Flake Graphite Cast Iron Cylindrical Member Composition
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Solution Overview
Problem
Cast iron members used for abrasion resistance require improved processability to reduce weight and thickness while maintaining mechanical strength and preventing seizing on sliding surfaces.
Innovation Solution
A cylindrical member made of flake graphite cast iron with a specific composition and structure, including 2.85% to 3.35% C, 1.95% to 2.55% Si, 0.45% to 0.8% Mn, 0.03% to 0.25% P, 0.15% to 0.65% Mo, and 0.15% to 0.65% Ni, with a carbide area ratio of 0.9% to 5.0% in a continuous region, and a flake graphite area ratio of 6.0% to 17.0%, optimized for pearlite or bainite base structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the cast iron member uses conventional compositions and structures for abrasion resistance, then abrasion resistance is improved, but processability deteriorates and seizing resistance is insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition parameters (C: 2.85-3.35%, Si: 1.95-2.55%, Mn: 0.45-0.8%, P: 0.03-0.25%, Cr: 0.15-0.55%, Mo: 0.15-0.65%, Ni: 0.15-0.65%) and structural parameters (carbide area ratio: 0.9-5.0%, flake graphite area ratio: 6.0-17.0%) of the flake graphite cast iron to simultaneously achieve good processability, mechanical strength, abrasion resistance, and seizing resistance, eliminating the need for post-manufacturing heat treatment
Solution Approach 2:
The patent employs composite materials by creating a multi-phase microstructure containing pearlite or bainite as the base structure, dispersed carbides for abrasion resistance, and flake graphite for self-lubrication. This composite structure at the microstructural level provides simultaneous improvement in processability, strength, and resistance to abrasion and seizing
2Weight of moving object
If the cast iron member is reduced in weight and thickness, then weight reduction is achieved, but mechanical strength deteriorates
Solution Approach 1:
The patent uses parameter changes by optimizing the chemical composition (particularly C, Si, Mn, Cr, Mo, Ni content) and microstructural parameters (carbide and graphite area ratios) to achieve high mechanical strength in thinner sections, enabling weight reduction without compromising strength requirements
Solution Approach 2:
The patent applies composite materials through its multi-phase microstructure (pearlite/bainite base with dispersed carbides and flake graphite) that provides high strength-to-weight ratio, allowing the member to be made thinner while maintaining adequate mechanical strength
3Weight of moving object
If the cast iron member is reduced in thickness, then weight reduction is achieved, but productivity is impaired due to processability issues
Solution Approach 1:
The patent applies parameter changes by controlling the chemical composition (C: 2.85-3.35%, Si: 1.95-2.55%, Mn: 0.45-0.8%, P: 0.03-0.25%, S: ≤0.15%, Cr: 0.15-0.55%, Mo: 0.15-0.65%, Ni: 0.15-0.65%) and microstructural parameters to ensure good processability in thinner sections, enabling efficient manufacturing without compromising quality, thus maintaining high productivity
4Ease of manufacture
If conventional flake graphite cast iron compositions are used, then manufacturing cost is reduced, but seizing resistance is insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition parameters (particularly Cr: 0.15-0.55%, Mo: 0.15-0.65%, Ni: 0.15-0.65%, and P: 0.03-0.25%) to enhance seizing resistance through improved microstructural characteristics, while still maintaining cost-effectiveness by using conventional flake graphite cast iron as the base material rather than more expensive alternatives
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 practical processability, excellent mechanical strength, enhanced abrasion resistance, and improved seizing resistance, enabling reduced weight and thickness without compromising performance.
Implementation Method 1
Cast iron members excellent in lubricating action of graphite present in a base have been widely used as members required to have abrasion resistance
Implementation Method 2
members having various compositions, structures, and physical properties have been proposed... excellent in mechanical strength and machinability and can be manufactured easily at low cost
Data Source
Figure 1
Figure 2a~2c
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AI summary
Provided is a cylindrical member made of flake graphite cast iron that has practical processability as well as excellent mechanical strength and further is excellent in abrasion resistance and seizing resistance. Specifically, provided is a cylindrical member made of flake graphite cast iron, the flake graphite cast iron including a composition containing, in terms of mass%, 2.85% or more and 3.35% or less of C, 1.95% or more and 2.55% or less of Si, 0.45% or more and 0.8% or less of Mn, 0.03% or more and 0.25% or less of P, 0.15% or less of S, 0.15% or more and 0.55% or less of Cr, 0.15% or more and 0.65% or less of Mo, 0.15% or more and 0.65% or less of Ni, and the balance of Fe and inevitable impurities.