201122115 t、發明說明： 【發明所屬之技術領域】 本發明是有關於一種滲氮退火程序，特別是指一種用 於製備方向性電磁鋼片之滲氮退火程序。 【先前技術】 由於方向性電磁鋼片在軋延方向具有{11〇}<〇〇1>集合 組織，因此在該方向具錢異之磁通（inducti〇n，B8>1 78T) 及極低之鐵損（iron loss，Wn,5〇<1·55慨§)，此取向性發生 之冶金原理乃取決於最終之高溫退火時的二次再結晶之完 整發生，二次再結晶組織是通過抑制一次再結晶之晶粒成 長，並且有選擇性地使{11〇}<〇〇1>晶粒在二次再結晶時成 獲仵其曰曰粒成長的原動力為該—次再結晶之晶界能 ，且成長過程亦受到AlN、MnS等晶粒抑制劑的影響，而 一般所長成之晶粒尺寸則為數公分不等。 古田用於製備方向性電磁鋼片常使用的製程有兩類：一為 胚製程（鋼胚再熱溫度為>13〇〇。〇 ;另一為低溫鋼胚 ^鋼料熱溫度為蘭y扇。〇。因高溫鋼胚製程中之 :軋^板胚需長時間高溫下加熱才能固m戈Mns等 ==劑，且隨後在熱乾後的冷卻過程中，使得該等晶 需要Π分佈適宜的析出相。在實際製料，則往往 ::::到_，以確使鋼板可達到均溫之狀態，如此 易：：將：加高溫鋼胚製程之能量耗損，並使得板胚表面 在：爐費用增加、爐子壽命減短、板胚内 狀曰日而在後續熱軋時形成橫向裂紋等。 狂 201122115 續力入曰4 鋼胚製程之缺點’低溫鋼製程採用後 =入s曰粒抑制劑的方式，所以初期於鋼胚再加熱時，便 不而要加熱至高溫以完全固溶所有的晶粒抑制劑。又由於 Z鋼胚製程主要是利肖趟作為晶粒抑制劑，其方式為 原子在渗氣退火程序時加入鋼胚中，使得N原子於二 次再結晶退火之低溫期與A1原子結合並形成趣以抑制201122115 t, invention description: TECHNICAL FIELD The present invention relates to a nitriding annealing process, and more particularly to a nitriding annealing process for preparing a directional electromagnetic steel sheet. [Prior Art] Since the directional electromagnetic steel sheet has a {11〇}<〇〇1> assembly structure in the rolling direction, the magnetic flux (inducti〇n, B8> 1 78T) and the pole in this direction are different. Low iron loss (iron loss, Wn, 5〇 <1·55 §), the metallurgical principle of this orientation occurs depending on the complete occurrence of secondary recrystallization during the final high temperature annealing, secondary recrystallization By suppressing the grain growth of one recrystallization, and selectively making the {11〇}<〇〇1> grain in the secondary recrystallization, the motive force for the growth of the grain is the same. The grain boundary energy of crystallization, and the growth process is also affected by grain inhibitors such as AlN and MnS, and the grain size generally grown varies from several centimeters. There are two types of processes commonly used by Gutian for the preparation of directional electromagnetic steel sheets: one is the embryo process (the reheat temperature of the steel embryo is > 13 〇〇. 〇; the other is the low temperature steel blast; the hot temperature of the steel is blue y Fan.〇. Because of the high temperature steel embryo process: the rolling of the sheet embryo needs to be heated for a long time under high temperature to fix the Mns and other agents, and then in the cooling process after the heat drying, the crystals need to be distributed. Appropriate precipitation phase. In actual material production, it is often :::: to _, so that the steel plate can reach the state of uniform temperature, so easy:: will increase the energy consumption of the high temperature steel embryo process, and make the surface of the blast In the following: the increase of furnace cost, the shortening of furnace life, the formation of transverse cracks in the subsequent hot rolling, etc. mad 201122115 Continuing force into the 钢4 steel embryo process defects 'low temperature steel process after adoption = into s曰The method of granule inhibitor, so when the steel embryo is reheated at the beginning, it is not necessary to heat to high temperature to completely dissolve all the crystallite inhibitors. And because the Z steel embryo process is mainly as a grain inhibitor, The way is that the atoms are added to the steel embryo during the gassing annealing process, so that the N Secondary recrystallization at a low temperature of the annealing in combination with the atoms A1 and to inhibit formation of interest
Goss方位以外之晶粒成長的發生，而有助於產出良好磁性 之方向性電磁鋼片。因此，低溫鋼胚製程常採用之滲氮退 火程序例如：於高溫退火隔離劑中加入一可氮化之化學製 劑’經塗覆後，在高溫下進行滲氮退火；在高溫退火的加 熱階段，把氮化氣體加入一可控氣氛當中，以形成一氮化 劑；或於脫碳後，在一氮化氣氛下，以形成一氮化劑其 介質則為分解氨。 ' 然而低溫鋼胚製程亦衍生出其它未解決之相關問題·· ⑴由於方向性電磁鋼片之冶金製程長，且各階段程序之關 聯性高，為避免不可預期之磁性變異，於製程中須嚴格管 控鋼胚中的多種化學成分含量在一極窄的範圍之内[例如： C之含量為400〜500 ppm(重量百萬分率，卿^ miui〇n， ppm)、Si之含量為3.2〜3.3 wt%(重量百分率）、A丨之含量為 270〜 ppm，以及Ti之含量須小於3〇ppm]，當以不符控 制範圍之鋼料行後續製程時，將無法獲得合格的產品（磁 通仏>1.781'及鐵損Wl7/5G<i.55 w/kg)，造成產品的剔退與 損失’且亦會增加製造成本；⑺此外，後續的熱軋退火、 冷乳、脫碳退火、渗氮退火 '氧化鎮塗覆、二次再結晶退 201122115 - 《等程序中的製程參數，亦須被限制在-極小的窗口範圍 中操作，尤其是經滲氮退火程序所得方向性電磁鋼片之半 成品鋼胚的總氮量之目標值須控制在如2〇〇±2〇 ppm(約 的範圍内。由此可知，傳統之低溫鋼胚製程若未能 同時嚴格控制鋼胚之各種成分含量及總兔量目標值，將無 法獲得良好磁性之方向性電磁鋼片。 由上述可知，尋求-更具彈性與操作適性的方向性電 4㈣製程’时效降低於滲氮退火料巾的參數限制、 I品之剔退率以及成本’是目前產業界虽需突破的瓶頸。 【發明内容】 鑒於上述之方向性電磁鋼片製程主要是利用渗氛退火 . f序中所析出之A1N作為晶粒抑制劑，故後續於二次再結 a的過程中’月b否造成{no}，！〉。。”方 大幅併吞其它晶粒’以產出具有良好磁性之方向性= 片，則受到該析出之A1N晶粒抑制劑的控制，而此剔析 • 出的數量、散佈情形、晶體尺寸等，亦受到鋼胚之A1含量 、渗氮後之總氮含量的影響。本案發明人基於上述之冶金 原理’觀察到鋼胚中的AhTi於二次再結晶過程中與W 口以Φ成A1N及ΤιΝ的競爭關係，跳脫傳統須嚴格控 制鋼胚之化學成分含量於一狹窄範圍的思考模式，經過持 1不斷地研究，提出一鋼胚中之成份含量與總氮量之間的 β係式，以於參氮退火程序中調整滲氮量，㈣到一血續 A1、Ti量相關的總氮量之目標值，並成功地發展出一具有 彈性與操作適性的方向性電磁鋼片製程。 201122115 ® & ’本發明之目的’即在提供一種方向性電磁鋼片 >氮1火程序’包含下列步驟：⑷檢測一鋼胚中之、The occurrence of grain growth outside the Goss orientation contributes to the production of good magnetic directional electromagnetic steel sheets. Therefore, the nitriding annealing process is often employed in a low temperature steelmaking process, for example, adding a nitridable chemical to a high temperature annealing separator, after coating, nitriding annealing at a high temperature; in a heating stage of high temperature annealing, The nitriding gas is added to a controlled atmosphere to form a nitriding agent; or after decarburization, under a nitriding atmosphere to form a nitriding agent, the medium is decomposed ammonia. However, the low-temperature steel blank process also has other unresolved related problems. (1) Due to the long metallurgical process of directional electromagnetic steel sheets, and the high degree of correlation between the procedures at each stage, in order to avoid unpredictable magnetic variation, it must be strict in the process. The content of various chemical components in the controlled steel embryo is within a very narrow range [for example: the content of C is 400~500 ppm (weight parts per million, m ^ μ 〇 ,, ppm), and the content of Si is 3.2~ 3.3 wt% (weight percentage), A丨 content is 270~ppm, and Ti content must be less than 3〇ppm]. When the steel is not in the control range, the qualified product will not be obtained (flux)仏>1.781' and iron loss Wl7/5G<i.55 w/kg), causing product rejection and loss' and also increasing manufacturing costs; (7) In addition, subsequent hot rolling annealing, cold milk, decarburization annealing Nitriding annealing 'oxidized town coating, secondary recrystallization back 201122115 - "Process parameters in the process, must also be limited to operate in a very small window range, especially the directional electromagnetic steel obtained by the nitriding annealing process The total amount of nitrogen in the semi-finished steel embryo The value shall be controlled within a range of, for example, 2〇〇±2〇ppm (approximately). It can be seen that the conventional low-temperature steel embryo process cannot be obtained if the various components of the steel embryo and the total rabbit target value are not strictly controlled at the same time. Good magnetic directional electromagnetic steel sheet. From the above, it can be seen that the directionality of the more flexible and operationally adaptable electric 4 (four) process aging is reduced by the parameter limit of the nitriding annealed towel, the rejection rate of the product I and the cost 'is At present, the industry needs to break through the bottleneck. [Invention] In view of the above-mentioned directional electromagnetic steel sheet process, the A1N precipitated in the f-sequence is mainly used as a grain inhibitor, so the subsequent re-association In the process of 'Month b does not cause {no},!>. "Partially swallow other grains" to produce a good magnetic directionality = sheet, subject to the control of the precipitated A1N grain inhibitor, and The number, distribution, crystal size, etc. of this analysis are also affected by the A1 content of the steel embryo and the total nitrogen content after nitriding. The inventor of the present invention observed the AhTi in the steel embryo based on the above metallurgical principle. Secondary reconnection In the process, the competition relationship with W is Φ into A1N and ΤιΝ, and the traditional mode of strictly controlling the chemical composition of the steel embryo in a narrow range is skipped. After continuous research, the content of components in a steel embryo is proposed. The β-type between the total nitrogen and the total nitrogen, in order to adjust the nitriding amount in the nitrogen annealing process, (4) to the target value of the total nitrogen amount related to the A1 and Ti amount, and successfully develop a flexible Operational directional electromagnetic steel sheet process 201122115 ® & 'The purpose of the invention is to provide a directional electromagnetic steel sheet> nitrogen 1 fire program' includes the following steps: (4) detecting a steel embryo,
Ti的含量；⑻將該鋼胚中之A1、Ti的含量代人—由下式⑴ 所示之關係式，以得到—總氮量目標值： (WA1/1.93)/[WN -(WTi/3.42)] = 0.45-1.70 (I) 於式⑴中’ WAI表示該鋼胚中之Αι的含量，u示該鋼 中 丨的3量，及Wn表示總氮量目標值，而Wa|、wTj 及n則應致以重量百分率…叫或重量百萬分率⑽爪)表 示乂及⑷依口亥步驟（b)所得之總氮量目標值進行一渗氣退籲 火，以製得一方向性電磁鋼片之半成品。 本發明方向性電磁鋼片之渗氮退火程序的功效在於： 提ί、鋼胚中之A卜Τι含量與總氮量目標值的關係式依 該關係式可知總氮量目標值’進而可彈性地調整於渗氣退. 火程序中所需的滲氣量，不僅減少煉鋼時因化學成分含量 之範圍限制所造成的剔退損失’更提昇了產品之合格率與 良率，且大幅降低生產成本。 ^ 【實施方式】 有關本發明之前述及其他技術内容、特點與功效，在 以下將進-步於實施方式與其等之實施例的詳細說明中， 將可清楚的呈現。 本發明經實驗將一系列具有不同的AhTi含量（Wm、 WTi)之方向性電磁鋼片先設定不同的總氣量目標值二 no、170、200、250ppm)以調整滲氮退火程序中的滲氮量 ’經過滲氮處理後，將WA1、WTi、WN之值代入公式： 6 201122115 (WA|/1_93)/[WN -(WTi/3.42)]中計算’經分析其數據結果而得 知當上述之公式的計算值介於〇 45至1 7〇之間所對應之樣 本點具有鐵損值（Wwm)為1.55 W/kg以下之產品合格所需 的磁性’此結果亦可由以下所提之實施例及比較例得到證 實。故本發明方向性電磁鋼片之滲氮退火程序將上述公式 值設定於0.45至1.70之間[即關係式⑴;|。The content of Ti; (8) The content of A1 and Ti in the steel embryo is substituted - the relationship shown by the following formula (1) is obtained to obtain the total nitrogen content target value: (WA1/1.93) / [WN - (WTi / 3.42)] = 0.45-1.70 (I) In the formula (1), 'WAI denotes the content of Αι in the steel, u denotes the amount of bismuth in the steel, and Wn denotes the total nitrogen target value, and Wa|, wTj And n should be expressed in terms of weight percentage...called or weight parts per million (10) claws) and (4) Yikouhai step (b) of the total nitrogen amount target value for a gassing retraction fire to obtain a direction Semi-finished products of electromagnetic steel sheets. The effect of the nitriding annealing procedure of the directional electromagnetic steel sheet of the present invention is as follows: The relationship between the A Τ Τι content in the steel embryo and the target value of the total nitrogen amount can be known as the target value of the total nitrogen amount in the relationship Adjusted to the gas infiltration and the amount of gas infiltration required in the fire program, not only reduces the loss of the chemical composition due to the limitation of the range of steel content, but also improves the yield and yield of the product, and greatly reduces production. cost. The above and other technical contents, features and effects of the present invention will be apparent from the following detailed description of embodiments and embodiments thereof. The invention experimentally sets a series of directional electromagnetic steel sheets with different AhTi contents (Wm, WTi) to set different total gas volume target values of two no, 170, 200, 250 ppm) to adjust the nitriding in the nitriding annealing process. After the nitriding treatment, the values of WA1, WTi and WN are substituted into the formula: 6 201122115 (WA|/1_93)/[WN -(WTi/3.42)] is calculated as 'the data is analyzed and the above is known The calculated value of the formula is between 〇45 and 17 所, and the sample point with the iron loss value (Wwm) of 1.55 W/kg or less is required for the qualification of the product. This result can also be implemented by the following Examples and comparative examples were confirmed. Therefore, the nitriding annealing procedure of the directional electromagnetic steel sheet of the present invention sets the above formula value between 0.45 and 1.70 [i.e., relation (1);
本發明經實驗亦發現，當使用之鋼胚中的A1含量（Wai) 於200ppm時，經滲氮退火後的ΑιΝ析出量會不足，無法 有效抑制G〇SS方位以外之晶粒成長，而若高於 400ppm時，則易因析出之A1N量過高而阻礙後續於二次再 結晶中G〇ss方位之晶粒成長的速度；且 結合N原子，所形成的窗析出量亦會增加，而影響了 A1N之析出量與其做為抑制劑的效果。故較佳地，本發明建 議採行之鋼胚的A1含量(D是介於200〜400 ppm，且Ti 含量(WTi)是介於0〜100 ppm’即可運用關係式⑴之總氮量 目標值⑷的計算以調整出—適合的滲氮退火程序之參數 ’而不需如傳統製程要同時嚴格管控c、si、ai、Ti等化學 成分之組成在一極窄的範圍之内。 步說明，但應瞭解的 不應被解釋為本發明 本發明將就以下實施例來作進一 是’該等實施例僅為例示說明之用，而 實施之限制。 【鋼片鐵損值及磁通測試方法] 下列實施例或比較例中用 以測試方向性電磁鋼片之鐵 7 201122115 損值（wn/5〇)及磁通（Bs)特性之儀器，為使用符合jis匸255〇 (量測方式）、Jis c 2553(方向性電磁鋼片規格）及JIS c 2556 (量測設備）等標準規範之磁性量測儀（購自於Brockhaus Messtechnik 公司）。 <實施例1 > 實施例1為取一高石夕鋼胚（〇 〇5C_3卻）進行低溫鋼胚製 程，經檢測鋼胚的A卜丁i含量（WA|=2〇8ppm、WT =4〇ppm) 之後’將所传之WAI、wTi之值代人本發明所提之關係式⑴ 中並》又疋5亥關係式⑴之值等於〇 45 ’可計算得到一相對 應的總氮量目標值(wN=250ppm)，接著依該Wn之值調整需 施加之滲氮量以進行_滲氮退火程序，並製得—方向性電 磁鋼片之半成品。 <實施例2〜15 > 實施例2〜15是以與實施例1相同的程序步驟以製備方 向性電磁鋼片之半成品，不同之處在於：採用之鋼胚所含 的A卜Ti含量（Wai、WTi)、關係式⑴之設定值以及將其 等代入該關係式⑴經計算所得到相對應的總氮量目標值 (WN)，包括實施例丨之參數值皆列於下表丨中。 <比較例1〜11 > 比較例1〜11是以與實施例1相同的程序步驟以製備方 向性電磁鋼片之半成品’不同之處在於：採用之鋼胚所含 的Al、Ti含量（Wa丨、WTi)，以及將Wa丨、〜代人關係式⑴ 之設定值不介於0.45〜’各比較例之參數值亦列於下表i 中〇 201122115 表1 ·The present inventors have also found that when the A1 content (Wai) in the steel embryo used is 200 ppm, the amount of ΑιΝ precipitated after nitriding annealing is insufficient, and the grain growth other than the G〇SS orientation cannot be effectively suppressed. When it is higher than 400 ppm, the amount of precipitated A1N is too high to hinder the growth of the grain in the G〇ss orientation in the secondary recrystallization; and in combination with the N atom, the amount of window formation is also increased, and It affects the amount of precipitation of A1N and its effect as an inhibitor. Therefore, preferably, the A1 content of the steel embryo recommended by the present invention (D is between 200 and 400 ppm, and the Ti content (WTi) is between 0 and 100 ppm', the total nitrogen amount of the relationship (1) can be used. The calculation of the target value (4) is to adjust the parameters of the appropriate nitriding annealing procedure without the need to strictly control the composition of chemical components such as c, si, ai, Ti, etc. within a very narrow range as in the conventional process. It is to be understood that the invention is not to be construed as being construed as the invention. The invention is to be construed as being limited to the following examples. Test method] The instrument used to test the directional magnetic steel sheet 7 201122115 loss value (wn/5〇) and magnetic flux (Bs) characteristics in the following examples or comparative examples is used in accordance with jis匸255〇 (measurement) Method), a magnetic measuring instrument of standard specifications such as Jis c 2553 (directional electromagnetic steel sheet specification) and JIS c 2556 (measurement equipment) (purchased from Brockhaus Messtechnik Co., Ltd.) <Example 1 > Example 1 In order to take a high-stone steel embryo (〇〇5C_3), the low temperature steel embryo process, After detecting the A-butadiene content of the steel embryo (WA|=2〇8ppm, WT=4〇ppm), the value of WAI and wTi transmitted will be substituted in the relationship (1) of the present invention and 疋5 The value of the relationship (1) is equal to 〇45', and a corresponding total nitrogen target value (wN=250ppm) can be calculated. Then, the nitriding amount to be applied is adjusted according to the value of Wn to perform the nitriding annealing process. A semi-finished product of a directional electromagnetic steel sheet. <Examples 2 to 15> Examples 2 to 15 are the same procedure as in Example 1 to prepare a semi-finished product of a directional electromagnetic steel sheet, except that: The A-Ti content (Wai, WTi) contained in the steel embryo, the set value of the relational expression (1), and the corresponding total nitrogen amount target value (WN) obtained by substituting the relationship into the relation (1), including the examples The parameter values of 丨 are listed in the following table. <Comparative Examples 1 to 11 > Comparative Examples 1 to 11 are the same procedure as in Example 1 to prepare a semi-finished product of directional electromagnetic steel sheets. : The content of Al and Ti contained in the steel embryo used (Wa丨, WTi), and the relationship between Wa丨 and ~ generation relationship (1) Value is not interposed 0.45~ 'each parameter value of Comparative Example are also shown in the following table i 201 122 115 Table 1.2 billion
WAi (ppm) WTi (ppm) 關係式(I)之設定值 WN(ppm) VV17/5〇(W/Kg) Bs (T) 實施例1 208 40 0.45 250 1.26 1.86 實施例2 208 95 0.53 230 1.34 1.83 實施例3 263 28 0.58 242 1.28 1.85 實施例4 208 40 0.68 170 1.24 1.84 實施例5 311 90 0.69 260 1.27 1.88 實施例6 263 28 0.71 199 1.26 1.85 實施例7 390 40 0.85 250 1.30 1.85 實施例8 311 40 0.86 200 1.30 1.83 實施例9 263 28 0.87 164 1.17 1.87 實施例10 208 40 0.91 130 1.42 1.84 實施例11 311 40 1.02 170 1.34 1.82 實施例12 390 40 1.07 200 1.15 1.89 實施例13 263 28 1.28 115 1.13 1.89 實施例14 390 40 1.28 170 1.41 1.81 實施例15 263 24 1.70 87 1.26 1.83 比較例1 29 40 0.06 250 1.86 1.67 比較例2 29 40 0.08 200 1.84 1.67 比較例3 29 95 0.11 170 1.83 1.67 比較例4 29 40 0.13 130 1.85 1.67 比較例5 90 90 0.21 250 1.83 1.67 比較例6 90 40 0.25 200 1.82 1.67 比較例7 90 40 0.29 170 1.84 1.67 比較例8 90 40 0.39 130 2.00 1.66 比較例9 311 95 1.75 120 2.40 1.57 比較例10 390 40 1.87 120 2.51 1.57 比較例11 263 28 2.01 76 2.15 1.61 [鋼片鐵損值及磁通測試結果】 由上表1之測試結果可知，本發明依不同的鋼胚之A1 、Ti含量以關係式（I)調整滲氮退火程序之滲氮量參數，由 實施例1〜15所得之半成品經完成後續之低溫鋼胚製程，可 獲得鐵損W17/5〇Sl.55W/kg且磁通BC1.78T以上之具有優良 201122115 磁性之方向性電磁鋼片產品。當關係式（i)之設定值低於 - 〇_45(比較例1〜8)或高於丨.7(比較例9〜11)時，便難以獲得具 有良好磁性之產品。 综上所述’本發明方向性電磁鋼片之滲氮退火程序， 所提出之關係式（I)可以較傳統製程更具彈性地調整滲氮退 火程序中所需之滲氮量，並大幅地降低了製程鋼胚因化學 成分含量及總氮量目標值之窄範圍限制所造成的剔退率， 明顯改進了方向性電磁鋼片之製備方法，以突破本領域之 產業的技術瓶頸並大為降低生產成本。 · 惟以上所述者’僅為本發明之較佳實施例而已，當不 忐以此限定本發明實施之範圍，即大凡依本發明申請專利 範圍及發明說明内容所作之簡單的等效變化與修飾，皆仍 屬本發明專利涵蓋之範圍内。 · 【圖式簡單說明】無 10 201122115 【主要元件符號說明】無WAi (ppm) WTi (ppm) Set value of relation (I) WN (ppm) VV17/5 〇 (W/Kg) Bs (T) Example 1 208 40 0.45 250 1.26 1.86 Example 2 208 95 0.53 230 1.34 1.83 Example 3 263 28 0.58 242 1.28 1.85 Example 4 208 40 0.68 170 1.24 1.84 Example 5 311 90 0.69 260 1.27 1.88 Example 6 263 28 0.71 199 1.26 1.85 Example 7 390 40 0.85 250 1.30 1.85 Example 8 311 40 0.86 200 1.30 1.83 Example 9 263 28 0.87 164 1.17 1.87 Example 10 208 40 0.91 130 1.42 1.84 Example 11 311 40 1.02 170 1.34 1.82 Example 12 390 40 1.07 200 1.15 1.89 Example 13 263 28 1.28 115 1.13 1.89 Example 14 390 40 1.28 170 1.41 1.81 Example 15 263 24 1.70 87 1.26 1.83 Comparative Example 1 29 40 0.06 250 1.86 1.67 Comparative Example 2 29 40 0.08 200 1.84 1.67 Comparative Example 3 29 95 0.11 170 1.83 1.67 Comparative Example 4 29 40 0.13 130 1.85 1.67 Comparative Example 5 90 90 0.21 250 1.83 1.67 Comparative Example 6 90 40 0.25 200 1.82 1.67 Comparative Example 7 90 40 0.29 170 1.84 1.67 Comparative Example 8 90 40 0.39 130 2.00 1.66 Comparative Example 9 311 95 1.75 120 2.40 1.57 Comparison Example 10 39 0 40 1.87 120 2.51 1.57 Comparative Example 11 263 28 2.01 76 2.15 1.61 [Steel sheet iron loss value and magnetic flux test result] From the test results in Table 1 above, the present invention relates to the A1 and Ti contents of different steel embryos. Formula (I) adjusts the nitriding amount parameter of the nitriding annealing program, and the semi-finished product obtained in Examples 1 to 15 is subjected to the subsequent low-temperature steel embryo process to obtain iron loss W17/5〇Sl.55W/kg and magnetic flux BC1 .78T or more with excellent 201122115 magnetic directional electromagnetic steel sheet products. When the set value of the relation (i) is lower than - 〇 45 (Comparative Examples 1 to 8) or higher than 丨. 7 (Comparative Examples 9 to 11), it is difficult to obtain a product having good magnetic properties. In summary, the nitriding annealing process of the directional electromagnetic steel sheet of the present invention, the relationship (I) proposed can adjust the nitriding amount required in the nitriding annealing process more flexibly than the conventional process, and greatly The rejection rate caused by the narrow range limitation of the chemical composition content and the total nitrogen content of the process steel is reduced, and the preparation method of the directional electromagnetic steel sheet is obviously improved, so as to break through the technical bottleneck of the industry in the field and greatly reduce manufacturing cost. The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, that is, the simple equivalent changes made by the scope of the invention and the description of the invention. Modifications are still within the scope of the invention. · [Simple diagram description] None 10 201122115 [Explanation of main component symbols] None