Material is 35CrMoA or 40CrMoNn alloy forged steel. To get better fiber texture, we use electric stove for second forging, or deoxidation treatment. It is forged from three directions and the forging ratio is not less than 4.0:1.0. It can not have crack, impurity, looseness, overburns, etc. And weld is not allowed. It should be confirming to the stipulation of JB/TQ252-81, and should be checked by gradeⅢ After quenching the rough module will be rough processed, then the hull hardness is HB285-330.
Heat-treated and internally hardened for high durability; available in various materials to meet a wide range of applications; standard
one or two-piece configuration, with designs available for pressure of 5000psi(35.1Mpa), 7500psi(52.7Mpa), and 10000psi(70.3Mpa); discharge connections available on each side; suction connections on each side or front center. 
