JB/T 9754-1999 This standard is a revision of NJ 431-86 "Technical Conditions for Welding Repair of Gray Iron Castings Defects". During the revision, only editorial changes were made according to relevant regulations, and the main technology remained unchanged. This standard specifies the scope, technical requirements, inspection methods and inspection rules for welding repair of gray iron castings for internal combustion engines. This standard applies to welding repair of several surface defects in gray iron castings for reciprocating internal combustion engines with a cylinder diameter of less than or equal to 200mm. This standard does not apply to welding repair of damage during the use of the machine. This standard was first issued in 1986. JB/T 9754-1999 Technical Conditions for Welding Repair of Gray Iron Castings for Internal Combustion Engines JB/T9754-1999 Standard download decompression password: www.bzxz.net

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Standard of the Machinery Industry of the People's Republic of China
JB/T9754—1999
Internal combustion engines Welding repair for grayiron casting defects--Specifications1999-09-17 Issued by the State Machinery Industry Bureau on January 1, 2000, implemented by JB/T9754-1999. This standard is a revision of N431-86 (Technical Specifications for Welding Repair of Gray Iron Casting Defects). The original standard was revised for major revisions, and the main technical content remained unchanged. This standard replaces N431-6 from the date of implementation. This standard was proposed and managed by the National Technical Committee for Standardization of Internal Combustion Engines. The drafting unit of this standard is Shanghai Internal Combustion Engine Research Institute. The main drafters of this standard are: This standard. Summary This standard was first issued in 2016. Scope Machinery Industry Standards of the People's Republic of China Technical Specifications for Welding Repair of Gray Iron Casting Defects in Internal Combustion Engines Technical Specifications for ... DefectsSpecificatonsJB/T9754—1999
Replacement NI431-86bzxz.net
This standard specifies the scope, technical requirements, inspection methods and inspection rules for welding repair of iron castings for internal combustion engines. This standard applies to the welding repair of several surface defects in solid iron parts with a diameter of less than 200mm for internal combustion engines, and is not applicable to the welding repair of parts that are partially damaged during the use of the machine. 2 References
The definitions contained in the following standards constitute the provisions of this standard through reference in this standard. The versions shown are all in effect when this standard is published. All standards may be revised, and parties using this standard should discuss the possibility of using the latest versions of the following standards. GA/T 231—[984
GD/T 2649—1981
GB/T 2651-1981
GE/T2654:1991
JB.T7945—1999
3 Technical requirements
King's hardness test method
Mechanical property test sampling method for welding joint
Welding joint tensile test method
Furnace joint and push welding metal hardness test method for gray casting defect mechanical property test method
3.! The scope of defects that cannot be welded and the scope of allowable welding repair are as follows: 3.1.1 Defects and parts that cannot be welded
1) Defects that cannot be welded: loose fins, dispersed sand inclusions (slag), etc.; b) Parts that cannot be welded: heating surface, fatigue surface, stress concentration and tender feeling area. 3.1.2 The scope of defects that cannot be welded
Any defects that are machined off on the machined surface, or do not exceed the table! The specified range shall be used and the range specified in 3.1. The area of ​​each narrow pore shall not exceed 300 m2. The evaluation and allowable range are specified in Table 1. 3.1.3 Range of defects allowed for welding repair
Except for those specified in 3.1.1 and 3.1.2, the size and characteristics of the defects of the castings that meet the following requirements can be welded repaired:
a) The defects of the castings of the diesel engine with a cylinder diameter of less than 160mm and other products shall be welded repaired according to the range specified in Table 2; b) The range of defects of the diesel engine castings with a cylinder diameter greater than 160~300mm shall meet the requirements of Table 3; c) When the depth of the defects in Table 2 and Table 3 exceeds the requirements, it shall be handled according to the provisions of the through hole; The State Machinery Industry Bureau approved the implementation of JB/T9754-1999 on September 17, 2000-01-01
d The cracks in Table 2 and the table include penetrating cold shut:! The defects of the single-cylinder diesel engine castings can be welded repaired, and the defects shall be repaired in accordance with the requirements of Table 2. Table
Aperture size
Casting plate type
One piece
Hole name
North surface
Haogong table
Non-processed table
Processed surface
Non-processed surface
Added mounting surface
Dense air holes
Nested air ducts
Harmful air holes
3.5-10 mm
(deepest)
e hov4
high side or
plus 1 hole
side distance
each 1
2 address
1) does not refer to pores, pinholes, follow-up holes, sand limits, eyes, etc., and the sunken defects such as shrinkage and fast meat are treated by hole suction (Table 2, Table 3 the same; 2! 104 means no more than 4 pores per 10mm length. 3]! Indicates the entire thickness of the defect [Table 2, Table 3 the same]. 4) is also the diameter (2. Table the same.
defect detection
goodness type
One defect
Defect name
Defect size
Length #30
Each two
Fast trap fee
Single defect
Overall defect
Part type
Defect will be called
Fast trap size
3.2 Technical requirements for fast trap coal filling
JB/T9754—1999
Fast reduction tariff
3.5~10mum
>10 mr
The welding repair of casting defects shall comply with the requirements of this standard. After welding repair, the technical performance shall not be reduced. 3.2.2
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Defect welding repair
The joint strength of the defect welding repair of the important stress-bearing parts of the casting shall not be lower than the strength requirements of the parent material. 3. 2.3
3.2.4 For castings with sealing requirements, release kerosene penetration or use other methods to test after welding. 3.2.5 For castings with pressure requirements, pressure test should be carried out according to the product drawing after welding. Single defect
body fast
3.2.6 For castings with surface repair, the total repair area should ensure the machining allowance: For castings with non-addition surface repair, the convex or concave value of the short repair area should meet the requirements specified in the product drawing. 3.7 After the casting is furnace repaired, its parent material The shape and size of the chain should meet the requirements specified in the product drawings. 3.2.8 After the welding of the parts, there should be no defects such as pores, slag inclusions, cracks, etc. 3.2.9
No color requirements are required for the welded parts. 3.2.10 No special requirements are required for the chain parts after welding, and no heat treatment is required. 3.2.11 After welding, the hardness of the machined surface of the chain parts should be able to ensure the durability of the processing; the hardness value after welding shall not exceed 269HBS. Before welding, the non-machined surface of the casting does not require hardness. 3.2. 12
4 Test method
4.1 Strength test
Test in accordance with the relevant provisions of JB/7945, GBT2649 and GB/T2651. 4.2 Sealing test
One side of the welded part is coated with self-powder, and the other side is permeated with fuel oil. The surface of the white powder is cut into a plain surface without any traces. 4.3 Hardness test
The test is carried out according to the relevant provisions of GB/T231 and GD2654. 5 Inspection rules
5.1 After the defects of the casting are welded, they shall be inspected by the quality inspection department of the manufacturer. 5.2 Tensile strength test, select 3 samples for testing. After all 3 samples meet the strength requirements of the parent material, the pieces can be welded. 3
5.3 Sealing should meet the requirements of 4.2.
5.4 Strength should meet the requirements of 3.2.5.
JR9754—1999
5.5 The measurement of the geometric shape and dimensional accuracy of the parent material after the casting is welded shall meet the requirements of 32.7. 5.6 The surface quality of the weld repair area of ​​the casting shall meet the requirements of 3.2.6 and 3.2. 5.7 After the defects of the casting are welded, if the hardness value of the surface of the weld repair area of ​​a casting exceeds the requirements of 3.2.11, the hardness of the parts in the batch shall be checked, and the unqualified castings shall be re-processed. The parts to be welded shall be inspected and accepted after they are qualified. 5.9 Under the conditions that the user complies with the provisions of the product manual, within the warranty period from the date of shipment from the manufacturer, if the casting is damaged or cannot work normally due to poor repair, the manufacturer shall repair or replace it for the user free of charge.
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