Metal Science and Heat Treatment

Zhmud, E.

doi: 10.1007/BF00700558pmid: N/A

There is considerable interest in methods of improving the service life of steel tools by cold treatment, first proposed in the USSR in 1937. In contrast to the usual treatment of steel with cold, which must be conducted from room temperature directly after quenching, shock cooling can be used both in the process of heat treatment and after finishing of the tool. Cold treatment can be conducted with the tools both at room temperature and high temperature (especially the solutioning temperature).

Smol'nikov, E.; Kossovich, G.

doi: 10.1007/BF00700559pmid: N/A

At factories where the specified heat treatment is closely adhered to and quality control is practiced, the treatment in liquid nitrogen does not improve tool life.

Tseitlin, L.; Kolesnichenko, V.; Karnaushenko, T.; Umanets, V.; Zhmud', E.

doi: 10.1007/BF00700560pmid: N/A

Popandopulo, A.; Zhukova, L.

doi: 10.1007/BF00700561pmid: N/A

1. Shock cooling of quenched steel induces transformation not only of austenite but also martensite. For this reason, the cold treatment should be used for parts and tools with no retained austenite in order to intensify the processes of tempering and precipitation hardening. Tool life increases 20–30% in this case. 2. Cold treatment of tools with 15–20% retained austenite restores the cutting ability to almost the same level as for tools without retained austenite. 3. To prevent cracking and embrittlement of tools and to increase tool life by 50–100%, it is recommended that the cold treatment be conducted after tempering at 560° for 1 h with final tempering at 400° for 30–60 min.

Zablotskii, V.; Klets, Yu.; Sharaban, N.; Gubarev, V.

doi: 10.1007/BF00700562pmid: N/A

1. After cold treatment in liquid nitrogen the mechanical properties of the steels are somewhat lower than after standard heat treatment. The cutting properties are not impaired in this case. In the course of the cold treatment the retained austenite is more completely transformed, particularly in high-carbon high-speed steels. However, use of this treatment to reduce the number of temperings is possible only in cases where the lower mechanical properties do not impair the cutting properties. 2. The main reason for the lower mechanical properties of high-speed steel subjected to the cold treatment is the smaller quantity of secondary martensite when retained austenite is transformed in the process of standard tempering.

Kukhtin, M.; Cheremnykh, V.

doi: 10.1007/BF00700563pmid: N/A

1. The small additions (up to 0.15%) of REM to commercial steels with harmful impurities interact only with oxygen and sulfur (and also selenium if it is present). 2. At elevated concentrations (tenths of a percent) the REM may form compounds not only with oxygen and sulfur but also with phosphorus, arsenic, antimony, lead, bismuth, tin, copper, nickel, and iron. The possibility of a particular compound being formed and the quantity depend on the concentrations of REM, harmful impurities, and the basic elements of the metal. 3. The activity of REM with respect to elements entering into the composition of the steel or alloy agrees with the position of the element in the periodic table and diminishes in the following order: groups VIB, VB, IVB, IIIB, IB, VIII.

Krylov, V.; Anisimova, M.; Panov, V.

doi: 10.1007/BF00700564pmid: N/A

1. The resistance to elongation and the rate of strengthening of steel 12Kh18N10T at different temperatures vary in a complex manner with the deformation, which determines the development of the γ→α and γ→ε transformations. The largest even elongation is observed at 0°, when with >4% deformation the martensitic transformation is initiated, accompanied by a relatively low rate of strengthening in a broad range of deformations. 2. The greatest reduction of δe as the result of hydrogenation is observed at 0°, and the minimal value of ψ at −40°. 3. Hydrogenation in an amount of 25 cm3/100 g of metal has no effect on the strength or structural stability of steel 12Kh18N10T. 4. The hydrogen cracks in steel 12Kh18N10T are located within single grains around carbonitrides along the line of formation of martensite or parallel to twins.

Rozhkova, S.; Osintseva, A.

doi: 10.1007/BF00700565pmid: N/A

1. The Cr-Mn steels tested have a good combination of mechanical properties at +20 and −190°, are strengthened by cold plastic deformation, and retain high ductility.

Maleev, D.; Novokshonova, A.; Samoilovich, S.; Feofilov, R.

doi: 10.1007/BF00700566pmid: N/A

Konyukhov, G.; Bedarev, A.; Beloborodov, G.; Il'yushko, E.; Murav'ev, V.; Sharko, A.

doi: 10.1007/BF00700567pmid: N/A

1. For quenching of alloys D16, V95, and AK4-1, a 0.3–1.0% PEO solution with molecular weight≥3·106 is optimal. The permissible thickness of the quenched part varies with the type of alloy and PEO concentration. 2. The distortion after quenching in 0.5% PEO solution is 4–5 times smaller than after quenching in water, while the mechanical properties and corrosion resistance of semifinished products of alloys D16, V95, and AK4-1 meet the technical specifications. 3. The extent of decomposition of the solid solution in alloy D16 quenched in PEO solutions can be determined by the acoustical method.