Threaded Flange 
This flange is referred to as either threaded or screwed. It is used to connect other threaded components in low pressure, non-critical applications. No welding is required.
Standards: ANSI B16.5: 150LB, 300LB, 600LB
DIN: 2565 PN6, 2566 PN10
UNI: 2253 PN6, 2254 PN16
Materials: Carbon steel, stainless steel and alloy steel.