CN104818423A - Exhaust manifold production process capable of improving casting fluidity - Google Patents
Exhaust manifold production process capable of improving casting fluidity Download PDFInfo
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- CN104818423A CN104818423A CN201510192989.5A CN201510192989A CN104818423A CN 104818423 A CN104818423 A CN 104818423A CN 201510192989 A CN201510192989 A CN 201510192989A CN 104818423 A CN104818423 A CN 104818423A
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Abstract
The invention discloses an exhaust manifold production process capable of improving casting fluidity. The process is used for casting an exhaust manifold of ductile cast iron, and comprises the following sequential steps: melting the raw material, adjusting the component, casting and annealing, wherein the heat preservation of a blank is performed in stages in the annealing treatment step; the casting step also comprises a molten metal static head heightening step. The process has a simple route, primary carbide in the product is conveniently eliminated, meanwhile the fluidity of the molten metal in the casting process is good, the casting fluidity is favorably improved, and the product quality and the production efficiency are facilitated.
Description
Technical field
The present invention relates to automobile component method field of manufacturing, particularly relate to a kind of exhaust manifold production technique improving cast mobility.
Background technology
Exhaust manifold, be connected with engine cylinder block, the exhaust of each cylinder put together and imports exhaust-gas receiver, with the gas barrier of tap line, exhaust manifold all has considerable influence to the cost of engine power performance, Fuel Economy energy, emission standard, engine, the car load front deck layout of coupling and temperature field etc.
Exhaust manifold is one of part that in trolley part, working conditions is the most severe simultaneously, subjects the temperature variation from envrionment temperature to nearly thousand degrees Celsius, also will meet the requirements such as resistance to air loss, weather resistance and patency simultaneously in working process.In prior art, motor car engine is just towards the future development of miniaturization, power increaseization, and this just makes the exhaust pressure of cylinder also increase, and this proposes requirements at the higher level to performances etc. such as the intensity of exhaust manifold.The good heat resistance of spheroidal graphite cast iron, still has the higher vehicle of a large amount of exhaust temperature to continue to use the exhaust manifold that material is spheroidal graphite cast iron in prior art, it is so the important topic in automotive industry that Study and Development goes out that more superior exhaust manifold casting technique appoints.
Summary of the invention
For the good heat resistance of above-mentioned spheroidal graphite cast iron, the higher vehicle of a large amount of exhaust temperature is still had to continue to use the exhaust manifold that material is spheroidal graphite cast iron in prior art, Study and Development goes out more superior exhaust manifold casting technique and appoints the right problem for the important topic in automotive industry, the invention provides a kind of exhaust manifold production technique improving cast mobility.
For the problems referred to above, a kind of exhaust manifold production technique improving cast mobility provided by the invention reaches goal of the invention by following technical essential: a kind of exhaust manifold production technique improving cast mobility, for the exhaust manifold casting that material is spheroidal graphite cast iron, comprise the following steps that order is carried out: starting material thawing, constituent adjustment, cast and anneal; In described annealing process step, the insulation of blank is carried out stage by stage, the soaking time of first stage is between 2-3h, holding temperature is between 890-930 DEG C, after insulation, stove is chilled to subordinate phase, and the soaking time of subordinate phase is between 1.5-2h, and holding temperature is 710-735 DEG C, after insulation, stove is chilled to the phase III, the soaking time of phase III is between 3-4h, and holding temperature, between 580-610 DEG C, is incubated rear air cooling; In described cast step, also comprise molten metal bath statical head and increase work step, described statical head increases work step for apply stress on casting mold, and the applying method of stress is for be placed in sprue cup on casting mold.
In the present invention, by the restriction to annealing process step, the process characteristic carried out stage by stage by anneal, can realize the Full Annealing to casting finished products, eliminates the primary carbide in finished product; Owing to abandoning manifold each several part variable thickness, in the region that foundry goods wall is thinner, because molten metal bath has spheroidization and inoculation process in starting material thawing or constituent adjustment step, for avoiding producing cold shut and underpriming, statical head being set and increasing work step, the velocity of flow of molten metal in die cavity can be accelerated like this, statical head is increased to the further restriction of work step simultaneously, adopt ready-made sprue cup, cast can be completed efficiently, therefore this operational path also helps efficiency of the present invention.
Further technical scheme is:
After described constituent adjustment step ends, in molten metal, the content of carbon is between 3.4-3.7%, and the content of element silicon is between 1.7-2.6%, and the content of magnesium elements is between 0.02-0.03%; The initial temperature of described cast step is between 1370-1430 DEG C; Be easy to obtain as a kind of and be convenient to the proportioning raw materials form of constituent adjustment, in starting material thawing step, starting material used comprise pig iron Q10, ferrosilicon, rare earth magnesium iron alloy.After ending to constituent adjustment step, in molten metal, the restriction of the initial temperature restriction of composition, cast step makes in the blank metallographic structure obtained, and graphite form is good, and matrix comprises the perlite that content is less than 4.5%; Coordinate the processing parameter of annealing process step to limit, make the tensile strength of the blank obtained be not less than 530MPa, hardness HB is between 165-170.
As one nucleating agent of good performance, described ferrosilicon is FeSi75Al3.
As a kind of ferrosilicon form being beneficial to blank performance, described ferrosilicon is abrasive grit, and the granularity of abrasive grit is between 5-12mm.
For avoiding the Segregation of Chemical Composition of molten metal bath in casting process or being too oxidized, the time that described cast step continues is not more than 8s.
For the benefit of casting mold upper surface quality, when sprue cup is placed on casting mold, casting mold upper end is provided with venting hole.
The present invention has following beneficial effect:
Present invention process route is simple, and by the restriction to annealing process step, the process characteristic carried out stage by stage by anneal, can realize the Full Annealing to casting finished products, eliminates the primary carbide in finished product; Owing to abandoning manifold each several part variable thickness, in the region that foundry goods wall is thinner, because molten metal bath has spheroidization and inoculation process in starting material thawing or constituent adjustment step, for avoiding producing cold shut and underpriming, statical head being set and increasing work step, the velocity of flow of molten metal in die cavity can be accelerated like this, statical head is increased to the further restriction of work step simultaneously, adopt ready-made sprue cup, cast can be completed efficiently, therefore this operational path also helps efficiency of the present invention.
Embodiment
Below in conjunction with embodiment, the present invention is described in further detail, but structure of the present invention is not limited only to following examples.
Embodiment 1:
A kind of exhaust manifold production technique improving cast mobility, for the exhaust manifold casting that material is spheroidal graphite cast iron, comprise the following steps that order is carried out: starting material melt, constituent adjustment, cast and anneal, in described annealing process step, the insulation of blank is carried out stage by stage, the soaking time of first stage is between 2-3h, holding temperature is between 890-930 DEG C, after insulation, stove is chilled to subordinate phase, the soaking time of subordinate phase is between 1.5-2h, holding temperature is 710-735 DEG C, after insulation, stove is chilled to the phase III, the soaking time of phase III is between 3-4h, holding temperature is between 580-610 DEG C, air cooling after insulation, in described cast step, also comprise molten metal bath statical head and increase work step, described statical head increases work step for apply stress on casting mold, and the applying method of stress is for be placed in sprue cup on casting mold.
In the present invention, by the restriction to annealing process step, the process characteristic carried out stage by stage by anneal, can realize the Full Annealing to casting finished products, eliminates the primary carbide in finished product; Owing to abandoning manifold each several part variable thickness, in the region that foundry goods wall is thinner, because molten metal bath has spheroidization and inoculation process in starting material thawing or constituent adjustment step, for avoiding producing cold shut and underpriming, statical head being set and increasing work step, the velocity of flow of molten metal in die cavity can be accelerated like this, statical head is increased to the further restriction of work step simultaneously, adopt ready-made sprue cup, cast can be completed efficiently, therefore this operational path also helps efficiency of the present invention.
Embodiment 2:
The present embodiment is further qualified on the basis of embodiment 1: after described constituent adjustment step ends, in molten metal, the content of carbon is between 3.4-3.7%, the content of element silicon is between 1.7-2.6%, and the content of magnesium elements is between 0.02-0.03%; The initial temperature of described cast step is between 1370-1430 DEG C.After ending to constituent adjustment step, in molten metal, the restriction of the initial temperature restriction of composition, cast step makes in the blank metallographic structure obtained, and graphite form is good, and matrix comprises the perlite that content is less than 4.5%; Coordinate the processing parameter of annealing process step to limit, make the tensile strength of the blank obtained be not less than 530MPa, hardness HB is between 165-170.
Be easy to obtain as a kind of and be convenient to the proportioning raw materials form of constituent adjustment, in starting material thawing step, starting material used comprise pig iron Q10, ferrosilicon, rare earth magnesium iron alloy.
As one nucleating agent of good performance, described ferrosilicon is FeSi75Al3.
As a kind of ferrosilicon form being beneficial to blank performance, described ferrosilicon is abrasive grit, and the granularity of abrasive grit is between 5-12mm.
For avoiding the Segregation of Chemical Composition of molten metal bath in casting process or being too oxidized, the time that described cast step continues is not more than 8s.
For the benefit of casting mold upper surface quality, when sprue cup is placed on casting mold, casting mold upper end is provided with venting hole.
Above content is the further description done the present invention in conjunction with concrete preferred implementation, can not assert that the specific embodiment of the present invention is confined to these explanations.For general technical staff of the technical field of the invention, not departing from other embodiments drawn under technical scheme of the present invention, all should be included in protection scope of the present invention.
Claims (6)
1. one kind can be improved the exhaust manifold production technique of cast mobility, for the exhaust manifold casting that material is spheroidal graphite cast iron, comprise the following steps that order is carried out: starting material melt, constituent adjustment, cast and anneal, it is characterized in that, in described annealing process step, the insulation of blank is carried out stage by stage, the soaking time of first stage is between 2-3h, holding temperature is between 890-930 DEG C, after insulation, stove is chilled to subordinate phase, the soaking time of subordinate phase is between 1.5-2h, holding temperature is 710-735 DEG C, after insulation, stove is chilled to the phase III, the soaking time of phase III is between 3-4h, holding temperature is between 580-610 DEG C, air cooling after insulation, in described cast step, also comprise molten metal bath statical head and increase work step, described statical head increases work step for apply stress on casting mold, and the applying method of stress is for be placed in sprue cup on casting mold.
2. a kind of exhaust manifold production technique improving cast mobility according to claim 1, it is characterized in that, after described constituent adjustment step ends, in molten metal, the content of carbon is between 3.4-3.7%, the content of element silicon is between 1.7-2.6%, and the content of magnesium elements is between 0.02-0.03%;
In starting material thawing step, starting material used comprise pig iron Q10, ferrosilicon, rare earth magnesium iron alloy.
3. a kind of exhaust manifold production technique improving cast mobility according to claim 2, it is characterized in that, ferrosilicon is FeSi75Al3.
4. a kind of exhaust manifold production technique improving cast mobility according to claim 3, it is characterized in that, described ferrosilicon is abrasive grit, and the granularity of abrasive grit is between 5-12mm.
5. a kind of exhaust manifold production technique improving cast mobility according to claim 1, it is characterized in that, the time that described cast step continues is not more than 8s.
6. a kind of exhaust manifold production technique improving cast mobility according to claim 1, it is characterized in that, when sprue cup is placed on casting mold, casting mold upper end is provided with venting hole.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510192989.5A CN104818423A (en) | 2015-04-22 | 2015-04-22 | Exhaust manifold production process capable of improving casting fluidity |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201510192989.5A CN104818423A (en) | 2015-04-22 | 2015-04-22 | Exhaust manifold production process capable of improving casting fluidity |
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| CN104818423A true CN104818423A (en) | 2015-08-05 |
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| CN201510192989.5A Pending CN104818423A (en) | 2015-04-22 | 2015-04-22 | Exhaust manifold production process capable of improving casting fluidity |
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Application publication date: 20150805 |