CN104004897A - Method for refining D406A steel welded unit crystalline grains through space temperature gradient thermal treatment - Google Patents
Method for refining D406A steel welded unit crystalline grains through space temperature gradient thermal treatment Download PDFInfo
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Abstract
The invention provides a method for refining D406A steel welded unit crystalline grains through space temperature gradient thermal treatment, and relates to the field of metal thermal treatment, in particular to the method for refining the D406A steel welded unit crystalline grains through the space temperature gradient thermal treatment. The method aims at solving the problem that due to the fact that the grain size is low after thermal treatment is conducted on D406A steel welded units, the comprehensive mechanical property is poor. The method includes the steps of conducting water cooling while conducting temperature-variable circulating quenching thermal treatment on the D406A steel welded units, wherein the welded units are made to be at different temperatures in the length direction in the thermal treatment process from the weld joint area to the base metal area so that a temperature gradient field can be formed. The method is used for refining the D406A steel welded unit crystalline grains.
Description
Technical field
The present invention relates to metal heat treatmet field, particularly a kind of method that adopts room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain.
Background technology
Low-alloy super-strength steel is the one of ultrahigh-strength steel.Because having quite high intensity and certain toughness, alloying element content is low, and heat processing technique is simple, and cost is relatively cheap, and is widely used in the fields such as space flight, aviation and conventional weapon.A kind of good low-alloy super-strength steel that D406A (30Si2MnCrMoVE) Gang Shi China develops voluntarily, is widely used in aerospace flight vehicle metal shell.
Low-temperaturetempering after the prior heat treatment of low-alloy super-strength steel is generally and quenches, these traditional technologys are having both strength and toughness plasticity simultaneously.And in some member use procedures, often to bear larger shock load, as undercarriage, gun barrel and armour plate etc., but can shorten its work-ing life because toughness is not high, or easily brittle rupture occur and affect safety.Simultaneously, due to the particular requirement to material now, particularly for some special structural parts, as different from tissue, the stressed condition of matrix in the welded seam area of welding assembly, prior heat treatment can not make different weave construction states obtain best tissue by thermal treatment, thereby can not obtain best mechanical property, also can make the quality of component and life-span all be subject to corresponding impact, this is again a very adverse influence for the application of ultrahigh-strength steel.In addition, because welding assembly exists and organizes thick defect with the heat affected zone that approaches weld metal zone in weld metal zone, this is having a strong impact on the mechanical property of welding assembly, so also need to carry out grain refining with suitable heat treating method, makes welding assembly reach good comprehensive mechanical performance.
Summary of the invention
The present invention will solve to have that grain fineness number is low causes the poor problem of comprehensive mechanical property after the thermal treatment of existing D406A steel welding assembly, and a kind of method that adopts room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain is provided.
It is to carry out according to the following steps that the present invention adopts the method for room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain:
One, quench for the first time: local heating is carried out in the weld metal zone to D406A steel welding assembly, when heating, the mother metal district of D406A steel welding assembly is carried out to water-cooling, until rising to 920 DEG C from room temperature, the temperature of the weld metal zone of D406A steel welding assembly is incubated, after finishing, insulation stops water-cooling, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the first time; The time of described insulation is definite according to the maximum ga(u)ge of the weld metal zone of D406A steel welding assembly, and the soaking time of every millimeter of thickness is 2min～3min;
Two, quench for the second time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the first time, when heating, the mother metal district of the welding assembly after quenching is for the first time carried out to water-cooling, the temperature of the weld metal zone of the welding assembly after quenching is for the first time incubated from room temperature rises to 900 DEG C, after finishing, insulation stops water-cooling, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the second time; The time of described insulation is definite according to the maximum ga(u)ge of the weld metal zone of the welding assembly after quenching for the first time, and the soaking time of every millimeter of thickness is 2min～3min;
Three, quench for the third time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the second time, when heating, the mother metal district of the welding assembly after quenching is for the second time carried out to water-cooling, the temperature of the weld metal zone of the welding assembly after quenching is for the second time incubated from room temperature rises to 880 DEG C, after finishing, insulation stops water-cooling, then carry out oil quenchinng to room temperature, obtain the D406A steel welding assembly of grain refining; The time of described insulation is definite according to the maximum ga(u)ge of the weld metal zone of the welding assembly after quenching for the second time, and the soaking time of every millimeter of thickness is 2min～3min.
The principle of the invention: the present invention adopts the weld metal zone local heating to D406A steel welding assembly and adds the method for water-cooling, make welding assembly from weld metal zone to mother metal district formation temperature gradient along its length, this be because, the tissue of welding assembly be inhomogeneous be the tissue difference in each region, particularly, at the thick martensite of being organized as of weld metal zone, and heat affected zone organize also as martensite, but organize tiny a little compared with weld metal zone, evenly, the tissue in mother metal district is more tiny, granular pearlite uniformly, like this, weld metal zone needs higher Heating temperature to quench, so that very inhomogeneous martensitic stucture becomes even, heat affected zone does not need so high Heating temperature.If there is no thermograde, the Heating temperature of heat affected zone and weld metal zone is the same, and the crystal grain of heat affected zone can be grown up to some extent due to the Heating temperature compared with high so, and the grain refining effect after circulating quenching will weaken so.For mother metal district, tissue own is just very tiny, even, does not need quench hot to make tissue become even completely.The existence due to thermograde equally, make the temperature in mother metal district below the transformation temperature of austenitic transformation, so just be equivalent to just not quench in mother metal district at all, also avoided the increase of the welding assembly unrelieved stress causing due to quenching, improved plasticity and the toughness of welding assembly.The thermal treatment of room temps gradient is except making welding assembly from weld metal zone to mother metal district along its length formation temperature gradient, also comprising the processing of member being carried out to alternating temperature circulating quenching, also can crystal grain thinning in making microstructure homogenization, this is because in circulating quenching process, it is austenite that welding assembly is experiencing from martensitic transformation repeatedly, then is martensitic process by austenitic transformation.While reheating each time, tiny particulate state austenite crystal first can be at original austenite crystal prevention, martensite packets boundary forming core, because these position energy are high, be easy to forming core, will obtain tiny tissue by cooling rapidly before not growing up newly-generated austenite.While heating, just there have been more interfaces that can forming core so next time.And when quenching each time, because martensitic transformation is a shear process, in transition process, produce a large amount of defects, as dislocation, fault, twin etc., like this upper while once heating these defects can be inherited, defective locations energy is high, easily forming core, a large amount of defects has also increased position that can forming core, and these all contribute to obtain tiny tissue after heating quenching.Circulate repeatedly according to such principle, just can obtain the crystal grain less, more more than last size.In circulating quenching process, rear primary quenching than the front quenching temperature major cause that decreases is, at martensite in austenite circulating phase-change process, the high-octane defect increasing in martensitic transformation process that reverse has become austenite heredity, motivating force when these energy are just converted into new austenite recrystallization and storage energy.Like this through a circulating quenching, defect concentration will increase, motivating force when austenite forming core crystallization next time also can increase thereupon, high owing to storing can be than last forming core time like this, just do not need the Heating temperature equally high with last crystallization that energy is provided, if adopt same temperature, unnecessary energy will impel newly-generated grain growth, therefore in order to obtain tiny crystal grain, should reduce Heating temperature.
The invention has the beneficial effects as follows:
The present invention can make weld metal zone and the heat affected zone grain refining of D406A steel welding assembly effectively, the weld metal zone of general D406A steel welding assembly after welding is organized as thick dendritic crystalline substance, even cannot measure its grain fineness number, the grain fineness number of heat affected zone is only 2～3 grades, and adopted after thermal treatment of the present invention, the grain fineness number of weld metal zone and heat affected zone has reached respectively 8 grades and 9 grades, significantly refinement crystal grain.Crystal grain obtains after refinement, the comprehensive mechanical property of welding assembly can be improved, the tensile strength of general D406A steel welding assembly tempering heat treatment after traditional quenching is about 1700Mpa, unit elongation is below 8%, and adopted after thermal treatment of the present invention, the tensile strength of welding assembly remains unchanged substantially, but unit elongation has but brought up to 12%, in the situation that not reducing, intensity improves significantly plasticity, realize well the combination of highly malleablized, improved the comprehensive mechanical property of welding assembly.In addition, the inventive method is simple, realizes cost low, and result of use is good.
Brief description of the drawings
Fig. 1 is the microstructure picture of the weld metal zone of the D406A steel welding assembly of the grain refining that obtains of embodiment mono-; Fig. 2 is the microstructure picture of the heat affected zone of the D406A steel welding assembly of the grain refining that obtains of embodiment mono-; Fig. 3 is the microstructure picture in the mother metal district of the D406A steel welding assembly of the grain refining that obtains of embodiment mono-; Fig. 4 is the temperature gradient distribution curve that in embodiment bis-, on fine strip shape D406A steel welding assembly, some test point record; Fig. 5 is the microstructure picture of the weld metal zone of the fine strip shape D406A steel welding assembly after the anneal that obtains of embodiment tri-; Fig. 6 is the microstructure picture of the heat affected zone of the fine strip shape D406A steel welding assembly after the anneal that obtains of embodiment tri-; Fig. 7 is the microstructure picture in the mother metal district of the fine strip shape D406A steel welding assembly after the anneal that obtains of embodiment tri-; Fig. 8 is the microstructure picture of the weld metal zone of the D406A steel welding assembly of the grain refining that obtains of embodiment tetra-; Fig. 9 is the microstructure picture of the heat affected zone of the D406A steel welding assembly of the grain refining that obtains of embodiment tetra-; Figure 10 is the microstructure picture in the mother metal district of the D406A steel welding assembly of the grain refining that obtains of embodiment tetra-; Figure 11 is the microstructure picture of the weld metal zone of the D406A steel welding assembly of the grain refining that obtains of embodiment five; Figure 12 is the microstructure picture of the heat affected zone of the D406A steel welding assembly of the grain refining that obtains of embodiment five; Figure 13 is the microstructure picture in the mother metal district of the D406A steel welding assembly of the grain refining that obtains of embodiment five.
Embodiment
Embodiment one: it is to carry out according to the following steps that present embodiment adopts the method for room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain:
One, quench for the first time: local heating is carried out in the weld metal zone to D406A steel welding assembly, when heating, the mother metal district of D406A steel welding assembly is carried out to water-cooling, until rising to 920 DEG C from room temperature, the temperature of the weld metal zone of D406A steel welding assembly is incubated, after finishing, insulation stops water-cooling, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the first time; The time of described insulation is definite according to the maximum ga(u)ge of the weld metal zone of D406A steel welding assembly, and the soaking time of every millimeter of thickness is 2min～3min;
Two, quench for the second time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the first time, when heating, the mother metal district of the welding assembly after quenching is for the first time carried out to water-cooling, the temperature of the weld metal zone of the welding assembly after quenching is for the first time incubated from room temperature rises to 900 DEG C, after finishing, insulation stops water-cooling, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the second time; The time of described insulation is definite according to the maximum ga(u)ge of the weld metal zone of the welding assembly after quenching for the first time, and the soaking time of every millimeter of thickness is 2min～3min;
Three, quench for the third time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the second time, when heating, the mother metal district of the welding assembly after quenching is for the second time carried out to water-cooling, the temperature of the weld metal zone of the welding assembly after quenching is for the second time incubated from room temperature rises to 880 DEG C, after finishing, insulation stops water-cooling, then carry out oil quenchinng to room temperature, obtain the D406A steel welding assembly of grain refining; The time of described insulation is definite according to the maximum ga(u)ge of the weld metal zone of the welding assembly after quenching for the second time, and the soaking time of every millimeter of thickness is 2min～3min.
Present embodiment principle: present embodiment adopts the weld metal zone local heating to D406A steel welding assembly and adds the method for water-cooling, make welding assembly from weld metal zone to mother metal district formation temperature gradient along its length, this be because, the tissue of welding assembly be inhomogeneous be the tissue difference in each region, particularly, at the thick martensite of being organized as of weld metal zone, and heat affected zone organize also as martensite, but organize tiny a little compared with weld metal zone, evenly, the tissue in mother metal district is more tiny, granular pearlite uniformly, like this, weld metal zone needs higher Heating temperature to quench, so that very inhomogeneous martensitic stucture becomes even, heat affected zone does not need so high Heating temperature.If there is no thermograde, the Heating temperature of heat affected zone and weld metal zone is the same, and the crystal grain of heat affected zone can be grown up to some extent due to the Heating temperature compared with high so, and the grain refining effect after circulating quenching will weaken so.For mother metal district, tissue own is just very tiny, even, does not need quench hot to make tissue become even completely.The existence due to thermograde equally, make the temperature in mother metal district below the transformation temperature of austenitic transformation, so just be equivalent to just not quench in mother metal district at all, also avoided the increase of the welding assembly unrelieved stress causing due to quenching, improved plasticity and the toughness of welding assembly.The thermal treatment of room temps gradient is except making welding assembly from weld metal zone to mother metal district along its length formation temperature gradient, also comprising the processing of member being carried out to alternating temperature circulating quenching, also can crystal grain thinning in making microstructure homogenization, this is because in circulating quenching process, it is austenite that welding assembly is experiencing from martensitic transformation repeatedly, then is martensitic process by austenitic transformation.While reheating each time, tiny particulate state austenite crystal first can be at original austenite crystal prevention, martensite packets boundary forming core, because these position energy are high, be easy to forming core, will obtain tiny tissue by cooling rapidly before not growing up newly-generated austenite.While heating, just there have been more interfaces that can forming core so next time.And when quenching each time, because martensitic transformation is a shear process, in transition process, produce a large amount of defects, as dislocation, fault, twin etc., like this upper while once heating these defects can be inherited, defective locations energy is high, easily forming core, a large amount of defects has also increased position that can forming core, and these all contribute to obtain tiny tissue after heating quenching.Circulate repeatedly according to such principle, just can obtain the crystal grain less, more more than last size.In circulating quenching process, rear primary quenching than the front quenching temperature major cause that decreases is, at martensite in austenite circulating phase-change process, the high-octane defect increasing in martensitic transformation process that reverse has become austenite heredity, motivating force when these energy are just converted into new austenite recrystallization and storage energy.Like this through a circulating quenching, defect concentration will increase, motivating force when austenite forming core crystallization next time also can increase thereupon, high owing to storing can be than last forming core time like this, just do not need the Heating temperature equally high with last crystallization that energy is provided, if adopt same temperature, unnecessary energy will impel newly-generated grain growth, therefore in order to obtain tiny crystal grain, should reduce Heating temperature.
Present embodiment can make weld metal zone and the heat affected zone grain refining of D406A steel welding assembly effectively, the weld metal zone of general D406A steel welding assembly after welding is organized as thick dendritic crystalline substance, even cannot measure its grain fineness number, the grain fineness number of heat affected zone is only 2～3 grades, and adopted after thermal treatment of the present invention, the grain fineness number of weld metal zone and heat affected zone has reached respectively 8 grades and 9 grades, significantly refinement crystal grain.Crystal grain obtains after refinement, the comprehensive mechanical property of welding assembly can be improved, the tensile strength of general D406A steel welding assembly tempering heat treatment after traditional quenching is about 1700Mpa, unit elongation is below 8%, and adopted after thermal treatment of the present invention, the tensile strength of welding assembly remains unchanged substantially, but unit elongation has but brought up to 12%, in the situation that not reducing, intensity improves significantly plasticity, realize well the combination of highly malleablized, improved the comprehensive mechanical property of welding assembly.In addition, the inventive method is simple, realizes cost low, and result of use is good.
Embodiment two: present embodiment is different from embodiment one: the steel of D406A described in step 1 welding assembly is fine strip shape.Other is identical with embodiment one.
Embodiment three: present embodiment is different from embodiment one or two: described in step 1, in oil quenchinng, oil used is No. 20 machine oil.Other is identical with embodiment one or two.
Embodiment four: present embodiment is different from embodiment one to three: described in step 2, in oil quenchinng, oil used is No. 20 machine oil.Other is identical with embodiment one to three.
Embodiment five: present embodiment is different from one of embodiment one to four: described in step 3, in oil quenchinng, oil used is No. 20 machine oil.Other is identical with one of embodiment one to four.
Embodiment six: present embodiment is different from one of embodiment one to five: the time being incubated described in step 1 is definite according to the maximum ga(u)ge of the weld metal zone of D406A steel welding assembly, and the soaking time of every millimeter of thickness is 2.5min.Other is identical with one of embodiment one to five.
Embodiment seven: present embodiment is different from one of embodiment one to six: the time being incubated described in step 2 is definite according to the maximum ga(u)ge of the weld metal zone of D406A steel welding assembly, and the soaking time of every millimeter of thickness is 2.5min.Other is identical with one of embodiment one to six.
Embodiment eight: present embodiment is different from one of embodiment one to seven: the time being incubated described in step 3 is definite according to the maximum ga(u)ge of the weld metal zone of D406A steel welding assembly, and the soaking time of every millimeter of thickness is 2.5min.Other is identical with one of embodiment one to seven.
Verify beneficial effect of the present invention by following examples:
Embodiment mono-: adopting the method for room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain is to carry out according to the following steps:
One, quench for the first time: local heating is carried out in the weld metal zone to the fine strip shape D406A steel welding assembly that is of a size of 100mm × 10mm × 3.5mm, when heating, the mother metal district of D406A steel welding assembly is carried out to water-cooling, until rising to 920 DEG C from room temperature, the temperature of the weld metal zone of D406A steel welding assembly is incubated, after finishing, insulation stops water-cooling, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the first time; The time of described insulation is 10min;
Two, quench for the second time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the first time, when heating, the mother metal district of the welding assembly after quenching is for the first time carried out to water-cooling, the temperature of the weld metal zone of the welding assembly after quenching is for the first time incubated from room temperature rises to 900 DEG C, after finishing, insulation stops water-cooling, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the second time; The time of described insulation is 10min;
Three, quench for the third time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the second time, when heating, the mother metal district of the welding assembly after quenching is for the second time carried out to water-cooling, the temperature of the weld metal zone of the welding assembly after quenching is for the second time incubated from room temperature rises to 880 DEG C, after finishing, insulation stops water-cooling, then carry out oil quenchinng to room temperature, obtain the D406A steel welding assembly of grain refining; The time of described insulation is 10min.
Fig. 1 is the microstructure picture of the weld metal zone of the D406A steel welding assembly of the grain refining that obtains of embodiment mono-; Fig. 2 is the microstructure picture of the heat affected zone of the D406A steel welding assembly of the grain refining that obtains of embodiment mono-; Fig. 3 is the microstructure picture in the mother metal district of the D406A steel welding assembly of the grain refining that obtains of embodiment mono-; As can be seen from the figure in embodiment mono-, the grain fineness number of the weld metal zone of the D406A steel welding assembly of grain refining is 8 grades, the grain fineness number of the heat affected zone of the D406A steel welding assembly of grain refining in embodiment mono-is 9 grades, and the grain fineness number in the mother metal district of the D406A steel welding assembly of grain refining in embodiment mono-is 10 grades.Table 1 is grain-size and the grain fineness number in the each region of D406A steel welding assembly of the welding assembly after quenching for the first time in embodiment mono-, the welding assembly after quenching for the second time and grain refining; As can be seen from Table 1, after adopting heat treating method of the present invention to heat-treat D406A steel welding assembly, the weld metal zone of D406A steel welding assembly and the grain fineness number of heat affected zone have reached respectively 8 grades and 9 grades, and crystal grain is refinement significantly.So the present invention can make weld metal zone and the heat affected zone grain refining of welding assembly effectively, improve the comprehensive mechanical property of welding assembly.
Welding assembly after welding assembly, quenching for the second time after quenching for the first time in table 1 embodiment mono-and grain refining
Grain-size and the grain fineness number in the each region of D406A steel welding assembly
Embodiment bis-: local heating is carried out in the weld metal zone to the fine strip shape D406A steel welding assembly that is of a size of 100mm × 10mm × 3.5mm, when heating, the mother metal district of D406A steel welding assembly is carried out to water-cooling, until rising to 920 DEG C from room temperature, the temperature of the weld metal zone of D406A steel welding assembly is incubated, the time of insulation is 10min, in insulating process, get several test point along the length direction of fine strip shape D406A steel welding assembly, adopt thermopair to carry out thermometric to several test point.
Fig. 4 is the temperature gradient distribution curve that in embodiment bis-, on fine strip shape D406A steel welding assembly, some test point record, wherein 1 expression austenite transformation temperature in figure, and 2 represent weld metal zones, and 3 represent heat affected zones, and 4 represent mother metal districts; As can be seen from Figure, after water-cooled, D406A steel welding assembly presents larger thermograde.In the scope nearer apart from D406A steel welding assembly weld seam center, (0～5mm) thermograde is more slow, larger in thermograde within the scope of D406A steel welding assembly weld seam center 5～30mm, in the scope away from D406A steel welding assembly weld seam center, (30～50mm) temperature is lower and change little.In D406A steel welding assembly weld metal zone (within the scope of 0～2.5mm) all more than austenite transformation temperature (830 DEG C).Taking apart from the D406A steel welding assembly pitch of weld from 2mm place as example, temperature is 884 DEG C herein.At a little higher than austenite transformation temperature of D406A steel welding assembly heat affected zone (within the scope of 2.5mm～6mm) temperature.Taking apart from the D406A steel welding assembly pitch of weld from 4.5mm place as example, temperature is 848 DEG C herein.In D406A steel welding assembly mother metal district (within the scope of >7mm) temperature lower than austenite transformation temperature.Taking apart from the D406A steel welding assembly pitch of weld from 10mm place as example, temperature is 700 DEG C herein.Away from D406A steel welding assembly weld seam center (within the scope of 30～50mm) temperature far below austenite transformation temperature, and temperature variation is little.Taking apart from the D406A steel welding assembly pitch of weld from 30mm place as example, temperature is 200 DEG C herein.This illustrates under water-cooled condition, each region of D406A steel welding assembly has all obtained required separately suitable Heating temperature, according to the gradient Principles of Heating Processing described in summary of the invention and grain refining principle, under such thermograde, the weld metal zone of D406A steel welding assembly and heat affected zone tissue can become the even while does not cause again coarse grains.
Embodiment tri-: the fine strip shape D406A steel welding assembly that is of a size of 100mm × 10mm × 3.5mm is heated to 650 DEG C with stove in heat treatment furnace, is then incubated 10min, last furnace cooling, obtains the fine strip shape D406A steel welding assembly after anneal.
Fig. 5 is the microstructure picture of the weld metal zone of the fine strip shape D406A steel welding assembly after the anneal that obtains of embodiment tri-; Fig. 6 is the microstructure picture of the heat affected zone of the fine strip shape D406A steel welding assembly after the anneal that obtains of embodiment tri-; Fig. 7 is the microstructure picture in the mother metal district of the fine strip shape D406A steel welding assembly after the anneal that obtains of embodiment tri-; The weld metal zone that can find out the fine strip shape D406A steel welding assembly after anneal from Fig. 5, Fig. 6 and Fig. 7 is organized as thick dendritic crystalline substance, even cannot measure its grain fineness number, the grain fineness number of the heat affected zone of the fine strip shape D406A steel welding assembly after anneal is only 2～3 grades, and the heat affected zone of fine strip shape D406A steel welding assembly after weld metal zone and the anneal of fine strip shape D406A steel welding assembly after anneal organize also extremely inhomogeneously, the grain fineness number in the fine strip shape D406A steel welding assembly mother metal district after anneal is 10 grades.
Embodiment tetra-: one, quenching for the first time: local heating is carried out in the weld metal zone to the fine strip shape D406A steel welding assembly that is of a size of 100mm × 10mm × 3.5mm, until rising to 920 DEG C from room temperature, the temperature of the weld metal zone of D406A steel welding assembly is incubated, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the first time; The time of described insulation is 10min;
Two, quench for the second time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the first time, the temperature of the weld metal zone of the welding assembly after quenching is for the first time incubated from room temperature rises to 920 DEG C, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the second time; The time of described insulation is 10min;
Three, quench for the third time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the second time, the temperature of the weld metal zone of the welding assembly after quenching is for the second time incubated from room temperature rises to 920 DEG C, then carry out oil quenchinng to room temperature, obtain the D406A steel welding assembly of grain refining; The time of described insulation is 10min.
Fig. 8 is the microstructure picture of the weld metal zone of the D406A steel welding assembly of the grain refining that obtains of embodiment tetra-; Fig. 9 is the microstructure picture of the heat affected zone of the D406A steel welding assembly of the grain refining that obtains of embodiment tetra-; Figure 10 is the microstructure picture in the mother metal district of the D406A steel welding assembly of the grain refining that obtains of embodiment tetra-; As can be seen from the figure in embodiment tetra-, the grain fineness number of the weld metal zone of the D406A steel welding assembly of grain refining is 5 grades, the grain fineness number of the heat affected zone of the D406A steel welding assembly of grain refining in embodiment tetra-is 6 grades, and the grain fineness number in the mother metal district of the D406A steel welding assembly of grain refining in embodiment tetra-is 10 grades.
Embodiment five: one, quenching for the first time: local heating is carried out in the weld metal zone to the fine strip shape D406A steel welding assembly that is of a size of 100mm × 10mm × 3.5mm, until rising to 920 DEG C from room temperature, the temperature of the weld metal zone of D406A steel welding assembly is incubated, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the first time; The time of described insulation is 10min;
Two, quench for the second time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the first time, the temperature of the weld metal zone of the welding assembly after quenching is for the first time incubated from room temperature rises to 920 DEG C, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the second time; The time of described insulation is 10min;
Three, quench for the third time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the second time, the temperature of the weld metal zone of the welding assembly after quenching is for the second time incubated from room temperature rises to 920 DEG C, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the third time; The time of described insulation is 10min;
Four, quench for the 4th time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the third time, the temperature of the weld metal zone of the welding assembly after quenching is for the third time incubated from room temperature rises to 920 DEG C, then carry out oil quenchinng to room temperature, obtain the welding assembly after quenching for the 4th time; The time of described insulation is 10min;
Five, quench for the 5th time: local heating is carried out in the weld metal zone of the welding assembly after the 4th time is quenched, rising to 920 DEG C from room temperature, the temperature of the weld metal zone of the welding assembly after the 4th time is quenched is incubated, then carry out oil quenchinng to room temperature, obtain the D406A steel welding assembly of grain refining; The time of described insulation is 10min.
Figure 11 is the microstructure picture of the weld metal zone of the D406A steel welding assembly of the grain refining that obtains of embodiment five; Figure 12 is the microstructure picture of the heat affected zone of the D406A steel welding assembly of the grain refining that obtains of embodiment five; Figure 13 is the microstructure picture in the mother metal district of the D406A steel welding assembly of the grain refining that obtains of embodiment five; As can be seen from the figure in embodiment five, the grain fineness number of the weld metal zone of the D406A steel welding assembly of grain refining is 6 grades, the grain fineness number of the heat affected zone of the D406A steel welding assembly of grain refining in embodiment five is 7 grades, and the grain fineness number in the mother metal district of the D406A steel welding assembly of grain refining in embodiment five is 10 grades.
Claims (8)
1. the method that adopts room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain, is characterized in that adopting the method for room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain is to carry out according to the following steps:
One, quench for the first time: local heating is carried out in the weld metal zone to D406A steel welding assembly, when heating, the mother metal district of D406A steel welding assembly is carried out to water-cooling, until rising to 920 DEG C from room temperature, the temperature of the weld metal zone of D406A steel welding assembly is incubated, after finishing, insulation stops water-cooling, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the first time; The time of described insulation is definite according to the maximum ga(u)ge of the weld metal zone of D406A steel welding assembly, and the soaking time of every millimeter of thickness is 2min～3min;
Two, quench for the second time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the first time, when heating, the mother metal district of the welding assembly after quenching is for the first time carried out to water-cooling, the temperature of the weld metal zone of the welding assembly after quenching is for the first time incubated from room temperature rises to 900 DEG C, after finishing, insulation stops water-cooling, then carry out oil quenchinng to room temperature, the welding assembly after being quenched for the second time; The time of described insulation is definite according to the maximum ga(u)ge of the weld metal zone of the welding assembly after quenching for the first time, and the soaking time of every millimeter of thickness is 2min～3min;
Three, quench for the third time: local heating is carried out in the weld metal zone to the welding assembly after quenching for the second time, when heating, the mother metal district of the welding assembly after quenching is for the second time carried out to water-cooling, the temperature of the weld metal zone of the welding assembly after quenching is for the second time incubated from room temperature rises to 880 DEG C, after finishing, insulation stops water-cooling, then carry out oil quenchinng to room temperature, obtain the D406A steel welding assembly of grain refining; The time of described insulation is definite according to the maximum ga(u)ge of the weld metal zone of the welding assembly after quenching for the second time, and the soaking time of every millimeter of thickness is 2min～3min.
2. the method for the method modified by silver of employing room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain according to claim 1, is characterized in that the steel of D406A described in step 1 welding assembly is fine strip shape.
3. the method for employing room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain according to claim 1, is characterized in that described in step 1 in oil quenchinng that oil used is No. 20 machine oil.
4. the method for employing room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain according to claim 1, is characterized in that described in step 2 in oil quenchinng that oil used is No. 20 machine oil.
5. the method for employing room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain according to claim 1, is characterized in that described in step 3 in oil quenchinng that oil used is No. 20 machine oil.
6. the method for employing room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain according to claim 1, it is characterized in that the time being incubated described in step 1 is definite according to the maximum ga(u)ge of the weld metal zone of D406A steel welding assembly, the soaking time of every millimeter of thickness is 2.5min.
7. the method for employing room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain according to claim 1, it is characterized in that the time being incubated described in step 2 is definite according to the maximum ga(u)ge of the weld metal zone of D406A steel welding assembly, the soaking time of every millimeter of thickness is 2.5min.
8. the method for employing room temps gradient thermal treatment refinement D406A steel welding assembly crystal grain according to claim 1, it is characterized in that the time being incubated described in step 3 is definite according to the maximum ga(u)ge of the weld metal zone of D406A steel welding assembly, the soaking time of every millimeter of thickness is 2.5min.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104726652A (en) * | 2015-04-09 | 2015-06-24 | 哈尔滨工业大学 | Gradient heat treatment method for super-strength steel |
| CN109762965A (en) * | 2019-02-01 | 2019-05-17 | 哈尔滨工业大学（威海） | A kind of continuous online preparation method of ultra-high strength and toughness Mn-B steel construction piece |
| CN112621042A (en) * | 2021-01-11 | 2021-04-09 | 东方电气集团东方锅炉股份有限公司 | Method for manufacturing dissimilar steel welded joint of 2.25Cr1Mo0.25V steel and carbon-manganese low alloy steel |
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| JPS55122631A (en) * | 1979-02-07 | 1980-09-20 | Electric Power Res Inst | Heat treatment method of body with welding joint |
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| JPS55122631A (en) * | 1979-02-07 | 1980-09-20 | Electric Power Res Inst | Heat treatment method of body with welding joint |
Non-Patent Citations (1)
| Title |
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| 古婉力: ""D406A钢焊接构件梯度热处理过程的数值模拟及晶粒细化"", 《中国优秀硕士学位论文全文数据库》, no. 6, 15 June 2014 (2014-06-15) * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104726652A (en) * | 2015-04-09 | 2015-06-24 | 哈尔滨工业大学 | Gradient heat treatment method for super-strength steel |
| CN109762965A (en) * | 2019-02-01 | 2019-05-17 | 哈尔滨工业大学（威海） | A kind of continuous online preparation method of ultra-high strength and toughness Mn-B steel construction piece |
| CN109762965B (en) * | 2019-02-01 | 2024-04-16 | 哈尔滨工业大学（威海） | Continuous online preparation method of Mn-B steel structural part with super high toughness |
| CN112621042A (en) * | 2021-01-11 | 2021-04-09 | 东方电气集团东方锅炉股份有限公司 | Method for manufacturing dissimilar steel welded joint of 2.25Cr1Mo0.25V steel and carbon-manganese low alloy steel |
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Application publication date: 20140827 |