered steel and untempered steel member |
| JP5703991B2 (en) * | 2011-06-24 | 2015-04-22 | スズキ株式会社 | Connecting rod fracture splitting method and apparatus |
| JP5778055B2 (en) * | 2012-02-15 | 2015-09-16 | 新日鐵住金株式会社 | ROLLED STEEL FOR HOT FORGING, HOT FORGING SEMICONDUCTOR, COMMON RAIL AND PROCESS FOR PRODUCING THE SAME |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2742448B1 (en) * | 1995-12-14 | 1998-01-16 | Ascometal Sa | STEEL FOR THE MANUFACTURE OF SECABLE MECHANICAL PARTS AND OBTAINED PART |
| JP3235442B2 (en) | 1995-12-26 | 2001-12-04 | 住友金属工業株式会社 | High strength, low ductility non-heat treated steel |
| JP3416868B2 (en) | 1998-01-07 | 2003-06-16 | 住友金属工業株式会社 | High-strength, low-ductility non-heat treated steel with excellent machinability |
| JPH11236643A (en) * | 1998-02-25 | 1999-08-31 | Sumitomo Metal Ind Ltd | Low ductility non-tempering steel |
| JP3416869B2 (en) | 1998-04-06 | 2003-06-16 | 住友金属工業株式会社 | Low ductility non-heat treated steel with excellent machinability |
| JP3671688B2 (en) * | 1998-08-28 | 2005-07-13 | 株式会社神戸製鋼所 | Non-heat treated steel for hot forging for fracture split type connecting rods with excellent fracture splitting |
| JP3473500B2 (en) * | 1999-06-04 | 2003-12-02 | 住友金属工業株式会社 | Low ductility non-heat treated steel |
| JP3536770B2 (en) * | 2000-03-17 | 2004-06-14 | 住友金属工業株式会社 | Non-heat treated steel |
| JP4115737B2 (en) * | 2002-04-12 | 2008-07-09 | 山陽特殊製鋼株式会社 | Machine structural steel using fine sulfides with excellent machinability and fracture splitting |
| JP3887271B2 (en) * | 2002-05-29 | 2007-02-28 | 大同特殊鋼株式会社 | High-strength non-tempered steel that can be separated by breakage and intermediate products |
| JP4797673B2 (en) * | 2006-02-10 | 2011-10-19 | 住友金属工業株式会社 | Hot forging method for non-tempered parts |
| JP4268194B2 (en) * | 2006-03-15 | 2009-05-27 | 株式会社神戸製鋼所 | Rolled material for fracture separation type connecting rod excellent in fracture separation, hot forged parts for fracture separation type connecting rod excellent in fracture separation, and fracture separation type connecting rod |
| CN101405418B (en) * | 2006-03-15 | 2012-07-11 | 株式会社神户制钢所 | Rolled material for fracture split connecting rod excelling in fracture splittability, hot forged part for fracture split connecting rod excelling in fracture splittability, and fracture split connect |
| JP5068087B2 (en) * | 2007-02-23 | 2012-11-07 | 株式会社神戸製鋼所 | Steel for fracture split type connecting rods with excellent fracture splitability and machinability |
-
2008
- 2008-11-07 JP JP2008286237A patent/JP4264460B1/en not_active Expired - Fee Related
- 2008-11-28 US US12/740,492 patent/US20100266439A1/en not_active Abandoned
- 2008-11-28 EP EP08858217.6A patent/EP2216423B1/en not_active Not-in-force
- 2008-11-28 WO PCT/JP2008/071702 patent/WO2009072445A1/en active Application Filing
- 2008-11-28 BR BRPI0819104-2A patent/BRPI0819104A2/en not_active Application Discontinuation
- 2008-11-28 KR KR1020107012205A patent/KR20100070386A/en active Search and Examination
- 2008-11-28 CN CN2008801185756A patent/CN101883873B/en not_active Expired - Fee Related
Cited By (7)
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| CN107406941A (en) * | 2015-03-09 | 2017-11-28 | 新日铁住金株式会社 | Hot-strip and steel part |
| CN107406941B (en) * | 2015-03-09 | 2019-05-03 | 新日铁住金株式会社 | Hot-strip and steel part |
| CN108138284A (en) * | 2015-10-19 | 2018-06-08 | 新日铁住金株式会社 | Hot-strip and steel part |
| CN109804097A (en) * | 2016-09-29 | 2019-05-24 | 新日铁住金株式会社 | Hot-strip and steel part |
| CN111936653A (en) * | 2018-04-20 | 2020-11-13 | 日本制铁株式会社 | Steel, mechanical part and connecting rod |
| CN110616363A (en) * | 2018-06-20 | 2019-12-27 | 宝山钢铁股份有限公司 | Medium-carbon non-quenched and tempered expansion-fracture connecting rod steel and manufacturing method thereof |
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Also Published As
| Publication number | Publication date |
|---|---|
| JP4264460B1 (en) | 2009-05-20 |
| EP2216423A4 (en) | 2014-12-10 |
| EP2216423B1 (en) | 2015-09-30 |
| CN101883873B (en) | 2012-10-31 |
| BRPI0819104A2 (en) | 2015-07-07 |
| WO2009072445A1 (en) | 2009-06-11 |
| EP2216423A1 (en) | 2010-08-11 |
| KR20100070386A (en) | 2010-06-25 |
| US20100266439A1 (en) | 2010-10-21 |
| JP2009155724A (en) | 2009-07-16 |
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