Showing papers on "Gray iron published in 1989"

Influence of laser heating on the quantity residual austenite in steels and cast irons

Abstract: 1. The quantity of residual austenite in the case fused under the action of a heat source (laser or plasma) on the surface of steel or iron is unambiguously determined by the parameter P/d (dv)0.4, which is proportional to the maximum temperature at the end of action of the source. 2. In 9Kh steel with an increase in the parameter P/d (dv)0.4 the quantity of residual austenite in laser fusion changes according to a curve with a maximum. In treatment with scanning of the laser beam the quantity of residual austenite in 9Kh steel continusouly increases with an increase in the parameter P/d (dv)0.4. The addition of scanning leads to an increase in the quantity of residual austenite in the case in comparison with treatment without scanning. 3. With an increase in the parameter P/d (dv)0.4 the change in the quantity of residual austenite in the zone of surface fusion of gray irons is dependent upon the degree of solution of graphite in the molten material. 4. The contact fatigue life of 9Kh steel after laser fusion of the surface is a maximum with 50–60% residual austenite in the laser hardened case. The wear resistance of gray iron after surface fusion increases with an increase in the quantity of residual asustenite in the case hardened from the liquid state.

Porous body of iron system

Abstract: PURPOSE:To enable the improvement of heat resistance and the increase of voids of the title porous body obtd. by binding flattened spiral metallic pieces, crushed spiral metallic pieces and/or planar metallic pieces by a ceramics binder and specifying the contents of said metallic pieces and binder. CONSTITUTION:Respectively prescribed ratios of the spiral metallic pieces and the silica ceramics binder are mixed and the mixture is packed into a die having a square section on the inside surface. After this mixture is pressurized, the molding is parted from the die. The molding is solidified by drying and is heated to prepare the porous body consisting of 10-95wt.% flattened spiral metallic pieces, 2-60% above-mentioned binder, and the balance the crushed spiral metallic pieces and/or the planar metallic pieces. The spiral metallic pieces are preferably spheroidal graphite cast iron or steel and the planar metallic pieces are preferably spheroidal graphite cast iron or gray iron. This porous body is thereby provided with the excellent heat resistance and large voids and in addition, the porous body is changeable of voids. The porous body is, therefore, adequate for sound absorbing material, sound insulating material, vibration dampers, magnetic shields, and electromagnetic shields.