CN106680373A - Detection method of lamination defect of convex head of pressure container - Google Patents

Detection method of lamination defect of convex head of pressure container Download PDF

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Publication number
CN106680373A
CN106680373A CN201510753147.2A CN201510753147A CN106680373A CN 106680373 A CN106680373 A CN 106680373A CN 201510753147 A CN201510753147 A CN 201510753147A CN 106680373 A CN106680373 A CN 106680373A
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CN
China
Prior art keywords
convex head
wall thickness
detection
test block
lamination defect
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Pending
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CN201510753147.2A
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Chinese (zh)
Inventor
毛华群
王家庚
何磊
丁晓滢
胡晨
包敏
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SHANGHAI JINYI INSPECTION TECHNOLOGY Co Ltd
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SHANGHAI JINYI INSPECTION TECHNOLOGY Co Ltd
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Application filed by SHANGHAI JINYI INSPECTION TECHNOLOGY Co Ltd filed Critical SHANGHAI JINYI INSPECTION TECHNOLOGY Co Ltd
Priority to CN201510753147.2A priority Critical patent/CN106680373A/en
Publication of CN106680373A publication Critical patent/CN106680373A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/06—Visualisation of the interior, e.g. acoustic microscopy

Abstract

The invention discloses a detection method of the lamination defect of the convex head of a pressure container. The method comprises the following steps: cleaning the surface of the convex head, selecting the detection area of the convex head, and uniformly dividing the detection area into a plurality of test blocks; sequentially detecting and scanning all the test blocks by using an ultrasonic C scanning tester to obtain the weighted average wall thickness, the wall thickness standard deviation value and the wall thickness distribution percentage of every test block, and setting the range threshold FW of the wall thickness distribution of the convex head; and judging the lamination defect of the convex head according to the wall thickness percentage and a ratio of the wall thickness standard deviation value to a nominal wall thickness, and judging the position of the lamination defect in the wall thickness of the convex head according to the level of the weighted average wall thickness in the range threshold FW. The method effectively improves the detection sensitivity and the defect positioning and quantifying accuracy of the lamination defect, realizes visual and rapid determination of the lamination defect of the convex head, and meets detection demands of production fields.

Description

The detection method of pressure vessel convex head lamination defect
Technical field
The present invention relates to a kind of detection method of pressure vessel convex head lamination defect.
Background technology
Lamination defect is a kind of birth defect that steel plate is formed in the operation of rolling, and the defect is the foundation factors of the critical faults such as build-up of pressure tank plate bulge, crackle.
In Inspection of Pressure Vessel detection, coroner to the thickness measuring of the cylinder of pressure vessel and end socket can only point-to-point drafting coordinate whether there is determining lamination defect, inefficiency, the distribution situation of lamination defect and area of detection can not be quickly determined and intuitively grasp, especially for the arch section of pressure vessel convex head.Generally convex head is welded into arcwall face and is arranged at pressure container cylinder bottom using three blocks of steel plates, and the frequency of the sonigauge used during thickness measuring higher (5MHz), wavelength is shorter, sensitivity is high, as long as there is the interface of reduced size (approximately more than λ/2=0.59mm) in material, will be found by calibrator, that is the field trash interface of reduced size or little layering interfaces in steel plate mother metal, may all make calibrator shows that reading differs greatly with the actual (real) thickness of steel plate mother metal；Therefore during actual thickness measuring, run into such case, generally to use " lamination defect " place that conventional ultrasonic reflectoscope finds calibrator with normal probe to carry out scanning again in addition to make a definite diagnosis, just can be determined whether to be truly present lamination defect by waveform analyses and by experience by ultrasound detection personnel, so layered weighting of the field operation for convex head, it is not directly perceived, not quick with above-mentioned detection method, reduce detection efficiency.
The content of the invention
The technical problem to be solved is to provide a kind of detection method of pressure vessel convex head lamination defect, this method overcomes the defect of traditional convex head lamination defect detection, using Ultrasonic C-Scan detection meanss, effectively improve lamination defect detection sensitivity and defect location, quantitative accuracy, directly perceived, the quick judgement of convex head lamination defect is realized, the detection demand of production scene is met.
To solve above-mentioned technical problem, the detection method of pressure vessel convex head lamination defect of the present invention comprises the steps：
Step one, cleaning convex head surface, it is ensured that convex head surface is metal raw face or uniform skin of paint；
The maximum flanging arch section of step 2, selection convex head deflection is detection zone, and the detection zone is arranged at an endless belt outer wall below convex head weld seam radially, and this endless belt is divided into into the test block of 20 fritters；
Step 3, adopt Ultrasonic C-Scan tester with the splicing welding joint of convex head as starting point in the counterclockwise direction, slowly movement carries out successively detection scanning to each test block to hand hold transducer, and preserves the detection image of each detection block；
Step 4, the test data that each test block is obtained by Ultrasonic C-Scan tester system：
tIt is flat=(t1×S1/SAlways)+(t2×S2/SAlways)+...(tn×Sn/SAlways)
P=【(t1-tIt is flat)2×S1/SAlways+(t2-tIt is flat)2×S2/SAlways+...(tn-tIt is flat)2×Sn/SAlways】1/2
And Thickness Distribution percentage ratio BFB values,
Wherein：tIt is flatFor the weighted average wall thickness of each test block, t1、t2...tnRespectively pop one's head in the wall thickness of in each detection block each test point, S1、S2...SnRespectively pop one's head in the area of detection of in each detection block each test point, SAlwaysFor the area of each test block, P is the standard deviation value of each test block wall thickness；
Scope threshold threshold value FW of step 5, setting convex head Thickness Distribution, FW divides for third gear, respectively FW1、FW2、FW3, show layering along convex head Thickness Distribution situation,
FW1<(tg+ 2h) × 40%
(tg+ 2h) × 40%≤FW2<(tg+ 2h) × 80%
(tg+ 2h) × 40%≤FW3<(tg+ 2h) × 80%
Wherein：tgFor the nominal wall thickness of convex head, h is the weld reinforcement of convex head；
Step 6, in scope threshold threshold value FW3It is interior, as BFB ＜ 45%, show that the test block lamellar layering is serious；When 45%≤BFB≤90%, and P/tg<When 20%, show that dispersion layering occurs in the test block；When 45%≤BFB≤90%, and P/tgDuring ＞ 20%, show that lamellar layering occurs in the test block；As BFB ＞ 90%, show the test block without layering；
Step 7, judges the weighted average wall thickness t of each test blockIt is flatFall into FW1、FW2Or FW3In the range of, lamination defect is obtained positioned at the position of convex head wall thickness.
Further, the probe of the Ultrasonic C-Scan tester is the 5MHz double-crystal normal probes of diameter 10mm, and scanning precision is circumference 5mm, radial direction 1mm, and sensor sensitivity is 80%B1- 14dB, probe is using oil coupling.
Further, the ambient temperature of Ultrasonic C-Scan tester scanning convex head be 5～40 DEG C, envionmental humidity be less than 95%.
Further, the speed that the probe of Ultrasonic C-Scan tester is moved on test block is less than 150mm/s.
Because the detection method of pressure vessel convex head lamination defect of the present invention employs above-mentioned technical proposal, i.e. this method cleans first convex head surface, select the maximum flanging arch section of convex head deflection to be detection zone, and detection zone is divided into into multiple test blocks；Detection scanning is carried out successively to each test block using Ultrasonic C-Scan tester, and preserves the detection image of each detection block；Weighted average wall thickness, the standard deviation value of wall thickness and the Thickness Distribution percentage ratio of each test block are obtained by Ultrasonic C-Scan tester system, and sets scope threshold threshold value FW of convex head Thickness Distribution；Ratio with the standard deviation value of Thickness Distribution percentage ratio and wall thickness and nominal wall thickness judges the lamination defect of convex head as criterion, with certain shelves that weighted average wall thickness falls into scope threshold threshold value FW, judges that lamination defect is located at the position of convex head wall thickness.This method overcomes the defect of traditional convex head lamination defect detection, using Ultrasonic C-Scan detection meanss, lamination defect detection sensitivity and defect location, quantitative accuracy are effectively improved, directly perceived, the quick judgement of convex head lamination defect is realized, the detection demand of production scene is met.
Description of the drawings
Below in conjunction with the accompanying drawings the present invention is described in further detail with embodiment：
Fig. 1 is the construction of pressure vessel schematic diagram with convex head；
Fig. 2 is this convex head floor map.
Specific embodiment
Implement shown in such as Fig. 1 and Tu, the detection method of pressure vessel convex head lamination defect of the present invention comprises the steps：
Step one, cleaning convex head 1 surface, it is ensured that the surface of convex head 1 is metal raw face or uniform skin of paint；
The maximum flanging arch section 11 of step 2, selection convex head 1 deflection is detection zone, and the detection zone is arranged at the weld seam of convex head 1 outer wall of endless belt 13 below 12 radially, and this endless belt 13 is divided into into the test block 14 of 20 fritters；
Step 3, adopt Ultrasonic C-Scan tester with the splicing welding joint 12 of convex head 1 as starting point in the counterclockwise direction, slowly movement carries out successively detection scanning to each test block 14 to hand hold transducer, and preserves the detection image of each detection block 14；
Step 4, the test data that each test block 14 is obtained by Ultrasonic C-Scan tester system：
tIt is flat=(t1×S1/SAlways)+(t2×S2/SAlways)+...(tn×Sn/SAlways)
P=【(t1-tIt is flat)2×S1/SAlways+(t2-tIt is flat)2×S2/SAlways+...(tn-tIt is flat)2×Sn/SAlways】1/2
And Thickness Distribution percentage ratio BFB values,
Wherein：tIt is flatFor the weighted average wall thickness of each test block, t1、t2...tnRespectively pop one's head in the wall thickness of in each detection block each test point, S1、S2...SnRespectively pop one's head in the area of detection of in each detection block each test point, SAlwaysFor the area of each test block, P is the standard deviation value of each test block wall thickness；
Scope threshold threshold value FW of step 5, the setting Thickness Distribution of convex head 1, FW divides for third gear, respectively FW1、FW2、FW3, show layering along the Thickness Distribution situation of convex head 1,
FW1<(tg+ 2h) × 40%
(tg+ 2h) × 40%≤FW2<(tg+ 2h) × 80%
(tg+ 2h) × 40%≤FW3<(tg+ 2h) × 80%
Wherein：tgFor the nominal wall thickness of convex head, h is the weld reinforcement of convex head；
Step 6, in scope threshold threshold value FW3It is interior, as BFB ＜ 45%, show that the test block lamellar layering is serious；When 45%≤BFB≤90%, and P/tg<When 20%, show that dispersion layering occurs in the test block；When 45%≤BFB≤90%, and P/tgDuring ＞ 20%, show that lamellar layering occurs in the test block；As BFB ＞ 90%, show the test block without layering；
Step 7, judges the weighted average wall thickness t of each test blockIt is flatFall into FW1、FW2Or FW3In the range of, lamination defect is obtained positioned at the position of the wall thickness of convex head 1.
Preferably, the probe of the Ultrasonic C-Scan tester is the 5MHz double-crystal normal probes of diameter 10mm, and scanning precision is circumference 5mm, radial direction 1mm, and sensor sensitivity is 80%B1- 14dB, probe is using oil coupling.Wherein B1It is the first time bottom wave height in probe scanning.
Preferably, the ambient temperature of Ultrasonic C-Scan tester scanning convex head be 5～40 DEG C, envionmental humidity be less than 95%.
Preferably, the speed that the probe of Ultrasonic C-Scan tester is moved on test block is less than 150mm/s.
In inspection of one specification of Baosteel for the gas storage can container of Ф 2500 × 18 × 4500, find that the pressure vessel bottom convex head has different degrees of thinning phenomenon when coroner is with calibrator thickness measuring, corrode or be layered or nonmetal inclusion defect to distinguish difference, it is best understood from the wall thickness reduction situation of whole convex head, the convex head of the pressure vessel is detected using this method, convex head is divided and is detected using Ultrasonic C-Scan tester after detection zone.
Pluck and select the test data of the first test block as shown in table 1：
Wherein, the weld reinforcement of convex head takes 1mm, is obtained by data in table 1, in FW3In the range of, BFB values are between 45% and 90%, and P/tg＜ 20%, shows to belong to dispersion layering；Other tIt is flatFall into FW2In the range of, show that layering is occurred between the inside 8～16mm of outer wall.
The test data Macro or mass analysis for taking passages partial test block in addition are as shown in table 2：
Pluck and select the examining report page of 3# measuring points in table 2 as shown in table 3, where it is determined that procedure declaration：In the scanning scope of 3# measuring points, the data in table, according to criterion BFB (FW3)=14.09%<45%, and P/tg=27.6%>20%, serious large area lamellar layering can be exactly found quickly, lift height is largely focused in 8 millimeters of the nearly outer wall of convex head, i.e. tIt is flat=6.238 fall into FW1In the range of.
Ultrasonic C-Scan is a kind of acoustic characteristic of utilization ultrasound wave, and a series of Treatment Analysis are carried out to ultrasonic signal by computer integration system, obtains a kind of advanced detection method of Two Dimensional Acoustic image of the defect in different depth aspect.The shape of defect, position, distribution and orientation in certain depth aspect can be intuitive to see by the image for detecting.The size and distribution of defect in aspect all directions etc. can be obtained according to selected sweep parameter.Then the C-scan image in different depth aspect is overlapped using computer image processing or geometrograph, just the three-dimensional acoustics image of subject can be obtained, such that it is able to obtain stereo image, three-dimensional dimension and the spatial distribution of defect, it is suitable for detecting the corrosion default of in-service metal material and steel plate shortcoming, is such as layered, is mingled with.Thus, by Ultrasonic C-Scan detection meanss, being aided with corresponding criterion can intuitively, quickly judge the lamination defect of pressure vessel convex head to this method, improve detection efficiency and precision, meet detection demand of the production scene for convex head.

Claims (4)

1. a kind of detection method of pressure vessel convex head lamination defect, it is characterised in that this method comprises the steps：
Step one, cleaning convex head surface, it is ensured that convex head surface is metal raw face or uniform skin of paint；
The maximum flanging arch section of step 2, selection convex head deflection is detection zone, and the detection zone is arranged at an endless belt outer wall below convex head weld seam radially, and this endless belt is divided into into the test block of 20 fritters；
Step 3, adopt Ultrasonic C-Scan tester with the splicing welding joint of convex head as starting point in the counterclockwise direction, slowly movement carries out successively detection scanning to each test block to hand hold transducer, and preserves the detection image of each detection block；
Step 4, the test data that each test block is obtained by Ultrasonic C-Scan tester system：
And Thickness Distribution percentage ratio BFB values,
Wherein：For the weighted average wall thickness of each test block,Respectively pop one's head in the wall thickness of in each detection block each test point,Respectively pop one's head in the area of detection of in each detection block each test point,For the area of each test block,For the standard deviation value of each test block wall thickness；
Scope threshold threshold value FW of step 5, setting convex head Thickness Distribution, FW divides for third gear, respectively FW1、FW2、FW3, show layering along convex head Thickness Distribution situation,
Wherein：For the nominal wall thickness of convex head,For the weld reinforcement of convex head；
Step 6, in scope threshold threshold value FW3It is interior, as BFB ＜ 45%, show that the test block lamellar layering is serious；When 45%≤BFB≤90%, and P/tg<When 20%, show that dispersion layering occurs in the test block；When 45%≤BFB≤90%, and P/tgDuring ＞ 20%, show that lamellar layering occurs in the test block；As BFB ＞ 90%, show the test block without layering；
Step 7, judges the weighted average wall thickness of each test blockFall into FW1、FW2Or FW3In the range of, lamination defect is obtained positioned at the position of convex head wall thickness.
2. the detection method of pressure vessel convex head lamination defect according to claim 1, it is characterised in that：The probe of the Ultrasonic C-Scan tester is the 5MHz double-crystal normal probes of diameter 10mm, and scanning precision is circumference 5mm, radial direction 1mm, and sensor sensitivity is 80%B1- 14dB, probe is using oil coupling.
3. the detection method of pressure vessel convex head lamination defect according to claim 1, it is characterised in that：The ambient temperature of Ultrasonic C-Scan tester scanning convex head is 5～40 DEG C, envionmental humidity is less than 95%.
4. the detection method of pressure vessel convex head lamination defect according to claim 1, it is characterised in that：The speed that the probe of Ultrasonic C-Scan tester is moved on test block is less than 150mm/s.
CN201510753147.2A 2015-11-09 2015-11-09 Detection method of lamination defect of convex head of pressure container Pending CN106680373A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109596709A (en) * 2018-12-19 2019-04-09 张磊 A kind of detection method of fixed pressure vessel
CN111261305A (en) * 2019-12-30 2020-06-09 太原科技大学 Nondestructive flaw detection method for reactor pressure vessel head of offshore floating nuclear power station

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109596709A (en) * 2018-12-19 2019-04-09 张磊 A kind of detection method of fixed pressure vessel
CN109596709B (en) * 2018-12-19 2021-03-26 张磊 Detection method of fixed pressure container
CN111261305A (en) * 2019-12-30 2020-06-09 太原科技大学 Nondestructive flaw detection method for reactor pressure vessel head of offshore floating nuclear power station

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Application publication date: 20170517