What is the Method of Non-destructive Testing of Seamless Steel Pipes?

Non-destructive testing is a method of non-destructive testing of seamless steel tube materials, workpieces or parts. So what is the method of non-destructive testing of seamless steel tubes?

1. Ultrasonic flaw detection

Piezoelectric ultrasound mainly detects longitudinal defects and is used to measure diameter and thickness. Electromagnetic ultrasound can detect longitudinal and lateral defects. The main grades are C3 (L1), C5 (L2), C8 (L25), C10 (L3), C12 (L4). Among them, C5 is used for cold processing of high-pressure boiler tubes; C8 is used for thermal processing of high-pressure boiler tubes; C10 and C12 are used for steel pipes for other purposes.

2. Eddy current testing
Mainly used for surface and near surface flaw detection. Penetration eddy current testing mainly detects lateral defects and delamination. Eddy current can also be used to measure thickness, hardness, strength, diameter and distance. Acceptance levels A and B can be used as alternative methods for water tightness testing. Class B acceptance shall be negotiated by the supplier and the buyer and specified in the contract. The sample tube has drilled holes (through holes) and longitudinal grooves.

3. Magnetic Leakage Testing
It is mainly used for the detection of surface and near-surface defects (such as cracks, folds, sandwiches, chutes, cold preservation, etc.). The acceptance level is l2, l3, l4 (5%, 10%, 12.5% of the nominal wall thickness of the grooved steel pipe on the outer surface), and 8% for l2.5.

4. Magnetic Particle Testing
It is mainly used to detect defects such as surface and near-surface cracks. There are three types of standard samples: Type A, Type B and Type C. Magnetic particle inspection only detects 

longitudinal and transverse damage within 400mm of the tube end.

Tips: ASTM A53 covers seamless and welded steel pipe with nominal wall thickness. The surface condition is usually black and hot-dipped galvanized. ASTM A 53 is produced mainly for pressure and mechanical applications, and is also used for transport of steam, water, gas line pipes.

ASTM A53 Gr.B is the grade in ERW high frequency welded pipe, divided into A and B grades. ASTM is only a set of specifications. ASTM steel pipe A53 A corresponds to the Chinese standard GB8163 raw material is 10# steel, and A53 B corresponds to the Chinese standard GB8163 raw material 20#.
For example: ASTM (standard) A53 (grade) gr is grade (abbreviation of grade) b (grade B)