CN103357822A

CN103357822A - Nodular cast iron timing gear casting process

Info

Publication number: CN103357822A
Application number: CN2012101001619A
Authority: CN
Inventors: 田应旭
Original assignee: ZUNYI KAIHANG MACHINERY MANUFACTURING Co Ltd
Current assignee: ZUNYI KAIHANG MACHINERY MANUFACTURING Co Ltd
Priority date: 2012-04-06
Filing date: 2012-04-06
Publication date: 2013-10-23

Abstract

The invention relates to a nodular cast iron timing gear casting process. On the basis of a conventional modeling method, two dead heads and one pouring gate are arranged; the pouring gate can also be used as the dead head, the size of the pouring gate is compact and closed moulding sand; an ingate is semi-annular; during pouring, nodular cast iron liquor flows into the ingate through the pouring gate and then flows into a gear cavity through the ingate; because the ingate is semi-annular, so that the iron liquid can enter the gear cavity stably, and can effectively avoid the oxidation of iron liquid; in the process of pouring, two dead heads play a role of feeding; when the pouring is finished, two dead heads and one pouring gate play a role of feeding at the same time. According to the invention, a process form of combining a pouring system and a dead head for feeding and graphitization swell are combined to eliminate the casting defect, thus obtaining the gear casting with high inside and outside quality, and the percent of pass of casting is improved greatly.

Description

A kind of spheroidal graphite cast-iron timing gears casting technique

Technical field

The invention belongs to the machine casting field, particularly a kind of casting technique of timing gear ofr automobile engine.

Background technology

Automobile engine generally adopts forging or steel casting with the timing gears foundry goods, but because blank allowance is large, the waste machining period, less economical, the major subjects that therefore development has intensity and cast steel is more or less the same, wearability is good, spheroidal graphite cast-iron that noise is low becomes various countries' research.Ductile iron gear has similar to cast steel characteristic, good casting property, the characteristics that noise is low.Timing gears are one of in-engine core components, require to have certain intensity, toughness, casting flaw is little, reduces as far as possible allowance.But spheroidal graphite cast-iron easily produces the defectives such as shrinkage cavity, slag inclusion when casting causes gear to be scrapped.Only stipulated that for spheroidal graphite cast-iron mechanical property there is no the chemical composition requirement in the national standard.Therefore, adopt the cost of different raw material processing timing gears foundry goods to be very different, in the face of the national cast iron market competitive pressure, each foundry enterprise all reduces manufacturing cost as much as possible under how research is satisfying condition, improve the market competitiveness.

Summary of the invention

The object of the present invention is to provide the suitable component of a kind of energy control, change traditional running gate system, reduce rising head quantity, utilize self graphitization expansion feeding to improve the casting yield of foundry goods, obtain to satisfy the casting technique of the spheroidal graphite cast-iron timing gears foundry goods of mechanical property.

A kind of spheroidal graphite cast-iron timing gears casting technique on conventional formative method basis, is provided with 2 rising heads and 1 cast gate, and cast gate can double as rising head and use, and is of a size of φ 40 * 150mm, and molding sand compacts fine and closely woven; Ingate adopts semi-circular;

During cast, ductile iron liquid flows into ingate by cast gate, flows into gear cavity through ingate again, is semi-circular because ingate adopts, so iron liquid is more steady when entering gear cavity, can effectively avoid iron liquid oxidation; In the casting process, 2 rising heads play the feeding effect, and when being poured, 2 rising heads and 1 cast gate play the feeding effect simultaneously.

The present invention adopts the process form of running gate system and rising head associating feeding and has eliminated casting defect in conjunction with graphitization expansion.Obtained all high gear foundry goods of inherent and external quality, casting qualified rate reaches 98%～100%.And the timing gears blank size precision that adopts the present invention to process is high, and interior tissue is tight, and allowance is few, and is stable and reliable for performance.

Description of drawings

Fig. 1 is the mould assembly casting figure of timing gears casting technique of the present invention.

Among the figure: 1-rising head, 2-cast gate, 3-rising head, 4-running channel, 5-molding sand, 6-gear cavity.

The specific embodiment

In actual production, the raw material of timing gear ofr automobile engine nearly all are the spheroidal graphite cast-iron that adopts, if adopt traditional processing method, manufacturing cost is higher, and easily produce shrinkage cavity, the defective such as slag inclusion causes gear to be scrapped, be not suitable for producing in enormous quantities.The technical staff to the raw-material component of suitable control, changes traditional running gate system, reduces rising head quantity by research, utilizes self graphitization expansion feeding to improve the casting yield of foundry goods, and the spheroidal graphite cast-iron timing gears foundry goods of mechanical property is satisfied in acquisition.Technical scheme of the present invention is:

1, the shared mass percent of each component is in the spheroidal graphite cast-iron timing gears: C:3.3～3.45%, Si:2.25～2.35%, Mn:0.35～0.45%, P:0.05～0.06%, S:0.03～0.04%, Mg:0.02～0.03%, RE:0.01～0.02%, Ba:0.005～0.01%, Sb:0.003～0.008%, surplus are Fe.

2, the casting technique of spheroidal graphite cast-iron timing gears of the present invention:

(1), the mould structure of timing gears adopts the blossom type design, one the case 6, to improve the utilization rate of material;

(2), method of manufacturing technology of the present invention was made of stages such as melting, castings.Below in conjunction with accompanying drawing 1, spheroidal graphite cast-iron timing gears casting technique of the present invention is described in further detail.And take alloy material employing QT500-7 as the embodiment of the invention, spheroidal graphite cast-iron timing gears method of manufacturing technology of the present invention is described in detail.

For improving the material actual recovery rate, on conventional formative method basis, be provided with rising head 1, rising head 3 and cast gate 2, cast gate 2 can double as rising head uses, and is of a size of φ 40 * 150mm, and molding sand 5 compacts fine and closely woven.For being conducive to deslagging, adopting semi-circular ingate 4 radially to introduce.During cast, ductile iron liquid flows into ingates 4 by cast gate 2, flows into gear cavities 6 through ingate 4 again, is semi-circular because ingate 4 adopts, so iron liquid is more steady when entering gear cavity 6, can effectively avoid the oxidation of iron liquid.In the casting process, rising head 1, rising head 3 play the feeding effect, and when being poured, rising head 1, rising head 3 and cast gate 2 play feeding simultaneously.

Pouring technology of the present invention is laid side riser in cast gate 2 one sides.Eliminated casting defect with the process form of this running gate system and rising head associating feeding and in conjunction with graphitization expansion.Obtained all high gear foundry goods of inherent and external quality, casting qualified rate 98%～100%, the foundry goods yield rate is more than 85%.A kind of to have dimensional accuracy high by obtaining after the above process, dense internal organization, and allowance is few, foundry goods stable and reliable for performance.

The invention has the beneficial effects as follows: the forging type that waters by cancelling flanging string in the past, avoid using driving to wait stripping tool for high to make small-sized foundry goods, minimizing rising head quantity has improved the utilization rate of material.Comparing cast steel, forging timing gears product, to have allowance few, and cutting is easy to characteristics.

Claims

1. spheroidal graphite cast-iron timing gears casting technique, it is characterized in that: on conventional formative method basis, be provided with rising head (1), rising head (3) and cast gate (2), cast gate (2) can double as and be the rising head use, be of a size of φ 40 * 150mm, molding sand (5) compacts fine and closely woven; Described ingate (4) adopts semi-circular;

During cast, ductile iron liquid flows into ingate (4) by cast gate (2), pass through again ingate (4) and flow into gear cavity (6), because what ingate (4) adopted is semi-circular, more steady when therefore iron liquid enters gear cavity (6), can avoid the oxidation of iron liquid; In the casting process, rising head (1), rising head (3) play the feeding effect, and when being poured, rising head (1), rising head (3) and cast gate (2) play the feeding effect simultaneously.