JB/T 8822-1998 Technical requirements for high temperature centrifugal fans
Some standard content:
JB/T8822—1998
This standard is a revision of ZBJ72032--89 "Technical Conditions for High-temperature Centrifugal Fans". Compared with ZBJ72032-89, the main technical content of this standard has been changed as follows: the scope of application of the original standard has been modified;
"Terms" has been changed to "Definition"; "Maximum instantaneous temperature" has been redefined; technical requirements have been modified in 12 places (see 4.1.4, 4.1.5.4.2.1... of this standard); test methods have been modified in 6 places (see 5.1, 5.5, 5.6, 5.7, 5.8, 5.9 of this standard). Appendix A and Appendix B of this standard are both standard appendices. This standard will replace ZBJ72032-89 from the date of implementation. This standard is proposed and managed by the National Technical Committee for the Promotion of Fan Standards. The drafting unit of this standard: Siping Blower Factory. The main drafters of this standard: Qu Xiaoqiu, Liu Yifu, Liu Ye. 353
Standard of the Machinery Industry of the People's Republic of China
High temperature centrifugal fan
Technical conditions
High temperature centrifugal fan--SpecificationJB/T 8822 - 1998
Replaces ZBJ72032-89
This standard specifies the technical requirements, test methods, inspection rules, warranty period, marking, packaging and transportation of high temperature centrifugal fans. This standard is applicable to centrifugal fans (hereinafter referred to as fans) with a conveying medium temperature of more than 250℃, a dust concentration of no more than 100mg/m (standard state) and non-corrosive media. Cited standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest version of the following standards. GB/T985--1986Basic forms and dimensions of weld grooves for gas welding, manual arc welding and gas shielded weldingGB/T 986--1986
Basic forms and dimensions of weld grooves for submerged arc weldingGB/T1236--1985
GB/T 2888--1991
GB/T 8170--1987
GB/T 8923--1988
Test method for aerodynamic performance of ventilators
Numerical rounding rules for noise measurement method for fans and Roots blowers
Surface rust grade and rust removal grade of steel before paintingGB/T 13306--1991
JB/T 4730-1994
JB/T 6444--1992
JB/T 6445--1992
JB/T 6883-1993
JB/T 6887--1993
JB/T 6888--1993
JB/T 6889--1998
JB/ T 6890—1998
JB/T 9101—1999
3 Definitions
Nondestructive testing of pressure vessels
General technical conditions for fan packaging
Fan impeller overspeed test
Fan coating technical conditions
Technical conditions for iron castings for fans
Technical conditions for steel castings for fans
Fan vibration detection and its limits
Noise limits for industrial fans
Fan rotor balance
This standard adopts the following definitions.
3.1 Maximum instantaneous temperature
Refers to the short-term temperature of the system when it exceeds the maximum operating temperature under each abnormal operating condition. Each time shall not exceed 30 minutes, and the interval between each two times shall not be less than 48 hours.
4 Technical requirements
4.1 Basic design requirements
Approved by the State Bureau of Machinery Industry on September 30, 1998 354
Implemented on December 1, 1998
JB/T8822—1998
4.1.1 The fan shall comply with the requirements of this standard and shall be designed and manufactured in accordance with the drawings and technical documents approved by the prescribed procedures or in accordance with the agreement or contract requirements between the supplier and the purchaser.
4.1.2 Under the prescribed working conditions, the fan shall be designed for at least 10 years of use. 4.1.3 The critical speed of the fan main shaft (rigidity) shall be higher than 1.3 times the maximum operating speed. 4.1.4 The first overhaul period of the fan shall not be less than that specified in Table 1. Table 1
Working temperature
First overhaul period
250~450
>450～650
4.1.5 Exposed rotating parts should be equipped with removable protective devices. 4.2 Material requirements
>650～850
4.2.1 Cast iron and steel castings used in fans should comply with the provisions of JB/T6887 and JB/T6888 respectively. >850
4.2.2 The selection of impeller and main shaft materials should meet the strength and stiffness requirements, and the material properties should comply with the provisions of relevant material standards. 4.2.3 Before cutting the raw materials for rotating parts, non-destructive testing should be carried out. Only after the flaw detection is qualified and marked as required can the materials be cut. 4.2.4 The materials selected for riveted and welded parts must meet the performance requirements of the fan. 4.3 Temperature limit of fan
When the temperature is greater than 50℃, the temperature rise (temperature drop) rate of the medium transported by the fan should not exceed 50℃/h. 4.4 Riveting and welding requirements
4.4.1 The splicing of the main riveted and welded parts, the manufacturing and numbering of the sample, the blanking tolerance and the manufacturing tolerance shall comply with the provisions of Appendix B (Appendix to the standard).
4.4.2 The quality of welded parts shall comply with the provisions of Appendix A (Appendix to the standard). 4.5 Impeller requirements
4.5.1 Non-destructive testing shall be carried out after the impeller is welded. 4.5.2 Stress relief treatment shall be carried out after the impeller is welded. 4.5.3 The impeller or rotor shall be balanced and corrected, and the balance quality level shall be 5.6. 4.5.4 The overspeed test of the fan impeller shall comply with the provisions of JB/T6445. 4.6 Performance requirements
4.6.1 At rated speed, within the working area, the deviation between the measured aerodynamic performance curve of the fan and the typical performance curve shall meet the following requirements:
a) At the specified fan total pressure or static pressure, the corresponding flow deviation is ±5%; or at the specified flow, the corresponding fan total pressure or static pressure deviation is 5%;
b) The fan total pressure efficiency value shall not be lower than 5% of its corresponding point efficiency. 4.6.2 According to the different operating temperatures of the fan, corresponding cooling devices should be used in the design. Unless there are special requirements, the bearing temperature rise shall not exceed 40°C of the ambient temperature, and the maximum normal operating temperature shall not exceed 80°C. 4.6.3 The noise limit of the fan shall comply with the provisions of JB/T6890. 4.7 The painting of the fan shall comply with the relevant provisions of JB/T6883. 4.8 Completeness requirements
The scope of complete set supply of fans and the items and quantities of spare parts shall be specified by the supply and demand parties in the contract. 5 Test methods
5.1 The balance test of the impeller or rotor of the fan shall be carried out in accordance with the provisions of JB/T9101. 5.2 The no-load or load mechanical operation test of the fan shall be carried out under normal temperature conditions. The continuous operation time shall not be less than 355
20min after the bearing temperature stabilizes.
JB/T 8822-1998
5.3 If the user requires the fan to be tested at working temperature, it can be carried out on site according to the agreement between the two parties. 5.4 The aerodynamic performance test of the fan shall be carried out under normal temperature conditions in accordance with the provisions of GB/T1236 and converted into performance parameters under working conditions.
5.5 The noise measurement of the fan shall be carried out in accordance with the provisions of GB/T2888. 5.6 The vibration speed detection and its limit value of the fan shall be carried out in accordance with the provisions of JB/T6889. 5.7 The overspeed test of the impeller shall be carried out in accordance with the provisions of JB/T6445. 5.8 The ultrasonic flaw detection of materials and the non-destructive flaw detection of welds shall be carried out in accordance with the provisions of JB4730. 6 Inspection rules
Each fan must be inspected and qualified by the quality inspection department of the manufacturer and issued a certificate of conformity before it can leave the factory. 6.2 Inspection classification
The inspection of fans is divided into factory inspection and type inspection. 6.3 Factory inspection
The inspection items of fans should include:
a) Balance correction test of rotating parts;
b) Overspeed test of impeller of new product fan;c) Mechanical operation test of fan:
d) Appearance quality inspection, including inspection of assembly quality and paint quality;e) Inspection of product completeness (including the integrity of factory technical documents). 6.4 Type inspection
Type inspection items for fans should include:
a) All export inspection items;
b) Air dynamic performance test of fans;
c) Noise test of fans.
6.5 Type inspection should be carried out when fans have any of the following conditions: a) Products manufactured for the first time after identification and finalization or old products that have been transferred to production; b) After formal production, when there are major changes in structure, materials, and processes that may affect product performance; c) When the national quality supervision and inspection department proposes to carry out type inspection. 6.6 For fans of the same type and machine number produced in batches, the number of units to be tested for mechanical operation is: a) For fans with a machine number not exceeding 10, one unit should be tested for every 10 units (less than 10 units are also calculated as 10 units); b) For fans with a machine number exceeding 10, each unit should be subjected to mechanical operation test. 6.7 Acceptance of aerodynamic performance test of fans 6.7.1 For new series of fans, aerodynamic performance test must be carried out on the model and more than two typical prototypes within the circumferential speed range specified in the series, and typical performance curves including pressure, flow, power and speed shall be drawn. 6.7.2 For fans of the same series produced in batches, the number of aerodynamic performance tests to be carried out regularly is as follows: a) For fans with a machine number not exceeding 16, at least 2 prototypes shall be selected from the total number of fans of various machine numbers in the series, and the test shall be carried out at least once a year.
b) For fans with a machine number exceeding 16, the test may be carried out according to the agreement between the supply and demand parties. 7 Quality guarantee period
7.1 Under the condition that the purchaser complies with the installation and use rules of the fan, the warranty period is 8000h from the start of the use of the fan when the temperature is below 650℃; the warranty period is 5000h from the start of the use of the fan when the temperature is higher than or equal to 650℃, but it shall not exceed 18 months from the date of delivery, and the earlier expiration shall be limited. 356
JB/T 8822--1998
7.2 If the fan cannot work normally due to poor quality during the warranty period, the supplier shall repair or replace it for the purchaser free of charge. 8 Marking, packaging, transportation
8.1 Marking
8.1.1 Product labels shall be placed in obvious locations of the fan and auxiliary equipment. The contents of the label include: a) model and name;
b) main technical parameters;
c) product number;
d) manufacturing date;
e) manufacturer name and trademark.
8.1.2 The size and technical requirements of the product label shall comply with the provisions of GB/T13306. 8.2 Packaging and transportation
8.2.1 The fan shall be packaged according to the number, item and number of pieces specified in the packing list, and the packaging box shall comply with the provisions of JB/T6444. Fans are allowed to be packaged in a simple form, but the motor, instrument bearings and couplings must be waterproof, moisture-proof and vibration-proof. 8.2.2
The design of the packaging box shall comply with the regulations of the transportation department. The structure of the packaging box shall take into account the convenience of lifting, handling and long-distance transportation, multiple loading and unloading, climatic conditions, etc., and shall be suitable for water and 8.2.4
land transportation, so as not to cause product damage, quality reduction or parts loss due to poor packaging. 357
A1 Technical requirements
A1.1 Surface quality of weld
JB/T8822-1998
Appendix A
(Appendix to the standard)
Welding quality inspection of centrifugal fans
A1.1.1 The basic form and size of the weld groove shall comply with the provisions of GB/T985GB/T986 and the requirements of the drawings or process documents. A1.1.2 Weld shape:
a) The weld shape shall be uniform and smooth, and there shall be a smooth transition between welds and between welds and base metal, and there shall be no sudden changes in the cross section. b) Butt weld excess height Ah:
Lower limit: The weld shall not be lower than the surface of the steel plate, see Figure A1. Upper limit value;
Rotating parts: when 8≤3mm, Ahi≤1+0.10C, Ahz≤1+0.10C2; when 3mm, h,≤1+0.05C; Ahz≤1+0.05Cz; non-rotating parts: when ≤3mm, △h≤1+0.15Ci; △hz≤1+0.15Cz; when 8>3mm, h≤1+0.10C; 2h2≤1+0.10C2. C.
—plate thickness; C,—front weld width; C—root weld width; Ah1—front weld excess height, Ah2—root weld excess height Figure A1 Butt weld excess height
c) The actual weld leg size K of the fillet weld shall not be less than 0.9K and the weld leg thickness T shall not be less than 0.781, see Figure A2. K.
K. The size of the weld leg is specified in the drawing; K-actual size of the weld leg; 7--thickness of the weld leg; -thickness of thin plate;,thickness of thick plate Figure A2 Weld leg of fillet weld
d) The effective length of intermittent welds shall not be less than that specified in the drawing. e) Within any 25mm length range of the weld, the provisions of the surface convexity and concavity difference (6-a) are shown in Table A1 and Figure A3. 358
Fillet weld
Butt weld
JB/T8822
Weld leg size
7-lowest point of weld, 6-highest point of weld Figure A3 Concave surface of weld
f) The concave depth X at the intersection of multiple-pass and multi-layer surface overlapping welds shall not be greater than 1.5mm, see Figure A4. (Deep concave)
Figure A4 Depth of concave on weld surface
g) Within any 50mm length of weld, the difference in weld width (W1-W1) of butt weld shall not be greater than 2mm, see Figure A5. W
DSDDD2
Wideest part of weld: W2-Narrowest part of weld
Figure A5 Difference in weld width
A1.1.3 Welding defects
a) There shall be no cracks, weld penetration and unfilled pits on the weld surface. b) The undercut depth d of butt welds and fillet welds shall be specified as follows, see Figure A6. Rotating parts:
When 3≤3mm, undercut is not allowed; when>3mm, d<0.05?, and d≤0.5mm; the continuous undercut length on both sides of the weld shall not exceed 50mm, and the total length of the undercut on both sides shall not exceed 5% of the length of the weld to be inspected. Non-rotating parts:
d≤0.8mm, the length of continuous undercut on both sides of the weld shall not exceed 50mm, and the total length of undercut on both sides shall not exceed 10% of the length of the weld to be inspected (see Figure A6).
JB/T8822-1998
Figure A6 Undercut
c) Welding bead: The weld surface is not allowed to have a weld bead larger than 2mm (see Figure A7). Figure A7 Full weld bead
d) Overflow: The weld surface is not allowed to have overflow due to the molten metal pouring into the unmelted basic metal chips outside the weld (see Figure A8). Overflow
Figure A8 Overflow
e) Porosity: The weld surface is not allowed to have clustered and networked pores. Single and dense pores should meet the following requirements (see Figure A9).
-Rotating parts:
When 8≤3mm, no pores are allowed;
When 83mm, there shall be no more than 4 single pores within any 100mm long weld, and their diameter shall not be greater than 1mm, and their spacing shall be greater than 10mm.
-Non-rotating parts:
The diameter of a single pore shall not be greater than 1.5mm;
JB/T8822—1998
The diameter of dense pores shall not be greater than 0.5mm, the number shall not exceed 2, and the spacing shall be greater than 2mm. There shall be no more than 2 groups within the 1000mm long weld, and the spacing between groups shall be greater than 10mm. A1.2 Internal quality of rotating parts welding
A1.2.1 The internal quality inspection can only be carried out after the surface quality inspection of the weld is qualified. A1.2.2 There shall be no defects such as cracks, lack of fusion and lack of penetration inside the weld, as shown in Figures A10 to A12. Crack
Figure A10
Unclosed
Figure A11
A1.2.3 Circular defects in welds shall not exceed the following provisions: Unbaked
Unpenetrated
Figure A12
a) Defects with an aspect ratio of less than or equal to 3mm are defined as circular defects; b) Circular defects can be circular, elliptical, conical or with a tail (the tail should be included when measuring the size) and other irregular shapes, including pores and slag inclusions, as shown in Figure A13 and Figure A14; Porosity
Figure A13
Figure A14
c) The number and size of circular defects should not exceed the provisions of Table A2, and after evaluation, they should be selected at the location where the defects are most serious. Table A2
Thickness of parent metal.
≥10～15
>15～25
>25～50
>50～100
Assessment area size
10×10
10×10
10×20
10×30
Quality regulations for circular defects
Number of defect points
Note: The allowable number of defect points shall be converted in proportion to the corresponding base material thickness and rounded according to GB/T8170. d) When assessing circular defects, the defect size shall be converted into the number of defect points according to Table A3. Table A3 Conversion table of defect points
Defect long diameter
>1～2
>2～3
A1.2.4 Strip inclusions in welds shall not exceed the following provisions: Slag inclusions with an aspect ratio greater than 3 are defined as strip inclusions, see Figure A14. >3～4
Size of defects not counted (defect long diameter) 0.5
>4～6
>6～8
JB/T 8822·--1998
The length of a single strip inclusion and its total length shall not exceed the provisions of Table A4. Table A4 Quality provisions for strip inclusions
Thickness of parent metal?
>12～60
Inspection method
Single strip slag inclusion length
Total strip slag inclusion length
On any straight line, the distance between two adjacent groups does not exceed 6L, and the cumulative length of any group of slag inclusions within 12 weld lengths shall not exceed 8A2.1Before inspection, all scales, welding slag, spatter and other dirt that hinder inspection on the 10～20mm basic metal layer around the weld must be cleaned.
A2.2When inspecting the weld size, use the corresponding template and weld size gauge to measure. A2.3Inspection of weld surface defects
A2.3.1Surface defects that can be observed with the naked eye or a magnifying glass can be directly measured. If there is a bite edge, the size can be measured by the defect model under the putty palm.
A2.3.2Minor surface defects that cannot be seen with the naked eye or a magnifying glass shall be inspected by magnetic particle or dye flaw detection. A2.4 Inspection of internal quality of welds
If weldments need to undergo internal nondestructive testing, they must be specified in the drawings and inspected according to the flaw detection methods and flaw detection locations required by the drawings. A3 Inspection rules
A3.1After welding, weldments shall be inspected by the quality inspection department and a certificate of compliance shall be issued. A3.2All welds shall be inspected for size and surface quality, and the surface quality shall comply with the provisions of Chapter A1. A3.3Items of surface quality inspection:
a) undercut and weld bead;
b) surface pores;
c) surface cracks in weld metal and near-weld area; d) arc pits;
e) burn-through.
A3.4Defects found in the surface quality inspection may be repaired, but the number of repairs on the same weld shall not exceed 3 times. A3.5The repair welding process shall be the same as the original welding process. A3.6Nondestructive testing or internal welding quality inspection may be carried out only after the surface quality inspection is qualified. A3.7 The radiographic inspection of welds shall comply with the provisions of A1.2.2~～A1.2.4. A3.8 When ultrasonic wave is used for internal quality inspection, it shall comply with the provisions of JB4730, and the maximum allowable defect indication length shall be implemented according to Class I.
A3.9 For welds that do not meet the requirements of this standard, the defects shall be removed and re-welded, and the welds shall be inspected again after repair to meet the requirements of the standard. Welds that cannot be repaired or fail to meet the requirements of the standard after three repairs shall be scrapped. A4 Flaw detection inspection report and archiving
A4.1 After radiographic and ultrasonic inspection, the inspection results and related matters shall be recorded in detail and an inspection report shall be written. A4.2 The main contents of the flaw detection report: workpiece name, thickness, number, flaw detection method, convenient instrument, acceptance standard, flaw detection ratio, part diagram, repair situation, flaw detection conclusion, operator, person in charge and flaw detection date, etc. A4.3 The flaw detection report must be archived and properly kept for more than 3 years for inspection at any time. 362
B1 Materials for riveted and welded parts
JB/T 8822
Appendix B
(Appendix to the standard)
Technical requirements for riveted and welded parts of centrifugal fans
B1.1 The materials used for riveted and welded parts of fans shall comply with the provisions of relevant material standards, and the materials of rotating parts shall have a certificate of conformity or an inspection report. B1.2 It is strictly prohibited to use materials with defects such as interlayers and heavy skins. B1.3 The outer surface of non-rotating parts shall not have scratches with a depth of more than 0.5mm, and shall be putty-finished before painting; the outer surface of stainless steel materials shall not have scratches with a depth of more than 0.2mm. B1.4" The mechanical properties of substitute materials shall not be lower than those of the materials being replaced. B1.5 Rusty materials below Grade B in GB/T8923 shall not be used on rotating parts, nor on the outer surfaces of other parts.
B2 Splicing of main riveted and welded parts
Riveted and welded parts of fans Splicing is allowed without affecting the performance and appearance quality. The splicing of the main parts shall comply with the following provisions. B2.1 Impeller
The number of splicing blocks allowed for the impeller disc and wheel cover shall not exceed the provisions of Table B1. Except for the flat wheel cover, the other wheel covers are radially spliced. The joint positions of the impeller disc and the flat wheel cover are shown in Figure B1 and Figure B2 respectively. When the impeller is welded, the joint of the wheel cover should be opposite to the blade. Hub outer edge
Impeller diameter, mm
280-400
>400~~1 000
≥1 000~~1 600
>1 600~2 800
Joint of wheel disc
Flat wheel cover
Impeller diameter refers to the diameter of the blade outlet edge. “—” indicates that splicing is not allowed.
Number of pieces of wheel disc and wheel cover allowed to be spliced
Conical wheel cover
Single arc wheel cover
Joint of flat disc cover
Double arc wheel cover
B2. 2 Air inlet
JB/T 8822—1998
For a and b type air inlets with machine number greater than or equal to N4, an annular joint is allowed near the tangent point of the annular surface or cone surface; for c type air inlets, an elliptical joint is allowed near the tangent point; for e type air inlets, an axial joint is allowed on the cylinder plate; the joint positions of various types of air inlets are shown in Figure B3, and the number of equally divided splicing blocks is in accordance with Table B2.
Girth welding hoop
Joint positions of various types of air inlets
Machine number NO
>4～8
>8～12. 5
>12.5~~16
>16～18
>18～20
>20～22.4
>22.4～25
>25～28
B2.3 Adjustment door
Conical ring
Grooved ring
Number of equal parts of air inlet
Upper ring
Lower ring|| tt||Grooved ring
The number of allowed splicing blocks of the simple plate and flange ring of the regulating door shall be in accordance with Table B3, and the joints shall avoid equally divided holes on the circumference. B2.4 Casing
The joints of the casing side panels shall generally be parallel or perpendicular to the air outlet edge. Sugar Medical Port Continued
Conical flange
When the machine number is less than or equal to NO16, the joint position of the volute plate shall be in accordance with Figure B4: When the machine number is greater than N916, the joint position can be selected from any of Figure B4.5
>4～6
>6～8
JB/T 8822·--1998
The length of a single stripe slag inclusion and its total length shall not exceed the provisions of Table A4. Table A4 Quality provisions for stripe slag inclusions
Thickness of parent metal?
>12～60
Inspection method
Length of a single stripe slag inclusion
Total length of stripe slag inclusions
On any straight line, the distance between two adjacent groups does not exceed 6L, and the cumulative length of any group of slag inclusions within 12 weld lengths shall not exceed 8A2.1 Before inspection, all scales, welding slag, spatter and other dirt that hinder inspection on the 10～20mm basic metal layer around the weld must be cleaned.
A2.2 When inspecting the weld size, use the corresponding template and weld size gauge to measure. A2.3 Inspection of weld surface defects
A2.3.1 Surface defects that can be observed with the naked eye or a magnifying glass can be directly measured in size. If there is an undercut, the defect shape can be used under the putty palm to measure its size.
A2.3.2 Minor surface defects that cannot be seen with the naked eye or a magnifying glass can be inspected by magnetic particle or color flaw detection. A2.4 Inspection of weld internal quality
Welds that require internal non-destructive testing must be specified in the drawings and inspected according to the flaw detection methods and flaw detection locations required by the drawings. A3 Inspection rules
A3.1 After welding, the weldment shall be inspected by the quality inspection department and a certificate of compliance shall be issued. A3.2 All welds shall be inspected for size and surface quality, and the surface quality shall comply with the provisions of Chapter A1. A3.3 Items of surface quality inspection:
a) undercut and weld bead;
b) surface pores;
c) surface cracks in weld metal and near weld area; d) arc pits;
e) burn-through.
A3.4 Defects found in surface quality inspection are allowed to be repaired, but the number of repairs of the same weld shall not exceed 3 times. A3.5 The repair welding process is the same as the original welding process. A3.6 Nondestructive testing or welding internal quality inspection can only be carried out after the surface quality inspection is qualified. A3.7 The radiographic inspection of welds shall comply with the provisions of A1.2.2~～A1.2.4. A3.8 When ultrasonic wave is used for internal quality inspection, it shall comply with the provisions of JB4730, and its maximum allowable defect indication length shall be implemented according to Class I.
A3.9 For welds that do not meet the requirements of this standard, the defects shall be removed and re-welded, and the inspection shall be carried out again after repair to meet the requirements of the standard. Those that cannot be repaired or still fail to meet the standard requirements after three repairs should be scrapped. A4 NDT inspection report and archiving
A4.1 After radiographic and ultrasonic inspections, the inspection results and related matters should be recorded in detail and an inspection report should be written. A4.2 The main contents of the NDT report: workpiece name, thickness, number, NDT method, convenient instruments, acceptance criteria, NDT ratio, part diagram, repair situation, NDT conclusion, operator, person in charge and NDT date, etc. A4.3 The NDT report must be archived and properly kept for more than 3 years for review at any time. 362
B1 Materials for riveted and welded parts
JB/T 8822
Appendix B
(Appendix to the standard)
Technical requirements for riveted and welded parts of centrifugal fans
B1.1 The materials used for riveted and welded parts of fans should comply with the provisions of relevant material standards, and the materials of rotating parts must have a certificate of conformity or an inspection report. B1.2 It is strictly forbidden to use materials with defects such as interlayers and heavy skins. B1.3 The outer surface of non-rotating parts shall not have scratches deeper than 0.5mm, and shall be putty-finished before painting; the outer surface of stainless steel materials shall not have scratches deeper than 0.2mm. B1.4 The mechanical properties of the substitute material shall not be lower than those of the substituted material. B1.5 Rusty materials below grade B in GB/T8923 shall not be used on rotating parts, nor on the outer surfaces of other parts.
B2 Splicing of main riveted and welded parts
The riveted and welded parts of the fan shall be Splicing is allowed without affecting the performance and appearance quality. The splicing of the main parts shall comply with the following provisions. B2.1 Impeller
The number of splicing blocks allowed for the impeller disc and wheel cover shall not exceed the provisions of Table B1. Except for the flat wheel cover, the other wheel covers are radially spliced. The joint positions of the disc and the flat wheel cover are shown in Figure B1 and Figure B2 respectively. When the impeller is welded, the joint of the wheel cover should be opposite to the blade. Hub outer edge
Impeller diameter, mm
280-400
>400~~1 000
≥1 000~~1 600
>1 600~2 800
Joint of wheel disc
Flat wheel cover
Impeller diameter refers to the diameter of the blade outlet edge. “—” indicates that splicing is not allowed.
Number of pieces of wheel disc and wheel cover allowed to be spliced
Conical wheel cover
Single arc wheel cover
Joint of flat disc cover
Double arc wheel cover
B2. 2 Air inlet
JB/T 8822—1998
For a and b type air inlets with machine number greater than or equal to N4, an annular joint is allowed near the tangent point of the annular surface or cone surface; for c type air inlets, an elliptical joint is allowed near the tangent point; for e type air inlets, an axial joint is allowed on the cylinder plate; the joint positions of various types of air inlets are shown in Figure B3, and the number of equally divided splicing blocks is in accordance with Table B2.
Girth welding hoop
Joint positions of various types of air inlets
Machine number NO
>4～8
>8～12. 5
>12.5~~16bzxZ.net
>16～18
>18～20
>20～22.4
>22.4～25
>25～28
B2.3 Adjustment door
Conical ring
Grooved ring
Number of equal parts of air inlet
Upper ring
Lower ring|| tt||Grooved ring
The number of allowed splicing blocks of the simple plate and flange ring of the regulating door shall be in accordance with Table B3, and the joints shall avoid equally divided holes on the circumference. B2.4 Casing
The joints of the casing side panels shall generally be parallel or perpendicular to the air outlet edge. Sugar Medical Port Continued
Conical flange
When the machine number is less than or equal to NO16, the joint position of the volute plate shall be in accordance with Figure B4: When the machine number is greater than N916, the joint position can be selected from any of Figure B4.5
>4～6
>6～8
JB/T 8822·--1998
The length of a single stripe slag inclusion and its total length shall not exceed the provisions of Table A4. Table A4 Quality provisions for stripe slag inclusions
Thickness of parent metal?
>12～60
Inspection method
Length of a single stripe slag inclusion
Total length of stripe slag inclusions
On any straight line, the distance between two adjacent groups does not exceed 6L, and the cumulative length of any group of slag inclusions within 12 weld lengths shall not exceed 8A2.1 Before inspection, all scales, welding slag, spatter and other dirt that hinder inspection on the 10～20mm basic metal layer around the weld must be cleaned.
A2.2 When inspecting the weld size, use the corresponding template and weld size gauge to measure. A2.3 Inspection of weld surface defects
A2.3.1 Surface defects that can be observed with the naked eye or a magnifying glass can be directly measured in size. If there is an undercut, the defect shape can be used under the putty palm to measure its size.
A2.3.2 Minor surface defects that cannot be seen with the naked eye or a magnifying glass can be inspected by magnetic particle or color flaw detection. A2.4 Inspection of internal quality of welds
If weldments need to undergo internal non-destructive testing, it must be specified in the drawings and the inspection method and flaw detection location required by the drawings must be followed. A3 Inspection rules
A3.1 After welding, the weldment shall be inspected by the quality inspection department and a certificate of compliance shall be issued. A3.2 All welds shall be inspected for size and surface quality, and the surface quality shall comply with the provisions of Chapter A1. A3.3 Items of surface quality inspection:
a) undercut and weld bead;
b) surface pores;
c) surface cracks in weld metal and near weld area; d) arc pits;
e) burn-through.
A3.4 Defects found in surface quality inspection are allowed to be repaired, but the number of repairs of the same weld shall not exceed 3 times. A3.5 The repair welding process is the same as the original welding process. A3.6 Nondestructive testing or welding internal quality inspection can only be carried out after the surface quality inspection is qualified. A3.7 The radiographic inspection of welds shall comply with the provisions of A1.2.2~～A1.2.4. A3.8 When ultrasonic wave is used for internal quality inspection, it shall comply with the provisions of JB4730, and its maximum allowable defect indication length shall be implemented according to Level I.
A3.9 For welds that do not meet the requirements of this standard, the defects shall be removed and re-welded, and the inspection shall be carried out again after repair to meet the requirements of the standard. Those that cannot be repaired or still fail to meet the standard requirements after three repairs should be scrapped. A4 NDT inspection report and archiving
A4.1 After radiographic and ultrasonic inspections, the inspection results and related matters should be recorded in detail and an inspection report should be written. A4.2 The main contents of the NDT report: workpiece name, thickness, number, NDT method, convenient instruments, acceptance criteria, NDT ratio, part diagram, repair situation, NDT conclusion, operator, person in charge and NDT date, etc. A4.3 The NDT report must be archived and properly kept for more than 3 years for review at any time. 362
B1 Materials for riveted and welded parts
JB/T 8822
Appendix B
(Appendix to the standard)
Technical requirements for riveted and welded parts of centrifugal fans
B1.1 The materials used for riveted and welded parts of fans should comply with the provisions of relevant material standards, and the materials of rotating parts must have a certificate of conformity or an inspection report. B1.2 It is strictly forbidden to use materials with defects such as interlayers and heavy skins. B1.3 The outer surface of non-rotating parts shall not have scratches deeper than 0.5mm, and shall be putty-finished before painting; the outer surface of stainless steel materials shall not have scratches deeper than 0.2mm. B1.4 The mechanical properties of the substitute material shall not be lower than those of the substituted material. B1.5 Rusty materials below Class B in GB/T8923 shall not be used on rotating parts, nor on the outer surfaces of other parts.
B2 Splicing of main riveted and welded parts
The riveted and welded parts of the fan shall be Splicing is allowed without affecting the performance and appearance quality. The splicing of the main parts shall comply with the following provisions. B2.1 Impeller
The number of splicing blocks allowed for the impeller disc and wheel cover shall not exceed the provisions of Table B1. Except for the flat wheel cover, the other wheel covers are radially spliced. The joint positions of the impeller disc and the flat wheel cover are shown in Figure B1 and Figure B2 respectively. When the impeller is welded, the joint of the wheel cover should be opposite to the blade. Hub outer edge
Impeller diameter, mm
280-400
>400~~1 000
≥1 000~~1 600
>1 600~2 800
Joint of wheel disc
Flat wheel cover
Impeller diameter refers to the diameter of the blade outlet edge. “—” indicates that splicing is not allowed.
Number of pieces of wheel disc and wheel cover allowed to be spliced
Conical wheel cover
Single arc wheel cover
Joint of flat disc cover
Double arc wheel cover
B2. 2 Air inlet
JB/T 8822—1998
For a and b type air inlets with machine number greater than or equal to N4, an annular joint is allowed near the tangent point of the annular surface or cone surface; for c type air inlets, an elliptical joint is allowed near the tangent point; for e type air inlets, an axial joint is allowed on the cylinder plate; the joint positions of various types of air inlets are shown in Figure B3, and the number of equally divided splicing blocks is in accordance with Table B2.
Girth welding hoop
Joint positions of various types of air inlets
Machine number NO
>4～8
>8～12. 5
>12.5~~16
>16～18
>18～20
>20～22.4
>22.4～25
>25～28
B2.3 Adjustment door
Conical ring
Grooved ring
Number of equal parts of air inlet
Upper ring
Lower ring|| tt||Grooved ring
The number of allowed splicing blocks of the simple plate and flange ring of the regulating door shall be in accordance with Table B3, and the joints shall avoid equally divided holes on the circumference. B2.4 Casing
The joints of the casing side panels shall generally be parallel or perpendicular to the air outlet edge. Sugar Medical Port Continued
Conical flange
When the machine number is less than or equal to NO16, the joint position of the volute plate shall be in accordance with Figure B4: When the machine number is greater than N916, the joint position can be selected from any of Figure B4.9 For welds that do not meet the requirements of this standard, the defects should be removed and then re-welded. After repair, they should be inspected again to meet the requirements of the standard. Those that cannot be repaired or still fail to meet the requirements of the standard after three repairs should be scrapped. A4 Flaw detection inspection report and archiving
A4.1 After radiographic and ultrasonic inspections, the inspection results and related matters should be recorded in detail and an inspection report should be written. A4.2 The main contents of the flaw detection report: workpiece name, thickness, number, flaw detection method, convenient instruments, acceptance standards, flaw detection ratio, part diagram, rework situation, flaw detection conclusion, operator, person in charge and flaw detection date, etc. A4.3 The flaw detection report must be archived and properly kept for more than 3 years for inspection at any time. 362
B1 Materials for riveted and welded parts
JB/T 8822
Appendix B
(Appendix to the standard)
Technical requirements for riveted and welded parts of centrifugal fans
B1.1 The materials used for riveted and welded parts of fans shall comply with the provisions of relevant material standards, and the materials of rotating parts shall have a certificate of conformity or an inspection report. B1.2 It is strictly prohibited to use materials with defects such as interlayers and heavy skins. B1.3 The outer surface of non-rotating parts shall not have scratches with a depth of more than 0.5mm, and shall be putty-finished before painting; the outer surface of stainless steel materials shall not have scratches with a depth of more than 0.2mm. B1.4" The mechanical properties of substitute materials shall not be lower than those of the materials being replaced. B1.5 Rusty materials below Grade B in GB/T8923 shall not be used on rotating parts, nor on the outer surfaces of other parts.
B2 Splicing of main riveted and welded parts
Riveted and welded parts of fans Splicing is allowed without affecting the performance and appearance quality. The splicing of the main parts shall comply with the following provisions. B2.1 Impeller
The number of splicing blocks allowed for the impeller disc and wheel cover shall not exceed the provisions of Table B1. Except for the flat wheel cover, the other wheel covers are radially spliced. The joint positions of the disc and the flat wheel cover are shown in Figure B1 and Figure B2 respectively. When the impeller is welded, the joint of the wheel cover should be opposite to the blade. Hub outer edge
Impeller diameter, mm
280-400
>400~~1 000
≥1 000~~1 600
>1 600~2 800
Joint of wheel disc
Flat wheel cover
Impeller diameter refers to the diameter of the blade outlet edge. “—” indicates that splicing is not allowed.
Number of pieces of wheel disc and wheel cover allowed to be spliced
Conical wheel cover
Single arc wheel cover
Joint of flat disc cover
Double arc wheel cover
B2. 2 Air inlet
JB/T 8822—1998
For a and b type air inlets with machine number greater than or equal to N4, an annular joint is allowed near the tangent point of the annular surface or cone surface; for c type air inlets, an elliptical joint is allowed near the tangent point; for e type air inlets, an axial joint is allowed on the cylinder plate; the joint positions of various types of air inlets are shown in Figure B3, and the number of equally divided splicing blocks is in accordance with Table B2.
Girth welding hoop
Joint positions of various types of air inlets
Machine number NO
>4～8
>8～12. 5
>12.5~~16
>16～18
>18～20
>20～22.4
>22.4～25
>25～28
B2.3 Adjustment door
Conical ring
Grooved ring
Number of equal parts of air inlet
Upper ring
Lower ring|| tt||Grooved ring
The number of allowed splicing blocks of the simple plate and flange ring of the regulating door shall be in accordance with Table B3, and the joints shall avoid equally divided holes on the circumference. B2.4 Casing
The joints of the casing side panels shall generally be parallel or perpendicular to the air outlet edge. Sugar Medical Port Continued
Conical flange
When the machine number is less than or equal to NO16, the joint position of the volute plate shall be in accordance with Figure B4: When the machine number is greater than N916, the joint position can be selected from any of Figure B4.9 For welds that do not meet the requirements of this standard, the defects should be removed and then re-welded. After repair, they should be inspected again to meet the requirements of the standard. Those that cannot be repaired or still fail to meet the requirements of the standard after three repairs should be scrapped. A4 Flaw detection inspection report and archiving
A4.1 After radiographic and ultrasonic inspections, the inspection results and related matters should be recorded in detail and an inspection report should be written. A4.2 The main contents of the flaw detection report: workpiece name, thickness, number, flaw detection method, convenient instruments, acceptance standards, flaw detection ratio, part diagram, rework situation, flaw detection conclusion, operator, person in charge and flaw detection date, etc. A4.3 The flaw detection report must be archived and properly kept for more than 3 years for inspection at any time. 362
B1 Materials for riveted and welded parts
JB/T 8822
Appendix B
(Appendix to the standard)
Technical requirements for riveted and welded parts of centrifugal fans
B1.1 The materials used for riveted and welded parts of fans shall comply with the provisions of relevant material standards, and the materials of rotating parts shall have a certificate of conformity or an inspection report. B1.2 It is strictly prohibited to use materials with defects such as interlayers and heavy skins. B1.3 The outer surface of non-rotating parts shall not have scratches with a depth of more than 0.5mm, and shall be putty-finished before painting; the outer surface of stainless steel materials shall not have scratches with a depth of more than 0.2mm. B1.4" The mechanical properties of substitute materials shall not be lower than those of the materials being replaced. B1.5 Rusty materials below Grade B in GB/T8923 shall not be used on rotating parts, nor on the outer surfaces of other parts.
B2 Splicing of main riveted and welded parts
Riveted and welded parts of fans Splicing is allowed without affecting the performance and appearance quality. The splicing of the main parts shall comply with the following provisions. B2.1 Impeller
The number of splicing blocks allowed for the impeller disc and wheel cover shall not exceed the provisions of Table B1. Except for the flat wheel cover, the other wheel covers are radially spliced. The joint positions of the disc and the flat wheel cover are shown in Figure B1 and Figure B2 respectively. When the impeller is welded, the joint of the wheel cover should be opposite to the blade. Hub outer edge
Impeller diameter, mm
280-400
>400~~1 000
≥1 000~~1 600
>1 600~2 800
Joint of wheel disc
Flat wheel cover
Impeller diameter refers to the diameter of the blade outlet edge. “—” indicates that splicing is not allowed.
Number of pieces of wheel disc and wheel cover allowed to be spliced
Conical wheel cover
Single arc wheel cover
Joint of flat disc cover
Double arc wheel cover
B2. 2 Air inlet
JB/T 8822—1998
For a and b type air inlets with machine number greater than or equal to N4, an annular joint is allowed near the tangent point of the annular surface or cone surface; for c type air inlets, an elliptical joint is allowed near the tangent point; for e type air inlets, an axial joint is allowed on the cylinder plate; the joint positions of various types of air inlets are shown in Figure B3, and the number of equally divided splicing blocks is in accordance with Table B2.
Girth welding hoop
Joint positions of various types of air inlets
Machine number NO
>4～8
>8～12. 5
>12.5~~16
>16～18
>18～20
>20～22.4
>22.4～25
>25～28
B2.3 Adjustment door
Conical ring
Grooved ring
Number of equal parts of air inlet
Upper ring
Lower ring|| tt||Grooved ring
The number of allowed splicing blocks of the simple plate and flange ring of the regulating door shall be in accordance with Table B3, and the joints shall avoid equally divided holes on the circumference. B2.4 Casing
The joints of the casing side panels shall generally be parallel or perpendicular to the air outlet edge. Sugar Medical Port Continued
Conical flange
When the machine number is less than or equal to NO16, the joint position of the volute plate shall be in accordance with Figure B4: When the machine number is greater than N916, the joint position can be selected from any of Figure B4.
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