Ferrous Metallurgy W. A. Straub* and J. K. Hurwitz United States Steel Corporation, Research laboratory, 125 Jamison lane, Monroeville, Pa. 15 146
This review covers the period from November 1974 through October 1976, and is a continuation of previous reviews. The search of Chemical Abstracts was aided by the Knowledge Availability Service Center a t the University of Pittsburgh. Following nearly all citations in the Literature Cited, the Chemical Abstract (CA) volume and abstract numbers are given. Because of the worldwide interest in manganese nodules, references to the analysis of this material are cited. Special references are also made to papers describing surface-analysis techniques and data acquisition and reduction with the aid of microprocessors and computers.
BOOKS AND REVIEWS Books describing the analyses of metals, ores, rocks, and minerals have been published (24,55,102,212), as have extensive reviews of ore and rock analysis (638),the analysis of taconites, iron ores, and metallurgical products (747),British Steel Corp. steel works’ materials (511),JIS methods for iron and steel (740), analysis of cast irons and steels (590, 757), alloy steel analyses (534), and new instrumental methods (687).
Atomic Absorption. Reviews have appeared on the application of atomic absorption spectrometry to the analysis of ferrous metals and alloys in English (63, 521, 597) and Japanese (200). Emission Spectrometry. Several reviews on the theory and application of emission spectrometry to ferrous analysis (259,347,573)have been written. X-ray Fluorescence Spectrometry. Discussions have been given of the use of x-ray methods for the analysis of steels, cast irons, ores, slags, sinters, and electroplates (4,454, 486, 748);two reviews have been published comparing the use of various spectral methods (including emission, x-ray, atomic absorption, and spark source-mass spectrometry) ( I 06, 393). Other Spectral Methods. A number of reviews on specific spectroscopic methods as applied to ferrous metallurgical problems have been written and include the use of Auger electron spectroscopy (296, 676), Mossbauer spectroscopy (644),ion-microprobe mass analyzers (257,296,4421, spark source-mass spectroscopy (706),and various x-ray emission and photoelectron techniques (296). Neutron Activation. Activation techniques have been reviewed for the analysis of ores, coals, steels (568), pure , ferrous metals (718, 751). metals ( l l ) and Gases in Metals. The analysis of steels and ferroalloys for gases has been reviewed, with respect to oxygen, nitrogen, and hydrogen content (50,152,164,435,649,761,784),oxygen and nitrogen (440, 751), nitrogen (388), and hydrogen (436). Methods for the extraction and determination of nonmetallic inclusions in steels have been summarized (466). Other Reviews. Analytical methods for the determination of niobium and carbon have been critically reviewed (711, 768). ALUMINUM Atomic Absorption. This element has been determined a t low levels in nitrous oxide-acetylene flames in steels (20, 265,301,681) and ferrosilicon (157),slags (23),and ores (264), and with a graphite tube furnace (35,698). Micro methods by flame (147) and graphite tube (39) have also appeared. Automatic sampling for atomic absorption analysis of steels was optimized (282),and a repetitive optical scanning method for flame emission analysis of ferrous materials (561) has been given. Volumetric. The compleximetric determination of aluminum in ferroboron (683)and dolomite (583)has been reported. 54R
ANALYTICAL CHEMISTRY, VOL. 49, NO. 5, APRIL 1977
Spectrophotometry. Methods have been published for steel analysis with aluminon (175, 181, 398), a-hydroxy-a(dibutylphosphiny1)propionic acid (449),alumocreson (572), chromazol KS (57),chromazurol S (686),and oxine (285),and for ferrosilicon with xylenol orange (682).Automated spectrophotometric methods have been developed for analysis of steels (665)and sinters (74). Emission Spectrometry. Heat resistant (703),maraging (648),high alloy (660),and stainless steels (670)and cast iron (739) have all been analyzed for aluminum. Laser microspectrochemical methods have been published for steel (598) and single-crystal iron (367).Periodic alternation of excitation modes has been applied to the determination of iron and aluminum in ferroaluminum (607),whereas open hearth slags (341) and ferrochrome analysis (245) have also been reported. X-ray Fluorescence. Generalized methods for the analysis of slags (40, 750) and oxidic materials (704, 707) have appeared. Electron probe microanalyses (733)have been compared with chemical analyses of the same steels. Nuclear Methods. Trace levels of aluminum in iron and steel have been measured (240,525),following 14-MeV neutron activation, whereas higher levels have been determined in steels (269,3281,oxides @69),and slags and ferrochromium (744).Iron ores have been assaved followina thermal neutron activation (95,419). Electrochemical. An electrographic method has been described for aluminum detection (669.671)in stainless steels, and an EMF method has been used for aluminum measure: ment by employing the relationship between oxygen activity and aluminum content of molten steel (280). I
ANTIMONY Atomic Absorption. Antimony has been analyzed following acid dissolution of the steel by flameless atomic absorption (53, 225, 564), as the volatile hydride in an argonhydrogen-air flame (219) and as the solid (35) in a graphite furnace. Emission Spectroscopy. Trace quantities were determined by extraction-spectrographic methods in steels (395) and ferromolybdenum ( 170), and directly in several ferroalloys (366).
X-ray Methods. High-purity irons, mild steels, and lowalloy steels have been analyzed (261, 262), and segregated surfaces have been studied by x-ray photoelectron and Auger spectroscopy (145). Other Methods. Coulometry has been applied to antimony-iron alloys ( 3 ) ,and various extractive techniques have been evaluated prior to spectrophotometric analysis of irons and steels (489). ARSENIC Atomic Absorption. Arsenic in steels has been determined following dissolution in nitrous oxide-acetylene flames (250, 681 ), in the graphite furnace (53,564),and as the hydride in an argon-hydrogen-air flame (219,699). Emission Spectroscopy. Trace levels have been determined in ferroalloys following acid dissolution (170,366), and in steel by photoelectric-recording spectrometer (492). Other Methods. Two spectrophotometric methods for arsenic in iron, steel and oxidic materials have been compared (143),ferrotungsten has been assayed polarographically (199), and iron-antimony coulometrically ( 3 ) .Spark source mass spectrometry has been used to determine traces in steel (584).
BARIUM Reduced sinters (543), blast-furnace slags (544), and
William A. Straub, Associate Research Consultant, U S . Steel Corporation, Research Laboratory, Monroeviile, Pa., has been with U.S. Steel since obtaining his Ph.D. from Cornell University in 1958. As a Research Chemist, he has been active mainly in the areas of inclusion analyses by thermal methods and in the application of ion-selective electrodes and other electrochemical devices for both laboratory and plant use, particularly in continuous process monitors. He is a member of the American Chemical Society, has served as the chairman of the Societv for Analytical Chemists of Pittsburgh, and has worked on the Pittsburgh Conference committee in various capacities ~
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J. K. Hurwitr is an Associate Research ConsLltant at the Researcn LaDoratory. Jniteo States Steel Corporation in Monroeville. Pa. Previouslv. he was Senior Scientific Officer at the-Mmes Branch. Government of Canada in Ottawa, Canada h e received his B A Sc in Engineering Physics and M A and PhD in Physics from the University of Toronto. His research interests include method development in emission spectroscopy, spectrochemical applications of computers, development of standard materials for optical and x-ray emission spectrometric analysis, and ion-sputtering sources He is the author or coauther of 26 papers in scientific journals and a book, and has contributed papers to two symposia published by the American Society for Testing and Materials He is an honorary member and a past president of the Spectroscopy Society of Canada and a member and a past secretary of the Society for Applied Spectroscopy
limestones (772) have been analyzed titrimetrically after a preliminary separation of the barium by various methods. BERYLLIUM Chromazurol S has been applied to the spectrophotometric determination of beryllium in cast irons and steels (26, 27), and a spectrographic method for steels (554) has been reported. BISMUTH Atomic Absorptiori. Trace amounts of bismuth in steels (53,227)have been determined by flameless atomic absorption, and in super alloys by both optical emission and atomic absorption (723). Hydride formation has also been used for steel analysis (219) by an argon-hydrogen-entrained air flame. O t h e r Methods. Fexoalloys ( 170, 366) and steels (395) have been analyzed spectrographically, whereas an inverse ac polarographic method has been applied to iron (100). BORON Spectrophotometry. Several automated methods for the determination of trace amounts of boron in steel by using curcumin (498, 499) and methylene blue (350) have been studied, and manual methods utilizing methylene blue and quinalizarin have been applied to iron (553)and ferrosilicon (355),respectively. Emission Spectrometry. Boron was determined by direct excitation in steels (64,407,476,492, 708) and following dissolution in acid, drying and conversion to a volatile fluoride form (13, 14) during excitation. Nuclear Methods. Stainless steel and iron ores (463)and ferroboron (529)have been analyzed by neutron activation, whereas autoradiography has been used to determine the boron distribution in low-alloy steels (731). O t h e r Methods. An ion-microprobe method has been applied to the determination of ppm boron in steels (123),and spark source-mass spectrometry of salts derived from dissolved steels has been recommended (584).Higher levels of boron in surfacing alloys have been measured potentiometrically (503).
CADMIUM Atomic Absorption. Both flame and graphite tube techniques were compared for the determination of cadmium in alloys (53),whereas automatic sampling was incorporated in an atomic absorption method for ores and agglomerates (420). Other Methods. An extraction-spectrographic method has been reported for the ppm determination of cadmium in steels (395), in ferromolybdenum by a solution spectrochemical method ( I 70),in stainless steels by anodic stripping voltammetry (647),and high levels in iron-cadmium sponges by a compleximetric titration method with EDTA (153, 154).
CALCIUM Atomic Absorption. Iron ores (2641, agglomerates (4201, basic oxygen furnace slags (23),and ferrosilicon (157)have all been analyzed by atomic absorption following various chemical dissolution steps. An autosampler was used in one case (420).Micro amounts of calcium in steels have also been reportedly determined by flame photometry (631). Emission Spectrometry. Several methods have been given for the analysis for calcium fluoride (548,555)and for calcium oxide (341) in slags, and for calcium in ball-bearing steels (403). X-ray Fluorescence. A number of methods and instrument evaluations have been published and devoted mainly to the analysis of ores (375,376,473,704, 707),magnesite and dolomite (83),limestone (377),and slags (40, 705). O t h e r Methods. Free lime in slags (458) and calcium in dolomite (583) have been determined by complexometric titrations, and sinter samples have been assayed by AutoAnalyzer methodology (74).Free lime has also been determined by conductivity measurements during extraction into ethylene glycol (754),and extraction chromatography has been applied to the separation and determination of calcium in iron oxides (381).
CARBON Emission Spectrometry. Several papers have been published describing the determination of carbon in steel (141, 142,482,484,492,570,579,694, 743),cast iron (54,249,389, 484), and stainless steel (546, 570, 670). Corrections for interferences on carbon determinations were evaluated and results were calculated with the aid of a computer (141, 142, 694, 743). The influence of sample structure and composition of the counter electrode on carbon determinations was investigated (236),and sample structure was a significant factor. Increased sensitivity for carbon determinations was achieved if helium or argon-oxygen gas mixtures were used as atmospheres (577) for a direct-current pulsed discharge. An ion-sputtering glow-discharge source was used for the vacuum spectrometric analysis of steel and cast iron (560) with excellent repeatability. A plasma jet (434)was developed for the analysis of steel powder. The steel powder was produced with an atomization device and automatically moved into the plasma jet for control analysis of molten steel. Combined isotopic dilution and emission spectrometry (285)was used for determining carbon in steel. Emission spectrometric methods were used to investigate the diffusion of carbon in steel (342, 579) and the distribution of carbon in cast steel (482). Combustion a n d Electrochemical Methods. Carbon was determined in high-purity iron (596)at concentrations as low as 5 parts per million by combustion followed by gas-chromatographic separation. This determination was completed conductometrically after absorption of the resultant carbon dioxide in a weak solution of sodium hydroxide. Carbon was determined in ferrochromium by cohventional combustion methods, except that vanadium pentoxide was used as a flux (508). Several methods appeared in the literature for combustion-coulometric determination of carbon in steel (44,91, 921, high-alloy steels (253),ores (294),and ferrochromium (254). A comparison of several combustion methods was made recently (47). A nonaqueous titration method was recommended to replace a standard gravimetric procedure for determination of low carbon concentrations in steel. ANALYTICAL CHEMISTRY, VOL. 49, NO. 5, APRIL 1977
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Three papers have been published describing methods and apparatus for the indirect determination of carbon in molten steel bv measuring the free oxygen with an electrochemical .cell (Si,619, 766)X-ray Fluorescence Spectrometry and Ion Microprobe Analysis, X-ray fluorescence methods were used to determine the thickness of chromium carbide and titanium carbide diffusion layers on steel (342, 517 ) , concentration of silicon carbide in slag (314). and carbon in carburized steel (182). Ion mTcroprobes iombined with x-ray spectrometers were used to identify carbides in steel alloys (288, 421) and tool steel (258), determine low carbon concentrations in steel (475), investigate the distribution of carbide in welds (422), and determine carbon in ball-bearing steel (70). Activation Analysis. Gamma activation analysis methods (11,549,569)and neutron activation analysis methods (412) were developed for carbon determinations in high-purity iron, iron ore, sinter, and steel.
CHROMIUM Spectrophotometry. Chromium in ores (613) and alloys (646) has been determined as dichromate following silver persulfate oxidation. In the latter case, results compared favorably with emission spectrometric results. Alloy steels have also been assayed with diphenylcarbazole (690),arsenazo (and its analogues) (675), 4-(2-pyridylazo)resorcinol (462), and as the colored chromium(II1)-EDTA complex (456). Electrochemical and Volumetric. Chromium has been titrated coulometrically in steel with electrogenerated copper(1) (385), in chromate ore with electrogenerated ferrous ion (386), amperometrically in steels and ferroalloys with ferrous ammonium sulfate (781), and with carboxymethyldithiocarbamate (714). Ferrous ammonium sulfate was also used in a photometric titration procedure for chromium in steels (657), and chromium was determined polarographically following separation (608). Electrographic sample dissolution was used to provide a sample of steel for analysis by photometry (763, 764). Atomic Absorption. Of the several methods for the determination of chromium in steels, only one method (150) did not remove iron interference. In other procedures, masking with fluoride (220), a mixed salt buffer (151), hexamethylenetetramine (369),and swamping with excess iron (464) have been used. Electrographic separation with subsequent atomic absorption measurement of dissolved chromium has been reported (622).A multielement computer-coupled photodiode array spectrometer has been applied to chromium-containing alloys (308). Emission Spectrometry. Generalized methods continue to appear that describe attempts to reduce matrix effects during spectrographic analysis as follows: for cast irons (54, 450), by solution methods with spark (242,660), and plasma torch (37)excitation, and by a contact-spark sampling method (611, 703) for high alloys. Applications of direct-reading emission spectrometers to stainless-steel (546,570),alloy-steel (5701, and cast-iron (389) analyses have been published. Production control instrumentation for the analysis of molten cast iron (249) and for microspectroscopic analysis of small alloy pieces ( I 71) has been described, and a portable spectroscope has been used for on-site visual determination of 16 elements (68). Laser microspectral analyzers have been employed for steels (77,112,394,598).Matrix effects were studied in two of these methods (77,112). Chromized surfaces have been analyzed directly (342,662) following solution by chemical or electrochemical means (661), and after electro-spark sampling (663). Effects of steel sample structure on spectro raphic results have been studied (237,490),as have the excitafion conditions during sparking (183,401). A statistical evaluation has been made of the determination of chromium in cast iron in solid form and following solution (738). Nuclear Methods. Fourteen-MeV neutrons have been employed for the determination of chromium in stainless steel directly (717), and following separation (594). In-beam activation methods have been presented for pure iron (411) and stainless steel and ore analysis (463), whereas nonreactor sources were applied in steels (529) and ore5 (419). 56R
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X-ray Spectrometry. This technique has been applied to ores (419) and oxidic materials including corrosion films (82, 707), slags (40, 705), ferroalloys such as ferrosilicon and ferrochromium (191), ferromanganese, ferroniobium, ferromolybdenum, ferrotitanium, and ferrovanadium (636), cast iron (552), low alloys (7, 98, 244, 261, 773), and high alloys and stainless steels (120,234,292, 377, 710). Surface, Thin Film, and Profiling Methods. Corrosion and electropolishing films have been analyzed by an x-ray microanalyzer (190) and by ESCA techniques (491). Chromium profiles in stainless steel have been determined by an ion microprobe analyzer (667) and in thin specimens, small particles, and across grain boundaries (207, 465) by electron-microprobe analysis. The calculation of correction coefficients has been described for microprobe determinations (384, 733). Surface analyses by mass spectral methods have been applied to steels (584), stainless steels (377), and to nickel-chromium coated steels (277). Interelement effects have been eliminated by appropriately constructed mathematical models (184, 274, 726) used for x-ray analysis of steels. COBALT Spectrophotometry. Steels have been analyzed for cobalt with picolinaldehyde-4-phenyl-3-thiosemicarbazone(32), 5-chloropyridylazoaminophenol (276), pyridine-2-aldehyde-2-pyridylhydrazone-eosine(2791, 4-(2-pyridylazo)m-phenylenediamine (423), 5-[3,5-dichloro-(2-pyridylazo)]-2,4-diaminotoluene (614), and high temperature alloys have been assayed with 1-nitroso-2-naphthol (286), and ores with nitroso-R salt (532). Emission Spectrometry. Residual impurities in ferrochrome have been determined by a solution-spark technique (245), and high speed steels (611), thin films of iron-cobalt alloys (615), and maraging steels (648) have been analyzed by various spectrochemical methods. X-ray Fluorescence and Nuclear Methods. High-purity irons and low-alloy steels (261, 262) and super alloys (292) have been analyzed directly, and an acid-solution method has been used for plain carboh (98) and stainless steels (710). Manganese nodule analyses by both x-ray fluorescence (536) and neutron activation (634) were reported, and pure iron (411) and steels (160)have also been analyzed by activation methods. Electron microprobe studies have been reported for the determination of cobalt in steels (733) and in manganese nodules (444). Other Methods. Cobalt has been determined gravimetrically in steels as a precipitate of benzoyl-m -nitroacetanilide (430). In contrast, oscillopolarography has been applied to the determination of cobalt in pure iron (550), and direct polarography has been used for high-alloy steels (608). COPPER Spectrophotometry. Extraction-photometric methods have been described for the determination of copper in steel by using 4-(2-pyridylazo)-resorcinol(209), benzoin oximepyridine (243), and diethydithiocarbamate (557) as the color-forming reagents; the last named reagent has also been used for copper in slags and ferroalloys (650) following caproic acid extraction. Atomic Absorption. Several reports have appeared describing the atomic absorption determination of copper in dissolved steels to which varjous reagents have been added to reduce interelement effects (62,151,204,464). In several other cases reported, solvent extraction with propylene carbonate (643) and an electrographic technique for surface analysis (622) have been used for sample pretreatment. Ores and agglomerates (420) have also been analyzed by atomic absorption following acid dissolution. A novel technique for assay of copper by an atomic absorption method for shipboard use for manganese-nodule analysis that does not require weighing the sample has appeared (414). Emission Spectroscopy. Numerous reports have been given of the application of direct-reading instruments to the analysis of steels (118,492,546,570,670),cast irons (249,4501, and ferroalloys (245). Luminescent dlscharge (59) and laser excitation (598) have been described for copper in steel. The report of an extraction-spectrographic method for micro impurities in steels with a detection limit of 10-7 to lo-%? has
been published (395). Temporal scanning of arc and spark spectra reportedly increase the precision of copper determinations in steel (478). X-ray Fluorescence. High-purity irons (261, 262), low alloys ( 7 ) ,stainless steels (710), cast irons (552), and manganese nodules (536) have all been analyzed for copper by x-ray fluorescence techniques. Small samples of steel, 95% recovery is then dissolved and determined b atomic absor tion. Detection limits of 0.02-2 Fglg with a refative standartdeviation of 5% are claimed for Bi, Cd, Ga, In, P b , T1, and Zn. A critical review of atomic fluorescence for the analysis of aluminum alloys using multichannel instrumentation was published by Browner (32). New methods for preparing metallic aluminum samples for atomic absorption were reported by Ghiglione et al. (92) and Human et al. (117).Ghiglione prepared a colloidal suspension by means of a water immersed spark using a new type of disperser. These dispersions show the same behavior as true solutions in atomic absorption and are stable for several hours. Human used a conventional high-voltage spark as a sampling-nebulizing device for metal samples. Gas passing through the spark chamber transports the metal particles into the flame. The technique was also applied t o atomic fluorescence and inductively coupled plasma emission spectrometry. The use of H3P04to dissolve difficultly soluble metal oxides for analysis by atomic absorption was reported by Hofton and Baines (113) and by Tamnev et al. (258). Hofton and Baines used the technique to dissolve MgO and Tamnev determined Na and Mg in P-Al203. Optical Emission Spectroscopy. Emission spectroscopy continues to be one of the more important analytical techniques in the light metal industries. Several papers of a theoretical nature were published during the past two years. Stachova (250) studied the effect of alloying components, the discharge gas, and the state of the electrode surface on the analysis of A1 alloys in a high-voltage spark discharge. Kazennova and Taganov (132) also studied the effect of structure and examined the feasibility of decreasing its effect on the spark spectra of A1 alloys by etching. Studies showing the advantages of an Ar atmosphere for sparking aluminum samples were reported by Strasheim and Blum (252) and by Slickers et al. (247). Both articles claimed better homogeneity in the microfusion area of the sample and, therefore, a marked decrease in interelement effects resulted. Strasheim and Blum used a scanning electron microscope and an energy dispersive x-ray analyzer in their investigations. Kubota and Ishida (151) found that a 20 to 1volume mixture of Ar and 0 2 improved the spectrochemical sensitivity for determining Mg and Zn in A1 alloys using a laser microprobe with auxiliary spark excitation. Berenshtein et al. (22) described a mathematical method for determining the optimum composition of spectrographic buffers for determining Be in carbonate and silicate minerals by comparing calibration curves. Marinkovic et al. (168) developed a gas stabilized arc for determining metals in solution. An accuracy and reproducibility study of spectrometric methods for high purity A1 and A1 alloys was reported by
