4. Material:
Stainless steel: A403 wp304, A403 wp304L, A403 wp316, A403 wp316L, A403 wp321 and so on.
Carbon steel: A234 wpb, st37.2, st35.8, API 5L GR B, API 5L X52, API 5L X60, API5L X65, API 5L X70 and so on.
Alloy steel: Wp11, wp22, wp12, wp5, wp9, wp91, 16Mo3 and so on.