GB/T 23605-2020Determination of beta transus temperature of titanium alloys (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 23605-2009 "Method for determination of beta-transition temperature of titanium alloys".

Compared with GB/T 23605-2009, except for editorial changes, the main technical changes of this standard are as follows.

--- Removed the normative reference file GB/T 13298 (see Chapter 2, Chapter 2 of the 2009 edition);

--- Modify the element "Method Principle" to "Principle" and change "Primary Alpha" to "Primary Alpha Phase or Precipitated Alpha Phase" (see Chapter 4, 2009 Chapter 4 of the edition);

--- Modify the element "sampling requirements" to "samples" and modify the corresponding sample requirements (see Chapter 5, Chapter 5 of the 2009 edition);

--- Modified the element "test equipment requirements" to "instrument equipment" and modified the corresponding requirements (see Chapter 6, 2009 edition Chapter 6);

--- Modified the element "test conditions and requirements" to "test steps", and modified the interval between the heat treatment temperature of the sample and the holding time of the sample And quenching delay time requirements (see 7.1, Chapter 7 of the 2009 edition);

--- Removed the "recommended ordinary annealing after quenching" provisions (see 7.1.3 of the 2009 edition);

--- Modified the element "metallographic sample preparation and inspection requirements" to "test steps" and revised the corresponding requirements (see Chapter 7, 2009 Chapter 8 of the edition);

--- Increased the provisions for corrosion and inspection magnification of samples (see 7.2.2 and 7.2.3);

--- Modified the judgment method of beta-transition temperature and the expression of results (see Chapter 8, 9.1 of the 2009 edition);

--- Modify the element "inspection report" to "test report" and modify the corresponding content (see Chapter 9, Chapter 10 of the 2009 edition);

--- Amended Appendix B, and listed the typical quenching micrograph of beta-transition temperature judgment of alpha-type, alpha-beta-type and metastable beta-type titanium alloys (See Appendix B, Appendix B of the 2009 edition).

1 Scope

This standard specifies the principle of metallurgical method for the determination of beta-transition temperature of titanium alloys, samples, equipment, test procedures, determination of test results, And test report.

This standard applies to the use of metallographic methods to determine the beta-type, alpha-beta-type and metastable beta-type titanium alloys beta transition temperature.

2 Normative references

The following documents are essential for the application of this document. For dated references, only the dated version applies to this document. For undated references, the latest version (including all amendments) applies to this document.

GB/T 5168 Titanium and titanium alloy high and low magnification microstructure inspection method

GB/T 9452 Determination method of effective heating zone of heat treatment furnace

3 Terms and definitions

The following terms and definitions apply to this document.

4 Principle

alpha-type, alpha-beta-type and metastable beta-type titanium alloys all contain a certain number of primary alpha-phases after smelting, hot deformation, annealing and solution aging.

The aging phase precipitates an alpha phase. As the temperature increases, the alpha phase in the titanium alloy gradually decreases, and when it reaches a certain critical temperature, it will all transform into beta phase structure.

After the critical temperature is maintained for a certain period of time, rapid quenching can obtain acicular martensite or metastable beta-phase structure without alpha phase. Through view Check the metallographic structure of the sample after quenching at different temperatures according to the preset temperature interval to determine the beta-transition temperature of the titanium alloy.

5 Sample

5.1 Samples can be taken from any part of the product processing process, such as intermediate ingots such as ingots, rod billets, forging billets and slabs, or bars, plates For processed products such as wood, the same group of sample blanks should be taken from the same processing link of the product. If the product standard has requirements for sampling, Quasi-execution.

5.2 When cutting the sample, deformation and overheating should be avoided, and the surface to be tested of the sample should be able to better represent the entire cross-section structure of the material.

5.3 The sample should be a cylinder with a diameter of 10mm ~ 12mm and a height of 15mm, or a rectangular parallelepiped with a side length of 10mm ~ 12mm and a height of 15mm.

5.4 The number of samples in each group is usually five, which can also be appropriately increased or decreased.

5.5 Phase transition test of metastable beta-type titanium alloys in hot and solid solution state. If necessary, the sample blank should be heat treated first. TB2, TB3 are recommended The heat treatment system with TB5 is. After holding at 650 °C ± 10 °C for 1 hour, it is cooled to 550 °C ± 10 °C with the furnace and air-cooled.