Process for low pressure casting and forming fuel common-rail jet pump of diesel engine
Technical field
The present invention relates to a kind of extrusion process, particularly a kind of process for low pressure casting and forming fuel common-rail jet pump of diesel engine.
Background technology
Low-pressure casting process is the normal a kind of method that adopts of a kind of hot investment casting, is applied to the comparatively complicated aluminium casting production of structure, is a kind of Countergravity casting method; In the casting process, the injection direction of aluminium liquid is opposite with gravity direction.Because the low pressure casting liquid metals is the filling die cavity under pressure, to form a kind of method of foundry goods, used pressure is lower.Its technical process is in the crucible (or hermetically sealed can) of sealing, feeds dry compressed air, and molten metal is under the effect of gas pressure, rise along stalk, enter die cavity reposefully by cast gate, and keep the gas pressure on the liquid level in the crucible, till foundry goods solidifies fully.Remove the gas pressure on the liquid level then, make out not solidified metal liquid stream crucible in the liquid pipe, again by the cylinder open form and release foundry goods.
To fill type more steady for liquid metals in the low pressure casting process; Casting forming is good, helps forming the foundry goods of clear-cut, any surface finish; Foundry goods dense structure, the mechanical performance height; Do not need rising head generally speaking, so the technology recovery rate of molten metal is higher in the casting process; Simultaneously, equipment is simple, easily realizes mechanization and automation, also is the outstanding advantage of low pressure casting.
The low pressure casting product of aluminium and alloy thereof can satisfy the needs of most of plant equipment, but in the precision optical machinery manufacture process, such as diesel electric-controlled high pressure fuel common-rail jet, require high for the inherent pinhole rate of the pump housing, and common low-pressure casting process is difficult to reach comparatively satisfied qualification rate, not only reduce operating efficiency, reduce the output of product, also be easy to break down.
Therefore, the low-pressure casting process that needs a kind of aluminium and the alloy pump housing thereof, in the casting solidification process of the aluminium and the alloy pump housing thereof, there is not shrinkage porosite, particularly comparatively significantly the partial interior feeding is abundant in structural change, pore-free produces, can effectively control the pinhole rate of product inside, satisfy the requirement of the inside and outside quality of product, improve the qualification rate of product.
Summary of the invention
In view of this, purpose of the present invention provides a kind of process for low pressure casting and forming fuel common-rail jet pump of diesel engine, in the casting solidification process of the aluminium and the alloy pump housing thereof, there is not shrinkage porosite, particularly comparatively significantly the partial interior feeding is abundant in structural change, pore-free produces, can effectively control the pinhole rate of product inside, satisfy the requirement of the inside and outside quality of product, improve the qualification rate of product.
Process for low pressure casting and forming fuel common-rail jet pump of diesel engine of the present invention comprises matched moulds, mould and die preheating, rises liquid and fill type and solidify and die sinking pickup step,
In the mould and die preheating step, the preheat temperature of upper die and lower die, side form and core is 200 ℃;
Rise liquid fill type solidify comprise in order rise liquid, fill type, supercharging, pressurize and blowdown step:
Wherein rising the liquid time is 5 seconds, pressure 10KPa; Filling time 5 seconds, pressure 15KPa; Pressurization time is 20 seconds, pressure 35KPa; Dwell time is 110 seconds, pressure 260KPa; The pressure release time is 3 seconds.
Beneficial effect of the present invention: process for low pressure casting and forming fuel common-rail jet pump of diesel engine of the present invention, to reasonably cooperating on mold preheating temperature, mold filling pressure and the filling time, in the casting solidification process of the aluminium and the alloy pump housing thereof, there is not shrinkage porosite, particularly comparatively significantly the partial interior feeding is abundant in structural change, pore-free produces, can effectively control the pinhole rate of product inside, satisfy the requirement of the inside and outside quality of product, improve the qualification rate of product.
The specific embodiment
The process for low pressure casting and forming fuel common-rail jet pump of diesel engine of present embodiment comprises matched moulds, mould and die preheating, rises liquid and fill type and solidify and die sinking pickup step,
In the mould and die preheating step, the preheat temperature of upper die and lower die, side form and core is 200 ℃;
Rise liquid fill type solidify comprise in order rise liquid, fill type, supercharging, pressurize and blowdown step:
Wherein rising the liquid time is 5 seconds, pressure 10KPa; Filling time 5 seconds, pressure 15KPa; Pressurization time is 20 seconds, pressure 35KPa; Dwell time is 110 seconds, pressure 260KPa; The pressure release time is 3 seconds.
Explanation is at last, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although the present invention is had been described in detail with reference to preferred embodiment, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technical scheme of the present invention, and not breaking away from the aim and the scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.