Difference between Welding, Brazing and Soldering

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Difference between Welding, Brazing and Soldering

Posted on by adorfon

Table of Contents

  • Principle of Welding Processes
  • Principle of Brazing and Soldering Process
  • Welding / Shielded Metal Arc process (SMAW)
  • Basic Requirements for Welding / SMAW process
  • Welding Process Advantages
  • Limitations of Welding Process
  • Soldering & Brazing
  • Four Requirements of Non-Fusion Welding
  • Advantages of Non-Fusion –Brazing and Soldering Process
  • Dis-advantages of Non-Fusion – Brazing and Soldering Process

To understand the basic difference between the three processes namely welding, brazing & soldering, we need to know about types of welding processes by principle.

Principle of Welding Processes:

  • Fusion welding
    • Welding done in liquid state without using pressure
    • Union is by molten metal bridging of mating surfaces

Principle of Brazing and soldering Process:

  • Solid phase welding
    • Welding done below the melting point without any filler additions
    • Pressure is often used in this type of welding
    • Union often occurs when material is in plastic flow

The Welding process is a Fusion process where as brazing and soldering are both solid phase welding processes.

Let us understand more about these three processes, which are widely used by many industries.

Welding / Shielded Metal Arc process (SMAW):

Shielded Metal Arc process is also known as manual metal arc welding process. In this process, an arc gets established between parent metal and a flux coated welding electrode using electrical energy. This arc melts the deposit weld metal and nn this process, actual melting of base metal and welding electrode bridges the gap and forms the welding This process is one of the most used welding processes in the world.

Basic Requirements for Welding / SMAW process:

Heat source – Welding Equipment Current Range 30-400 A –depending on size of electrode in general, even though welding machines  that use up to 600 Amps AC as well as DC welding machines are equally useful in a SMAW Operation.

Welding Consumable: Flux coated welding electrodes (1.6- 8 mm diameter) are needed for the process along with a welder who is trained to manage the welding.

SMAW or MMAW is a commonly used welding process in the world.

Welding Process advantages:

  • Simplest of all welding processes
  • The equipment used is portable
  • Cost of equipment is economic
  • It has a variety of applications
  • There’s wide availability of electrodes
  • Can weld a wide range of metals & their alloys
  • Welding can be done from any position
  • Welding can be done indoors & outdoors
  • Welding cable extension goes very far

Limitations of welding process:

  • Low productivity as in a 10-minute cycle, welding happens only for 6 minutes
  • Process also involves frequent change of welding electrode
  • Moisture from flux coatings can create weld-related problems
  • Safety issues with arc strike, shocks from stray current/electric power
  • Process is completely manual as the name ‘Manual metal arc welding’ suggests

Soldering & Brazing:

In both the above processes joining  happens by diffusion welding methodology, The joining happens through atomic diffusion of two surfaces in contact. Surfaces are usually heated to high temperature (below their melting point) & pressure may also be employed.

  • Soldering: Soldering as a process happens below 450 degrees Celsius Normally lead or tin based alloys are used for soldering
  • Brazing: This process happens between 450 degrees and 750 Degrees Celsius Silver & copper-based alloys are used for brazing.

Four Requirements of Non-Fusion Welding

  1. Clean Surface: Non-fusion processes bond metal by adhesion, where adhesion happens to be the molecular attraction between bodies in contact.
  • Molecular bonding requires a clean surface.
  1. Filler Rod:
  • Filler rods are used in many non-fusion processes.
  • Brazing:
    1. Brazing rods can be bare rods or flux coated.

    Soldering:

    1. Solder can be solid or flux core/paste
    2. Can be tin, silver or zinc alloy
    3. Promotes wetting
  1. Flux :

Flux has applications in all non-fusion welding processes.

Purpose of flux:

  1. Chemically cleans the metal
  2. Shields weld from oxidation and atmospheric contamination
  1. Heat Source

The heat must be sufficient (BTU”s) to raise the base metal temperature above the melting point of the filler rod.

To achieve this, several heat sources can be used.

  1. Oxyacetylene
  2. Air acetylene
  3. Air propane (LPG)
  4. Oxypropane
  5. Electric soldering iron
  6. Electric soldering gun

Advantages of Non-Fusion –Brazing and Soldering Process:

  • Lower temperature process
  • Easy assembly of parts
  • Welding dissimilar metals
  • Allows disassembly/realignment
  • Joins metals of different thicknesses
  • Joint different types of metal

Dis-advantages of Non-Fusion – Brazing and Soldering Process:

  • Lower tensile strength
  • Not an efficient method for thick metal
  • Not an efficient method for large parts.

So, the essential difference between Welding, Soldering & Brazing is as below.

  1. Welding is a fusion process, where there is a homogenous bonding of joining surfaces.
  2. While brazing and soldering are basically non-fusion processes which use diffusion to join materials.

All three processes have a wide variety of applications in industries depending on the uses and requirements. ADFL serves the industry with manufacture and supply of products in all three processes.

Repair – Do not replace

welding brazing and soldering

Tips for Welding Austenitic Stainless Steel

Posted on by adorfon

Table of Contents

  • Properties of Stainless Steel
  • Types of Stainless Steel Used in Industry
  • Problems in Welding Austenitic SS
  • Carbide Precipitation or Inter Granular Corrosion
  • Remedies: Do’s for Welding Austenitic Stainless Steel

Stainless steel is the type of high alloy steel with at least 11.5% Chromium. Iron content exceeds that of any other element. Carbon is generally less than 1.5%.

Properties of Stainless Steel:

    • Mechanical Properties: Compared to other materials, stainless steel has strong mechanical properties at ambient temperatures, In particular, it combines ductility, elasticity, and hardness, In addition, it offers good mechanical behavior at both low and high temperatures. So widely used in all Industries.
    • Oxidation Resistance: Stainless steel has the best resistance of all metallic materials when used in structural applications, having a critical temperature above 800°C. Grades of Stainless steel can be used for Sub-zero temperatures.
    • Corrosion Resistance: With a minimum chromium content of 10.5%, stainless steel is continuously protected by a passive chromium oxide layer, This special feature gives stainless steel its resistance to corrosion.
    • Versatility: Stainless steel has a wide variety of finishes, from matte to bright, including brushed and engraved. It is widely used by architects for building envelopes, interior design, and street furniture.
    • Easy Maintenance: Stainless steel objects are easy to clean, and common cleaning agents.
    • Environment friendly: Stainless steel is the “green material” and is infinitely recyclable. It is environmentally neutral and inert when in contact with elements like water, and it does not release compounds that could change their composition.

Types of Stainless Steel Used in Industry:

  • Austenitic  Non-Magnetic & work Hardening 
  • Ferritic Soft & Magnetic 
  • Martensitic  Magnetic & Hard
  • Duplex Magnetic & Wok Hardening 
  • Precipitation Hardening

Problems in Welding Austenitic SS:

  • Carbide Precipitation or IGC 
  • Heat of Welding 
  • Porosity
  • Contamination

Carbide Precipitation or Inter Granular Corrosion:

The major problem encountered in welding austenitic stainless steel is intergranular corrosion or carbide precipitation.

  • When welding Austenitic SS  between 420 to 880 deg. C base metal temperature also known as “Sensitisation Temperature”  a large volume of Cr is picked  in the grain Boundaries of the HAZ area
  • This forms Chromium Carbide which precipitates and forms at grain boundaries –the area adjacent to the HAZ area
  • So on working condition or in service, the HAZ area starts corroding at a faster rate as this area cannot form Cr2O3 due to Cr depletion 
  • This phenomenon is called Inter Granular Corrosion or Carbide Precipitation

Remedies:

  • Controlling the carbon content (0.03% or below)
  • Addition of Carbide stabilizers like Ti, Nb.
  • Heat Treatment (Solution annealing).
  • Controlled welding below 450 Degrees 

The heat of welding:

  • Cracking from the HAZ area
  • Loss of Corrosion Resistance 
  • Warping or Distortion of Material 
  • Loss of Mechanical Properties 

Porosity :

  • This is caused by Dirt, Grease & marking material 
  • Poor Quality of Flux coating 

Contamination:

  • Contaminants in SS like Sulphur, Carbon, Iron, Copper & lead is the root Couse of failure of welded joints and also poor corrosion resistance 

 Remedies: Do’s for Welding Austenitic Stainless Steel: 

  • Rigid Fixturing with more tack welds
  • Sequence welding to control heat 
  • Baking of electrode 200 deg –one hour before welding.
  • Proper Cleaning of weld area before starting the job 
  • Use short arc & low heat Input Welding Electrodes 
  • Use Correct or optimum diameter electrode during welding 
  • Clean slag after every pass / between passes.

Hence with these simple strategies, we can weld all applications of austenitic stainless steel.

We at Ador Fontech have designed & developed this exclusive range of LH- Low heat Input Welding Electrodes, TIG & MIG wires for welding of all types of stainless including austenitic stainless steels.

Reclaim, Do not replace

 

Welding Equipment in Industry

Posted on by adorfon

Table of Contents

  • MMAW / Arc Welding Equipment – Features
  • MMAW / Arc Welding Equipment – Advantages
  • Types of Arc Welding Equipment / Power Sources
    • Motor Generator
    • Welding Rectifier
    • Welding Inverter

In fabrication, welding helps to join materials using heat to melt the parts together. Useful with metals and thermoplastics, this process typically uses a filler material to the weld pool of molten material, helping to make the joint stronger than the base material. Pressure is used in the process along with heat in welding, while a shield protects the metals from being oxidized in the process.

The most heat sources for joining material using a fusion welding process are listed below:

Fusion welding sources

We have five types of Arc welding Equipment/power sources. These are AC transformer; DC rectifier; AC/DC transformer rectifier, DC generator, and inverter.

MMAW / Arc Welding Equipment – Features

  • Portable & Versatile equipment
  • Requires practiced skills
  • Applicable to a wide range of materials, joints, positions
  • About 1kg per hour of weld deposited
  • Properties can be excellent
  • Benchmark process

MMAW / Arc Welding Equipment – Advantages

  • This is the simplest of all Arc welding processes.
  • Equipment is portable
  • Economical Cost of Equipment
  • Variety of applications & wide availability of electrodes
  • The range of metals & their alloys can be welded
  • Welding in all Positions
  • Welding can be Indoors or Outdoors 
  • Welding cable can be extended to long distances when compared to other processes

Types of Arc Welding Equipment / Power Sources:

Arc welding power sources

A welding transformer is basically a step-down transformer that brings down the source voltage to weldable voltage. This is simple Arc welding Equipment.

Motor Generator 

Motor Generator is also an Arc welding Equipment, which utilizes input power to rotate the generator through an induction motor. This kinetic energy is converted to electrical energy by carbon brushes fitted in the commuter, generating DC current is generated supplying constant power to the process.

In a Diesel Generator, diesel is used as fuel to run the motor to generate electricity; this is widely used in on-site jobs for Arc welding applications 

Welding Rectifier

Welding rectifiers are essentially transformers with an electrical device as a rectifier which changes AC to DC. Rectifier basically consists of Silicon diodes, which ensure the flow of current in one direction giving DC output. This is most commonly used with Arc welding equipment.

Welding Inverter

This latest technology power source is the most popular Arc Welding equipment today. A welding inverter is a power block, controlled by software, which offers the required static and dynamic characteristics needed for a specific welding process. It takes AC input and converts it into DC after step-down & then converts it further into high-frequency AC & then again converts it to DC – finally offering a DC output. When using an inverter power source, a user gains all the advantages of thyristor control. Additionally, they get superior efficiency, power savings, better performance, and quality of welding.

We at Ador Fontech offer the best “Make in India” solutions with Fontech Tornado brand Welding Power sources. We offer both robust Thyristor-controlled machines as well as Power saving Inverter machines for all welding processes like Manual Metal Arc welding, TIG, MIG/MAG, and SAW. Once again, we reiterate our total commitment to total solutions in welding with this range of equipment, catering to the complete requirements of customers. 

Reclaim. Do not Replace.

 

Also read:- Hypertherm Life Expectancy of Consumables

Key Differences Between SMAW and SAW Welding

Posted on by adorfon

Table of Contents

  • An Introduction to Shielded Metal Arc Welding (SMAW) process
    • Heat source
    • Energy Consumption
  • An Introduction to Submerged Arc Welding (SAW) process
  • Advantages with the SMAW Process
  • Limitations of the SMAW process
  • Advantages with the SAW Process
  • Limitations of the SAW process

The basic difference between the two processes, SMAW and SAW welding, is this. In the SMAW process, the flux-coated electrode helps to shield the welding process from any interaction with the atmosphere. In the SAW process, an external flux delivered at the arcing area acts as a shield. So, the welding happens underneath the powder flux fed by a delivery system. This is the primary difference between SAW & SMAW processes. Let us get introduced to both processes.

Pic SAW SMAW

An Introduction to Shielded Metal Arc Welding (SMAW) process

In SMAW or MMAW (Manual Metal Arc Welding), the arc is established between Parent Metal shielded (flux-coated) welding electrodes using electrical energy to deposit weld metal. 

Heat source: Arc between metal and a flux-coated electrode (1.6- 8 mm diameter)   

Energy Consumption: 30 – 400 Amps –depending on the size of the electrode in general, even though there are welding machines that use up to 600 Amps. AC or DC SMAW Operation Power consumption 1-12 KW

An Introduction to Submerged Arc Welding (SAW) process

 In the SAW Process, as the name signifies, the welding happens submerged beneath the flux. SAW process also employs a welding consumable, usually a wire. An arc is established between the welding wire and base metal and welding happens underneath the metal powder of flux, which shields the arc from the atmosphere.

image

Heat source: Arc between a wire and base metal 

Current Range: 200 Amps -1200 Amps

DC operation                       

Power Consumption-35-56 KVA

  • Power source
  • Welding head and control box
  • Welding head travel
  • Flux recovery system (optional)

Let us take a look at the process advantages & limitations of both SMAW and SAW processes.

Advantages with the SMAW Process:

  • This is the simplest of all Arc welding processes.
  • Equipment is portable
  • Cost of equipment is economical
  • Variety of applications & wide range of electrodes available
  • A range of metals & their alloys can be welded
  • Welding can be done in all positions
  • Welding can happen indoors & outdoors 
  • Welding cable can be extended to long distances in comparison to the SAW process

Limitations of the SMAW process:

  • Low productivity as in a 10-minute span, welding happens only for 6 minutes 
  • The process also involves the frequent change of welding electrode
  • Moisture from flux coatings can create weld-related problems
  • Safety problems like arc strike, stray current & electric shock risks
  • Absolutely manual process – hence called Manual Metal Arc Welding 

Advantages with the SAW Process:

  • High productivity up to 2 to 10 kg per hour.
  • Speed almost up to 2m/min
  • Can be easily automated for even higher productivity.

Limitations of the SAW process:

  • Bulky, expensive, and heavy equipment
  • Flat and horizontal positions only
  • Thicker sections (6mm and above)
  • Mostly ferrous materials (also Ni alloys)

Given these essential differences between MMAW/SMAW and SAW processes and their respective advantages and limitations, a considered choice can be made between these processes.

image

We, at Ador Fontech, offer the best “Make in India” solutions with Fontech Tornado brand welding machines for both SMAW and SAW processes. Once again, we reiterate our commitment to total solutions in welding to the complete satisfaction of customers, with this range of equipment.  

 

Also read:- Resolve Wear Factors