The impact absorption of different metals such as low carbon steel, industrial pure iron and T8 steel at different temperatures was measured by impact test. The ductile-brittle transition temperature of low carbon steel was measured and the transition properties of the metal were obtained .
Toughness is the ability of a material to absorb energy during elastic deformation, plastic deformation, and fracture. The toughness of the material does not suddenly occur under the service conditions , so that safety is guaranteed .
The principle of measurement of impact absorption work is that a part of the energy existing in the form of pendulum potential energy before impact is absorbed by the sample during the fracture after being impacted . The difference between the starting height of the pendulum and the maximum height it reaches after the sample is broken can be directly converted into the energy consumed by the sample during the breaking process . The work absorbed by the sample is called the impact energy .
A series of impact specimens of a series of simply supported beam at different temperatures were subjected to a one-time strike with a pendulum of a predetermined height to measure the impact absorption work of each sample when it was broken. The test temperature is varied and a series of impact tests are performed to determine the temperature range at which the material transitions from human to brittleness, referred to as the "impact test." The ductile-brittle transition temperature is the temperature at which the Ak value on the Ak-T curve is significantly lowered. The middle portion where the curve impact energy changes significantly is called the conversion zone, and the temperature at which the brittle zone and the plastic zone each account for 50% is called the ductile-brittle transition temperature . When the crystallization or cleavage-like brittle zone on the fracture reaches 50% , the corresponding temperature is called the fracture morphology transformation temperature .
1. Brittle fracture : The material