Forging Die Surface Lubrication for High Frictional Heat
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Solution Overview
Problem
Existing methods for improving die durability in warm or hot forging, such as those using high-speed tool steels and surface treatments, are insufficient for complex shapes and high frictional heat conditions, leading to a need for enhanced durability and heat management.
Innovation Solution
A method involving a die made of 'matrix high-speed steel' with a nitrided or nitrosulfidized layer and a water-soluble polymer lubricant containing 0.01 to 0.98 mass% sulfate, applied to the working surface preheated to 150 to 400°C, to optimize surface treatment and reduce frictional heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high-speed tool steels and surface treatments are used for dies, then basic durability is improved, but durability is insufficient under complex shapes and high frictional heat conditions
Solution Approach 1:
The die employs a composite structure combining matrix high-speed steel base material with a nitrided or nitrosulfidized surface layer. This composite material approach allows the base material to provide toughness and strength while the surface layer provides enhanced wear resistance and reduced friction, specifically addressing the durability issue under high frictional heat conditions through the synergistic combination of different material properties.
Solution Approach 2:
The invention applies parameter changes by using a water-soluble polymer lubricant containing 0.01 to 0.98 mass% sulfate, which modifies the friction and heat generation parameters during forging. The lubricant parameters are optimized to reduce frictional heat under the specific working conditions of complex shape forging, thereby improving die durability without compromising the forging quality.
2Shape
If larger loads are exerted on working surfaces during forging of complex shapes, then near net shapes with complex geometry are achieved, but frictional heat increases and durability decreases
Solution Approach 1:
A water-soluble polymer lubricant containing sulfate acts as an intermediary substance between the die working surface and the workpiece. This lubricant mediator reduces direct metal-to-metal contact, thereby reducing frictional heat generation during the forging of complex shapes. The lubricant film allows for larger loads to be applied without proportionally increasing the temperature rise, enabling complex near net shape forging while maintaining die durability.
3Strength
If matrix high-speed steel with optimized composition is used, then base strength and toughness are improved, but surface layer compatibility and optimal performance require specific lubricant combinations
Solution Approach 1:
The die structure implements local quality by having different regions with different properties: the base material uses matrix high-speed steel with optimized composition (C: 0.4-0.7%, Cr: 4.0-6.0%, Mo: 2.0-4.0%, V: 0.5-2.5%) for overall strength and toughness, while the surface layer uses nitrided or nitrosulfidized treatment for localized wear resistance. This local differentiation allows each region to be optimized for its specific function, managing the complexity through functional specialization.
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 approach significantly enhances the durability of the die by forming a magnetite layer with excellent lubricity, reducing frictional heat and extending the die's lifespan by up to twice that of conventional methods.
Implementation Method 1
a nitrided layer or a nitrosulfidized layer on the working surface thereof
Implementation Method 2
it is effective to perform various types of surface treatments on the working surface thereof... A typical example of these surface treatments is a nitriding treatment
Implementation Method 3
spraying or applying a water-soluble polymer lubricant containing 0.01 to 0.98 mass% of a water-soluble sulfate onto a working surface of the die... in order to suppress the above-described increase in frictional heat
Implementation Method 4
forming a magnetite layer with excellent lubricity... by using various nitrogen/sulfur supply sources as treatment mediums
Data Source
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AI summary
A method for manufacturing a forged article, capable of improving the durability of a die for forging is provided. The method, includes forging a steel material, by using a die, by spraying or applying a water-soluble polymer lubricant containing 0.01 to 0.98 mass% of a water-soluble sulfate onto a working surface of the die, the die being made of a raw material having a constituent composition of, by mass%, 0.4 to 0.7% of C, 1.0% or less of Si, 1.0% or less of Mn, 4.0 to 6.0% of Cr, 2.0 to 4.0% of (Mo+1/2W), 0.5 to 2.5% of (V+Nb), 0 to 1.0% of Ni, 0 to 5.0% of Co, 0.02% or less of N, and a remnant composed of Fe and impurities, and having hardness of 55 to 60 HRC, and the die including a nitrided layer or a nitrosulfidized layer on the working surface thereof.