Piercer Plug Injection Hole Placement for Seamless Pipe Quality

Solution Overview

Problem

Existing piercers often cause inner surface defects during the piercing of metal billets due to the Mannesmann effect, and the injection of lubricants can lead to friction-related issues, erosion, and clogging of the injection holes, which complicates the seamless pipe manufacturing process.

Innovation Solution

A piercer design with a plug featuring an injection hole on the cylindrical portion, allowing lubricant injection without contacting the billet, and a mandrel with a through hole for lubricant flow, preventing high-pressure lubricant injection and minimizing heat exposure to the injection hole, thus reducing the risk of lubricant solidification and clogging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lubricant is injected from an injection hole provided at the tip end of the plug, then the friction coefficient of the plug is reduced, but the injection hole could be destroyed by contacting the billet and the lubricant must be injected at high pressure

Engineering Contradiction:

Improvereduction of inner surface defectsVSAvoiddamage to injection hole

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The plug is divided into multiple functional portions: a tip end portion for initial contact and hole formation, a cylindrical portion with the injection hole for lubricant delivery, and a barrel portion for deformation control. This segmentation allows the injection hole to be positioned in a region that does not contact the billet, preventing damage while maintaining lubrication function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cylindrical portion acts as an intermediary structure between the tip end portion and the barrel portion. It provides a protected environment for the injection hole, allowing lubricant to be delivered to the working region without the hole itself being exposed to direct billet contact and damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If the injection hole is provided at the barrel portion adjacent to the cylindrical portion, then lubricant can be supplied, but the billet contacts the upper part of the opening causing inner surface defects and eroding the injection hole

Engineering Contradiction:

Improvelubricant supplyVSAvoidinner surface quality

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The plug is divided into multiple functional portions: a tip end portion for initial contact and hole formation, a cylindrical portion with the injection hole for lubricant delivery, and a barrel portion for deformation control. This segmentation allows the injection hole to be positioned in a region that does not contact the billet, preventing damage while maintaining lubrication function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the plug are designed with different functions and properties. The cylindrical portion is specifically designed to have a fixed outer diameter that creates a clearance from the billet, making this local region suitable for housing the injection hole without billet contact, while other portions perform different functions.

Inventive Principle:

Principle #3Local quality

3Force

If high pressure is used to inject lubricant, then the lubricant can be delivered against billet resistance, but the injection hole may be eroded and clogged

Engineering Contradiction:

Improvelubricant injection pressureVSAvoidinjection hole integrity

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The cylindrical portion acts as an intermediary structure between the tip end portion and the barrel portion. It provides a protected environment for the injection hole, allowing lubricant to be delivered to the working region without the hole itself being exposed to direct billet contact and damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The clearance between the cylindrical portion and the billet automatically serves to protect the injection hole from direct contact with the billet. The geometry of the plug design itself provides the protection mechanism, eliminating the need for additional protective structures.

Inventive Principle:

Principle #25Self-service

4Reliability

If the plug surface friction coefficient is reduced to prevent Mannesmann effect fracture extension, then the advancing speed of the billet increases, but the rotary forging effect is restricted

Engineering Contradiction:

Improveprevention of inner surface defectsVSAvoidrotary forging effect

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The friction coefficient parameter is changed by introducing lubricant injection. This parameter change reduces the harmful effect of friction that would otherwise extend the Mannesmann fracture, while the controlled lubrication maintains sufficient friction for the rotary forging effect to occur in the deformation zone.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Lubrication is applied locally at specific portions of the plug surface where friction causes harmful effects, while maintaining higher friction in regions where rotary forging is needed. This localized control of friction properties allows both objectives to be achieved.

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

The solution effectively prevents inner surface defects and maintains the integrity of the injection hole, ensuring a smoother piercing and rolling process with reduced friction and heat impact, resulting in higher-quality seamless pipes.

Implementation Method 1

the friction coefficient of the plug surface should be reduced. The reduction in the friction coefficient of the plug surface increases the advancing speed of the billet in the process of piercing

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

The reduction in the friction coefficient prevents the plug from being worn or eroded. Therefore, inner surface defects caused by irregularities formed on the plug surface because of the friction or erosion can be prevented

Methodology Applied

Scientific EffectWear: Wear

Implementation Method 3

a fracture due to the Mannesmann effect is caused in the center of the billet upstream of the plug tip end. The fracture due to the Mannesmann effect is subjected to circumferential shear distortion by the inclined rolls and the plug during the piercing

Methodology Applied

Scientific EffectShear stress: Shear Stress

Data Source

PatentUS8333092B2Piercer, plug and method of manufacturing seamless pipe or tube

Publication Date: 2012.12.18 NIPPON STEEL CORPORATION

AI summary

A plug 2 used for a piercer according to the invention includes a tip end portion 23, a cylindrical portion 24, a barrel portion 25, a mandrel coupling portion 22, and an injection hole 21. The injection hole 21 penetrates from the surface of the cylindrical portion 24 to the surface of the mandrel coupling portion 22 and an externally supplied lubricant is injected from the hole. A clearance forms between the pierced material and the cylindrical portion 24. The injection hole 21 is formed at the cylindrical portion 24, and therefore the material in the process of piercing does not contact the injection hole 21. Therefore, an inner surface defect attributable to the contact between the material and the injection hole 21 can be prevented from being generated.