HDD Boring Bit Hardfacing With Heat-Treated HAZ Control

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Solution Overview

Problem

Current horizontal directional drilling (HDD) components, such as boring bits, face challenges with wear resistance due to issues like heat treatment problems, voids, and poor fusion of welding hard facing materials, leading to softer and harder regions that can be prone to cracking or wear, which affects the durability and lifespan of the bits.

Innovation Solution

The method involves hard facing HDD components using laser cladding or plasma transferred arc (PTA) techniques to create a heat-affected zone (HAZ) that is subsequently removed through heat treatment, resulting in a consistent microstructure and hardness, with a bonding matrix of nickel and tungsten, and embedding carbide inserts through press-fitting to enhance wear resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If weld-on hard facing is applied to enhance wear resistance, then the bit surface becomes harder and more wear-resistant, but the heat from welding creates softer regions in the base material that are prone to cracking and wear

Engineering Contradiction:

Improvewear resistanceVSAvoidcracking resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent converts the harmful heat-affected zone (HAZ) created by welding into a beneficial feature by intentionally creating a softer transition zone that prevents cracking. The HAZ is controlled and managed rather than eliminated, transforming it from a weakness into a stress-relief feature that enhances overall bit reliability during directional drilling operations.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Strength

If weld-on hard facing is applied close to carbide inserts to maximize protection, then wear resistance is improved, but the heat degrades the carbide inserts

Engineering Contradiction:

Improvewear resistanceVSAvoidcarbide insert integrity

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent applies hard facing material selectively in specific zones around carbide inserts rather than uniformly across the entire bit surface. This localized application provides maximum wear protection in high-stress areas while maintaining sufficient clearance from carbide inserts to prevent heat degradation, optimizing both protection and carbide integrity.

Inventive Principle:

Principle #3Local quality

3Strength

If larger carbide inserts are used to enhance bit life, then wear resistance is improved, but the inserts come loose during operation

Engineering Contradiction:

Improvewear resistanceVSAvoidinsert retention

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent creates a composite structure where hard facing material is applied over and around carbide inserts, forming a unified wear-resistant zone. This composite approach combines the hardness of carbide with the protective hard facing layer, securing the inserts in place while maintaining their cutting effectiveness throughout the bit's service life.

Inventive Principle:

Principle #40Composite materials

4Strength

If weld-on hard facing is applied to substantially the entire bit surface to maximize protection, then wear resistance is improved, but the application expense increases considerably

Engineering Contradiction:

Improvewear resistanceVSAvoidhard facing material quantity

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The patent applies hard facing material only in specific high-wear zones such as the leading edge, thrust face, and areas surrounding carbide inserts, rather than covering the entire bit surface. This selective application provides maximum wear protection where it is most needed while significantly reducing the quantity of hard facing material required and associated application costs.

Inventive Principle:

Principle #3Local quality

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 approach enhances the durability and wear resistance of HDD components by maintaining a consistent hardness and microstructure, reducing the risk of cracking and wear, and ensuring longer carbide retention, thus improving the efficiency and lifespan of the bits.

Implementation Method 1

hard facing the horizontal directional drilling (HDD) component with subsequent heat treating

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 2

hard facing the HDD component using laser cladding or plasma transferred arc (PTA) techniques

Methodology Applied

Scientific EffectLaser cladding: Laser Beam Welding

Implementation Method 3

hard facing the HDD component using laser cladding or plasma transferred arc (PTA) techniques

Methodology Applied

Scientific EffectPlasma transferred arc: Electric Arc

Data Source

PatentUS11987889B2Boring bit component with hard face wear resistance material with subsequent heat treatment

Publication Date: 2024.05.21 KONDEX CORP

AI summary

A boring bit or other component for horizontal directional drilling is provided which includes a hard faced layer that is preferably made by a laser cladding bead. A subsequent or post heat treatment is applied to modify the heat affected zone (HAZ) to eliminate or reduce the hard brittle regions and/or softer regions in the base iron or steel material of the HAZ. Further, the hard faced layer may be applied in combination with carbide insert teeth that are embedded within the steel base of the boring bit body, such as by press fitting.