Preparation method of material suitable for diesel engine cylinder cover

Abstract

The invention relates to a preparation method of a material suitable for a diesel engine cylinder cover. The preparation method of the material suitable for the diesel engine cylinder cover comprisesthe following steps of (1) adopting steel scraps and foundry return as furnace charges, sequentially adding into an intermediate frequency furnace, melting to obtain molten iron, and adding a petroleum coke carburant when the temperature of the molten iron reaches to 1400 DEG C; (2) when the temperature of the molten iron reaches to 1530 to 1560 DEG C, adding ferro manganese nitride, uniformly stirring, and tapping after preserving heat for 8 to 12 minutes; (3) adding an inoculator into a ladle for the first time, starting inoculation treatment for the second time when the molten iron in the ladle accounts for one third of the tapping amount, and adding a metal-stream inoculation agent for the third time in the molten iron pouring process; and (4) adopting a sand-lined metal mold casting mold for pouring to obtain a gray cast iron material suitable for the diesel engine cylinder cover. According to the preparation method of the material suitable for the diesel engine cylinder cover provided by the invention, through adding a nitrogen element, reducing the alloy element content, improving the inoculation times and combining a sand-lined metal mold process for casting, so that the mechanical property and the strength of the gray iron material are remarkably improved, and the cracking problem caused by low material strength and heat fatigue of the diesel engine cylinder cover at present are solved.

Description

technical field [0001] The invention belongs to the technical field of diesel engines, in particular to a method for preparing materials suitable for diesel engine cylinder heads. Background technique [0002] With the continuous development of high-horsepower and high-speed engines, higher requirements are placed on cylinder head materials, which not only require high strength and toughness, but also require good wear resistance and fatigue performance. Most of the high-strength cylinder head gray cast iron materials on the market are increased by adding alloys, which increases the cost, reduces the competitiveness of the market, and affects the overall development of the engine factory. In order to solve this problem, it is necessary to develop a gray cast iron material with less alloy addition but improved strength to adapt to the development of the market. [0003] At present, the common production method of gray cast iron cylinder head is: pig iron, scrap steel, return...

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Problems solved by technology

[0003] At present, the common production method of gray cast iron cylinder head is: pig iron, scrap steel, returned iron and other alloys are used as the furnace material to be melted into molten iron in the intermediate frequency furnace. : 0.06-0.11%, Mn: 0.55-0.95%, Cu: 0.55-0.85%, Cr: 0.16-0.42%, P<0.07%) After passing the inspection, add an inoculant to the iron for treatment, and the particle size of the inoculant is required to be 3- 8mm, adding secondary inoculation during pouring, final molten iron composition requirements: C: 3.15-3.45%, Si: 1.93-2.12%, S: 0.06-0.11%, Mn: 0.55-0.95%, Cu: 0.55-0.85% , Mo: 0.15-0.35%, Cr: 0.16-0.42%, Sn: 0.05-0.15%, P<0.07%) the alloy content of the obtained gray cast iron material is relatively high, but the performance is low, and the tensile strength of the cylinder head body is 230-250Mpa , the hardness is 180-190HBW, the cost is high, and it is difficult to improve the market competitiveness of the product

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