Molybdenum Strip Production via Roll Compaction and Warm Rolling
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Solution Overview
Problem
The conventional process for producing molybdenum-based thin strips is energy-intensive, costly, hazardous, and environmentally unfriendly due to the need for multiple hot rolling, chemical etching, and cleaning operations.
Innovation Solution
A method involving roll compaction to form a 'green' strip, followed by sintering under a hydrogen atmosphere to improve strength and reduce oxygen content, and subsequent thermo-mechanical working through warm rolling and cold rolling at lower temperatures, eliminating the need for hot rolling and chemical etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional hot rolling process is used to produce molybdenum strip, then the material can be processed into thin strips, but the process requires multiple hot rolling, chemical etching, and cleaning operations which are energy-intensive and environmentally harmful
Solution Approach 1:
The invention changes the temperature parameter from conventional hot rolling (above recrystallization temperature, typically 1000-1400°C) to warm rolling (200-500°C). This parameter change eliminates the need for multiple hot rolling passes, chemical etching, and cleaning operations, significantly reducing energy consumption while achieving the same thin strip product
Solution Approach 2:
The invention extracts and eliminates the harmful chemical etching and cleaning steps from the conventional process. By using warm rolling instead of hot rolling, the process removes the need for chemical treatments to remove embedded iron particles and surface oxides, simplifying the manufacturing process and reducing environmental impact
2Manufacturing precision
If multiple hot rolling and chemical etching operations are performed, then the desired strip thickness and purity are achieved, but the process becomes costly and hazardous
Solution Approach 1:
The invention uses an inert or controlled atmosphere during warm rolling to prevent oxidation and contamination of the molybdenum strip. This eliminates the need for chemical etching and cleaning operations that would otherwise be required to remove surface oxides and embedded particles, achieving the desired purity without harmful chemicals
Solution Approach 2:
By changing the rolling temperature to the warm working range (200-500°C), the invention achieves adequate ductility for thin strip production without requiring hot rolling. This temperature parameter change eliminates the formation of significant surface oxides and embedded contaminants, achieving high purity without chemical treatments
3Productivity
If conventional hot rolling process is used, then molybdenum strip can be produced, but the process requires thick slabs (1.0" to 4.0") to be reduced through multiple operations
Solution Approach 1:
The invention performs preliminary consolidation of the molybdenum powder into a green strip at the desired final thickness before sintering. This preliminary action at the correct thickness eliminates the need for subsequent thick-to-thin reduction operations, significantly reducing processing time and improving productivity
Solution Approach 2:
The invention segments the manufacturing process into distinct stages: powder consolidation at target thickness, sintering, and optional warm rolling. This segmentation allows each stage to be optimized independently, with the consolidation stage producing the correct thickness upfront, eliminating multiple reduction passes and chemical treatment steps
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 reduces processing time and energy consumption while achieving mechanical and thermo-physical properties comparable to conventionally processed molybdenum strips, minimizing environmental impact and operational costs.
Implementation Method 1
Following roll compaction, the green strip is sintered under an atmosphere containing hydrogen to improve the strength and reduce the oxygen content of the strip
Implementation Method 2
the green strip is sintered under an atmosphere containing hydrogen to improve the strength and reduce the oxygen content of the strip
Implementation Method 3
The sintered strip is then thermo-mechanically worked (warm rolling). As used herein throughout the specification and the claims, the term 'warm rolling' means heating at least one of the strip and/or work rolls. According to embodiments of the present invention, the warm rolling temperatures are preferably in the 100 °C to 500 °C range
Implementation Method 4
Intermediate re-crystallization or stress relief anneals are carried out between the warm working cycles
Implementation Method 5
The material is subsequently cold rolled. As used herein throughout the specification and the claims, the term 'cold rolling' means mechanically working the strip without adding heat to the strip or work rolls until reaching the final desired finished thickness of the strip
Data Source
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AI summary
A method of making a molybdenum or molybdenum alloy metal strip is disclosed. The method includes roll compacting a molybdenum-based powder into a green strip. The method also includes sintering the green strip followed by a combination of warm rolling, annealing, and cold rolling steps to form the final metal strip which may be cut-to-length. The strip at the final thickness may also undergo a optional stress relief step.