What Is Dye Penetrant Inspection?

Penetrant testing (abbreviated symbol PT), also known as penetrant flaw detection, is a non-destructive testing method for inspecting surface opening defects based on the principle of capillary action.

Penetration testing

Penetrant testing is one of the five major non-destructive testing conventional testing technologies, and is a basic course for non-destructive testing majors in colleges and universities. The goal and starting point of this textbook are based on the teaching of senior undergraduate or graduate students in non-destructive testing majors, while taking into account the needs of student teaching and engineering and technical personnel in vocational colleges. Emphasize the importance of the theoretical foundation, and always use the theoretical foundation throughout the full text; consider the dual needs of teaching and training, and integrate the theory, engineering, and qualification assessment; the textbook layout focuses on the logical relationship between the structural level and the penetration detection process. Content includes introduction, basic principles of penetration testing, penetration testing

Preface Series Preface Preface Chapter 1 Introduction 1
11 Development of Penetrant Detection Technology 1
12 Penetration Testing Features 2
Review Question 3
Chapter 2 Physical and Chemical Basis of Penetration Testing 4
21 Molecular Motion Theory 4
twenty two

Penetrant testing (abbreviated symbol PT), also known as

Penetrant inspection can be widely used to detect the surface opening defects of most non-absorbent materials, such as steel, non-ferrous metals, ceramics and plastics. It can also comprehensively detect defects with complex shapes at one time. It is mainly used for the detection of cracks, white spots, looseness, inclusions and other defects without additional equipment. Corresponding to on-site inspection, portable filling penetration testing agents are often used, including

Penetrant testing is liquid based

Penetration detection method, which uses a liquid dye on the surface of the test material and keeps it on the body surface for a preset period of time. The dye can be a colored liquid that can be recognized under normal light, or it can require special light. Visible yellow / green fluorescent liquid.

This liquid dye is due to "

according to

1. Surface treatment of the test object.

2. apply

Penetrant testing can detect surface opening defects (steel, heat-resistant alloys, aluminum alloys, magnesium alloys, copper alloys) and non-metal (ceramic, plastic) workpieces, such as cracks, looseness, pores, slag inclusions, cold insulation, folding and Oxidation scars and so on. These surface opening defects, especially minute surface opening defects, are generally difficult to find by direct visual inspection.

Penetration testing is not limited by the chemical composition of the workpiece being controlled. Penetrant testing can check both magnetic and non-magnetic materials; ferrous metals, non-ferrous metals, and non-metals.

Penetration testing is not limited by the structure of the workpiece being inspected. Penetration testing can inspect welded or cast parts, rolled and forged parts, and machined parts.

Penetration testing is not limited by defect shape (linear or volumetric defects), size, and orientation. Only one penetration test is required to inspect all defects open to the surface at the same time.

However, penetration testing cannot or is difficult to inspect porous materials, such as powder metallurgy workpieces; nor is it suitable for inspecting defects that are open or blocked due to external factors, such as shot peening or sand blasting, which may block the "openings" of surface defects It is difficult to quantitatively control the quality of the test operation, and it depends on the experience, seriousness and visual acuity of the tester.