Steel Blank Edge Heat Treatment for Crack-Resistant Forming
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Solution Overview
Problem
High Strength Steels (HSS) are prone to crack formation during forming due to the high hardness gradient and internal stresses induced by the cutting process, which complicates their formability and requires costly post-treatment methods like mechanical brushing.
Innovation Solution
A method involving heat treatment of the steel blank by directing thermal energy to the peripheral thickness, creating a heat-treated zone that relieves internal stresses and modifies the microstructure to increase ductility and reduce crack sensitivity, without melting the steel and minimizing coating evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat treatment is performed on the surface of steel blanks using conventional methods, then the formability is improved, but the productivity is low and the coating evaporates significantly
Solution Approach 1:
The patent replaces conventional surface heat treatment methods with edge heat treatment using a laser beam. Instead of heating the entire surface, the laser beam is directed specifically at the edges of the steel blank, substituting a general mechanical heating process with a more precise energy delivery method that improves productivity while maintaining formability benefits
Solution Approach 2:
The patent applies heat treatment locally only to the edges of the steel blank rather than the entire surface. The laser beam is configured to heat only the peripheral regions where crack formation is most likely to occur during forming, preserving the metallic coating on the main surface while improving formability at critical locations
2Reliability
If heat treatment is performed on the surface of steel blanks, then the formability is improved, but the coating thickness decreases significantly
Solution Approach 1:
The patent applies heat treatment locally only to the edges of the steel blank rather than the entire surface. The laser beam is configured to heat only the peripheral regions where crack formation is most likely to occur during forming, preserving the metallic coating on the main surface while improving formability at critical locations
Solution Approach 2:
The patent replaces conventional surface heat treatment methods with edge heat treatment using a laser beam. Instead of heating the entire surface, the laser beam is directed specifically at the edges of the steel blank, substituting a general mechanical heating process with a more precise energy delivery method that improves productivity while maintaining formability benefits
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 method significantly improves the formability of HSS by reducing crack formation sensitivity, maintaining the structural integrity of the part, and allowing for efficient processing of coated blanks with minimal coating loss, while also offering high productivity and versatility.
Implementation Method 1
a heat-treatment operation is performed on the steel blank (1) by directing a thermal energy Q provided by at least one heat source (16) on at least part of a peripheral thickness (6) of said steel blank (1)
Implementation Method 2
the temperature of said heat-treated volume (22) is comprised within the range of 400° C. to 1500° C., wherein the entire volume of the steel blank (1) stays solid during the heat-treatment operation
Data Source
AI summary
A method to improve the formability of steel blanks, for steels containing at least 5% martensite, and possibly some ferrite, bainite and residual austenite and having an ultimate tensile strength of at least 500 MPa and possibly having a metallic coating layer on at least one side, wherein the steel blank is heat-treated on at least part of its peripheral thickness using at least one heat source, which heats the steel in a heat-treated zone to a temperature between 400° C. and 1500° C. without melting the steel in any points of the heat-treated zone.