JB/T 6889-1993 Technical requirements for defect repair of cast iron parts for fans
Some standard content:
Machinery Industry Standard of the People's Republic of China
Technical Conditions for Repair of Defects in Cast Iron Parts for Fans 1 Subject Content and Scope of Application
This standard specifies the technical requirements for repair of defects in cast iron parts for fans, quality inspection and acceptance. JB/T6889--93
This standard applies to gray cast iron, ductile iron, medium manganese anti-wear ductile iron, high silicon corrosion-resistant cast iron, heat-resistant cast iron and other castings (hereinafter referred to as castings) used in various types of fans. Repair of casting defects caused and discovered during casting and processing. Unless there are special provisions in drawings, technical documents or ordering agreements, the repair of casting defects shall comply with the provisions of this standard. Defective castings are castings that do not meet the acceptance conditions (including machined or unmachined surfaces). The purpose of repairing defects is to achieve the appearance quality and intrinsic quality specified in the acceptance conditions. Normal grinding should not be regarded as repairing defects. When the defects of a casting fall within the scope of repair allowed by this standard, the casting is regarded as a repaired or repaired part and is included in the work-in-progress quantity. Small defects on the surface of the casting that do not reduce the structural strength and do not affect the appearance quality do not need to be repaired. Surface defects within the machining allowance range are allowed on the machined surface of castings
2 Reference standards
JB/T6887 Technical conditions for cast iron parts for fans 3 Technical requirements
3.1 Parts that are not allowed to be repaired or parts and defects a
b.
c.
d.
f.
blades on reflow chambers, diffusers, blisks ; Shaft holes of hubs, pulleys, couplings, etc.; Roots blower impeller surface (except end face), fan hub surface: processing parts with a surface roughness R value of 1.6 or less, as well as metal-to-metal friction work Defects in the lifting lugs of casings, transmissions, etc., or other parts prone to safety accidents: Defects in thin oil storage and pressure-bearing castings that are sufficient to cause leakage (threaded plugs can be used for local leakage parts) Plugging); any crack-like defects on castings that are subject to impact loads and bear large bending moments and torques. g.
3.2 Defects that do not need to be repaired
Cracks and cold shuts in castings are not allowed to exist. Other defects such as tiny pores, blisters, slag inclusions, shrinkage cavities and shrinkage porosity do not need to be repaired. Specifically According to the following regulations:
3.2.1 Any minor defects that do not exceed the range specified in Table 1 do not need to be repaired. 3.2.2 The area of ??each dense pore shall not exceed 300mm2, and its location and scope are shown in Table 1. 3.2.3 For stationary castings, which do not store thin oil and non-pressure-bearing parts, the depth of shrinkage defects shall not be greater than 6mm and shall not be greater than the wall where it is located. Half of the thickness, the defect area shall not be greater than 15% of the shrinkage area (hot section), but the maximum shall not be greater than $25mm. 3.2.4 Rotating parts such as hubs, pulleys, half couplings, etc. are not allowed to have any defects on the surface of the shaft hole after processing, within the radius length from both ends; the rest of the inner surface of the shaft hole is The defect is allowed to exist when the depth of the defect is not greater than 3mm, the diameter is not greater than 1/5 of the shaft diameter, and the circumferential length between two defects is not greater than the shaft diameter. 3.3 Defect repair methods and quality requirements
The Ministry of Machinery Industry of the People's Republic of China approved 232 on 1993-07-13
Implemented on 1994-07-01
3.3.1 Plugging||tt| |Casting types
Parts
Parts
Hole name
Non-machined surface
Hole
Stationary parts
Moving parts
plus
table
work
will
hole
limit
eye
‖ density Pore
surface
hole
non-machined surface
plus
work
hole
Back
Eye
Service
Dense poresWww.bzxZ.net
Face
JB/T 6889-93
Table 1 Defects that do not need to be repaired Range
Aperture size
6
5
2.
5
4
2
Hole depth
3
2
1.5
3
2
1
Hole spacing
20
25
10/41
25
30
10/31
away from the edge
edge The distance of
8
10
8
8
10
8
Note: 1) The molecule indicates the length The numerator represents the number of small pores. 10/3 means no more than 3 small pores per 10mm length. mm
number of holes per 100cm2 surface
number of holes (pieces)
6
6
2 places
5
5
2 places
3.3.1.1 For defects such as pores, blisters, and slag inclusions on castings that store thin oil and pressure-bearing parts, cast iron (or chromium steel) threaded plugs that are the same as the base material can be used Stuffed. The plug diameter shall not be greater than the wall thickness. 3.3.1.2 For stationary parts weighing more than 1000kg, hole defects on the machined surface can be filled with cast iron (or chromium steel) inlays (plugs or inserts) alternate with the base material. The size of the embedded figure should not be larger than 1/5 of the size of the blockage, the depth of the embedded figure should be 20~45mm (not more than 1/2 of the wall thickness of the blockage), and the distance from the edge of the embedded figure to the edge of the surface should not be less than 30mm. Each process surface Do not fill more than 2 places. Cylindrical plugs only fit, and the inserts should meet the
fit of the shadow. | |tt | Defects such as pores, blisters, slag inclusions, shrinkage cavities, shrinkage porosity, cracks, cold shuts, and missing meat can be repaired by welding in accordance with the following regulations as long as they do not affect the performance, service life, and appearance quality of the casting: a. Defects within the scope of repair shall be inspected and approved before repair welding can be carried out. Before welding, the defects need to be cleaned up, the metal base material is exposed and the groove is shoveled out, and then welding is carried out according to the welding repair process. Welding is not allowed under the cold draft of b.
. During cold welding, each weld is generally 20~~30mm. After welding, the welding repair area should be lightly hammered. The hammering time is equivalent to the welding repair time. Hammer while welding until the weld is full. However, the first and last layers should not be hammered. When using multi-layer welding, in order to avoid overheating of the welding repair area, try to use small-diameter electrodes and perform intermittent welding repairs with low current. For each welding pass, the slag from the previous pass should be removed. If there are defects of different sizes on the cast iron at the same time, they can be repaired by welding alternately, or in order from small to large. The welding rod must be dried according to the instruction manual. The drying temperature of cast iron welding rod is generally 100~200C and the constant temperature time is 1 hour. After welding repairs, stress relief annealing should generally be performed; for defects that occur during machining, when the welding repair area is small and the welding stress is not large, annealing is not required after welding. c. For defects on the machined surface, the cast iron hot welding method should be used to repair. Before welding, the cast iron should be partially or completely preheated (450~~550C) and then gas welded or electric welded. Immediately after welding, it should be covered with insulation material (such as straw ash, or charcoal chips); for small local defects after finishing, iron or nickel-copper cast iron welding rods can be used for cold welding; for hole defects on the non-machined surface, nickel-free cast iron welding rods can be used for cold welding or semi-heat welding Weld to repair.
When cracks or cold insulation occur in the ribs and non-oil-storing, non-pressure-bearing parts of the casting, when the length of the defect is not more than 3 times the wall thickness, it can be repaired by welding.
Repair before welding Drill $4-~8mm anti-crack holes at the end. e. For parts that do not store oil and are not pressure-bearing parts, if a single through hole appears and the hole diameter is less than 1.5 times the wall thickness (maximum not exceeding $35mm), it can be repaired by welding.
f For defects such as pores, blisters, slag inclusions, shrinkage cavities, and shrinkage porosity that appear on castings, the size and quantity of welding repairs shall not be greater than those specified in Table 2: the depth of defects shall not be greater than that for stationary parts. 2/3 of the wall thickness. For moving parts, it shall not be greater than 1/3 of the wall thickness; the distance between two defects shall not be less than 2.5 times the largest defect size.
233
Stationary parts
Moving parts
g.
Casting classification
Weight, kg
Defect size Φ ,mm
JB/T 6889—93
Table 2 Allowable range of welding repair for burr ring casting defects Small parts
100
40
each The number of surface defects is not more than,
defect size$,,mm |
50
2
Large
piece
Extra large piece
≥400～1 ??600
>1 600~ 6 300
80
70
100
90
Defects such as pores, blisters, slag inclusions, and shrinkage holes that appear in castings during machining If the repair performance does not affect the service performance and processing performance, and meets the following requirements, it is allowed to be used after welding repair: the size and quantity of the defective welding repair shall not be greater than the provisions of Table 3; the depth of the defect shall not be greater than 1/3 of the wall thickness for stationary parts. 2. For moving parts, it shall not be greater than 1/4 of the wall thickness; the distance between two defects shall not be less than 2.5 times the maximum defect size. Table 3 The scope of welding repair allowed for defects occurring in mechanical processing Casting classification
Weight, kg|| tt||Static parts
Moving parts
3. 3.2. 2
(Defect size Φ+mm
The number of defects on each surface is not more than,|| tt||Defect size $, mm
The number of defects on each surface should not be more than, pieces
Small pieces
100
30
2| |tt||20
pieces
>100~~400
50
40
big
pieces
400~1 600
70
3
60
2
Extra large items
>1 600-~6 300||tt ||85
70
If the casting defects exceed the relevant provisions of Clause 3.3.2.1, but the production unit has higher skills and reliable welding repair quality measures, it must be agreed by the design department or the purchaser. Only then can welding repairs be carried out, and necessary non-destructive testing and leakage test inspections must be carried out. 3.3.2.3 Welding repair quality requirements
a.
The weld metal should be well fused with the base metal, and the weld should be well fused. Smooth, without pores, slag inclusions and cracks; b.
The color of the processed weld is the same as or similar to the base material; for defects on the exposed processing surface, the welding zone (including welding seam, fusion zone and heat The hardness of the affected area) shall not be higher than HB255, and shall not affect the machinability;
For defects on castings that require leakage testing, after welding repair, they should comply with the requirements of JB6887 "Technical Conditions for Cast Iron Parts for Fans" d. | |tt | For defects such as shrinkage holes, slag holes and hole diameter deviations, the round holes of the castings can be appropriately enlarged according to this standard and then inserted into the castings without affecting the quality of the parts and the performance of the fan. 3.3.3.2 Technical requirements for key sets
a.
b.
心.
d.
e.
234| | tt | |tt||The sleeve should be fixed to the casting with seam screws. When the sleeve is subjected to axial force, it should be equipped with a sleeve with a boss; it is not allowed to be embedded with an eccentric sleeve, nor is it processed into an eccentric sleeve after the sleeve is inserted; two sleeves are not allowed to be embedded in the same hole.
Inner diameter of insert
80
>80～150
>150~～200
>200～500
JB/T 6889--93
Table 4
3.3.3.3 Important parts such as the main shaft hole, the oil tank and hydraulic parts hole, and the bearing cover hole must not be nested. 3.3.4 Fill
minimum wall thickness of the sleeve
10
15
mm
small defects (pores, pores, Blisters, slag inclusions, etc.) can be filled with epoxy resin special filler or putty without affecting the rigidity and appearance quality of the casting. Small defects on process-processed surfaces, cover-processed surfaces, and unimportant fixed joint surfaces without precision requirements that are not suitable for welding repair or plugging can also be filled with special epoxy resin fillers of similar colors and adhesive fixation (castings) The working temperature should generally not exceed 90℃)
Before filling, the defective parts should be mechanically treated by filing, scraping, sandblasting or cleaning with gasoline, acrylic copper and other solvents according to relevant regulations. If the casting requires stress relief annealing, it should be filled after annealing. 4 Inspection of welding repair quality
4.1 The cleaning of defective welding repair areas should be inspected one by one, and should be carried out in accordance with the requirements of 3.3.2.1b and 3.3.2.1d. 4.2 The welding repair method and welding rod used shall be in accordance with the relevant provisions of Article 3.3.2.1b and Article 3.3.2.1c. 4.3 After defective welding is repaired, the quality of each welding area should be inspected one by one to meet the requirements of Article 3.3.2.3. Check the hardness with a hammer or Shore hardness tester.
4.4 The number, size, area, etc. of defects in welding repairs shall not exceed the provisions of this standard. 4.5 Any crack-type defects on castings that are subject to large bending moments and torques under impact loads should be inspected using effective methods after welding repairs. 5 Acceptance
After the casting defects are repaired, they shall comply with the repair quality requirements in this standard or the ordering agreement, and shall be inspected and accepted in accordance with the regulations on casting quality in JB6887 "Technical Conditions for Castings for Fans". Additional notes:
This standard is proposed and managed by the National Technical Committee for Fan Standardization. This standard is drafted by Shaanxi Blower Factory; Shanghai Blower Factory, Wuhan Blower Factory, Shenyang Blower Factory, Shenyang Foundry, and Chongqing General Machinery Factory participated in the drafting
The main drafters: Wang Kuiwang, Song Lili, and Chaoyen Chaoren. 235
1. In individual cases, if defects such as pores, shrinkage holes, slag holes and hole diameter deviations are found in the machined surface of unimportant round holes in castings, the round holes of castings can be processed according to this standard without affecting the quality of the parts and the performance of the fans. After proper expansion, it is inlaid with human slips. 3.3.3.2 Technical requirements for key sets
a.
b.
心.
d.
e.
234| | tt | |tt||The sleeve should be fixed to the casting with seam screws. When the sleeve is subjected to axial force, it should be equipped with a sleeve with a boss; it is not allowed to be embedded with an eccentric sleeve, nor is it processed into an eccentric sleeve after the sleeve is inserted; two sleeves are not allowed to be embedded in the same hole.
Inner diameter of insert
80
>80～150
>150~～200
>200～500
JB/T 6889--93
Table 4
3.3.3.3 Important parts such as the main shaft hole, the oil tank and hydraulic parts hole, and the bearing cover hole must not be nested. 3.3.4 Fill
minimum wall thickness of the sleeve
10
15
mm
small defects (pores, pores, Blisters, slag inclusions, etc.) can be filled with epoxy resin special filler or putty without affecting the rigidity and appearance quality of the casting. Small defects on process-processed surfaces, cover-processed surfaces, and unimportant fixed joint surfaces without precision requirements that are not suitable for welding repair or plugging can also be filled with special epoxy resin fillers of similar colors and adhesive fixation (castings) The working temperature should generally not exceed 90℃)
Before filling, the defective parts should be mechanically treated by filing, scraping, sandblasting or cleaning with gasoline, acrylic copper and other solvents according to relevant regulations. If the casting requires stress relief annealing, it should be filled after annealing. 4 Inspection of welding repair quality
4.1 The cleaning of defective welding repair areas should be inspected one by one, and should be carried out in accordance with the requirements of 3.3.2.1b and 3.3.2.1d. 4.2 The welding repair method and welding rod used shall be in accordance with the relevant provisions of Article 3.3.2.1b and Article 3.3.2.1c. 4.3 After defective welding is repaired, the quality of each welding area should be inspected one by one to meet the requirements of Article 3.3.2.3. Check the hardness with a hammer or Shore hardness tester.
4.4 The number, size, area, etc. of defects in welding repairs shall not exceed the provisions of this standard. 4.5 Any crack-like defects on castings that are subject to large bending moments and torques under impact loads should be inspected using effective methods after welding repairs. 5 Acceptance
After the casting defects are repaired, they shall comply with the repair quality requirements in this standard or the ordering agreement, and shall be inspected and accepted in accordance with the regulations on casting quality in JB6887 "Technical Conditions for Castings for Fans". Additional notes:
This standard is proposed and coordinated by the National Technical Committee for Fan Standardization. This standard is drafted by Shaanxi Blower Factory; Shanghai Blower Factory, Wuhan Blower Factory, Shenyang Blower Factory, Shenyang Foundry, and Chongqing General Machinery Factory participate in the drafting
The main drafters: Wang Kuiwang, Song Lili, and Chao Chaoyen. 235
1. In individual cases, if defects such as pores, shrinkage holes, slag holes and hole diameter deviations are found in the machined surface of unimportant round holes in castings, the round holes of castings can be processed according to this standard without affecting the quality of the parts and the performance of the fans. After proper expansion, it is inlaid with human slips. 3.3.3.2 Technical requirements for key sets
a.
b.
心.
d.
e.
234| | tt | |tt||The sleeve should be fixed to the casting with seam screws. When the sleeve is subjected to axial force, it should be equipped with a sleeve with a boss; it is not allowed to be embedded with an eccentric sleeve, nor is it processed into an eccentric sleeve after the sleeve is inserted; two sleeves are not allowed to be embedded in the same hole.
Inner diameter of insert
80
>80～150
>150~～200
>200～500
JB/T 6889--93
Table 4
3.3.3.3 Important parts such as the main shaft hole, the oil tank and hydraulic parts hole, and the bearing cover hole must not be nested. 3.3.4 Fill
minimum wall thickness of the sleeve
10
15
mm
small defects (pores, pores, Blisters, slag inclusions, etc.) can be filled with epoxy resin special filler or putty without affecting the rigidity and appearance quality of the casting. Small defects on process-processed surfaces, cover-processed surfaces, and unimportant fixed joint surfaces without precision requirements that are not suitable for welding repair or plugging can also be filled with special epoxy resin fillers of similar colors and adhesive fixation (castings) The working temperature should generally not exceed 90℃)
Before filling, the defective parts should be mechanically treated by filing, scraping, sandblasting or cleaning with gasoline, acrylic copper and other solvents according to relevant regulations. If the casting requires stress relief annealing, it should be filled after annealing. 4 Inspection of welding repair quality
4.1 The cleaning of defective welding repair areas should be inspected one by one, and should be carried out in accordance with the requirements of 3.3.2.1b and 3.3.2.1d. 4.2 The welding repair method and welding rod used shall be in accordance with the relevant provisions of Article 3.3.2.1b and Article 3.3.2.1c. 4.3 After defective welding is repaired, the quality of each welding area should be inspected one by one to meet the requirements of Article 3.3.2.3. Check the hardness with a hammer or Shore hardness tester.
4.4 The number, size, area, etc. of defects in welding repairs shall not exceed the provisions of this standard. 4.5 Any crack-type defects on castings that are subject to large bending moments and torques under impact loads should be inspected using effective methods after welding repairs. 5 Acceptance
After the casting defects are repaired, they shall comply with the repair quality requirements in this standard or the ordering agreement, and shall be inspected and accepted in accordance with the regulations on casting quality in JB6887 "Technical Conditions for Castings for Fans". Additional notes:
This standard is proposed and coordinated by the National Technical Committee for Fan Standardization. This standard is drafted by Shaanxi Blower Factory; Shanghai Blower Factory, Wuhan Blower Factory, Shenyang Blower Factory, Shenyang Foundry, and Chongqing General Machinery Factory participate in the drafting
The main drafters: Wang Kuiwang, Song Lili, and Chao Chaoyen. 235
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