What is macro examination test?

What is macro examination test?

Macro examination is the procedure in which a specimen is etched and evaluated macro-structurally at low magnifications, typically x10 or lower. Macro examination is a frequently used technique for evaluating steel products such as billets, bars, blooms, and forgings.

What is macro examination What are its objectives?

Macro examination is principally used for checking the quality of welds. A cross section of welded material is polished and etched for examination. Porosity, lack of weld penetration, lack of side wall fusion, poor weld profile and other important defects are checked in accordance with the relevant welding standard.

What is macroscopic assessment?

“Macroscopic” analysis of a product refers to an evaluation of the substance through the use of the unaided senses (primarily sight, smell, or taste) of an individual.

What is the difference between macro and micro examination?

Macro-study is performed with naked eye or with low magnification to study the surface defects of an material, whereas microstructural study is to identify the type of structure, grain size, distribution of particles, grain boundaries etc.

How macro etching is done?

The basic procedure for macroetching is simply to immerse the cleaned specimen into the etching solution, remove it after it has developed a clear structure, rinse it to remove the etchant, and dry. The etchant solution is raised to the specified temperature before immersing the specimen.

How is macroscopic examination done?

The macro examination is performed on the cross section, longitudinal section or through the thickness (‘Z’ direction) of the test sample. The sample is viewed with the unaided eye or at low magnification, usually no greater than 10 times.

What is micro etch test?

Macroetching is done by etching a suitably pre- pared specimen by an appropriate reagent. This test is used extensively for quality control in steel industry, and to determine the ‘tone’ of a heat in billets with respect to inclusions, segregation and structure.

What is meant by metallography?

Metallography is the study of the microstructure of all types of metallic alloys. It can be more precisely defined as the scientific discipline of observing and determining the chemical and atomic structure and spatial distribution of the grains, constituents, inclusions or phases in metallic alloys.

What is the purpose of macro etching?

MACROETCHING is a procedure for revealing the large-scale structure of a metallic specimen, that is, structure visible with the unaided eye, by etching an appropriately prepared surface. The procedure is used in process metallurgy as both a quality-control tool and an investigatory tool.

Why is it important to perform macro etching examination?

This testing is an excellent method in determining the soundness of weld metal by revealing the metallurgical structure produced by the weld such as lack of penetration, lack of fusion, cracking and inclusions.

What is type of macroscopic testing?

Macroetch, Grain Flow, Surface Condition & More Macroscopic Examination, also called Macro Test or Macro Examination, evaluates the quality and consistency of a test sample using only low or no magnification.

What is a Nick break test?

A nick break test is a type of destructive testing that is used to evaluate the quality of a weld. To perform a nick break test, a specimen is prepared out of the weld metal. Stress concentrators are then machined into the specimen.

What is macroeconomics exam?

The Principles of Macroeconomics examination covers material that is usually taught in a one-semester undergraduate course in this subject. This aspect of economics deals with principles of economics that apply to an economy as a whole, particularly the general price level, output and income, and interrelations among sectors of the economy.

How long is the AP Macroeconomics exam?

The AP Macroeconomics Exam is two hours and 10 minutes long. In Section I, students are given 70 minutes to answer 60 multiple-choice questions; in Section II, they must answer three required free-response questions in 50 minutes — one longer essay and two shorter essays.

What is AP Macro test?

The AP Macroeconomics exam measures the students’ knowledge of macroeconomics principles and their ability to reason within the discipline. The AP Macroeconomics exam consists of 60 questions is takes 2 hours and 10 minutes to complete. Students who wish to take the AP exam should expect to pay a $92 fee…