Process for casting heat-resistant steel or wear-resistant alloy steel by evaporative pattern casting (EPC)

Abstract

The invention discloses a process for casting heat-resistant steel or wear-resistant alloy steel by evaporative pattern casting (EPC). The process comprises the following steps of: purchasing raw materials, blending the materials, performing steelmaking, manufacturing a pattern, preparing a coating, brushing the coating, drying, pouring, testing, thermally processing, polishing, and packaging and warehousing. The invention further provides ingredients of the raw materials. The ingredients respectively are 0.3-0.8% of copper, 0.1-0.3% of molybdenum and 0.2-0.5% of chromium; molybdenum is added together with waste steel in a melting process; and copper is added together with molten iron into ladles in a tapping process. The invention also provides a preparation method of the coating. The coating comprises the following components in percentages by weight: 50-80% of fireproof material, 0.5-4% of adhesive, 1-3% of suspending agent, 0.5-3% of sodium dihydrogen phosphate and the balance of water, wherein the fireproof material is composed of bauxite, alundum powder, graphite powder or mullite powder. By adopting the method disclosed by the invention, effects of low cost, short processing period and good quality are achieved, the process of the method is reasonable, and the preparation effects of the raw materials and the coating are good, so the method is applicable to mass production and large-scale production.

Description

technical field [0001] The invention relates to a lost foam casting process, which belongs to the field of casting technology, in particular to a process of using lost foam casting heat-resistant steel or wear-resistant alloy steel. Background technique [0002] The traditional casting models are all wooden models, but because of their high production cost, waste of natural resources and long processing cycle, people have improved them. At present, models made of paraffin or foamed polyethylene (usually called benzene board) are directly buried in dry quartz sand for vibration molding to form a solid sand mold of benzene board. When molten iron is poured into this solid mold, polystyrene Combustion gasification, molten iron fills the space occupied by polystyrene, solidifies and cools to form a casting identical to the model. People usually call it lost foam casting, also known as dry sand full mold negative pressure casting, and it is called EPC abroad, which is one of the...

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Problems solved by technology

[0004] But its disadvantages are: firstly, the free carbon generated after polystyrene burning accumulates in the casting or on the surface of the casting to form carbon deposits, causing the processed surface to be scrapped due to carbon deposit defects; secondly, due to the benzene plate type coating layer In the process of pouring molten iron, it is easy to fall off and form a coating skin, resulting in casting defects such as skinning, slag inclusion, and sand sticking that are difficult to overcome; in addition, defects such as iron-clad sand, swelling, deformation, etc. Die casting is poor

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