BOP Bonnet Closed-Die Forging With Flange Parting Line Control
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Solution Overview
Problem
Existing BOP bonnets lack optimal strength and efficiency in production, with prior methods like machining and casting resulting in material waste and strength inconsistencies, while closed die forging facilities are not readily available or effective for producing high-strength bonnets.
Innovation Solution
A closed die forging method is employed to create a BOP bonnet with the parting line positioned within the flange, optimizing grain flow and material properties for superior strength, allowing for efficient production with reduced material waste and increased strength through elongated material movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If machining a block of steel is used to create a BOP bonnet, then the outer shape can be created, but it requires a great deal of time and wastes a lot of material
Solution Approach 1:
The patent changes the manufacturing process parameter from machining (subtractive) to closed die forging (formative). The metal is heated to a malleable state and forged into the bonnet shape, which creates the outer shape with minimal material waste while maintaining manufacturing precision through the die-formed geometry.
2Productivity
If casting is used to create a BOP bonnet housing, then production efficiency is improved, but the resulting parts have strength inconsistencies due to uneven cooling rates
Solution Approach 1:
The patent changes the phase transition method from casting (liquid to solid with uneven cooling) to forging (solid state deformation). The metal is heated to above its recrystallization point and then forged, which eliminates the strength inconsistencies caused by uneven cooling rates while maintaining production efficiency.
Solution Approach 2:
The patent employs closed die forging with specially designed dies that impart the desired bonnet shape through compressive forces. This formative process creates uniform grain structure and consistent strength throughout the part, unlike casting which produces directional solidification patterns and strength variations.
3Strength
If closed die forging is used to create a BOP bonnet, then material strength is significantly improved, but the parting line location affects grain flow and overall strength
Solution Approach 1:
The patent strategically positions the parting line asymmetrically within the flange area rather than at the center or along symmetry planes. This asymmetric positioning allows the grain flow to follow optimal paths through the critical load-bearing areas of the bonnet, maximizing material strength while accommodating the constraints of closed die forging.
Solution Approach 2:
The patent optimizes the parting line location specifically within the flange region, which is a non-critical area for grain flow continuity. This local optimization allows the grain flow to remain uninterrupted through the end caps and cylinder while still enabling feasible die design and flash removal in the flange area.
4Strength
If closed die forging facilities are made available, then high-strength BOP bonnets can be produced, but the initial setup and die complexity increase
Solution Approach 1:
The patent divides the bonnet into sections that can be formed by separate die halves, with the parting line positioned in the flange where it can be accommodated. This segmentation allows the complex geometry to be achieved through modular die design, making the process feasible with standard closed die forging facilities while maintaining high strength through optimized grain flow in critical areas.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in a higher strength BOP bonnet with optimized grain flow, reducing manufacturing time and costs, and enabling mass production, while maintaining superior mechanical properties.
Implementation Method 1
heating a metal billet or ingot to a malleable state
Implementation Method 2
pressing or hammering it into the required shape using compressive forces
Implementation Method 3
The flash cools more rapidly than the rest of the material. This cooled metal is stronger than the metal in the die
Data Source
AI summary
A closed die method and resulting apparatus comprising a forged BOP bonnet with two end caps, a cylinder therebetween and a flange that interconnects the two end caps and the cylinder where a parting line created between the two dies is formed within the flange or at least near the flange of the BOP bonnet. This process optimizes grain flow and material properties for superior strength of the BOP bonnet.