Forged Pump Power End Frame to Prevent Weld Fatigue Cracking
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Solution Overview
Problem
Conventional power end frames in hydraulic fracturing pumps suffer from fatigue failure due to welds and castings that are prone to cracking under cyclic stresses, making them poorly suited for severe operating conditions.
Innovation Solution
A one-piece forged crankshaft housing with machined features and bolted-on accessories, eliminating welds and incorporating stayrods to enhance fatigue resistance, while allowing for accurate fatigue analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If welds and castings are used in power end frames, then manufacturing ease is improved, but fatigue resistance deteriorates due to cracking under cyclic stresses
Solution Approach 1:
The power end frame is divided into modular components including a crankshaft housing, crosshead housing, and spacer housing that can be manufactured separately and then assembled together using mechanical fasteners, eliminating the need for welds in fatigue-critical areas
Solution Approach 2:
Multiple housing components are combined into a unified structure through mechanical fastening systems, creating an integrated assembly that achieves the structural benefits of a monolithic design while maintaining the manufacturing and inspection advantages of separable components
2Ease of manufacture
If welds are used to attach accessories, then ease of manufacture is improved, but reliability deteriorates due to crack susceptibility under cyclic loading
Solution Approach 1:
Welding processes are replaced with mechanical fastening systems such as bolts and mechanical connectors to attach accessories to the crankshaft housing, eliminating the creation of weld-induced cracks while maintaining manufacturing efficiency
Solution Approach 2:
The harmful weld joints are extracted from the accessory attachment system, removing the source of fatigue failure while maintaining the functional connection through alternative mechanical means
3Ease of manufacture
If castings are used for the crankshaft housing, then ease of manufacture is improved, but fatigue resistance deteriorates due to porosity and brittleness
Solution Approach 1:
Modern forging processes utilize controlled pressure and temperature conditions to shape the metal, creating a dense, pore-free microstructure that inherently resists fatigue cracking better than traditional castings
Solution Approach 2:
The manufacturing process parameters are changed from casting to forging, fundamentally altering the metal's microstructure and mechanical properties to achieve superior fatigue resistance while maintaining manufacturing feasibility
4Reliability
If a one-piece forged crankshaft housing is used, then fatigue resistance is improved, but device complexity increases due to machining features and bolted accessories
Solution Approach 1:
The crankshaft housing is designed with integrated mounting features and accessory attachment points that are formed as part of the forging process, allowing modular assembly while maintaining structural integrity and reducing overall complexity
Data Source
AI summary
A pump power end frame with a fatigue-resistant crankshaft housing machined from a one-piece forging may include machined features and bolted-on accessories. The crankshaft housing and the accessories have no welds that are subject to cracking in response to cyclic stresses due to operation of the pump.