Provided is a black heart malleable cast iron and a method for manufacturing the same which can significantly shorten the time required for graphitization, as compared with the prior art. The black heart malleable cast iron includes a matrix of ferrite and lump graphite included in the matrix, and includes at least one selected from the group consisting of (i) 0.0050% by mass or more and 0.15% by mass or less of bismuth and 0.020% by mass or more of manganese, and (ii) 0.0050% by mass or more and 1.0% by mass or less of aluminum and 0.0050% by mass or more of nitrogen. In addition, the grain size of the matrix is 8.0 or more and 10.0 or less in terms of grain size number, numerically determined by comparison between a metallographic photograph of the matrix and a standard grain size chart.

Provided is a black heart malleable cast iron and a method for manufacturing the same which can significantly shorten the time required for graphitization, as compared with the prior art. The black heart malleable cast iron includes a matrix of ferrite and lump graphite included in the matrix, and includes at least one selected from the group consisting of (i) 0.0050% by mass or more and 0.15% by mass or less of bismuth and 0.020% by mass or more of manganese, and (ii) 0.0050% by mass or more and 1.0% by mass or less of aluminum and 0.0050% by mass or more of nitrogen. In addition, the grain size of the matrix is 8.0 or more and 10.0 or less in terms of grain size number, numerically determined by comparison between a metallographic photograph of the matrix and a standard grain size chart.

The invention relates to a steel alloy comprising, in percent by mass:—0.17 to 0.23 carbon;—1.40 to 1.60 silicon;—0.50 to 0.60 manganese;—up to 0.020 phosphor;—up to 0.020 sulfur;—up to 0.30 chrome;—up to 0.12 molybdenum;—up to 0.80 nickel;—up to 0.30 copper;—up to 0.03 vanadium; the remainder being iron and incidental impurities.

A composite roll for rolling having a structure comprising centrifugally cast outer and intermediate layers of an Fe-based alloy integrally fused to an inner layer of ductile cast iron; the outer layer having a composition comprising by mass 1-3% of C, 0.3-3% of Si, 0.1-3% of Mn, 0.5-5% of Ni, 1-7% of Cr, 2.2-8% of Mo, 4-7% of V, 0.005-0.15% of N, and 0.05-0.2% of B, the balance being Fe and inevitable impurities; the intermediate layer containing 0.025-0.15% by mass of B; the B content in the intermediate layer being 40-80% of that in the outer layer; and the total amount of Cr, Mo, V, Nb and W in the intermediate layer being 40-90% of that in the outer layer.

A method and system for manufacturing a cast iron crankshaft for a vehicle are provided. The system comprises a molding unit arranged to form a negative sand cast mold of the cast iron crankshaft. The mold comprising at least one molded cavity having a pattern with dimensions of the cast iron crankshaft. The system further comprises a feeding mechanism comprising a riser having a connector through which molten metallic material flows to the cast mold. The feeding mechanism feeds the molten metallic material at a riser connection angle in the at least one mold cavity. The riser connection angle corresponds to a connector modulus. The connector modulus is 20% greater than a cast modulus. The riser geometry corresponds to a riser modulus. The riser modulus is 20% greater than the connector modulus. The system further comprises a furnace, a cooling area, a separation unit, a controller and a power source.

A method and system for manufacturing a cast iron crankshaft for a vehicle are provided. The system comprises a molding unit arranged to form a negative sand cast mold of the cast iron crankshaft. The mold comprising at least one molded cavity having a pattern with dimensions of the cast iron crankshaft. The system further comprises a feeding mechanism comprising a riser having a connector through which molten metallic material flows to the cast mold. The feeding mechanism feeds the molten metallic material at a riser connection angle in the at least one mold cavity. The riser connection angle corresponds to a connector modulus. The connector modulus is 20% greater than a cast modulus. The riser geometry corresponds to a riser modulus. The riser modulus is 20% greater than the connector modulus. The system further comprises a furnace, a cooling area, a separation unit, a controller and a power source.

An iron alloy material for casting includes 0.3 to 3.5 mass% of C, 0.1 to 3.0 mass% of Si, 26.0 to 42.0 mass% of Ni, 0.02 to 0.50 mass% of Sb, and a balance that is Fe and an inevitable impurity/impurities.

An iron alloy material for casting includes 0.3 to 3.5 mass% of C, 0.1 to 3.0 mass% of Si, 26.0 to 42.0 mass% of Ni, 0.02 to 0.50 mass% of Sb, and a balance that is Fe and an inevitable impurity/impurities.

A hypereutectic chromium white iron alloy which comprises, in weight percent based on the total weight of the alloy, from 1.5 to 2.85 carbon, from 0.01 to 1.2 nitrogen, from 0.1 to 1.4 boron, from 3 to 34 chromium, from 0.1 to 7.5 Ni, and from 0.1 to 4 Si. The alloy may optionally comprise one or more additional elements, i.e., manganese, cobalt, copper, molybdenum, tungsten, vanadium, niobium, titanium, zirconium, magnesium and/or calcium, one or more rare earth elements, and one or more of tantalum, hafnium, aluminum. The remainder of the alloy is constituted by iron and unavoidable (incidential) impurities. Articles cast from the alloy, especially cryogenically hardened articles, are also disclosed.

A hypereutectic chromium white iron alloy which comprises, in weight percent based on the total weight of the alloy, from 1.5 to 2.85 carbon, from 0.01 to 1.2 nitrogen, from 0.1 to 1.4 boron, from 3 to 34 chromium, from 0.1 to 7.5 Ni, and from 0.1 to 4 Si. The alloy may optionally comprise one or more additional elements, i.e., manganese, cobalt, copper, molybdenum, tungsten, vanadium, niobium, titanium, zirconium, magnesium and/or calcium, one or more rare earth elements, and one or more of tantalum, hafnium, aluminum. The remainder of the alloy is constituted by iron and unavoidable (incidential) impurities. Articles cast from the alloy, especially cryogenically hardened articles, are also disclosed.