CN1942597A - Nonoriented electromagnetic steel sheet excellent in blankability and magnetic characteristics after strain removal annealing, and method for production thereof - Google Patents

Abstract

A nonoriented electromagnetic steel exhibiting excellent blankability and also exhibiting good and stable iron loss after the annealing for strain removal, which has a chemical composition, in mass %, that Si: 1.5 % or less, Mn: 0.4 to 1.5 %, Sol.Al: 0.01 to 0.04 %, Ti: 0.0015% or less, N: 0.0030 % or less, S: 0.0010 to 0.0040%, Sn: 0.01 to 0.50%, B: an amount satisfying 0.5 <= B/N <=1.5, and the balance: Fe and inevitable impurities, wherein 10 % or more, in terms of the number of pieces, of the sulfide containing Mn precipitates in a composite form with a B precipitate, and wherein it has a crystal grain diameter of 30 m or less and exhibits a crystal grain diameter of 50 m or more after the annealing for strain removal at 750 DEG C for 2 hours; and a method for producing the above nonoriented magnetic steel which comprises holding a slab for hot rolling at a temperature of 1150 to 1250 DEG C for five minutes or more, subsequently holding it at a temperature of 1050 DEG C or higher and lower than 1150 DEG C for 15 minutes or more, and immediately thereafter, subjecting the resultant slab to a hot rolling with a finishing output temperature T ( DEG C) of T >= 900 - 1000 x Sn [mass %].

Description

The non-oriented electromagnetic steel sheet having of the excellent in magnetic characteristics after stamping-out processibility and the stress relieving and manufacture method thereof

Technical field

The present invention relates to as the core material of electric installation and non-oriented electromagnetic steel sheet having and the manufacture method thereof used, the particularly non-oriented electromagnetic steel sheet having and the manufacture method thereof of the excellent in magnetic characteristics after stamping-out processibility and the stress relieving.

Background technology

In recent years, because the raising of energy-conservationization of global electric installation, as the core material of rotary machine and the non-oriented electromagnetic steel sheet having that uses also requires more high performance characteristic, for the motor of the electric product that is called as " high-level efficiency type ", use to increase gradually Si, Al content with improve intrinsic resistance and crystal particle diameter become big senior starting material.On the other hand, for the motor of general type, though also constantly require performance to improve, because the restriction of cost is relatively stricter, therefore present situation is to be difficult to image height efficient type to replace to senior starting material like that.

As the desired steel plate of general type, be Si be below 1.5% and the grain growing when promoting to implement stress relieving in motor chip stamping-out processing back so that its iron loss obtains the starting material of tremendous improvement.In addition, recently, the demand client that the waste material that is produced during with the chip stamping-out is used for the raw material of foundry goods increases, and from the viewpoint of the castibility of guaranteeing waste material, the Al content that has produced steel plate is lower than 0.05% requirement.

Grain growing when improving stress relieving, importantly reduce the precipitate of sneaking into inevitably in the steel or make it innoxious, the material design that Al is lower than 0.05% non-oriented electromagnetic steel sheet having can roughly be divided into two classes, one of them is from opening the method that clear 54-163720 communique is seen as the spy, B to Al deoxidized steel (solubilized Al (being Sol.Al) is about 0.02%) interpolation about 0.002%, with the BN of generation, thereby suppress separating out to the deleterious AlN of grain growing as nitride.

Another kind of method is from opening the method that flat 7-150248 communique is seen as the spy, by controlling the SiO of the oxide compound that is contained in the Si deoxidized steel (Sol.Al≤0.001%) ₂With the ratio of MnO, thereby suppress the deleterious extensibility inclusion of grain growing.As this strategy, open the Mn/Si that once disclosed composition of steel in the flat 6-73510 communique the spy and be controlled at 0.2～1.0.

As being accompanied by nitride that deoxidation generates or oxide compound and minimizing or the innoxious method of improving magnetic by sulfide by suitable control like this, once disclose as follows: for example the spy opens in the clear 58-117828 communique for the magnetic effect that improves S is defined as method below 0.005%; The spy opens in the clear 58-164724 communique and to add Ca or rare earth element with the fixing method of S when the S that contains 0.01～0.02%; And special opening in the flat 4-63228 communique by S being made as below 0.0050% and the Heating temperature of slab being made as below 1100 ℃ to prevent MnS fine method of separating out in hot rolling.

Summary of the invention

Further requiring to reduce under the situation of iron loss, adopting aforesaid method to be difficult to fully and manufacturing stably.The present invention makes in view of the above-mentioned problems, by being conceived to, be desirable to provide the steel plate that grain growing is good and iron loss is low and magneticflux-density is high after the stress relieving to suppress the improvement scheme that separating out of AlN is the element S of sneaking into inevitably in the B that adds of purpose and the steel.

The present invention makes in order to solve above-mentioned problem, and its main contents are as follows:

(1) a kind of non-oriented electromagnetic steel sheet having is characterized in that: in quality % contain below the Si:1.5%, Mn:0.4～1.5%, Sol.Al:0.01～0.04%, below the Ti:0.0015%, below the N:0.0030%, S:0.0010～0.0040%, B: with B/N count 0.5～1.5 and remainder form by Fe and unavoidable impurities; And separate out with the B precipitate is compound containing counting more than 10% among the sulfide of Mn with the number ratio.

(2) a kind of non-oriented electromagnetic steel sheet having, it is characterized in that: in quality % contain below the Si:1.5%, Mn:0.4～1.5%, Sol.Al:0.01～0.04%, below the Ti:0.0015%, below the N:0.0030%, S:0.0010～0.0040%, B: with B/N count 0.5～1.5 and remainder by Fe and unavoidable impurities and form, wherein, the crystal particle diameter of steel plate is below the 30 μ m, and the crystal particle diameter after 750 ℃ * 2 hours the stress relieving is more than the 50 μ m.

(3) according to (1) or (2) described non-oriented electromagnetic steel sheet having, it is characterized in that: MnS, Cu ₂The total distribution density of S and complex sulfide thereof is 3.0 * 10 ⁵Individual/mm ²Below.

(4) according to any one the described non-oriented electromagnetic steel sheet having in (1)～(3), it is characterized in that: the distribution density of the Ti precipitate of the discontented 0.1 μ m of diameter is 1.0 * 10 ³Individual/mm ²Below.

(5) according to any one the described non-oriented electromagnetic steel sheet having in (1)～(4), it is characterized in that: also contain with quality % add up among 0.01～0.50% Sn, Cu, the Ni more than a kind or 2 kinds and/or among 0.001～0.5% REM, Ca, the Mg more than a kind or 2 kinds.

(6) manufacture method of any one the described non-oriented electromagnetic steel sheet having in manufacturing (1)～(5), it is characterized in that: when then imposing final annealing in system steel, hot rolling, pickling, after cold rolling, heat for the hot rolled slab, stop more than 5 minutes 1150 ℃～1250 ℃ scopes, then more than 1050 ℃ but be lower than 1150 ℃ scope and stop more than 15 minutes, carry out hot rolling then immediately.

(7) according to the manufacture method of any one described non-oriented electromagnetic steel sheet having in (1)～(6), it is characterized in that: when then imposing final annealing at system steel, hot rolling, pickling, after cold rolling, hot rolled finish to gauge temperature out is set at more than 800 ℃.

(8) according to the manufacture method of (6) described non-oriented electromagnetic steel sheet having, it is characterized in that: for the steel plate that contains Sn, above-mentioned hot rolled finish to gauge temperature out T (℃) be set at T 〉=900-1000 * Sn (quality %).

Embodiment

Present inventors face such problem: for Si is steel below 1.5%, even the element S that will unavoidably sneak into reduces to about 0.0010% and as special open in the flat 4-63228 communique like that with the temperature low temperatureization of slab heating to below 1100 ℃, the iron loss after the stress relieving still fluctuates and instability.Its reason is found through investigation, although S amount and slab heating temperature are low, still tiny and be scattered here and there in large quantities MnS, Cu in the steel ₂Therefore S and complex sulfide thereof have significantly suppressed the grain growing after the stress relieving.Further in detail observing and find, is sphere about 0.1～0.3 μ m though these sulfide form diameters, and it is Ti precipitate about 0.05 μ m that its centre includes equivalent diameter.Known that it is because add the TiN that pines for separating out at first to hot rolling slab and slightly be scattered here and there and separate out sulfide as nuclear after casting that sulfide becomes such reason of separating out form.

In order to open this situation, present inventors are conceived to compare with TiN the sulfide of fast growth and easy thickization.That is, and be that the compound present situation of separating out sulfide of nuclear is opposite with TiN, attempting with sulfide is that nuclear makes that TiN is compound to separate out, and found that to obtain stable low iron loss.And learn, the BN that generates for fixing residue N described later, sulfide is compound separates out by making, and also can obtain stable low iron loss, thereby has finished the present invention.Below, just reach experimental result of the present invention and narrate.

(experiment 1)

Adopt breadboard vacuum melting furnace, made the steel disc that contains C:0.003%, Si:0.6%, Mn:0.1～0.8%, Sol.Al:0.03%, Ti:0.0012%, N:0.0021%, S:0.0005～0.0025%, B:0.0020%, Sn:0.08% in quality %.These steel discs 1200 ℃ of down insulations 20 minutes, were cooled to 1100 ℃ and be incubated 30 minutes through 10 minutes, carrying out hot rolling then, to make thickness of slab be 2.5mm, and being cold-rolled to thickness of slab after pickling is 0.50mm.

For the cold-reduced sheet that obtains like this, after carrying out the final annealing in 10 seconds under 800 ℃, under 750 ℃, impose 2 hours stress relieving, measure crystal particle diameter and iron loss.Its result is as shown in table 1 like that, is more than 0.4% and S is 0.0012%, 0.0025% test portion 8,9,11,12 for Mn, and the crystal particle diameter after the stress relieving is more than the 50 μ m, and has obtained good iron loss.

Secondly, carry out precipitate for the test portion after the stress relieving and observe, in having obtained 8,9,11,12 test portion of good iron loss, observed the sulfide that contains Mn and separated out with number ratio more than 10% and the compound of B precipitate.On the other hand, in relatively poor other test portion of iron loss, the diameter of having observed a large amount of precipitates of thinking B is lower than the tiny precipitate of 0.1 μ m.

For being more than 0.4% by Mn like this and S is the effect of improving of grain growing after 0.0012%, 0.0025% stress relieving that realizes and iron loss, consider as follows.At first, begin to separate out temperature by what improve that Mn measures the MnS that raises.Make that thus MnS separates out than BN when hot rolling is heated, and the BN that separates out thereafter is nuclear and compound separating out can be thought the generation that can suppress the tiny precipitate of B thus with MnS in advance, can obtains grain growing and iron loss after the good stress relieving.

On the other hand, when Mn is lower than 0.4%, in the BN precipitation phase, MnS separate out insufficient or when S is 0.0005%, the amount of separating out of MnS itself is few, therefore can think, under above-mentioned any situation BN to separate out nuclear all insufficient, B separates out separately and slightly, does not improve the characteristic after the stress relieving thus.

Table 1

Symbol	Mn	S	Crystal particle diameter (μ m)	W15/50 (W/kg)	The compound ratio (%) of separating out	Remarks
							(％)
	1	0.1							0.0005	30	4.88	0	Comparative example
2			0.0012	25	5.02	0	Comparative example
	3							0.0025	19	5.21	5	Comparative example
4			0.2	0.0005	34	4.78	5						Comparative example
	5	0.0012						29	4.89	5	Comparative example
6				0.0025	21	5.05	5					Comparative example
	7	0.4						0.0005	35	4.72	40		Comparative example
8			0.0012	62	3.65	30	Example
	9							0.0025	54	4.03	20	Example
10			0.8	0.0005	43	4.55	50						Comparative example
	11	0.0012						65	3.51	45	Example
12				0.0025	58	3.88	40					Example

(experiment 2)

Adopt breadboard vacuum melting furnace, make the steel disc that contains C:0.0034%, Si:0.75%, Mn:0.15～0.72%, Sol.Al:0.019%, Ti:0.0008～0.0017%, N:0.0018%, S:0.0023%, B:0.0025%, Sn:0.03%, Cu:0.01%, Ni:0.02% in quality %.These steel discs 1200 ℃ of down insulations 5 minutes, are cooled to 1100 ℃ and be incubated 30 minutes, and carrying out hot rolling then, to make thickness of slab be 2.7mm, and being cold-rolled to thickness of slab after pickling is 0.50mm.For the cold-reduced sheet that obtains like this, after carrying out the final annealing in 10 seconds under 800 ℃, under 750 ℃, impose 2 hours stress relieving, observe the precipitate and the crystal particle diameter of steel plate, measure iron loss simultaneously.

Its result is as shown in table 2 like that, is more than 0.4% and Ti is that the sulfide density after the stress relieving is 3.0 * 10 in the test portion 4,5,7,8 below 0.0015% at Mn ⁵Below, the average crystalline particle diameter is more than the 50 μ m, obtained good iron loss.In these test portions, confirmed that diameter is that the spherical sulfide of 0.2～0.3 μ m is more and have a plurality of equivalent diameters to be lower than the separating out of tiny Ti precipitate of 0.1 μ m in its periphery.On the other hand, in Mn was low to moderate 0.15% test portion 1～3, the sulfide density after the stress relieving was higher 4.5 * 10 ⁵Individual/mm ²More than, the average crystalline particle diameter is also little below 35 μ m, and iron loss is relatively poor.The diameter of the sulfide of being seen in these test portions is can confirm that wherein pericardium contains the Ti precipitate to 0.1 μ m and in the sulfide at majority for a short time.In addition, for Mn be more than 0.4%, Ti surpasses 0.0015% test portion 6 and 9, the sulfide density after the stress relieving is also high to 3.8 * 10 ⁵Individual/mm ²More than, the average crystalline particle diameter also is that iron loss is also poor below the 45 μ m.In these test portions, fluctuate in the relative broad range of the diameter of sulfide below 0.05～0.3 μ m, with the complex morphological of Ti precipitate be in its periphery or at central part, also be diversified.In addition, equivalent diameter is lower than the distribution density of the tiny Ti precipitate of 0.1 μ m, all is low to moderate to be lower than 1.0 * 10 in any test portion ³Individual/mm ²

Like this, for being set at the effect that realizes below 0.0015%, can consider as follows by Mn is brought up to more than 0.4% and with Ti.At first, by improve the Mn amount make MnS begin separate out temperature and raise, on the other hand by reduce Ti make TiN begin separate out temperature and reduce.Secondly thus, with the common reversed in order of separating out, MnS separates out than TiN in advance,, can think that beginning to separate out MnS that temperature raise separates out and grow under 1200 ℃ of hot rolling heating leading portion; On the other hand, beginning to separate out TiN that temperature reduced serves as that nuclear is separated out with the thick MnS that has changed under 1100 ℃ of hot rolling heating back segment.

Table 2

Symbol	Mn	Ti	Sulfide density is (individual/mm 2)	Ti precipitate density is (individual/mm 2)	Crystal particle diameter (μ m)	W15/50 (W/kg)	Remarks
								(％)
	1	0.15								0.0008	4.5×10 5	＜1.0×10 3	35	4.51	Comparative example
2			0.0013	4.8×10 5	＜1.0×10 3	32	4.55	Comparative example
	3								0.0017	5.4×10 5	＜1.0×10 3	30	5.02	Comparative example
4			0.42	0.0008	2.8×10 5	＜1.0×10 3	55	4.02							Example
	5	0.0013							2.7×10 5	＜1.0×10 3	53	4.05	Example
6				0.0017	3.9×10 5	＜1.0×10 3	44	4.34						Comparative example
	7	0.72							0.0008	1.8×10 5	＜1.0×10 3	65	3.88		Example
8			0.0013	1.9×10 5	＜1.0×10 3	62	3.94	Example
	9								0.0017	3.8×10 5	＜1.0×10 3	45	4.33	Comparative example

(experiment 3)

Secondly, in order to investigate the influence of hot rolled heating condition, the Mn that uses experiment 1 is 0.4%, S is 0.0025% steel disc, implement the hot rolling heating of following 2 levels: be incubated 60 minutes down or be incubated 60 minutes down in 1100 ℃ in 1200 ℃, making test portion, and carry out comparative evaluation after the pickling with the same operation of experiment 1.Its result is as shown in table 3 like that, contrast with successful test portion 1 (in the experiment 1 is test portion 9), be in 1200 ℃ of test portions 2 that are incubated down, the compound ratio of separating out is almost 0, and observe much and separate out separately and tiny B precipitate, crystal particle diameter and iron loss after the stress relieving are the poorest.On the other hand, be in 1100 ℃ of test portions 3 that are incubated down that though not as 1200 ℃ heating material (test portion 2), the ratio of compound precipitate is low to 5%, crystal particle diameter and iron loss are all not good yet.It is as follows that this result can think: at first, at 1200 ℃ of following under the situations of insulation and in addition Mn height to 0.42%, though MnS separates out, but directly carry out hot rolling at the undecomposed state of B, therefore generate independent and tiny B precipitate in course of hot rolling and during stress relieving, grain growing and iron loss worsen significantly.Secondly, can think that the distribution of MnS is thicker at 1100 ℃ down under the situations of insulation, make the number deficiency of the compound nuclear of separating out of BN, therefore a part of B separates out separately and slightly, can not obtain good crystal particle diameter and iron loss.

Table 3

Symbol	The hot rolling Heating temperature	Crystal particle diameter (μ m)	W15/50 (W/kg)	The compound ratio (%) of separating out	Remarks
						1	1200℃→1100℃	54	4.03	25	Example
2	1200℃	19	5.68	0	Comparative example
						3	1100℃	35	4.51	5	Comparative example

(experiment 4)

Secondly, in order to investigate the influence of hot rolled heating cycle, use the Mn of experiment 2 to be 0.42wt%, Ti steel disc as 0.0013wt%, implement the hot rolling heating of following 2 levels: be incubated 60 minutes down or be incubated 60 minutes down in 1100 ℃ in 1200 ℃, making test portions, and carry out comparative evaluation after the pickling with the same operation of experiment 2.Its result is as shown in table 4 like that, contrast with successful test portion 1 (test portion 5 in the experiment 2), be in 1200 ℃ of test portions 2 that are incubated down, though sulfide density is low, but the distribution density height of Ti precipitate, crystal particle diameter and iron loss after the stress relieving are the poorest.On the other hand, in the test portion 3 that is to be incubated under 1100 ℃, though Ti precipitate density is low, sulfide density height, crystal particle diameter and iron loss are all not good yet.It is as follows that this result can think: at first, be under 1200 ℃ of situations about being incubated down, Mn height to 0.42% in addition, though then MnS carry out thickization, but directly carry out hot rolling at the undecomposed state of TiN, therefore, generate independent and tiny Ti precipitate in course of hot rolling or during stress relieving, grain growing and iron loss significantly worsen.Secondly can think that be that the growth of MnS is insufficient in 1100 ℃ of situations about being incubated down, the number of sulfide increases, thereby can not obtain good crystal particle diameter and iron loss.

Table 4

Symbol	The hot rolling Heating temperature	Sulfide density is (individual/mm 2)	Ti precipitate density is (individual/mm 2)	Crystal particle diameter (μ m)	W15/50 (W/kg)	Remarks
							1	1200℃→ 1100℃	2.7×10 5	＜1.0×10 3	53	4.05	Example
2	1200℃	1.8×10 5	5.6×10 3	25	5.44	Comparative example
							3	1100℃	4.8×10 5	＜1.0×10 3	35	4.77	Comparative example

Sum up above content, the present invention has found following proposal: by the optimizing to Mn amount and hot rolled heating cycle MnS preferentially and is best separated out, tiny BN is compound to separate out by making simultaneously, and the two is innoxious simultaneously and improve grain growing and iron loss thereby make MnS and BN.In order to realize this scheme, must the Al amount be reduced.This be because Al with the form of AlN consume N, AlN itself also hinders the cause of grain growing simultaneously.On the other hand, do not adding fully in the manufacture method of Al, because that Al amount Be Controlled gets is extremely low, though then favourable to the generation of BN, a large amount of remaining SiO in the steel ₂The MnO inclusion is accompanied by increasing and extension of Mn amount, and grain growing is worsened.Therefore, the present invention finds the extension that suppresses to be caused by the modification of inclusion and makes the optimum range of the Al that BN preferentially separates out to be 0.01%～0.04%.

In addition, the present invention has also found following proposal: by to the optimizing of separating out temperature of MnS and TiN and the optimizing of hot rolled heating cycle, at first make MnS separate out thickly, secondly make that tiny TiN is compound separates out, make the two precipitate innoxious and improve grain growing and iron loss thus.

In order to realize this scheme, need to improve the Mn amount so that MnS separate out temperature improve and reduce the Al amount with the generation that suppresses AlN, promote separating out of TiN.As Al amount is suppressed extremely low method, can list in the steel-making method, but learn that in this case if the Mn amount is increased, then the inclusion extension makes iron loss worsen conversely with the Si deoxidation.Therefore, the present invention is by being controlled at Al amount 0.01～0.04% fewer scope, can be when keeping the separating out of TiN, and the modification by inclusion improves the Mn amount.And, in this Al weight range, the tiny of the deleterious AlN of grain growing separated out because the residue N of TiN after separating out generates easily, therefore add B and form BN and avoided this problem by trace.

Such technological thought is the opinion that the present invention at first finds, open in the clear 58-117828 communique for example spy, though regulation contains Si:0.1～1.0%, Al: be lower than 0.1%, Mn:0.75～1.5%, N/B are 0.7～1.2 B, but Sol.Al amount or the but regulation not such as hot rolled Heating temperature separating out and realize it for MnS and BN compound, therefore be diverse with technological thought of the present invention, neither analogize the present invention and obtain.In addition, open in the 2000-248344 communique the spy, though regulation Si:1.8% is following, Sol.Al:0.05～0.20%, Mn:0.05～1.5%, but AlN can separate out than BN is preferential on the contrary when surpassing 0.04% at Sol.Al, therefore untenable technological thought of the present invention i.e. " is that nuclear is separated out BN with MnS ".

Secondly, the numerical definiteness reason of composition of the present invention and product is narrated.

Si: be effective element, but when interpolation surpassed 1.5%, hardness raise or magneticflux-density reduces and cost increases, so the upper limit is set at 1.5% for resistance is increased.

Mn: be in order to realize important element of the present invention.Purport of the present invention be " with the sulfide that comprises MnS serves as nuclear BN and/or TiN are separated out ", for this reason, BN and/or TiN separate out temperature before MnS is fully separated out.For make its contain below the Ti:0.0015%, below the N:0.0030% and B/N be the present invention of 0.5～1.5 B, by Mn is made as 0.4% with on reach this purpose.And when adding Mn and surpass 1.5%, not only the reduction of saturation magnetic flux density is remarkable, and γ → α transformation temperature also reduces, and makes the organizational controls of the hot-rolled sheet difficulty that becomes, so the upper limit is set at 1.5%.

Al: the bioelement that is steel-deoxidizing.When Sol.Al is lower than 0.01%, is not remained in the steel and generate SiO by the oxygen of deoxidation ₂The oxide compound of MnO, it combines and extension with the influence of having added the Mn more than 0.4%, thereby hinders grain growing, so the lower limit set of Sol.Al is 0.01%.When Sol.Al surpassed 0.04%, AlN replaced BN and separates out, and made the realization of the present invention difficulty that becomes, and, from guarantee TiN separate out and the demand client of being convenient to applies flexibly the viewpoint of waste material, the upper limit of Sol.Al is set at 0.04%.

Ti: generate TiN grain growing is significantly worsened, but, therefore be difficult to be 0 industrial owing to be the element of unavoidably sneaking into.In the present invention, as by with MnS, Cu ₂Compound separating out such as S and complex sulfide thereof and tolerance that may be innoxious, the upper limit is defined as 0.0015%.When Ti surpassed 0.0015%, the beginning of TiN separated out temperature and uprises, thereby can not control preferentially separating out of MnS.

N: except BN, generate TiN or AlN.For the present invention who contains Sol.Al:0.01～0.04%, if generate AlN then grain growing significantly worsen, therefore need to add the generation that B suppresses AlN.So, measure the B amount that must increase interpolation when high at N, but the B that adds can cause the embrittlement of steel plate superfluously and productivity is worsened, so the upper limit of N is set at 0.0030%.

S:, make to contain more than 0.0010% and just can reach purpose of the present invention for the sulfide of separating out nuclear that generates as BN and/or TiN is necessary.But when surpassing 0.0040%, the amount of separating out of sulfide self increases, and grain growing is hindered, so the upper limit is set at 0.0040%.

B: be in order to suppress the generation of the deleterious AlN of grain growing and the element that must add, for this purpose, adding in B/N is necessary more than 0.5%.Even add with respect to N superfluously, effect also can be saturated, so the upper limit is set at 1.5 in B/N.

Sn, Cu, Ni: produce effect for the nitrogenize or the inhibition of oxidation on stress relieving light plate surface especially for annealing, for the steel of the present invention that contains Sol.Al:0.01～0.04%, because especially easily by nitrogenize, therefore preferred the interpolation.As addition, when being lower than 0.01%, then there is not effect; When interpolation surpasses 0.50%, the then saturated and cost raising of effect, so the scope of addition is set at 0.01%～0.50%.And it is equal that the nitrogenize of Sn, Cu, Ni or oxidation suppress effect, and therefore no matter single or compound interpolation is as long as satisfy above-mentioned addition scope.In addition, also can add among REM, Ca, the Mg a kind with 0.001～0.5% amount, more than 2 kinds.

Especially, Sn is to the raising of magneticflux-density of the present invention effective elements extremely.This is that the Mg amount is enhanced because in the present invention, and therefore γ → α transformation temperature reduces inevitably, and can not promote the grain growing of hot-rolled sheet fully, therefore is necessary this is remedied.As addition,, surpass 0.50% saturated and cost increase of effect if add, so the scope of addition is set at 0.01%～0.50% if being lower than 0.01% does not have effect.In addition, Sn also produces effect to nitrogenize or the oxidation that suppresses stress relieving light plate surface, also wishes to add from this viewpoint.

For separating out as the compound of feature of the present invention, the compound number proportional divider that contains Mn sulfide of separating out of B precipitate is decided to be more than 10%.This observations that is based on the test portion that has independent and tiny B precipitate hardly proposes.

Crystal particle diameter is in order to possess the important factor of stamping-out processibility and magnetic simultaneously.In the steel plate of supplying with stamping-out processing, if particle diameter surpasses then stamping-out processibility deterioration of 30 μ m, so crystal grain crystalline substance is set at below the 30 μ m.For electric product,, therefore be defined as more than the 50 μ m at the crystal particle diameter after 750 ℃ that carry out usually * 2 hours the stress relieving if particle diameter is lower than 50 μ m and then can not satisfies desired iron loss.

As MnS, Cu ₂When S and complex sulfide thereof are too much, then can hinder grain growing.In order to obtain the crystal particle diameter more than the 50 μ m after the stress relieving, its distribution density must be made as 3.0 * 10 ⁵Individual/mm ²Below.Here " distribution density " narrated is that the precipitate of Mn, S or Cu, S or Mn, Cu, S observed, will detect by the test portion that carried out chemical grinding after the mirror ultrafinish by scan-type or transmission type microscope counting is obtained divided by observing visual field area (observed under the situation of a lot of visual fields and be its total area).

The Ti precipitate is by with sulfide being nuclear and compound separating out, although therefore tinyly be lower than 0.1 μ m to the conversion diameter, but still possible innoxious.Obtain after stress relieving in the good steel of crystal particle diameter more than the 50 μ m and iron loss, its equivalent diameter is that the distribution density that is lower than the Ti precipitate of 0.1 μ m is 1.0 * 10 ³Individual/mm ²Below, therefore it is decided to be the upper limit.

Secondly, narrate with regard to qualification reason of creating conditions of the present invention.

The heating of hot rolled slab is in order to make to contain MnS, Cu ₂The sulfide of S and complex sulfide thereof is separated out BN and/or TiN to reach innoxious for nuclear, and two sections continuous circulation is necessary.Brought up in the steel of the present invention more than 0.4% at Mn, in the temperature range more than 1150 ℃, MnS separate out and growth becomes significantly, but then solid solution can take place when surpassing 1250 ℃, so the Heating temperature of leading portion is set at 1150 ℃～1250 ℃.Because the MnS speed of growth is very fast, be just enough more than 5 minutes therefore in the residence time of this temperature range.Secondly, TiN and BN carry out compound the separating out on the MnS is lower than 1150 ℃ so the Heating temperature of back segment is set at being lower than under 1150 ℃ the temperature, and from guaranteeing the viewpoint of rolling property etc., lower limit temperature is set at 1050 ℃.In addition, when the Heating temperature of back segment was lower than 1050 ℃, though separating out of TiN carried out, insufficient with compoundization of sulfide, therefore independent and tiny precipitate increased in course of hot rolling.For the heat-up time of back segment, consider separating out the time of TiN and BN, be set at more than 15 minutes, more preferably more than 30 minutes.

Hot rolled finish to gauge temperature out is the following temperature of γ → α phase transformation, and as far as possible high temperature turn to more than 800 ℃ to obtain high magnetic flux density, but owing to can make this temperature obtain relaxing by the interpolation of Sn, therefore under the situation of adding Sn, consider its demulcent degree, be defined as T 〉=900-1000 * Sn[quality %].

Embodiment 1

Adopt breadboard vacuum melting furnace, make the steel disc that contains C:0.003%, Si:0.55%, Mn:0.12～0.96%, Sol.Al:0.033%, Ti:0.0008%, N:0.0025%, S:0.0032%, B:0.0017%, Sn:0.02～0.09% in quality %.Insulation was 10 minutes after these steel discs were warmed up to 1230 ℃, cooled to 1120 ℃ and carry out hot rolling after being incubated 30 minutes then, and making thickness of slab is 2.5mm, and in addition, the temperature out of finish to gauge is 855 ℃.For this hot-rolled sheet, after being cold-rolled to thickness of slab after the overpickling and being 0.50mm, under 825 ℃, carry out the final annealing in 10 seconds, under 750 ℃, impose 2 hours stress relieving then.For the test portion that obtains like this, measure its crystal particle diameter and iron loss and magneticflux-density, by the transmission electron microscopy precipitate.Its result is as shown in table 5 like that, and in Mn was test portion 7～12 more than 0.4%, the average crystalline particle diameter after the stress relieving was more than the 50 μ m, and has obtained good iron loss, and the number ratio of compound precipitate also is more than 10%.And in the test portion 8,9,11,12 that satisfies 855 〉=900-1000 * Sn, obtained the high magnetic flux density of about 0.02T.

Table 5

Symbol	Mn	Sn	Crystal particle diameter (μ m)	W15/50 (W/kg)	B50 (T)	The compound ratio (%) of separating out	Remarks
								(％)
	1	0.12								0.02	18	5.51	1.71	0	Comparative example
2			0.05	19	5.48	1.74	0	Comparative example
	3								0.09	21	5.47	1.74	0	Comparative example
4			0.26	0.02	29	5.01	1.71	5							Comparative example
	5	0.05							30	4.92	1.74	5	Comparative example
6				0.09	31	4.87	1.74	5						Comparative example
	7	0.43							0.02	55	4.12	1.70	15		Example
8			0.05	57	4.09	1.73	16	Example
	9								0.09	59	4.08	1.73	15	Example
10			0.96	0.02	61	3.96	1.70	35							Example
	11	0.05							64	3.92	1.73	42	Example
12				0.09	65	3.90	1.73	46						Example

Embodiment 2

Adopt breadboard vacuum melting furnace, make the steel disc that contains C:0.003%, Si:1.3%, Mn:0.29～1.08%, Al:0.027%, Ti:0.0013%, N:0.0019%, S:0.0026%, B:0.0024%, Sn:0.07% in quality %.Be cooled to 1090 ℃ immediately after these steel discs are warmed up to 1230 ℃, be incubated 30 minutes, carry out hot rolling then.For this heating, the time that steel disc rests on the temperature more than 1150 ℃ is 15 minutes, and the temperature out of finish to gauge is 840 ℃.In addition, also carried out carrying out the hot rolled test after 60 minutes immediately in heating under the steady temperature of 1230 ℃ or 1090 ℃.For the hot-rolled sheet that obtains like this, after the process pickling and cold-rolling is 0.50mm to thickness of slab, under 850 ℃, carry out the final annealing in 10 seconds, and after carrying out stress relieving in 2 hours under 750 ℃, measure crystal particle diameter and iron loss and magneticflux-density, by the transmission electron microscopy precipitate.Its result is as shown in table 6 like that, at Mn is to be made as more than 0.4% and with hot-rolled temperature in two sections round-robin test portions 10～12 of 1230 → 1090 ℃, average crystalline particle diameter after the stress relieving is more than the 50 μ m, and obtained good iron loss, the number ratio of compound precipitate also is more than 10%.And, all satisfy 840 〉=900-1000 * Sn (=0.07%), obtained higher magneticflux-density.

Table 6

Symbol	The hot rolling Heating temperature	Mn (％)	Crystal particle diameter (μ m)	W15/50 (W/kg)	B50 (T)	The compound ratio (%) of separating out	Remarks
								1	1090℃	0.29	44	4.11	1.73	5	Comparative example
2	0.42	40	4.03	1.72	5	Comparative example
							3	0.71		42	4.00	1.72	5	Comparative example
4	1.08	44	3.96	1.72	5	Comparative example
							5	1230℃		0.29	32	4.66	1.73	0	Comparative example
6	0.42	30	4.53	1.73	0	Comparative example
							7		0.71	32	4.38	1.73	5	Comparative example
8	1.08	33	4.34	1.73	5	Comparative example
							9		1230℃→ 1090℃	0.29	44	4.01	1.72	5	Comparative example
10	0.42	57	3.39	1.72	20	Example
							11	0.71		59	3.35	1.72	30	Example
12	1.08	64	3.21	1.72	50	Example

Embodiment 3

Adopt breadboard vacuum melting furnace, make the steel disc that contains C:0.0038%, Si:0.51%, Mn:0.12～0.84%, Sol.Al:0.025%, Ti:0.0008～0.0024%, N:0.0025%, S:0.0035%, B:0.0016% in quality %.Be cooled to 1120 ℃ immediately after these steel discs are warmed up to 1240 ℃, be incubated and carry out hot rolling after 30 minutes, making thickness of slab is 2.7mm.For this heating, the time that steel disc rests on the temperature more than 1150 ℃ is 22 minutes, and in addition, the temperature out of finish to gauge is 820 ℃.For this hot-rolled sheet, through after pickling and cold-rolling is 0.50mm to thickness of slab, under 825 ℃,, and under 750 ℃, impose 2 hours stress relieving through the final annealing in 10 seconds, the precipitate and the crystal particle diameter of observation steel plate are measured iron loss simultaneously.

Its result is as shown in table 7 like that, is more than 0.4% and Ti is that the sulfide density after the stress relieving is 3.0 * 10 in the test portion 7,8,10,11 below 0.0015% at Mn ⁵Below, the average crystalline particle diameter is more than the 50 μ m, and obtained good iron loss.In these test portions, majority has confirmed to have more diameter to be the spherical sulfide of 0.2～0.3 μ m and to separate out a plurality of Ti precipitates in the periphery of sulfide.On the other hand, hang down in 0.12 or 0.25% test portion 1～6 at Mn, the sulfide density after the stress relieving is higher, and the average crystalline particle diameter is also less, and iron loss is relatively poor.The sulfide diameter of being seen in these test portions is little below 0.1 μ m, and has confirmed to include tiny Ti precipitate in big polysulfide.In addition, though be that Ti surpasses in 0.0015% the test portion 9,12 more than 0.4% at Mn, the sulfide density after the stress relieving is also higher, the average crystalline particle diameter is also less, and iron loss is also poor.In these test portions, fluctuate in the wide region of the diameter of sulfide below 0.05～0.3 μ m, with the complex morphological of Ti precipitate also be varied, or in the periphery of sulfide or in the centre.And in these test portions, the distribution density of Ti precipitate that diameter is lower than 0.1 μ m is all very low, is lower than 1.0 * 10 ³Individual/mm ²

Table 7

Symbol	Mn	Ti	Sulfide density is (individual/mm 2)	Ti precipitate density is (individual/mm 2)	Crystal particle diameter (μ m)	W15/50 (W/kg)	Remarks
								(％)
	1	0.12								0.0006	6.3×10 5	＜1.0×10 3	33	5.11	Comparative example
2			0.0011	7.7×10 5	＜1.0×10 3	23	5.43	Comparative example
	3								0.0016	8.9×10 5	＜1.0×10 3	22	5.77	Comparative example
4			0.25	0.0006	3.5×10 5	＜1.0×10 3	36	4.99							Comparative example
	5	0.0011							4.3×10 5	＜1.0×10 3	25	5.21	Comparative example
6				0.0016	4.9×10 5	＜1.0×10 3	23	5.36						Comparative example
	7	0.48							0.0006	1.3×10 5	＜1.0×10 3	62	4.02		Example
8			0.0011	1.8×10 5	＜1.0×10 3	60	4.06	Example
	9								0.0016	3.6×10 5	＜1.0×10 3	44	4.62	Comparative example
10			0.84	0.0006	1.2×10 5	＜1.0×10 3	69	3.89							Example
	11	0.0011							1.5×10 5	＜1.0×10 3	58	4.10	Example
12				0.0016	3.3×10 5	＜1.0×10 3	46	4.48						Comparative example

Embodiment 4

Adopt breadboard vacuum melting furnace, make the steel disc that contains C:0.0022%, Si:1.2%, Mn:0.31～1.44%, Sol.Al:0.03%, Ti:0.0013%, N:0.0016%, S:0.0031%, B:0.0021%, Sn:0.02% in quality %.Be cooled to 1070 ℃ immediately after these steel discs are warmed up to 1220 ℃, be incubated and carry out hot rolling after 20 minutes.For this heating, the time that steel disc rests on the temperature more than 1150 ℃ is 15 minutes.In addition, also carried out carrying out the hot rolled test after 45 minutes immediately in heating under the steady temperature of 1220 ℃ or 1070 ℃.For the hot-rolled sheet that obtains like this, through after pickling and cold-rolling is 0.50mm to thickness of slab, under 850 ℃,, and under 750 ℃, impose 2 hours stress relieving through the final annealing in 5 seconds, the precipitate and the crystal particle diameter of observation steel plate are measured iron loss simultaneously.Its result is as shown in table 8 like that, is more than 0.4% and the hot rolled Heating temperature is set as in 1220 → 1070 ℃ the test portion 12～15 at Mn, and the sulfide density after the stress relieving is 3.0 * 10 ⁵Below, the average crystalline particle diameter is more than the 50 μ m, and obtained good iron loss.In these test portions, majority has confirmed to have more diameter to be the spherical sulfide of 0.2～0.3 μ m and to separate out a plurality of Ti precipitates in the periphery of sulfide.In other test portion, or the sulfide density height after the stress relieving, or the density height of Ti precipitate, median size is also less, and iron loss is relatively poor.

Table 8

Symbol	The hot rolling Heating temperature	Mn (％)	Sulfide density is (individual/mm 2)	Ti precipitate density is (individual/mm 2)	Crystal particle diameter (μ m)	W15/50 (W/kg)	Remarks
								1	1070℃	0.31	4.0×10 5	＜1.0×10 3	44	4.10	Comparative example
2	0.45	4.1×10 5	＜1.0×10 3	40	4.05	Comparative example
							3	0.68		3.7×10 5	＜1.0×10 3	42	4.07	Comparative example
4	1.03	3.4×10 5	＜1.0×10 3	44	4.04	Comparative example
							5	1.44		3.3×10 5	＜1.0×10 3	41	4.03	Comparative example
6	1220℃	0.31	4.7×10 5	5.5×10 3	32	4.64									Comparative example
							7	0.45	2.7×10 5	5.7×10 3	30	4.51	Comparative example
8		0.68	1.8×10 5	6.1×10 3	32	4.45								Comparative example
							9	1.03	1.3×10 5	7.7×10 3	33	4.36	Comparative example
10		1.44	1.2×10 5	7.2×10 3	34	4.41								Comparative example
							11	1220→ 1070℃	0.31	3.5×10 5	＜1.0×10 3	44	4.02		Comparative example
12	0.45	2.6×10 5	＜1.0×10 3	57	3.71	Example
							13		0.68	2.2×10 5	＜1.0×10 3	59	3.65	Example
14	1.03	1.8×10 5	＜1.0×10 3	64	3.54	Example
							15		1.44	1.4×10 5	＜1.0×10 3	67	3.42	Example

Claims (8)

1. non-oriented electromagnetic steel sheet having is characterized in that: in quality % contain below the Si:1.5%, Mn:0.4～1.5%, solubilized Al:0.01～0.04%, below the Ti:0.0015%, below the N:0.0030%, S:0.0010～0.0040%, B: with B/N count 0.5～1.5 and remainder form by Fe and unavoidable impurities; And separate out with the B precipitate is compound containing counting more than 10% among the sulfide of Mn with the number ratio.

2. non-oriented electromagnetic steel sheet having, it is characterized in that: in quality % contain below the Si:1.5%, Mn:0.4～1.5%, solubilized Al:0.01～0.04%, below the Ti:0.0015%, below the N:0.0030%, S:0.0010～0.0040%, B: with B/N count 0.5～1.5 and remainder by Fe and unavoidable impurities and form, the crystal particle diameter of its light plate is below the 30 μ m, and the crystal particle diameter after 750 ℃ * 2 hours the stress relieving is more than the 50 μ m.

3. non-oriented electromagnetic steel sheet having according to claim 1 and 2 is characterized in that: MnS, Cu ₂The total distribution density of S and complex sulfide thereof is 3.0 * 10 ⁵Individual/mm ²Below.

4. according to any one described non-oriented electromagnetic steel sheet having in the claim 1～3, it is characterized in that: the distribution density of the Ti precipitate of the discontented 0.1 μ m of diameter is 1.0 * 10 ³Individual/mm ²Below.

5. according to any one described non-oriented electromagnetic steel sheet having in the claim 1～4, it is characterized in that: also contain with quality % add up among 0.01～0.50% Sn, Cu, the Ni more than a kind or 2 kinds and/or among 0.001～0.1% REM, Ca, the Mg more than a kind or 2 kinds.

6. the manufacture method of any one described non-oriented electromagnetic steel sheet having in the claim 1～5, it is characterized in that: when then implementing final annealing in system steel, hot rolling, pickling, after cold rolling, heat for the hot rolled slab, stop more than 5 minutes 1150 ℃～1250 ℃ scopes, then more than 1050 ℃ but be lower than 1150 ℃ scope and stop more than 15 minutes, carry out hot rolling then immediately.

7. the manufacture method of any one described non-oriented electromagnetic steel sheet having in the claim 1～6 is characterized in that: when then imposing final annealing at system steel, hot rolling, pickling, after cold rolling, hot rolled finish to gauge temperature out is set at more than 800 ℃.

8. the manufacture method of non-oriented electromagnetic steel sheet having according to claim 6 is characterized in that: for the steel plate that contains Sn, described hot rolled finish to gauge temperature out T (℃) be set at T 〉=900-1000 * Sn (quality %).