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GB/T 223.5-2008 PDF in English


GB/T 223.5-2008 (GB/T223.5-2008, GBT 223.5-2008, GBT223.5-2008)
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GB/T 223.5-2008: PDF in English (GBT 223.5-2008)

GB/T 223.5-2008
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.080.01
H 11
Replacing GB/T 223.5-1997
Steel and iron - Determination of acid-soluble silicon
and total silicon content - Reduced molybdosilicate
spectrophotometric method
(ISO 4829-1:1986 Steel and cast iron - Determination of total silicon content -
Reduced molybosilicate spectrophotometric method - Part 1: Silicon contents
between 0.05 and 1.0% & ISO 4829-2:1988 Steel and iron - Determination of
total silicon content - Reduced molybosilicate spectrophotometric method -
Part 2: Silicon contents between 0.01 and 0.5%, MOD)
ISSUED ON: AUGUST 19, 2008
IMPLEMENTED ON: APRIL 01, 2009
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Normative references ... 5 
3 Principles ... 6 
4 Reagents and materials ... 6 
5 Instruments and equipment ... 7 
6 Taking and preparation of specimens ... 8 
7 Analytical procedures ... 8 
8 Expression of results ... 12 
9 Test report ... 13 
Appendix A (Informative) International joint trial additional information ... 15 
Appendix B (Informative) Diagram of precision data ... 17 
Foreword
This part of GB/T 223 modifies and adopts ISO 4829-1:1986 “Steel and cast
iron - Determination of total silicon content - Reduced molybosilicate
spectrophotometric method - Part 1: Silicon contents between 0.05 and 1.0%”
and ISO 4829-2:1988 “Steel and iron - Determination of total silicon content -
Reduced molybosilicate spectrophotometric method - Part 2: Silicon contents
between 0.01 and 0.5%”. It integrates them into one standard.
The principles, dissolved acid, color development system, measurement
methods of this part are consistent with ISO 4829-1:1986 and ISO 4829-2:1988.
Without prejudice to the accuracy and precision of the method, it mainly makes
the following modifications:
- CHANGE “after the original sample is processed, dilute the test solution in
a 1000 mL volumetric flask to make its volume reach to the mark” into “dilute
the test solution in a 100 mL volumetric flask to make its volume reach to
the mark”, which accordingly reduces the amount of dissolved acid and the
amount of divided color-developing solution.
- CHANGE the amount of original sample from 0.50 g to “respectively weigh
0.40 g, 0.20 g, or 0.10 g”.
- CHANGE “the original residue is melted by solidum peroxide in a zirconium
crucible at 600 °C” into “it is melted by sodium carbonate-boric acid mixed
flux in a platinum crucible at 950 °C”.
- CHANGE “the original content of pure iron silicon is less than 5 μg/g and 2
μg/g, respectively” into “the content of pure iron silicon is less than 0.002%
(mass fraction); and the exact content is known”.
- CHANGE “when drawing the calibration curve, weigh several parts of pure
iron; after it is decomposed by mixed acid, respectively add different
amount of silicon standard solution” into “weigh one part of pure iron; add
mixed acid to decompose it and make its volume reach to the mark. After
liquid separation, respectively add different amount of silicon standard
solution”. The concentration of the silicon standard solution in the reagent
is also modified accordingly.
- MODIFY the calculation formula of the analytical results.
This part replaces GB/T 223.5-1997 “Methods for chemical analysis of iron,
steel and alloy - The reduced molybdosilicate spectrophotometric method for
the determination of acid-soluble silicon content”.
As compared with GB/T 223.5-1997, this part mainly made the following
Steel and iron - Determination of acid-soluble silicon
and total silicon content - Reduced molybdosilicate
spectrophotometric method
WARNING: Personnel who uses this part of GB/T 223 shall have hands-
on experience with formal laboratory work. This part does not address all
possible safety issues. It is the responsibility of the user to take
appropriate safety and health measures and to ensure compliance with
the conditions set by the relevant national regulations.
1 Scope
This part of GB/T 223 specifies the determination of acid-soluble silicon and
total silicon content in steel and iron by the reduced molybdosilicate
spectrophotometric method.
This part applies to the determination of silicon content in steel and iron which
have a mass fraction of 0.010% ~ 1.00%.
2 Normative references
The provisions in following documents become the provisions of this part
through reference in this part of GB/T 223. For the dated references, the
subsequent amendments (excluding corrections) or revisions do not apply to
this part; however, parties who reach an agreement based on this standard are
encouraged to study if the latest versions of these documents are applicable.
For undated references, the latest edition of the referenced document applies.
GB/T 6379.1 Accuracy (trueness and precision) of measurement methods
and results - Part 1: General principles and definitions (GB/T 6379.1-2004,
ISO 5725-1:1994, IDT)
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 6379.2-2004, ISO
5725-2:1994, IDT)
GB/T 20066 Steel and iron - Sampling and preparation of samples for the
1.42 g/mL). After cooling, use water to dilute it to 1000 mL; mix it uniformly.
4.7 Potassium permanganate solution, 22.5 g/L. Dissolve 2.25 g of potassium
permanganate in 50 mL of water. Use water to dilute it to 1000 mL. Mix it
uniformly. Filter it before use.
4.8 Hydrogen peroxide solution, 1 + 4.
4.9 Sodium molybdate solution: Dissolve 2.5 g of sodium molybdate dihydrate
(Na2MoO4 • 2H2O) in 50 mL of water. Use the medium-density filter paper to
filter it. Before use, add 15 mL of sulfuric acid (4.4). Use water to dilute it to 100
mL. Mix it uniformly.
4.10 Oxalic acid solution, 50 g/L. Dissolve 5 g of oxalic acid dihydrate (C2H2O4
• 2H2O) in water. Use water to dilute it to 100 mL. Mix it uniformly.
4.11 Ascorbic acid solution, 20 g/L. Dissolve 2 g of ascorbic acid in 50 mL of
water. Use water to dilute it to 100 mL. Mix it uniformly. Prepare it before use.
4.12 Silicon standard solution
4.12.1 Silicon stock solution, 0.50 mg/mL. Weigh 1.0697 g of high-purity silica
(mass fraction > 99.9%) which was fired at 1100 °C for 1 h and cooled to room
temperature. Place it in a platinum crucible. Add 10 g of anhydrous sodium
carbonate. Mix it uniformly. Melt it at 1050 °C for 30 min. In a polypropylene or
Teflon beaker, use 100 mL of water to leach out the melt (see note). Transfer
all the dissolved leachate to a 1000 mL single-line volumetric flask. Use water
to dilute it to the mark. Mix it uniformly. Immediately transfer it into a sealed
Teflon bottle for storage. 1 mL of this stock solution contains 0.500 mg of silicon.
Note: Leaching of melt may require slow heating.
4.12.2 Silicon standard solution, 10.0 μg/mL. Pipette 20.00 mL of silicon stock
solution (4.12.1) into a 1000 mL single-line volumetric flask. Use water to dilute
it to the mark. Mix it uniformly. Immediately transfer it to a sealed Teflon bottle
for storage. Prepare it before use. 1 mL of this standard solution contains 10.0
μg of silicon.
4.12.3 Silicon standard solution, 4.0 μg/mL. Pipette 100.00 mL of silicon stock
solution (4.12.2) into a 250 mL single-line volumetric flask. Use water to dilute
it to the mark. Mix it uniformly. Immediately transfer it to a sealed Teflon bottle
for storage. Prepare it before use. 1 mL of this standard solution contains 4.0
μg of silicon.
5 Instruments and equipment
Common laboratory instruments and equipment.
acid (4.5). When weigh it to 0.40 g, add 30 mL of the mixed acid of sulfuric acid-
nitric acid (4.5). Cover the lid. Slightly heat to dissolve the sample. In this
process, continuously add water, to keep the volume of the solution from
significant reduction.
Or put the sample (7.1) in a 250 mL polypropylene or Teflon beaker (5.1). When
weigh it to 0.20 g and 0.10 g, add 15 mL of the mixed acid of sulfuric acid-nitric
acid (4.6). When weigh it to 0.40 g, add 20 mL of the mixed acid of sulfuric acid-
nitric acid (4.6). Cover the lid. Slightly heat to dissolve the sample. In this
process, continuously add water, to keep the volume of the solution from
significant reduction.
Use water to dilute it to about 60 mL. Carefully heat the test solution to boiling.
Add potassium permanganate solution (4.7) until the precipitated hydrated
manganese dioxide settles. Keep it slightly boiling for 2 min. Add hydrogen
peroxide (4.8) dropwise to the point when the manganese dioxide precipitate
dissolves. Heat to slightly boil it for 5 min, to decompose the hydrogen peroxide.
Cool it down. Transfer the test solution to a 100 mL single-line volumetric flask.
Use water to dilute it to the mark. Mix it uniformly.
7.3.2 Decomposition of sample and preparation of test solution for
determination of total silicon
Place the sample (7.1) in a 250 mL polypropylene or Teflon beaker (5.1). When
weigh it to 0.20 g and 0.10 g, add 30 mL of the mixed acid of sulfuric acid-nitric
acid (4.5). When weigh it to 0.40 g, add 35 mL of the mixed acid of sulfuric acid-
nitric acid (4.5). Cover the lid. Slightly heat to dissolve the sample. In this
process, continuously add water, to keep the volume of the solution from
significant reduction.
Or put the sample (7.1) in a 250 mL polypropylene or Teflon beaker (5.1). When
weigh it to 0.20 g and 0.10 g, add 20 mL of the mixed acid of sulfuric acid-nitric
acid (4.6). When weigh it to 0.40 g, add 25 mL of the mixed acid of sulfuric acid-
nitric acid (4.6). Cover the lid. Slightly heat to dissolve the sample. In this
process, continuously add water, to keep the volume of the solution from
significant reduction.
When the solution’s reaction stops, use the low-ash low-speed filter paper to
filter the solution. Collect the filtrate in a 250 mL beaker. Use 30 mL of hot water
to rinse the beaker and filter paper. Use a rod which has a rubber head to wipe
off the particles which are attached to the wall of the beaker. Transfer them all
onto the filter paper.
Place the filter paper and residue in a platinum crucible (5.2). Dry it. Ash it. Burn
it at 950 °C in a high-temperature furnace. After cooling, add 0.25 g of the mixed
flux (4.2) to mix the residue. Then cover 0.25 g of the mixed flux (4.2). Melt it at
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.