Table of Contents
Welding Metals – An Introduction
To join ferrous with non-ferrous metals, various methods can be adopted.
Welding is the most commonly used process of all.
Welding – A Definition
Welding can be described as a process of joining two or more pieces /edges of metal by producing a localized union through heat (fusion) with or without pressure to create a homogenous joint.
Types of Welding by Metal:
Autogenous: In this process, similar materials are joined without filler wire or electrode
Heterogeneous: Process of joining dissimilar materials, using a filler wire or welding electrode
Types of Welding by Method:
1. Fusion Welding (Electrical Energy):
2. Solid-State and other Non-electric Fusion Welding: Examples of non-fusion, non-electric process welding are:-
Solid State welding:
DEFORMATION WELDING: Two Surfaces in contact are brought into very close contact by applying high pressure, which deforms them. E.g., – Forge welding, Roll welding, Extrusion welding. (Not at very high temperatures)
DIFFUSION WELDING: Joining takes place by atomic diffusion of 2 surfaces in contact. Surfaces are usually heated to high temperatures (below the melting point) & pressure may be employed. E.g., Brazing, Braze welding & Soldering. Soldering is an oxy-fuel process of joining metals. The process temperature does not exceed 450⁰. Brazing is also an Oxy-Fuel joining process. The process temperature is between 450⁰ Degrees – 750⁰ degrees. Braze welding is similar to Brazing; the process temperature is above 750⁰ Degrees but below the melting point of the base metal.
Non-Fusion Process: Thermit welding is the most common process used in joining of railway tracks. In this process iron powders and Al binders are kept in Vat or a conical container above the joining rails. When they are fired due to chemical reaction and exothermic reaction, the iron powder melts and forms a joint between rails.
Introduction to Arc Welding: Basic welding processes used in Industry are
MMAW or SMAW- Shielded Metal Arc process: In the Shielded Metal Arc process or Manual metal Arc welding process the arc is established between Parent Metal and a flux coated welding electrode using electrical energy to melt and deposit weld metal. This is the most commonly used process in the world.
Basic Requirements for the SMAW process:
Heat source: Welding Equipment Current Range 30-400 A –depending on size of the electrode in general, even though there are welding machines used up to 600 Amps AC or DC welding machines can be used in SMAW Operation.
Welding Consumable: Flux coated welding electrode (1.6- 8 mm diameter)
A trained welder is required to operate the process, So SMAW or MMAW is the most commonly used process in the world.
SMAW Process advantages:
Limitations of SMAW process:
GMAW & FCAW processes:
GMAW uses solid wire, no flux
FCAW use flux-filled wire
Advantages in GMAW:
Limitation in GMAW:
More Complex due to
GTAW or TIG welding: GTAW or Tungsten Inert gas welding uses a consumable Tungsten electrode as the heat source.
This consists of the below.
Heat source – welding power source to create an arc between a tungsten tip and the parent metal
30-400A, AC or DC welding machine and 0-20V
Inert gas shielding is used in the process.
Consumable: filler rod can be used between 1 to 4mm diameter
Advantages in GTAW/TIG Process:
Limitations in GTAW:
Submerged Arc welding process (SAW Process): In the Saw Process, as the name signifies, welding happens submerged beneath the flux. SAW process also employs welding consumables usually a wire & arc is established between the welding wire and base metal and welding happens underneath the metal powder of flux, shielding the arc from the atmosphere and its gases.
Heat source: Arc between a wire and base metal
Current Range: 200 Amps -1200 Amps
Hence the basic difference between the two processes is that in the SMAW process, the flux-coated electrode provides the shielding from the atmosphere & in SAW process an external flux is delivered at the arcing area to act as a shield, so welding happens underneath the powder flux fed by a delivery system.
SMAW Process – Advantages:
SAW Process advantages:
Limitations of the SAW process:
Conclusion: A wide variety of processes are available for joining or hard surfacing ferrous and non-ferrous materials. Each of these processes provides different mechanical properties and works in specific conditions, with a welding power source. There are several factors to consider in welding rod selection:
These methods are all commonly used by Industry. Before we select any particular method for welding, we need to analyze each of the factors listed above.
ADFL serves the industry with the manufacture and supply of all types of consumables for MMAW, MIG /Mag, TIG, SAW & non-fusion processes like soldering, brazing, and braze welding. This is why Ador Fontech’s name is synonymous with total solutions for any maintenance & repair problem, ensuring the Life Enhancement of Industrial components, to the complete satisfaction of customers.
Reclaim, do not Replace
For more information Thermite Welding Equipment, please get in touch with us!
Auto Feeding Manual Screwdrivers hydraulic shearing machine what does a die cutting machine do drilling pipes for sale Cannabis weighing machine Gas Pressure Sintering Furnace DTH Drilling Rig Water Well Drill Rig best plasma cutter IGBT Inverter Series ADVAN CUT 40 Safety Valve Grinder Supplier Water Distribution System Pipe-Steeltube machines Bulk, Cryogenic Storage Tank Low Speed In-Line Plastic Grinder Granulators Separated Coatings Aluminium Production Line