The dependence of complex alloyed steel properties on quenching and tempering conditions

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M.P. Braun's school in the Scientific-Research Institute of Casting Problems, Ukrainian Academy of Sciences, the Ukraine, investigated the structure and properties of complex alloyed steels for many years, focusing on carbide formation and phase transformations. My son, Alexandr Vinokur, prior to his death, was working in the ScientificResearch E.O. Paton Institute of Electrical Welding, Ukrainian Academy of Science, the Ukraine, as a researcher. This article is a result of our collaboration and his input is invaluable. --BertoM B. Vinokur Morphology and structure of carbides in complex alloyed steels largely differ from those of carbides in the ordinary steels, mainly because complex alloyed steels contain more carbide forming elements. These elements vary the stability of carbides and their dissolution temperatures in austenite. The carbides in complex alloyed steels dissolve in austenite at higher temperatures and require longer dissolution times as compared to the ordinary steels, t~,2,31The level of carbide dissolution determines mechanical properties, sensibility to brittle fracture, hardenability, secondary hardness, etc. These characteristics develop during tempering and depend on the phase composition and the matrix alloying level. Complex alloyed steel with 0.28 pct carbon, 0.55 pct manganese, 0.26 pct silicon, 2.96 pct chromium, 1.37 pct nickel, 0.57 pct molybdenum, 0.36 pct tungsten, 0.019 pct sulfur, and 0.22 pct phosphorus was selected for the investigations. According to Soviet Standard GOST 4632-51, this steel can be indicated as 30X3HMB.* The Soviet stan*Compositions of alloyed steels are indicated based on the following rule: the numbers after the letters give the approximate percentage of the alloying elements. The number 1 or no number after the name of the alloying element means that the percentage of this alloying element is about one or less than one. The leading pair of numbers indicates the approximate carbon content in hundredths of 1 pct.

dard specification for this steel can be translated into English as 30Cr3NiMoW. This specification will be used in the article from now on. It is interesting to investigate steels with 3 pct Cr, be-

BERTOLD B. VINOKUR, Professor, is retired Doctor of Technical Science, Institute of Casting Problems, 34/1 Vemadsky Blvd., Kiev 252140, Ukraine, and currently resides at 3901 Conshohocken Ave., The Pavilion Apartment House, Apt. E-21, Philadelphia, PA 19131. VICTORIYA E. SHTESSEL, Research Specialist, is with the Materials Engineering Department, Drexel University, Philadelphia, PA 19104. ALEXANDR VINOKUR, formerly Engineer, Scientific-Research, E.O. Paton Institute of Electrical Welding, 11 Bozhenko St., Kiev 252005, Ukraine, is deceased. Manuscript submitted July 20, 1993. 2852--VOLUME 27A, SEPTEMBER 1996

cause they undergo carbide transformation on tempering even if there are no additional alloying elements present in the system,t41 Alloying with carbide forming elements changes the conditions of carbide transformation significantly,{51which in turn cha