Abstract: A method for manufacturing iron-based metallurgical parts, the method comprising: mixing graphite powder; pressing; presintering; oxidizing the presintered metallurgical part to form an oxide layer having a thickness of 1 ?m to 50 ?m on its surface to form an oxidized presintered metallurgical part; sintering; machining; carburizing; quenching and tempering. An oxide layer is formed on the surface of a part by oxidization, oxygen in the oxide layer is chemically reacted with the carbon in the surface layer of the product during the sintering, and the resulting product enters a sintering atmosphere in the form of gas to form a decarburized layer having a certain thickness on the surface of the part, so that the decarburization is realized.

Abstract: A method for preparing nano-SiO2 reinforced aluminum matrix composites, includes the following: Step-1, powder mixing: mixing aluminum matrix powder with nano-SiO2 powder to obtain raw material powder, wherein the aluminum matrix powder has an average particle size between 30 ?m to 100 ?m, the nano-SiO2 powder has an average particle size between 5 nm to 145 nm, mass percentage of nano-SiO2 in the raw material powder is 0.01% to 5% and the remaining raw material powder is the aluminum matrix powder; Step-2, shaping: press shaping the powder obtained in the Step-1 to obtain base bodies; Step-3, sintering: sintering the base bodies obtained in the Step-2 in an atmosphere of N2 at 550° C. to 660° C., preserving the temperature for a period of 5 min to 60 min, and cooling in a furnace at end of the period under protection of N2 for 0.5 h to 3 h; and Step-4, heat treatment.