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 drafted according to rules given in GB/T 1.1-2009.
This standard supersedes "Standard Test Method for Spark Discharge Atomic Emission Spectrometric Analysis of Carbon and Low-alloy Steel (Routine Method)" (GB/T 4336-2002); compared with the latter, the main technical changes in this standard are as follows:
- The standard name is changed to "Carbon and Low-alloy Steel - Determination of Multi-element Contents - Spark Discharge Atomic Emission Spectrometric Method (Routine Method)";
- The determination scope of each element in Table 1 is modified;
- Documents referred in "Normative References" (Chapter 2) are added;
- The principle description specified in "Principle" (Chapter 3) is modified;
- The description of excitation light source in 4.1 is modified;
- The description of spark chamber in 4.2 is modified;
- The argon purity requirements in 4.3 are modified, and the position of instrument with constant argon pressure and flow is specified;
- The description of electrode in 4.4 is modified;
- The focal length and wave length range in 4.5 are modified;
- The description of photometric system in 4.6 is modified;
- Chapter 6 is changed to "Standard Sample, Standardization Sample and Control Sample" from "Standard Sample and Recalibration Sample", and the description is also modified accordingly;
- "Calibration" (Chapter 8) and its description are added;
- The former Chapter 8 "Analysis Conditions and Analysis Procedures" is changed to Chapter 9, and the description is also modified;
- The former Chapter 10 "Precision" is changed to Chapter 11; the repeatability limit and reproducibility limit formulas of each element are worked out again according to the precision test result;
- "Acceptability of Measuring Result and Determination of Final Report Result" (Chapter 12) is added;
- "Accuracy Judgment for Measuring Result in Laboratory" (Chapter 13) is added;
- "Test Report" (Chapter 14) is added;
- Appendix A and Appendix B (both are informative) are added.
This standard is proposed by China Iron and Steel Association.
This standard is under the jurisdiction of the National Technical Committee on Iron and Steel of Standardization Administration of China (SAC/TC 183).
Drafting organizations of this standard: Central Iron & Steel Research Institute, Baosteel Group Co., Ltd., Wuhan Iron and Steel (Group) Corporation, Angang Steel Company Limited, Shanxi Taigang Stainless Steel Co., Ltd., Hengyang Valin Steel Tube Co. Ltd., Jiugang Steel (group) Co., Ltd., Institute of Metal Research, Chinese Academy of Sciences, National Center For Quality Supervision & Test of Steel Material Products, NCS Testing Technology Co., Ltd., Shimadzu Enterprise Management (China) Co., Ltd., Oxford Instruments (Shanghai) Co., Ltd., Yantai Dongfang Analytical Instruments Co., Ltd. and Focused Photonics (Hangzhou), Inc.
Chief drafting staff of this standard: Cheng Haiming, Jia Yunhai, Luo Qianhua, Shen Ke, Zhang Ye, Yu Yuanjun, Dai Xueqian, Sun Jianjun, Zhao Bin, Ma Hongbo, Guo Dongsheng and Gan Zhengbin.
The previous editions of the standard superseded by this standard are as follows:
- GB/T 4336-1984 and GB/T 4336-2002.
Carbon and Low-alloy Steel - Determination of Multi-element Contents - Spark Discharge Atomic Emission Spectrometric Method (Routine Method)
碳素鋼和中低合金鋼 多元素含量的測定
火花放電原子發射光譜法(常規法)
1 Scope
This standard specifies the method for determining the contents of carbon, silicon, manganese, phosphorus, sulphur, chromium, nickel, tungsten, molybdenum, vanadium, aluminum, titanium, copper, niobium, cobalt, boron, zirconium, arsenic and tin in carbon and low-alloy steel with the spark discharge atomic emission spectrometric method (routine method).
This standard is applicable to the analysis of as-cast or forged carbon and low-alloy steel samples such as electric furnace, induction furnace, electroslag furnace and converter. See Table 1 for the determination scope of each element.
Table 1 Determination Scope of Each Element
Element Determination scope (mass fraction)/%
C 0.03~1.3
Si 0.17~1.2
Mn 0.07~2.2
P 0.01~0.07
S 0.008~0.05
Cr 0.1~3.0
Ni 0.009~4.2
W 0.06~1.7
Mo 0.03~1.2
V 0.1~0.6
Al 0.03~0.16
Ti 0.015~0.5
Cu 0.02~1.0
Nb 0.02~0.12
Co 0.004~0.3
B 0.000 8~0.011
Zr 0.006~0.07
As 0.004~0.014
Sn 0.006~0.02
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the normative document (including any amendments) applies.
GB/T 6379.1 Accuracy (Trueness and Precision) of Measurement Methods and Results - Part 1: General Principles and Definitions
GB/T 6379.2 Accuracy (Trueness and Precision) of Measurement Methods and Results - Part 2: Basic Method for the Determination of Repeatability and Reproducibility of a Standard Measurement Method
GB/T 20066 Steel and Iron - Sampling and Preparation of Samples for the Determination of Chemical Composition
3 Principle
Make the well-prepared block sample discharge with the counter electrode under the action of spark light source to generate plasma in inert atmosphere at high temperature. Where the measured element is excitated, the electron will transit in the atom between different energy levels; the characteristic spectral line will be generated when transiting from high energy level to low energy level; then measure the spectral intensity of characteristic spectral line of the selected analytical element and the internal standard element. Calculate the content of the measured element through calibration curve according to the relation between the spectral line intensity (or intensity ratio) and the concentration of the measured element in sample.
4 Instruments
The spark discharge atomic emission spectrometer is mainly composed of the following units.
4.1 Excitation light source
The excitation light source shall be a stable spark excitation light source.
4.2 Spark chamber
The spark chamber is specially designed for argon, and is directly installed on the spectrometer. It is equipped with an argon flushed spark stand to arrange planar sample and rod counter electrode. The argon gas circuit in spark chamber shall be able to displace the air in the light path between analytical gap and collecting lens, and shall provide argon atmosphere for the analytical gap.
4.3 Argon system
The argon system mainly includes the argon container, two-stage pressure regulator, gas flowmeter and the sequential control part which is able to automatically change the argon flow according to analysis conditions.
The purity and flow of argon have a significant impact on the analysis of measured value; it shall be ensured that the purity of argon shall not be less than 99.995%, otherwise, the argon purification device shall be used, and the pressure and flow of argon in spark chamber shall be maintained constant.
4.4 Counter electrode
Different counter electrodes shall be used for different equipment. Generally, the conical tungsten bar with diameter of 4~8mm and with top processed into 30°~120° or other electrode material is used, and the purity shall be greater than 99%. The flat tip tungsten electrode with diameter of 1mm may also be used. The time for replacing the counter electrode shall be determined by each laboratory according to specific conditions.
4.5 Spectrometer
Generally, the reciprocal of dispersion of first-order spectral line of spectrometer shall be less than 0.6nm/mm, the focal length is within 0.35~1.0m, and the wave length range is 165.0~410.0nm. The vacuum degree of spectrometer shall work blow 3Pa or be filled with high-purity inert gas (such gas does not absorb the spectral line with wave length less than 200nm, and its purity is not lower than 99.999%).
4.6 Photometric system
The photometric system shall include the photoelectric conversion detector receiving signal, the integrating capacitor capable of storing each output electric signal, the measuring unit used for directly or indirectly recording the voltage or frequency on the capacitor, and the necessary circuit switching device provided for the required time sequence.
5 Sampling and Sample Preparation
5.1 Sampling
Sampling and sample preparation shall be in accordance with the requirements of GB/T 20066. During sampling, the analysis sample shall be uniform, and free from shrinkage and crack. During the sampling of as-cast sample, the molten steel shall be injected into the specified mould, the content of deoxidizing agent shall not exceed 0.35% if aluminum deoxidation is adopted; the representative position shall be selected in steel sampling.
5.2 Sample preparation
As for the sample taken out from mould, the sample is generally cut out at the lower 1/3 point in height direction. For the uncut samples, the surface thickness shall be reduced by 1mm. The cutting machine equipped with resin cutting disc and metal-cutting machine tool etc. shall be adopted as the cutting equipment.
The analysis sample shall be sufficient to cover the excitated hole diameter of spark stand, generally, the diameter is required to be greater than 16mm and the thickness be greater than 2mm; the sample surface shall be flat and clean. Grinder, abrasive paper grinding disc or abrasive band grinding machine may be adopted, the miller may also be adopted for processing. Aluminum oxide, zirconium oxide and silicon carbide etc. are adopted as the grinding material. Generally, the particle size of grinding material is 0.25~0.124mm.
The standard sample and analysis sample shall be grinded under the same condition and shall not be overheated.
Note: the selection of different grinding materials may affect the detection of relevant trace elements.
6 Standard Sample, Standardization Sample and Control Sample
6.1 Standard sample
Standard sample is used for plotting calibration curve, of which chemical property and texture structure are similar with those of analysis sample, the content range of analytical element shall be covered and proper gradient shall be maintained, the content of analytical element is valued with accurate and reliable method.
The deviation for analysis result will be generated if improper standard sample series are selected, therefore, adequate attention shall be paid for the selection of standard sample. During the plotting of calibration curve, several standard samples with different analytical element contents are generally adopted as one series, of which composition and smelting processes are better to be similar with those of analysis sample.
6.2 Standardization sample
Variation of instrument conditions will result in deviation of the determination result. In order to directly use the original calibration curve and obtain accurate results, 1~2 samples are used for standardizing the instrument, and such sample is referred to as standardization sample. The standardization sample shall be quite uniform and provided with proper content as required, it may be selected from standard samples and may also be specially smelted. Where two-point standardization is adopted, the contents near the upper limit and lower limit of the calibration curve of each element are respectively taken as its content.
Standardization sample is intended to correct the deviation of calibration curve caused by the measured value of instrument due to various causes, the standardization sample shall be uniform and stable spectral line intensity shall be obtained.
Foreword I
1 Scope
2 Normative References
3 Principle
4 Instruments
5 Sampling and Sample Preparation
6 Standard Sample, Standardization Sample and Control Sample
7 Instrument Preparation
8 Calibration
9 Analysis Conditions and Analysis Procedures
10 Calculation of Analysis Result
11 Precision
12 Acceptability of Measuring Result and Determination of Final Report Result
13 Accuracy Judgment for Measuring Result in Laboratory
14 Test Report
Appendix A (Informative) Additional Information on Precision Experiment
Appendix B (Informative) Precision Data
碳素鋼和中低合金鋼 多元素含量的測定
火花放電原子發射光譜法(常規法)
1 范圍
本標準規定了用火花放電原子發射光譜法(常規法)測定碳素鋼和中低合金鋼中碳、硅、錳、磷、硫、鉻、鎳、鎢、鉬、釩、鋁、鈦、銅、鈮、鈷、硼、鋯、砷和錫含量的方法。
本標準適用于電爐、感應爐、電渣爐、轉爐等鑄態或鍛軋的碳素鋼和中低合金鋼樣品分析，各元素測定范圍見表1。
表1 各元素測定范圍
元 素 測定范圍(質量分數)/％
C 0.03～1.3
Si 0.17～1.2
Mn 0.07～2.2
P 0.01～0.07
S 0.008～0.05
Cr 0.1～3.0
Ni 0.009～4.2
W 0.06～1.7
Mo 0.03～1.2
V 0.1～0.6
Al 0.03～0.16
Ti 0.015～0.5
Cu 0.02～1.0
Nb 0.02～0.12
Co 0.004～0.3
B 0.000 8～0.011
Zr 0.006～0.07
As 0.004～0.014
Sn 0.006～0.02
2規范性引用文件
下列文件對于本文件的應用是必不可少的。凡是注日期的引用文件，僅注日期的版本適用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改單)適用于本文件。
GB/T 6379.1測量方法與結果的準確度(正確度與精密度) 第1部分：總則與定義
GB/T 6379.2測量方法與結果的準確度(正確度與精密度) 第2部分：確定標準測量方法重復性與再現性的基本方法
GB/T 20066鋼和鐵 化學成分測定用試樣的取樣和制樣方法
3原理
將制備好的塊狀樣品在火花光源的作用下與對電極之間發生放電，在高溫和惰性氣氛中產生等離子體。被測元素的原子被激發時，電子在原子內不同能級間躍遷，當由高能級向低能級躍遷時產生特征譜線，測量選定的分析元素和內標元素特征譜線的光譜強度。根據樣品中被測元素譜線強度(或強度比)與濃度的關系，通過校準曲線計算被測元素的含量。
4儀器
火花放電原子發射光譜儀主要由以下單元組成。
4.1激發光源
激發光源應是一個穩定的火花激發光源。
4.2火花室
火花室是為使用氬氣而專門設計的，火花室直接裝在分光計上，有一個氬氣沖洗火花架，以放置平面樣品和棒狀對電極。火花室的氬氣氣路應能置換分析間隙和聚光鏡之間光路中的空氣，并為分析間隙提供氬氣氣氛。
4.3氬氣系統
氬氣系統主要包括氬氣容器、兩級壓力調節器、氣體流量計和能夠按照分析條件自動改變氬氣流量的時序控制部分。
氬氣的純度及流量對分析測量值有很大的影響，應保證氬氣的純度不小于99.995％，否則應使用氬氣凈化裝置，且火花室內氬氣的壓力和流量應保持恒定。
4.4對電極
不同型號的設備使用不同的對電極。一般使用直徑為4 mm～8 mm，頂端加工成30°～120°的圓錐型鎢棒或其他電極材料，其純度應大于99％。也可使用直徑為1 mm的平頭鎢電極。每個實驗室根據具體情況確定更換對電極的時間。
4.5分光計
一般分光計的一級光譜線色散的倒數應小于0.6 nm/mm，焦距為0.35 m～1.0 m，波長范圍為165.0 nm～410.0 nm，分光計的真空度應在3 Pa以下工作，或充高純惰性氣體(該氣體不吸收波長小于200 nm譜線，且純度不低于99.999％)。
4.6 測光系統
測光系統應包括接收信號的光電轉換檢測器、能存儲每一個輸出電信號的積分電容器、直接或間接記錄積分器上電壓或頻率的測量單元和為所需要的時序而提供的必要的開關電路裝置。
5取樣和樣品制備
5.1 取樣
按照GB/T 20066的規定取樣和制樣。取樣時應保證取出的分析樣品均勻、無縮孔和裂紋。鑄態樣品取樣時，應將鋼水注入規定的模具中，用鋁脫氧時，脫氧劑含量不應超過0.35％；鋼材取樣時，應選取具有代表性部位。
5.2樣品的制備
從模具中取出的樣品，一般在高度方向的下端1/3處截取樣品。未經切割的樣品，其表面應去掉1 mm的厚度。切割設備采用裝有樹脂切割片的切割機、金屬切削機床等。
分析樣品應足夠覆蓋火花架激發孔徑，通常要求直徑大于16 mm，厚度大于2 mm，并保證樣品表面平整、潔凈。研磨設備可采用砂輪機、砂紙磨盤或砂帶研磨機，亦可采用銑床等加工。研磨材料有氧化鋁、氧化鋯和碳化硅等。研磨材質的粒度通常為0.25 mm～0.124 mm。
標準樣品和分析樣品應在同一條件下研磨，不得過熱。
注：選擇不同的研磨材料可能對相關的痕量元素檢測帶來影響。
6標準樣品、標準化樣品和控制樣品
6.1標準樣品
標準樣品是為繪制校準曲線使用的，其化學性質和組織結構應與分析樣品相近似，應涵蓋分析元素的含量范圍，并保持適當的梯度，分析元素的含量系用準確可靠的方法定值。
選擇不適當的標準樣品系列會使分析結果產生偏差，因此，對標準樣品的選擇應充分注意。在繪制校準曲線時，通常使用幾個分析元素含量不同的標準樣品作為一個系列，其組成和冶煉過程最好與分析樣品近似。
6.2標準化樣品
由于儀器狀態的變化，導致測定結果的偏離，為直接利用原始校準曲線，求出準確結果，用1個～2個樣品對儀器進行標準化，這種樣品稱為標準化樣品。該樣品應非常均勻并要求有適當的含量，可以從標準樣品中選出，也可專門冶煉。當使用兩點標準化時，其含量分別取每個元素校準曲線上限和下限附近的含量。
標準化樣品是用來修正由于各種原因引起的儀器測量值對校準曲線的偏離，標準化樣品應均勻并能得到穩定的譜線強度。
6.3控制樣品
控制樣品是與分析樣品有相似的冶金加工過程、相近的組織結構和化學成分，用于對分析樣品測定結果進行校正的均勻樣品，可以用于類型標準化修正。
控制樣品可通過取自熔融狀金屬鑄模成型或金屬成品進行自制；在冶煉控制樣品時，應適當規定各元素含量，使各樣品的基體成分大致相等；對控制樣品賦值時，應注意標準值定值誤差以及數據、方法的可溯源性。
7儀器的準備
7.1儀器的存放
光譜儀應按儀器廠家推薦的要求，放置在防震、潔凈的實驗室中，通常室內溫度保持在15℃～30℃，相對濕度應小于80％。在同一個標準化周期內，室內溫度變化不超過5℃。
7.2 電源
為保證儀器的穩定性，電源電壓變化應小于±10％，頻率變化小于±2％，保證交流電源為正弦波。根據儀器使用要求，配備專用地線。
7.3激發光源
為使激發光源電器部分工作穩定，開始工作前應使其有適當的通電時間。
用電壓調節器或穩壓器設備將供電電壓調整到儀器所要求的數值。
7.4對電極
對電極需定期清理、更換并用極距規調整分析間隙的距離，使其保持正常工作狀態。
7.5光學系統
聚光鏡應定期清理，定期描跡來校正入射狹縫位置。
7.6 測光系統
停機后，重新開機，一般應保證足夠的通電時間，使測光系統工作穩定。
通過制作預燃曲線選擇分析元素的適當預燃時間。積分時間是以分析精度為基礎進行實驗確定的。
8 校準
8.1校準曲線法
在所選定的工作條件下，激發一系列標準樣品，原則上使用5個水平以上的標準樣品，每個樣品至少激發3次，繪制分析元素的發光強度(或強度比)與含量(或含量比)的關系曲線作為校準曲線。使用該校準曲線，測量樣品中的元素含量。
8.2原始校準曲線法
原始校準曲線法是先使用校準曲線法繪制校準曲線。當光譜儀器因溫度、濕度、震動等因素導致譜線產生位移，或因發光強度變化導致校準曲線發生漂移時，通過標準化樣品對校準曲線的漂移進行整體標準化修正，使修正后的元素強度恢復到最初建立校準曲線時強度的方法。
8.3控制樣品法
由于分析樣品與繪制校準曲線的標準樣品存在冶煉工藝過程和組織結構的差異，常使校準曲線發生變化。為避免這種差異造成的影響，通常使用與分析樣品的冶金工藝過程和組織結構相近的控制樣品，用于控制分析樣品的分析結果。
首先利用標準樣品制作原始校準曲線，在日常分析時，在同樣的工作條件下，將控制樣品與分析樣品同時分析，利用控制樣品的分析結果與其標準值之間的偏差對分析樣品的分析結果進行修正。
9分析條件和分析步驟
9.1 分析條件
本標準推薦的分析條件見表2，分析線與內標線列入表3中。
表2分析條件
項目 內容
分析間隙 3 mm～6 mm
氬氣流量 沖洗：3 L/min～15 L/min
測量：2.5 L/min～10 L/min
靜止：0 L/min～1 L/min
預燃時間 3 s～20 s
積分時間 2 s～20 s
放電形式 預燃期間高能放電，積分期間低能放電
表3推薦的內標線和分析線
元素 波長/nm 可能干擾的元素
Fe 187.7(內標線)
271.4(內標線)
273.0(內標線)
287.2(內標線)
C 165.81
193.09
Al、Mo、Co、Cr、W、Mn、Ni
Si 181.69
212.41
251.61
288.16 Ti、V、Mo
C、Nb
Ti、V、Mo、Mn
Mo、Cr、W、Al
Mn 192.12
263.80
293.30
Cr、Si、Mo
P 177.49
178.28 Cu、Mn、Ni
Ni、Cr、Al
S 180.73 Si、Ni、Mn、Cr
表3(續)
元素 波長/nm 可能干擾的元素
Cr 206.54
267.71
286.25
298.91
Mo、V
Si、Ni
V、Mo、Ni
Ni 218.49
227.70
231.60 Cr、Mn
Cr、Mn、Si、Mo
W 202.99
209.86
220.44
400.87
Ti
Al、Ni、V、Cr
Ti、Mn
Mo 202.03
203.84
277.53
281.61
386.41
Mn
Mn、Ni
Mn、V、Si
Mn、V
V 214.09
290.88
310.22
311.07
311.67
Al、Mn、Cr、Ti
Cr、Mn、Nb
Al 186.27
199.05
308.21
394.40
396.15
Si、Cr、V、Mo、Ni
Ni、V、Mo、Cr、Mn
Si、Cr、V、Mo、Ni
Ti 190.86
324.19
334.90
337.28
W
Cu 211.20
212.30
224.26
327.39
337.20
Si、Mn
Cr、Ni、W
Nb、Si、W
Ni、Mo
Nb 210.94
224.20
313.10
319.50
Cu、Ni、V
Ti、Cr、V、Ni、Si
Ti、V、Ni、Cr
表3(續)
元素 波長/nm 可能干擾的元素
Co 228.61
258.03
345.35 Mo、Ni
Mo、Ni、V、W、Ti、Si
B 182.59
182.64 S
Mo、Mn、Ni
Zr 179.00
339.19
343.82
349.62
Cr、Cu、Mo、Ti、Ni
Ni
As 197.26
189.04
228.81
234.98
Cr、W
Sn 189.99
317.51
326.23 Cr、Al、Mn
9.2分析步驟
9.2.1按7.2～7.6的要求準備好儀器。
9.2.2分析工作前，先激發一塊樣品2次～5次，確認儀器處于最佳工作狀態。
9.2.3校準曲線的標準化：在所選定的工作條件下，激發標準化樣品，每個樣品至少激發3次，對校準曲線進行校正。儀器出現重大改變或原始校準曲線因漂移超出校正范圍時，需重新繪制校準曲線。
9.2.4校準曲線的確認：分析被測樣品前，先用至少一個標準樣品對校準曲線進行確認。在滿足第12章規定的測量精密度的基礎上，測量結果與認定值之差應滿足第13章的要求，否則，應重新進行標準化。
9.2.5必要時，可選擇控制樣品，用于校正分析樣品與繪制工作曲線樣品存在的較大差異。
9.2.6按9.2.2選定的工作條件激發分析樣品，每個樣品至少激發2次(樣品激發1次，獲得1個獨立測量結果；在樣品激發點的對面位置再激發1次，獲得第2個獨立測量結果)。按第12章的要求，判斷測量結果的可接受性，并確定最終報告結果。
10分析結果的計算
根據分析線的相對強度(或絕對強度)，從校準曲線上求出分析元素的含量。
待測元素的分析結果，應在校準曲線所用的一系列標準樣品的含量范圍內。
11精密度
本標準的精密度試驗分別在2013年由15個實驗室對低合金鋼中14元素的11個～22個水平進行測定，以及在2014年由12個實驗室對中低合金鋼中的5個元素的18個～36個水平進行測定。按照GB/T 6379.1規定的重復性條件下，每個實驗室對每個水平的元素含量測定2次。
所用試樣列于附錄A中表A.1～表A.19。
按照GB/T 6379.2，對得到的結果進行統計處理。各元素的含量與試驗結果的重復性限r和再現性限R的函數關系式匯總于表4。
