Oilfield Drill Pipe Upset Forging with Continuous Induction Heating

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Solution Overview

Problem

The existing process for manufacturing oilfield drill pipes requires re-heating and re-forging of certain pipe types during the upsetting process, leading to inefficiencies and increased time due to the need for multiple trips through the manufacturing process, especially for pipes that cool rapidly and require a third stage of upsetting.

Innovation Solution

The implementation of a continuous induction heating system using walking beams and infrared pyrometers to maintain the pipe end at optimal temperature, with an auxiliary induction heating coil for re-heating as needed, and a robot for efficient transport between heating and forging stages, minimizing the need for repeated full process runs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the pipe is run through the entire upsetting process multiple times to accommodate rapid cooling and third stage upsetting, then the pipe can be properly forged to final dimensions, but the production time and process complexity increase significantly

Engineering Contradiction:

Improveforging temperature maintenanceVSAvoidproduction cycle time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The upsetting process is divided into discrete stages with separate heating zones. The first heating zone prepares the pipe for initial upsetting, while the second heating zone is specifically positioned to reheat the pipe end between the second and third upsetting stages. This segmentation allows each heating zone to serve its specific function without requiring complete process repetition.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pipe end is preheated in the first heating zone before entering the upsetting process. Additionally, the second heating zone is positioned to provide preliminary reheating before the third upsetting stage, ensuring the pipe end reaches optimal temperature in advance rather than requiring a complete process restart.

Inventive Principle:

Principle #10Preliminary action

2Strength

If the pipe end is heated to high temperature for forging, then the material becomes sufficiently plastic for shaping, but heat loss during transport and processing causes temperature to drop below forging requirements

Engineering Contradiction:

Improvematerial plasticityVSAvoidpipe end temperature

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The heating zones are positioned to provide continuous heating throughout the upsetting process. The first heating zone operates continuously to maintain pipe end temperature during initial upsetting stages, and the second heating zone activates when needed to maintain temperature continuity through the third upsetting stage, eliminating temperature dropouts.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The second heating zone acts as an intermediary thermal buffer between the first heating zone and the third upsetting stage. It receives heat from the first zone and delivers it to the pipe end at the critical moment before third stage upsetting, mediating the temperature maintenance function.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the pipe is transported through the entire manufacturing process multiple times, then temperature requirements can be met, but machinery wear and operational efficiency decrease

Engineering Contradiction:

Improvetemperature controlVSAvoidprocess efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Multiple heating functions are merged into a single integrated heating system with two zones positioned along the upsetting line. This combines the benefits of repeated heating with the efficiency of a single-pass process, eliminating the need for multiple complete trips through the manufacturing process while maintaining temperature control reliability.

Inventive Principle:

Principle #5Merging (Combining)

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 significantly improves the efficiency and reduces the time required for the upsetting process by allowing continuous heating and re-heating as necessary, eliminating the need for multiple trips through the entire process and minimizing wear on machinery.

Implementation Method 1

Pipe is conveyed via a walking beam though one or more induction heating coils designed to heat one end of the pipe to forging temperature

Methodology Applied

Scientific EffectInduction heating: Induction Heating

Implementation Method 2

The temperature is monitored and controlled via two infrared pyrometers

Methodology Applied

Scientific EffectInfrared radiation detection: Infrared Radiation

Data Source

PatentUS8539807B2Process for making upsets for oilfield drill pipe

Publication Date: 2013.09.24 NAT OILWELL VARCO LP

AI summary

Pipe to be upset is conveyed via walking beam though a series of induction heating coils and one end is heated to a maximum temperature of 2350 degrees F. Thereafter, a robot transports the pipe into a forging machine where the pipe end is upset in one or more die pockets. For those types of pipes where the pipe end temperature falls below an acceptable temperature during upsetting, the robot delivers the pipe end to an auxiliary induction heating coil and is re-heated to an acceptable forging temperature. The robot then transports the pipe back into the forging machine where the pipe end is forged to its final upset dimensions.