New Developments In Welding Steels With Yield Strengths Greater Than 150 000 Psi

The report summarizes the advancements made in the development and welding of steels possessing yield strengths greater than 150,000 psi. Steels discussed include the medium carbon, low-alloy martensitic steels; low carbon alloy martensites; and nickel maraging steels. Almost all programs which have the objective of developing high-strength steels have an equally important phase concerned with filler metal development. Filler metals are also discussed. The new welding processes discussed are Narrow-Gap welding, electron-beam welding, plasma-arc welding, high-frequency resistance welding, electroslag welding, laser welding, and interrupted-arc (dip trasfer) MIG welding. (Author).

Recent studies of the developments in welding steels with yield strengths greater than 150 ksi have included low-alloy martensitic steels, medium-alloy martensitic steels, nickel maraging steels, and bainitic steels. Only weldments from medium-alloy martensitic steels and nickel maraging steels have mechanical properties approaching those of the base plate without a complete postweld heat treatment. The most serious problem with the other steel is low toughness in the weld fusion zone. Adequate weld metal toughness under conditions of elastic strain can be obtarined over the entire 150 to 225 ksi yield-strength range only if the tungsten-arc welding process is used. Processes with higher deposition rates can produce comparable weld deposits only in the lower portion of the range. Above a yield strength of 200 ksi, 18Ni maraging steel weldments have the best combination of strength and toughness. Below 200 ksi, the HP 9-4-25 medium-alloy martensitic steel and 12Ni maraging steel weldments have nearly equal properties.

Fracture: An Advanced Treatise, Volume IV: Engineering Fracture Design presents the development and status of knowledge on sudden, catastrophic failure of structures due to unexpected brittle fracture of component materials. This book provides information pertinent to the engineering fracture design as well as the microscopic and macroscopic fundamentals of fracture. Organized into eight chapters, this volume begins with an overview of the evaluation of fracture tests. This text then presents an analysis of temperature effects on fracture. Other chapters consider the fracture and carrying capacity of long, slender columns and related topics. This book discusses as well the problems in connection with columns, beams, and plates, and experimental evidence to support theories proposed for describing the strength and stiffness of these elements. The final chapter presents an analysis of the problem of brittle fracture in weldments. This book is a valuable resource for engineers, students, and research workers in industrial organizations, education and research institutions, and various government agencies.

The Memorandum discusses the current situation on the inclusion of fracture-toughness testing requirements in specifications for high-strength steels used for military applications. The Memorandum was prepared at the request of The Technical Cooperation Program (TTCP), and contains information from Canadian and British members of that program, as well as U.S. information. Military applications discussed include missile motor cases, aircraft landing gear, gun tubes, armor plate, and hydrofoils. (Author).

This memorandum represents a combined effort by the U.S. Naval Applied Science Laboratory, Brooklyn, New York, and the Defense Metals Information Center to summarize new information on welding thick Ti plate. Thick plate of Ti continues to be of interest to the aerospace and defense industries for possible use in submersibles, armored vehicles, large space boosters, high-speed aircraft, and for pressure vessels. This memorandum generally is limited to information on welding Ti plate that is (1) at least 1 in. thick and (2) that is not covered by DMIC Report 185, The Status and Properties of Titanium Alloys for Thick Plate, June 14, 1963. The general requirements for welding Ti are not repeated here, since they are well documented in references mentioned in the inroduction to the memorandum. Sections have been prepared to cover material developments, welding-process developments, weld properties, and residual welding stresses. (Author).

Experimental programs concerned with the oxidation of titanium and its alloys are reviewed and results compared with those predicted by theory. Wagner-Hauffe theory is used as the primary basis for comparison, and its inconsistencies are pointed out. Fifteen binary alloy systems involving titanium are covered, as well as a few ternary and commercial alloys. A short section discusses the effects of oxygen or nitrogen contamination on the mechanical properties of titanium and its alloys. (Author).