Inner-Hole Wear-Resistant Layer via Filler Core Rod Welding

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Solution Overview

Problem

The current surfacing welding method for applying a wear-resistant layer on the inner wall of the hook claw in nuclear power plant control rod driving mechanisms has a low pass rate due to its poor controllability, low production efficiency, and high manufacturing cost, primarily because of the difficulty in welding small diameter holes.

Innovation Solution

A method involving drilling a prefabricated hole with a larger diameter, inserting a filler core rod, and performing filling welding or self-fusion welding to create a wear-resistant layer, which simplifies the welding process and improves the quality and efficiency of the wear-resistant layer application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If manual oxyacetylene welding is used to apply wear-resistant alloy layer on the inner wall of small diameter hole, then wear resistance is improved, but operation difficulty increases and pass rate decreases

Engineering Contradiction:

Improvewear resistanceVSAvoidoperation difficulty

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

Instead of welding the wear-resistant layer directly on the inner wall of the small diameter hole (difficult operation), the invention inverts the approach by welding a filler core rod with wear-resistant material on the outer side, then machining it to form the hole. This transforms the difficult internal welding operation into an easier external welding operation followed by machining.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention applies preliminary action by first welding the filler core rod that contains the wear-resistant material, then subsequently machining the hole through it. This preliminary welding action prepares the wear-resistant layer before the hole is finalized, avoiding the need to perform precise welding inside the small hole.

Inventive Principle:

Principle #10Preliminary action

2Strength

If manual oxyacetylene welding is used for small hole wear-resistant layer, then wear resistance is achieved, but production efficiency decreases

Engineering Contradiction:

Improvewear resistanceVSAvoidproduction efficiency

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The invention replaces the manual oxyacetylene welding mechanical system with an automatic welding system for applying the wear-resistant layer on the filler core rod. This substitution significantly improves production efficiency while maintaining the wear-resistant properties of the final product.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If manual oxyacetylene welding is used for small hole surfacing, then wear-resistant layer is formed, but manufacturing cost increases

Engineering Contradiction:

Improvewear resistanceVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The invention replaces the expensive manual oxyacetylene welding process with a more cost-effective automatic welding process for applying the wear-resistant layer, thereby reducing manufacturing costs while maintaining product quality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Strength

If wear-resistant layer is applied on inner wall of hole, then wear resistance is improved, but controllability decreases

Engineering Contradiction:

Improvewear resistanceVSAvoidcontrollability

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The invention inverts the welding location from the difficult-to-control inner wall of the hole to the easier-to-control outer surface of the filler core rod. This inversion improves controllability of the welding process while the subsequent machining ensures the final hole dimensions and wear-resistant layer properties meet specifications.

Inventive Principle:

Principle #13The other way round (Inversion)

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 method significantly reduces the difficulty of the welding operation, enhances the quality and pass rate of the product, and facilitates mass production by using automatic welding, thereby improving the overall manufacturing process.

Implementation Method 1

embedding the filler core rod into the prefabricated hole, and filling the gap between the filler core rod and the prefabricated hole by filling welding or self-fusion welding

Methodology Applied

Scientific EffectWelding: Welding

Data Source

PatentEP3780005B1Preparation method of wear-resistant layer on the inner wall of the hole for increasing the pass rate of the product

Publication Date: 2021.07.21 YU JIE

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AI summary

The present invention discloses a preparation method of wear-resistant layer on the inner wall of the hole for increasing the pass rate of the product, the preparation method used to obtain a hole with an inner diameter D and a wear-resistant layer on the part, comprises the following steps: S1, drilling a prefabricated hole with an inner diameter of D1 on a part, D1>D; obtaining a filler core rod, the outer diameter of the filler core rod is less than D1 and greater than D; S2, embedding the filler core rod into the prefabricated hole, and filling the gap between the filler core rod and the prefabricated hole; S3, drilling the hole with the inner diameter D on the filler core rod. The preparation method can effectively reduce the difficulty of surfacing welding on the inner wall of the hole.