火花發(fā)射光譜法測(cè)定中低合金鋼不確定度評(píng)定剖析

1、平頂山市質(zhì)量技術(shù)監(jiān)督檢驗(yàn)測(cè)試中心火花發(fā)射光譜法測(cè)定中低合金鋼中碳、硅、錳、硫、磷測(cè)量結(jié)果不確定度評(píng)定1目的測(cè)量結(jié)果受儀器校正、設(shè)備穩(wěn)定、環(huán)境變化及人員等因素影響，因此有必要對(duì)測(cè)量結(jié)果 進(jìn)行不確定度評(píng)估，以讓客戶了解測(cè)量結(jié)果是否符合特定需求，確認(rèn)測(cè)量數(shù)據(jù)之可信賴及真實(shí)的程度。2范圍適用于測(cè)量C、Si、Mn、S、P不確定度的評(píng)定。3參考資料3.1 GB/T4336-2002碳素鋼和中低合金鋼的光電發(fā)射光譜分析法3.2 JJF1059-1999測(cè)量不確定度評(píng)定與表示3.3 CSM01010105-2006火花源發(fā)射光譜法測(cè)定低合金鋼測(cè)量結(jié)果不確定度的評(píng)定規(guī)范 4名詞解釋4.1標(biāo)準(zhǔn)不確定度以標(biāo)準(zhǔn)偏差表

2、示的測(cè)量不確定度。4.2擴(kuò)展不確定度確定測(cè)量結(jié)果區(qū)間的量，合理賦予被測(cè)量之值分布的大部分可望含于此區(qū)間。 5測(cè)試方法5.1依據(jù)GB/T4336-2002對(duì)中低合金鋼標(biāo)樣進(jìn)行測(cè)試。5.2環(huán)境條件：實(shí)驗(yàn)室正常環(huán)境（23芳C, 40-80%RH）5.3使用光譜儀測(cè)量合金標(biāo)準(zhǔn)樣，以評(píng)估光譜分析儀之測(cè)量不確定度。6建立數(shù)學(xué)模型根據(jù)測(cè)量原理及不確定度的來源，建立此測(cè)量不確定度評(píng)估所需的數(shù)學(xué)模型：Wm=C其中Wm是被測(cè)樣品各元素化學(xué)成份值，C是儀器顯示各元素化學(xué)成份平均值，Ii是測(cè) 量各標(biāo)準(zhǔn)物質(zhì)元素的光譜強(qiáng)度，G是相應(yīng)的元素含量；li與相應(yīng)元素含量Ci由最小二乘法回歸 得線性函數(shù)：l=a+bc 。7不確定度

3、之誤差源與分析火花源發(fā)射光譜法測(cè)定元素含量不確定度的來源于以下分量：a）測(cè)量結(jié)果的重復(fù)性；b）標(biāo)準(zhǔn)物質(zhì)標(biāo)準(zhǔn)值的不確定度；c）工作曲線的變動(dòng)性；d）高低標(biāo)校正產(chǎn)生的變動(dòng)性；e）被測(cè)樣品基體不一致引起的不確定度。根據(jù)不確定度來源，且各分量相互獨(dú)立，因此得到：2 2 2 2 2 2 Urel (C) Urei (C)aUrel (C)b Urel (C)c Urel (C) d Urel (C)eUrel (C)a -測(cè)量結(jié)果的重復(fù)性引入的相對(duì)標(biāo)準(zhǔn)不確定度;Urei (C)b-標(biāo)準(zhǔn)物質(zhì)標(biāo)準(zhǔn)值引入的相對(duì)標(biāo)準(zhǔn)不確定度;Urei (C)c-工作曲線變動(dòng)引入的相對(duì)標(biāo)準(zhǔn)不確定度；Urei (C)d -標(biāo)準(zhǔn)化校

4、正引入的相對(duì)標(biāo)準(zhǔn)不確定度；Urei (C)e-被測(cè)樣品基體不一致引入的相對(duì)標(biāo)準(zhǔn)不確定度。8不確定度分量的計(jì)算8.1測(cè)量結(jié)果重復(fù)性分量表1各元素的測(cè)量次數(shù)及測(cè)量結(jié)果名稱123456平均 值標(biāo)準(zhǔn)偏 差標(biāo)準(zhǔn)不確 定度C/%0.1700.1730.1750.1770.1740.1710.17330.002580.0011Si/%0.2140.2160.2150.2170.2140.2150.21520.00120.0005Mn/%0.9260.9210.9270.9240.9250.9230.92430.00220.0009S/%0.0140.0140.0130.0120.0160.0150.0140

5、0.00140.0006P/%0.0370.0340.0330.0350.0360.0340.03480.00150.0006Urei(C)a =0.0011/0.1733=0.0063Urei(Si)a =0.0005/0.2152=0.0023Urei( Mn)a =0.0009/0.9243=0.0010Urei (S)a =0.0006/0.0140=0.0428Urei(P)a =0.0006/0.0348=0.01728.2標(biāo)準(zhǔn)樣品的不確定度分量表2標(biāo)準(zhǔn)樣品定值參數(shù)標(biāo)樣編號(hào)=1=元糸標(biāo)準(zhǔn)值/%標(biāo)準(zhǔn)偏差/%測(cè)量次數(shù)標(biāo)準(zhǔn)不確定度/%相對(duì)標(biāo)準(zhǔn) 不確定度GBW01666C0.1620.00

6、390.00100.0062Si0.1910.00490.00130.0068Mn0.6260.00490.00130.0021S0.00960.000290.00010.0104P0.0440.00290.00070.0159GBW01667C0.1370.00390.00100.0073Si0.1050.00490.00130.0124Mn3.740.0490.01330.0036S0.0570.00390.00100.0175P0.0580.00290.00070.0121GBW01668C0.2270.00390.00100.0044Si0.3240.00490.00130.0040M

7、n0.7710.00690.00200.0026S0.0210.00290.00070.0333P0.0380.00290.00070.0184GBW01669C0.0610.00290.00070.0115Si0.1040.00390.00100.0096Mn2.710.0290.00670.0025S0.0200.00190.00030.0150P0.0490.00390.00100.0204GBW01670C0.1930.00290.00070.0036Si0.2420.00490.00130.0054Mn1.030.0190.00330.0032S0.0270.00190.00030.

8、0111P0.0300.00290.00070.0233各標(biāo)準(zhǔn)樣品的標(biāo)準(zhǔn)不確定度（和相對(duì)不確定度）各不相同，它們對(duì)被測(cè)量的影響可用相 對(duì)不確定度的均方根來表示：Urei（c）_。.。6廠。.。7廠。.。04廠。.。估。.。362 = 0.0070Urel(Si)b0.00682 0.01242 0.00402 O.OO962 0.00542二 0.0082第9頁 共7頁Urei(Mn)b002l2 0.00362 0.00262 0.00252 0.003j 0.0028U rel ( S) bO.。1042O.。1752。03332.1502OM 0.0193Uregr000120.：840

9、.02042毀空 “01848.3工作曲線變動(dòng)產(chǎn)生的分量表3工作曲線測(cè)量參數(shù)標(biāo)樣編號(hào)=1=元糸標(biāo)準(zhǔn)值/%光強(qiáng)度比，lili-(a+bci)2(li-(a+bci)GBW01666C0.1621932, 1933, 19251, 2, -61, 4, 36Si0.1919850, 9865, 9841-2, 13, -114, 169, 121Mn0.62615895, 15897, 15890-1, 1, -61, 1, 36S0.00961112, 1147, 1106-9, 26, -1581, 676, 225P0.0443684, 3676, 3697-2, -10, 114, 100

10、, 121GBW01667C0.1371717, 1720,1730-1, 2, 121, 4, 144Si0.1058246, 8231, 82378, -7, -164, 49, 1Mn3.7475054, 75063, 750384, 13, -1216, 169, 144S0.0573889, 3876, 38972, -9, 104, 81, 100P0.0584674, 4689, 4663-1, 14, -121, 196, 144GBW01668C0.2272485, 2487, 2492-1, 1, 61, 1, 36Si0.32412349, 12352, 123382,

11、5, -94, 25, 81Mn0.77118648, 18661, 18657-3, 10, 69, 100, 36S0.0211787, 1799, 17731, 13, -71, 169, 49P0.0383264, 3279, 32511, 16, -121, 256, 144GBW01669C0.0611069, 1073, 10631, 5, -51, 25, 25Si0.1048218, 8224, 8215-1, 5, -41, 25, 16Mn2.7155486, 55467, 554892, -17, 54, 289, 25S0.0201729, 1738, 17171,

12、10, -111, 100, 121P0.0494038, 4055, 4026-1, 16, -131, 256, 169GBW01670C0.1932195, 2196, 2192-2, -1, 54, 1, 25Si0.24210813, 10800, 108165, -8, 825, 64, 64Mn1.0323549, 23538, 23621-21, -32, 51441, 1024, 2601S0.0272142, 2132,21396, -4, 336, 16, 9P0.0302693,2701,2697-5, 3, -125, 9, 1根據(jù)測(cè)量數(shù)據(jù)，各元素工作曲線的回歸方程分

13、別為：C 式：Ii =548 8540Ci、r =0.99996, Si 式：li =6268 18762Ci、r =0.99997 Mn 式：li =4005 18996Ci、r =0.99992, S 式：li = 561 58352Ci、r =0.99993 P 式:IF57 970 6C6 r =0.99989.以C元素為例計(jì)算，被測(cè)量C的標(biāo)準(zhǔn)不確定度為：式中:、(Ii -(a bc)n_2ug ；R(C-C)2n、(C -c)2i丄nn = 5X 3=15,從測(cè)量數(shù)據(jù)可得 a (h - (a bq )2 =309,i A二309 =4.87515-2=0.156,n2(C -C) =

14、0.0158, c =0.1733%i 4(c - C)2 = (0.1733-0.156=0.0003,P=6 X 2=12由此，u(c)=4.87511 O.O。038540 12 15 0.0158= 0.00023u冋(C)c =0.00023/0.1733 = 0.0013同理可計(jì)算Urel(Si)c =0.00016/0.2152 =0.0007urel(M n)c =0.0005/0.9243=0.0005urel (S)c =0.0001/0.0140 = 0.0071Urel(P)c =0.0001/0.0348 = 0.00298.4標(biāo)準(zhǔn)化校正變動(dòng)產(chǎn)生的分量本方法采用GBW

15、01666和GBW01670進(jìn)行標(biāo)準(zhǔn)化。它們校正時(shí)產(chǎn)生的變動(dòng)性可引用繪 制工作曲線時(shí)該兩點(diǎn)的測(cè)量數(shù)據(jù)相對(duì)不確定度均方根表示。兒糸標(biāo)準(zhǔn)偏差標(biāo)準(zhǔn)不確定度相對(duì)標(biāo)準(zhǔn)不確定度GBW01666GBW01670GBW01666GBW01670GBW01666GBW01670C4.35892.08172.51661.20190.00130.00055Si12.12448.50497.00004.91030.000710.00045Mn3.605645.08142.081726.02780.000130.0011表4標(biāo)準(zhǔn)化測(cè)定參數(shù)S22.14355.131612.78462.96270.01140.0014P1

16、0.59874.0006.11922.30940.00170.00086Urel (C)d= 0.00102 20.00130.00055彳 2urel (Si)d0.000712-0.000452=0.0006Urel ( S) dUrei(M n)d0.00013 0.001122= 0.00080.01142 0.00142= 0.0081Urei(P)dJ.00172 0.0008匚0.0。138.5基體不一致產(chǎn)生的分量設(shè)樣品和標(biāo)準(zhǔn)物質(zhì)的鐵量相差為1%,按均勻分布，鐵量差異的標(biāo)準(zhǔn)不確定度urel (Fe) =1/ . 3 =0.58%。假定鐵的平均濃度為95%，urel (C)e =

17、Urel (Si)e = Urel (Mn)e = urel (S)e = Urel (P)e = 0.58/95=0.0061.8.6其他影響因素由于儀器光譜強(qiáng)度的讀數(shù)數(shù)以千計(jì)、萬計(jì)，光強(qiáng)讀數(shù)的變動(dòng)在十位數(shù)變化，因此儀器顯 示值分辨力的標(biāo)準(zhǔn)不確定度可以忽略不計(jì)。9合成標(biāo)準(zhǔn)不確定度評(píng)定各不確定度分量不相關(guān)，以各分量的相對(duì)不確定度的方和根計(jì)算合成相對(duì)不確定度:； 2 2 2 2 2Urel (C ) = Urel (C )aurel (C )burel (C)curel (C )durel (C )e0.00630.00700. 0 0 1 3 2 0. 0 00.0113 0061urel(S

18、i)二 0.002320.008220.000720.00062 0.00612 =0.0105urel(Mn)二 0.00102 0.00282 0.000520.00082 0.00612 =0.0068 urel(S)h：；0.04282 0.01932 0.00712 0.00812 0.00612 =0.0486Urel(P)=&0.01722 0.01842 0.00292 0.00132 0.00612 =0.0261%(Wc) =0.1733宓 0.0113=0.0020%Uc(Ws) =0.2152%x 0.0105=0.0022% uc (wMn) = 0.9243% X 0.0068=0.0006% uc(wS) =0.0104%x 0.0486=0.0006%uc(Wp) =0.0348%X 0.0261=0.0009%10擴(kuò)展不確定度評(píng)定取95%置信水平，包含因子k=2,UC =