Metal Science and Heat Treatment

Speidel, M.

doi: 10.1007/s11041-006-0017-ypmid: N/A

The effect of nitrogen on the strength, ductility, and corrosion resistance of nitrogen-bearing austenitic stainless steels is studied. Fields of application of these steels are considered.

Katada, Y.; Washizu, N.; Baba, H.

doi: 10.1007/s11041-006-0018-xpmid: N/A

High-nitrogen steels (HNS) with more than 1 wt.% nitrogen and without manganese have been developed at the National Institute for Materials Science of Japan with the use of a pressure electroslag remelting device. Such steels have low content of impurities, high resistance to localized corrosion, and good mechanical properties. A possible mechanism for raising the resistance to localized corrosion by increasing the nitrogen content is considered.

Aleksandrov, S.; Hulka, K.; Stepashin, A.; Morozov, Yu.

doi: 10.1007/s11041-006-0019-9pmid: N/A

The strength and ductility characteristics, toughness parameters, and structure of low-alloy steels after thermomechanical treatment are studied. Analysis of the properties of steels with various manganese-to-niobium ratios is performed. An optimum chemical composition for sheet steel subjected to thermomechanical treatment is suggested.

Kodjaspirov, G.; Sulyagin, R.; Karjalainen, L.

doi: 10.1007/s11041-006-0020-3pmid: N/A

The effect of the temperature and deformation conditions of high-temperature thermomechanical treatment (HTMT) on the processes of hardening and softening of corrosion-resistant steels with up to 0.5% nitrogen is studied. Axisymmetric single and double compression and stress relaxation tests are performed with the help of Gleeble 1500 installation that ensures physical simulation of thermomechanical treatment. The hardening is determined in terms of changes in the hardness.

Suikkanen, P.; Kömi, J.; Karjalainen, L.

doi: 10.1007/s11041-006-0021-2pmid: N/A

The effect of hot deformation and chemical composition on the microstructure and hardness of experimental grades of low-carbon and ultralow-carbon C-Mn-Mo-Nb-B steels is studied by the method of physical simulation. It is shown that deformation of austenite at a temperature below that of recrystallization leads to formation of polygonal ferrite and high-temperature ferrite with bainitic morphology. The effect is the most pronounced in boron-bearing steels. Simultaneous alloying with Mo, Nb, and B seems to be the most effective for ensuring high hardness.

Sadikova, G.; Latysh, V.; Semenova, I.; Valiev, R.

doi: 10.1007/s11041-006-0022-1pmid: N/A

The effect of different modes of combined treatment on the microstructure and mechanical properties of long-length semiproducts from commercial purity titanium is studied. The combined production process includes equal-channel angular pressing followed by thermomechanical treatment. Special features of formation of an ultrafine-grain structure in preforms and changes in mechanical properties are studied in different stages of the process. A comparative analysis of mechanical characteristics of titanium in the initial annealed state and after the combined treatment is performed. Scattering of mechanical properties over the length of preforms is studied.

Michalski, J.; Tacikowski, J.; Wach, P.; Lunarska, E.; Baum, H.

doi: 10.1007/s11041-006-0023-0pmid: N/A

Results on the formation of a layer of γ′-nitride on the surface of carbon steel in the process of controlled gas nitriding (NITREG®) are presented. In the formation of single-phase layers of γ′-nitride it is necessary to control thoroughly the nitriding atmosphere including the stage when the treated material is heated to the process temperature. A mathematical formula relating the nitriding atmosphere with the value of the nitriding potential is suggested. Results of corrosion tests and metallographic studies of γ′-nitride layers are described.

Pokorska, I.

doi: 10.1007/s11041-006-0024-zpmid: N/A

Structure and properties of composite layers obtained by combining the processes of electrolytic chromizing and nitriding or oxynitriding activated by glow discharge plasma are studied. It is shown that such diffusion layers possess high corrosion resistance and enhanced wear resistance.

Gupta, R.; Nayan, N.; Ghosh, B.

doi: 10.1007/s11041-006-0025-ypmid: N/A

An analytical evaluation of homogenization of aluminum alloy AA2219 with different grain sizes is performed. The homogenization parameters are computed with the use of diffusion laws and under the assumption that a low-melting eutectic can form in alloys of the Al-Cu system. With allowance for the difference in the grain sizes a two-stage homogenization regime is shown to be optimum for alloy AA2219.

Gupta, R.; Ghosh, B.; Sinha, P.

doi: 10.1007/s11041-006-0026-xpmid: N/A

Several modes of heat treatment are tested with the aim of raising the hardness of Cu-9% Al-6%Ni-5%Fe aluminum bronze used for fabricating axial piston pumps of launching systems. A high hardness ensuring resistance to abrasion wear is one of the main requirements on the material.