Altin-Crn Multilayer Coating for Forming Tool Wear Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current coatings for forming tools used in high-strength steel and aluminum forming operations suffer from limited tool life due to abrasive and adhesive wear, leading to frequent tool changes and productivity losses, especially when dealing with Advanced High Strength Steels (AHSS) and aluminum alloys, and existing solutions using hydrocarbon gases pose contamination risks in PVD coating processes.
Innovation Solution
A multilayer coating comprising a CrN base layer and an AlTiN/CrN multilayer structure with specific thickness and composition ratios, deposited using physical vapor deposition techniques, providing enhanced wear resistance and fatigue resistance without the use of hydrocarbon gases, and optionally combined with a nitriding pre-treatment for improved adhesion and hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coatings (CrN, AlCrN, TiCrN, TiN, TiCN, TiAlN) are applied on forming tools, then wear resistance is improved, but tool life remains limited due to abrasive and adhesive wear when forming high-strength steels
Solution Approach 1:
The patent applies a composite multilayer coating structure consisting of alternating CrN and AlTiN layers. The CrN layers provide wear resistance while the AlTiN layers provide oxidation resistance and ductility. This composite structure synergistically combines the advantages of different materials to simultaneously improve wear resistance and extend tool life when forming high-strength steels.
Solution Approach 2:
The coating is segmented into multiple thin alternating layers of CrN and AlTiN, each with specific thicknesses (CrN: 5-20 nm, AlTiN: 10-30 nm). This segmentation creates a nanolayered structure that prevents crack propagation and distributes stress, thereby improving both wear resistance and tool life compared to conventional single-layer or thick-multilayer coatings.
2Ease of manufacture
If hydrocarbon process gases are used in PVD coating processes, then coating deposition is achieved, but contamination of the PVD coating apparatus interior occurs
Solution Approach 1:
The patent extracts and eliminates hydrocarbon process gases from the PVD coating process. Instead, it uses reactive sputtering with nitrogen-containing gases to deposit the CrN and AlTiN layers. This removal of hydrocarbon gases prevents contamination of the PVD apparatus interior while still achieving high-quality coating deposition.
Solution Approach 2:
The patent replaces the chemical vapor deposition mechanism (using hydrocarbon gases) with a physical vapor deposition mechanism (reactive sputtering). This substitution uses physical processes to deposit the coating materials, eliminating the need for hydrocarbon gases and their associated contamination problems.
3Productivity
If forming tools are used for cold forming of Advanced High Strength Steels (AHSS), then light-weight design is enabled, but frequent tool changes are required due to strong abrasive and adhesive wear
Solution Approach 1:
The composite CrN/AlTiN multilayer coating provides superior resistance to both abrasive and adhesive wear when forming AHSS. The CrN layers resist abrasion while the AlTiN layers reduce adhesion, allowing tools to maintain performance for longer periods and reducing production interruptions.
Solution Approach 2:
The coating is applied as a preliminary protective layer on the forming tool surfaces before tool manufacturing is completed. This pre-applied protective layer prevents wear during the tool's service life, enabling the tool to maintain its light-weight design capability without requiring frequent replacements.
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 coating significantly increases the tool life of forming tools by providing superior wear resistance and fatigue resistance, reducing the need for frequent tool changes and maintaining surface properties without additional layers, thus enhancing productivity and reducing contamination risks in PVD processes.
Implementation Method 1
deposited using physical vapor deposition techniques
Implementation Method 2
optionally combined with a nitriding pre-treatment for improved adhesion and hardness
Data Source
AI summary
The present invention relates to a coating for forming tools to be used in a forming operation of a workpiece material, wherein the coating is deposited on a substrate surface and the coating comprises a lower layer (10) and an upper layer (20), wherein the lower layer (10) is deposited closer to the substrate surface than the upper layer (20), wherein the lower layer (10) mainly comprises chromium nitride, and the upper layer (20) is deposited as multilayer formed by a plurality of A-layers (22) and B-layers (21) deposited alternate one on each other forming a sequence of . . . /A/B/A/B/A/B/ . . . -layers (22,21), wherein the A-layers (22) mainly comprise aluminum titanium nitride, and the B-layers (21) mainly comprise chromium nitride.