CTOD test, what is it?

What is CTOD Test? CTOD test is used to determine fracture toughness (fracture resistance) of a material with an artificial crack, and a test to determine crack tip opening displacement to generate unstable fracture (limit CTOD value). It is usually carried out by loading a CTOD test specimen on a 3-point bending system as shown in below figure. These tests are made using a full-plate thickness specimen containing a machined notch which is extended by fatigue cracking.When a material having a defect is applied a load, a crack will propagate rapidly originating from the defect, resulting in fracture at a … Continue reading CTOD test, what is it?

CVN Impact test specimens location for welded structure

Charpy V-notch (CVN) impact testing of the welded steel product. A required toughness level is commonly expressed for a particular test temperature (which may be different from the lowest anticipated service temperature) at which a minimum CVN impact energy value (KVmin), shall be achieved. The approximate relationship between the CVN energy-temperature curve and the fracture behavior of a welded steel component. Here are the samples of Typical impact test specimens will be machined and tested according to AWS D1.1, ASME B31.3, ASME VIII, and other construction codes. Notch location: 1 Centreline of the weld2 Fusion line3 In HAZ, 1mm from … Continue reading CVN Impact test specimens location for welded structure

Corrosion Test Standard Selection

Corrosion resistance is an important characteristic of Ni – base alloys and weldments. There are many acceptance tests specified in ASTM or EN ISO and other literature to evaluate the corrosion resistance of alloys for use in different environments. In this article, for common requirement in project specification. Intergranular corrosion, pitting, crevice or general corrosion assessment that will be took into discussion. I will try to describe the differences of the tests for applicable common standards (ASTM/ISO) and point out which alloys the tests are intended for, and recommends the most appropriate test when none is specified. The Huey test … Continue reading Corrosion Test Standard Selection

ASTM E8 vs ASTM A370 (Tensile Test)

WHAT ARE THEY MEASURE? ASTM E8 / E8M measures the tensile properties of metallic materials in any form at an ambient temperature between 10 – 38 degrees Celsius (50 – 100 degrees Fahrenheit). Though ASTM E8 / E8M measures many different tensile properties, the following are the most common: Yield Strength – The stress at which a material becomes permanently deformed Yield Point Elongation – The phase during which a material is transitioning from elastic behavior to plastic behavior Tensile Strength – The maximum force or stress that a material is capable of sustaining Reduction of Area – A measurement of the ductility of … Continue reading ASTM E8 vs ASTM A370 (Tensile Test)

Changing of Electrode Brand name or Trade name in welding essential variable

If welding is to be performed according to a welding procedure specification, it is possible that changing the electrode manufacturer will invalidate the approval of the procedure to the code/standard on which it was based. The manufacturer or ‘trade name’ … Continue reading Changing of Electrode Brand name or Trade name in welding essential variable

What is CTOD test?

Related specifications BS 7448 Parts 1- 4 Fracture Mechanics Toughness Tests BS 7910 Guide on Methods for Assessing the Acceptability of Flaws in Metallic Structures. ASTM E1820 Standard Test Method for Measurement of Fracture Toughness.  BS EN ISO 15653 Metallic Materials – Method of test for the determination of quasistatic fracture toughness of welds Applicable CTOD Standards CTOD testing is performed on set of 3 no. of test samples; that are representative of an actual component thickness (B) and is subjected to in-service (representative) loading conditions and minimum design temperature. The test specimen has machined Notch along with a genuine … Continue reading What is CTOD test?