hemispherical head with thick wall: 1.standard:GB/T 25198-2010, ASME VIII 2.technic: ... forged 3.material:carbon steel hemispherical head with thick wall : 1.diameter:300-4400mm2.thickness:3-150mm3.straight flange:40 ... ,such as petroleum , chemical industry , boiler, pressure vessels , railway transportation, metal structure, water supply facilities and aerospace engineering, etc.No cracks ...