基于美国ASME标准的磁粉检测规程

CONTENTS

1.Scope

2.Qualification of NDE Personnel.

3.Procedure

4.Magnetizing Equipment and Material

5.Surface Preparation

6.Examination

7.Evaluation

8.Demagnetization

9.Reexamination for repaired Area and Nonconformity Control

10.Post Cleaning

11.Report

SUSPENSION CONCENTRATION CALIBRATION RECORD MAGNETIC PARTICLE EXAMINATION INSTRUCTION MAGNETIC PARTICLE EXAMINATION REPORT

1.Scope

1.1.This procedure is applied to detect cracks and other discontinuities on or near the surface of ferromagnetic materials, using wet magnetic particle and AC or DC yoke technique with continuous magnetization method 1.

2.This procedure is applied to welds and materials of ASME Code pressure vessels fabricated according to ASME Code Section Ⅷ Division

1.

2.Qualification of NDE Personnel

All personnel performing magnetic particle examination shall be qualified and certified in accordance with the requirements of HT’s Written Practice for NDE Personnel Training, Examination, Qualification and Certification based on the requirements of“SNT-TC-1A”(Current Code accepted edition)

3.Procedure

This procedure shall be supplemented by MAGNETIC PARTICLE EXAMINATION INSTRUCTION which shall be issued to every product to be examined and in which more detail parameters are specified. The Instruction shall be prepared by level Ⅱ,approved by level ⅢNDE examiner,

4.Magnetizing Equipment and Materials

4.1 Magnetizing equipment

4.1.1The magnetizing equipment shown in Table 1 shall be used.

4.1.2.Calibration of Equipment

The magnetizing equipment shall be calibrated at least once a year, or whenever the equipment has been damaged. If the equipment has not been in use for a year or more, calibration shall be done prior to first use. The magnetizing equipment shall be calibrated in accordance with the requirements of MAGNETIC PARTICLE EQUIPMENT CALIBRATION PROCEDURE

4.2.Magnetic Particle Field Indicator

The magnetic particle field indicator shown in fig1 shall be used to demonstrate the direction of magnetic flux

4.3 Examination Medium

4.3.1Magnetic particle shown in Table 2 shall be used. The color of the particles shall provide adequate contrast with the surface being examined. If it is not adequate, another color shall be select and redemonstration shall be required

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4.3.2.Water Vehicles and Suspension

Mixing ratio of rater medium magnetic suspension is 11.0-22.0g magnetic slurry per 1000ml water.

4.3.3 Concentration of Wet Magnetic particle Suspension

The concentration is normally determined by measuring its settling volume through the use of an ASME pear-shape centrifuge tube.

Before sampling, run the suspension for at least 30-min. to assure thorough mixing of all particles. Take a 100ml portion of the suspension and allow it to settle approximately 30 min. The volume settling out at the bottom of the tube is indicative of the particle concentration in the bath. Bath concentration shall be form1.2 to 2.4 ml per 100ml vehicles. The calibration shall be performed by MT levelⅡor Ⅲ and reviewed by MT level Ⅲ NDE Examiner. The calibration results shall be recorded on CALIBRATION RECORD FOR SUSPENSION CONCENTRATION.

4.4 Illumination

When natural light is not enough for examination and evaluation, adequate illumination is required ensuring adequate sensitivity during the examination and evaluation.

5. Surface Preparation

5.1 Satisfactory results are usually obtained when the surface is in the as-welded,