Impact test of precision steel pipe

By impact test different metal mild steel, steel and other industrial iron and T8 impact absorbed energy at different temperatures, the determination of low-carbon steel ductile-brittle transition temperature, relatively ductile-brittle transition metal observed characteristics.

Toughness is the ability of the material to absorb energy in the elastic deformation, plastic deformation and fracture process. Good material toughness will not suddenly brittle fracture under service conditions, so that security is guaranteed. The measurement principle of impact energy before impact energy in the form of potential energy of the pendulum in the part of the specimen in the course of fracture by the impact of post-absorbed. The starting height of the pendulum with its punch after the break between the sample reaches the maximum height difference can be directly converted into energy thrust samples consumed during the sample absorb impact energy function is called (AK) .

Pendulum with a series of predetermined height at different temperatures Charpy notched specimens state hit a one-time, measure the impact of each specimen broken absorbed energy. Changing the test temperature, a series of tests to determine the impact of the material from the human-to-brittle transition temperature range, referred to as “shock test.” Ductile-brittle transition temperature is Ak Ak-T curve was significantly lower temperature. The impact of significant changes in the power curve in the middle part is called the transformation zone, brittle and plastic regions each accounted for 50% when the temperature is called the ductile-brittle transition temperature (DBTT). When the crystals or cleavage fracture like brittle zone reached 50%, the corresponding temperature is called the fracture surface transition temperature (FATT).

1. brittle fracture: fracture at low temperatures the material will show brittle fracture, brittle fracture is a fast break, fracture process to absorb low energy before fracture and fracture process is accompanied by a lack of clear plastic deformation.

2. The ductile-brittle transition: Materials in a limited temperature range, subject to considerable change the energy absorbing shock loads fracture will occur. This phenomenon is called ductile-brittle transition material.

3. cleavage fracture: When the applied normal stress reaches a certain value, fast along the specific plane produced by a phenomenon known as transgranular cleavage fracture; basic microscopic characteristics of cleavage fracture is the stairs, rivers, and other snake-like pattern.

4. The whole fracture toughness: fracture crystalline area as a percentage of 0%; full of brittle fracture: fracture crystalline area as a percentage of 100%;

5. ductile-brittle-type fracture: fracture crystalline area percentage microscope measurements required to observe the specimen under the microscope fracture fracture surface, brittle fracture was part of the general distribution of light and dark spots of no return, can be calculated by measuring the results of brittle fracture trapezoid area.

Post time: Sep-25-2019