CN101921904A - Spheroidal graphite cast iron crankshaft normalizing method without normalizing consumption - Google Patents
Spheroidal graphite cast iron crankshaft normalizing method without normalizing consumption Download PDFInfo
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Abstract
The invention provides a spheroidal graphite cast iron crankshaft normalizing method without normalizing consumption. In the method, smelting molten iron mainly comprises five elements in percentage by mass: 3.75-3.85 percent of C, 1.5-2.0 percent of Si, 0.82-0.87 percent of Mn, 0.04-0.08 percent of P and 0.001-0.024 percent of S; the molten iron flowing temperature is 1500-1520 DEG C, and the molten iron casting temperature is 1400-1450 DEG C; box opening after casting needs to meet the following requirements: in the continuous production, boxes are opened within 11-14 minutes after casting is finished; in the intermitted production, the boxes are opened within 10-13 minutes after casting is finished, and in the multi-box casting, the box opening temperatures of all crankshafts need to be controlled to be temperatures when hot boxes are opened within 11-14 minutes and cold boxes are opened within 10-13 minutes; and the castings after box opening are immediately conveyed into a cooling region, and the boxes of castings are arranged at intervals of 0.45-0.55m, and then, the castings are naturally cooled. The method stably obtains the spheroidal graphite cast iron superior to QT-800-2 national standard under the condition of unnecessarily reheating the castings and reduces the production cost for not rehabilitating the traditional sand-lined iron mold production line.
Description
Technical field
The present invention relates to spheroidal graphite cast iron thermal treatment field, specially refer to the method that the ductile iron crankshaft normalizing that normalizing expends does not take place.
Background technology
Publish China Machine Press in April, 1984 " the spheroidal graphite cast iron normalizing method recommended of thermal treatment handbook first fascicle is: foundry goods is heated to more than the Aci, makes matrix all change austenite into by insulation, implement air cooling then.Normalizing temperature to the spheroidal graphite cast iron that contains Si2.0～3.0%Mn 0.5～0.8% is 880～920 ℃, soaking time press H=casting thickness (mm)/5 (hour) calculate, can obtain higher either pearlite occurred and following mechanical property after the normalizing: σ b＞60 kgf/millimeters
2δ＞2% α k=1.5 kgfm/centimetre
2Hardness＞HB200.The weak point of this technology is: (1), foundry goods is heated to 880～920 ℃ and be incubated the corresponding time, expending of the corresponding energy and other must be taken place, only calculate by workshop cost, one ton of ductile iron crankshaft of normalizing expends about 608 yuan; (2), the mechanical property after the normalizing only satisfies the material requirements of QT600-2, can not directly apply on the material of QT800-2.
Country 2003 is called in " cast condition ductile iron technology " second batch of " state key industry clearer production technology guiding catalogue " lining name and mentions to the effect that: by control foundry goods speed of cooling, add alloying element, adjust chemical ingredients, adopt the compound inoculated measure of Denging, make foundry goods as cast condition reach the metallographic structure and the mechanical property of technical qualification regulation, thereby cancel heat treatment steps such as normalizing or annealing.The magnesium iron trade mark of as cast condition stably manufactured is: QT400-15, QT450-10, QT500-7, QT600-3, QT700-2.The weak point of this technology is that the ductile cast iron material trade mark that obtains is too low, all is lower than QT800-2, can not use in the high-grade nodular cast iron crank shaft field.
Jiangsu Province's Changzhou Diesel Engine Factory is mentioned waste heat (850 ℃) when utilizing foundry goods to unpack and hang defeated chain and send the blowing normalizing of spraying in " metal type sand-covering casting set technique ", obtaining the perlite more than 75%, thereby guarantee that foundry goods has the excellent comprehensive mechanical property.The shortcoming of this technology is: (1), the perlite more than 75% " its corresponding comprehensive mechanical performance can not satisfy high-grade nodular cast iron crank shaft and will reach technical requirements more than 80% to content of pearlite in alloy; (2), " hang defeated chain and send the blowing spraying " promoting difficulty at existing device for sand coated iron mould production line; (3), on existing device for sand coated iron mould line, utilization be subjected to the restriction that existing shop production line is arranged, it is big to transform infusion of financial resources; (4), " 850 ℃ " scope Zuo too, can not lucky 850 ℃ when unpacking, unactual in big production.
Shandong Province Binzhou Head Crankshaft Co., Ltd., the thinking of proposition " alloying is assisted in the bent axle waste heat normalizing " in " casting of bent axle device for sand coated iron mould and production process control " delivered on May 5th, 2009 in Yin scholar's literary composition on the automobile industry website, way is " the micro-Sb that adds the strong promotion perliteization of 0.5%～0.6% Cu and trace in the molten iron treating processes; when casting temperature is unpacked during the 860-900 ℃ of left and right sides; change foundry goods over to cooling room rapidly then and carry out spray cooling, so just can obtain the spherulitic iron crankshaft blank of content of pearlite in alloy 85%-90% mechanical property QT800-3.The defective of this technology is: (1), " need add 0.5%～0.6% Cu ",, when a copper valency high position was paced up and down, the electrolytic copper that adds in the iron liquid once reached 86000 yuan/ton, also was 63000 yuan/ton now, did not possess tangible economic benefit advantage; (2), " change cooling room rapidly over to and carry out spray cooling ", utilization is subjected to the restriction that existing shop production line is arranged on existing device for sand coated iron mould line.
Zhao Lijia, thanking to little equality delivers in " the bent axle process practice is produced in the waste heat normalizing " in " foundry engieering " 2003 the 24th the 04th phase of volume and proposes to produce with the composite alloying method, guarantee Cu content＞0.5%, when being cooled to 850 ℃, foundry goods unpacks, and the molding sand on bent axle surface is fallen in quick shake, evenly cooling is forced in the spraying of drying immediately, temper is carried out with electric furnace, reach the add-on that reduces automatic modeling crankshaft casting interalloy element, improve the comprehensive mechanical property of bent axle again, reduce production costs, produce the purpose of high-strength pearlitic bent axle, the defective of this technology is: (1), " produce assurance Cu content＞0.5% " with the composite alloying method, as previously mentioned, add cost partial offset that Cu increases its save the economic benefit that electric furnace heating normalizing produces; (2), " unpacking when being cooled to 850 ℃ " can not implemented in big production, 850 ℃ of temperature that are meant foundry goods, and foundry goods is in the swage the inside, it in swage outside the temperature that is difficult to learn the inside, even if after certain statistical study, the temperature of unpacking also can only be that being controlled at 850 ℃ is in the certain limit of intermediate value; (3), " molding sand on bent axle surface is fallen in shake fast " do not have this necessity, this process has reduced the temperature of delivering to the bent axle of forcing the cooling work step, be unfavorable for improving perlite ratio and comprehensive mechanical performance and in production reality, the bent axle molding surface shakes with sand (except that scab) overwhelming majority in the process of the demoulding of unpacking, local scab is very little to the quick refrigerative actual influence of foundry goods, has arrived negligible degree; (4), improve toughness with tempering again after the waste heat normalizing and also do not have this necessity, bent axle reaches trade mark performance index to improve toughness by tempering again is exactly function more than needed after the waste heat normalizing, toughness is below standard after the waste heat normalizing, improves to illustrate that then this technology does not reach the technical requirements of high trade mark spherulitic iron crankshaft with tempering.
Summary of the invention
The object of the present invention is to provide a kind of reasonable utilization and adjust the speed of cooling of foundry goods more than eutectoid line, be aided with the method that the ductile iron crankshaft normalizing that normalizing expends does not take place that the content of regulating perlite stable element Mn obtains to improve the foundry goods mechanical property, this method has been saved by electric furnace again to foundry goods heating normalizing step.
For achieving the above object, technical scheme of the present invention is:
The ductile iron crankshaft normalizing method that normalizing expends not taking place, be particularly useful for ductile cast iron casting, the ductile iron crankshaft normalizing method that normalizing expends does not take place the steps include:
1, in the spheroidal graphite cast iron smelting iron liquid, except that the Fe element, the mass percent of other C, Si, Mn, P, S five big principal elements is:
C、3.75-3.85％ Si、1.5-2.0％
Mn、0.82-0.87％ P、0.04-0.08％
S、0.001-0.024％；
2, electric furnace goes out the temperature of molten iron and is: 1500-1520 ℃;
3, the temperature of hot metal ladle pouring molten iron is: 1400-1450 ℃;
4, unpack and require in casting-up and cast back:
When device for sand coated iron mould production line is continuous production, when promptly being cast for hot-die, unpacked the foundry goods utilization deadweight demoulding in 11-14 minute from the cast end;
When device for sand coated iron mould production line is when be interrupted producing, when promptly being cast for cold mould, finish to unpack in 10-13 minute from cast, this moment, the cast(ing) surface temperature was controlled between 870-930 ℃, the foundry goods utilization demoulding of conducting oneself with dignity;
When device for sand coated iron mould production line was the cast of many casees, all swages time of unpacking all was controlled at from cast and finishes: hot-die is to unpack in 11-14 minute, cold mould be 10-13 minute unpacking;
5, foundry goods is controlled at 45-75 in second from the time of the demoulding of unpacking.
In the ductile iron crankshaft normalizing method that normalizing expends did not take place, the foundry goods that drops out of unpacking should be delivered to the cooling zone immediately, should put for 0.45-0.55 rice by the spacing distance between every case foundry goods to the foundry goods of delivering to the cooling zone, carries out naturally cooling.
Positively effect of the present invention is:
1, eliminates the cost that various normalizings take place, had remarkable economic efficiency;
2, foundry goods is not being heated under the condition of normalizing, stably obtaining to reach the ductile cast iron material of QT800-2 national standard;
3, alloying promotes not add expensive Cu in the production perlite technology, has further reduced production cost;
4, do not need existing device for sand coated iron mould line is carried out any transformation, do not need painstakingly to remove the residual sand of cast(ing) surface moulding, can implement the present invention, very easily promote in industry;
The temperature range that when 5, the present invention will unpack foundry goods will be allowed changes into the time of unpacking, and has strengthened the operability of technology, is convenient to promote the use in big production;
6, the present invention is simple to operate, and the spheroidal graphite cast iron mechanical property that obtains is higher than the QT800-2 national standard, and 3%, fragility was little when unit elongation was minimum, did not need tempering, has saved the technological process of electric furnace heating normalizing, and economic benefit is obvious.
Embodiment
Further specify the specific embodiment of the present invention below in conjunction with embodiment:
Embodiment 1
The sample title: the YTR4105 bent axle, casting weight: 54Kg, material requires: QT800-2, hardness requires: HB 240-320.
The site environment temperature is 20 ℃, pours into a mould at device for sand coated iron mould production line with same iron clad water.
1, the spheroidizing of spheroidal graphite cast iron smelting iron liquid in the electric furnace
Put into the spheroidizing material in hot metal ladle, the smelting iron liquid in the electric furnace is poured into carried out spheroidizing in the hot metal ladle, electric furnace molten iron tapping temperature is: 1501 ℃.
Except that the Fe element, the mass percent of other five big Elements C, Si, Mn, P, S is in the preceding spheroidal graphite Castiron Melting iron liquid of spheroidizing:
After the spheroidizing in the spheroidal graphite cast iron smelting iron liquid except that the Fe element, the mass percent of other five big Elements C, Si, Mn, P, S is:
2, unpack in casting-up and cast back
The hot metal ladle teeming temperature is: 1405 ℃, it is 12 minutes 2 seconds that foundry goods finishes to begin pitch time to unpacking from cast, and the cast(ing) surface temperature was 894 ℃ when foundry goods was unpacked.
3, foundry goods is 45 seconds from unpacking to demould time.
4, foundry goods time that the foundry goods drop out delivers to the cooling zone of unpacking is 55 seconds, and the foundry goods of delivering to the cooling zone is 0.45 meter by the spacing distance between every case foundry goods to be put, and carries out naturally cooling.
Foundry goods sampling metallographic and mechanical property detected result
Metallographic structure
Mechanical property:
Embodiment 2
The sample title: the YTR4105 bent axle, casting weight: 54Kg, material requires: QT800-2, hardness requires: HB 240-320.
1, the spheroidizing of spheroidal graphite cast iron smelting iron liquid in the electric furnace
Put into the spheroidizing material in hot metal ladle, the smelting iron liquid in the electric furnace is poured into carried out spheroidizing in the hot metal ladle, electric furnace molten iron tapping temperature is: 1510 ℃.
Except that the Fe element, the mass percent of other five big Elements C, Si, Mn, P, S is in the preceding spheroidal graphite Castiron Melting iron liquid of spheroidizing:
After the spheroidizing in the spheroidal graphite cast iron smelting iron liquid except that the Fe element, the mass percent of other five big Elements C, Si, Mn, P, S is:
2, unpack in casting-up and cast back
The temperature in molten iron when cast is: 1413 ℃, casting pouring finish to the time of the beginning of unpacking be 13 minutes 5 seconds, the cast(ing) surface temperature is 898 ℃ when unpacking.
3, foundry goods is 60 seconds from unpacking to demould time.
4, time that the foundry goods drop out delivers to the cooling zone of unpacking is 50 seconds, and the foundry goods of delivering to the cooling zone is 0.55 meter by the spacing distance between every case foundry goods to be put, and carries out naturally cooling.
Foundry goods sampling metallographic and mechanical property detected result
Metallographic structure
Mechanical property
The above only is a non-limiting embodiment of the present invention; for the person of ordinary skill of the art; not breaking away from the invention design and not making under the prerequisite of creative work, can also make some distortion and improvement, these all belong to protection scope of the present invention.
Claims (1)
1. one kind the ductile iron crankshaft normalizing method that normalizing expends does not take place, and is particularly useful for ductile cast iron casting, it is characterized in that, the ductile iron crankshaft normalizing method step that normalizing expends does not take place be:
(1), in the spheroidal graphite cast iron smelting iron liquid, except that the Fe element, the mass percent of other C, Si, Mn, P, S five big principal elements is:
C、3.75-3.85％ Si、1.5-2.0％
Mn、0.82-0.87％ P、0.04-0.08％
S、0.001-0.024％；
(2), electric furnace goes out the temperature of molten iron and is: 1500-1520 ℃;
(3), the temperature of molten iron pouring molten iron is: 1400-1450 ℃;
(4), unpack and require in casting-up and cast back:
When device for sand coated iron mould production line is continuous production, when promptly being cast for hot-die, unpacked the foundry goods utilization deadweight demoulding in 11-14 minute from the cast end;
When device for sand coated iron mould production line is when be interrupted producing, when promptly being cast for cold mould, finish to unpack in 10-13 minute from cast, this moment, the cast(ing) surface temperature was controlled between 870-930 ℃, the foundry goods utilization demoulding of conducting oneself with dignity;
When device for sand coated iron mould production line was the cast of many casees, all swages time of unpacking all was controlled at from cast and finishes: hot-die is to unpack in 11-14 minute, cold mould be 10-13 minute unpacking;
(5), foundry goods is controlled at 45-75 in second from the time of the demoulding of unpacking.
(6), the foundry goods drop out of unpacking should deliver to the cooling zone immediately, delivers to the foundry goods of cooling zone and should put for 0.45-0.55 rice by the spacing distance between every case foundry goods, carries out naturally cooling.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2010102576845A CN101921904B (en) | 2010-08-12 | 2010-08-12 | Spheroidal graphite cast iron crankshaft normalizing method without normalizing consumption |
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| CN2010102576845A CN101921904B (en) | 2010-08-12 | 2010-08-12 | Spheroidal graphite cast iron crankshaft normalizing method without normalizing consumption |
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| CN101921904A true CN101921904A (en) | 2010-12-22 |
| CN101921904B CN101921904B (en) | 2011-11-09 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107326140A (en) * | 2017-06-30 | 2017-11-07 | 宁夏共享集团股份有限公司 | A kind of high strength and high hardness ductile cast iron material and its method of smelting |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5980715A (en) * | 1982-10-30 | 1984-05-10 | Mazda Motor Corp | Production of spheroidal graphite cast iron having high resistance to fatigue |
| JP2002038217A (en) * | 2000-07-26 | 2002-02-06 | Ube Steel Co Ltd | Method for producing cast iron component |
| CN1472356A (en) * | 2003-04-26 | 2004-02-04 | 广西玉林玉柴机器配件制造有限公司 | Manufacturing method for nodular cast iron |
| CN1900328A (en) * | 2005-07-19 | 2007-01-24 | 辽宁五一八内燃机配件有限公司 | Heat treatment process for large microalloyed medium carbon steel engine crankshaft |
-
2010
- 2010-08-12 CN CN2010102576845A patent/CN101921904B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5980715A (en) * | 1982-10-30 | 1984-05-10 | Mazda Motor Corp | Production of spheroidal graphite cast iron having high resistance to fatigue |
| JP2002038217A (en) * | 2000-07-26 | 2002-02-06 | Ube Steel Co Ltd | Method for producing cast iron component |
| CN1472356A (en) * | 2003-04-26 | 2004-02-04 | 广西玉林玉柴机器配件制造有限公司 | Manufacturing method for nodular cast iron |
| CN1900328A (en) * | 2005-07-19 | 2007-01-24 | 辽宁五一八内燃机配件有限公司 | Heat treatment process for large microalloyed medium carbon steel engine crankshaft |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107326140A (en) * | 2017-06-30 | 2017-11-07 | 宁夏共享集团股份有限公司 | A kind of high strength and high hardness ductile cast iron material and its method of smelting |
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Granted publication date: 20111109 Termination date: 20130812 |