What factors determine the service life of large blind flange

　　Due to the high viscosity and poor chip breaking performance of large blind flange material, it is easy to have chip scratch on the workpiece thread or screw tap chipping in the tapping process of ANSI B16.5 stainless steel Special Pipeline Blind flange, which affects the processing efficiency and thread quality. In order to prolong the service life of tap and improve the quality of thread processing,

　　On the steckel mill, the thermomechanical history of the whole length of the large blind flange changes obviously, especially in the production of the micro large blind flange, which will strongly affect the recrystallization degree, grain growth and precipitation on the finishing mill, and lead to the drastic change of the ultimate microstructure and function of the whole length of the large blind flange. The original geometric shape of the leading part must be maintained during grinding. It is better to use a tap spade grinding machine for grinding. The best way to solve the problem is to customize the tap with shorter base according to the specific requirements of the thread to be machined.

　　Large blind flange taps should be made of better taps. The wear resistance and toughness of tap can be significantly improved by adding special alloy elements to common high speed tool steel. The heat treatment method of cutting tool should be selected reasonably to take into account the hardness and toughness of tap. Increase the front angle of tap properly. However, it should be noted that if the front angle of the tap is too large, it is easy to cause the tap to break the edge and the tapped thread to have multiple edges when withdrawing the cutter. The wear resistance, heat resistance and lubricity of tap can be improved by coating titanium nitride on the surface of tap.