JB/T 8892-1999 This standard specifies the metallographic structure level, inspection and evaluation method of rare earth eutectic aluminum silicon alloy piston after heat treatment. This standard is applicable to the inspection of the metallographic structure of rare earth eutectic aluminum silicon alloy piston of reciprocating internal combustion engine with cylinder diameter less than or equal to 200mm. This standard is published for the first time. JB/T 8892-1999 Metallographic inspection of rare earth eutectic aluminum silicon alloy piston of internal combustion engine JB/T8892-1999 standard download decompression password: www.bzxz.net

[CS 43.060.10;27.020
Machinery Industry Standard of the People's Republic of China
JB/T8892-1999
Internal eombustion engines.-Metallographic inspection forpiston of eutectic AlSi-RE alloy1999-09-17 Issued
National Bureau of Machinery Industry
2000-01-01Implementation
JBIT 892 -1999
This standard is proposed and managed by the National Technical Committee for Standardization of Internal Combustion Engines. The drafting organizations of this standard are: Shanghai Internal Combustion Engine Research Institute, Shandong Qixia Piston Factory, Shanghai Kolbenschmidt Piston Co., Ltd., and Zhejiang Wancha Aluminum Co., Ltd.
The main drafters of this standard are Li Gan, Liu Yinqing, Wang Dingguo and Xu Xiaofei. Machinery Industry Standard of the People's Republic of China
Metallographic inspection for piston of eutectic AI-Si-RE alloy for internal combustion engines
Metallographic inspection
Internal combustion engiaesMetallographic inspection for piston of eutectic AI-Si-RE alloy1Scope
JB/T8892—1999
This standard specifies the metallographic structure level, inspection and evaluation method of rare eutectic AI-Si alloy (referred to as 66-alloy) piston after heat treatment.
This standard is applicable to the inspection of metallographic structure of rare eutectic AI-Si alloy piston of reciprocating internal combustion engine with cylinder diameter less than or equal to 200m
Cited Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is released, the version 4 shown is valid. All standards will be revised. All parties using this standard should explore the possibility of using the latest version of the following standards. JB/T6289-1992 Metallographic inspection of cast aluminum pistons for internal combustion engines 3 Technical requirements www.bzxz.net
3.1 Microstructure
3.1.1 Aluminum-silicon rare earth compound content
Aluminum-silicon rare earth compounds are granular, blocky and strip-shaped, distributed on α-solid solution and silicon eutectic structures. According to Table 1 and the aluminum-silicon rare earth compound microstructure level chart, 1 to 4 levels are qualified, and more than 4 levels are unqualified. Table
Aluminum-silicon rare earth compounds
Aluminum-silicon rare earth compounds are in granular and small blocks, and are evenly distributed. Aluminum-silicon rare earth compounds are in small blocks, a small amount of fine blocks, and are evenly distributed. Aluminum-silicon rare earth compounds are in tea shape, some are in blocks, and the distribution is relatively even. Aluminum-silicon rare earth compounds are in strip shape, the longest is 0.13 \m, and the number shall not exceed 3. A small amount is in blocks, and the distribution is relatively even. Aluminum-silicon rare earth compounds are distributed in long strips
Aluminum-silicon rare earth compounds are distributed in a large number of long strips. 3.1.2 The eutectic structure of the solid solution and its silicon
should be a eutectic structure of fine solid solution and silicon. The eutectic silicon should be in the form of small dots and small strips. There should be no obviously poorly modified strip silicon, large pieces of primary silicon or coarse α-solid solution, and overburning and cracks are not allowed. According to the third level diagram of JB/T 6289-1992 Guohao Machinery Industry approved on September 1, 2000 and implemented on January 1, 2000
JB/T 8892-1999
, 1-4 levels are qualified, and more than 4 levels are unqualified. 3.1.3 Fishbone iron inclusions
It is allowed to have a moderate amount of evenly distributed fishbone iron inclusions, but there must not be a large number of large or concentrated fishbone iron inclusions. According to the sixth level diagram of JB/6289-1992, 1~4 levels are qualified, and more than 4 levels are unqualified. 3.2 Macroscopic organization level
Macroscopic organization defects only refer to pinholes and looseness in cast aluminum pistons, collectively referred to as holes. According to the first and second level diagrams of JB/T6289-1992, 1~4 levels are qualified, and more than 4 levels are unqualified. 4 Inspection method
4.1 Sampling location
Cut a longitudinal specimen at the center of the piston top [see Figure t. A-Microscopic sampling location
4. 2 Etching method
Etching with 0.5% hydrochloric acid aqueous solution or mixed acid aqueous solution, the etching time is 5~15s. The mixed acid ratio is as follows; Hydrofluoric acid (HF): 0.5mL:
HCI: 1.5 mL:
Nitric acid (HNO,: 2.5 mL:
Water (H,O >: 95.5 mL
4.3 Evaluation method
4.3.1 According to the relevant grade chart specified in this standard, make a comparative evaluation. 4.3.2 Divide the sample from the top to the center (half the thickness of the top) into 5 areas on average. Find the worst visual field in each area to evaluate the grade of the area. The arithmetic mean of the grades of the 5 areas is used as the grade of the sample. Only 2 areas out of the 5 areas are allowed to exceed the qualified grade. Note: If a decimal appears when averaging the 5 areas, the grade will be moved back. If the average result is 5.1, it will be rated as 6. 5 Microstructure grade chart of aluminum silicon rare earth compound (magnified 100 times) Microstructure grade chart of aluminum silicon rare earth compound is shown in Figure 2-Figure 7. 2
8892-1999
Figure 32 Grade
Figure 43 Grade
TBT8892-1999
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