This standard specifies the side groove test method for determining the fatigue crack growth rate of welded joints. JB/T 6044-1992 Side groove test method for fatigue crack growth rate of welded joints JB/T6044-1992 Standard download and decompression password: www.bzxz.net

Machinery Industry Standard of the People's Republic of China
Fatigue crack growth rate of welded joints
Side machine test method
1 Subject inner sleeve and applicable scope
This standard specifies the determination of welding Side groove test method for fatigue crack growth rate of joints JB/T 6044-92
This standard is suitable for measuring metal material fusion welding joints (base metal, weld seam) in room humidity (15~35℃) and atmospheric environments The fatigue crack growth rate of the side sugar sample under a constant amplitude cyclic load (gold chips and heat shadow area) is greater than 10-5mm/cycle. This method may also be used for the stress crack growth rate test of sugar samples on the joint side in non-room temperature and non-atmospheric environments. 2 Referenced standards
GB9447 Welded joint fatigue crack growth rate test method 3 terms and codes
3. 1 Side groove
Sandalwood opened along the crack expansion direction of the specimen, the side groove is divided into Through trough and semi-through trough. 3.2 Through-groove
The side groove that runs through the entire geometric centerline of the specimen. Because it constrains crack propagation in two directions, it can also be called a two-dimensional sugar. 3.3 Semi-through groove
Side groove that is not through. Because it restricts crack growth in three directions, it can also be called a three-dimensional groove. 3.4 Sugar grows W.
The groove length starting from the center line of the force application point and along the crack propagation direction. For through-slot specimens, the slot length is W. It should be equal to the width W of the specimen. 3.5 Groove width E
The notch width of the specimen surface in the axial direction of the vertical side groove. 3.6 Groove depth H.
The measurement from the surface of the sample to the bottom of the side sugar trough.
3. 7 side sugar radian R,
radius of the round bottle at the root of the side groove of the sample.
4 Test pieces and specimens
4.1 Preparation of test pieces
4.1.1 When used in the selection of welding materials and the evaluation of welding processes, the original conditions for specimen preparation must be Comparability. 4.1.2 When used to estimate the life of a welded structure, the test piece must be intercepted from the real component. If it is necessary to replace it with a welded test piece, the materials, welding process conditions, and rolling direction conditions of the test piece and the component should be kept consistent. 4.2 Sample
4.2.1 Crack growth rate da/dN standard CT (close reading tensile) side groove sample is shown in Figure 1. It is used to determine the crack growth rate of weld metal. The Ministry of Mechanical and Electronics Industry of the People's Republic of China approved 290 on May 05, 1992
Implemented on July 01, 1993
JB/T 6044-92||tt| | A kind of through-groove sample; if the dα/dNV of the heat-affected zone or other parts of the joint is measured, the measuring grid of the sample should be opened at the corresponding part to be measured. Its life
10.002W4
-+0. 25W+8. 05
Jo. 002w
coan
6
B| |tt||a±0.005W
w±o.o1w(ww.)
1. 25W±0. 01W
d
or||tt| |H.
Note: Other areas of the welding head replacement can be used for reference. 000 thousand
ms2
00 292
[6. 002w
[ o. 002w
DD
@
@
[ 0.002wA
Figure 1da/dN standard cT side groove sample diagram
{S0'0T 49 0150 0 in 49 %
4.2.2 adopt other type of specimen [such as the specimen A1 in Appendix A (reference part)], there must be a suitable opening method and corresponding stress intensity factor calibration.
291
4.3 Sample size
JB/T 6044-92
4.3.1 Other sample sizes except side grooves shall be in accordance with GB9447. 4.3.2 The geometric dimensions of the side groove refer to the length, groove width, groove depth and side groove angle, which are essentially determined by the K factor calibration, see Article 7.2.2. Appendix A gives the specific dimensions of a sample for reference. 4.4 Preparation of the side groove of the specimen
4.4.1 Use metallographic corrosion agent to corrode the weld bead to be tested so that the outline of the weld bead is clearly displayed. 4.4.2 It should be ensured that the groove root trace is a straight line located in the measured part of the welded joint (center of the weld, fusion zone, heat affected zone, etc.). 4.4.3 Any appropriate mechanical processing method can be used, but the accuracy and surface roughness of the side grooves must be ensured. It is required that the machining cut marks must be perpendicular to the crack expansion line.
4.4.4 In order to ensure the roughness of the groove itself, it is recommended to use the tool for grinding side grooves in Appendix B (inspection parts). 4.5 Residual stress of the specimen
4.5.1 The design and processing of the specimen should minimize the influence of residual stress. The influence of residual stress in welded structures is considered in defect tolerance analysis and life estimation.
4.5.2 In order to reduce the influence of residual stress, samples with a small thickness-to-width ratio (B/W) can be selected. 5 Fatigue testing machine and fixture
5.1 Fatigue testing machine
5.1.1 The test is allowed to be carried out on different types of testing machines, but it is ensured that the line connecting the upper and lower loading points of the test is perpendicular to the sugar root trace. 5.1.2 When correcting the load under static conditions, the error shall not exceed ±1%, and the fluctuation of the indication value shall not exceed ±1%; when correcting the load under dynamic load, the error shall not exceed ±3%.
5.1.3 Equipped with an accurate counting device, a timer can be added to the counter to correct the counter. If the counter needs to be amplified, attention should be paid to the error (the error value depends on the design requirements).
5.2 Clamp
CT specimen loading device
The U-shaped clamp can be designed with reference to Figure 2. The yield strength of the clamp material should be greater than 2 times the maximum service strength of the specimen material. The gap between the pin and the pin hole should be designed to minimize friction, and the loading pin should be coated with lubricant. The proportions and tolerances of the U-shaped clamp and the pin shaft should comply with the requirements in Figure 2. 6 Test procedures
6.1 Preparation before the test
6.1.1 Sample measurement
Before the test, apply a measuring tool with an accuracy of 0.01mm to the flat plate part and the groove root part of the sample three times each. Measure the thickness B and B value of the sample at each position and take the average value.
Use a measuring tool with an accuracy of not less than 0.001W to measure the width of the side groove of the sample. Use a measuring tool with an accuracy of 0.01mm to measure the groove depth H at three positions at the center of the side groove and take the average value. 6.1.2 The cuts and side grooves should be cleaned before testing. 6.2 Prefabricated fatigue crack and fatigue crack growth rate test 6.2.1 Prefabricated fatigue crack
The length, applied load and testing machine frequency of the prefabricated fatigue crack shall comply with the regulations of GB9447. 6.2.2 Fatigue crack growth rate test||tt ||The measurement requirements for fatigue crack length, length measurement accuracy, crack measurement spacing, and test interruption requirements should all comply with GB9447.
6.2.3 Number of specimens
Usually each group should ensure that there are two specimens with the same crack growth area. 292
7 Processing of test results
0.4
C
?
0
7.1 Fracture inspection and crack curvature correction|| tt||JB/T 6044—92
M0.35W
2E
0.05
1
L0. 05 [AD
ms
?
s
ZH MS& 0T
A—D
0.051C
(a) U-shaped clamp||tt ||2×45*
228
AS
(b) Pin shaft
o.1w
Figure 2 U-shaped pin hole of CT sample Fixture
7. 1.1 After the test, conduct a metallographic inspection and record the area where the crack surface is located. 0. 4W
.1W
fo. 25W-8:11
7.1.2 During the fracture observation, if macroscopically visible pores, slag inclusions, lack of fusion, and lack of welding are found When there are welding defects such as penetration and cracks, the test data on the crack growth rate around the defects are invalid. 7.1.3 If curvature correction must be used, the regulations of GB9447 should be followed. 7.2 Calculation of stress intensity factor range AK
7.2.1 Standard flat plate CT specimen
AK-
AP(2+α)
X(0.886+4.64α —13.322+14.72—5.6a)BW(1-α)3/2
q≥0.2 The above relationship is valid
where: α=a/W;
++ +++-..
.(1)
293
W—sample width.mm
B-sample thickness,mm
AP-Pmx -Pmin .
7.2 .2 Standard side groove CT specimen Www.bzxZ.net
JB/T 6044-92
Calibrated using the da/dN relationship of the flat plate standard CT specimen: (da/dN)→-m (da/dN) ·
Where: m, β-
test constant;
(2)
m, β are the comparative results of the crack growth rate test between flat plate and side groove Intercept and slope on log-log scale. Or there should be appropriate AK factor calibration (such as Appendix A). The relationship between AK in da/dN is calculated using the commonly used paris formula L (3): da/dN-c(AK)*
where;,n\—
test constant.
7.3 Data validity test
Standard side-mounted CT sample requirements:
W--a≥4/r(Kmx/oo.2)
7.4 data The processing procedure
can be stipulated in GB9447 if it meets the accuracy requirements. 8 Test report
The test report shall include the following contents:
(3)
(4)
8.1 The orientation of the sample taken from the welded joint, the direction of the side groove position. If the welded joint is taken out of the welded structure, its position in the structure and a sampling diagram must be given.
8.2 The general mechanical properties of the deposited metal and base metal, the heat treatment specifications and welding parameters of components and test pieces should be given. 8.3 Geometric parameters of the specimen. Draw detailed drawings of the position of the weld bead in the test piece, including the width, thickness and macro shape of the weld bead. 8.4 Testing machine model, crack length measurement device and accuracy, loading variables, including load range AP, load ratio R, loading frequency and waveform. 8.5 Environmental impact parameters, including temperature, environmental medium, relative humidity, and the maximum deviation of each parameter during the entire test period. 8.6 Data processing methods, including whether the curvature of fatigue cracks is corrected, determining da/dN and AK, as well as the relationship between da/dN and AK and the calculation program used. When the load ratio is less than zero, the method for calculating the minimum stress intensity factor Kmin should be stated. 8.7 AK factor calibration results of standard CT side slot specimens, or da/dN relationship calibration results of flat plate standard CT specimens. 8.8 The test results should be tabulated. When the (da/dN)-△K curve data points are given on logarithmic coordinate paper, in order to better compare the data, the abscissa (logK) size can be 2 of the ordinate [log (da/dN) size ~3 times. 8.9 Any phenomena causing abnormal data must be explained. 294
A1 Meal test sample 1
JB/T 6044—92
Appendix A
Reference sample
(reference part)||tt| |The stress intensity factor calibration of reference sample 1 is according to formula (A1), and the sample size is shown in Figure A1. cAPva
AK-
NBB.W
where: test constant c=38;
geometric parameter B-10; Bn=B—2H.=6.3; W-2-12 °4
TFO
0
Meal test sample?
A2
W2
Talk
Arr
W.-77
W-95
12||tt ||6
H
E
Reference sample 1
Figure Al
The stress intensity factor calibration of reference sample 2 is according to the formula (A2) , sample dimensions are shown in Figure A2. AK-
△P(2+α)
Qile3.2
EE
X(0.886+4.64a—13.32a+14.72a3-5.6)B, vW(1-α)a2
Where: α=u/W;
B, 6.3.
(A1)
(A2)
★
295
296
2--2 +No. 05||tt| |Aoia
[o.1Aa]
JB/T6044—92
920008
r
W-50
62.5 ±0.5
maa
5a
Figure A2 Reference sample 2
Standard CT side groove sample picture
The rest
o.
3.2
6.3
e
1
HO
Note: The medium size matches the side sugar shun degree.
Additional instructions:
JB/T6044—92
Appendix B
Side groove machining abrasive form
(reference part)
Figure B1
Schematic diagram of side groove machining abrasives
This standard is proposed and managed by the Harbin Welding Research Institute of the Ministry of Machinery and Electronics Industry. This standard is drafted by Harbin Welding Research Institute. The main drafters of this standard are Zhang Baochang and Jiao Wei. 297
-77
W-95
12
6
H
E
Reference sample 1
Figure Al
The stress intensity factor calibration of reference sample 2 is according to formula (A2). The sample size is shown in Figure A2. AK-
△P(2+α)
Qile3.2
EE
X(0.886+4.64a—13.32a+14.72a3-5.6)B, vW(1-α)a2
Where: α=u/W;
B, 6.3.
(A1)
(A2)
★
295
296
2--2 +No. 05||tt| |Aoia
[o.1Aa]
JB/T6044—92
920008
r
W-50
62.5 ±0.5
maa
5a
Figure A2 Reference sample 2
Standard CT side groove sample picture
The rest
o.
3.2
6.3
e
1
HO
Note: The medium size matches the side sugar shun degree.
Additional instructions:
JB/T6044—92
Appendix B
Side groove machining abrasive form
(reference part)
Figure B1
Schematic diagram of side groove machining abrasives
This standard is proposed and managed by the Harbin Welding Research Institute of the Ministry of Machinery and Electronics Industry. This standard is drafted by Harbin Welding Research Institute. The main drafters of this standard are Zhang Baochang and Jiao Wei. 297
-77
W-95
12
6
H
E
Reference sample 1
Figure Al
The stress intensity factor calibration of reference sample 2 is according to formula (A2). The sample size is shown in Figure A2. AK-
△P(2+α)
Qile3.2
EE
X(0.886+4.64a—13.32a+14.72a3-5.6)B, vW(1-α)a2
Where: α=u/W;
B, 6.3.
(A1)
(A2)
★
295
296
2--2 +No. 05||tt| |Aoia
[o.1Aa]
JB/T6044—92
920008
r
W-50
62.5 ±0.5
maa
5a
Figure A2 Reference sample 2
Standard CT side groove sample picture
The rest
o.
3.2
6.3
e
1
HO
Note: The medium size matches the side sugar shun degree.
Additional instructions:
JB/T6044—92
Appendix B
Side groove machining abrasive form
(reference part)
Figure B1
Schematic diagram of side groove machining abrasives
This standard is proposed and managed by the Harbin Welding Research Institute of the Ministry of Machinery and Electronics Industry. This standard is drafted by Harbin Welding Research Institute. The main drafters of this standard are Zhang Baochang and Jiao Wei. 297
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