Large Crank Throw Forging with Two-Heating Progressive Forming
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Solution Overview
Problem
Conventional forging methods for large crank throws are inefficient, costly, and result in low yield, poor structural quality, and high material consumption due to complex processes, unreasonable die configurations, and unscientific die changes.
Innovation Solution
A two-heating forming forging process using a semi-die forging method with multiple anvil dies and manipulators to progressively form a crank throw preform through first and second heating stages, involving upsetting, stretching, and bending processes to achieve precise journal formation in one heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional die forging method is used with high-pressure forging machine (10000 tons or above) and expensive die, then the crank throw can be forged, but the production cost is high and production efficiency is low
Solution Approach 1:
The forging process is divided into two separate heating stages: first heating for forming the double-wing body preform, and second heating for forming the journal portion. This segmentation allows each stage to focus on specific geometric features, reducing overall process complexity and improving efficiency while maintaining product strength
Solution Approach 2:
The first heating stage performs preliminary forming of the double-wing body preform with optimized geometry. This preliminary action prepares the workpiece for the second heating stage, reducing the complexity of the final forging operation and enabling the use of lower-pressure equipment
2Strength
If conventional die forging method is used, then the crank throw can be forged, but the forging piece yield is low and fails to meet forging ratio
Solution Approach 1:
The invention optimizes the forging ratio parameters for both heating stages. The first heating stage uses a forging ratio of 2.5-3.5, and the second heating stage uses a forging ratio of 1.5-2.5. These optimized parameters ensure adequate plastic deformation to refine the grain structure and eliminate defects while minimizing material loss and achieving high yield
3Shape
If bending forging method is used, then the metal flow direction is good and forming is easy, but the heating number is large (5-7 times) which increases material consumption and energy consumption
Solution Approach 1:
The invention merges multiple forging operations into just two heating stages. The first heating combines preform creation with double-wing body formation, and the second heating combines journal formation with final shaping. This merging reduces the heating number from 5-7 times to just 2 times, significantly reducing energy consumption while maintaining good forming quality
Solution Approach 2:
Each heating stage is designed with specific local quality objectives: the first heating focuses on creating the double-wing body preform with optimized geometry, while the second heating focuses on forming the journal portion with precise dimensions. This localized approach ensures optimal metal flow and forming quality for each specific feature
4Strength
If conventional forging process with repeated change of anvil dies is used, then the crank throw can be forged, but the process is complex and time-consuming
Solution Approach 1:
The forging process is segmented into two distinct heating stages, each with specific forming objectives. This segmentation eliminates the need for repeated anvil die changes within a single heating cycle, reducing process complexity while ensuring adequate strength through controlled deformation at each stage
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 process enhances forging efficiency, reduces material loss, lowers production costs, and improves structural quality by minimizing cold working and using a low-pressure forging machine to complete the forging in fewer steps.
Implementation Method 1
heating the steel billet to a set forging temperature
Implementation Method 2
placing the steel billet heated in step 1 between the upper anvil and the small flat anvil, to stretch (draw out) the steel billet
Implementation Method 3
upsetting the forging piece to 1/2 of its original length
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A two-fire forming forging process for a large crank throw, comprising a forging machine, an anvil die, and an operation device. The process comprises: setting the shape and parameters of a precast forging piece having a boss and two wings in a first fire, and using multiple upsetting and stretching processes to complete preform forging; setting the shape and parameters of a multi-step transition piece in a second fire, changing an angle for flipping back and forth and moving left and right for forging and pressing and repeatedly changing the anvil die for forging and pressing, rolling, pressing, and bending by using a reverse buckling bending die provided with an arc-shaped pressing face, pressing for multiple times by using a plurality of mandrels to realize progressive transition forming of the forging piece, so as to complete crank throw forming forging. According to the process, forming forging and bending forging of a crank throw forging piece are completed by using low pressure and a short forging stroke, so that a forging machine having low pressure completes a process of forging a large crank throw forging piece, and the process has the characteristics of a large forging ratio, a good forming degree, a short forging time, low material losses, and low production costs.