Brazing vs Welding – Find the Difference

If you want to make a permanent joint between 2 or more metals, there are various ways to accomplish project. Anyhow, welding and brazing are most common and most reliable solutions available.

Both are individual metal-joining sheet metal techniques within the overall sheet metal fabrication process, but each operation differs to some extent.

Shortly, welding is a technique that joins metals by melting the base metal and causing fusion, while brazing joins metals by melting and flowing a filler metal into the joint.

However, while brazing and welding both allow for the permanent joining of 2 metal surfaces, they practice in different ways.

Below is a comparison between brazing and welding, showing how these typical metal-joining methods differ.

What is Brazing

Brazing implies to a group of joining processes that produce the coalition of materials by heating them to the brazing temp using a brazing filler with a liquidus above 840°F and without melting of the base metal.

The melting point is the lowest temperature at which a metal or an alloy is absolutely liquid, and the solidus is the highest temperature at which a metal or an alloy is entirely solid. Brazing transfers a brazing filler metal between the closely fitted faying surfaces of the joint.

With the application of heat, the brazing filler metal flows by capillary action, while is melted and re-solidified to create a metallurgical bond among the surfaces at the joint. Brazing includes applications such as electrical, electronics, automotive, aerospace, construction, and HVAC.
Brazing also enables an essential advantage in applications that need joining of different base metals, like steel and copper along with non-metals like a diamond, tungsten carbide, and graphite.

Brazing Equipment

  • Torch, furnace, heated chemical bath or inductor coil for melting filler metal;
  • Flux solution or a filler material such as fluorides, chlorides, borates, fluoroborates, and alkalis;
  • Safety equipment including safety glasses and thick work gloves.

Brazing Methods

These are the most commonly used brazing methods:

  • Torch brazing uses oxyfuel gas like acetylene, propane or even gas torch and a city gas;
  • Furnace brazing involves preloaded parts with filler metals and flux placed in a furnace. This process is commonly exploited in factories for automated production;
  • Dip brazing involves a heated chemical bath which is both the heat source and the fluxing agent. Pre-assembled parts with pre-used filler material are immersed in the bath. This method is usually applied with aluminum assemblies;
  • Induction brazing uses clamps or tongs for holding the metal pieces to inductor coils to produce an electrical current around a pre-fluxed, pre-assembled part that has been preloaded with filler material. This technique is exploited when a portion of the assembly would be adversely affected by heat induction while allowing selectively heating of the metal piece by the coil.

Brazing Advantages

  • Does not need melting the base metal;
  • Able to join different metals and non-metals together;
  • Cost effective for multi-part and complex assemblies;
  • Makes a clean joint without the need for secondary processing.

Brazing Disadvantages

  • Unable to join large sections;
  • The strength of the joint or seam is not as strong as a welded one;
  • Brazed joints can be damaged by high temperatures;
  • The joint color is usually a different color than the base metal;
  • Filler and fluxes materials can contain toxic components.

What is Welding

Welding is a fabrication that joins metals by melting and fusing them together with the adding of a welding filler metal. The joints created are strong, commonly strong as the metals joined, and in some cases even stronger.
To fuse the metals, use a concentrated heat directly to the joint surface. This heat should apply high temperature to melt the filler metals and the base metals.

Welding is as a rule suited to joining large assemblies where both metal portions are quite thick (0.5”) and joined at a single point. Because the bead of a welded joint is uneven, it’s not generally applied in products requiring cosmetic joints.

Applications made from welding include construction, transportation, fabricating, and repair shops. There are many examples for welding applications such as building structures, fabrication of pressure vessels, robotic assemblies, pipelines, ships, railway, aircraft, railway tracks, and coaches.

Welding Equipment

  • Welding torch;
  • Fuel gas cylinder;
  • Oxygen cylinder;
  • Electricity source;
  • Protective gear;

Welding Methods

Some of the most critical welding methods are:

  • Fusion welding: In this type of welding, the material at the joint is heated to a molten state and allowed to solidify;
  • Pressure welding: In this technique, the piece of metal to be joined is heated to a plastic form and then fused together through external pressure;
  • Arc welding: It’s the most extensively used welding process. In this kind of welding, the source of heat is an electric arc which is made by the electrode connected to the power supply;
  • Friction welding: This method is solid state welding which produces a coalition of material by the heat generated from a mechanically induced sliding motion between the rubbing surfaces of the 2 cylindrical workpieces under pressure.

Welding Advantages

  • Cost effective;
  • Tight and strong quality joints;
  • Able to join large sections;
  • Residue removal isn’t required in some applications.

Welding Disadvantages

  • The process can have harmful effects such as high temperatures, blinding light, toxic fumes, and radiation;
  • Changes in the properties of the base metal structure can result in internal stresses or distortion in the weld area;
  • Not suitable for some thin metals.

Welding vs Brazing

Welding and brazing are 2 types of methods that are used for joining different metal parts. These 2 processes are also applied to join or fix broken pieces or to fill the gaps in metals.

Although these 2 methods have the same use, they have different mechanisms. They are different in the utilization of temperature and melting of base/filler metals.

Welding is exploited for joining metal pieces along with thermoplastics. It is a method in which the base metal and the filler metal are melted, and each makes a weld pool or a molten material. This weld pool solidifies to produce a solid joint.

As opposed to welding, only the filler metal is melted in the brazing process. The filler metal is melted between the parts that need to be joined. Therefore, the wetting produced between the joints becomes solidified and provides to joint more strength.
So, you can conclude that welding melts the filler and the base metal, while brazing melts only the filler metal.
For brazing, the parts of the 2 metals that have to be joined must be free from oxides. In brazing, the metals that are going to be joined together aren’t heated to their melting points, since only the filler metal is heated just above the melting point.

An obvious difference between brazing and welding is in the temperature. In welding, a high temperature is required. While in brazing, the temperature is slightly lower than the temperature applied in welding.

Brazing vs Welding Strength

Consider welding when you want much more reliable and permanent metal-to-metal joints. Brazed joints have different properties than welded joints such as strength, resistance to leak-tightness, vibration, and shock.

Brazing provides permanent bonds, but generally, welding can offer the strength of a welded joint, equivalent to or greater than the base metals themselves. Nor brazing is able to produce joints that resist temperatures above 1630°F.

Brazing vs Welding vs Soldering

Brazing, welding, and soldering are all processes of joining two or more pieces of metal and other materials. These all are joining methods, but different way uses in different conditions.
Welding is used in mechanical industries for joining the same or different metals. The leading role of welding is to produce a strong joint which can carry all mechanical stresses.

Soldering is used in electronics and electric industries. It is used to join wire to panel. The primary function to these processes to make an electrically strong joint which can withstand in any electrical condition.

Brazing is using dissimilar joint metal in aircraft and automobile industries. Brazing joints are weaker than welding joints but stronger than soldering joints.

Braze Welding

The braze welding process is a version of the MAG/MIG welding method, where the vast of the method-essential elements are equivalent to traditional MAG/MIG processes.

Still, in the braze welding, the melting point of the filler wires is significantly lower with the relation to the melting point of the parent material.
During the arc welding process, the filler wire melts at temperatures typically over 2900°F, while for brazing the wire melts at less than 1830 °F.

The braze welding process is considered as an excellent solution for the joining of galvanized thin sheet steels. These steels, when welded by a conventional arc-welding method make large amounts of zinc vapor.

The welding method also applies significant heat into the base metal, resulting in a wide heat-affected zone and considerable distortion. These effects can be minimizing by using a brazing technique since the lower heat is needed to melt the filler wires compared to a traditional welding method.