Vickers hardness
The ability of the metal material to resist external force deformation adopts the load on the concave area of the unit indentation as the hardness value.
Summary of detection methods
Using a Vickers hardness tester, the indenter is pressed into the surface of the sample under a predetermined load, and the load is removed after a specified holding time. The Vickers hardness was calculated by measuring the diagonal length of the surface indentation and converting it into the indentation area.
Testing standard
GB/T4340.1
Drop hammer shear area SA%
DWTT (drop hammer tear test) is a test method mainly used to evaluate the crack arrest performance of brittle fracture. The drop weight shear area SA% is the ratio of the ductile fracture zone area of the sample section to the net section area of the fracture.
Summary of detection methods
The specimen in the state of simply supported beam is interrupted once by a drop hammer or pendulum of a certain height, and the percentage of the sheared area on the fracture surface of the fractured specimen is measured and evaluated.
Testing Standard
GB/T 8363, ASTM E 436
Inclusion level
In the steel making process, a small amount of slag, refractory material and reaction products in smelting are formed into the molten steel. According to the shape and distribution of inclusions, the inclusions are divided into several categories and graded according to length, quantity, etc., and the content, the degree of contamination and the type of non-metallic inclusions in the steel are reflected by rating.
Summary of Detection Methods
The inclusion sample is not corroded, generally magnified 100 times in the microscope, and tested with the specified field of view. Usually, the field of view with the most serious contamination of the inclusions is selected and compared with the corresponding standard rating chart of the steel.
Testing Standard
GB/T 10561, ASTM E45
Grain size grade
Grain size refers to the size of each grain. Related detection criteria are usually graded to differentiate their size.
Summary of Detection Methods
The grain size grade was evaluated by comparison with a standard rating chart under a microscope of prescribed magnification. A cut point method, an area method, and the like can also be employed.
Testing Standard
GB/T 6394, ASTM E112
Banded tissue
In the microstructure of hot-rolled low-carbon structural steel, ferrite grains and pearlite grains are arranged in parallel along the rolling direction, layered, and strip-shaped.
Summary of Detection Methods
Banded tissue grades were assessed against a standard rating map under a 100x microscope.
Testing Standard
GB/T 13299
Hydrogen induced cracking (HIC)
Resistance to hydrogen induced cracking corrosion test. It is used to test the hydrogen sulfide test method for the sensitivity of steel pipes to hydrogen ions in a hydrogen sulfide-containing environment. The evaluation indexes include crack sensitivity rate (CSR%), crack length ratio (CLR%), and crack thickness ratio (CTR%).
Summary of detection methods
Pipeline steel and pressure vessel steel In the environment containing an aqueous solution of sulfide, the method of evaluating the crack length and width by HIC due to corrosion hydrogen absorption.
Testing Standard
GB/T 8650 NACE TM 0284
Hydrogen Sulfide Stress Corrosion Test (SSC)
The ability of metals to resist special forms of cracking in hydrogen sulfide environments
Summary of Detection Methods
The stress corrosion test of a sample subjected to a certain load in an acidic environment containing hydrogen sulfide is based on the cracking of the sample without cracking.
Testing Standard
GB/T 4157 NACE TM 0177-2005
