Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces Methods of Test for the Determination of Surface Insulation Resistance and Lamination Factor of Electric Sheet and Strip (GB/T 2522-2007); the following changes have been made with respect to GB 2522-2007:
——the standard name is changed to Methods of Test for The Determination of Coating Insulation Resistance and Coating Adhesion of Electrical Strip and Sheet from Methods of Test for the Determination of Surface Insulation Resistance and Lamination Factor of Electric Sheet and Strip;
——the coating insulation resistance test circuit diagram is modified;
——the coating insulation resistance test circuit diagram is modified;
——the test method in which the total area of 10 contacts is 1000mm2 is added;
——the requirements on the total current of 10 contacts are modified;
——the calculation for coefficient of interface resistance is added;
——the repeatability and reproducibility requirements on coating insulation resistance test are added;
——coating adhesion levels are added.
This standard has been redrafted and modified adoption of Magnetic Materials - Part 11: Method of Test for the Determination of Surface Insulation Resistance of Magnetic Sheet and Strip (IEC 60404-11:2012), and it is not equivalent to IEC 60404-11:2012.
This standard is proposed by China Iron and Steel Industry Association.
This standard is under the jurisdiction of the National Technical Committee on Iron and Steel of Standardization Administration of China (SAC/TC 183).
The previous editions of the standard replaced by this standard are as follows:
——GB/T 2522-1981, GB/T 2522-1988, GB/T 2522-2007.
Methods of Test for the Determination of Coating Insulation Resistance and Coating Adhesion of Electrical Strip and Sheet
1 Scope
This standard specifies methods of test for the determination of coating insulation resistance and coating adhesion of electrical strip and sheet.
This standard is applicable to the test for the determination of surface insulation resistance and interface resistance of non-oriented and oriented electrical strip and sheet, as well as the test for the determination of insulation coating adhesion of non-oriented and oriented electrical strip and sheet.
2 Test of Coating Insulation Resistance
2.1 Principle of measurement
The principle of the measurement is based on, and includes, the method originally described by Franklin which characterizes only one coated surface at a time.
The arrangement of the apparatus is shown in Figure 1. Ten metallic contacts of fixed area are applied to one coated surface of the sheet, under specified conditions of voltage and pressure. The effectiveness of the surface insulation is assessed by the measurement of the currents through the 10 contacts.
Keys:
1——d.c. power supply;
2——computer;
3——display;
4——10 contacts;
5——drill;
6——test specimen;
7——insulation coating.
Figure 1 Arrangement of Apparatus for the Measurement of Surface Insulation Resistance
Contacts are fed from a d.c. power supply, as shown in Figure 2, and the voltage between the 5×(1±1%)Ω resistor and the drill is stabilized at 500×(1±0.5%)mV over a current range of 0~1A. The two twist drills perform the function of current return contacts with the metallic substrate of test specimen.
2.2 Test specimen
2.2.1 Each test specimen shall be formed from a single sheet or length of strip. The width and length of the test specimen shall be respectively greater than the width and length of the contact assembly described in 2.3. This measurement is destructive; the test specimen can only be used once.
2.2.2 To obtain a representative result, test specimens shall be taken from the full sheet width. The test specimen surface shall be clean, flat and neat, and be free from any spot and scratch.
2.3 Apparatus
2.3.1 Contact assembly
The test specimen is pressed between a plate and the contact assembly. The contact assembly consists of 10 vertically-mounted metallic rods which move axially against springs in amounting block. These 10 contact rods are normally arranged in two rows. However, for convenience these 10 contacts can be arranged in one row. Each rod shall be provided with a contact button of bronze or other suitable material (for example, stainless steel) and shall be electrically insulated from the mounting frame.
Note 1: articulation of contact buttons improves contact by compensating for minor misalignments.
Each of the 10 contacts shall have a contact area of 64.5×(1±1%)mm2 or 100×(1±1%)mm2, giving a total area for the 10 contacts of 645×(1±1%)mm2 or 1000×(1±1%)mm2, and the recommended total area is 645 mm2.
Note 2: only the total area of 645 mm2 is adopted in international standard. Generally, the testing results of corresponding contacts of two total areas are not comparable.
Electrical contact with the substrate of the test specimen shall be achieved by means of two spring-loaded twist drills of about 3 mm diameter which pierce the insulation coating
2.3.2 Power supply
A d.c. power supply capable of maintaining a stabilized voltage of 500mV across the electrodes at the maximum load current of 1.0A shall be used.
2.3.3 Current measurement
The current flowing through the contact buttons shall be measured with an uncertainty of ± 2% or better. This can be achieved by inserting an ammeter in the supply to the contact buttons, at a point outside the connection to the stabilizing circuit.
The electrical arrangements of the stabilizing circuit and current measurement system are shown in Figure 2.
Keys:
1——Stabilized d.c. power supply;
2——drills;
3——contact;
4——output voltage;
5——feedback voltage;
6——test specimen.
Figure 2 Arrangement of Circuit
2.3.4 Determination of applied force
The total force applied by all of the contacts pressing on the test specimen shall be determined by any suitable means with an uncertainty of ±5 % or better.
2.4 Calibration
The calibration of the equipment should be checked in three ways:
a) The contacts and drills shall be applied to a clean copper sheet at nominal testing pressure. The total current passing through the 10 electrodes shall be 1.0×(1±3%)A. If this is not the case, the contacts shall be checked for cleanliness and the drills checked for sharpness and contact resistance.
b) Carbon paper pressed onto white paper by the contacts at nominal testing pressure shall give a set of even smudges free from signs of force concentration. Pressure measurement sheets that could indicate applied pressure as colour density variations can be used instead of the carbon paper and white paper.
c) Standard resistors of 0.1 Ω, 1 Ω, 10 Ω and 100 Ω connected between the drills and each contact button in turn shall be used to show that the stabilization is adequate and that the required current levels can be achieved.
2.5 Measuring procedure
2.5.1 The test specimen shall be positioned between the baseplate and the 10 contacts and a force of 1290×(1±5%)N for the total area of 645 mm2 or 2000×(1±5%)N for the total area of 1000mm2 shall be gradually applied. This corresponds to a pressure of 2 N/mm2.
2.5.2 The stabilized voltage supply shall be applied to the electrodes and the total current shall be recorded or by computer.
2.5.3 If the insulation quality of a single surface is to be evaluated in the test, 10 readings shall be taken using the 10 contacts on 10 separate representative areas of the sheet or on 10 test specimens.
2.5.4 If the insulation quality of both surfaces is to be jointly evaluated in the test then ten applications of the contacts shall be made to each surface on five separate representative areas or test specimens. The same area of the test specimen shall not be used to test both sides.
2.6 Calculation of coating insulation resistance
2.6.1 Coefficient of surface insulation resistance
The coefficient of surface insulation resistance shall be determined by inserting the 10 values of the current flowing through the 10 electrodes in parallel (either all from one surface or five from each of the two coated surfaces) in Formula (1).
(1)
Where,
C——the coefficient of surface insulation resistance, in ?·mm2/side or ?·cm2/side;
A——the total area of the 10 contacts, in mm2 or cm2;
U——the voltage applied to the contacts and 5 ? resistors, in V;
R——the resistance in series with each contact, equal to 5 ?, in Ω;
IA——the measured total electrode current (10 values), in A;
2.6.2 Coefficient of interface resistance
Value RA represented by coefficient of interface resistance is the resistance of the two surfaces of the product, it is theoretically twice of the coefficient of surface insulation resistance (C).
The coefficient of interface resistance shall be determined by inserting the 10 values of the current flowing through the 10 electrodes in parallel (five from each of the two coated surfaces, 10 values in total) in Formula (2).
(2)
Where,
RA——the coefficient of interface resistance, in ?·mm2/sheet or ?·cm2/sheet;
A——the total area of the 10 contacts, in mm2 or cm2;
U——the voltage applied to the contacts and 5 ? resistors, in V;
R——the resistance in series with each contact, equal to 5 ?, in Ω;
IA——the measured total electrode current (10 values), in A;
2.7 Repeatability and reproducibility
Even when equipment, operation and maintenance, etc. are in good condition, their repeatability and reproducibility are greatly affected by the surface properties of the test specimen when testing coating insulation resistance by Franklin's method. In actual test, it is very difficult evaluate the repeatability and reproducibility of the method.
2.8 Test report
Unless otherwise agreed, the test report shall include:
a) The number of this standard;
b) The identification and status of test specimen and coating;
c) The total area of the contacts of the selected equipment, 645 mm2 or 1000 mm2;
d) Test result: the coefficient of surface insulation resistance or the coefficient of interface resistance.
3 Test Method for Coating Adhesion
3.1 Apparatus
Brass cylinders with smooth surface and in diameter of 10mm, 20mm and 30mm respectively and the tolerance of -0.5 mm~+0.1 mm are used.
3.2 Test specimen
Representative test specimens shall be taken in the direction parallel to the rolling direction, not be less than 40mm from the edge of steel strip (sheet), without damaging test specimen coating. Dimensions of test specimen: 30 mm±0.2 mm in width and 280 mm~320 mm in length. The supplier and the purchaser can negotiate about special requirements, if any.
Foreword i
1 Scope
2 Test of Coating Insulation Resistance
3 Test Method for Coating Adhesion
ICS 77.040.99
H 21
中華人民共和國國家標準
GB/T 2522—2017
代替GB/T 2522—2007
電工鋼帶(片)涂層絕緣電阻和附著性測試方法
Methods of test for the determination of coating insulation resistance and coating adhesion of electrical strip and sheet
(IEC 60404-11：2012，Magnetic materials—Part 11：Method of test for the determination of surface insulation resistance of magnetic sheet and strip，NEQ)
2017-07-12發布 2018-04-01實施
中華人民共和國國家質量監督檢驗檢疫總局
中國國家標準化管理委員會
發布
前言
本標準按照GB/T 1.1—2009給出的規則起草。
本標準代替GB/T 2522—2007《電工鋼片(帶)表面絕緣電阻、涂層附著性測試方法》，與GB/T 2522—2007相比，主要變化如下：
——標準名稱由《電工鋼片(帶)表面絕緣電阻、涂層附著性測試方法》改為《電工鋼帶(片)涂層絕緣電阻和附著性測試方法》；
——修改了涂層絕緣電阻測試電路圖；
——刪除了涂層絕緣電阻測試的方法B；
——增加了10個觸頭總面積為1 000 mm2的測試方法；
——修改了10個觸頭的總電流的規定；
——增加了層間電阻系數的計算；
——增加了涂層絕緣電阻測試重復性和再現性要求；
——增加了涂層附著性級別。
本標準使用重新起草法參考IEC 60404-11：2012《磁性材料 第11部分：測定磁性鋼板帶表面絕緣電阻的測試方法》編制，與IEC 60404-11：2012的一致性程度為非等效。
本標準由中國鋼鐵工業協會提出。
本標準由全國鋼標準化技術委員會(SAC/TC 183)歸口。
本標準起草單位：武漢鋼鐵股份有限公司、寶山鋼鐵股份有限公司、首鋼總公司、冶金工業信息標準研究院。
本標準主要起草人：劉集中、沈杰、向前、石建銳、王玉婕、胡守天、唐靈、龔堅、劉寶石、魏海麗、周星、邱憶。
本標準所代替標準的歷次版本發布情況為：
——GB/T 2522—1981、GB/T 2522—1988、GB/T 2522—2007。
電工鋼帶(片)涂層絕緣電阻和附著性
測試方法
1 范圍
本標準規定了電工鋼帶(片)涂層絕緣電阻和附著性的測試方法。
本標準適用于無取向和取向電工鋼帶(片)表面絕緣電阻和層間電阻的測試，以及無取向和取向電工鋼帶(片)絕緣涂層附著性的測試。
2涂層絕緣電阻的測試
2.1 測量原理
采用只能進行單涂層測量的富蘭克林法。
設備電路示意圖如圖1所示。在規定的電壓和壓強下，將10個固定面積的金屬觸頭壓在鋼板的一個涂層表面上。通過測量流過10個觸頭的電流來評定表面絕緣涂層的效能。
說明：
1——直流電源；
2——計算機；
3——顯示器；
4——10個觸頭；
5——鉆頭；
6——試樣；
7——絕緣涂層。
圖1 表面絕緣涂層電阻測量電路示意圖
觸頭由直流電源供電，如圖2所示，5×(1±1％)Ω電阻和鉆頭間的電壓在電流0～1 A的范圍內穩定在500×(1±0.5％)mV。兩個螺旋鉆頭的作用是與試樣金屬基板接觸構成電流回路。
2.2試樣
2.2.1 每個試樣應由一個樣片或一段樣帶構成。試樣的長度和寬度應分別大于2.3所述的觸頭部件的長度和寬度。測試是破壞性的，試樣只能使用一次。
2.2.2為了得到具有代表性的結果，試樣應從鋼板的整個寬度上剪取。試樣表面應清潔、平整、無斑痕和劃痕。
2.3測試裝置
2.3.1觸頭部件
待測試樣被壓在平板底座和觸頭部件之間，觸頭部件由10根垂直安裝的金屬桿組成，這些金屬桿可壓縮彈簧在固定的單元內軸向移動。這10個觸頭通常排成兩行，為方便使用也可排成一行。每根桿的端部由一個用青銅或其他合適的材料(如不銹鋼)做的觸頭極靴.并與框架絕緣。
注1：萬向連接方式的極靴可通過小范圍補償觸頭的角度偏差，改善電接觸。
10個觸頭中的每一個觸頭的面積選用64.5×(1±1％)mm2或100×(1±1％)mm2，10個觸頭的總面積為645×(1±1％)mm2或1 000×(1±1％)mm2，推薦的觸頭總面積為645 mm2。
注2：國際標準只采用觸頭總面積645 mm2。兩種總面積對應觸頭的檢測結果通常不具有可比性。
通過彈簧加載的直徑大約為3 mm的兩個鉆頭鉆穿試樣的絕緣涂層，使鉆頭與試樣金屬基板形成電接觸。
2.3.2 電源
應使用最大負載電流為1.0 A的直流穩壓電源，確保兩電極間電壓穩定在500 mV。
2.3.3 電流測試
以±2％或更小的測量不確定度的方法測試流過觸頭極靴的電流。這可以在穩壓電源的輸出端與觸頭極靴之間靠近電源一側接入一只電流表。
穩壓電路和電流測試系統電路原理圖如圖2所示。
說明：
1——直流穩壓電源；
2——鉆頭，
3——觸頭；
4——輸出電壓；
5——反饋電壓；
6——試樣。
圖2電路示意圖
2.3.4外加力的測定
應以±5％或更小的測量不確定度的合適的方法測試所有觸頭施加在待測試樣上的合力。
2.4設備確認
設備的確認宜采用以下三種形式：
a)在額定試驗壓力下，把觸頭和鉆頭施加于潔凈的銅板上，流過10個觸頭的總電流應是1.0×(1±3％)A，如果實際情況與之不符，應檢查觸頭的清潔度、鉆頭的銳度和接觸電阻。
b)在額定試驗壓力下，通過觸頭把復寫紙壓在白紙上，這時應出現均勻的壓痕。而沒有力集中的痕跡。可用顏色密度變化顯示施加壓力的力度測量板來代替復寫紙和白紙。
c) 依次把0.1 Ω、1 Ω、10 Ω和100 Ω的標準電阻連接到鉆頭與觸頭極靴之間，示值穩定，并達到所要求的電流水平。
2.5測試步驟
2.5.1 把試樣放在試樣臺和10個觸頭之間，緩慢施加一定的力：對于645 mm2的總面積施加1 290×(1±5％)N的力，對于1 000 mm2的總面積施加2 000×(1±5％)N的力，相當于2 N/mm2壓力。
2.5.2 以穩壓電源對電極供電，并讀取總電流(或由計算機讀取)。
2.5.3如果測試是評價單面的涂層絕緣質量，應使10個觸頭在鋼板的10個具有代表性的不同區域或者10個測試樣上測取10個數據。
2.5.4如果測試是綜合評價雙面涂層的絕緣質量，則應使用10個觸頭在鋼板的每一面選取5個具有代表性的不同區域或者在5個測試試樣上進行測試，在測試試樣的同一個區域不應進行兩面的測試。
2.6涂層絕緣電阻的計算
2.6.1 表面絕緣電阻系數
將10個并聯觸頭10次測量的電流值代入式(1)。計算得出表面絕緣電阻系數(單面涂層10次測量值，或涂層上下表面每個面各5次測量值)。
…………………………(1)
式中：
C——表面絕緣電阻系數，單位為歐姆平方毫米每面(Ω·mm2/面)或歐姆平方厘米每面(Ω·cm2/面)；
A——10個觸頭的總面積，單位為平方毫米(mm2)或平方厘米(cm2)；
U——施加在觸頭和5 Ω電阻上的電壓，單位為伏特(V)；
R——與每個觸頭串聯的電阻，等于5 Ω，單位為歐姆(Ω)；
IA——每次測量的總電流(10個數值)，單位為安培(A)。
2.6.2層間電阻系數
層間電阻系數表示的RA值代表了產品上下兩個表面電阻值，理論上是表面絕緣電阻系數C的2倍。
將10個并聯觸頭10次測量的電流值代入式(2)，計算得出層間電阻系數(涂層面每面5次測量值，兩個面共10次測量值)。
………………………(2)
式中：
RA——層間電阻系數，單位為歐姆平方毫米每片(Ω·mm2/片)或歐姆平方厘米每片(Ω·cm2/片)；
A——10個觸頭的總面積，單位為平方毫米(mm2)或平方厘米(cm2)；
U——施加在觸頭和5 Ω電阻上的電壓，單位為伏特(V)；
R——與每個觸頭串聯的電阻，等于5 Ω，單位為歐姆(Ω)；
IA——每次測量的總電流(10個數值)，單位為安培(A)。
2.7重復性和再現性
即使設備及操作和維護等都處于良好狀態時，用富蘭克林法測試涂層絕緣電阻，其重復性和再現性很大程度上受試樣表面特性的影響。在實際測試中很難評估方法的重復性和再現性。
2.8測試報告
測試報告至少包括以下信息，除非另有約定：
a)本標準編號；
b)試樣和涂層的標識和狀態；
c) 選用設備的觸頭總面積，645 mm2或1 000 mm2；
d)測試結果：表面絕緣電阻系數或層間電阻系數。
3涂層附著性的測試方法
3.1 裝置
裝置是直徑分別為10 mm、20 mm、30 mm，公差為-0.5 mm～+0.1 mm的表面光滑的黃銅圓柱體。
3.2試樣
在離鋼帶(片)邊部不小于40 mm的地方，沿平行于軋制方向剪切具有代表性的試樣，不得損傷試樣涂層。試樣的尺寸：寬度為30 mm±0.2 mm，長度為280 mm～320 mm。如有特殊要求，供需雙方協商確定。
3.3測試
在室溫下，將試樣緊緊圍繞黃銅圓柱體彎曲180°，再將彎曲后的試樣扳直，檢查試樣內表面涂層的剝落情況。一般最先使用20 mm黃銅圓柱體彎曲，如必要再使用10 mm或30 mm黃銅圓柱體彎曲。
3.4評級
如無特殊要求，鋼帶(片)涂層絕緣附著性按表1評級。
表1 涂層附著性評級表
涂層級別 彎曲直徑
10 mm 20 mm 30 mm
A 無脫落 無脫落
B 稍有脫落
C 脫落 稍有脫落 無脫落
D 脫落 無脫落
E 稍有脫落
F 脫落
注：稍有脫落是指試樣彎曲后再將其扳直，目視可見的少量剝落。
3.5測試報告
測試報告至少包括以下信息，除非另有約定：
a)本標準編號；
b)試樣和涂層的標識和狀態；
c)測試結果：涂層級別。
