Alloy Ingot Outer Shell Reduces Surface Cracking
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Solution Overview
Problem
Alloy ingots, particularly those made from crack-sensitive materials like nickel base, iron base, and cobalt base alloys, tend to experience surface cracking during hot working operations due to thermal gradients, leading to reduced production yields and the need for costly re-canning and defect monitoring.
Innovation Solution
A process involving vacuum arc remelting where an alloy electrode is remelted into an alloy liner within a crucible, forming an ingot with an outer ductile layer metallurgically bonded to a crack-sensitive inner core, reducing surface cracking by insulating and mechanically protecting the ingot during hot working.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alloy ingots are made from crack-sensitive materials like nickel base, iron base, and cobalt base alloys, then the desired alloy composition and properties are achieved, but surface cracking occurs during hot working operations due to thermal gradients
Solution Approach 1:
The ingot is segmented into two distinct zones: an inner core made from crack-sensitive alloy material and an outer shell made from a more ductile alloy. This segmentation allows each zone to serve its specific function - the core provides the desired alloy properties while the shell prevents surface cracking during hot working operations.
Solution Approach 2:
The invention creates a composite ingot structure combining two different alloy materials with complementary properties. The inner core uses the crack-sensitive alloy (e.g., nickel base, iron base, or cobalt base alloy) to achieve desired composition and properties, while the outer shell uses a more ductile alloy to prevent surface cracking, resulting in a composite material system that overcomes the limitations of either material alone.
2Ease of manufacture
If traditional single-material ingots are used, then the manufacturing process is simple, but costly re-canning and defect monitoring are required during hot working
Solution Approach 1:
The protective outer shell is applied during the ingot formation stage (vacuum arc remelting) rather than adding protective measures during hot working. This preliminary action of creating a crack-resistant shell before hot working eliminates the need for re-canning and defect monitoring during subsequent processing operations.
3Reliability
If an outer layer is added to protect the inner core, then surface cracking is reduced, but the device complexity increases
Solution Approach 1:
The protective shell and the structural core are merged into a single integrated ingot structure through metallurgical bonding during vacuum arc remelting. This combining of functions (protection and structure) into one unified component achieves surface cracking resistance without requiring separate protective devices or complex assembly processes.
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 process significantly reduces surface cracking of alloy ingots during hot working, improving production yields and allowing for easier monitoring of defects without the need for re-canning, while maintaining the chemical integrity of the inner ingot core.
Implementation Method 1
An alloy electrode is remelted in the vacuum arc remelting apparatus. The alloy electrode is vacuum arc remelted into the alloy liner in the crucible.
Implementation Method 2
The outer layer comprises an alloy that is more ductile than the alloy comprising the inner ingot core. The outer layer reduces an incidence of surface cracking of the alloy ingot during the application of force to the alloy ingot.
Data Source
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AI summary
Processes and methods related to producing, processing, and hot working alloy ingots are disclosed. An alloy ingot is formed including an inner ingot core and an outer layer metallurgically bonded to the inner ingot core. The processes and methods are characterized by a reduction in the incidence of surface cracking of the alloy ingot during hot working.