CN101085500A - Preparation method for railway freight car coupler tail frame integral forging - Google Patents

Abstract

The high strength alloy steel blank is made through blank making, casting, rectifying, cutting, machining, heat treatment, pill thrusting, and it excels with greatly reduced defects rate, improved in comprehensive feature, doubly increased in part strength and durability. The anti stretch strength reaches 850N/mm2. The impact power Akvj reaches over 27. Through static charge testing, stresses for all the parts are within the allowable scope, increasing fatigue 80%, and durability two times.

Description

The preparation method of railway freight car coupler tail frame integral forging

Technical field

The present invention relates to the railway freight car coupler tail frame that former casting technique is produced, under the prerequisite that does not change function of use, use the method for solid forging instead.

Background technology

Hook tail frame is a key components and parts in the railway vehicle coupler buffer unit, directly finishes the transmission of longitudinal force between the vehicle.The hook tail frame that uses on the past rolling stock is a steel-casting always.Because the inevitable pore of steel-casting, be mingled with, defective such as shrinkage porosite, intensity is difficult to improve.In recent years, the defective that transport capacity enforcement is raised speed because railway is for improving, there is casting hook tail frame in heavy duty has exposed, in use too early appearance fatigue crack, and the brisement accident takes place frequently, bring potential safety hazard to railway transportation, be difficult to adapt to the safety of railway transportation needs.Though know the good product quality of forging effect than casting perfectly well, because the shape of hook tail frame own is the sealing frame type of a hollow, adopting to forge has very big difficulty.

Summary of the invention

The objective of the invention is low for the cast steel hook tail frame intensity that overcomes present use, fatigue life short, problems such as crackle, fracture take place in the utilization process often, provide a kind of employing novel high-strength steel alloy steel billet, by the preparation method that base, forging, shaping, cutting, machine add, operation such as heat treatment, ball blast is finished railway freight car coupler tail frame integral forging.

The preparation method of railway freight car coupler tail frame integral forging of the present invention mainly comprises the steps:

(1) select new material for use: forging hook tail frame will be selected the superior alloy steel steel billet for use, new material will with the cast steel material intensity of present use quite or be higher than cast steel material, as select the 35CrMo milling round steel for use;

(2) accurately calculate material and blanking: it is heavy accurately to calculate material, avoids die cavity to be not fully filled or does not lean on;

(3) base: the round base heating back after the blanking forges on swage block with the above forging hammer of 5T, makes round base preliminary deformation, obtains approaching to give the rectangle blank of forging die cavity;

(4) give forging: the blank that makes is hit preliminarily forming with giving forging mould on large-scale friction press;

(5) finish-forging: put into the finish-forging mould after the forging heating after the forging and forge (generally hitting three shapings) giving once more with large-scale friction press, the design of forging mold is the key of a key, help metal flow, die cavity can be full of, and does not produce folding phenomenon;

(6) cut edge: cut overlap on the forging with large-scale bead cutter and shear mould;

(7) punching the wad hole: wash away the middle excess stock of forging with large-scale friction press and perforating die and make the framework hollow forming;

(8) shaping: with the shaping mold forging is carried out shaping and eliminate the forging distortion that produces owing to operations such as side cut, punching recesses;

(9) ball blast: remove the forging surface scale with special equipment;

(10) go out the frame mouth and reserve allowance with the imitative type cutter cuts of flame;

(11) go out pin-and-hole with the imitative type cutter cuts of flame;

(12) machining: to by forging and cutting does not reach the place of drawing requirement and cutting heat affected area and reaches with the way of machining or remove;

(13) heat treatment: forging is heat-treated the comprehensive mechanical performance of giving full play to steel alloy with the special specification of heat treatment of formulating;

(14) ball blast: surface peening improves the fatigue strength of hook tail frame;

(15) flaw detection.

Beneficial effect:

Use the forging in the present technique invention and process whole hook tail frame and following outstanding advantage is arranged: owing to adopt high-intensity its latent defect of steel alloy stocking to significantly reduce than steel-casting than casting hook tail frame, comprehensive mechanical performance improves, and by forging, press secondary operations can make hook tail frame material form full fibr tissue the intensity of part and service life is significantly improved.Solid forging hook tail frame forges with combined type and compares, and globality is strong, material property is consistent, so hook tail frame each several part intensity can be guaranteed.And combined hook tail frame is to be welded by two connecting plates and the deckle board after bending, and weld seam exists defective to become weak link as founding materials easily, cracks so that fracture at the weld seam position in the utilization.

The present invention can reach 850N/mm through its tensile strength of evidence ²Ballistic work AkvJ (test temperature-40 ℃) can reach more than 27.Through static load test, each position stress value improves 80% all in permissible range as fatigue life ratio casting hook tail frame; Life-span is improved 2 times.

Description of drawings

Fig. 1 is a process chart of the present invention;

Fig. 2 is blanking figure of the present invention;

Fig. 3 is base figure of the present invention;

Fig. 4 is the forging figure that gives of the present invention;

Fig. 5 is finish-forging of the present invention, side cut, punching figure;

Fig. 6 is integer of the present invention, cutting drawing;

Fig. 7 is a stereogram of the present invention.

The specific embodiment

Referring to accompanying drawing, existing be set at hook tail frame overall dimensions: it is as follows that length 932mm, width 200mm, height 366mm, deckle board thickness 28mm are that example is further described:

(1) adopt sawing machine to see Fig. 2 by process blanking (φ 185mm circle guiding principle);

(2) base: forging stock is the round steel heating with blanking, uses the swage block open die forging then on 5 tons of satin hammers, is swaged into and gives the similar first base of forging blank shape, the fine or not quality that directly influences rough forging of first base, first base profile such as Fig. 3;

(3) give forging: need forging forces to reach 8000 ton large-scale friction presses with giving the forging die forging because satin spare size and weight reach 150 kilograms more greatly, after the moulding as Fig. 4;

(4) finish-forging

Put into the finish-forging mould after forging after the forging heats once more and forge after (generally hitting three shapings) moulding as Fig. 5 giving with large-scale 8000 tons of friction presses;

The design of finish-forging forging mold is the key of a key, help metal flow, and die cavity can be full of, and does not produce folding phenomenon;

(5) cut edge: cut overlap on the forging with large-scale 1250 tons of bead cutters and shaving die;

(6) punching the wad hole: wash away in the middle of the forging excess stock with large-scale friction press and perforating die and make behind the framework hollow forming as Fig. 6 (C);

(7) shaping

With shaping mould and special tooling, there is fixed die (straightening die) centre, about template is arranged, afterbody has and pushes up after correcting mould, about and afterbody promote clamping with an oil cylinder respectively, finish the body heat shaping of hook tail circle such as Fig. 6;

(8) ball blast: remove the forging surface scale with special equipment and be beneficial to machining;

(9) cutting: go out the frame mouth and reserve allowance such as Fig. 5 (B) with the imitative type cutter cuts of oxycetylene flame;

And cut out pin-and-hole such as Fig. 6 (E) but because the precision of cutting is not high, next step will reach the figure paper size and remove the heat affected area by machining to have the heat affected area simultaneously;

(10) machining: processes such as employing is milled, brill reach the drawing dimensional requirement and remove the heat affected area;

(11) heat treatment: with the special specification of heat treatment of formulating forging is carried out modified heat treatment, give full play to the comprehensive mechanical performance of 35CrMo steel alloy;

(12) ball blast: use shot-blasting machine, the shot of selecting 1-1.5mm for use is thrown hook tail frame and is beaten, and strengthens the fatigue strength that hook tail frame table face improves hook tail frame;

(13) flaw detection: hook tail frame table face is detected a flaw with large-scale professional magnaflux.

With above-mentioned process produced hook tail frame such as Fig. 7.

Claims (1)

1, a kind of preparation method of railway freight car coupler tail frame integral forging comprises the steps:

(1) select new material for use: forging hook tail frame will be selected the superior alloy steel steel billet for use, new material will with the cast steel material intensity of present use quite or be higher than cast steel material, as select the 35CrMo milling round steel for use;

(2) accurately calculate material and blanking: it is heavy accurately to calculate material, avoids die cavity to be not fully filled or does not lean on;

(3) base: the round base heating back after the blanking forges on swage block with the above forging hammer of 5T, makes round base preliminary deformation, obtains approaching to give the rectangle blank of forging die cavity;

(4) give forging: the blank that makes is hit preliminarily forming with giving forging mould on large-scale friction press;

(5) finish-forging: put into the finish-forging mould after the forging heating after the forging and forge (generally hitting three shapings) giving once more with large-scale friction press, the design of forging mold is the key of a key, help metal flow, die cavity can be full of, and does not produce folding phenomenon;

(6) cut edge: cut overlap on the forging with large-scale bead cutter and shear mould;

(7) punching the wad hole: wash away the middle excess stock of forging with large-scale friction press and perforating die and make the framework hollow forming;

(8) shaping: with the shaping mold forging is carried out shaping and eliminate the forging distortion that produces owing to operations such as side cut, punching recesses;

(9) ball blast: remove the forging surface scale with special equipment;

(10) go out the frame mouth and reserve allowance with the imitative type cutter cuts of flame;

(11) go out pin-and-hole with the imitative type cutter cuts of flame;

(12) machining: to by forging and cutting does not reach the place of drawing requirement and cutting heat affected area and reaches with the way of machining or remove;

(13) heat treatment: forging is heat-treated the comprehensive mechanical performance of giving full play to steel alloy with the special specification of heat treatment of formulating;

(14) ball blast: surface peening improves the fatigue strength of hook tail frame;

(15) flaw detection.

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