ASTM E1937-97

Standard Test Method for Determination of Nitrogen in Titanium and Titanium Alloys by the Inert Gas Fusion Technique

SCOPE
1.1 This test method provides a procedure for the determination of nitrogen in titanium and titanium alloys in concentrations from 0.007 to 0.11%.  
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Dec-1997
• ICS: 77.120.50 - Titanium and titanium alloys
• Technical Committee: E01 - Analytical Chemistry for Metals, Ores, and Related Materials
• Drafting Committee: E01.06 - Ti, Zr, W, Mo, Ta, Nb, Hf, Re

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E 1937 – 97
Standard Test Method for
Determination of Nitrogen in Titanium and Titanium Alloys
by the Inert Gas Fusion Technique
This standard is issued under the fixed designation E 1937; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method provides a procedure for the determi-
nation of nitrogen in titanium and titanium alloys in concen-
trations from 0.007 to 0.11 %.
1.2 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. Specific hazards
statements are given in 7.8 and Section 8.
2. Referenced Documents
2.1 ASTM Standards:
E 50 Practices for Apparatus, Reagents, and Safety Precau-
tions for Chemical Analysis of Metals
E 173 Practice For Conducting Interlaboratory Studies of
Methods For Chemical Analysis of Metals
3. Summary of Test Method
3.1 This test method is intended for use with automated,
commercially available inert gas fusion analyzers.
3.2 The test sample, plus flux, is fused in a graphite crucible
in a flowing helium gas stream at a temperature sufficient to
release nitrogen. The nitrogen is swept by the helium gas
stream into a thermal conductivity detector. The detector
response is compared to that of calibration standards and the
FIG. 1 Apparatus for Determination of Nitrogen by the Inert Gas
result is displayed as percent nitrogen.
Fusion-Thermal Conductivity Method
3.3 In a typical instrument (Fig. 1) the sample gases are
swept with helium through heated rare earth/copper oxide
which converts CO to CO and H to H O. The CO is
4. Significance and Use
2 2 2 2
absorbed on sodium hydroxide impregnated on clay, and the
4.1 This test method is primarily intended as a referee
H O is removed with magnesium perchlorate. The nitrogen, as
method for compliance with compositional specifications. It is
N , enters the measuring cell and the thermistor bridge output
assumed that all who use this test method will be trained
is integrated and processed to display percent nitrogen.
analysts capable of performing common laboratory procedures
skillfully and safely. It is expected that the work will be
performed in a properly equipped laboratory.
This test method is under the jurisdiction of ASTM Committee E-1 on
Analytical Chemistry for Metals, Ores and Related Materials and is the direct
responsibility of Subcommittee E01.06 on Titanium, Zirconium, Tungsten, Molyb-
5. Interferences
denum, Tantalum, Niobium, Hafnium, and Rhenium.
5.1 The elements usually present in titanium and its alloys
Current edition approved Dec. 10, 1997. Published August 1998.
Annual Book of ASTM Standards, Vol 03.05. do not interfere.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E 1937
6. Apparatus and 12.4 to condition the newly changed filters before attempt-
ing to calibrate the system or to determine the value of the
6.1 Instrument—The general features of the typical instru-
blank.
ment are shown in Fig. 1.
6.2 Graphite Crucibles, made of high-purity graphite of the
10. Nickel Flux Preparation
dimensions recommended by the instrument manufacturer.
10.1 Nickel is necessary to flux the titanium fusion reaction
6.3 Flux—Wire baskets consisting of platinum or high-
but contamination can be present on the surface of the nickel
purity nickel of dimensions that meet the requirements of the
wire baskets that must be removed before use.
automatic sample drop, if present, on the instrument (Note 1).
10.2 Immerse the flux in Nickel Flux Cleaning Solution for
NOTE 1—In some instruments, nitrogen and oxygen are run sequen-
50 to 60 s, then rise in running water for 2 to 3 min. Pour flux
tially and platinum is the required flux for nitrogen. High purity platinum
onto paper towels to remove excess water. Place flux in
can be substituted for nickel in the same weight ratio of flux to sample.
sealable glass container, rinse with acetone and decant. Re-
When using platinum as a flux, graphite powder should not be added to the
place with fresh acetone and store flux under acetone until use.
crucible.
11. Sample Preparation
6.4 Tweezers—Six inch solvent and acid-resistant plastic.
11.1 The optimum test sample is a pin approximately ⁄8 in.
7. Reagents
in diameter and nominally weighing 0.12 to 0.15 g. Cut the
sample to this approximate weight range.
7.1 Acetone—Residue after evaporation must be <
11.2 Leach the test sample in the Titanium Sample Pickle
0.0005 %.
Solution until the surface is clean. This will normally require
7.2 Graphite Powder, of purity specified by the instrument
approximately 5 s from the time of the initial vigorous reaction.
manufacturer.
11.3 Immediately remove the reacting test sample with
7.3 Helium, of purity and type specified by the instrument
tweezers and rinse it twice with water and once with acetone
manufacturer.
and then air dry. This test sample should now weigh between
7.4 Magnesium Perchlorate, Anhydrous—Used in the in-
0.100 and 0.140 g.
strument to absorb water. Use the purity specified by the
11.4 All subsequent operations on the test sample and flux
instrument manufacturer. (Known commercially as Anhy-
must be done without introducing contamination to either. Use
drone.)
only clean tweezers and never let the test sample or flux contact
7.5 Nickel Flux Cleaning Solution—Prepare a fresh solution
the analyst’s skin. In the event this does happen, rinse the
of nickel cleaning solution by combining 75 mL of acetic acid,
sample plus nickel basket with acetone and air dry before
25 mL of HNO and 2 mL of HC1.
analysis.
7.6 Rare Earth/Copper Oxide—Reagent used in the instru-
ment to oxidize CO to CO . Use the purity specified by the
12. Calibration
instrument manufacturer.
12.1 Calibration Standards—Select only titanium or tita-
7.7 Sodium Hydroxide on Clay—Reagent used in some
nium alloy standards. Select one containing approximately
instruments to absorb CO . Use a purity specified by the
0.02 % nitrogen. The accuracy of the test method is dependent
instrument manufacturer. (Known commercially as Ascarite
upon the accuracy of the methods used to certify the nitrogen
II.)
concentration of the certified reference materials, as well as
7.8 Titanium Sample Pickle Solution—Prepare a fresh solu-
upon the their homogeneity. Thus, wherever possible, stan-
tion of 3 parts 30 % H O and 1 part
...