Effect of Forging Reduction Ratio on Anisotropy of Properties of Large Steel Forgings.

摘要

Published material on the quality of forgings as affected by the quality, purity, heat treatment and degree of forging of the steel is reviewed and analyzed. The literature examined related to steel 35KhM, 35KhNM, 40NM, 50KhN, 55Kh, 30KhGVM, 30Kh2GMT, 30Kh2G2MT, 40KhGVT, 35KhGNV, 35Kh2N2G, 35KhGN and 35KhGT. Forging reduction ratios of 4-6 appear optimum from the standpoint of obtaining good agreement of properties in the longitudinal and transverse directions in large articles of chromium-molybdenum chromium-nickel-molybdenum steels. The following conclusions were drawn on the effect of forging on the anisotropy of large forgings' properties. In the presence of pearlite steel structure, the plasticity and ductility always increase longitudinally and decrease transversely in the forging. Stable properties can be obtained in the transverse direction in sorbite structures, but they do increase logitudinally, although less than in the first case. With very limited hardenability, when only a thin surface layer is hardened, anisotropy increases with increasingly grain size. When hardenability is not complete, the anisotropy is extremely uneven through the cross section, increasing toward the center. (Author)