CN104624893A

CN104624893A - Forging forming method of large marine crank

Info

Publication number: CN104624893A
Application number: CN201510084155.2A
Authority: CN
Inventors: 冯津赤; 杨万彪; 李耀军; 张俊彦; 周宝华; 白冰
Original assignee: CERI YINGKOU EQUIPMENT DEVELOPMENT AND MANUFACTURING Co Ltd
Current assignee: CERI YINGKOU EQUIPMENT DEVELOPMENT AND MANUFACTURING Co Ltd
Priority date: 2015-02-16
Filing date: 2015-02-16
Publication date: 2015-05-20
Anticipated expiration: 2035-02-16
Also published as: CN104624893B

Abstract

The invention provides a forging forming method of a large marine crank. The forging forming method includes the steps of steel ingot calculating, upset forging, rough machining, compression bending, pressing and shaping after demoulding and heat treatment. When a forged piece of the crank is subjected to rough machining, the shaft part in the middle of the crank is preferably directly machined into a cylindrical shape, crank arms on two sides are machined into tabulate shapes to have machining allowance reserved according to a rough machining figure, and a transition slope is symmetrically machined between the cylindrical shaft part and the tabulate crank arms. With the method, internal crank arm drapes, unsuited complete fiber, local flaw detection defects and the like appearing in other bend forging methods are effectively reduced, utilization rate of steel ingots can be increased, and production cost is lowered.

Description

The forging forming method of argosy crank

Technical field

The present invention relates to a kind of crank shaping method, be specifically related to a kind of forging forming method of argosy crank, belong to forging molding technical field.

Background technology

Bent axle is one of core component of Diesel engine, be called as " heart " of engine, its manufacturing cost accounts for the 10%-20% of engine total cost, and for crank axle for vessel, this ratio even can reach 1/3, and it plays vital effect to steady, the safe operation of diesel engine.

As everyone knows, the interior tissue that crank axle for vessel is good, reasonably metal streamline and higher dimensional accuracy are inseparable with its manufacturing process.At present, in the bent axle of forging and molding, small crank can adopt solid forging method, finally obtain full-fibre crankshaft, this bent axle is mainly used in the medium and small-scale vessel being furnished with middle-size and small-size engine, and for big-and-middle-sized crank axle for vessel because the restriction being subject to instrument and supplies can only adopt the method for flat-die forging to produce, and the manufacture difficulty of big-and-middle-sized crank axle for vessel is relative to much bigger small crank.In prior art, in order to overcome the manufacture difficulty of big-and-middle-sized crank axle for vessel, usually first by crank forging molding, then by the crank after shaping and shaft member assembling and then form bent axle.

At present, the method for forging and molding of argosy crank has block to forge method, ring rolling method, die forging, upsetting method, curved forging method etc., above-mentioned method for forging and molding all has weak point in actual production, such as: block forging method, its shortcoming is that allowance is large, cost is high, and quality is difficult to up to standard, and percent defective is higher, ring rolling method, its shortcoming is that the operative skill of this technique to equipment and workman requires very high, not easily realizes aborning, and still deposits leachy danger in forging, die forging, major defect is that the crank throw of different model needs with different moulds, production cost can be relatively high, require that forcing press has very high tonnage when especially utilizing die forging to produce crankshaft used for large boat crank, in addition also have very high requirement to the intensity of mould, the application in actual production not easily realizes, upsetting method, the shortcoming of the method is that the manufacturing cost in producing is too high, is not suitable for small lot batch manufacture, curved forging method, adopt upsetting-bend-forging two one-step forming, mainly contain RR, TR, NTR, NRR method, though it is a kind of method that crank axle for vessel manufacturer of current China production crankshaft used for large boat crank generally adopts, but easily there is the serious fold of crank arm inside bottom in the method, outside convex or concave, the phenomenons such as the serious indent in crank-pin place, some indents have even exceeded machined surface, and the rear indent of processing is with local casting skin, those skilled in the art are in order to above-mentioned fold, evagination and indent are removed, then need the allowance adding big crank, reduce the utilization rate (the steel ingot utilization rate had is less than 25%) of steel ingot so undoubtedly, and then cause raw-material waste, strengthen production cost.

Summary of the invention

For above deficiency, the invention provides a kind of forging forming method of argosy crank, under the prerequisite ensureing crank crudy, improve the utilization rate of steel ingot.

Technical scheme of the present invention: the forging forming method of argosy crank, comprises the following steps:

(1) calculate steel ingot: according to roughing figure and the crank performance requirement determination forging ratio of crank, calculate steel ingot simultaneously;

(2) upsetting: steel ingot is formed " butterfly " shape crank forged piece, the above-mentioned forging ratio requirement of this crank forged piece demand fulfillment by jumping-up and pulling;

(3) roughing: rough turn processing crank forged piece, finished size meets the roughing figure of crank;

(4) curved pressure: the heating of rough machined crank forged piece will be completed, then realize pressure forming by press and mould;

(5) pressing finishing is carried out after the demoulding;

(6) heat treatment;

(7) semifinishing.

In above-mentioned steps (3), when carrying out rough turn processing crank forged piece, directly be processed into cylindric by the shaft portion in the middle of crank, the crank arm of both sides is processed into tabular and leaves allowance according to roughing figure, between cylindrical shaft part and tabular crank arm, symmetry is shaped with intermediate incline.

The present invention adopts upsetting, roughing, curved pressure three one-step forming method, its process and advantage specific as follows:

1, adopt upsetting, not only meet the forging ratio of crank request, and make crank finer and close, ensure that the Whole fiber tissue of crank throw simultaneously;

2, the present invention innovates on prior art basis increases roughing technique, namely the crank forged piece forged is processed into the shape that finished product crank opens, shaft portion in the middle of crank is directly processed into cylindric simultaneously, between cylindrical shaft part and tabular crank arm, symmetry is shaped with intermediate incline, do like this and can save a lot of surplus, greatly improve steel ingot utilization rate; In addition, owing to increasing roughing technique, therefore only the thickness of crank arm need be stayed allowance by modified amount, and fold bottom crank need not be considered and strengthen surplus especially, therefore can save raw material equally, improve and settle utilization rate;

3, the present invention be just carry out after completing roughing curved molded, as long as corresponding less pressure just directly can be pressed onto the crank forged piece after processing in bed die in this case, and by utilize the semi arch recess of upper ram and bed die circular arc pit can the direct compacting of circular shaft part of crank, crank arm is directly crowded with bed dies simultaneously, so not only maintain state after the roughing of crank shaft arm and crank axle, and due to curved molded this step do not change crank forging after Whole fiber state, a just forming step, therefore effectively prevent the phenomenons such as the inner fold of the crank arm occurred in other curved forging method and Whole fiber change and flaw detection do not conform to.

Accompanying drawing explanation

Fig. 1 is the structural representation of steel ingot.

Fig. 2 is the front view of upsetting rear crank forging.

Fig. 3 is the top view of upsetting rear crank forging.

Fig. 4 is the front view of roughing rear crank forging.

Fig. 5 is the top view of roughing rear crank forging.

Fig. 6 is the schematic diagram of crank forged piece before curved pressure.

Fig. 7 is the schematic diagram of curved pressure rear crank forging.

Fig. 8 is the schematic diagram of crank forged piece before flattening.

Fig. 9 is the schematic diagram flattening rear crank forging.

Detailed description of the invention

The forging forming method of argosy crank, comprises the following steps:

(1) steel ingot is calculated: according to roughing figure and the crank performance requirement determination forging ratio of crank, calculate steel ingot, the structure of steel ingot as shown in Figure 1 simultaneously;

(2) upsetting: steel ingot is formed " butterfly " shape crank forged piece by jumping-up and pulling, as shown in Figures 2 and 3, the above-mentioned forging ratio requirement of this crank forged piece demand fulfillment;

(3) roughing: rough turn processing crank forged piece, shaft portion in the middle of crank is directly processed into cylindric, the crank arm of both sides is processed into tabular and leaves allowance according to roughing figure, between cylindrical shaft part and tabular crank arm, symmetry is shaped with intermediate incline, finished size meets the roughing figure of crank, as shown in Figure 4 and Figure 5;

(4) curved pressure: first will complete rough machined crank forged piece 2 and heat, then crank forged piece 2 is lying on bed die 3, presses down with upper ram 1, and structure is as shown in Figure 6 and Figure 7 before the curved pressure of crank forged piece and after curved pressure;

(5) be placed on after the demoulding on lower flat anvil from bed die 3 by crank forged piece 2, clamp hyoplastron 5 with manipulator, then pass through to use upper flat anvil to carry out pressing to crank forged piece 2 and repair, crank forged piece flattens front and flattens rear structure as shown in Figure 8 and Figure 9;

(6) formation crank semifinishing product are finally heat-treated.

Claims

1. the forging forming method of argosy crank, is characterized in that comprising the following steps:

(5) pressing finishing is carried out after the demoulding;

(6) heat treatment;

(7) semifinishing.

2. the forging forming method of argosy crank as claimed in claim 1, it is characterized in that: when carrying out rough turn processing crank forged piece, shaft portion in the middle of crank is directly processed into cylindric, the crank arm of both sides is processed into tabular and leaves allowance according to roughing figure, between cylindrical shaft part and tabular crank arm, symmetry is shaped with intermediate incline.