Stainless Steel Sheet Processing to Suppress Carbide Stripe Patterns
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Solution Overview
Problem
Stainless steel sheets with high hardness and good surface quality are needed for edged tools and precision tools, but existing compositions like 14 mass % Cr-0.5 mass % C steel exhibit stripe patterns during polishing, leading to increased manufacturing costs and reduced yield rates.
Innovation Solution
Adjust the chemical composition to include specific ranges of C, Cr, and control manufacturing conditions such as heating, hot rolling, and coiling temperatures to suppress the formation of coarse Cr-based carbides, thereby preventing stripe patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If 14 mass % Cr-0.5 mass % C steel is used to achieve high hardness, then hardness is improved, but stripe patterns occur during polishing
Solution Approach 1:
The invention changes the chemical composition parameters by limiting C content to 0.30-0.60 mass % and Cr content to 13.0-16.0 mass %, and controls processing parameters (heating temperature 1150-1350°C, holding time 30-180 minutes, cooling rate 1-100°C/s) to prevent coarse carbide formation while achieving high hardness, thereby eliminating stripe patterns during polishing
Solution Approach 2:
The invention performs preliminary controlled cooling at 1-100°C/s after heating and holding to suppress carbide precipitation before subsequent hot rolling, preventing the formation of coarse carbides that would cause stripe patterns during later polishing operations
2Manufacturing precision
If additional polishing process is added to remove stripe patterns, then surface quality is improved, but manufacturing cost increases
Solution Approach 1:
The invention applies preliminary anti-action by controlling the steel composition and processing parameters to prevent stripe pattern formation in the first place, thereby eliminating the need for additional corrective polishing processes and reducing manufacturing costs
3Manufacturing precision
If heavy polishing is applied to remove significant stripe patterns, then surface quality is improved, but productivity decreases
Solution Approach 1:
The invention prevents stripe pattern formation through controlled composition and processing parameters, eliminating the need for time-consuming heavy polishing operations and maintaining high productivity
4Strength
If C content is increased to achieve high hardness, then hardness is improved, but coarse Cr-based carbides form causing stripe patterns
Solution Approach 1:
The invention optimizes the C content range to 0.30-0.60 mass % (avoiding excessive carbon that would form coarse carbides) and combines it with controlled Cr content (13.0-16.0 mass %) and specific cooling rates (1-100°C/s) to achieve high hardness while preventing coarse carbide formation and stripe patterns
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 results in a stainless steel sheet with high hardness and improved surface quality, reducing manufacturing costs and increasing productivity by minimizing stripe patterns.
Implementation Method 1
hold the steel slab at 1200° C. or higher and 1350° C. or lower for 30 minutes or more, thereby dissolving Cr-based carbides into an austenite phase
Implementation Method 2
subject the steel sheet to quenching treatment or quenching and tempering treatments to transform a main phase into a martensite phase
Data Source
AI summary
A method of manufacturing a stainless steel is provided. The stainless steel contains C, Si, Mn, P, S, Cr, Ni, and N in predetermined amounts. A total volume fraction of Cr-based carbides with a grain size of 2.0 μm or more is ≤10%. A steel slab is held at 1200° C.-1350° C. for at least 30 minutes and then hot rolled to obtain a hot-rolled steel sheet. The hot-rolled steel sheet is coiled, where at least three rolling passes with a finish temperature of ≥1050° C. and a rolling reduction of ≥20% are performed, and a coiling temperature of the hot-rolled steel sheet is ≥600° C. The hot-rolled steel sheet is subjected to hot-rolled sheet annealing to obtain a hot-rolled and annealed steel sheet, where a holding temperature is 750° C.-900° C. and a holding time is ≥10 minutes.