GB/T 13305-2024Method for determining content of the alpha-phase in stainless steels (English PDF)

Foreword

This document was drafted in accordance with the provisions of GB/T 1.1-2020 "Directives for standardization - Part

1.Rules for the structure and drafting of standardizing documents". This document replaces GB/T 13305-2008 " Method for determining content of the alpha- phase in stainless steels". Compared with GB/T 13305-2008, in addition to structural adjustments and editorial changes, the main technical changes are as follows:

a) ADD the term and definition of "alpha-phase in stainless steel" (see Chapter 3);

b) CHANGE the schematic diagram of steel sampling method (see Figure 1; Figures 1 ~ 5 of the 2008 edition);

c) ADD the corrosion method of cupric chloride hydrochloric acid alcohol solution [see 4.3a)];

d) ADD the mean value, standard deviation, confidence level, relative error formula for the determination of alpha-phase content in austenitic-ferritic duplex stainless steel (see 5.2.1.2;

4.1.2 of the 2008 edition);

e) CHANGE the magnification of the determination of alpha-phase content in austenitic stainless steel (see 5.2.2.1;

4.1.1 of the 2008 edition);

f) CHANGE the comparison method rating limit table for the determination of alpha- phase content in austenitic stainless steel (see 5.2.2.1;

4.1.1 of the 2008 edition);

g) ADD the table of alpha-phase types and contents in austenitic-ferritic duplex stainless steel (see 5.2.2.2);

h) ADD the key operating instructions and calculation formulas for the quantitative grid determination method (see 5.2.3);

i) ADD the key operating instructions for the automatic image analysis determination method (see 5.2.4);

1 Scope

GB/T 13305-2024 is the Chinese national standard on method for determining content of the alpha-phase in stainless steels, in the field of metallurgy. The /T suffix marks it as a recommended standard: it is not compulsory by itself, but it becomes binding as soon as a contract, a tender or a customer specification calls it up - which in practice is how most foreign buyers meet it. It was issued on 28 May 2024 by the State Administration for Market Regulation; Standardization Administration of China, and has been in force since 1 December 2024. Classification: ICS 77.040.99, CCS H24. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This document specifies the selection and preparation of specimens for the determination of alpha-phase content in stainless steel, the determination method, the test report. This document is applicable to the determination of alpha-phase content in austenitic stainless steel and austenitic-ferritic duplex stainless steel.

2 Normative references

The contents of the following documents constitute essential clauses of this document through normative references in the text. Among them, for dated references, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies to this document.

GB/T 1954 Methods of measurement for ferrite content in austenitic Cr-Ni stainless steel weld metals

GB/T 13298 Inspection methods of microstructure for metals

GB/T 15749 Measuring method in quantitative metallography

GB/T 18876.1 Standard practice for determining the metallographical constituent and inclusion content of steels and other metals by automatic image analysis - Part

1.Determining the inclusion or second-phase constituent content of steels and other metals by automatic

GB/T 30067 Standard terminology relating to metallography YB/T 4402 Micrographic method for determining content of delta-ferrite in martensitic stainless steel

3 Terms and definitions

The terms and definitions defined in GB/T 30067 and the following terms and definitions apply to this document. 3.1 alpha-phase in stainless steel The ferrite phase in stainless steel, which has a body-centered cubic (bcc) crystal structure.