Fig. 30 Fatigue data (a) showing sequence effects for notched-specimen and smooth- specimen simulations (2024-T4 aluminum, K f = 2.0). Load histories A and B have a similar cyclic load pattern (dS 2 ) but have slightly different initial transients (∆S 1 ) with either (b) a tensile leading edge (first stress peak at +∆S 1 /2) or (c) a compressive leading edge (first stress peak at -∆S 1 /2). The sequence effect on fatigue life (a) becomes more pronounced as ∆S 2 smaller. Source: Ref 21 Ultimately, the fatigue analyst will be required to include and correlate a number of material, shape, processing, and load factors in order to identify the critical locations within a part and to describe the local stress-strain response at those critical locations. The ability to anticipate pertinent factors will greatly affect the final accuracy of the life prediction. Load data gathering is one remaining topic that must be included in any discussion of fatigue. Reference 21 discusses three load histories, suspension, transmission, and bracket vibration, that typify loads found in the ground vehicle industry. Additionally, there are vastly different histories unique to other industries, like the so-called ground-air-ground cycle in aeronautics. Without the ability to completely and accurately characterize anticipated and, occasionally, unanticipated customer use and resultant loads, the analyst will not be able to predict accurately the suitability of a new or revised design. The last several years have seen a major change in the ability to gather customer or simulated customer load data. Testing methods have progressed from bulky, multichannel analogue tape recorders (where it took days or weeks before results were available) through portable frequency-modulated telemetry packages (where analysis could be performed immediately at a remote site) to hand-held packages capable of data acquisition and analysis on board the test vehicle in real time. Microelectronics is further reducing size and improving reliability to the point that data can be gathered from within small, complex, moving, hostile assemblies, such as engines. References cited in this section 6. R.C. Juvinall, Engineering Considerations of Stress, Strain and Strength, McGraw-Hill, 1967 7. N.E. D owling, W.R. Brose, and W.K. Wilson, Notched Member Fatigue Life Predictions by the Local Strain Approach, in Fatigue Under Complex Loading: Analyses and Experiments, R.M. Wetzel, Ed., Society of Automotive Engineers, 1977 8. J.A. Graham, Ed., Fatigue Design Handbook, Society of Automotive Engineers, 1968 9. H.O. Fuchs and R.I. Stephens, Metal Fatigue in Engineering, John Wiley & Sons, 1980 10. Special Publication P-109, in Proceedings of the SAE Fatigue Conference, Society of Automotive Engineers, 1982 11. R.C. Rice, Ed., Fatigue Design Handbook, 2nd ed., Society of Automotive Engineers, 1988 12. J.T. Ransom, Trans. ASM, Vol 46, 1954, p 1254-1269 13. "Fatigue Properties," Technical Report, SAE J1099, Society of Automotive Engineers, 1977 14. P.H. Wirsching and J.E. Kempert, A Fresh Look at Fatigue, Mach. Des., Vol 48 (No. 12), 1976, p 120-123 15. L.E. Tucker, S.D. Downing, and L. Camillo, Accuracy of Simplified Fatigue Prediction Methods, in Fatigue Under Complex Loading: Analyses and Experiments, R. M. Wetzel, Ed., Society of Automotive Engineers, 1977 16. R.E. Peterson, Stress Concentration Design Factors, John Wiley & Sons, 1974 17. R.J. Roark, Formulas for Stress and Strain, 4th ed., McGraw-Hill, 1965 18. J.M. Potter, Spectrum Fatigue Life Predi ctions for Typical Automotive Load Histories and Materials Using the Sequence Accountable Fatigue Analysis, in Fatigue Under Complex Loading: Analyses and Experiments, R.M. Wetzel, Ed., Society of Automotive Engineers, 1977 19. D.V. Nelson and H.O. Fuchs, Predictions of Cumulative Fatigue Damage Using Condensed Load Histories, in Fatigue Under Complex Loading: Analyses and Experiments, R.M. Wetzel, Ed., Society of Automotive Engineers, 1977 20. S.D. Downing and D.F. Socie, Simple Rainflow Counting Algorithms, Int. J. Fatigue, Jan 1981 21. D.F. Socie, "Fatigue Life Estimation Techniques," Technical Report 145, Electro General Corporation Fatigue Resistance of Steels Bruce Boardman, Deere and Company, Technical Center References 1. R.W. Hertzberg, Deformation and Fracture Mechanics of Engineering Materials, John Wiley & Sons, 1976 2. D.J. Wulpi, Understanding How Components Fail, American Society for Metals, 1985 3. Fatigue and Microstructure, in Proceeding of the ASM Materials Science Seminar, American Society for Metals, 1979 4. Metallic Materials and Elements for Aerospace Vehicle Structures, MIL-HDBK-5B, Military Standardization Handbook,, U.S. Department of Defense, 1987 5. Metallic Materials and Elements for Aerospace Vehicle Structures, Vol 1, MIL-HDBK-5B, Military Standardization Handbook, U.S. Department of Defense, Sept 1971, p 2-29 6. R.C. Juvinall, Engineering Considerations of Stress, Strain and Strength, McGraw-Hill, 1967 7. N.E. Dowling, W.R. Brose, and W.K. Wilson, Notched Member Fatig ue Life Predictions by the Local Strain Approach, in Fatigue Under Complex Loading: Analyses and Experiments, R.M. Wetzel, Ed., Society of Automotive Engineers, 1977 8. J.A. Graham, Ed., Fatigue Design Handbook, Society of Automotive Engineers, 1968 9. H.O. Fuchs and R.I. Stephens, Metal Fatigue in Engineering, John Wiley & Sons, 1980 10. Special Publication P-109, in Proceedings of the SAE Fatigue Conference, Society of Automotive Engineers, 1982 11. R.C. Rice, Ed., Fatigue Design Handbook, 2nd ed., Society of Automotive Engineers, 1988 12. J.T. Ransom, Trans. ASM, Vol 46, 1954, p 1254-1269 13. "Fatigue Properties," Technical Report, SAE J1099, Society of Automotive Engineers, 1977 14. P.H. Wirsching and J.E. Kempert, A Fresh Look at Fatigue, Mach. Des., Vol 48 (No. 12), 1976, p 120-123 15. L.E. Tucker, S.D. Downing, and L. Camillo, Accuracy of Simplified Fatigue Prediction Methods, in Fatigue Under Complex Loading: Analyses and Experiments, R.M. Wetzel, Ed., Society of Automotive Engineers, 1977 16. R.E. Peterson, Stress Concentration Design Factors, John Wiley & Sons, 1974 17. R.J. Roark, Formulas for Stress and Strain, 4th ed., McGraw-Hill, 1965 18. J.M. Potter, Spectrum Fatigue Life Predictions for Typical Automotive Load Histories and Material s Using the Sequence Accountable Fatigue Analysis, in Fatigue Under Complex Loading: Analyses and Experiments, R.M. Wetzel, Ed., Society of Automotive Engineers, 1977 19. D.V. Nelson and H.O. Fuchs, Predictions of Cumulative Fatigue Damage Using Condensed Load Histories, in Fatigue Under Complex Loading: Analyses and Experiments, R.M. Wetzel, Ed., Society of Automotive Engineers, 1977 20. S.D. Downing and D.F. Socie, Simple Rainflow Counting Algorithms, Int. J. Fatigue, Jan 1981 21. D.F. Socie, "Fatigue Life Estimation Techniques," Technical Report 145, Electro General Corporation Embrittlement of Steels George F. Vander Voort, Carpenter Technology Corporation Introduction IRON-BASE ALLOYS are susceptible to a number of embrittlement phenomena. Some of these affect a wide range of compositions, while others are specific to a rather narrow range of compositions. These problems promote brittle service failures that may be catastrophic in nature or may reduce the useful service life of a component. This article reviews these embrittlement problems and presents examples of their influence on mechanical properties. These problems arise from compositional, processing, or service conditions, or combinations of these three conditions. If the embrittlement occurs during processing at the mill, it may be detected during routine testing depending on the degree of embrittlement and the nature of the testing program. The steelmaker is generally aware of the potential problems that particular grades are susceptible to and will check the various well-known parameters that can promote such problems. This starts with an examination of chemical composition, such as gas contents or impurity elements that are known to cause problems. For example, in the melting of ingots for pressure vessels or rotors where temper embrittlement is a potential problem, the selection of scrap for electric furnace melting is based on the scrap impurity level, and every effort is made to keep residual levels of phosphorus, antimony, tin, and arsenic as low as possible. Subsequent impact testing of coupons from the forgings is used to verify the initial toughness. Such information is compared to specification requirements and historical data base information to maintain quality. Special melting practices, such as vacuum carbon deoxidation, have also been adopted for critical composition control. Furthermore, additional knowledge is obtained by surveillance testing and by postmortems on retired forgings. However, not all potential problems can be detected, or prevented, at the mill. Some arise from handling or fabrication problems. For example, low-carbon sheet steels that are not aluminum killed are roller leveled at the mill prior to shipment to suppress the yield point and prevent strain-age embrittlement. However, if this steel is not formed within a certain time period, the yield point will return, and discontinuous yielding may occur when the sheet is cold formed, resulting in cosmetically damaging Lüders bands on the product. For this and other fabrication problems, postfabrication inspection and testing programs must be properly planned and executed. Service and environmental conditions can also cause a number of embrittlement problems. Engineers working with steel components that are susceptible to such operating-induced problems must be aware of the potential problems and must establish regular inspection programs to detect problems before they become critical. An excellent example of such programs is the on-site, in situ examination of steam piping in electric power generation plants; these examinations make extensive use of field metallography and replication to assess creep damage and predict remnant life. Embrittlement of Steels George F. Vander Voort, Carpenter Technology Corporation Embrittlement of Iron Before discussing the embrittlement of steels, this article will first examine the embrittlement of iron because the number of such studies are few compared to those for steels. Grain-boundary segregation of elements such as oxygen, sulfur, phosphorus, selenium, and tellurium is known to produce intergranular brittle fractures in iron at low temperatures. Studies of the effects of such impurities in pure iron have been greatly aided by the development of Auger electron spectroscopy (AES). Intercrystalline fractures in iron at low temperatures occur when the carbon content is low. It has been assumed that the absence of carbon is more important than the presence of embrittling grain-boundary impurities. However, impurities must be present, and the role of carbon appears to be one of a competitor for grain-boundary sites when such impurities are present. Oxygen. A study of the toughness of iron-oxygen alloys found that intergranular embrittlement and a rise in impact transition temperature in iron were produced by oxygen levels of 30 ppm or more (Ref 1). Figure 1 shows the Charpy V- notch impact transition curves from this study for a series of iron-oxygen alloys with increasing oxygen contents (from 10 to 2700 ppm). However, the sulfur levels of the heats were rather high, from 30 to 54 ppm for the alloys shown in Fig. 1, except for the 0.011% O heat, which had 16 ppm S. Because this work was conducted long before the introduction of AES, the true nature of the embrittling grain-boundary element(s) is open to question. Fig. 1 Charpy V-notch impact energy curves for iron-oxygen alloys with varying oxygen content. Source: Ref 1 Work on high-purity iron found intergranular brittleness at low test temperatures when specimens were quenched from temperatures where carbon was in solution (Ref 2, 3). It was believed that this brittleness was due to oxygen. Lowering the quench temperature reduced the embrittlement. Titanium additions were not found to be helpful in reducing the intergranular embrittlement. Reference 4 reviews the study from Ref 3 and reports on similar work performed in France that found that sulfur, not oxygen, was the cause of the embrittlement. Tests were done using electrolytic iron containing 35 ppm S and a purified iron containing less than 1 ppm S; each contained 2000 ppm O and varying carbon contents. The purified iron was found to be much less brittle than the electrolytic iron (Fig. 2). At 10 ppm C, the purified iron was free of intergranular fracture; the electrolytic iron fractured intergranularly below the ductile-to-brittle transition temperature (DBTT). Fig. 2 Transition temperature, T t , versus carbon content for two different high- purity irons, each containing 2000 ppm O. Source: Ref 4 Reference 5, on the other hand, shows Auger analysis of intergranular fractures of the pure iron specimen from Ref 2 that contained 60 ppm S. Sulfur was not detected on the intergranular fracture, while carbon, nitrogen, and oxygen were. The authors did state that the oxygen peak could possibly be due to oxygen contamination after fracture in the high vacuum used for Auger work (fracture made inside the evacuated chamber). It has been demonstrated that large variations in oxygen content have no influence on the brittleness of iron (Ref 6). The Charpy U-notch transition temperatures of electrolytic iron and high-purity iron with varying oxygen and carbon contents were determined, as in Ref 4. Figure 3 shows that the DBTTs for these two irons were constant over a wide range of oxygen contents (1 to 2000 ppm). The DBTT of the electrolytic iron (210 °C, or 410 °F) was consistently much higher than that of the high-purity iron (20 °C, or 70 °F). Also, fractures for the electrolytic iron specimens in the brittle range were fully intergranular, whereas those for the high-purity iron were by cleavage. Carbon and sulfur contents were 30 and 35 ppm, respectively, for the electrolytic iron and 10 and less than 3 ppm, respectively, for the high-purity iron. Manganese contents were 12 ppm for the electrolytic iron and less than 0.5 ppm for the high-purity iron, too little to tie up the sulfur completely in the electrolytic iron. Figure 4 shows the results when carbon and oxygen were both varied. When the carbon level was increased to 30 ppm, there was a large improvement in the DBTT, irrespective of the oxygen level. This study also demonstrated that the addition of elements that form sulfide precipitates improved the DBTT. Fig. 3 Ductile-to-brittle transition temperatures (from tests using Charpy U- notch specimens) as a function of oxygen content for a decarburized electrolytic iron and a high-purity iron with 10 ppm C. Source: Ref 6 Fig. 4 Ductile-to-brittle transition temperatures of high-purity iron as a function of carbon content and oxygen content. Source: Ref 6 On the other hand, a study using irons with less than 2 ppm S and 0.5 ppm C and Auger analysis demonstrated oxygen grain-boundary enrichment of intergranular fractures broken by impact within the AES chamber (Ref 7). Segregation of elements such as sulfur, phosphorus, and nitrogen was not observed on the fracture, but oxygen was detected. For a specimen with a bulk oxygen content of 430 at. ppm, there were two monolayers of oxygen at the intergranular fracture surface. Carbon was not present at the fracture surface, consistent with the very low bulk carbon content. Another specimen with 235 at. ppm O exhibited about 15% cleavage fracture, along with areas that were predominantly intergranular. The study found that for the material with higher oxygen content, quenching specimens from temperatures of 1103 and 1123 °C (2017 and 2053 °F), near the solubility limit, gave predominantly intergranular low-temperature fractures. When the temperature was lowered from 973 to 773 °C (1783 to 1423 °F), below the solubility limit, the amount of intergranular fracture decreased. Also, if the specimen was slow cooled from temperatures near the solubility limit, low-temperature fractures were fully by cleavage. Therefore, the study concluded that intergranular brittle fracture of iron was due to the oxygen in solution. Sulfur. The embrittlement of iron by sulfur has been demonstrated by several authors. Prior to Auger analysis, such results were assumed, but without direct proof. Auger work has, indeed, confirmed that sulfur is a potent embrittler of iron, even at bulk levels as low as 10 ppm. Furthermore, the displacement of sulfur on the grain boundaries when carbon is added has been proved by Auger analysis. Low-temperature impact tests performed on three heats of relatively pure iron obtained intergranular fractures, depending on the heat treatment used (Ref. 8). Sulfur contents ranged from 14 to 100 ppm, carbon contents from less than 10 to 70 ppm, and oxygen contents from 8 to 420 ppm. Auger analysis revealed heavy segregation of sulfur to the grain boundaries. No clear evidence of oxygen on the intergranular fractures was obtained. Other studies have shown the detrimental influence of small sulfur additions (Ref 9, 10). Figure 5, from these studies, shows the DBTT as a function of bulk sulfur content ( ≤ 60 ppm) and the beneficial influence of carbon additions ( ≤ 10 to 30 ppm) for iron containing 2000 ppm O. For less than or equal to 10 ppm C, the transition temperature increased from 0 to over 600 °C (30 to >1110 °F) with increasing sulfur content. However, with 25 of 30 ppm C, the influence of sulfur was small. Also demonstrated was the scavenging influence of a 0.5% Al addition, which suppressed embrittlement (constant DBTT) for the full range of sulfur ( ≤ 60 ppm) tested. Fig. 5 Influence of sulfur on the transition temperature of purified iron containing 2000 ppm O, and the influence of carbon content on sulfur embrittlement. Increasing carbon content has the bene ficial effect of decreasing sulfur embrittlement. Source: Ref 9, 10 Selenium and tellurium are similar to sulfur and are potential embrittlers of pure iron. One study (Ref 10) showed that they do cause embrittlement, but to a lesser degree than sulfur (Fig. 6). In this work, the carbon content was less than 10 ppm, and 2000 ppm O was present. Although selenium and tellurium had less influence on the DBTT, these two elements reduced the absorbed energy values much more than did sulfur. Therefore, in terms of impact energy, the elements can be placed in order of increasing influence as follows: sulfur, selenium, and tellurium. Others have also reported the embrittlement of Fe-0.04% C by 0.02% Te (Ref 11). Fig. 6 Influence of sulfur, tellurium, and selenium on the transition temperature of purified iron containing up to 10 ppm carbon and approximately 2000 ppm O. Source: Ref 10 Other Impurity Elements. Phosphorus has also been reported to embrittle pure iron (Ref 12, 13). However, both of these studies used materials with a significant sulfur content, and they were performed prior to the development of Auger analysis. However, radioactive tracer analysis demonstrated the segregation of phosphorus at the grain boundaries of an Fe-0.09% P alloy (Ref 12). Phosphorus was reported to be 50 times as prevalent at the grain boundaries as in the grain interiors. Phosphorus does substantially increase the strength of ferrite. Again, the addition of carbon was shown to reduce the influence of phosphorus on embrittlement. Researchers have also studied phosphorus segregation in pure iron (Ref 14). Again, the specimens contained a significant amount of sulfur, but mechanical properties were not determined. However, a small amount of manganese was present that should precipitate the sulfur as a sulfide. The carbon content was reduced to below 10 ppm. Specimens were austenitized, water quenched, tempered at 850 °C (1560 °F) for 1 h, and then furnace cooled to the aging temperature. Specimens were fractured within the Auger chamber. Phosphorus was observed on the surface of intergranular fractures, but not on cleavage fractures. Auger analysis showed that the amount of phosphorus on the intergranular fractures increased with bulk phosphorus content. Also, as the aging temperature decreased, the grain-boundary phosphorus content increased, and the fracture became more intergranular. When carbon was added ( ≤ 80 ppm), the grain-boundary phosphorus concentration decreased. A deep-drawing steel containing 7 ppm C, 310 ppm P, and 0.36% Mn fractured intergranularly in the drawing direction, and phosphorus was detected on the grain boundaries (Ref 14). Similar steels with 14 ppm C, 80 ppm P, and 0.38% Mn did not fracture during deep drawing. A study of the embrittlement of iron by phosphorus, phosphorus and sulfur, and antimony and sulfur demonstrated that the embrittlement was different from that of temper embrittlement in that it was not reversible (Ref 15). Segregation occurred at all temperatures in ferrite but was negligible or limited in austenite. Quenching from the austenite region produced specimens that fractured by cleavage. When quenched from the two-phase region, fractures did exhibit phosphorus at the grain boundaries. When an Fe-0.2P alloy was furnace cooled from the austenite region, the fracture surface exhibited a layer of nearly pure phosphorus at the grain boundary with a thickness of 1 to 1.5 nm (10 to 15 A o ). The ternary alloys containing sulfur exhibited DBTTs of about 350 °C (660 °F). The study concluded that sulfur, even at much lower concentrations than phosphorus, is a more potent embrittler of iron. Metalloids such as phosphorus, arsenic, antimony, and tin do not produce embrittlement of pure iron containing minor amounts of carbon in the same manner as sulfur, although they do in alloy steels (Ref 16). It has been demonstrated that such elements produce embrittlement of carbide/ferrite and surrounding ferrite/ferrite interfaces (Ref 17). This appears to be a nonequilibrium segregation problem, however. The influence of tin on high-purity iron and low-carbon steel has been examined (Ref 18). Detailed chemical analyses of the pure iron specimens used were not given in the study, although it was stated that the base metal had a carbon content of 20 ppm and an oxygen content of 400 ppm. The addition of 0.5% Sn to the pure iron reduced the impact strength in the ductile region to such a degree that the absorbed energy was constant up to 70 °C (160 °F). Specimens water quenched from 650 °C (1200 °F) exhibited impact results similar to those of tin-free pure iron, while slowly cooled specimens were embrittled. The addition of 0.15% C to the Fe-0.5Sn alloy did reduce the embrittling influence of tin, and the alloy had better toughness than the pure iron specimen when water quenched from 650 °C (1200 °F). The addition of 0.15% P to the Fe-0.5Sn-0.15C alloy raised the DBTT about 20 °C (36 °F) and lowered the upper-shelf energy when water quenched from 650 °C (1200 °F). The examination of fractured specimens showed a changed from transgranular cleavage to intergranular fracture as the tin content increased, particularly for the slowly cooled specimens. This survey of the influence of impurities on the embrittlement of pure iron has demonstrated that the design of experiments and the interpretation of results are difficult. Many of the early studies did not recognize the significance of relatively minor amounts of sulfur in the high-purity irons used. It is clear that Auger analysis is required to determine the embrittling species. When sulfur is present in the absence of sulfide-forming elements, it has a dominating influence on properties and behavior. The addition of carbon above about 10 ppm will reduce or eliminate embrittlement effects. References cited in this section 1. W.P. Rees and B.E. Hopkins, Intergranular Brittleness in Iron-Oxygen Alloys, J. Iron Steel Inst., Vol 172, Dec 1952, p 403-409 2. C.J. McMahon, Jr., Intergranular Brittleness in Iron, Acta Metall., Vol 14, July 1966, p 839-845 3. J.R. Rellick and C.J. McMahon, Jr., The Elimination of Oxygen-Induced Intergranular Br ittleness in Iron by Addition of Scavengers, Metall. Trans., Vol 1, April 1970, p 929-937 4. P. Jolly, Discussion of "The Elimination of Oxygen- Induced Intergranular Brittleness in Iron by Addition of Scavengers," Metall. Trans., Vol 2, Jan 1971, p 341-342 5. J.R. Rellick et al., Further Information on Oxygen Induced Intergranular Brittleness in Iron, Metall. Trans., Vol 2, Jan 1971, p 342-343 6. C. Pichard et al., The Influence of Oxygen and Sulfur on the Intergranular Brittleness of Iron, Metall. Trans. A, Vol 7A, Dec 1976, p 1811-1815 7. A. Kumar and V. Raman, Low Temperature Intergranular Brittleness of Iron, Acta Metall., Vol 29, 1981, p 1131-1139 8. B.D. Powell et al., A Study of Intergranular Fracture in Iron Using Auger Spectroscopy, Metall. Trans., Vol 4, Oct 1973, p 2357-2361 9. P. Jolly and C. Goux, Influence of Certain Impurities on Intercrystalline Embrittlement of Iron, Mem. Sci. Rev. Met., Vol 66 (No. 9), 1969, p 605-617 10. C. Pichard et al., Influence of Sulfur Type Metalloid Impuritie s on the Intercrystalline Embrittlement of Pure Iron, Mem. Sci. Rev. Met., Vol 70 (No. 1), 1973, p 13-22 11. J.R. Rellick et al., The effect of Telurium on Intergranular Cohesion in Iron, Metall. Trans., Vol 2, May 1971, p 1492-1494 [...]... Boundaries of Fe-P, Fe-C-P, Fe-Cr-P, and Fe-Cr-C-P Alloys, Met Sci., Vol 15, Sept 1981, p 40 1- 408 15 P.V Ramasubramanian and D.F Stein, An Investigation of Grain-Boundary Embrittlement in Fe-P, Fe-P-S, and Fe-Sb-S Alloys, Metall Trans., Vol 4, July 1973, p 173 5-1 742 16 C.J McMahon, Jr., Strength of Grain Boundaries in Iron-Base Alloys, in Grain Boundaries in Engineering Materials, Claitor, 1975, p 52 5-5 52 17...12 M.C Inman and H.R Tipler, Grain-Boundary Segregation of Phosphorus in an Iron-Phosphorus Alloy and the Effect Upon Mechanical Properties, Acta Metall., Vol 6, Feb 1958, p 7 3-8 4 13 B.E Hopkins and H.R Tipler, The Effect of Phosphorus on the Tensile and Notch-Impact Properties of High-Purity Iron and Iron-Carbon Alloys, J Iron Steel Inst., Vol 188, March 1958, p 21 8-2 37 14 H Erhart and H.J Grabke,... LowAlloy Steels, Met, Technol., Vol 2, Sept 1975, p 41 6-4 21 73 R.C Andrew et al., Overheating in Low-Sulphur Steels, J Australasian Inst Met., Vol 21, June-Sept 1976, p 12 6-1 31 74 R.C Andrew and G.M Weston, The Effect of Overheating on the Toughness of Low Sulphur ESR Steels, J Aust Inst Met., Vol 22, Sept-Dec 1972, p 17 1-1 76 75 R.C Andrew and G.M Weston, The Effect of the Interaction Between Overheating and. .. tin, and antimony to the nickelchromium-carbon, nickel-carbon, and chromium-carbon steels The nonembrittled toughnesses of the nickel-chromiumcarbon-phosphorus and chromium-carbon-phosphorus alloys were poorer than those of the other alloys shown, probably because of the segregation of phosphorus in austenite Phosphorus also embrittled the chromium-carbon-phosphorus alloy much more than the nickel-carbon-phosphorus... Vol 205, Nov 1967, p 115 6-1 160 60 W.J.M Salter, Effect of Mutual Additions of Tin and Nickel on the Solubility and Surface Energy of Copper in Mild Steel, J Iron Steel Inst., Vol 207, Dec 1969, p 161 9-1 623 61 H.J Kerr and F Eberle, Graphitization of Low-Carbon and Low-Carbon-Molybdenum Steels, Trans ASME, Vol 67, 1945, p 1-4 6 62 S.L Hoyt et al., Summary Report on the Joint E.E.I.-A.E.I.C Investigation... range, generally 300 to 600 °C (570 to 111 0 °F) for low-alloy steels This treatment causes a decrease in toughness as determined with Charpy V-notch impact specimens (Ref 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110 , 111 , 112 , 113 , 114 ) It is a particular problem for heavy-section components, such as pressure vessels and turbine rotors, that are slowly... Intermetallic Phases and Non-Metallic Inclusions Upon the Ductility and Fracture Behavior of Some Alloy Steels, in Effect of Second-Phase Particles on the Mechanical Properties of Steel, Iron and Steel Institute, 1971, p 9 5-1 00 71 T.J Baker and R Johnson, Overheating and Fracture Toughness, J Iron Steel Inst., Vol 211, Nov 1973, p 78 3-7 91 72 D.R Glue et al., Effect of Composition and Thermal Treatment... 1970, p 86 1-8 68 28 G Lagerberg and B.S Lement, Morphological and Phase Changes During Quench-Aging of Ferrite Containing Carbon and Nitrogen, Trans ASM, Vol 50, 1958, p 14 1-1 62 29 J.D Baird, Strain Aging of Steel A Critical Review, Iron Steel, Vol 36, 1963, p 18 6-1 92, 32 6-3 34, 368374, 40 0-4 05, and 45 0-4 57 30 J.D Baird, The Effects of Strain-Aging Due to Interstitial Solutes on the Mechanical Properties. .. °F) on the tensile properties of an Fe-0.03C rimming alloy (a) Tensile and yield strength (b) Elongation and reduction in area Source: Ref 25 Iron-Nitrogen and Iron-Carbon Alloys For iron-nitrogen alloys, two types of nitrides can precipitate during quench aging: • • Face-centered cubic (fcc) Fe4N platelets form at high temperatures and generally are found at grain boundaries Body-centered cubic (bcc)... 480, and 650 °C (75, 450, 900, and 1200 °F) for various lengths of time ( ≤ 25,000 h at 25 and 230 °C, or 75 and 450 °F; ≤ 10 h at 480 °C, or 900 °F; and 2 h at 650 °C, or 1200 °F) Hardness, tensile properties, and impact properties (half-width Charpy V-notch specimens) were determined at different aging times Figure 10 shows the impact test results for steels A, B, and C strained 10% in tension and . 14. H. Erhart and H.J. Grabke, Equilibrium Segregation of Phosphorus at Grain Boundaries of Fe-P, Fe-C- P, Fe-Cr-P, and Fe-Cr-C-P Alloys, Met. Sci., Vol 15, Sept 1981, p 40 1- 408 15. P.V 15. P.V. Ramasubramanian and D.F. Stein, An Investigation of Grain-Boundary Embrittlement in Fe-P, Fe-P- S, and Fe-Sb-S Alloys, Metall. Trans., Vol 4, July 1973, p 173 5-1 742 16. C.J. McMahon,. tensile properties of an Fe-0.03C rimm ing alloy. (a) Tensile and yield strength. (b) Elongation and reduction in area. Source: Ref 25 Iron-Nitrogen and Iron-Carbon Alloys. For iron-nitrogen alloys,