Cracking in High-strength Steel Weldments
Cracking in High-strength Steel Weldments

Author: P. A. Kammer

Publisher:

Published: 1964

Total Pages: 132

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Weldment cracking is a broad complex field. Even if one considers only cracking of steel weldments, the problems range from cracking at temperatures near the solidus during welding to cracking at room temperature days, weeks, or months after welding is completed. Numerous reports of investigations in this field are contained in the published and unpublished literature. However, most of these reports cover only a particular problem in a specific area of the broad field of weldment cracking. This review attempts to cover the major aspects of the entire field of weldment cracking. Necessarily, the review is for the most part general, only being specific in a few instances to illustrate a point. (Author).

The Effects of High Pressure, High Temperature Hydrogen on Steel
The Effects of High Pressure, High Temperature Hydrogen on Steel

Author: Ellis E. Fletcher

Publisher:

Published: 1964

Total Pages: 82

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This report deals with the deleterious effects of hydrogen gas on steel at elevated temperatures and/or pressures. Hydrogen attack on steels is manifest as decarburization, intergranular fissuring, or blistering. These conditions result in lowered tensile strength, ductility, and impact strength. The reaction of hydrogen with iron carbide to form methane is probably the most important chemical reaction involved in the attack on steel by hydrogen. Attack of steel at elevated temperatures and pressures is limited or prevented by the following measures: (1) use of steel alloyed with strong carbide-forming elements, (2) use of liners of resistant alloy steels, and (3) substitution of resistant nonferrous alloys.

The Application of High Pressure in Metal-deformation Processing
The Application of High Pressure in Metal-deformation Processing

Author: F. W. Boulger

Publisher:

Published: 1964

Total Pages: 82

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On October 3, 1963, a symposium was sponsored by the Bureau of Naval Weapons, Metalworking Processes and Equipment Program, on the application of high pressure in metal-deformation processing. Past research has shown that superimposed hydrostatic pressure can significantly increase the ductility at fracture of various materials. These observations have stimulated considerable interest in applying this hydrostatic-pressure effect to metal deformation processing, where it was anticipated that improved ductility and fabricability of brittle materials could be realized. Hydrostatic extrusion and hydrodynamic compressive forging were two such fabrication techniques discussed at the symposium, and preliminary results were found to be encouraging. Another fabrication process that will be investigated in the near future is sheet drawing, where the effect of superimposed pressure improves the ductility to fracture, it was noted that pressure cycling did not improve either the strength or ductility of steels containing various amounts of carbon. In addition to the mechanical-property effects, hydrostatic pressure has been found to affect measurably, numerous metallurgical properties of metals and alloys. (Author).

Vacuum Degassing in the Production of Premium-quality Steels
Vacuum Degassing in the Production of Premium-quality Steels

Author: P. J. O'Reilly

Publisher:

Published: 1964

Total Pages: 138

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This report gives the experiences of several steel producers and consumers with vacuum degassing as a melting practice in the manufacture of high-strength steels for critical applications. The parameters involved in determining the effects of melting practice on mechanical properties are outlined. Pertinent melting processes are described and evaluated qualitatively. In presenting the data, vacuum degassing is compared with other melting practices such as conventional air melting and consumable-electrode vacuum-arc remelting (CEVAR). Generally, there is a trend indicating that vacuum degassing is being used in some production applications instead of air-melted or CEVAR material. In terms of higher and more uniform transverse tensile properties and impact strength, longer fatigue life, and improved cleanliness, the CEVAR alloys were the best. Vacuum degassing by any of the various methods resulted in an improvement in properties of air-melted alloys. In some instances it appeared that the quality of CEVAR alloys could be approached when stream degassing or D-H (Dortmund-Horder) treatment was applied to air melts. Recommendations are given for additional investigations on the effects of melting practice on mechanical properties of premium-quality steels. (Author).

The Mechanical Properties of the 18 Per Cent Nickel Maraging Steels
The Mechanical Properties of the 18 Per Cent Nickel Maraging Steels

Author: J. E. Campbell

Publisher:

Published: 1964

Total Pages: 136

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Since the combination of tensile properties and toughness that can be obtained with the maraging steels is higher than can be achieved with other steels by simple heat treatments, there is considerable interest in using the maraging steels for critical components such as rocket motor cases, pressure vessels, and aircraft forgings. This report includes information on the tensile, compressive, shear, bearing, dynamic modulus, impact, bend, fatigue, creep, and rupture properties of the 18 per cent nickel maraging steels and on the effect of temperature on these properties. Data for the properties of sheet, bar, and forgings, as well as data illustrating the effect of cold rolling, variation in the heat treatment, and elevated-temperature exposure also are presented. Data on the effect of specimen orientation, which are also included, indicate that the ductility and toughness of specimens designed to evaluate the properties in the short transverse direction are somewhat lower than in the other directions. The high strength and toughness that can be obtained in the 18 per cent nickel maraging steels make them attractive for certain critical applications that require these properties. The fabrication characteristics, weldability, and simple heat treatment are other advantages of these steels. (Author).

The Application of Ultrasonic Energy in the Deformation of Metals
The Application of Ultrasonic Energy in the Deformation of Metals

Author: Alan R. Rosenfield

Publisher:

Published: 1963

Total Pages: 88

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On June 21 a symposium was sponsored by the Bureau of Naval Weapons on the application of ultrasonic energy in the deformation of metals. At this session, a number of investigators actively working in the field reported informally on the results of their research. The reports revealed that the results achieved by incorporating ultrasonic transducers into conventional metalforming and-cutting operations are sufficiently promising that the technique merits further attention. Data are available to indicate that application of ultrasonic vibrations during metal working can increase speeds, lower forces, and improve surface finishes. All of these results have been obtained without any observed difference in properties between ultrasonically and conventionally fabricated parts. (Author).

Properties of Coated Refractory Metals
Properties of Coated Refractory Metals

Author: W. A. Gibeaut

Publisher:

Published: 1964

Total Pages: 104

ISBN-13:

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This report summarizes the information generated since the middle of 1961 on the chemical, physical, and mechanical properties of refractory metals that are coated with oxidation-resistant coatings of advanced-experimental or commercial status. It is a supplement to DMIC Report 162, Coatings for the Protection of Refractory Metals from Oxidation, dated November 24, 1961. Recent data on specific silicide- and aluminide- type coatings for columbium, molybdenum, tantalum, and tungsten and their alloys reflect general advances in coating quality and performance, understanding of the behavior of coated systems, and more complete realization of the problems associated with the use of coated hardware.