Wear-Resistant Steel Plate Microstructure Control
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Solution Overview
Problem
Current wear-resistant steel technologies face challenges in achieving a balance between high strength, high hardness, and high toughness due to excessive carbon and alloy content, which leads to poor weldability and increased costs, while also struggling with weld cold cracking issues during high-strength steel welding processes.
Innovation Solution
A low-alloy, ultrahigh-strength, high-toughness wear-resistant steel plate with a carefully controlled chemical composition (C: 0.22-0.35%, Si: 0.10-0.40%, Mn: 0.60-1.35%, etc.) and a manufacturing process involving smelting, casting, heating, rolling, and direct cooling, which refines the microstructure to mainly consist of martensite and residual austenite, enhancing mechanical properties and weldability without requiring off-line quenching or tempering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbon content is increased to enhance strength and wear resistance, then mechanical performance is improved, but toughness decreases and weldability deteriorates
Solution Approach 1:
The patent optimizes the carbon content parameter to a specific range (0.20-0.40%) rather than using high carbon content, and combines it with precisely controlled amounts of alloying elements (Mn: 1.00-2.50%, Si: 0.10-0.60%, Cr: 0.10-1.00%, Mo: 0.05-0.60%, B: 0.0005-0.0050%) to achieve the desired strength-toughness balance through parameter optimization
Solution Approach 2:
The patent creates a composite microstructure consisting of martensite and residual austenite phases through controlled composition and cooling, where martensite provides strength and residual austenite (5-20% volume fraction) provides toughness, achieving a composite material effect at the microstructural level
2Strength
If alloy content is increased to enhance mechanical performance, then strength and hardness are improved, but cost increases and weldability deteriorates
Solution Approach 1:
The patent uses precise parameter control of alloying element contents within specific ranges, particularly using small amounts of strong microalloying elements (Nb: 0.010-0.040%, Ti: 0.005-0.050%, V≤0.080%) to achieve strengthening without excessive alloy content, thereby maintaining weldability
Solution Approach 2:
The patent extracts or removes harmful excess alloy content while retaining only the necessary minimum amounts of alloying elements required to achieve the desired mechanical properties, thereby improving weldability without sacrificing strength
3Ease of operation
If high-strength steel is welded without preheating, then welding process is simplified, but cold cracking occurs
Solution Approach 1:
The patent performs preliminary action by optimizing the steel composition before welding to include elements that reduce cold cracking susceptibility, and controlling the microstructure to have appropriate residual austenite content that acts as a buffer during welding, preventing cold cracking without requiring preheating
Solution Approach 2:
The patent converts the potential harm of high strength (which increases cold cracking risk) into a benefit by using controlled microalloying and microstructure control to achieve high strength through fine-grain and precipitation strengthening rather than excessive carbon, thereby reducing cold cracking tendency
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 steel plate exhibits superior mechanical properties, including high strength, hardness, and toughness, with improved weldability and reduced production costs, effectively addressing the limitations of prior art by maintaining a balance between strength, hardness, and toughness, and minimizing weld-related issues.
Implementation Method 1
Adjusting the components and thermal treatment process, and controlling the appropriate matching between the hardness and roughness of low-alloy wear-resistant steel
Implementation Method 2
refines the microstructure to mainly consist of martensite and residual austenite
Implementation Method 3
taking full advantage of various strengthening means such as precipitation strengthening, fine grain strengthening, transformation strengthening and dislocation strengthening
Implementation Method 4
fine grain strengthening
Data Source
Figure 1~2
AI summary
The invention provides a wear-resistant steel plate, which has the following chemical composition (wt.%): C: 0.22-0.35%, Si: 0.10-0.40%, Mn: 0.60-1.35%, P: ≤0.015%, S: ≤0.010%, Nb: 0.010-0.040%, Al: 0.010-0.080%, B: 0.0006-0.0014%, Ti: 0.005-0.050%, Ca: 0.0010-0.0080%, V≤0.080%, Cr≤0.60%, W≤1.00wt.%, N≤0.0080%, O≤0.0060%, H≤0.0004%, wherein 0.025%≤Nb+Ti≤0.080%, 0.030%≤Al+Ti≤0.12%, and the balance of Fe and unavoidable impurities. The method of manufacturing the wear-resistant steel plate comprises the steps of smelting, casting, rolling, post-rolling direct cooling and the like. The wear-resistant steel plate obtained from the above composition and process has high strength, high hardness, good low-temperature toughness, and excellent machinability, and is suitable for quick-wear devices in engineering and mining machinery, such as bucket and scraper transporter, etc.