This standard specifies the technical requirements, inspection methods and microstructure classification of cast copper-lead alloy bearings for internal combustion engines. This standard is applicable to the inspection of the metallographic structure of cast copper-lead alloy bearings for internal combustion engines with a lead content of 20% to 33%. JB/T 9749-1999 Metallographic Inspection of Cast Lead-Copper Alloy Bearings for Internal Combustion Engines JB/T9749-1999 Standard download decompression password: www.bzxz.net

[CS 27.020
Machinery Industry Standard of the People's Republic of China
JB/T 9749—1999
Internal combustion engine
Cast copper lead bearings.--Metallographic examination
Internal combustion engineg-- Cast copper lead bearings.--Metallographic examination1999-09-17 Issued
State Bureau of Machinery Industry
2000-01-01 Implementation
JE/T 9749—1999
This standard is a revision of NI355--85 "Metallographic Examination of Cast Steel-Lead Alloy Bearings for Internal Combustion Engines". Editorial modifications were made to the original standard during the revision, and the main technical contents remained unchanged. This standard replaces NJ355-85 from the date of implementation. This standard is issued 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 drafter of this standard is Du Rong.
This standard was first issued on March 21, 1985. Scope
Mechanical Industry Standard of the People's Republic of China
Cast copper-lead alloy bearings for internal combustion engines
Metallographic examination
Internal combustion enginesCast coper-lead bearings--Metallographic examinationIB/T9749—1999
Replaces N) 355—83
This standard specifies the technical requirements, inspection methods and classification of microstructure for metallographic inspection of cast copper-lead alloy bearings for internal combustion engines. It is applicable to the inspection of metallographic structure of cast copper-lead alloy bearings for internal combustion engines with a lead content of 20%~33%. Technical requirements
The microstructure of copper-lead alloy should be that the lead-rich phase (hereinafter referred to as lead) is evenly distributed in the α copper matrix in the form of dots and blocks; or the lead is evenly distributed between the & branches; and the lead is distributed in the copper matrix in the form of fine broken wool mesh. The combination of the alloy layer and the steel back should be good. 2.1 When the lead in the alloy layer microstructure is in the form of dots, blocks or spheres, it shall be evaluated according to the point and block structure level diagram of this standard. Levels 1-4 are qualified and level 4 is unqualified.
2.2 When the lead in the alloy layer microstructure is distributed between the α copper dendrites, it shall be evaluated according to the dendrite structure level chart of this standard, and 1~4 levels shall be qualified, and more than 4 levels shall be unqualified.
2.3 When the lead in the alloy layer microstructure is in the form of a network, it shall be evaluated according to the network structure level chart of this standard, and 1-2 levels shall be qualified, and more than 2 levels shall be unqualified. 2.4 The bonding between the alloy layer and the steel back shall be evaluated according to the bonding layer level chart of this standard, and 1~2 levels shall be qualified, and 3-5 levels shall be unqualified. 3 Inspection method
3.1 Sampling position
Two specimens shall be cut from the center between the edges at 30° to the side of the center of the bearing shell. The sampling position is shown in area A in Figure 1. A—Sampling location
Schematic diagram of sampling location
Approved by the State Machinery Industry Bureau on September 17, 1999 and implemented on January 1, 2000
3.2 Age inspection location
JB/T 9749—1999
Of the two specimens, one has the working surface as the metallographic grinding surface, and the other has the cross section (the long side of the A area in Figure 1) as the metallographic grinding surface. 3.3 Display of microstructure
Etch with 2%-4% nitric acid alcohol solution for 3~6 hours. If necessary, etch with iron oxide and hydrochloric acid aqueous solution (5 parts of iron trifluoride, 10 parts of hydrochloric acid, 100 parts of water) for 4~85 hours. 3.4 Magnification
The evaluation of various organizational levels is carried out at a magnification of 1 times. 3.5 Rating methodwww.bzxz.net
3.5.1 When evaluating the distribution of lead, the 5 worst fields of view can be selected from the two grinding surfaces of the working surface and the horizontal surface, and rated separately, and then the arithmetic mean is taken as the final grade. However, among the 5 fields of view, only 2 fields of view are allowed to exceed the qualified level. Note: The arithmetic mean of the 5 standard field levels can be rounded up to integers if there is a decimal level. 3.5.2 When evaluating the bonding between the alloy layer and the steel back, the worst field of view should be selected as the basis for rating. 4 Grading standards for microstructures
4.t Grading standards for point, block or spherical structures See Table 1 for the description of the microstructure levels.
Microstructure condition
Fine dots, spherical lead are evenly distributed in the solid body, small dots, blocky lead are evenly distributed in the copper solid body, medium-sized dots, blocky lead are evenly distributed in the α steel solid solution, large dots, blocky or spherical lead are evenly distributed in the solid solution, large dots, blocky lead are distributed in the copper solid body. The classification standard of dendritic structure in copper solid body
The microstructure level description is shown in Table 2.
Network structure classification standard
αCopper solid solution is in the form of fine dendrites, and lead is evenly distributed between dendrites. Copper solid solution is in the form of small dendrites, and lead is evenly distributed between dendrites. Copper solid solution is in the form of medium-sized dendrites, and lead is evenly distributed between dendrites. (Pin solid solution is in the form of large crystals, and lead is evenly distributed between dendrites. Copper solid solution is in the form of large crystals, and lead is unevenly distributed between dendrites. The microstructure level description is shown in Table 3.
JB/T9749-—1999
Microstructure description
Lead is a fine discontinuous network, evenly distributed at the grain boundaries of the solid solution. 1Lead is a fine discontinuous network, evenly distributed at the grain boundaries of the solid solution. Distributed on the grain boundary of copper solution, the lead is distributed in a trace network on the boundary of α steel solid solution. The alloy layer and the steel back are bonded in the standard 4.4
Bonding layer level description is shown in Table 4.
Good bonding
Bonding condition
Good bonding, there is a medium-wide solution on the interface between the steel back and the alloy, there is a poor bonding, there are impurities on the interface between the steel back and the alloy, there is a poor bonding, there are long inclusions on the interface between the steel back and the alloy, there is a poor bonding, there is continuous lead segregation parallel to the steel back, see Figure 2~Figure 6. a)
Figure 32 level
JB/T 9749-1999
Figure 43 level
Figure 54 level
Figure 65 level
4.6 Dendritic structure level diagram (100×) See Figure 1~Figure 11. b)
JB/T 9749—1999
Figure 82nd level
Figure 93rd level
JB/T9749-1999
Figure 5th level
Network level diagram (100×) See Figures 12 to 14. Figure 121st level
4.8Joint layer level diagram (100×) See Figures 15 to 19Figure
Figure 162nd level
Figure 1%4th level
JB/T 9749—1999
Figure 195th level
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