Diffusion Layer Coating for Tubular Gripping Components

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Solution Overview

Problem

Conventional gripping tools for corrosion-resistant alloy (CRA) tubulars face difficulties in penetrating the hard outer layer, leading to slippage and damage, and may transfer ferrous materials, causing corrosion.

Innovation Solution

The use of surface processing methods involving diffusion layers, such as carburizing, boronizing, and chromizing, to enhance the gripping tool's hardness and reduce slippage, while preventing ferrous material transfer, along with toothed gripping surfaces for uniform contact and improved wear resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional gripping tools are used on CRA tubulars, then the tool structure remains simple and cost-effective, but the tool cannot penetrate the hard outer layer, causing slippage and damage

Engineering Contradiction:
Improvegripping capabilityVSAvoidsurface treatment complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The gripping tool undergoes preliminary surface treatment (carburizing, boronizing, chromizing) before use to enhance its gripping capability. This pre-treatment creates a hard outer layer that can effectively penetrate and grip the hard outer layer of CRA tubulars, preventing slippage and damage during operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The surface properties of the gripping tool are fundamentally changed through diffusion-based surface treatments. These processes alter the chemical composition and microstructure of the tool's surface, creating a hardened layer with significantly improved mechanical properties (higher hardness and wear resistance) while maintaining the ductility of the base material.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If conventional gripping tools are used, then manufacturing cost is low, but ferrous material transfer occurs causing corrosion of CRA tubulars

Engineering Contradiction:
Improvecorrosion preventionVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

A non-ferrous diffusion layer (containing boron, chromium, or carbon) is created on the gripping tool surface to act as an intermediary barrier. This layer prevents direct contact between ferrous base material and the CRA tubular, eliminating galvanic corrosion while still providing effective gripping through its hard, wear-resistant properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The gripping tool becomes a composite structure with a ductile ferrous base material and a hard non-ferrous surface layer. This composite construction combines the advantages of both materials: the base provides toughness and ductility, while the surface layer provides corrosion resistance and gripping hardness.

Inventive Principle:
Principle #40Composite materials

3Strength

If the gripping tool surface is hardened to increase hardness, then gripping performance improves, but the tool may become too brittle and lose ductility

Engineering Contradiction:
Improvesurface hardnessVSAvoidductility retention
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The gripping tool exhibits local quality differentiation: the surface layer is hardened to high hardness for effective gripping, while the base material remains ductile for overall structural integrity. This gradient in material properties is achieved through controlled diffusion processes that create a transition zone between the hard surface and softer core.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The surface hardening is performed as a preliminary treatment before the tool enters service. This allows the hard layer to be established while the base material retains its ductility, creating a tool that can withstand both the high stresses of gripping hard CRA tubulars and the impact loads encountered during operation.

Inventive Principle:
Principle #10Preliminary action

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 treated gripping tools effectively penetrate and grip CRA tubulars with reduced slippage and corrosion risk, maintaining ductility and preventing ferrous material transfer, resulting in enhanced gripping performance and longer lifespan.

Implementation Method 1

surface processing methods involving diffusion layers, such as carburizing, boronizing, and chromizing

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

surface processing methods involving diffusion layers, such as carburizing, boronizing, and chromizing

Methodology Applied
Scientific EffectCarburizing: Carburizing

Implementation Method 3

surface processing methods involving diffusion layers, such as carburizing, boronizing, and chromizing

Methodology Applied
Scientific EffectBoronizing:

Implementation Method 4

surface processing methods involving diffusion layers, such as carburizing, boronizing, and chromizing

Methodology Applied
Scientific EffectChromizing:

Implementation Method 5

The outer layer may be heat treated to achieve the desired hardness and mechanical properties

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentEP3192893B1Coating system for tubular gripping components
Publication Date: 2023.11.15 FRANKS INT
  • EP3192893B1 patent drawingFigure 1
  • EP3192893B1 patent drawingFigure 2A~2B
  • EP3192893B1 patent drawingFigure 3A~3B

AI summary

A gripping tool includes a gripping element and at least one gripping surface formed on the gripping element. The at least one gripping surface includes a plurality of teeth extending from the gripping element an outer layer. A method to surface process a gripping surface of a gripping tool includes providing the gripping surface in an environment comprising a source of additive material and heating the gripping surface at a temperature and a time to diffuse the additive material a depth into the gripping surface to form a diffusion layer.