Bimetallic Tube Manufacturing via Diffusion Bonding and Flowforming
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Solution Overview
Problem
The high cost of solid wall Corrosion Resistant Alloy (CRA) tubulars limits their use in downhole applications due to severe CO2 and H2S environments, necessitating a more cost-effective solution for corrosion resistance and structural integrity.
Innovation Solution
A two-step process involving diffusion bonding and cold flowforming to create bimetallic tubular components, where dissimilar metals with different cold deformation resistances are metallurgically bonded and then flowformed into long lengths, providing a clad or bimetallic tube with enhanced corrosion resistance and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid wall CRA tubulars are used to provide corrosion resistance in severe CO2 and H2S environments, then corrosion resistance is improved, but cost increases significantly
Solution Approach 1:
The patent applies composite materials by creating a bimetallic tubular structure consisting of a CRA inner liner (providing corrosion resistance) and a carbon steel outer tube (providing structural integrity). This composite structure combines the advantages of both materials, achieving the corrosion resistance of solid CRA tubulars while reducing cost by using less expensive carbon steel for the outer layer that does not contact corrosive fluids.
2Ease of manufacture
If clad tubulars with CRA liner and carbon steel outer tube are used to reduce cost, then cost decreases, but manufacturing complexity increases due to bonding dissimilar metals with different cold deformation resistances
Solution Approach 1:
The patent applies preliminary action by performing diffusion bonding of the CRA liner to the carbon steel outer tube before any cold forming operations. This sequence is critical because bonding the dissimilar metals first creates a unified structure that can then be cold formed as a single unit, avoiding the much greater complexity of attempting to bond pre-formed clad tubes afterward.
Solution Approach 2:
The patent applies parameter changes by controlling the cold deformation parameters during flowforming to accommodate the different properties of the two metals. The process uses reduced deformation rates and controlled reduction percentages to prevent delamination at the bonded interface while achieving the desired final dimensions, thereby managing the complexity of working with dissimilar metals.
3Strength
If diffusion bonding is used to bond dissimilar metals, then structural integrity is improved, but manufacturing time increases due to the multi-step process
Solution Approach 1:
The patent applies merging by combining the diffusion bonding process with the subsequent cold forming operations into an integrated manufacturing sequence. The bonded bimetallic structure is flowformed in one continuous operation after bonding, rather than assembling pre-formed components, which reduces the total number of manufacturing steps and overall production time while maintaining the structural integrity provided by diffusion bonding.
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
This method offers significant cost savings while maintaining the corrosion resistance and strength requirements for downhole applications, enabling the use of bimetallic tubulars in previously uneconomical regions for oil and gas production.
Implementation Method 1
diffusion bonding the inner diameter of the first tubular workpiece to the outer diameter of the second tubular workpiece
Data Source
AI summary
A method of producing a bimetallic tubular component includes providing a first tubular workpiece having an inner diameter and a second tubular workpiece having an outer diameter. The first and second tubular workpieces have dissimilar cold-working processing parameters. The method further includes diffusion bonding the inner diameter of the first tubular workpiece to the outer diameter of the second tubular workpiece, and flowforming the diffusion bonded tubular workpieces to form the bimetallic tubular component.