A, stainless steel is easy to deformation of the eve of the x70 line pipe strength. Stainless steel in the process of cutting processing, because its elongation is inevitable, austenitic stainless steel is out of line, the eve of the plastic deformation will happen, it's about the difficulty of machining inevitably happened. Moreover, the strength of the stainless steel itself than the eve of the force, and the cutting of the eve of the double resistance, in the process of cutting force.
2, stainless steel high cutting temperature. Cutting the amount of the eve of will happen in the process of quantity of heat, but the stainless steel material and coefficient of thermal conductivity than weak, so the heat all focus on the cutting area and the blade, not easy heat dissipation. Third, cutting difficulty eve. Stainless steel is a hard material, good plasticity, toughness eve, but at an hour when machining, cutting because not easy to break, easy adhesion caused by cutting profile extrusion stainless steel, so the excessive wear, this is because the cutting tool wear, the knife surface potholes, forming small spalling and gap; With stainless steel hardness is very high, in direct contact with the tool when cutting, friction, abrasion cutting tools, and work hardening phenomenon, both can make the cutting tool wear), thus worsening machining stainless steel profiles. Fourth, the stainless steel easy expansion. Will happen in the process of cutting processing, quantity of the eve of the quantity of heat, resulting in stainless steel, the cutting of the eve of the difficulty.
Stainless steel in the process of drawing which defects can cause? What was the reason for the tensile crack and surface scratch? Below small make up take you know together:
Stainless steel deep drawing cracking happens sometimes after deep drawing deformation, sometimes within when drawing by die exit immediately; Sometimes after deep drawing deformation is subjected to impact or vibration occurs; Sometimes after deep drawing deformation after a period of storage or in use process happen.
Small stainless steel extension rate, modulus of elasticity uns c68700 is larger, hardening index is higher, thick anisotropic index r value is small (stainless steel is 0.9 ~ 0.11, the mild steel was 1.3 ~ 2.0). Stainless steel material from yield to failure of plastic deformation stage is short, especially its weighted value of the plastic strain ratio R is larger.
The causes of the formation of crack: cold work hardening of austenitic stainless steel high index (0.34) stainless steel.
The metastable austenitic stainless steel model, the uns c70600 deformation phase transition happens, the induced martensite phase. Martensite than brittle, so prone to cracking.
During plastic deformation,, with the increase of the deformation induced martensite content will also be increased with the increase of the deformation and residual stress. The induced martensite phase content is higher, the cause of residual stress is, the greater the during processing are also more prone to cracking.