CN104550725A

CN104550725A - Method for investment casting automobile heat-resistant steel exhaust manifold

Info

Publication number: CN104550725A
Application number: CN201310516285.XA
Authority: CN
Inventors: 刘升迁
Original assignee: QINGDAO TIANHENG MACHINERY CO Ltd
Current assignee: QINGDAO TIANHENG MACHINERY CO Ltd
Priority date: 2013-10-29
Filing date: 2013-10-29
Publication date: 2015-04-29

Abstract

The invention discloses a method for investment casting an automobile heat-resistant steel exhaust manifold. The method disclosed by the invention comprises the following steps: manufacturing a core by taking urea as a mould core material and water as a dissolution medium through a free casting and forming method, then, removing oil and grease from a module, and completely drying and hardening a coating and a sanding layer so as to obtain a mould shell; and then, roasting the mould shell, smelting alloy, casting, shaking out sand and cleaning to obtain a fusible mould casting. By means of the method disclosed by the invention, the problems of being more in process and high in workload in the prior art are overcome; the production efficiency is improved; the quality defect due to the common problems of the automobile engine heat-resistant steel exhaust manifold casting, such as local shrinkage porosity and shrinkage cavity, is avoided; the utilization rate of raw materials is high; the production cost is reduced; the cast finished product is precise in size and unnecessary to machine; and thus, the quality of the casting is effectively ensured.

Description

Heat-resistant steel exhaust manifold for automobile investment casting method

Technical field

The invention belongs to casting technology field, be specifically related to a kind of heat-resistant steel exhaust manifold for automobile investment casting method.

Background technology

The model casting of automobile engine heat-resistant steel exhaust manifold roughly comprises manufacture wax-pattern, manufactures the steps such as shell, alloy smelting, cast, knockout, cleaning.In current melt film casting technique, the heat-resistant steel exhaust manifold for automobile investment-casting finished product made there will be local shrinkage porosite phenomenon, and not only casting process is more, affects production capacity, and the precision of foundry goods cannot effectively be ensured simultaneously, and percent defective is higher.

Summary of the invention

In order to overcome the above-mentioned technical problem that prior art field exists, the object of the invention is to, a kind of heat-resistant steel exhaust manifold for automobile investment casting method is provided, can directly cast out heat-resistant steel exhaust manifold for automobile investment-casting, bolt precision is accurate, and processing technology thereof is simple.

Heat-resistant steel exhaust manifold for automobile investment casting method provided by the invention, comprises the following steps:

(1) take urea as core material, water is dissolve medium; Fusion temperature 100-150 DEG C, adopt free casting forming method to make core under mold temperature 50-80 DEG C of conditions, core adopts K501 wax, change wax temperature 80-100 DEG C; Penetrate wax temperature 50-70 DEG C; Penetrate wax pressure 20Kg/cm2-60Kg/cm2; Dwell time is 20S-80S; Coolant water temperature is make wax-pattern under 5-25 DEG C of conditions; Use laminar flatiron, the connecting portion of wax-pattern is melted, make that wax-pattern is welded together is assembled into module;

(2) oil removing of module and degreasing: be coated with coating and stucco on module, before being coated with coating, first stirs coating; After coating coats, carry out stucco; Wherein layer of sand is three layers, is surface layer respectively: 320 order zirconium powders joined by Ludox, dry 5-10 hours; Transition zone: 320 order mullite powders joined by Ludox, dry 5-10 hours; Back-up coat: 320 order mullite powders joined by Ludox, dry 10-15 hours; Obtain shell blank; Molten mistake fusible pattern: after coating and stucco layer bone dry also harden, melt dewax module with hot-water process, obtain shell; Roasting shell: the shell after dewaxing is put into heating furnace, heats to 1000-1200 DEG C, be incubated 0.5-2 hours; High-performance shell is obtained by said procedure;

(3) adopt intermediate frequency furnace melting, before cast, spectrum on line analyzes alloying component, guarantees to obtain the qualified cast product of composition;

(4) pouring temperature 1580 DEG C, formwork preheat temperature 1000 DEG C; The duration of pouring 10S;

(5) mode adopting mechanical oscillation sand removal and chemical soda boiling sand removal to combine also is cleared up.

Heat-resistant steel exhaust manifold for automobile investment casting method provided by the invention, its beneficial effect is, overcomes operation in prior art process more, the problem that workload is large, improves production efficiency; Avoid the mass defect because the problems such as automobile engine heat-resistant steel exhaust manifold foundry goods local Shinkage and dispersed porosity cause, utilization rate of raw materials is high, reduces production cost; The finished product melt film casting dimension cast out is accurate, without the need to machining, effectively ensure that casting quality.

Detailed description of the invention

Below in conjunction with an embodiment, heat-resistant steel exhaust manifold for automobile investment casting method provided by the invention is described in detail.

Embodiment

The heat-resistant steel exhaust manifold for automobile investment casting method of the present embodiment, comprises the following steps:

(1) take urea as core material, water is dissolve medium; Fusion temperature 130 DEG C; Adopt free casting forming method to make core under mold temperature 65 DEG C of conditions, core adopts K501 wax, change wax temperature 90 DEG C; Penetrate wax temperature 60 C; Penetrate wax pressure 40Kg/cm2; Dwell time: 45S; Coolant water temperature: make wax-pattern under 15 DEG C of conditions; Use laminar flatiron, the connecting portion of wax-pattern is melted, make that wax-pattern is welded together is assembled into module;

(2) oil removing of module and degreasing: be coated with coating and stucco on module, before being coated with coating, first stirs coating; After coating coats, carry out stucco; Wherein layer of sand is three layers, is surface layer respectively: 320 order zirconium powders joined by Ludox, dry 8 hours; Transition zone: 320 order mullite powders joined by Ludox, dry 10 hours; Back-up coat: 320 order mullite powders joined by Ludox, dry 13 hours; Obtain shell blank; Molten mistake fusible pattern: after coating and stucco layer bone dry also harden, melt dewax module with hot-water process, obtain shell; Roasting shell: the shell after dewaxing is put into heating furnace, heats to 1010 DEG C, be incubated 1 hour; High-performance shell is obtained by said procedure;

Heat-resistant steel exhaust manifold for automobile investment casting method, can directly cast out satisfactory investment-casting, and without the need to machining, operation is simple, and the heat-resistant steel exhaust manifold for automobile investment-casting size of the finished product cast out is accurate, effectively ensure that casting quality.

Claims

1. a heat-resistant steel exhaust manifold for automobile investment casting method, is characterized in that, said method comprising the steps of:

(1) take urea as core material, water is dissolve medium; Fusion temperature 100-150 DEG C; Adopt free casting forming method to make core under mold temperature 50-80 DEG C of conditions, core adopts K501 wax, change wax temperature 80-100 DEG C; Penetrate wax temperature 50-70 DEG C; Penetrate wax pressure 20Kg/cm2-60Kg/cm2; Dwell time: 20S-80S; Coolant water temperature: make wax-pattern under 5-25 DEG C of conditions; Use laminar flatiron, the connecting portion of wax-pattern is melted, make that wax-pattern is welded together is assembled into module;