CN1034499A - Point heating non-destructive crack arrest method and device thereof - Google Patents
Point heating non-destructive crack arrest method and device thereof Download PDFInfo
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- CN1034499A CN1034499A CN 88100160 CN88100160A CN1034499A CN 1034499 A CN1034499 A CN 1034499A CN 88100160 CN88100160 CN 88100160 CN 88100160 A CN88100160 A CN 88100160A CN 1034499 A CN1034499 A CN 1034499A
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- crackle
- metalwork
- crack arrest
- carbon electrode
- crack
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- Extrusion Moulding Of Plastics Or The Like (AREA)
Abstract
Point heating non-destructive crack arrest method and device thereof.The present invention is after finding that metalwork has crackle, uses the method without detriment to virgin metal spare, by the partial points heating, in crack tip manufacture of intraocular toughness field, this regional metal material hardness is descended, and toughness improves, to stop the crackle expansion.Can play the effect that prevents that crackle from producing equally with this method to flawless metalwork.Its device is to be made of closed DC circuit, carbon electrode, protective device.Use its effect of prestressed of the present invention to be better than extruding, roll extrusion and the stress peening process method of current use, it can be widely used in producing the production and the maintenance of the metalwork of fatigue crack, the repairing field, the aeronautical engineering maintenance and repair field that particularly requires not damage original paper is more suitable.
Description
Involved in the present invention is a kind of point heating non-destructive crack arrest method and device thereof.
Not finding this patent by retrieval, was point of application heating means of the present invention, and univ cambridge uk's material laboratory was once delivered paper in 1978, and the heating of demonstration point is to the effect of residual stress.Its method therefor is that the heating of welding gun point is different fully with this method.
There are not to find method and the device identical in the prior art with the present invention.
The purpose of this invention is to provide a kind of than more efficiently harmless crack arrest method of conventional art and device thereof.Hardware can crack under the dynamic loading and causes fracture bearing, and the method for Chu Liing was faulty part or adopted at present traditional crack arrest technology recovery in the past.These traditional crack arrest technologies all are to diminish crack arrest technology as boring stop hole, cutting, excision welding etc.The present invention can make that the part of crackle is injury-free, intensity is unaffected, the crackle propagation energy obtains stoping; The stress that it also can be applied to often crack is concentrated the position, when part is made, uses in advance, can prevent the generation of crackle, improves service life.
Feature of the present invention is with the method for electrode contact point heating, is implemented in crack tip manufacture of intraocular toughness field.Its schematic diagram is shown in figure one.Electrode (1) is made with low-resistance pure carbon rod, and circuit is the closed DC circuit of low-voltage, big electric current.In order to prevent the hot spot surface oxidation, impacted by electric arc and to prevent that heat from spreading towards periphery, realize that the temperature of (2～3 minutes) partial points can rise rapidly at short notice, use a kind of protective device (2).It is a cylindrical unit, solid a kind of powder formulation, and its composition is: carborundum, iron oxide, silica, nickel oxide and manganese dioxide.Use this device, before heated by electrodes, powder formulation surrounds electrode and hot spot surface, and at electrode and be heated between the position, installs the about 0.5 millimeter metal coating sheet (3) of a kind of thickness additional.Use said apparatus, in a heating process, can prevent that processed surface oxidation and electric arc from impacting, but the temperature of its hot spot 1300 ℃ of Gao Keda, and heating rear surface not damaged still can keep original metallic luster.Whole process only needs 2～3 minutes.Temperature measuring equipment (5) is housed on the device, and the temperature that can accurately reflect hot spot and reached is to adapt to the processing requirements of different materials.
Said method was carried out a large amount of demonstration tests, test specimen at 30CrMnSiA, 30CrMnSiNi2A, 30CrNi2MOVA, 30CrNi3A.40CrNiMOA, No. 45 materials such as steel was done the contrast fatigue test, the crackle test specimen that proof was handled through the present invention, its breaking mechanics parameter, as: fracture toughness K
1C, the most advanced and sophisticated plastic deformation merit of critical crack J
1C, threshold stress intensity factor Δ K
1N is significantly increased; Crack growth rate (da/dN) significantly descends; There is test specimen its fatigue life of the N of crackle to increase by 11～20 times.The gained result, summary is listed below:
30CrNi2MoVA：K
· 1c＝2.12K
1c
J
· 1c＝4.47J
1c
30CrMnSiA：ΔK
· th＝1.5ΔKth
30CrMnSiA：（da/dN）
＝ 1/10 （da/dN）m
30CrMnSiNi2A：ΔK
· th＝3ΔKth
30CrMnSiNi2A：（da/dN）
＝ 1/8 （da/dN）m
30CrNi2MoVA：（da/dN）
＝ 1/2.2 （da/dN）m
30CrNi2MoVA：N
＊＝14.4N
30CrMnSiA：N
＊＝20N
30CrMnSiNi2A：N
＊＝11N
Annotate: the upper right corner has
*The person is the breaking mechanics parameter after the present invention handles; Do not have
*The person is a normal condition crackle test specimen; The lower right corner has m person to be mean value.
Metallographic structure (see figure 2) to artificial plasticity field is observed, and proves that metal structure is normal, meets the requirement of toughness institutional framework, and raw material are not had influence.
Industry, widely used crack arrest process and the cracking resistance technology of diminishing in aircraft industry manufacturing and maintenance and repair field especially at present, its weak point is that the former has damage to original paper, and can not play the cracking resistance effect.The latter such as shot peening strengthening, extruding reinforcement are compared with the present invention, and it is 11～20 times that the present invention can improve fatigue fracture life-span N, and shot peening strengthening improves 5 times of life-spans; It is 3.5 times that extruding is strengthened.All do not possess as for the above-mentioned two kinds of technologies of crack arrest characteristic, they can not be applied to the part of existing crackle, and the present invention then can be used to have the crackle part to make the usefulness of crack arrest.
Equipment used in the present invention because circuit is simple, need not use vacuum tank, so equipment can make portablely, is convenient to on-the-spotly directly use.In the operating process, only need by processed the temperature that material is required, control power supply, voltage and time can realize, and these parameters can be finished by computer controlled automatic.In portable equipment, all can consider to be equipped with computer and stored program controlled, be convenient to manipulate.
Claims (5)
1, a kind of point heating non-destructive crack arrest method is characterized in that, with manual method at metalwork crack tip place or regional area make a some heat treated, manufacture of intraocular toughness field is with the cracking resistance characteristic that improves this place, stable and stop the crackle expansion.
2, the used device of a kind of point heating non-destructive crack arrest method is characterized in that, by the direct current closed path, makes the carbon electrode of some heating and the protective device of anti-oxidation and anti-thermal diffusion and constitutes.
3, by the described device of claim 2; it is characterized in that this device is with a kind of compound powder formulation; be placed in the tube; make it to surround carbon electrode and hot spot; a kind of screening glass is equipped with in the end of tube, can prevent thermal diffusion in the process of a heat treated like this; do not damage the metal surface, do not produce oxidation and electric arc and impact.
4, by claim 2,3 described devices, it is characterized in that used a kind of composite powder preparation, compound and make by carborundum, iron oxide, silica, nickel oxide and manganese dioxide.
5, by claim 2,3 described devices, it is characterized in that a kind of screening glass, is that thickness is the stalloy of 0.5 millimeter, is clipped between carbon electrode and processed, plays the effect that prevents the electric arc impact injury.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88100160 CN1013087B (en) | 1988-01-26 | 1988-01-26 | Point heating non-destructive crack-stopping method and its implement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88100160 CN1013087B (en) | 1988-01-26 | 1988-01-26 | Point heating non-destructive crack-stopping method and its implement |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1034499A true CN1034499A (en) | 1989-08-09 |
| CN1013087B CN1013087B (en) | 1991-07-10 |
Family
ID=4831203
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 88100160 Expired CN1013087B (en) | 1988-01-26 | 1988-01-26 | Point heating non-destructive crack-stopping method and its implement |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1013087B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103358086A (en) * | 2012-03-31 | 2013-10-23 | 宝山钢铁股份有限公司 | Roller surface micro-crack treatment method |
| CN104439887A (en) * | 2014-12-15 | 2015-03-25 | 大连理工大学 | Metal part internal crack repairing method |
-
1988
- 1988-01-26 CN CN 88100160 patent/CN1013087B/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103358086A (en) * | 2012-03-31 | 2013-10-23 | 宝山钢铁股份有限公司 | Roller surface micro-crack treatment method |
| CN103358086B (en) * | 2012-03-31 | 2016-12-14 | 宝山钢铁股份有限公司 | The processing method of Roller surface micro-crack |
| CN104439887A (en) * | 2014-12-15 | 2015-03-25 | 大连理工大学 | Metal part internal crack repairing method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1013087B (en) | 1991-07-10 |
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