Fluid end and method of manufacturing it

A method of manufacturing a fluid end comprising a main block and a flange, the main block having a first and a second surface, the first surface being the surface of the main block nearer the flange and the second surface being the surface of the main block away from the flange, wherein the fluid end has assembly and non-assembly surfaces, wherein a first direction is defined extending between the block and the flange, and a second direction is defined extending perpendicularly to the first direction, the method comprising the steps of:

• a. forging of an ingot into a billet using open die method;
• b. forging the billet in a closed die by providing blows in multiple steps to form the flange and the main block with the first surface and the second surface and produce a near net shaped fluid end in as-forged condition, wherein a neck is formed between the flange and the main block in the first direction, and wherein the flange extends outwardly from the neck in the second direction;
• c. rough machining a portion of at least one of the first surface and the second surface of the main block of the near net shaped fluid end to form rough machined surfaces while leaving another portion of the same of the at least one of the first surface and the second surface having the portion that was rough machined in as-forged condition to produce a rough machined near net shaped fluid end;
• d. providing heat treatment to the rough machined near net shaped fluid end to produce a heat treated rough machined near net shaped fluid end;
• e. providing further semi-finish or partial or rough machining to the rough machined surfaces of the heat treated rough machined near net shaped fluid end to produce further machined surfaces while leaving the another portion of the at least one of the first surface and the second surface in as-forged condition;
• f. drilling the fluid end to create internal pathways therethrough;
• and
• g. providing finish machining to the further machined surfaces to produce the assembly surfaces of the fluid end, wherein the another portion constitute the non-assembly surfaces.