Welding High-strength Steels


Book Description

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.




High-strength-steel Forgings


Book Description

THIS REPORT IS MAINLY CONCERNED WITH FORGINGS MADE FROM MARTENSITIC STEELS HEAT TREATED TO STRENGTHS RANGING FROM 240,000 TO 300,000 PSI. FORGING CHARACTERISTICS, DESIGN LIMITATIONS, DIMENSIONAL TOLERANCES, AND QUALITY-CONTROL PROBLEMS ARE DISCUSSED. A CONSIDERABLE AMOUNT OF DATA ON MECHANICAL PROPERTIES IS ALSO PRESENTED. IN ADDITION, THE REPORT SUMMARIZES THE AVAILABLE INFORMATION ON FORGED, SEMIAUSTENITIAL STEELS. THIS COMPILATION IS BASED ON PUBLISHED ARTICLES, GOVERNMENT REPORTS, AND INTERVIEWS WITH PRODUCERS AND USERS OF STEEL FORGINGS.







Cracking in High-strength Steel Weldments


Book Description

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 Numerous reports of investigations in this field are contained in the published and unpublished literature.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).




Properties of Coated Refractory Metals


Book Description

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.




Department of Defense Refractory Metals Sheet-rolling Program


Book Description

A summary is presented of the status of the Department of Defense Refractory Metals SheetRolling Program to accelerate the development of production techniques for high-quality, consistent sheet products from the refractory metals (Nb, Mo, Ta, and W) and their alloys. The program includes: (1) development of sheet production techniques, (2) establishment of minimum data re uired to evaluate mill production, (3) evaluation of fabrication characteristics of the sheet produced, and (4) establishment of design data. Contracts were awarded for the development of sheet production techniques for all four refractory metals. One contract was awarded for the evaluation of Mo alloy sheet fabrication characteristics. (Author).










Status Report No. 2 on Department of Defense Refractory Metals Sheet-rolling Program


Book Description

The Nb program is nearing completion of laboratory tory rolling studiory materials, *Heat resistant alloys, *Sheets, Niobium alloys, Molybdenum alloys, Tantalum alloys, Tungsten alloys, Titanium alloys, Zirconium alloys, Tungsten, Powder metallurgy, Electric arcs, Manufacturing methods, Mechanical proper ies, Forging, Heat treatment, Melting, Extrusion, Deformation, Hardness, Rolling mills, Processing. Identifiers: Floturning. The Nb program is nearing completion of laboratory tory rolling studies, and a single composition for larger scale rolling studies will be selected in the near future. In the Mo program, it has been shown that true hot forging of billets to sheet bar results in higher recrystallization temperatures of TZM and Mo-0.5Ti sheet than are obtained when normal forging temperatures are used. The Ta program is in the early stages of ingot production and primary breakdown fabrication of the Ta-30Nb-7.5V alloy. Three methods of fabricating W sheet are being investigated: rolling of powder-metallurgy billets, fabrication of arc-melted ingots, and floturning of cylindrical blanks. Properties obtained on both powdermetallurgy and arc-melted tungsten sheet compare very favorably. Evaluation of the formability of Mo-alloy sheet has been delayed until sheet is available from the production program. (Author).