Stacked Continuous Casting Billets for Homogenized Forgings
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Solution Overview
Problem
Current methods for producing high-quality forgings face challenges such as microscopic shrinkage cavities, porosities, and macroscopic segregation in continuous casting billets, leading to inconsistent mechanical properties and reduced utilization rates, while traditional forging methods are inefficient and prone to interface oxidation.
Innovation Solution
A constructing-and-forging method involving surface machining and plasma cleaning of continuous casting billets, followed by vacuum electron beam welding and multidirectional forging with pressure and temperature dwelling to achieve complete interface welding and homogenization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous casting billets with large dimensions are used, then production efficiency and cost effectiveness are improved, but shrinkage cavities and porosities occur in the center of the billet
Solution Approach 1:
The continuous casting billet is divided into multiple smaller billets through cutting, and these segmented billets are then stacked and forged together. This segmentation allows the use of smaller billets that avoid shrinkage cavities while achieving the desired large final dimensions, resolving the contradiction between production efficiency and billet quality.
Solution Approach 2:
Multiple billets are combined through stacking and forging to create a composite structure that achieves the desired large dimensions without the defects associated with single large billets. The composite approach allows each component billet to maintain high quality while the assembled structure meets production requirements.
2Reliability
If head and tail of ingots are cut off to reduce defects, then mechanical property consistency is improved, but material utilization rate deteriorates
Solution Approach 1:
Instead of cutting off defective portions from single large ingots, the approach is inverted: multiple smaller billets without defects are stacked and forged together. This inversion eliminates the need to remove material while achieving uniform mechanical properties throughout the final product.
Solution Approach 2:
The method recovers what would otherwise be wasted material (the head and tail portions) by using multiple complete billets of optimal dimensions. Each billet is used fully without cutting losses, and the stacking process recovers the structural integrity that would be lost in traditional single-ingot approaches.
3Object-affected harmful factors
If vacuum electron beam welding is used to seal billet interfaces, then interface oxidation is prevented, but welding completeness and homogeneity with billet body deteriorate
Solution Approach 1:
The billets are preheated to forging temperature before the welding operation. This preliminary heating ensures that the material is at optimal temperature for welding, promoting complete fusion and homogeneous interface structure while maintaining the vacuum protection against oxidation.
Solution Approach 2:
The welding process utilizes controlled changes in temperature and pressure parameters. By applying sufficient pressure and maintaining optimal temperature during the welding operation, complete interface fusion is achieved, making the welded interfaces homogeneous with the billet body while preserving the oxidation-free environment.
4Productivity
If rolling process is used for cladding, then heavy gauge plate production is enabled, but interface welding completeness deteriorates due to short pressure duration
Solution Approach 1:
The rolling process is replaced with a forging process that applies sustained pressure and heat. This substitution allows for complete interface welding through prolonged pressure application and thermal diffusion, achieving homogeneous interfaces that cannot be obtained through rapid rolling operations.
Solution Approach 2:
The billets are preheated to high temperature before welding, which promotes diffusion and completes the welding process. This preliminary heating action compensates for the relatively short duration of the welding operation itself, ensuring complete interface fusion and homogeneity.
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
This method enables the production of homogenized forgings with improved mechanical properties and reduced manufacturing costs, increasing material utilization and reducing environmental impact by eliminating interface defects and oxidation.
Implementation Method 1
the interfaces between the plates are sealed around by electron beam welding
Implementation Method 2
Vacuum electron beam welding is used to protect the interface from severe pollution and high temperature oxidation
Implementation Method 3
performing vacuum plasma cleaning operation to the surfaces to be welded
Implementation Method 4
heating the preformed billets to a certain temperature in a heating furnace
Implementation Method 5
forging the preformed billets by a hydraulic press
Implementation Method 6
using pressure dwelling and temperature dwelling means during a first upsetting process to weld the surfaces completely together
Implementation Method 7
Metal is diffusion welded under high temperature during cladding rolling process
Data Source
AI summary
A constructing-and-forging method for preparing homogenized forged pieces comprises: preparing preformed billets: cutting off a plurality of continuous casting billets, milling and smoothing surfaces of the billets to be welded, performing vacuum plasma cleaning operation to the surfaces to be welded, stacking the plurality of billets and sealing around the surfaces in a vacuum chamber by electron beam welding; forge-welding and homogenizing the preformed billets: heating the preformed billets to a certain temperature in a heating furnace and taking the heated preformed billets out of the heating furnace, forging the preformed billets by a hydraulic press, then using three-dimensional forging to disperse the welded surfaces such that composition, structure and inclusion of the interface areas are at the same level as those of the bodies of the billets. Cheap continuous casting billets are stacked and forge welded.