Reference

Surface hardening of low-carbon steel

Surface hardening of low-carbon steel. Hashimoto, Hiroshi (Seikosha Co., Ltd., Japan). Japan. Kokai JP 52076235 27 Jun 1977 Showa, 5 pp. (Japanese). (Japan). CODEN: JKXXAF. CLASS: IC: C23C009-04. APPLICATION: JP 75-153734 23 Dec 1975. DOCUMENT TYPE: Patent CA Section: 55 (Ferrous Metals and Alloys) Low-C steels are chromized and then boronized. Thus, a steel specimen S10C [12725-33-6] was embedded in a mixt. contg. powd. Cr (-200 mesh) 60, Al2O3 (-400 mesh) 37, and NH4Cl 3%, heated in Ar atm. at 1050.degree. for 2 h to coat with a 70-.mu.-thick Fe-Cr solid soln. layer of Vickers hardness 180. Then, the steel was boronized by embedding in a mixt. contg. ferroboron [11108-67-1] 77, Al2O3 17, and K2SiF6 [16871-90-2] 6% and heating in N atm. at 1050.degree. for 2 h. The Vickers hardness was 2560.

Copper mold for continuous casting of steel

Copper mold for continuous casting of steel. Hara, Senri; Kimura, Tomohiko; Tomono, Hiroshi; Inoue, Kunio (Sumitomo Metal Industries, Ltd., Japan). Japan. Kokai JP 52054622 4 May 1977 Showa, 3 pp. (Japanese). (Japan). CODEN: JKXXAF. CLASS: IC: B22D011-04. APPLICATION: JP 75-131740 31 Oct 1975. DOCUMENT TYPE: Patent CA Section: 55 (Ferrous Metals and Alloys) Steel-contacting surfaces of Cu or Cu alloy molds for continuous casting of steel are electroplated with Ni and then with Cr to prevent the adhesion of molten steel to the molds during initial period of casting. Thus, a continuous-casting Cu mold was coated with a vinyl paint, excepting the steel-contacting surfaces, degreased, electroplated with a 250-.mu.-thick Ni layer by immersing in a soln. (pH 4.5) contg. Ni sulfamate 450, NiCl2 40, H3BO3 20, and Na naphthalenetrisulfonate [26856-59-7] 3 g/L at 50.degree. and applying elec. current at 1 A/dm2 for 20 h, and then electroplated with a 5-.mu.-thick Cr layer by immersing in a soln. contg. Cr2O3 320, H2SO4 0.8, and K2SiF6 [16871-90-2] 5 g/L and applying elec. current at 25 A/dm2 for 20 min. When the mold was used for continuous casting of steel, no adhesion of steel was obsd.