Glossary
1st Type Weld Phenomenon
ERW weld condition which has low weld periodity leading to formation of cold weld. Also known as low ERW weld periodity.
3rd Type Weld Phenomenon
ERW weld condition which has high weld periodity leading to formation of penetrators. Also known as high ERW weld periodity
ANSI
American National Standards Institute
API
American Petroleum Institute
Bend Test
Destructive test where the weld is put under tension through bending
Black Spot
ERW Weld defect which is visible as a black spot on the fracture surface after a destructive test. Also known as a Penetrator
Blipping
Periodic discharge of molten bead
Blow Hole
ERW Weld defect which is visible as a shiny spherical spot on the fracture surface after a destructive test
Bond Line
Line visible in a macro where the strip edges are fused together. It is also known as the fusion line
Brittle Weld
ERW Weld defect with a brittle fusion line
Bug Hole
ERW Weld defect visible as a small hole through the fusion line. Also known as a pin hole
Bulge Test
Destructive test where the weld is put under tension by mechanically expanding the tube/pipe by bulging
Burst Test
Destructive test which determines the actual yield strength and ultimate tensile strength by pressurizing the inside of the tube/pipe
Capability Indices
Measure of the ability of a process to satisfy established specifications
Cast Weld
ERW Weld defect where the fusion line shows a cast microstructure
Caved Weld
ERW Weld where the outside edges meet before the inside edge
Cold Weld
ERW Weld defect where insufficient weld fusion is achieved. Also known as Paste Weld and Weak Weld
Contact Welder
ERW Welder that uses sliding contacts to introduce current flow along the strip edge
Control Chart
Graphical chart used to analysis process attributes by statistical method
Cpm
Capability indice that measures variation from target and ability to meet specification
Cross Weld
Welded joint between coils of strip, also called end weld
Destructive Test
Test which destroys the produce
Downtime
Measure of unproductive process time
Ductility
Ability of steel to deform plastically without fracture
Eddy Current Test
Non-destructive testing method utilizing a magnetic field
Elongation
Increase in test sample length during a tensile test
End Weld
Welded joint between coils of strip, also called cross weld
ERW
Electric Resistance Welding heats strip edges, by conducting low voltage high current electricity across the strip edges, through rotary electrode
Event Log
Historical log showing process event
Expansion Test
Destructive test where the weld is put under tension by mechanically expanding the tube/pipe
Failure Mode Analysis
Method used to identify possible product or process failure and its cause
Ferrite
Ferromagnetic material used inside impeder
Fin Pass
Final forming rolls used for strip forming and strip edge preparation
Flange Test
Destructive test where the weld is put under tension by mechanically expanding the tube/pipe onto a flange
Flare Test
Destructive test where the weld is put under tension by mechanically expanding the tube/pipe onto a cone
Flattening Test
Destructive test where the weld is mechanically stressed by flattening the tube/pipe between parallel plates. The inside or the outside of the weld can be put under tension by the weld orientation during the test
Flow Line
Elongation of inclusions and other structures, formed during the strip rolling process, which are visible in a macro and micro
Forming
Section of mill used to form the strip in preparation for ERW welding
Fusion Line
Line seen in weld macro where the strip edges are fused together. It is also known as the bond line
HAZ
Heat affected Zone
HFI Welding
High Frequency Induction Welding heats the strip edges by inducing current flow along the strip edges. It is still commonly known as ERW Welding
High ERW Weld Periodity
ERW weld condition which has high weld periodity leading to formation of penetrators. Also known as 3rd type weld phenomenon
Hydroforming
Process where tube is formed to the shape of a die using pressurized water
Hydrostatic Test
Mechanical test which puts the weld under stress by pressurizing the inside of the tube/pipe
Inclusion
ERW Weld defect where nonmetallic materials and oxides are present in the fusion line
Induction Coil
Device that induces current flow along the strip edges in ERW Welding
Induction Welder
ERW Welder that uses an induction coil to induce current flow along the strip edge
Impeder
Device that increases the impedance of current flow inside the tube/pipe, forcing current flow along the strip edges, during ERW Welding
ISO
International Organization for Standardization
ISO 9000 Series
Standards established by ISO to judge the adequacy of company quality system
Lack of Fusion
ERW Weld defect where insufficient weld fusion is achieve
Leaker
ERW Weld defect found through hydrostatic testing
Low ERW Weld Periodity
ERW weld condition which has low weld periodity leading to formation of cold weld. Also known as 1st type weld phenomenon
Macro Structure
Optical examination of weld cross section, through low power optics, after polishing and acid etching
Mean
Statistical measure of sample average
Micro Structure
Optical examination of weld cross section through, high power optics, after polishing and acid etching the produce
Mill Coolant
Liquid used in ERW weld mills, which acts as a coolant and lubricant
Mill Scale
Surface scale produced while working steel strip
Mill Setup
Adjustment of rolls and other equipment used on ERW weld mill
Misalignment
Measure of how well the strip edges are aligned. It is also known as the Mismatch
Mismatch
Measure of how well the strip edges are aligned. It is also known as the Misalignment
Molten Bead
Molten material forced from strip edges during ERW welding
NDT
Product testing methods which do not destroy the product. Also known as Nondestructive Testing
Nondestructive Testing
Product testing methods which do not destroy the product. Also known as NDT
Normalizing
Heat treatment method where the steel is heated above the transformation range and then cooled
OCTG
Oil Country Tubular Goods made to API specification
Oxide
Metal oxide
Pareto Chart
Bar chart that displays in descending order the frequency of event
Paste Weld
ERW Weld defect where insufficient weld fusion is achieved. Also known as Cold Weld and Weak Weld
Parallel Edges
ERW Weld where the strip edges are parallel to each other
Peaked Weld
ERW Weld where the inside edge meet before the outside edge
Pin Hole
ERW Weld defect visible as a small hole through the fusion line. Also known as a bug hole
Pipe
Tubular product for carrying liquid or gas
Penetrator
ERW Weld defect which is visible as a black spot on the fracture surface after a destructive test. Also known as a Black Spot
Periodity
Cyclical movement of the welding position, which occurs during ERW welding. Also known as Periodicity
Periodicity
Cyclical movement of the welding position, which occurs during ERW welding. Also known as Periodity
Popper
ERW Weld defect which fails on the mill during sizing
Pre-arc
Short circuit across the weld vee, contacts, or welder lead
Procedure
Set of conditional instructions for performing a task
Process Capability
Ability of a process to produce defect free produce
Process Control
Mechanisms that control a process
Process Map
Visual representation of process workflow
Process Variation
Fluctuation in process output
Proximity Effect
Electrical phenomenon where current is attracted to the strip edges in the weld vee
Pucker
ERW Weld defect found through flattening test
Root Cause
Source of defect or problem
Run Chart
Line graph showing process attributes over time, can be used to examine process shifts, and process variation
Scarfing
Cutting operation which removes the weld bead
Seam Guide
Device used to control the weld vee
Sigma
Standard deviation of a sample
Skelp
Steel of specific thickness and width, used to produce tube/pipe. Also called Strip
Skelp Burr
Protrusion along the edge of the skelp caused during slitting. Also called Strip Burr
Skelp Edge Condition
Condition of the skelp edge. Also called Strip Edge Condition
Skelp Edge
Edge of the steel skelp. Also called Strip Edge
Skelp Thickness
Thickness of the steel skelp. Also called Strip Thickness
Skelp Width
Width of the steel skelp. Also called Strip Widtd
Skin Effect
Electrical phenomenon where current is concentrated on the strip surface
Slitting
Process of shearing skelp to required widtd
Specification
Customers expectation for product attribute
Spume
Spherical particle of metal ejected from the weld vee during ERW welding
Squeeze Out
Material forced from strip edges during ERW welding. Also known as Weld Bead and Weld Upset
Squeeze Rolls
Rolls used to squeeze the strip edges together during ERW welding. Also known as Weld Roll
Statistical Analysis
Analysis of process attributes by statistical method
Statistical Process Control
Application of statistical methods to identify and control process variation
Strip
Steel of specific thickness and width, used to produce tube/pipe. Also called Skelp
Strip Burr
Protrusion along the edge of the strip caused during slitting. Also called Skelp Burr
Strip Edge Condition
Condition of the strip edge. Also called Skelp Edge Condition
Strip Edge
Edge of the steel strip. Also called Skelp Edge
Strip Thickness
Thickness of the steel strip. Also called Skelp Thickness
Strip Width
Width of the steel strip. Also called Skelp Width
Tolerance
Specified allowance for product attribute
Tube
Tubular produce
Virtual Macro®
Monitoring and control system that identifies defective ERW welds, causes, and corrective actions required
Ultimate Tensile Strength
Measure of the maximum force divided by the original cross sectional area, during a tensile test. Also known as Tensile Strength or Ultimate Strength
Ultrasonic Testing
Non-destructive testing method utilizing sound waves
Weak Weld
ERW Weld defect where insufficient weld fusion is achieved. Also known as Cold Weld and Weak Weld
Weld Bead
Material forced from strip edges during ERW welding. Also known as Squeeze Out and Weld Upset
Welding Contacts
Sliding contacts that introduce current flow along the strip edge
Weld Periodity
Cyclical movement of the welding position, which occurs during ERW welding. Also known as Weld Periodicity
Weld Periodicity
Cyclical movement of the welding position, which occurs during ERW welding. Also known as Weld Periodity
Weld Power
Electrical power outputted from the contact or induction welder
Weld Rolls
Rolls used to squeeze the strip edges together during ERW welding. Also known as Squeeze Rolls
Weld Stand
Roll stand that holds the weld rolls
Weld Upset
Material forced from strip edges during ERW welding. Also known as Squeeze Out and Weld Bead
Weld Vee
As the tube/pipe strip edges close, they form a vee, with an apex slightly ahead of the weld rolls
Weld Vee Angle
Angle of the weld vee
Weld Vee Apex
Point the strip edges meet in the weld vee
Weld Vee Length
Length of the weld vee
White Spot
ERW Weld defect which is visible as a white spot on the fracture surface after a destructive test
Yield
Percentage measure of good product over total product produced
Yield Strength
Stress required to produce permanent deformation