Ion Nitriding Steel Plunger for Hydraulic Fracturing Pumps
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Solution Overview
Problem
Hydraulic fracturing pump plungers face surface damage and corrosion due to proppant particles and existing protective coatings introduce mechanical and structural issues like adherence deficiencies and stress corrosion cracking, compromising the metallic structure's integrity.
Innovation Solution
A steel plunger treated with an ion nitriding process, combined with a physical vapor deposition (PVD) surface treatment, providing enhanced surface hardness without structural discontinuity or grain size increase, and avoiding the formation of a 'white layer' for improved toughness and hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a protective surface coating is applied via thermal spray to enhance surface hardness, then the surface hardness is improved, but adherence deficiencies and stress corrosion cracking occur compromising the metallic structure integrity
Solution Approach 1:
The patent replaces the mechanical thermal spray coating system with an ion nitriding process that uses ion bombardment and diffusion to embed nitrogen into the steel substrate. This substitution eliminates the need for external coating materials and their associated adherence problems, while achieving surface hardening through controlled nitrogen diffusion and nitride formation within the substrate
Solution Approach 2:
The patent merges the surface hardening function with the substrate material itself by diffusing nitrogen into the steel to form a hardened nitrided layer. This eliminates the separate coating layer and its interface with the substrate, thereby removing the adherence deficiency problem while maintaining surface hardness enhancement
2Object-affected harmful factors
If multiple coating layers are applied to provide protective coverage, then surface protection is improved, but stress corrosion cracking and debonding between layers occur
Solution Approach 1:
The patent extracts and removes the multi-layer coating structure that causes stress corrosion cracking and debonding. Instead, it uses a single ion nitriding process that creates a gradient of nitrogen concentration within the substrate, forming a hardened surface layer without creating interfaces between different coating materials that could crack or debond
Solution Approach 2:
The patent creates a composite structure within the substrate itself through ion nitriding, where nitrogen-diffused regions form a gradient from the surface inward. This internal composite structure provides surface protection without the harmful effects of external multi-layer coatings, as the hardened layer is metallurgically bonded to the substrate
3Strength
If thermal spray coating is applied to the plunger surface, then surface hardness is enhanced, but grain size increases at the interface reducing toughness and hardness
Solution Approach 1:
The patent replaces the thermal spray process with ion nitriding, substituting a mechanical deposition process with a diffusion-based chemical process. This eliminates the thermal cycling and rapid cooling that cause grain growth at the substrate-coating interface, while still achieving surface hardening through nitrogen diffusion and nitride precipitation
4Strength
If HVOF coating process is used to deposit protective material, then surface hardness is improved, but adherence deficiencies allow fluid penetration and corrosion at the interface
Solution Approach 1:
The patent merges the protective function with the substrate by diffusing nitrogen into the steel to form a hardened nitrided layer. This eliminates the separate coating layer and its interface where fluid penetration and corrosion occur, creating a metallurgically bonded hardened surface that prevents fluid ingress
Solution Approach 2:
The patent replaces the mechanical HVOF spray deposition process with ion nitriding that uses ion bombardment and thermal diffusion. This substitution creates a diffusion-bonded nitrogen-enriched layer without the interface discontinuities that allow fluid penetration and corrosion in spray-coated parts
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 ion nitriding and PVD-treated plunger achieves higher surface hardness with metallurgic continuity, reduced roughness, and no adherence deficiencies, enhancing the plunger's durability and performance in hydraulic fracturing operations.
Implementation Method 1
the plunger is a steel plunger treated with an ion nitriding process
Implementation Method 2
ion nitriding process
Implementation Method 3
a physical vapor deposition (PVD) surface treatment
Data Source
AI summary
Steel plungers for hydraulic fracturing pumps having enhanced surface hardness properties, preferably made of alloyed steel and a method for manufacturing said plungers, comprising an ion nitriding process.