Nickel Alloy Clad Steel Pipe Extrusion
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Solution Overview
Problem
The production of nickel alloy clad steel pipes faces issues with delamination and surface defects due to the differential resistance to deformation between the nickel cladding and the carbon steel or low alloy steel parent material, which is exacerbated by the high temperature strength of nickel alloys, making it difficult to achieve uniform extrusion and corrosion resistance.
Innovation Solution
A method involving a composite billet with a nickel alloy cladding and a steel parent material, where the nickel alloy cladding has a specific composition with niobium to increase its solidus temperature, allowing for higher extrusion temperatures and reduced flow stress, thereby minimizing defects and enhancing ductility, and heat treatment processes such as solution annealing and tempering are applied to achieve desired mechanical and corrosion properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the nickel cladding material has high resistance to deformation (high temperature strength), then corrosion resistance is improved, but delamination and surface defects occur during extrusion
Solution Approach 1:
The patent modifies the chemical composition parameters of the nickel cladding alloy, specifically limiting carbon to 0.035% maximum, silicon to 0.35% maximum, and nitrogen to 0.03% maximum, while controlling their combined effect (carbon + nitrogen + 1/10 silicon < 0.035%). These parameter changes reduce the high-temperature strength and deformation resistance of the nickel alloy, allowing it to be extruded without delamination or surface defects while maintaining adequate corrosion resistance.
2Manufacturing precision
If the heating temperature of the billet is increased to reduce deformation resistance, then extrusion defects are reduced, but intermetallic compounds melt causing degradation in pipe formation
Solution Approach 1:
The patent changes the chemical composition parameters of the nickel cladding alloy to control its solidus temperature. By limiting carbon to 0.035% maximum and controlling the combination of carbon, nitrogen, and silicon, the solidus temperature is maintained above the extrusion temperature. This allows the billet to be heated to sufficiently high temperatures to reduce deformation resistance and eliminate extrusion defects, while preventing intermetallic compounds from melting and degrading pipe formation.
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 enables the commercial-scale production of clad pipes with improved extrusion behavior, reduced surface defects, and enhanced corrosion resistance, while avoiding the need for complex temperature control and additional processing steps.
Implementation Method 1
The composite billet is heated to an extrusion temperature of 1121-1260° C. (2050-2300° F.) and extruded
Implementation Method 2
the nickel alloy cladding has a specific composition with niobium to increase its solidus temperature, allowing for higher extrusion temperatures
Implementation Method 3
heat treatment processes such as solution annealing and tempering are applied to achieve desired mechanical and corrosion properties
Data Source
AI summary
A method of producing a nickel alloy clad steel pipe including: providing a hollow cylinder of nickel alloy cladding material and a hollow cylinder of steel, placing the hollow cylinder of the nickel alloy cladding material concentrically inside the hollow cylinder of steel or the hollow cylinder of the steel concentrically inside the hollow cylinder of nickel alloy cladding material to form a composite billet, heating the composite billet to 1121-1260° C., and extruding the composite billet, wherein the nickel alloy cladding material comprises 6.0-12.0 wt. % molybdenum, 19.0-27.0 wt. % chromium, 1.0 wt. % maximum tungsten, 0.6 wt. % maximum aluminum, 0.6 wt. % maximum titanium, 0.001-0.05 wt. % carbon, 0.001-0.035 wt. % nitrogen, 0.001-0.3 wt. % silicon, 1.0 wt. % maximum niobium, 2.5 wt. % maximum iron, 0.5 wt. % maximum manganese, 0.015 wt. % maximum phosphorous, 0.015 wt. % maximum sulfur, 1.0 wt. % maximum cobalt, and the balance nickel and may have a solidus temperature greater than 1312° C.