Function: During drilling operation, casing head is an important equipment for controlling wellhead pressure. Raw Material: Carbon steel or low alloy steel comply with API Spec.6A. Applied Casing Program: 20"×13-3/8"×9-5/8"× 7"×5-1/2", or as user's requirements. Bottom Connection: welded type, slips type, thread type.Outlet connection: thread type, flange type(c/w VR plug thread).Technical SpecificationsNominal Dimension of Top Flange (in)11,13-5/8,20-3/4,21-1/4Working Pressure of Top Flange (MPsi)2,3,5,10Surface Casing Dimension(in)20,13-3/8,9-5/8,7Nominal Diameter of Side Outlet (in)2-1/16,2-9/16,3-1/81. Casing Head-Bottom Slip Connection Characteristics: (1) Connect surface casing by type WD slip. (2) Adopt type BT secondary seal structure. (3) Accurately calculate casing string's length is not necessary. (4) Can not be affected by surrounding environment, climate, etc. (5) Easy, rapid, safe and reliable in installation. Can apply to different sizes casing, such as: 30",20",13-3/8",12-1/4",9-5/8",7",5-1/2". Can apply to different sizes casing as:13-3/8",9-5/8",7",5-1/2"etc. We can manufacture a variety of bottom thread such as CSG, LCSG, BCSG, TM, for the connection between casing head and surface casing. 2. Casing Head-Bottom thread connection (1)Bottom of the casing head connects surface casing by various types of threads,such as CSG,LCSG,BCSG,TM,ETC. (2)Convenience and rapid in installation,safe and reliable in operation. 3. Casing Head-Bottom welded connection (1)Bottom of the casing head connects surface casing by welding. (2)There’s pressure test hole, which can test welding effect, in welding annular space. Bottom can be connected to surface casing by the method of sleeve welding.Pressure testing holes are designed for the test of welding effect.Applied Casing Program:20",13-3/8",9-5/8",7",5-1/2", etc.