A kind of medium silicon molybdenum niobium ductile iron material and preparation method thereof

Abstract

The invention discloses a medium silicon molybdenum niobium spheroidal graphite cast iron material and a preparation method thereof. The medium silicon molybdenum niobium spheroidal graphite cast iron material is prepared from the following chemical components in percentage by mass: 2.8-3.2% of C, 4.2-4.5% of Si, less than or equal to 0.4% of Mn, less than or equal to 0.04% of P, less than or equal to 0.015% of S, 0.8-0.9% of Mo, 0.6-0.9% of Ni, 0.4-0.7% of Nb, 0.03-0.06% of Mg, 0.15-0.25% of V and the balance of Fe and inevitable other elements. Since C04 high-purity pig iron and waste steel are taken as raw materials, a medium-frequency induction furnace is adopted for smelting, and a carburant, silicon carbide, ferrocolumbium, nickel plates, ferrosilicon and ferrovanadium are added in different time phases of smelting, raw iron chemical components and smelting temperature expected by design can be achieved, and the product disclosed by the invention can be prepared through nodulization and two times of inoculation. By adopting the edium silicon molybdenum niobium spheroidal graphite cast iron material disclosed by the invention, an exhaust manifold of an engine can work under a working condition of about 800 DEG C, the high-temperature use property of the exhaust manifold can be improved, and the service life of the exhaust manifold can be prolonged.

Description

technical field [0001] The invention relates to a nodular cast iron material and a preparation method thereof, in particular to a medium silicon molybdenum niobium nodular cast iron material and a preparation method thereof. Background technique [0002] Exhaust manifold is an important part of automobile internal combustion engine. It is a part that continuously operates at high temperature, must withstand the repeated action of high temperature gas, and is difficult to achieve forced cooling. With the advancement of science and technology, the automotive industry has increasingly strict requirements on energy saving and emission reduction. Over the years, the research work on improving the fuel combustion efficiency of internal combustion engines and reducing harmful gas emissions has never stopped. Due to the gradual increase in exhaust temperature, the material of the exhaust manifold has undergone frequent updates and replacements. The failure of the exhaust manifold m...

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Problems solved by technology

[0004] The existing problems in the existing technology are: the working temperature of the exhaust manifold made of medium silicon molybdenum ductile iron is ≤760°C, the working temperature of the high nickel austenitic ductile iron is ≤880°C, and the exhaust manifold of the two materials There is a big difference in cost, so between 760 and 880°C, there is a lack of a cast iron material that can be applied to the exhaust manifold and has an affordable cost

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