CN102936647A - Method for prolonging fatigue life of welded joint subjected to mechanical surface strengthening - Google Patents
Method for prolonging fatigue life of welded joint subjected to mechanical surface strengthening Download PDFInfo
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- CN102936647A CN102936647A CN201210459908XA CN201210459908A CN102936647A CN 102936647 A CN102936647 A CN 102936647A CN 201210459908X A CN201210459908X A CN 201210459908XA CN 201210459908 A CN201210459908 A CN 201210459908A CN 102936647 A CN102936647 A CN 102936647A
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Abstract
The invention discloses a method for prolonging the fatigue life of a welded joint subjected to mechanical surface strengthening. By means of an ultrasonic impact process, a weld toe position of the welded joint is subjected to certain fatigue cycles and then subjected to once impacting so that small cracks which are produced by previous processing in a certain limit and slowly extend can be effectively eliminated, and the impacted surface returns to the state after the previous impacting. Appropriate fatigue cycles are spaced so that left fatigue life of the welded joint which is subjected to ultrasonic impacting and strengthening can be effectively prolonged. According to the method, an ultrasonic impacting device is economical, light and simple in operating, and the method is high in feasibility and obvious in effects. According to the experimental verification, by means of the method, the fatigue life of the welded joint subjected to mechanical strengthening can be effectively prolonged by about 1.5 times.
Description
Technical field
The invention belongs to the solder joint fatigue technical field, more particularly, relate to the method for a kind of raising through welding joint fatigue lifetime of surperficial mechanical enhancer, specifically for what processed by ultrasonic impact, and for some time but do not reach the design welding joint of fatigue lifetime of being on active service, can effectively extend its residual life under cyclic loading.
Background technology
Fatigue refers to the performance variation that material occurs under Cyclic Load.Fatigure failure is the one of the main reasons of engineering structure and mechanical failure, causes that the peak value of cyclic loading of fatigue failure is often much smaller than " safety " load estimated according to static fracture analysis.
From welded application, people just notice that weldment is the same with other hardwares, should focus on the fatigue design of welding assembly.Yet welding joint has again its singularity, generally, welded construction has globality and its rigidity is increased, and stress is difficult in uniform state, easily produce larger stress concentration, and concentrated scope is wider.Easily produce fatigue cracking at stress raiser (fault location often), if crackle continues expansion in the structure use procedure, just may cause structural damage to be lost efficacy under certain condition.Ultrasonic impact is processed in 1972 by Russian scientist Statnikov invention, for ship and submarine member, to strengthen fatigue property and corrosion resistance.Can be used for the processing to multiple differing materials such as carbon steel, stainless steel, aluminium, titaniums.Its strengthening mechanism is as follows:
1. produce controlled residual compressive stress layer in material;
2. crystal grain thinning, form considerable strengthening layer in treat surface;
3. controllably change the local geometric shape of welding toe, improve stress concentration.
Quantity research shows greatly, and ultrasonic impact is processed the fatigue property to material, no matter in high week or low cycle fatigue, all has a very significant increase, and can arrive the several times of through ultrasonic impact, not processing member fatigue lifetime.
Summary of the invention
The object of the invention is to overcome the deficiencies in the prior art, in order to improve on the basis of fatigue lifetime in the mechanical intensive treatment in surface, welded construction is further improved fatigue lifetime, the method of a kind of raising through welding joint fatigue lifetime of surperficial mechanical enhancer is provided, the method is on the basis of original strengthening, make fatigue lifetime that further lifting be arranged again, and simple to operate, feasibility good, Considerable effect.
Technical purpose of the present invention is achieved by following technical proposals:
The present invention considers that welding joint is after ultrasonic impact is processed, and significantly increase its fatigue lifetime, observes fatigue fracture and finds that crackle is to be parallel to surperficial wire expansion, is different from the point-like formation of crack annular expansion of as-welded fracture.This is because ultrasonic impact while processing, though produced residual compressive stress, refinement surface microstructure, improved stress concentration processing position, has inevitably introduced microlesion, and this become the crackle crack initiation source of impacting the state fracture.
A kind of method improved through welding joint fatigue lifetime of surperficial mechanical enhancer of the present invention, initially after the ultrasonic impact strengthening and experiencing one section fatigue loading, the Welded Joints welding toe carries out the method for ultrasonic impact processing again, can effectively eliminate the fine crack that produces and slowly expand by front primary treatment under certain limit, surface after making to impact is returned to the state after front one-shot, can realize and so forth effectively extending the purpose of the remanent fatigue life of the welding joint of strengthening through ultrasonic impact.
Raising adopts after one section fatigue loading of welding joint experience again to the processing method that Shih-chao's acoustic shock is processed in fact through the method for the welding joint residual life of ultrasonic impact strengthening, makes to impact rear surface and returns to state after front one-shot, and concrete steps are as follows:
1. the sample after at first ultrasonic impact being processed carries out the cycle cyclic loading to fracture, and, according to the fatigue lifetime under test result calculations 95% survival probability 75% degree of confidence, is denoted as N
T
2. then the sample after the initial ultrasound shock treatment is carried out stopping loading after the cycle cyclic loading of certain hour, after re-starting ultrasonic impact and processing, then carry out the cycle cyclic loading
At sample after identical circulation cycle fatigue loading, again stop loading, after the Welded Joints place carries out the ultrasonic impact processing, then carry out the cycle cyclic loading, until fracture
Described ultrasonic impact is processed and is concentrated on welding soldering tip position, especially welding toe, and excusing from death shock treatment parameter is exciting current 1.0A, amplitude 26.4 μ m, and striker pin should be perpendicular to the toe of weld center, and does (10-20 °) side throw by a small margin; In loading procedure, while carrying out ultrasonic impact, need to concentrate on welding soldering tip position, especially welding toe, near 10mm zone toe of weld is covered fully, fraction of coverage reaches 300%(to each point of application ultrasonic impact 3 times), excusing from death shock treatment parameter is exciting current 1.0A, amplitude 26.4 μ m, and striker pin should be perpendicular to the toe of weld center, and do (10-20 °) side throw by a small margin, need upper one ultrasonic impact vestige covered fully.
The time of described cycle cyclic loading is (to be denoted as N the fatigue lifetime under 95% survival probability 75% degree of confidence recorded in step 1
T) 50% or 75%.
The present invention adopts ultrasonic impact technique Welded Joints welding toe after certain tired cycle again to impact, can effectively eliminate the fine crack that is produced and slowly expanded by front primary treatment under certain limit, the surface after making to impact is returned to the state after front one-shot.The tired cycle that interval is suitable, can effectively extend the remanent fatigue life through the welding joint of ultrasonic impact strengthening.The ultrasonic impact equipment economy the present invention relates to, light, simple to operate.Method feasibility provided by the invention is strong, and effect is remarkable, in actual application, can select equipment downtime to check period, does again ultrasonic impact and processes.Through verification experimental verification, adopt method provided by the invention, effectively improve through approximately 1.5 times of mechanical enhancer welding joint fatigue lifetives.
The accompanying drawing explanation
In Fig. 1 embodiment of the present invention, fatigue sample machining shape figure, wherein be of a size of a=300mm; B=75mm; C=25mm; D=52mm; Arc radius e=150mm; F=50mm; G=12mm; H=12mm; Roughness i=1.6; Roughness j=1.6
First group of fatigue test results in Fig. 2 embodiment of the present invention
Second group of fatigue test results in Fig. 3 embodiment of the present invention
The 3rd group of fatigue test results in Fig. 4 embodiment of the present invention
Embodiment
Below in conjunction with specific embodiment, further technical scheme of the present invention is elaborated
The equipment that embodiment is related: the Dimension 372 type welding machines of the HJ-III type ultrasonic impact machine that the permanent development in science and technology of Tianjin Tian Dong company limited produces, the GPS300 type HF fatigue testing machine that Changchun Academy of Machinery Science & Technology Co., Ltd. manufactures, the production of Miller company.The material related to has: S690 low-alloy high-strength steel, the FabCO XTREME of HOBART company 120 type flux-cored wires.
60 ° of " X " type grooves of the thick S690 sheet material processing of 12mm, joint form is the carrying cruciform joint, adopts carbon dioxide-shielded welding to carry out multi-pass welding, welding condition are as shown in table 1.Then be processed into the fatigue test test specimen according to Fig. 1, divide three groups and carry out fatigue test, stress ratio R=0.5, stress range Δ σ=200MPa.
First group: the Welded Joints welding toe carries out the ultrasonic impact processing, and processing parameter is exciting current 1.0A, amplitude 26.4 μ m, then carry out fatigue test to fracture, (be denoted as N the fatigue lifetime that can calculate under 95% survival probability 75% degree of confidence
T)
Second group: the Welded Joints welding toe carries out the ultrasonic impact processing, same first group of parameter, then carry out fatigue test, load cycle 0.75N
TStop when inferior loading, carry out ultrasonic impact for the second time and process, then continue to load 0.75N
TThe inferior the third challenge that carries out, so repeatedly to fracture, the parameter that for the second time described and later excusing from death shock treatment adopts with ultrasonic impact is identical for the first time, ultrasonic impact is processed and near 10mm zone toe of weld need be covered fully, fraction of coverage reaches 300%(to each point of application ultrasonic impact 3 times), striker pin should be perpendicular to the toe of weld center, and does 15 ° of side throws by a small margin, when ultrasonic impact is processed again, need upper one ultrasonic impact vestige covered fully
The 3rd group: implementation process is similar to second group, and each cycle index shortens to 0.5N
T.
Table 1 welding condition
The fatigue results data are carried out Treatment Analysis according to " given applied stress lower fatigue lifetime statistical estimate " part in standard GB/T 24176-2009 " metallic substance fatigue data statistical project and analytical procedure ".The result obtained as shown in Figure 2,3, 4.And can calculate every group of fatigue test results, the fatigue lifetime under 95% survival life-span 75% degree of confidence.It is 97498 times that the first batch total is calculated result; The second batch total is calculated result: 234501 times; It is 245539 times that the 3rd batch total is calculated result.Second group of result of all processing apparently higher than first group of single ultrasonic impact with the 3rd group of result.
Above the present invention has been done to exemplary description; should be noted that; in the situation that do not break away from core of the present invention, the replacement that is equal to that any simple distortion, modification or other those skilled in the art can not spend creative work all falls into protection scope of the present invention.
Claims (5)
1. a raising is through the method for welding joint fatigue lifetime of surperficial mechanical enhancer, it is characterized in that, initially after the ultrasonic impact strengthening and experiencing one section fatigue loading, the Welded Joints welding toe carries out the ultrasonic impact processing again, to eliminate the fine crack that produces and slowly expand by front primary treatment, surface after making to impact is returned to the state after front one-shot, and then loaded, can realize and so forth effectively extending the purpose of the remanent fatigue life of the welding joint of strengthening through ultrasonic impact.
2. a kind of method improved through welding joint fatigue lifetime of surperficial mechanical enhancer according to claim 1, it is characterized in that, after one section fatigue loading of welding joint experience, again Shih-chao's acoustic shock is in fact processed, make to impact rear surface and return to state after front one-shot, and then carry out fatigue loading, concrete steps are as follows:
(1) at first the sample after the ultrasonic impact processing is carried out to the cycle cyclic loading to fracture, and, according to the fatigue lifetime under test result calculations 95% survival probability 75% degree of confidence, be denoted as N
T
(2) then the sample after the initial ultrasound shock treatment is carried out stopping loading after the cycle cyclic loading of certain hour, after re-starting ultrasonic impact and processing, then carry out the cycle cyclic loading
(3) at sample after identical circulation cycle fatigue loading, again stop loading, after the Welded Joints place carries out the ultrasonic impact processing, then carry out the cycle cyclic loading, so repeatedly, until fracture.
3. a kind of method improved through welding joint fatigue lifetime of surperficial mechanical enhancer according to claim 2, it is characterized in that, described initial ultrasound shock treatment concentrates on welding soldering tip position, especially welding toe, excusing from death shock treatment parameter is exciting current 1.0A, amplitude 26.4 μ m, striker pin should be perpendicular to the toe of weld center, and does 10-20 ° of side throw by a small margin; In loading procedure, while carrying out ultrasonic impact, need to concentrate on welding soldering tip position, especially welding toe, near 10mm zone toe of weld is covered fully, fraction of coverage reaches 300%, excusing from death shock treatment parameter is exciting current 1.0A, amplitude 26.4 μ m, and striker pin should be perpendicular to the toe of weld center, and do (10-20 °) side throw by a small margin, need upper one ultrasonic impact vestige covered fully.
4. a kind of method improved through welding joint fatigue lifetime of surperficial mechanical enhancer according to claim 2, is characterized in that, the time of described cycle cyclic loading is (to be denoted as N the fatigue lifetime under 95% survival probability 75% degree of confidence recorded in step 1
T) 50% or 75%.
5. method as described as one of claim 1-4 is in the application of welding joint in fatigue lifetime that improves the S690 low-alloy high-strength steel.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104975250A (en) * | 2015-06-29 | 2015-10-14 | 柳州金茂机械有限公司 | Surface treatment technology of titanium alloy bucket welded joint |
| CN104975162A (en) * | 2015-06-29 | 2015-10-14 | 柳州金茂机械有限公司 | Surface treatment technology of bucket welded joint |
| CN105643186A (en) * | 2016-03-28 | 2016-06-08 | 华东交通大学 | Cyclical ultrasonic impact process for maintaining welding joint |
| CN105953960A (en) * | 2016-04-19 | 2016-09-21 | 苟国庆 | Database establishing method and database use method of database for evaluating train body safety |
| CN107460302A (en) * | 2017-08-08 | 2017-12-12 | 合肥正明机械有限公司 | A kind of processing method for improving weldment fatigue life |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004131744A (en) * | 2002-10-08 | 2004-04-30 | Nippon Steel Corp | Method for improving fatigue strength of lap welded joint |
| JP2008000802A (en) * | 2006-06-23 | 2008-01-10 | Nippon Steel Corp | Method for improving fatigue strength of lap welded metal joint |
| JP2008274415A (en) * | 2007-03-30 | 2008-11-13 | Nippon Steel Corp | Long rail and manufacturing method therefor |
| CN102002581A (en) * | 2010-12-17 | 2011-04-06 | 南车长江车辆有限公司 | Method for eliminating residual stress in welding by ultrasonic peening and use thereof |
-
2012
- 2012-11-14 CN CN201210459908XA patent/CN102936647A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004131744A (en) * | 2002-10-08 | 2004-04-30 | Nippon Steel Corp | Method for improving fatigue strength of lap welded joint |
| JP2008000802A (en) * | 2006-06-23 | 2008-01-10 | Nippon Steel Corp | Method for improving fatigue strength of lap welded metal joint |
| JP2008274415A (en) * | 2007-03-30 | 2008-11-13 | Nippon Steel Corp | Long rail and manufacturing method therefor |
| CN102002581A (en) * | 2010-12-17 | 2011-04-06 | 南车长江车辆有限公司 | Method for eliminating residual stress in welding by ultrasonic peening and use thereof |
Non-Patent Citations (2)
| Title |
|---|
| 《天津大学学报》 20090630 尹丹青等 "Q235钢和16Mn钢接头超长寿命疲劳行为及疲劳寿命设计" 第513-517页 1-5 第42卷, 第6期 * |
| 尹丹青等: ""Q235钢和16Mn钢接头超长寿命疲劳行为及疲劳寿命设计"", 《天津大学学报》 * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104975250A (en) * | 2015-06-29 | 2015-10-14 | 柳州金茂机械有限公司 | Surface treatment technology of titanium alloy bucket welded joint |
| CN104975162A (en) * | 2015-06-29 | 2015-10-14 | 柳州金茂机械有限公司 | Surface treatment technology of bucket welded joint |
| CN105643186A (en) * | 2016-03-28 | 2016-06-08 | 华东交通大学 | Cyclical ultrasonic impact process for maintaining welding joint |
| CN105953960A (en) * | 2016-04-19 | 2016-09-21 | 苟国庆 | Database establishing method and database use method of database for evaluating train body safety |
| CN105953960B (en) * | 2016-04-19 | 2018-07-06 | 西南交通大学 | A kind of foundation of database for being used to evaluate train body safety and application method |
| CN107460302A (en) * | 2017-08-08 | 2017-12-12 | 合肥正明机械有限公司 | A kind of processing method for improving weldment fatigue life |
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Application publication date: 20130220 |