JB 4744-2000 Mechanical properties test of welded test plates for steel pressure vessel products
Some standard content:
JB 4744-2000
Mechanical property inspection of welded test plates for steel pressure vessel products
UB4744—2000
Foreword
- Prepared on the basis of Appendix E of 1998, with reference to American ASMEX and drawing on years of production experience in the domestic pressure vessel manufacturing industry.
Compared with Appendix E of GB150-1998, this standard has made the following changes: 1 Scope of application
It is proposed that the inspection of the mechanical properties of the certification ring of Class B weld joints of forged welded vessels can also refer to the provisions of this standard Regulation. 2 Added reference standards
3 Product welding test plate preparation requirements and test plate preparation Added requirements and regulations for multi-layer containers and surfacing test plates. 4 Bending test
The provisions in the original standard that the diameter and bending angle of the bending shaft vary depending on the steel type, specimen type, and whether single-sided welding or double-sided welding are used. This standard adopts the regulations that the diameter of the bending axis is D=4α and the bending angle is 180°. 5 Impact test
5.1 Number of impact specimens
For the impact specimens of the weld metal, in addition to following the original standard and taking a group (3 pieces) from the last weld pass about 2mm away from the surface of the steel plate, For some special situations, a group (3) samples are added for interception. 5.2 Qualification index of impact test
Cancel the general requirement of normal temperature impact Akv ≥ 27J in the source standard, restore the requirement of impact energy based on the tensile strength of steel, and list the requirements for low temperature impact. The qualification index of austenitic steel weld metal is added, which is measured by the lateral expansion of the sample, and the expansion should be greater than 0.38mm.
6 Retest
Added the case of failure due to improper testing or non-exceeding defects, the sample is allowed to be discarded and retested. This standard will replace Appendix E in GB150-1998 from the date of implementation. This standard was proposed and promulgated by the National Pressure Vessel Standardization Technical Committee. The units responsible for drafting this standard: Hefei General Machinery Research Institute, National Pressure Vessel Standardization Technical Committee. The main drafters of this standard: Li Pingjin and Hu Jisheng. The working units and personnel participating in the preparation of this standard include: Sinopec Group Consulting Company: Yang Guoyi. China General Machinery Engineering Corporation: Qin Xiaozhong. Hefei General Machinery Research Institute: Li Jingchen. Lanzhou Petroleum Machinery Factory: Wang Zengxin.
Nanjing Chemical Industry (Group) Company Chemical Machinery Factory: Chen Shouwan. This standard is interpreted by the National Pressure Vessel Standardization Technical Committee. 69
1 Scope
Industry Standard of the People's Republic of China
Welding Test Plate for Steel Pressure Vessel Products
Mechanical property tests of product weldedtest coupons for steel pressure vesselsJB 4744—2000
1.1 This standard is applicable to the mechanical property inspection of welded test plates of various steel pressure vessel products with a design temperature not lower than -196°C. Including sample preparation, test methods, qualification indicators and retest requirements for tensile, bending and impact tests. 1.2 If the product drawings stipulate otherwise or have additional requirements, in addition to complying with this standard, they should also comply with the drawings. 1.3 The inspection of the mechanical properties of the certification ring of Class B welded joints of forged welded vessels may also refer to the provisions of this standard. 2 Referenced standards
The provisions contained in the following standards constitute provisions of this standard by being quoted in this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision and parties using this standard should explore the possibility of using the latest version of the standard listed below. GB/T2281987 Metal Tensile Test Method
GB/T229-1994 Metal Charpy Notch Impact Test Method GB/T232-1988 Metal Bending Test Method Non-destructive Testing of Pressure Vessels
JB 4730--1994F|| tt||3 symbol
L--the length of the test plate, mm;
B--the width of the test plate, mm;
d. Thickness of test plate, ms
length of sample, mm;
width of sample, mm;
6
a
hk||tt| |D-
Sample thickness, mm;
-Weld width, mm;
Bending center diameter, mm;
li clamping part length, according to the test Depends on the machine fixture, mm; - Thickness of the base layer of the composite plate, mm;
Os
Thickness of the cladding layer of the composite plate, mm;
abl
Base layer of the composite plate The lower limit of the standard tensile strength of the material, MPa; - The lower limit of the standard tensile strength of the composite panel clad material, MPa. State Machinery Industry Bureau
National Petroleum and Chemical Industry Bureau
70
2000-08-15 Approval
2000-1001 Implementation
Product Welding Test Plate Preparation requirements
JB4744-2000
4.1 Select the same steel number, same thickness, same heat treatment status, and same furnace number from the original cylinder material of the container to make a product welding test plate.
·4.2 The product welding test plate should be set at the extension of the Class A longitudinal welding joint and welded at the same time as the shell. 4.3 The product welding test plate should be marked with identification marks, including: a) work order number or container number;
b) material steel number;
c) welder steel stamp number.
4.4 For multi-layer containers, product welding test plates should be prepared separately for the inner cylinder and layers. a) The test plate of the inner cylinder and the laminate is located at the extension of the longitudinal seam of the first section of the inner cylinder and the first layer of the laminate, and is welded at the same time as the product; b) The test plate of the laminate should be made of the same material as the backing plate. The thickness should be greater than 3mm. 5 Preparation of product welding test plate specimens
5.1 Test plate size and interception of sample roughness
5.1.1 The test plate welds should be subjected to visual inspection and non-destructive testing (according to JB4730), and then Samples are taken from qualified parts. 5.1.2 The length and width of the test plate should be appropriate to meet the type and number of specimens required for the test. However, the butt joint test plate L ≥ 300 mm, B ≥ 250 mm; the surfacing test plate L ≥ 300 mm, B ~ 200 mm, (the surfacing direction is parallel to the direction of the test plate length L; when manual surfacing is used, L can be appropriately reduce). The interception of the sample is shown in Figure 1 (butt joint test plate) and Figure 2 (surfacing test plate). Abandon stretching, bending, and magic blowing,
1 butt joint test plate
Figure 1
Welding layer
Connected layer
Figure 2 Overlay welding Test plate
5.1.3 The length of the discarded parts at both ends of the test plate varies with the welding method and plate thickness. Generally, it is not less than 30mm for manual welding; it is not less than 40mm for automatic welding and electroslag welding. If there are arc-starting plates and lead-out plates, they can be discarded less or not at all. 5.1.4 Mechanical cutting is generally used to intercept the specimen hair damage. Laser or wire cutting can also be used, but the heat-affected zone should be removed. 71Www.bzxZ.net
JB4744--2000
5.1.5 When necessary, the sample can also be intercepted directly from the weldment. 5.1.6 According to the test requirements of different projects, the samples are processed. After passing the inspection, they are stamped with steel seals or other permanent marks. 5.2. Category and quantity of specimens
The category and quantity of specimens shall comply with the provisions of Table 1. Table 1 Type and quantity of specimens
Tensile
Type of specimen
Number of specimens
Note
Face bending
1
820
bent
back
curved
bent
8g>20
side bend
2
Impact
Weld metal
3 (or 6*)
Heat affected zone
3
1 when the test plate thickness When 8≤30mm, a single specimen of full plate thickness should be used; when. When >30mm, a single specimen of full plate thickness can be used, or multiple specimens can be used according to the test conditions. When using multiple specimens, all specimens covering the full thickness of the welded joint should be grouped together as one specimen. 2Test plate thickness. When it is 10~20mm, one face bend, one back bend, or two side bends can be used to replace the face bend and back bend. 3* Steel and Cr-Mo steel with the lower limit of standard tensile strength b>540MPa, and the thickness of the test plate is>60mm, and low-disposal steel with a design degree lower than -30℃ and>40mm, the number of weld metal impact specimens is 6. 4 Generally, only the impact test of the weld metal is performed, but for low-temperature equipment with a design temperature equal to or lower than -20°C, the impact test of the heat-affected zone should also be added. 6 Tensile test
6.1 The specimen dimensions of the tensile test are shown in Figure 3. Sample width 6≥25mm. R25
t
6
Figure 3 Tensile specimen
6.2 Segmentation and processing of specimen
6.2.1 Segmentation of specimen|| tt||When the tensile test of the full plate thickness cannot be carried out due to the limitation of the testing machine capacity, the test plate shall be divided into several approximately equal parts along the thickness direction, and shall be used as the specimen thickness. The thickness of the specimen shall be relatively Close to the maximum thickness that the testing machine can test. The thickness reduction caused by notch loss should be normal, that is, the thickness of several specimens superimposed after division can be less than the full thickness of the original test plate. 6.2,2 Processing of specimens
a) The reinforcement of the weld on the surface of the tensile specimen shall be removed mechanically to make it flush with the base metal. b) For materials with composite layers, when the composite layer is included in the design thickness, the tensile specimen includes the base layer and the composite layer; when the composite layer is not included in the design thickness, the tensile specimen can be prepared after removing the composite layer. c) When multiple methods are used for welding, the tensile surface of the specimen should include the weld metal of each welding method (or welding process). 6.3 Test method
The tensile test is carried out in accordance with the relevant provisions of GB/T228. After confirming that the maximum load of the tensile specimen has been read, it is allowed not to break the specimen to avoid noise and damage to the machine. 6.4 Qualification index
The tensile strength () of the tensile specimen should be greater than or equal to one of the following provisions:: 72
a) The specified value in the product drawing;
b) Steel The lower limit of the standard tensile strength;
JB4744—2000
c) For welded joints composed of steel materials of different strength levels, it is the smaller of the lower limits of the standard tensile strength of the two steel materials. or; d) If multiple pieces of divided specimens are used, the multiple pieces of specimens shall be combined into a group and each piece shall be tested. At the same time, the tensile test result of the full-thickness welded joint of the welded test plate is the average value of the group of specimens, and the average value should meet the above requirements. If broken on the base metal outside the weld or fusion line, the minimum value of this group of single-piece specimens shall not be less than 95% (carbon steel) or 97% (low alloy steel and low alloy steel) of the lower limit of the standard tensile strength of steel. High alloy steel);
e) For samples with designed thickness for cladding, it shall not be lower than the calculation result specified in the composite plate standard, that is, Gbuda + gede
+
7
Bending test
Bending specimen size
7.1
7.1.1
The dimensions of transverse face bending and back bending specimens are as shown in Figure 4 and Table 2 regulations. Table 2 Bending specimen dimensions
Thickness α
Length!
6.5α+100
Figure 4 transverse bending specimen
Width 6
38
7.1.2 The dimensions of the longitudinal bending specimen are as shown in Figure 5 and The provisions of Table 2. However, when the weld is wider, the width of the specimen can be increased accordingly. Figure 5 Longitudinal bending specimen
mm
7.1.3 The dimensions of the side bending specimen of the butt test plate are as shown in Figure 6, and the width of the specimen is the thickness of the test plate (6=). When the thickness of the test plate exceeds the width of the indenter of the testing machine (or the length of the branch), it can be cut into multiple pieces of specimens along the thickness direction that can be tested on the testing machine, and a side bending test is performed on each piece of specimen. The dimensions of the side bend specimen of the surfacing test plate shall be as specified in Figure 7. The width of the specimen 6 for assessing the fusion condition of the surfacing transition layer may be 38 mm. Center
1.50
Figure 6 side bending sample
0
73
7.2 Sample processing
JB4744—2000||tt ||200
Figure 7 Side bend specimen of surfacing test plate
The weld reinforcement or backing plate on the bent specimen should be removed mechanically, and the tensile surface of the specimen should be flush. The edges and corners of the sample should be rounded, and the radius of the fillet should not be greater than 2 mm. When it is 10-20mm and face-bent and back-bent specimens are used, the thickness of the specimen is the thickness of the test plate, that is, αs.
7.3 Test method
7.3.1 Bending test According to the relevant provisions of GB/T232, the weld and heat-affected zone of the specimen should be included in the bending deformation range, and the bending axis of the specimen should be bent transversely. The center should be aligned with the center of the weld. 7.3.2 When the base metal on both sides of the welded joint or the base metal and the deposited metal have a large difference in strength or a significantly different elongation, longitudinal bending specimens can be used for testing.
7.3.3 For joint bending test of composite steel plate and corrosion-resistant surfacing, take 2 side bend specimens for testing. 7.4 Qualification indicators
7.4.1 After the sample is bent to the specified angle according to the requirements of Table 3, there shall be no single crack or defect with a length greater than 3mm in any direction on the tensile surface. Cracks at the edges and corners of the specimen are not counted, but the length of cracks at the edges and corners of the specimen caused by slag inclusions or other welding defects is accrued.
When using multiple pieces of specimens, form a group of multiple pieces of specimens and conduct a test on each specimen, which shall meet the requirements of this article. 7.4.2 For the weld bead and fusion line of the corrosion-resistant surfacing layer, the surfacing layer shall not have any cracks or defects larger than 1.5 mm; the fusion line shall not have any cracks or defects larger than 3 mm. Table 3 Bend test parameters
Sample thickness, mm
a
8 Impact test
8.1 Form and size of impact specimen
Bending center diameter D, mm
4a
The form and size of the impact specimen are in accordance with the provisions of GB/T229. 8.2 The sample interception and the azimuth support distance of the sample notch, mm2
6a+3
bending angle α, (\)
180
8.2.1 Impact test specimens should be taken perpendicular to the welding direction, and the axis of the specimen notch should be perpendicular to the surface of the test plate. The notch of the impact specimen of the weld metal is located in the center of the weld.
8.2.2 For composite panels, unless the drawings and users have special requirements, generally only impact samples of the base layer are taken. 8.2.3 When the lower limit of the standard tensile strength of steel αb ≤ 540MPa, take a set of impact specimens of the weld metal on the weld side of the last weld pass, with a distance of 12mm from the steel plate surface as the upper surface of the impact specimen (Figure 8 group I). 8.2.4 The lower limit of the standard tensile strength of steel ob>540MPa and Cr-Mo steel, and the thickness of the test plate. >60mm, and for low-temperature steel with design temperature lower than -30℃ and ≥40mm, take two sets of impact test specimens of weld metal. One group is located on the last weld bead side 1 to 2mm away from the surface of the steel plate; one group is between the surface of the other side of the steel plate and 1/2 the plate thickness (that is, the 1/4 plate thickness on the other side is the longitudinal axis of the impact sample ) interception (two groups I and II in Figure 8).
74
t/sg
JB4744—2000
Figure 8 Intersection of weld metal impact specimen
8.2.5 Impact test in heat affected zone The location of such a gap is shown in Figure 9. The distance (S) from the notch axis to the intersection of the specimen axis and the fusion line is greater than zero, and should pass through as much of the heat affected zone as possible. 8.3 Test method
Perform normal temperature or low temperature impact according to the drawing requirements. The test method is in accordance with the relevant provisions of GB/T229. If the low temperature impact is qualified, normal temperature impact can be avoided.
Weld metal
Heat affected zone
Figure 9 Interception of impact sample in heat affected zone
8.4 Qualification index
8.4.1 Normal temperature impact energy The specified value is specified in the drawing or relevant technical documents, but the average impact energy of the three specimens shall not be less than 27J (for the 10 mm×10 mm×55 mm specimen) or 14J (for the 5 mm×10 mm×55 mm specimen) ). 8.4.2 Low-temperature impact: At the specified test temperature, for carbon steel and low alloy steel, it is determined according to the lower limit of the tensile strength of the steel; for austenitic stainless steel, it is measured according to the lateral expansion of the sample. All should comply with the requirements of Table 4. Table 4 Low-temperature Charpy (V-notch) impact test minimum impact energy and lateral expansion steel tensile strength lower limit value products
MPa
450
>450～515| |tt||>515～650
Austenitic steel weld metal
Average AkV of impact energy of 3 samples, J
10 mm × 10 mm ×55 mm
18
20
27
10 mm×5 mm×55 mm
9
10
14| |tt||Lateral expansion of the sample
mm
0.38
The average impact energy of the three samples at the test temperature shall not be less than the specified value in Table 4, where The impact energy of one sample may be less than the specified value, but shall not be less than 70% of the specified value.
9 re-inspection
9.1. If the tensile and bending test of the welded product test plate fails, retesting is allowed. For unqualified items, take double samples for re-inspection (if the face bending fails, take 2 more samples for face bending), and the qualification indicators should meet the requirements of 6.4 and 7.4 respectively. 9.2 If the impact test results cannot meet the requirements of 8.4, retesting is allowed. For unqualified items (such as welds or heat-affected zones; Group I or Group II), take another set of (3) samples for testing. The qualification index is: the average impact energy of the two groups of 6 samples before and after shall not be 75
JB47442000
lower than the specified value. Two samples are allowed to be smaller than the specified value, but one of them is smaller than the specified value 70 Only 1% is allowed. 9.3 If the reason for failure in a certain test is due to poor test conditions or improper operation, the test will be invalid and retest is allowed.
9.4 If the impact energy on the fracture surface of the impact sample is unqualified due to defects permitted by non-destructive testing (not exceeding the standard), the sample will be discarded and retested.
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