On-line eddy current testing system for stainless steel straight welded pipe ECN1002/EFN1002

Project Overview

◆Customers produce stainless steel straight seam welded pipes. On-line eddy current automatic flaw detection system is installed on the welded pipe machine.

◆Characteristics of argon arc welding/plasma welding: This welding method is mainly used for stainless steel and titanium alloy longitudinal welded pipes. The general welding speed is low (0.52-10m/min).

◆The optimum detection speed of ordinary eddy current on-line flaw detector is >5m/min. The ultra-low speed eddy current flaw detector really solves the problem of low-speed on-line detection of argon arc welding/plasma welding. The lowest detection speed is 0.5 m/min. The detection sensitivity and the ratio of performance to noise exceed the relevant national standards.

◆Option of through-type/saddle-type detection: It is recommended that the through-type detection be used in the specification of φ0-40. The advantage is that the weld and pipe body can be detected. The disadvantage is that each specification needs to be equipped with a probe and guide sleeve. >φ40 suggested saddle probe, a probe can cover a wide range of specifications, a certain range of specifications do not need to replace the probe. Only weld position defects can be detected..

◆For square and special-shaped tubes detection, saddle type is mainly used.

Detecting Workpiece Information

Detection Objects Name                              Stainless steel straight welded pipe, round pipe

Material                                                               Stainless steel (2, 3 series, etc.)

Dimension Specification                                                         0-40

Weld Width                                              ≈0-5mm, weld angle deviation of 5 mm is acceptable

Length                                           On-line flaw detection of length, flying saw cutting pipe or coil after flaw detection

Bending Degree                                               1.5mm/m ( Of the detection station)

Circular Degree                                                         Circular tube≦0.1mm

Roughness                                                     Pipe wall and weld (with burrs)≦3.2

Hardness                                                                             Harder

On-line Speed                                Welding speed: 0.50≦750m/min ( Instrument detection speed: 0.52-750m/min)

Detection Part Temperature                               80-100°C or normal temperature

Detection Requirement and Accuracy Standard

                                                               Executive Standard of Detection

Number of Standard                                         Name of Standard                                                                  Grade

GB/T 14480-2015            Nondestructive Testing Instrument     Eddy Current Testing Equipment                        /

GB/T 7735-2016               Automatic eddy current testing for seamless and welded steel pipe               The Highest Grade

                                         (except submerged arc welding) defects       

Technical Parameter of the System

Name of the System: On-line eddy current testing system for stainless steel straight welded pipe

Type: ECN/EFN1002

Detection Method: On-line saddle dual-channel eddy current detection

Control Mode: Automatic+Manual

Instrument and Probe: Eddy current instrument; Dual Channel Digital High Intelligence Eddy Current Flaw Detector and Probe

Detection Platform: Core detection platform independently developed

Brief Introduction of Detection Operation:

Adjust the technical parameters and standard samples of flaw detector according to the testing requirements;

Adjust the position of probe and probe according to workpiece specifications;

The flaw detection system detects the workpiece, alarms and marks;

Adjust welding equipment (mould, welding joint) according to alarm;

Data recording, storage and analysis are carried out by the flaw detection host;

Automatically form flaw detection report.

Important Parameters of the System

Name                                                 Technical Parameter                                               Remarks

End Blind Area                                           ≦50m                                               Depending on the test speed

Stability                                              After 16 hours≦2dB                                             Test sample

Accuracy of Jet Printing                              ±50mm                                                         Test sample

Omissive Judgement Rate                              0%                                                             Test sample

Misreporting Rate                                         ≦2%                                                           Test sample

Test Speed                                          0.50≦750m/min                                       Depending on customer's welding speed, 

                                           Argon arc welding will be adjusted according             the fastest speed can reach 750m/min     

                                            to customer's welding speed.                                     (this project is stainless steel argon 

                                                                                                                             arc welding, the speed is slower)

Principle of Through Type Eddy Current Testing

       Eddy current detection is to establish alternating magnetic field by approaching conductor to the coil with alternating current (referred to as the probe). The alternating magnetic field passes through the conductor and produces electromagnetic induction with it, and establishes eddy current in the conductor. The eddy current in the conductor will also produce its own magnetic field.