This standard specifies the grading principles and rating methods for the proportion of α phase and the grain size of cast brass. This standard is effectively used to evaluate the proportion of α phase and the grain size of cast brass. JB/T 5108-1991 Cast Brass Metallography JB/T5108-1991 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T5108—91
Cast Brass
Published on July 15, 1991
Implemented on July 1, 1992
Published by the Ministry of Machinery and Electronics Industry of the People's Republic of China
Metallurgy of Cast Brass of the People's Republic of China
Subject Content and Scope of Application
This standard specifies the classification principles and rating methods for the proportion of α phase of cast brass and the grain size of cast brass. This standard is applicable to the evaluation of the proportion of α phase of cast brass and the grain size of cast brass. 2. Cutting and Preparation of Specimens
2.1 Metallographic specimens are usually cut from tensile test bars. If there are special requirements, they can be cut according to the provisions of the technical documents. The metallographic specimens are coarsely and finely ground with metallographic sandpaper and then mechanically polished. If necessary, manual fine polishing can be performed. 2.23
JB/T5108--91
The polished metallographic specimen is etched with an aqueous solution of 5g ferric chloride, 10mL hydrochloric acid, and 100mL water at room temperature. 2.3
No heating or deformation is allowed during the cutting and preparation of metallographic specimens. 3 Microscopic examination
The proportion of α phase and the grain size of cast brass are evaluated with an optical microscope, and the magnification is 100 times. During microscopic examination, the entire inspected surface should be viewed first, and then the evaluation should be carried out according to the majority of the fields of view and the level chart. 3.2
In the same specimen, if there are grains of different sizes, the percentage of each grain should be estimated and noted in the report. 3. 3
Grading and rating chart of cast brass α phase
The proportion of α phase in cast brass is approximately divided into five levels: 10%, 20%, 30%, 40%, and 50%. The grading of the α phase ratio of cast brass is in accordance with Table 1. 4.2
Approved by the Ministry of Machinery and Electronics Industry on July 15, 1991
Implementation on July 1, 1992
JB/T5108--91
5 Grading and rating diagram of cast brass grain size JB/T5108-91
5.1 The grain size of cast brass is divided into eight grades according to the number of grains per unit area. 5.2
The grading of the grain size of cast brass is in accordance with Table 2. wwW.bzxz.Net
Number of grains per unit area
pieces/mm
Number of grains per area with a field of view diameter of 70mm
Magnification 100 times
Magnification 50 times
JB/T5108-91
Additional notes:
JB/T5108—91
This standard was proposed by the National Technical Committee for Standardization of the Ministry of Machinery and Electronics Industry. This standard is under the jurisdiction of the Shenyang Foundry Research Institute of the Ministry of Machinery and Electronics Industry. Figure 11
This standard was drafted by Shenyang Foundry and Shenyang Foundry Research Institute, and Dalian Marine Propulsion Plant, Dalian Institute of Technology, Zhengzhou Machinery Institute, Great Wall Machine Tool Foundry, Hudong Shipyard, Weishuyan Locomotive and Rolling Stock Technology Research Institute of the Ministry of Railways, Shanghai Xinyi Nonferrous Foundry and other units participated in the drafting
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