Cold Work Tool Material Hardness Stability
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Solution Overview
Problem
Cold work tool materials face challenges in maintaining high hardness over a wide range of tempering temperatures due to limitations in tempering temperature adjustments, which affect both hardness and dimensional stability.
Innovation Solution
A cold work tool material with a specific composition and carbide distribution, including C: 0.80% to 2.40%, Cr: 5.0% to 15.0%, Mo and W: 0.50% to 3.00%, V: 0.10% to 1.50%, and Si: not more than 2.00%, along with optional elements, is used to achieve a martensitic structure through quenching and tempering, ensuring a high hardness across a broader tempering temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tempering temperature is adjusted to optimize hardness, then the hardness of the cold work tool is improved, but the dimensional stability and amount of retained austenite are affected
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition parameters (C: 0.80-2.40%, Cr: 5.0-15.0%, Mo+W: 0.50-3.00%, V: 0.10-1.50%) and carbide distribution parameters (proportion of carbides B to A > 80.0%) to achieve optimal hardness while maintaining dimensional stability across a wide tempering temperature range
Solution Approach 2:
The patent creates a composite microstructure consisting of martensite matrix with dispersed carbides (both fine carbides B and coarser carbides A) to achieve synergistic effects where the martensite provides hardness and the carbide distribution provides dimensional stability during tempering
2Adaptability or versatility
If the tempering temperature range is extended to provide flexibility, then the adaptability of the material is improved, but the hardness consistency across the range deteriorates
Solution Approach 1:
The patent changes the composition parameters and carbide distribution to create a material that maintains hardness consistency across an extended tempering temperature range, achieving both adaptability and hardness stability simultaneously
Solution Approach 2:
The patent performs preliminary carbide formation and distribution control during the annealing process before quenching, so that the carbide structure is pre-established to provide dimensional stability during subsequent tempering operations across various temperature ranges
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 solution provides a cold work tool material with high hardness stability over a wide range of tempering temperatures, enhancing both hardness and mechanical properties while maintaining dimensional stability.
Implementation Method 1
the term 'quenching' refers to an operation where a cold work tool material (or a cold work tool material that has been subjected to machining) is heated to an austenitic phase temperature range and then rapidly cooled to transform it into a martensitic structure
Implementation Method 2
The material is machined into a shape of the tool, and thereafter quenched and tempered to adjust its hardness for use
Data Source
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AI summary
The invention provides a cold work tool material which can obtain a high hardness over a wide range of tempering temperatures, and a method of manufacturing a cold work tool with the cold work tool material. The cold work tool material has an annealed structure including carbides, and has a composition including, in mass%, C: 0.80% to 2.40%, Cr: 5.0% to 15.0%, Mo and W contained alone or in combination in an amount of (Mo + 1/2W): 0.50% to 3.00%, and V: 0.10 to 1.50%, and adjusted such that the material has a martensitic structure by quenching. The cold work tool material includes a cross sectional region of an annealed structure, the region having a length of 90 µm and a width of 90 µm and including no carbides having a circle equivalent diameter exceeding 5.0 µm. In the cross sectional region, a proportion of a number of carbides B having a circle equivalent diameter of more than 0.1 µm and not more than 0.4 µm to a number of carbides A having a circle equivalent diameter of exceeds 0.1 µm and not more than 2.0 µm is greater than 80.0%. The method of manufacturing a cold work tool includes a step of quenching and tempering the above cold work tool material.