Ni-Based Hot Forging Die Coating for Oxidation Resistance
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Solution Overview
Problem
Ni-based superalloy hot forging dies face issues with oxidation and scale scattering during high-temperature use, leading to deteriorations in working environment and die shape, which reduces their oxidation resistance over time.
Innovation Solution
A hot forging die with a Ni-based superalloy composition of 10.3 to 11.0% W, 9.0 to 11.0% Mo, and 5.8 to 6.8% Al, coated with an inorganic material layer containing 30% or more of Si, Cr, and Al, forming a nitride, oxide, or carbide layer to prevent oxidation and scale scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a Ni-based superalloy is used as a hot forging die to achieve high-temperature compressive strength, then the die can withstand hot forging at 1000°C or more, but the die surface oxidizes and fine scales scatter during cooling, deteriorating working environment and die shape
Solution Approach 1:
The patent applies a coating layer comprising Cr-rich nitride and Cr-rich oxide phases on the Ni-based superalloy die surface. This composite structure combines the high-temperature strength of the Ni-based superalloy base material with the oxidation resistance of the Cr-rich coating layer, resolving the contradiction between strength and oxidation resistance
Solution Approach 2:
The patent controls the Al content within a specific range (5.8-6.8%) to optimize the balance between high-temperature strength and oxidation resistance. By precisely adjusting compositional parameters, the die achieves both required mechanical strength and improved surface oxidation behavior
2Object-affected harmful factors
If the Al content in the Ni-based superalloy is increased to improve oxidation resistance, then the die surface is better protected, but the high-temperature compressive strength may be compromised
Solution Approach 1:
The patent optimizes the Al content within a specific range (5.8-6.8%) to achieve the best balance between oxidation resistance and high-temperature strength. This precise parameter control ensures that sufficient Al is present for oxidation protection while maintaining the required mechanical properties
Solution Approach 2:
The formation of a composite coating layer with Cr-rich nitride and Cr-rich oxide phases provides enhanced oxidation resistance without relying solely on high Al content in the base material, thus preserving the high-temperature strength of the Ni-based superalloy
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 coated die exhibits high oxidation resistance, preventing surface oxidation and scale scattering, even after repeated use, thus maintaining effective performance in high-temperature environments and minimizing environmental and shape-related deteriorations.
Implementation Method 1
a coating layer of inorganic material that is formed on at least one of a forming surface and a side surface of the die and contains 30 mass % or more in total of one or more of Si, Cr, and Al out of Si and metal elements
Data Source
AI summary
To provide a hot forging die made of a Ni-based superalloy, which is free from any deteriorations in working environment and die shape during hot forging in the air, and also provide a manufacturing process for a forged product using the same and a manufacturing process for a hot forging die. The hot forging die includes: a base body made of a Ni-based superalloy consisting of, by mass, 10.3 to 11.0% of W, 9.0 to 11.0% of Mo, and 5.8 to 6.8% of Al and balance of Ni with inevitable impurities; and a coating layer of inorganic material that is formed on at least one of a forming surface and a side surface of the die and contains 30 mass % or more in total of one or more of Si, Cr, and Al out of Si and metal elements.