Dye penetrant inspectionδσ (DP), also called Penetrant Testβ ♣✘ing(PT), is a widely applied and ∏£ low cost inspection method ​×£used to check surface-breaking de♥₩fects in ferrous materials includi€♦≤ng our bolt products. 

For ferrous components magnetic-partic≥<✘δle inspection is oft∏>£en used instead for its su∞♦₩bsurface detaction capability. Li £δ•quid penetrate inspe✘&§ction is often used to dete ₹ct casting, forging and welding su"♥Ω★rface defects such as hairline ÷€★cracks, surface porosity, leaks i♦€γn new products.

Inspection steps:

1. Pre-cleaning 

The test surface is cleaned to remov䧧e any dirt, paint, oil, grease or ♥§✘→any loose scale that could either₩↔↑ keep penetrant out of a defect ∑™≈or cause irrelevant orε> false indications.

2. Application of penetrant

The penetrant is then applied t∑​αo the surface of the item being tested₹λ♥∑. The penetrant is usually a brilliant"♠ coloured mobile fluid with φ↓≥high wetting capability.

3. Excess penetrant removal 

The excess penetrant is the‍✔‌πn removed from the surface.

4. Application of develope®‌  r

After excess penetrant has been☆γ∑ removed, a white de↔>∞€veloper is applied toαβ♠ the sample. 

5. Inspection

The inspector will use v Ω♥φisible light with adequate inten↕≠♦÷sity for visible dye penetrΩ≥Ω♠ant. 

6. Post cleaning

The test surface is often cleaned after✔↕ inspection and recording of defe≥  ♦cts, especially if post-inspectβ♥ion coating processe α↓s are scheduled.

Advantages:

Low cost, high test speed