GB/T 7216-2023 Metallographic test for gray cast iron
1 Scope
This document specifies the specimen preparation, test items and standard diagram, result presentation, and test reports for the metallographic test for gray cast iron.
This document is applicable to the assessment of the microstructure of gray cast iron.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 5611 Foundry terminology
GB/T 13298 Inspection methods of microstructure for metals
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 5611 and the following apply.
3.1
graphite length
maximum straight-line distance between any two points on the contour of a graphite sheet
4 Specimen preparation
4.1 The metallographic specimen shall be taken from test blocks or castings, and the test surface shall not be taken from the casting surface.
4.2 The metallographic specimen shall be prepared in accordance with the requirements of GB/T 13298. During the process of cutting and preparing the metallographic specimen, measures shall be taken to prevent changes in the microstructure, graphite peeling, and graphite dragging. The surface of the specimen shall be smooth and free from coarse scratches.
Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Specimen preparation 5 Test items and standard diagrams 6 Expression of results 7 Test report Annex A (Informative) Comparison of clause/subclause numbers between this document and ISO 945-1: 2019 Annex B (Informative) Technical differences between this document and ISO 945-1: 2019 and their causes Annex C (Informative) Examples of the distribution forms of typical flake graphite Annex D (Informative) Image analysis for identifying graphite forms Annex E (Informative) Phosphorus eutectic forms
