How to calculate heat input

Heat input is a critical parameter for arc welding processes. The Heat input shall be controlled to ensure sound weld quality. Heat input may be defined as “The amount of electrical energy that is supplied to a weld during the welding process”. How to calculate Heat input? There are several ways of calculating the heat input. We shall discuss the two most common methods of calculating the heat input. 1…..

Plasma Arc Welding (PAW)

Plasma arc welding (PAW) is an arc welding process in which the heat required for welding is generated by a constricted arc between a non-consumable electrode and the workpiece. Plasma Arc Welding is essentially an extension of Gas Tungsten Arc Welding (GTAW). Like GTAW, a non-consumable electrode is used in Plasma Arc Welding (PAW). However, a different technique is used to deliver the heat for welding in Plasma Arc Welding….

Acceptance Criteria for Weld Defects

Acceptance criteria for Visual Inspection (Refer: UIG-97, Page – 345 of of ASME BPVC Section VIII Div 1, 2017 Edition.) (a) The surface shall be free of any visible laminations, spalling, or cracks. Cracks in tubes shall not be repaired and shall be considered cause for rejection. (b) For tubes, scratches shall not exceed 1/32 in. (0.8 mm) in depth. For all other material, scratch depth shall not exceed 1/8….

Summary of ASME BPVC Section IX – Part 3

In part – 1 of this article, we had discussed the general requirements as mentioned in part QG of ASME Section IX, To read that article please click here. In part – 2 of this article we had discussed about the weld orientations, test positions for groove, fillet and stud welding etc. as mentioned in Part QW of ASME Setion IX. To read that article please click here. In the….

Summary of ASME BPVC Section IX – Part 2

In part – 1 of this article, we had discussed about the general requirements as mentioned in part QG of ASME BPVC Section IX. To read part – 1 of this article please click here. This article will cover the Part QW of ASME section IX, which is dedicated to the general requirements in the welding. Part QW is further divided into five articles, these are; Article 1. General requirements for….

Summary of ASME BPVC Section IX – Part 1

ASME Boiler and Pressure Vessel Code (BPVC), Section IX contains qualification standard for the following; Welding, Brazing and Fusing procedures Welders and welding operators Brazers and brazing operators Plastic fusing operators Section IX is a reference document for the qualification of material joining (welding, brazing and plastic fusing) processes, used by various construction codes such as Section I, III, IV, VIII, XII, etc. NOTE: The different material joining processes covered….

Magnetic Particle Testing

Magnetic Particle Testing (MT) (also known as magnetic particle inspection – MPI) is a non destructive test (NDT) method, used to detect surface or subsurface (near to surface) discontinuities. This NDT method can be used on metals which can be easily magnetized (ferromagnetic). Metals can be classified as ferromagnetic, paramagnetic, or diamagnetic. Ferromagnetic metals: Ferromagnetic metals are those, which are strongly attracted to a magnet and can be easily magnetized…..

(OFW) Oxy-Fuel Welding (Gas Welding/Oxy-Acetylene Welding)

Oxy-fuel welding (OFW) is also known as Gas welding or Oxy-fuel gas welding. The term ‘Oxy-fuel’ is used to denote a combination of Oxygen and a Fuel gas, means it’s a process in which Oxygen and a fuel (combustible gas) both are required. Most commonly used fuel gas is Acetylene and thus the name Oxy-Acetylene welding (OAW) is also used for this process, when Acetylene is used as a fuel….

Thickness range for welder qualification and procedure qualification (ASME Section IX)

Thickness range for performance qualification (welder qualification test): ASME BPVC section IX has provided guidelines for the thickness range up to which a welder can weld. This can be found in Table – QW 452.1(b) of ASME BPVC Section IX (2017 edition). A simplified version of that table is given below; According to this table three important points can be drawn: The maximum thickness which a welder can weld is….

P Number, F Number and A Number in welding (ASME Section IX)

ASME Boiler and pressure vessel code (BPVC) has assigned certain numbers to base metals as well as to filler metals (electrodes). For base metals, ASME has assigned two number system, these are; P Numbers Group Numbers For filler metals, the number system which are assigned, are as follows; F Number A Number These numbers can be found in ASME BPVC Section IX (2017 edition), please see table – 1 for….

Preheating – How, When and Why

Heating the base metal to a specific desired temperature before welding is called as preheating. The temperature at which the base metal is heated is called as the preheat temperature. Preheat temperature can be determined by the applicable code. Please see table 1 to know how to find the preheat temperature in the respective code: In absence of code, the following factors shall be considered for determining the preheat temperature;….

(SAW) Submerged Arc Welding

Submerged Arc Welding (SAW) is an arc welding process in which arc is generated between a bare electrode and the workpiece. The arc and the molten weld pool are submerged in a blanket of granular fusible flux on the workpiece. Flux covers the arc and prevents fumes, sparks, spatter, and intense ultra violet radiation from escaping, which makes this process very different from other arc welding processes. Submerged arc welding….

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