Preparatory Questions (Set – 6)

1.  Which of the following processes joins metals plastically? Friction welding Resistance welding Plasma welding None of the above 2.    In submerged arc welding, excessive arc voltage may cause? Excessive penetration Change in weld metal composition Narrow weld width All of the above 3.   In a tensile test, a brittle material would be indicated if the fracture surface? Shows a reduction in size Is flat and featureless Breaks in….

Preparatory Questions (Set – 5)

1.    Which of the following NDT methods can only detect surface breaking defects? MPI DPI UT RT 2.     Which of the following is applicable to electrode efficiency? The mass of metal deposited as a percentage of the mass core wire melted Iron powder electrodes have efficiencies above 100% Electrodes of high efficiencies tend to procedure welds of a smooth flat profile Both a and b 3.    Cellulose….

Preparatory Questions (Set – 4)

1.     Which of the following does not require baking; E 6010 E 7018 Both a & b None of the above 2.     Gamma rays and X-rays are part of a family of waves called Acoustic waves Light waves Electromagnetic waves Transverse waves 3.     Why is hot – pass so-called? Because it is applied at a high amperage Because it is applied when the root is still hot….

Preparatory Questions (Set – 3)

1. Overlap in welds could be influenced by: Welding process Welding position Poor welding technique All the above 2. In MAG/CO2 welding which parameter gives the greatest control of weld appearance during dip transfer or short-circuiting welding? Wire stick-out length Welder’s convenience Wire feed speed Inductance 3. In X-ray work the quality of the radiographic image is assessed by the: Density of the film IQI indicator KVA available Stand-off distance….

Preparatory Questions (Set – 2)

1.  Stress relieving is not helpful in which of the following cases? Softening the steel Lowering the peak residual stress Improving resistance to stress corrosion cracking Improving dimensional stability after machining 2.  Stray arcing may be regarded as a serious defect because: It may reduce the thickness dimension of a component It may cause liquation cracks It may cause hard zones All the above 3.  Slag inclusions would occur with:….

Preparatory Questions (Set – 1)

1. The Discontinuity which results from the entrapment of gas within the weld cross-section is known as: Undercut Lack of penetration Lack of fusion Porosity 2. A discontinuity can be called as defect only when  It is a Linear indication  It is a rounded indication  It exceeds the code limit  if it is a crack 3. Due to the improper termination of the welding arc which discontinuity is likely to….

Welding Symbols (Part -1)

Welding symbols are a set of information conveyed by the design department to the welding Engineer and the welding operator. It contains all the necessary information viz. welding position, dimensions and geometry of the weld, details of groove/fillet, welding process etc. A basic weld symbol consists of three parts namely; Arrow Line Reference Line Tail These are shown in the diagram given below Arrow Line: Arrow indicates the position of….

Types of weld joints

The American Welding Society defines a joint as “the manner in which materials fit together.” there are five basic types of weld joints: • Butt joint. • T-joint. • Lap joint. • Corner joint. • Edge joint. 1. Butt joint: Butt joints are end to end joint, in which the parts lie in the same plane and are joined at the ends. 2. T-joint: In a T-joint (also called as….

TIG Welding (GTAW) Electrodes

In GTAW (Gas Tungsten Arc Welding) also known as TIG welding (Tungsten Inert Gas welding), a non consumable electrode (made up of Tungsten) is used. Tungsten is preferred due to high its high melting point (approximately 3,4100C) and high hardness. Either pure tungsten is used as electrode or it can be alloyed with other elements. These electrodes come in a variety of sizes and lengths. These electrodes are color coded….

Welding Positions

Plate Welding Positions For plate welding we have four different positions namely; Flat position (1G or 1F) Horizontal Position (2G or 2F) Vertical Position (3G or 3F) Overhead Position (4G or 4F) Note: 1. G Designates groove welding (V-groove, J-groove, U-groove etc.)           2. F Designates fillet welds (“T” – Joint, Lap Joint etc.) FLAT WELDING POSITION (1G OR 1F) In flat welding the welders head….

Types of steel – Classification of steel

  Based on the chemical compositions, Steel can be categorized into four basic groups: Carbon Steel Alloy Steel Stainless Steel Tool Steel CARBON STEEL: Carbon steel is the most utilized steel in the industries and accounts for more than 90% of the total steel production. Based on the carbon content, Carbon steels are further classified into three groups. Low Carbon Steel/Mild Steel Medium Carbon Steel High Carbon steel Carbon content….

GMAW (MIG Welding) electrode specification

GMAW (MIG welding) electrodes are designated by some letters and numbers such as ER70S-6, ER90S-6 and E308L etc. I will explain the meaning of these symbols: FOR CARBON STEEL OR MILD STEEL (SUCH AS ER70S-6 OR ER70S-3) Where, ER – Designates electrode or filler rod XX – Designates the minimum tensile strength of the deposited weld metal S – Stands for solid wire Y – Designates the chemical composition of….

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