When flaring 2520 Stainless steel pipe prone to cracks to why Φ45mm × 5mm specifications, for example, according to GB / T14976-2012 standard orifice need expanded its Φ57mm, (ratio = after flaring flaring flaring end surface than the outer diameter / before flaring nominal outside diameter) of 6.5, and a wall thickness of only 8mm, it is easy to appear in the flared crack or cracking.

At room temperature, stretching, bending and rolling state are generated strain-induced martensite, and 2520 stainless steel tube content with increasing cold deformation increases. A large number of experiments show that: in 2520 during deformation appears seamless to varying degrees split, deformation twins, strain-induced martensite, and in the vicinity of the grain boundary formation and annealing twins dislocation pile and dislocation cellular tissue.

 The organizational structure of the deformation hardening both contributions. The main purpose of seamless solution treatment is to eliminate the internal stress of the material and reduce the hardness, improved formability stainless steel seamless pipe. The high hardness values after treatment illustrate the difference between the softening effect of residual stress not fully released because the lattice distortion caused by residual stress also causes hardness change. It is because of the presence of residual stress, resulting in cracks in the stress concentration is easy to place when the stainless steel pipe flaring flaring thus affecting the performance. Since the bit to grain boundaries and grain boundaries on both sides of the difference, increasing the crystal dislocation slip resistance, so the main role of grain boundaries hinder dislocation motion. The finer the grain, the more grain boundaries impede dislocation slip effect is greater, the higher the yield strength of the steel pipe, forming a grain boundary strengthening, resulting in hardening; thus the smaller the grains in flaring more prone to work hardening.