CN103600035A

CN103600035A - Manufacturing technology of walking machinery bracket casting

Info

Publication number: CN103600035A
Application number: CN201310070070.XA
Authority: CN
Inventors: 马建华; 张龙楼; 范小亮
Original assignee: Nantong Huadong Hydraulic Technology Co Ltd
Current assignee: Nantong Huadong Hydraulic Technology Co Ltd
Priority date: 2013-03-06
Filing date: 2013-03-06
Publication date: 2014-02-26

Abstract

The invention discloses a manufacturing technology of a waking machinery bracket casting. The technology comprises the following steps: step a, manufacturing a shell mould of a precoated sand box and an upper mould; step b, arranging an exothermic riser in the center position of the upper mould; step c, pouring molten iron into the precoated sand box within 8 to 10 seconds at a temperature of 1380 DEG C; step d, placing an exothermic agent on the top part of the exothermic riser after the pouring process, allowing the box to stand still, wherein in this process, the exothermic property of the exothermic riser is utilized so as to prolong the solidification time of the molten iron, the feeding is strengthened, the stand-still time is 1 to 1.5 hours, and the molten iron cools and forms a casting blank; step e, subjecting the casting blank to a post-treatment so as to obtain a finished casting. The manufacturing technology has the advantages that: through the experiments of the technology mentioned above, casting dissection and dye penetrant inspection both meet the clients' requirements, the technology yield is raised from 33% to 71%, and thus the casting production cost is largely reduced.

Description

A kind of manufacturing process of walking machine bracket foundry goods

Technical field

The present invention relates to a kind of manufacturing process of walking machine bracket foundry goods, specifically the bracket foundry goods that hydraulic system is used is controlled in a kind of automation.

Background technology

What the present invention relates to is 6324120-0203 bracket foundry goods.Be extensive use in the heavy walking machine manufactures such as Kawasaki, Japan company 31 heavy industrys, be mainly used in the running gear of the engineering machinery such as excavator, bull-dozer, it is stressed larger.This product is as the stressed part of key of walking machine, and all higher to its mechanical property, fatigue behaviour, interior tissue and compactness requirement thereof, foundry goods must carry out defect detecting test.

One, the important technological parameters of bracket

1, important technological parameters

Casting weight 17KG

Product material: QT600-3

Tensile strength: >=600MPa

Percentage elongation: >=3%

Hardness: 192-241HB

Graphite form: spherical, nodularization rate >=85%

Foundry goods must not have shrinkage cavity and porosity

At present this product manufacture is mainly overseas business, and this manufacturing technology is secrecy technology, rarely has report at home and abroad on document.

When the preparation technology of this valve body of research, to find, this technique has following difficult point to be difficult to capture:

(1) foundry goods thermal center disperses, and needs the position of molten iron feeding many, how to guarantee that foundry goods does not have the defect of slag inclusion, shrinkage cavity and porosity;

(2) under the prerequisite that guarantees the internal quality of casting, carry out process modification, improve the product yield of foundry goods, reduce the production cost of foundry goods.

In order to solve above-mentioned technology contents, also done the research of following scheme:

Two, critical process implementation process

1, the top of four pillars of cast top adopts four sand rising heads (A, B, C, D) and four exothermic risers (E, F, G, H) to test respectively, its result two schemes all below four foundry goods pillars also lower plane junction (diagram a place) there is shrinkage cavity, analyze its reason because pillar is higher and larger with junction, bottom (a place) thermal center, riser feeding distance and Feeding channel are not smooth, cause junction to occur shrinkage cavity defect.

2, adopt side riser technique: longer for riser feeding distance, technique is improved.Continue to adopt four rising heads (E, F, G, H) to carry out feeding to four thermal centers, rising head is changed to middle part, four pillar sides of foundry goods, rising head just approaches foundry goods thermal center place like this, is conducive to the feeding of foundry goods.Through overtesting, dissect dye penetrant inspection, foundry goods is not found shrinkage cavity or shrinkage defect.But we have found problem when calculating product yield, and the product yield of foundry goods is too low, only has 33%.So low product yield causes the production cost of foundry goods very high, has wasted a lot of molten iron, has affected production efficiency.

Summary of the invention

Main task of the present invention is to provide a kind of manufacturing process of walking machine bracket foundry goods, the manufacturing process of the walking machine bracket foundry goods that specifically a kind of molten iron feeding is effective, casting quality is good and casting process yield is high, castings production cost is low.

In order to solve above technical problem, the manufacturing process of a kind of walking machine bracket foundry goods of the present invention, is characterized in that: a, making overlay film sandbox outer casing mold, patrix: the imitative type structure using the polycrystalline substance of foundry goods as upper mold cavity; Counterdie: the imitative type structure using the superstructure of foundry goods as lower mold cavity;

B, at the centre bit of patrix, install exothermic riser;

C, by molten iron at the temperature of 1380 ℃, at 8-10, in second, be poured in overlay film sandbox;

D, standing after exothermic mixture is put at rising head top after pouring, utilizes the heat generation characteristic of rising head, the setting time that extends molten iron, strengthening feeding; Time of repose is 1-1.5 hour, cooling formation spray;

E, post processing obtain finished product cast.

Further, described molten iron order number is 150-300;

Further, the diameter of described exothermic riser is 90mm.

Advantage of the present invention:

By the test of above technological measure, foundry goods is dissected and dye penetrant inspection reaches customer requirement, and product yield is increased to 71% by original 33%, greatly reduces the production cost of foundry goods.

Accompanying drawing explanation

Fig. 1 is the structural representation that the top of four pillars of background technology cast top adopts four sand rising heads and four exothermic risers.

Fig. 2 is the schematic diagram that four dead heads of background technology are poured into a mould from the side.

Fig. 3 is bed die top view in the present invention.

Fig. 4 is middle mould top view in the present invention.

Fig. 5 is cover mold top view in the present invention.

Fig. 6 is overlay film sandbox outer casing mold top view in the present invention.

Fig. 7 is along A-A line cutaway view in Fig. 4.

Fig. 8 is along B-B line cutaway view in Fig. 4.

Fig. 9 is the rising head front view in the present invention.

Figure 10 is the rising head top view in the present invention.

Figure 11 is dye penetrant inspection schematic diagram of the present invention.

The specific embodiment

The present embodiment is disclosed is 6324120-0203 bracket foundry goods.

As shown in Fig. 1, Fig. 3 to Figure 10: concrete technology is as follows:

A, making overlay film sandbox outer casing mold, comprise bed die 1, cover mold 3 and middle mould 2, and described bed die 1, middle mould 2 and cover mold 3 stack gradually setting from bottom to top, between bed die 1, cover mold 3 and middle mould 2, by cylindric positioning convex, position,

B, at the centre bit of patrix 1, install 90mm exothermic riser 5; Described rising head 5 radially cuts 1/3 from middle and upper part for traditional rising head, forms upper and lower two joints (5a, 5b), die joint place horizontal one screen pack 4 between two joints, and form the rising head with filtering function with bonding upper and lower two joints (5a, 5b) of binding agent.It should be noted that; Cast gate, rising head unification in the present embodiment.As shown in Figure 5.

E, conventional post processing obtain finished product cast.

(1) advantage of the foundry goods making by this technique and particular manufacturing craft: molten iron system of risers: changing original four thermal center places is to adopt an exothermic riser teeming to concentrate feeding with four side riser feeding technologies.

(2) molten iron filtration system: directly pour into a mould a difficult problem for pushing off the slag for solving molten iron from rising head, we have taked filter-type exothermic riser, and molten iron just can filter by screen pack like this.

(3) by after above two innovations, reduced rising head usage quantity, and directly poured into a mould and saved sprue, cross gate from rising head, made the product yield of foundry goods bring up to 71% by 33 original %.

Figure is for completely qualified, specifically as shown in figure 11 in foundry goods section dye penetrant inspection.

Claims

1. a manufacturing process for walking machine bracket foundry goods, is characterized in that: step is as follows:

A, making overlay film sandbox outer casing mold, patrix: the imitative type structure using the polycrystalline substance of foundry goods as upper mold cavity; Counterdie: the imitative type structure using the superstructure of foundry goods as lower mold cavity;

B, at the centre bit of patrix, install exothermic riser;

E, post processing obtain finished product cast.

2. the manufacturing process of a kind of walking machine bracket foundry goods according to claim 1, is characterized in that: described molten iron order number is 150-300.

3. the manufacturing process of a kind of walking machine bracket foundry goods according to claim 1, is characterized in that: the diameter of described exothermic riser is 90mm.