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….

Gas Metal Arc Welding (GMAW/MIG)

Gas Metal Arc Welding (GMAW) is also known as Metal Inert Gas Welding (MIG welding). In this process, consumable electrode is used in the form of wire and a shielding gas such as Argon, Helium, Carbon dioxide or a mixture of these gases are used. These gases shield the molten weld pool from atmospheric contamination. The shielding gas is allowed to flow through the weld gun. Electrode of MIG welding….

Shielded Metal Arc Welding (SMAW)

Shielded Metal Arc Welding (SMAW) also known as Manual Metal Arc Welding (MMAW), is a manual arc welding process that uses a consumable electrode (covered with a flux). Electrode is connected with one terminal of the power source and the work is connected with the other terminal of the power source. Welding cable (or lead) is used for this purpose. The power source can be used in AC (alternating current) or DC (Direct current). In….

Welding electrodes – Understanding the SMAW electrode symbols

Shielded Metal Arc Welding (SMAW) electrodes are designated by “E” followed by four (or five) digits for example: E7018, E6013 or E10018. I will explain the meaning of these symbols: IF THE ELECTRODE HAS “E” FOLLOWED BY FOUR DIGITS (FOR EX. E7018) E – Stands for electrode XX – First two digits designates the minimum tensile strength in Ksi (XX * 1000 Psi) X – Second last digit designates position….

Types Of Welding – Classification of welding processes

Welding is a process of permanently joining two or more parts by the application of heat and (or) pressure. As per American Welding Society 50 different welding processes available today; some are very popular among the industries such as SMAW, GMAW, GTAW, SAW, FCAW etc. whereas some are very specific and limited to few industries such as USW, RSW, DW etc. Welding processes are broadly classified as fusion welding and….

Dye Penetrant Test (DPT, LPI, PT) – Non Destructive Test

Dye Penetrant Test (DPT) is also known as Liquid Penetrant Inspection (LPI) or Penetrant Test (PT). It is one of the most widely used Non Destructive Test (NDT) methods. It can be used to inspect almost all non-porous materials such as metals, plastics, ceramics etc. We can detect any surface discontinuity (or flaw) such as surface cracks, porosity, pinholes etc. by this test method. Principle: DPT is based upon a natural….

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