Summary of the invention
Problem to be solved by this invention provides a kind of forging and pressing milling method of large pulley, its objective is the mechanical performance, the reduction manufacturing cost that improve large pulley.
To achieve these goals, the technical scheme that the present invention takes is: the forging and pressing rolling technique of this large pulley that is provided, described large pulley comprises wheel rim, wheel hub, spoke, the excircle of wheel rim is provided with the race of annular, described pulley adopts heat processing technique to obtain the base type before machining, in this technical process, the steel ingot blank of described pulley or continuous casting blank are through the fixed thick sizing of forge hot jumping-up, the first shape of described wheel hub and spoke is by forging die excellent suitability for press forming, the internal circular surfaces of described wheel rim, both ends of the surface, the periphery of wheel rim and the race on the excircle are by the hot rolling roll milling forming.
Described heat processing technique process is once heating shaping in its whole process, its technical process is:
The cutting of step a, blank and heating: adopt special-purpose cutting off machine or large-scale circular saw that the steel ingot or the continuous casting billet of circle are cut the acquisition blank, then place it in and be heated to initial forging temperature in the heating furnace and continue for some time, come out of the stove then;
The fixed thick sizing of step b, jumping-up: the steel billet of heating is placed on the work top of forcing press and carries out jumping-up, realize the fixed thick sizing of steel billet;
Step c, impression: the steel billet that then will decide thick sizing is placed on the hot forged mould, carries out impression on forcing press, realizes the predistribution of metal;
The moulding of steps d, pulley base: the steel billet behind the impression is put into forcing press carry out compression molding, the forging die of this operation comprises by upper and lower shaping mould and moulding ring, realizes the moulding of wheel hub and part spoke, the preformed of wheel bore and wheel rim, and wheel bore is non-through;
Step e, hot rolling spreading: by hot rolling spreading, realize the roll forming of wheel rim, spoke and race, make the designing requirement of its section configuration and size conforms finished product to wheel rim and disc;
Step f, punching and smooth: the pulley base that spreading is rolling is delivered on the forcing press, gross weight to wheel bore carries out punching, make it become through hole, then be placed on again in the hot forged mould and wheel rim and spoke carried out smooth, eliminate the slight twisted phenomena of wheel rim that the pulley base occurs in the operation of rolling;
Step g, cooling and normalizing: the pulley base is transported on the chain-type cooling bed cools off a period of time, put into constant-temperature oven isothermal a period of time, then carry out normalized treatment again, so far the heat processing technique of whole pulley is that die forging, spreading rolling mill practice process finish.
Initial forging temperature among the described step a is 1250 ℃~1320 ℃, and described temperature retention time is 4 hours~4.5 hours.
Forcing press among described step b or step c or the step f is a hydraulic press, and its maximum pressure is 30MN.
Forcing press in the described steps d is a hydraulic press, and its maximum pressure is 80MN.
In the described step g, the temperature of the pulley base that cools off on the process chain-type cooling bed is 600 ℃~620 ℃, and carries out isothermal with same temperature, and isothermal time is 5.5~6.5 hours.
The present invention also provides the hot rolling spreading equipment of middle employing of the forging and pressing rolling technique of described this large pulley, apply to the hot rolling spreading step of above-mentioned technical process, its technical scheme is: described hot rolling spreading equipment is a horizontal hot rolling unit, the hold-down roller that this unit is established a home roll and a pair of symmetrical distribution pressurizes to pulley, race and periphery on shape on the excircle of home roll and the wheel rim excircle adapt, hold-down roller be arranged in wheel rim radially with the interior circle of home roll equidirectional on, wheel rim radially with the home roll rightabout, if the cross roll of a pair of symmetrical distribution pressurizes to pulley, the outer circumferential shape of cross roll and the end face of wheel rim, the shape of inner headed face and spoke junction adapts.
Embrace roll-in to pulley what the described both ends of the surface of described wheel hub were established a pair of symmetrical distribution, the end surface shape of its outer circumferential shape and wheel hub adapts.
The present invention adopts technique scheme, has compared with prior art obtained following effect:
1, use the pulley of die forging, the rolling integral body of spreading, the density height of pulley material, the composition and the texture of metal are even, and the metallic fiber streamline tissue of its spoke, wheel rim and wheel rim well makes the mechanical strength height of pulley, and anti-wear performance is good;
2, be heated evenly with cooling velocity, internal stress is little, and is not yielding;
3, owing to there is not the gusset of disc, make to obtain shape and accurate in size pulley easily in machining that the symmetry of pulley is good, pulley is stressed even during use, and significantly increase service life;
3, owing to there is not the gusset of disc, makes the substance of pulley alleviate, thereby reduced weight and the manufacturing cost and the use cost of apparatus body;
4, the utilization rate of material has had large increase; Because die forging, the rolling whole pulley energy production in enormous quantities, high efficiency of spreading and more accurate manufacturing, wherein most mould can be reused, and this just makes the integrated cost of its each part pulley after making thinner further reduce.
The specific embodiment
The present invention is to provide a kind of forging and pressing rolling technique of large pulley, the processing process schematic diagram that Fig. 1 is adopted for this forging and pressing rolling technique; The present invention also provides the technical scheme of the hot rolling forging equipment that adopts this forging and pressing rolling technique, and Fig. 2 is the structural representation of described hot rolling spreading equipment.
This large pulley 1 comprises wheel rim 2, wheel hub 3, spoke 4, and the excircle of wheel rim 2 is provided with the race 5 of annular, and described pulley 1 adopts heat processing technique to obtain the base type before machining.
The present invention is for the mechanical performance that realizes improving large pulley, the purpose that reduces manufacturing cost, the technical scheme of being taked is: in the process of this technology, the steel ingot blank of described pulley 1 or continuous casting blank are through the fixed thick sizing of forge hot jumping-up, the first shape of described wheel hub 3 and spoke 4 is by the forging die excellent suitability for press forming, and the periphery of the internal circular surfaces of described wheel rim 2, both ends of the surface, wheel rim 2 and the race on the excircle 5 are by the hot rolling roll milling forming.
Use the pulley of die forging, the rolling integral body of spreading, the density height of pulley material, the composition and the texture of metal are even, and the metallic fiber streamline tissue of its spoke 4, wheel rim 2 and wheel rim well makes the mechanical strength height of pulley, and anti-wear performance is good; It is even with cooling velocity to be heated, and internal stress is little, not yielding; Owing to there is not the gusset of disc, make in machining, to obtain shape and accurate in size pulley easily, the symmetry of pulley is good, and pulley is stressed even during use, and significantly increase service life; In addition, owing to there is not the gusset of disc, makes the substance of pulley alleviate, thereby reduced weight and the manufacturing cost and the use cost of apparatus body; Simultaneously, the utilization rate of material has had large increase; Because the rolling whole pulley of die forging, spreading can production in enormous quantities, high efficiency and more accurate the manufacturing, wherein most mould can also be reused, this just makes the integrated cost of its each part pulley after making thinner will significantly be lower than casting pulley, welded pulley, and very strong competitive advantage is arranged on market.
Below the formation of technical conceive of the present invention is briefly introduced:
The exploitation of the pulley production technology of die forging, the rolling integral body of spreading is to be based upon on the basis of the manufacturing process of the train wheel of railway, therefore the production process equipment of pulley just is to use the production process equipment of train wheel, but the production technology of pulley has its particularity:
1, pulley has that hub diameter is big, the wheel rim height is little, disc is thin and characteristics such as area is big.Generally between 70~100mm, the wheel rim height H of train wheel then is generally between 125~140mm the wheel rim height H of pulley; Generally between 16~28mm, the web thickness S of train wheel then is generally between 19~30mm the web thickness S of pulley, and the maximum that has reaches 40mm.
Therefore, because above-mentioned difference, the blank D/H value of pulley is bigger than the D/H value of train wheel, this just means the blank with respect to train wheel, and the blank of pulley will " approach ", when its forging and pressing and spreading are rolling, it is big that the resistance of deformation of wheel blank is wanted, the pulley of especially production major diameter specification; And when selecting structural alloy steel for use, during as 35CrMo, the difficulty of its production will be much bigger.
2, train wheel circular rim shows as the single-wheel edge, and the wheel rim 2 of pulley 1 shows as the two-wheel edge; For the special equipment of producing train wheel, rolling two-wheel edge not only in technological design, still in practical operation, exists certain technical difficulty really.
Pulley base of the present invention has groove one corresponding to the outer diametric plane of the tread of train wheel, and promptly race 5.Therefore, accordingly, at flange of rolled surface increase of roll; Use this improving one's methods, make stably to enter rolling groove through the blank after the forging and pressing; It has not only overcome the moving and swing of string up and down when rolling, reduced the difficulty of rolling operation, improved production efficiency effectively, and this groove just, to forming metallic fiber streamline tissue, the mechanical strength that improves wheel rim 2 and race 5 plays extraordinary effect, can regard the wheel rim 2 to pulley 1, the preformed of race 5 in addition as, has further reduced machine-finish allowance.
Below machining process of the present invention is described in detail.As shown in Figure 1, described heat processing technique process is once heating shaping in its whole process, and its technical process is:
The cutting of step a, blank and heating:
Weight according to the pulley base adds the punching recess of wheel hub sky and the scaling loss of heating, draws required cutting stock weight, and burn out rate is by 3%; Cutting off machine that employing is special-purpose or large-scale circular saw cut the acquisition blank to the steel ingot or the continuous casting billet of circle.Then place it in the heating furnace, in heating furnace, be heated to initial forging temperature and continue for some time, come out of the stove then.
Described initial forging temperature can be in 1250 ℃~1320 ℃ scopes, and described heating and duration are 4 hours~4.5 hours.Best initial forging temperature is 1280 ℃.Owing to be a pyrogene type, the heating-up temperature formulation is higher.Be not less than heat time heating time and can come out of the stove in 4 hours.
Step b, the fixed thick sizing of jumping-up:
The steel billet of heating is placed on the work top of forcing press carries out jumping-up, realize the fixed thick sizing of steel billet.
Step c, impression:
The steel billet of fixed thick sizing is placed on the hot forged mould of a special use, on forcing press, carries out impression, realize the predistribution of metal.Described forcing press is a hydraulic press, and its maximum pressure is 30MN.
The moulding of steps d, pulley base:
Steel billet behind the impression is put into forcing press carry out compression molding, the forging die of this operation comprises by upper and lower shaping mould and moulding ring, realizes the moulding of wheel hub 3 and part spoke 4, the preformed of wheel hub 3 holes and wheel rim 2, and wheel bore is non-through.Described forcing press is a hydraulic press, and its maximum pressure is 80MN.
This step mainly is the hub portion forging forming with pulley, and the spoke 4 of pulley 1 is the part forging forming, and wheel rim 2 parts are then carried out preform, and qualified blank is provided for the spreading of back is rolling.
Step e, hot rolling spreading:
By hot rolling spreading to wheel rim 2 and spoke 4, realize the roll forming of wheel rim 2, spoke 4 and race 5, make the designing requirement of its section configuration and size conforms finished product; And realize that hole enlargement makes that the radial dimension of its wheel blank is more accurate.Because pulley base axial dimension is less, i.e. D/H〉〉 1, common contour forging technique need add the forcing press of large-tonnage to be realized, and just can utilize existing hydraulic die press to carry out compression molding by rolling hole enlargement; The rolling hole enlargement amount of pulley base is bigger, calculates with the internal diameter of wheel blank, generally is 150 to 200mm; Wheel rim axially depress deflection 8mm.
This step is with the spoke 4 of pulley 1, wheel rim 2 final spreading roll formings, and makes its final size requirement that meets wheel blank, as the spoke 4 of pulley 1 and the gauge of wheel rim 2, the outside dimension of pulley 1, and the internal diameter size of wheel rim 2 etc.
Step f, punching and smooth:
The pulley base that spreading is rolling is delivered on the forcing press, gross weight to wheel hub 3 holes carries out punching, make it become through hole, then be placed in the special-purpose hot forged mould of a cover wheel rim 2 and spoke 4 are carried out smoothly again, eliminate the slight wheel rim twisted phenomena that the pulley base occurs in the operation of rolling.Described forcing press is a hydraulic press, and its maximum pressure is 30MN.
Step g, cooling and normalizing:,
The pulley base is transported on the chain-type cooling bed cools off a period of time, put into constant-temperature oven isothermal a period of time, then carry out normalized treatment again, the hot procedure of so far whole pulley 1 is that the rolling thermal deformation machining process of die forging, spreading finishes.The temperature of the pulley base that cools off on the process chain-type cooling bed is 600 ℃~620 ℃, and carries out isothermal with same temperature, and isothermal time is 5.5~6.5 hours.The best is cold to be 600 ℃; Best isothermal time is 6 hours.
Along with continuous exploitation, the kind and the specification of pulley also increase day by day, at present kind surplus in the of existing nearly 60; Pulley scope that can the rolling integral body of spreading is described with the race diameter of pulley, and its specification reaches 700~1020mm, and with the reached 1152mm of wheel rim top end diameter maximum.
The present invention also provides the hot rolling spreading equipment of middle employing of the forging and pressing rolling technique of described this large pulley, apply to the hot rolling spreading step of above-mentioned technical process, its technical scheme is: as shown in Figure 2, described hot rolling spreading equipment is a horizontal hot rolling unit, this unit is established the hold-down roller of a home roll 6 and a pair of symmetrical distribution to pulley 1 pressurization, race 5 and periphery on shape on the excircle of home roll 6 and wheel rim 2 excircles adapt, hold-down roller be arranged in wheel rim 2 radially with the interior circle of home roll 6 equidirectionals on, wheel rim 2 radially with home roll 6 rightabouts, if the cross roll of a pair of symmetrical distribution 7 is to pulley 1 pressurization, the end face of the outer circumferential shape of cross roll 7 and wheel rim 2, the shape of inner headed face and spoke 4 junctions adapts.
Embrace roll-in to pulley 1 what described wheel hub 3 described both ends of the surface were established a pair of symmetrical distribution, the end surface shape of its outer circumferential shape and wheel hub 3 adapts.
Following table is the comparison of the rolling whole pulley of spreading of the present invention with the performance parameter of casting pulley, welded pulley:
Annotate: the material of forging and pressing is a normalized condition.
From the data of above table, the rolling whole pulley of spreading has very good mechanical performance, is used for more difficult to machine material.Under equal condition, in design, can further reduce the volume at some position of pulley, reducing the substance of pulley 1, as the width of the diameter of wheel hub 3, wheel rim 2 and thickness etc.
In conjunction with the accompanying drawings the present invention has been carried out exemplary description above; obviously specific implementation of the present invention is not subjected to the restriction of aforesaid way; as long as the various improvement of having adopted method design of the present invention and technical scheme to carry out; or design of the present invention and technical scheme are directly applied to other occasion without improving, all within protection scope of the present invention.