The molding tool usually the expiration of various different circumstance happens during the period of producing application, a great deal of wasted manpower, material resources, influenced production progress.The reason and prevention measure of a few basic expiration forms and expiration that mainly relate a molding tool as follows.
First, Molding tool is expired
Cold hot molding tool in the middle of undergoing military service the expired basic form can is divided into:The Su transforms;Wear away;Tired;Split.
(1)The Su transforms.
The Su transforms namely bear carry is bigger than to accept defeat transforming of strength but creation.Fall to sink such as the cave mold appeared chamber, type bore the extension and sharp angle tumble down to sink and the convex mold appears Dun thick, lengthways bent etc..Particularly hot make a molding tool, it works surface and heat material contact, the made chamber surface temperature usually exceeds heat to make the returning of molding tool steel fire temperature, type the wall inside the slot is collapsed under pressure or press a heap because of softening.When the low Cui deeply sexual steel kind was used to a cold Dun mold, molding tool after the Cui fire heats, to inside the bore carried on spraying water cooling to produce a hardening layer.Molding tool while using, such as the cold Dun dint lead greatly, hardening layer underneath of the base anti- press to accept defeat strength not high, the molding tool bore chamber is collapsed under pressure.The molding tool steel accepts defeat strength generally with the content of carbon(c) from the increasing of some metal alloy chemical elementses but go up, in the degree of hardness under the same circumstance, the steel of different chemistry composition has of the anti- press strength different, following 4 kinds of anti-s of steels accept defeat strength while being the steel degree of hardness as 63 HRCs one by one in order in proper order from Gao Dao Di is:The W18 Cr4 V>Cr 12> Cr6 WV>5 CrNiWs.
(2)Wear away expiration.
Wearing away expiration means that bluntness in the blade door turns, the sharp angle changes circle, flat surface the bottom sinks, surface ditch scar, peeling off glue a film.(in the middle of rubbing molding tool work form but glued some Pis to anticipate metal)Moreover, the convex mold is in the work, because of lubricant burnable after convert into high pressure air, carry on to the convex mold surface violent flush, the formation annoys eclipse.
Cold blunt, if carry not and greatly, wear away a type mainly in order to oxidize, wearing away can also match to wear away for biting of a certain degree and be a blade the part change bluntness or blunt press burden a little bit greatly, biting to match a worn circumstance will become serious, but make to wear away speed, the bearing of molding tool steel whets sex to not only be decided by its degree of hardness, but also be decided to the property, size of carburet and distribute with amount, in the molding tool steel, the bearing of high-speed steel and high chrome steel whets sex currently higher.But under the sistuation that exist to there is the carburet that the carburet of severity is partial to Xi or big grain in the steel, these carburets are easily peeling off, but cause to whet a grain to wear away and make to wear away to speed.A little bit lightly cold make a molding tool of the impact of steel(the lamella is blunt to cut, pull to stretch, flection etc.), don't greatly carry a lotus, mainly for quiet wear away.At quiet wear away a condition under, the containing of molding tool steel amount of carbon is many and bear to whet sex big.Under the sistuation that the impact wears away(like cold Dun, cold crowded and hot Duan etc.), the excessive carburet of no help to exaltation bears to whet sex in the molding tool steel, on the contrary because the impact whets a grain to wear away, but lowers to bear to whet sex.
The research expresses that under the sistuation that the impact whets a grain to wear away, the molding tool steel contains amount of carbon with O.6% for upper limit, cold Dun mold under the sistuation that the impact carries a lotus work, if the carburet in the molding tool steel is excessive, the easily solid impact wears away but mountain the surface is peeling off now.These peeling off hard grain sons will become whetting a grain and quickly wear away speed.Hot make the type of molding tool of chamber surface, makes to bear to whet sex to lower because the heat softens, oxidize sheet iron to also have the function to whet to anticipate in addition, there is still heat oxidizing to decay a function in the meantime.
(3)Tired expiration.
Tired characteristic of the expiration:The molding tool some parts has been definitely undergone military service a period and rose small crack, and gradual deeply expand to the Zong, seriously weaken the loading ability of molding tool but cause to split while expanding to the certain size.The tired crack is risen to in response to the dint bigger part, especially in response to dint concentration part(size transition, indentation, knife scar, wear away crack etc.), the fatigue broke a door to divide two parts while splitting, one part forms for the tired crack development of the tired place broken cross section, present shell-like in shape, the tired source is located on shell top.In order to suddenly split, another part presents the whole rough cross section of gravamen.
Make the molding tool taken place the root reason of tired harm for especially the wreath carries a lotus, any can make the surface pulled the factor that enlarges in response to the dint to can accelerate rising of tired crack all.
Cold make a molding tool when the work is under the high hard appearance the molding tool steel has very high accept defeat strength and split a tenacity very lowly.Gao of accept defeat strength to be advantageous to the creation that postpones tired crack, but lowly split a tenacity to make expanding of tired crack the velocity speed to let up with critical length and make the circulating number consumedly shortenned, therefore, cold the tired life span making a molding tool be mainly decided by tired crack to rise time.
Hot make a molding tool generally at in etc. or lower degree of hardness appearance the bottom undergoes military service, the molding tool splits a tenacity compare cold make a molding tool of Gao De Duo, therefore, makes a molding tool in the heat in, the expanding of tired crack speed is lower than cold make a molding tool, the critical length is bigger than cold make a mold, the heat makes the molding tool tired crack of second critical expand a period colder make a mold to grow much, but hot make the molding tool surface is subjected to nasty cold, the nasty heat rises cold hot tired crack very easily, the heat makes the tired crack of molding tool to rise time compare cold make a mold short get many, therefore, many heats make a mold it is mainly tired to split life span to is decided by time that the tired crack expands.
(4)Split expiration.
Split an expired familiar form to have:Collapse blade, Gua Chi, split crack, break, the bulge split etc., the different molding tool splits of the driving force is different.Cold make a molding tool, be subjected to of mainly is a machine function dint.(blunt pressure)The heat makes a mold be subjected to in addition to machine dint, there is also heat in response to the dint and the organization and there are higher many works temperatures that the heats make a molding tools in response to the dint, again the adoption compulsorily cool off, its internal help dint can far far above machine in response to the dint, therefore, many heats make a splitting of mold mainly with internal help dint lead greatly relevant.
The molding tool splits process to have 2 kinds:1 time splits and tired split.1 time splits for the molding tool sometimes at blunt suddenly split while pressing, crack once rising, after then losing is steady and expands.Its main reason overloads for severity or the molding tool material serious frailty turns.(if leading is hot and returns to fire shortage, seriously gather ten in response to the dint and serious metallurgy blemish etc.)
Second, Molding tools lose efficacy reason and prevention measure
(1)The structure design absurdity causes expiration.
Sharp turn Cape(here in response to dint concentrated is higher than mean stress decuple above) and lead greatly cut noodles variety to result in concentrated in response to the dint, usually become many molding tools in early days expired source.And in the hot processing Cui fire process, sharpen to turn Cape to cause remnants remaining to pull in response to the dint, shorten molding tool life span.
Prevent°from measure:Convex mold cohesion transition should even slowly tactful, any knife scars with small service will cause mightiness of should match in response to the dint concentration, its diameter and length-settle a request.
(2)Molding tool material the quality is bad causable of expiration.
The molding tool material internal blemish, such as loose, shrink bore and mix up a composition to be partial to the Xi and carburet distributes not and all, original surface blemish(if oxidize, take off carbon, fold, scar formation etc.) influence steel material function,
A.the admixture Be excessive to cause expiration.
Exist the source of the admixture foot creation crack in the molding tool inner part in the steel, particularly brittleness oxide and Huo sour salt etc., process in the hot pressure in don't take place Su to transform, will cause breaking of brittleness but form tiny crack.At later of visit crack to expand further in hot processing and usage, but cause an opening of molding tool crack.The hole that in addition, in the middle of whetting and paring result in surface because of the peeling off big grain admixture.
B.the surface take off carbon to cause expiration.
Molding tool steel when the hot pressure processes and backs fire, usually because of heat temperature to lead Gao, heat preservation time leads long, but result in steel material surface's taking off carbon, seriously take off a carbolic steel material after the machine processes, sometimes still remain to take off a carbon layer, so in the Cui fire, because of inside outside layer organization of the dissimilarity(the surface takes off the carbon layer as iron cable body, inner part for bead light body) result in organization's changing inconformity, but produce crack.
C.the carburet distribute not to divide and cause expiration.
Molding tool steels, such as Crl2 and Cr112 MoV...etc.'s containing amount of carbon is as higher as metal alloy chemical element and formed many totally crystal carburets, these carburets were forging comparison hour and easily present to take form and net to be partial to Xi and cause Cui fire's often appearing to follow to take the crack that the form carburet distributes, molding tool the crack expand further, but make the molding tool opened to split in the usage expired.
Prevent°from measure:Molding tool when the steel is in the satin Ya should again and again and in many ways to the forging, thus the totally crystal carburet shot in the steel is ground smaller and even, assurance steel carburet asymmetry degree Class request.
(3)The machine of molding tool pluses not appropriate.
The a slices to pare a medium knife scar:The circle Cape part of the type chamber part or convex mold of molding tool is processing in the machine and usually make the part left a knife scar because of entering knife to explore too much and result in severity in response to dint concentrated, be carry on Cui fire processing, in response to mountain concentration the part very easily produce tiny crack.
Prevent°from measure:Together slice to pare in the spare parts thick processed end in, should as far as possible reduce into amount of knife, raise the molding tool surface clean degree.
The b electricity processes to cause expiration.Molding tool while carrying on an electricity to process, in order to turning on electricity to produce a great deal of heat, will make the molding tool processed part to heat to go to very heat degree, make organization occurrence variety, form a so-called electricity to process an excrescent layer, at excrescent layer surface because the heat meltdown happens, then very soon solidify, that assumes white in the microscope bottom and there are many very small cracks in the inner part, under the white layer of the district Cui fire happen, call Cui fire layer, again go toward in because the hot influence weakens, the temperature isn't high, the occurrence returns to fire and calls to return to fire layer.Measurese cross section degree of hardness to distribute:Meltdown again concretion layer, the degree of hardness is very high and reach to a 610~740 HRCs, the thickness is 30 μ ms, Cui fire layer the degree of hardness 400~500 HRCs, thick is 20 μ ms.Return to fire to belong to heat to return to fire, organize softer, the degree of hardness is a 380-400 HRCs, thick is 10 μ ms.
Prevent°from measure:①The method of using the machine cleans and opens a layer often in of then the concretion layer is a particularly tiny view crack;②Processes juniors to go in the electricity a low temperature returns to fire and makes the excrescent layer stability turned, in order to prevent the tiny crack expands.
The c whets to pare to process to result in expiration.When the molding tool type chamber noodles carries on whetting to pare to process, in order to whetting to pare speed to lead greatly, the emery wheel grain spends thin or cool off the condition differ etc. factor influence, all will cause to whet to pare a form song to lead hot or cause surface's softening, the degree of hardness lowers and make the molding tool is in the usage because of wear away severity, or heat in response to dint but the creation whet to pare crack and cause expired in early days.
Prevent°from measure:①The adoption slices to pare the dint strong coarse sand round or glues to knot the emery wheel that sex differs;②Reduce a work piece to enter to the quantity;③Choose a suitable coolant;④Adopt 250~350 ℃ to return to fire after whetting to pare to process, with in addition to whet to pare in response to the dint.
(4)The molding tool heat processing craft is unsuited to proper.
Heat the height, heat preservation of temperature length for time, cool off speed rate of speed etc. the heat processing craft parameter choose not appropriate, will become molding tool expiration factor.
A.heat speed:There is more carbon in the molding tool steel and match a life chemical element, transmit heat sex bad, therefore, heating the speed can not too quick, should be slow-moving the occurrence carrying on, prevent°froming a molding tool transform and open crack.While heating Cui fire in the air stove, it is in bar of to oxidize and take off carbon, the adoption packs protection heating, at this time heat speed should not lead quickly, and deeply the heat should be also slower.Thus, can't produce big heat in response to the dint, more safe.If the molding tool heats speed quickly, deeply hot quick, the outside inside the molding tool produces very big heat in response to the dint.If controling isn't appropriate and produce to transform very easily or crack, have to adopt to prepare hot or reduce to slowly heat acceleration to prevent°fro.
B.oxidize and take off carbolic influence.Molding tool Cui fire is carry on under the heat degree, such as not and strictly control, the form song oxidizes and takes off carbon very easily.Moreover, molding tool surface after taking off carbon, because of inside the outside layer organization appear bigger organization in response to the dint and cause Cui fire in the difference, cooling crack.
Prevent°from measure:Can adopt to pack a protection a processing, fill to defend to oxidize and take off inside the box carbon of fill material.
Third, Cool off conditional influence
Different molding tool material, according to the organization appearance requested, cool off speed is different.To the high metal alloy steel, because of containing a more metal alloy chemical element, Cui deeply sex is higher, can adopt oil cold, empty cold even etc. the heats such as Wen Cui Huo and grade Cui fire etc. handle craft.
First, Molding tool is expired
Cold hot molding tool in the middle of undergoing military service the expired basic form can is divided into:The Su transforms;Wear away;Tired;Split.
(1)The Su transforms.
The Su transforms namely bear carry is bigger than to accept defeat transforming of strength but creation.Fall to sink such as the cave mold appeared chamber, type bore the extension and sharp angle tumble down to sink and the convex mold appears Dun thick, lengthways bent etc..Particularly hot make a molding tool, it works surface and heat material contact, the made chamber surface temperature usually exceeds heat to make the returning of molding tool steel fire temperature, type the wall inside the slot is collapsed under pressure or press a heap because of softening.When the low Cui deeply sexual steel kind was used to a cold Dun mold, molding tool after the Cui fire heats, to inside the bore carried on spraying water cooling to produce a hardening layer.Molding tool while using, such as the cold Dun dint lead greatly, hardening layer underneath of the base anti- press to accept defeat strength not high, the molding tool bore chamber is collapsed under pressure.The molding tool steel accepts defeat strength generally with the content of carbon(c) from the increasing of some metal alloy chemical elementses but go up, in the degree of hardness under the same circumstance, the steel of different chemistry composition has of the anti- press strength different, following 4 kinds of anti-s of steels accept defeat strength while being the steel degree of hardness as 63 HRCs one by one in order in proper order from Gao Dao Di is:The W18 Cr4 V>Cr 12> Cr6 WV>5 CrNiWs.
(2)Wear away expiration.
Wearing away expiration means that bluntness in the blade door turns, the sharp angle changes circle, flat surface the bottom sinks, surface ditch scar, peeling off glue a film.(in the middle of rubbing molding tool work form but glued some Pis to anticipate metal)Moreover, the convex mold is in the work, because of lubricant burnable after convert into high pressure air, carry on to the convex mold surface violent flush, the formation annoys eclipse.
Cold blunt, if carry not and greatly, wear away a type mainly in order to oxidize, wearing away can also match to wear away for biting of a certain degree and be a blade the part change bluntness or blunt press burden a little bit greatly, biting to match a worn circumstance will become serious, but make to wear away speed, the bearing of molding tool steel whets sex to not only be decided by its degree of hardness, but also be decided to the property, size of carburet and distribute with amount, in the molding tool steel, the bearing of high-speed steel and high chrome steel whets sex currently higher.But under the sistuation that exist to there is the carburet that the carburet of severity is partial to Xi or big grain in the steel, these carburets are easily peeling off, but cause to whet a grain to wear away and make to wear away to speed.A little bit lightly cold make a molding tool of the impact of steel(the lamella is blunt to cut, pull to stretch, flection etc.), don't greatly carry a lotus, mainly for quiet wear away.At quiet wear away a condition under, the containing of molding tool steel amount of carbon is many and bear to whet sex big.Under the sistuation that the impact wears away(like cold Dun, cold crowded and hot Duan etc.), the excessive carburet of no help to exaltation bears to whet sex in the molding tool steel, on the contrary because the impact whets a grain to wear away, but lowers to bear to whet sex.
The research expresses that under the sistuation that the impact whets a grain to wear away, the molding tool steel contains amount of carbon with O.6% for upper limit, cold Dun mold under the sistuation that the impact carries a lotus work, if the carburet in the molding tool steel is excessive, the easily solid impact wears away but mountain the surface is peeling off now.These peeling off hard grain sons will become whetting a grain and quickly wear away speed.Hot make the type of molding tool of chamber surface, makes to bear to whet sex to lower because the heat softens, oxidize sheet iron to also have the function to whet to anticipate in addition, there is still heat oxidizing to decay a function in the meantime.
(3)Tired expiration.
Tired characteristic of the expiration:The molding tool some parts has been definitely undergone military service a period and rose small crack, and gradual deeply expand to the Zong, seriously weaken the loading ability of molding tool but cause to split while expanding to the certain size.The tired crack is risen to in response to the dint bigger part, especially in response to dint concentration part(size transition, indentation, knife scar, wear away crack etc.), the fatigue broke a door to divide two parts while splitting, one part forms for the tired crack development of the tired place broken cross section, present shell-like in shape, the tired source is located on shell top.In order to suddenly split, another part presents the whole rough cross section of gravamen.
Make the molding tool taken place the root reason of tired harm for especially the wreath carries a lotus, any can make the surface pulled the factor that enlarges in response to the dint to can accelerate rising of tired crack all.
Cold make a molding tool when the work is under the high hard appearance the molding tool steel has very high accept defeat strength and split a tenacity very lowly.Gao of accept defeat strength to be advantageous to the creation that postpones tired crack, but lowly split a tenacity to make expanding of tired crack the velocity speed to let up with critical length and make the circulating number consumedly shortenned, therefore, cold the tired life span making a molding tool be mainly decided by tired crack to rise time.
Hot make a molding tool generally at in etc. or lower degree of hardness appearance the bottom undergoes military service, the molding tool splits a tenacity compare cold make a molding tool of Gao De Duo, therefore, makes a molding tool in the heat in, the expanding of tired crack speed is lower than cold make a molding tool, the critical length is bigger than cold make a mold, the heat makes the molding tool tired crack of second critical expand a period colder make a mold to grow much, but hot make the molding tool surface is subjected to nasty cold, the nasty heat rises cold hot tired crack very easily, the heat makes the tired crack of molding tool to rise time compare cold make a mold short get many, therefore, many heats make a mold it is mainly tired to split life span to is decided by time that the tired crack expands.
(4)Split expiration.
Split an expired familiar form to have:Collapse blade, Gua Chi, split crack, break, the bulge split etc., the different molding tool splits of the driving force is different.Cold make a molding tool, be subjected to of mainly is a machine function dint.(blunt pressure)The heat makes a mold be subjected to in addition to machine dint, there is also heat in response to the dint and the organization and there are higher many works temperatures that the heats make a molding tools in response to the dint, again the adoption compulsorily cool off, its internal help dint can far far above machine in response to the dint, therefore, many heats make a splitting of mold mainly with internal help dint lead greatly relevant.
The molding tool splits process to have 2 kinds:1 time splits and tired split.1 time splits for the molding tool sometimes at blunt suddenly split while pressing, crack once rising, after then losing is steady and expands.Its main reason overloads for severity or the molding tool material serious frailty turns.(if leading is hot and returns to fire shortage, seriously gather ten in response to the dint and serious metallurgy blemish etc.)
Second, Molding tools lose efficacy reason and prevention measure
(1)The structure design absurdity causes expiration.
Sharp turn Cape(here in response to dint concentrated is higher than mean stress decuple above) and lead greatly cut noodles variety to result in concentrated in response to the dint, usually become many molding tools in early days expired source.And in the hot processing Cui fire process, sharpen to turn Cape to cause remnants remaining to pull in response to the dint, shorten molding tool life span.
Prevent°from measure:Convex mold cohesion transition should even slowly tactful, any knife scars with small service will cause mightiness of should match in response to the dint concentration, its diameter and length-settle a request.
(2)Molding tool material the quality is bad causable of expiration.
The molding tool material internal blemish, such as loose, shrink bore and mix up a composition to be partial to the Xi and carburet distributes not and all, original surface blemish(if oxidize, take off carbon, fold, scar formation etc.) influence steel material function,
A.the admixture Be excessive to cause expiration.
Exist the source of the admixture foot creation crack in the molding tool inner part in the steel, particularly brittleness oxide and Huo sour salt etc., process in the hot pressure in don't take place Su to transform, will cause breaking of brittleness but form tiny crack.At later of visit crack to expand further in hot processing and usage, but cause an opening of molding tool crack.The hole that in addition, in the middle of whetting and paring result in surface because of the peeling off big grain admixture.
B.the surface take off carbon to cause expiration.
Molding tool steel when the hot pressure processes and backs fire, usually because of heat temperature to lead Gao, heat preservation time leads long, but result in steel material surface's taking off carbon, seriously take off a carbolic steel material after the machine processes, sometimes still remain to take off a carbon layer, so in the Cui fire, because of inside outside layer organization of the dissimilarity(the surface takes off the carbon layer as iron cable body, inner part for bead light body) result in organization's changing inconformity, but produce crack.
C.the carburet distribute not to divide and cause expiration.
Molding tool steels, such as Crl2 and Cr112 MoV...etc.'s containing amount of carbon is as higher as metal alloy chemical element and formed many totally crystal carburets, these carburets were forging comparison hour and easily present to take form and net to be partial to Xi and cause Cui fire's often appearing to follow to take the crack that the form carburet distributes, molding tool the crack expand further, but make the molding tool opened to split in the usage expired.
Prevent°from measure:Molding tool when the steel is in the satin Ya should again and again and in many ways to the forging, thus the totally crystal carburet shot in the steel is ground smaller and even, assurance steel carburet asymmetry degree Class request.
(3)The machine of molding tool pluses not appropriate.
The a slices to pare a medium knife scar:The circle Cape part of the type chamber part or convex mold of molding tool is processing in the machine and usually make the part left a knife scar because of entering knife to explore too much and result in severity in response to dint concentrated, be carry on Cui fire processing, in response to mountain concentration the part very easily produce tiny crack.
Prevent°from measure:Together slice to pare in the spare parts thick processed end in, should as far as possible reduce into amount of knife, raise the molding tool surface clean degree.
The b electricity processes to cause expiration.Molding tool while carrying on an electricity to process, in order to turning on electricity to produce a great deal of heat, will make the molding tool processed part to heat to go to very heat degree, make organization occurrence variety, form a so-called electricity to process an excrescent layer, at excrescent layer surface because the heat meltdown happens, then very soon solidify, that assumes white in the microscope bottom and there are many very small cracks in the inner part, under the white layer of the district Cui fire happen, call Cui fire layer, again go toward in because the hot influence weakens, the temperature isn't high, the occurrence returns to fire and calls to return to fire layer.Measurese cross section degree of hardness to distribute:Meltdown again concretion layer, the degree of hardness is very high and reach to a 610~740 HRCs, the thickness is 30 μ ms, Cui fire layer the degree of hardness 400~500 HRCs, thick is 20 μ ms.Return to fire to belong to heat to return to fire, organize softer, the degree of hardness is a 380-400 HRCs, thick is 10 μ ms.
Prevent°from measure:①The method of using the machine cleans and opens a layer often in of then the concretion layer is a particularly tiny view crack;②Processes juniors to go in the electricity a low temperature returns to fire and makes the excrescent layer stability turned, in order to prevent the tiny crack expands.
The c whets to pare to process to result in expiration.When the molding tool type chamber noodles carries on whetting to pare to process, in order to whetting to pare speed to lead greatly, the emery wheel grain spends thin or cool off the condition differ etc. factor influence, all will cause to whet to pare a form song to lead hot or cause surface's softening, the degree of hardness lowers and make the molding tool is in the usage because of wear away severity, or heat in response to dint but the creation whet to pare crack and cause expired in early days.
Prevent°from measure:①The adoption slices to pare the dint strong coarse sand round or glues to knot the emery wheel that sex differs;②Reduce a work piece to enter to the quantity;③Choose a suitable coolant;④Adopt 250~350 ℃ to return to fire after whetting to pare to process, with in addition to whet to pare in response to the dint.
(4)The molding tool heat processing craft is unsuited to proper.
Heat the height, heat preservation of temperature length for time, cool off speed rate of speed etc. the heat processing craft parameter choose not appropriate, will become molding tool expiration factor.
A.heat speed:There is more carbon in the molding tool steel and match a life chemical element, transmit heat sex bad, therefore, heating the speed can not too quick, should be slow-moving the occurrence carrying on, prevent°froming a molding tool transform and open crack.While heating Cui fire in the air stove, it is in bar of to oxidize and take off carbon, the adoption packs protection heating, at this time heat speed should not lead quickly, and deeply the heat should be also slower.Thus, can't produce big heat in response to the dint, more safe.If the molding tool heats speed quickly, deeply hot quick, the outside inside the molding tool produces very big heat in response to the dint.If controling isn't appropriate and produce to transform very easily or crack, have to adopt to prepare hot or reduce to slowly heat acceleration to prevent°fro.
B.oxidize and take off carbolic influence.Molding tool Cui fire is carry on under the heat degree, such as not and strictly control, the form song oxidizes and takes off carbon very easily.Moreover, molding tool surface after taking off carbon, because of inside the outside layer organization appear bigger organization in response to the dint and cause Cui fire in the difference, cooling crack.
Prevent°from measure:Can adopt to pack a protection a processing, fill to defend to oxidize and take off inside the box carbon of fill material.
Third, Cool off conditional influence
Different molding tool material, according to the organization appearance requested, cool off speed is different.To the high metal alloy steel, because of containing a more metal alloy chemical element, Cui deeply sex is higher, can adopt oil cold, empty cold even etc. the heats such as Wen Cui Huo and grade Cui fire etc. handle craft.
