Have you ever wondered how to join two metals but were stuck between brazing or welding? This article will help you understand the differences between brazing and welding to decide which method suits your project. Prepare yourself for some hot insight!
Both brazing and welding join metals but differ in temperature, the process, and the filler used. Brazing is melting and flowing a filler material with a lower melt point than the workpieces over the joint. Welding involves melting the workpieces and adding filler metals to the joint.
Do you need help determining which method will work best for your project or business? Continue reading. You can make the best decision if you know some information that will help.
Understanding Brazing VS Welding
What is brazing?
We join metal by brazing. It’s a flexible way to join metals that are different or similar. Brazing, unlike welding, does not melt base metals. It involves melting a metal filler into the joint.
The Brazing Process: Step-by-Step Guide
- Prepare the Metal Surfaces： The first step to brazing involves preparing the metal surface. Cleaning the metal surfaces is necessary to remove oxides, grease, or other contaminants. Surface preparation is essential to ensure the filler metal adheres well to the base metals.
- Fitting & Fixturing: The parts to be connected must fit tightly together. Usually, the gap between them is 0.05mm – 0.1mm. The close fit is essential for capillary action, which draws the molten metal filler into the joint.
- Filler Metal: A suitable filler metal will ensure a successful brazing process. The filler metal must have a melting point lower than the base metals and should be compatible regarding thermal conductivity and thermal expansion.
- Flux Application: You should apply flux to the joint before heating it. Flux prevents oxidation during the heating of base and filler materials and increases the flow of filler metals by reducing the surface tension.
- Heating: Heat the assembly until the filler metal melts, not the base metals. Depending on the project’s requirements, you can use different heating methods. These include torch brazing and furnace brazing.
- Capillary Act: The filler metal melts, and capillary action pulls it into the joint to fill the gap between the base materials.
- Cooling： Once the filler metal has been drawn into the joint and the assembly cools, remove the flux and oxidation residues. This leaves behind a neat, strong joint.
What is welding?
By causing coalescence, welding joins materials (usually metals or thermoplastics). The weld pool is formed by melting the metals, adding filler materials, and cooling them to create a pool of molten metal.
The Welding Process – A Step-by-step Guide
- Safety Measures： Before welding, you must take the necessary safety precautions. Wearing protective gear like gloves, safety lenses, and a helmet for welding is essential to protect against heat, sparks, and harmful radiation.
- Prepare the Metal Surfaces: Welding requires a clean surface to ensure a good bond. You should clean the area to be welded and ensure it is free of rust, paints, oils, and other contaminants. This could involve chemical or mechanical cleaning, such as sandblasting or grinding.
- Selecting the Welding Process There are many welding processes, such as MIG (Metal Inert gas), TIG(Tungsten Inert Gas), SMAW(Shielded Metal Arc Welding), etc. The selection depends on the welded material, desired strength, and project requirements.
- Setting up the Equipment： After selecting the welding method, you must set the equipment up according to the manufacturer’s instructions. Adjust the power supply and gas flow for gas-shielded welding processes, and choose the correct welding rod or wire.
- Joining: An electric arc is created between the electrode wire and the workpiece to weld the joint. (Or the filler wire melts with the workpiece when MIG welding) This arc melts the edges of the base material and the filler to form a pool. To ensure a consistent and robust weld, the welder must carefully control the arc, travel speed, and filler material.
- Inspection and Cleaning： After welding, cleaning the area around the weld and removing slag or other residues is often necessary. Inspect the weld visually and conduct other tests, such as ultrasonic or X-ray, to ensure it meets all standards and specifications.
Brazing VS Welding: Key Components
The Key Components in Brazing
The success of any brazing operation depends on selecting and applying several vital components. Understanding these components is essential for creating robust and reliable joints.
Filler Metals & Fluxes: Brazing Materials
- Filler Materials: When brazing, the choice of filler material is crucial. It must be compatible in terms of melting points and alloy compatibility. Silver, copper, aluminum, gold, and their alloys are common filler metals. Each metal has its properties and uses. Silver alloys, for example, are used in plumbing and electrical applications because of their high conductivity and strength.
- Fluxes: Flux prevents oxidation during the heating of base and filler materials. Flux also cleans the metal surfaces and ensures the filler metal adheres correctly. The type of flux to use depends on the base metals used and the brazing conditions. Borax-based fluxes are the most common, but you can also find fluxes for metals such as stainless steel or aluminum.
Heat Sources for Brazing
The brazing method is chosen based on the joining materials, the filler metals, the flux, and the requirements of the joint.
- Torch brazing: This method uses a gas flame to heat metal parts. It’s suitable for smaller production quantities or specialized applications. It is ideal for complex assemblies because it offers flexibility and control.
- Furnace brazing： This method is preferred for larger quantities to achieve consistent results. The assembly is placed in the furnace and heated uniformly. This method is automated and used in mass production.
- Induction-Brazing: By using electromagnetic fields to produce heat, induction-brazing heats metal parts quickly and accurately. This method is highly effective for specific applications, such as joining cables or pipes.
- Resistance brazing: This technique uses electrical resistance to create heat directly in the joint area. This method is beneficial for joining small parts or when you need precise control over the heating zone.
The Key Components in Welding
You can use many different welding techniques and materials for various applications and metals. Understanding key components such as welding methods and materials is essential for achieving the best results.
Welding methods: MIG TIG Stick and More
- MIG Welding: MIG welding, also known as Gas Metal Arc Welding or GMAW, is a versatile technique that uses a continuously fed wire as an electrode. A shielding gas protects the weld pool against contamination. It is fast and efficient and can be used to weld mild steel, stainless steel, and aluminum in various thicknesses.
- TIG Welding: TIG Welding, also known as Gas Tungsten Arc Welding or GTAW, uses a non-consumable electrolyte to create the weld. If you use filler metal, add it separately to the weld pool. This method is high-precision and suitable for thin materials or demanding applications that require a good weld.
- Stick Welding: Stick Welding uses an electrode coated with flux to create the weld. This is one of the most popular and oldest welding methods. You can use this method on various metals and under different conditions.
- Other Methods： There are many other welding methods, each with its specific application. For example, Flux-Cored Arc Welding is a technique similar to MIG, using a tubular wire filled with flux. People also use Submerged Arc Welding in industrial applications for thick materials.
Welding Materials – Electrodes and filler metals
- Electrodes： In welding, choosing an electrode compatible with the base metals and the welding method is essential. Electrodes are either non-consumable (as in TIG welding, where tungsten melts at a high temperature) or consumable (as in Stick and MIG, where the electrode is the filler).
- Filler Materials: The choice of filler metal depends on the type and desired properties of the joint. Filler metals come in a variety of forms, including wires and powders. The materials are chosen to match the base metal closely. The filler metal composition affects the weld’s strength, flexibility, and corrosion resistance.
Brazing VS Welding: Benefits
Benefits of Brazing
The brazing process is a prevalent method in metal fabrication. It offers several advantages, which make it the preferred choice for many applications. Brazing is a versatile method for joining dissimilar metals, and it can preserve the integrity of base metals.
The versatility of joining dissimilar metals
Brazing can join metals that are not compatible. You can join these metals without facing the metallurgical issues that might arise from welding.
Maintaining the Integrity in Base Metals
Brazing also has the advantage of preserving base metals’ original properties and strength. The base metals retain their original properties because the brazing process heats the metals below their melting point.
Welding has many advantages.
There are many advantages to welding. The strength and durability of joints and the versatility of welding are two of its most important advantages.
Joint Strength and Durability
Welding is a great way to create strong and durable joints. In contrast to mechanical fastening, welding joins base materials, usually with a filler with similar chemical and mechanical properties. This results in a bond that is often stronger than the base materials.
Wide Range of Materials Suitability
The versatility of welding stands out as a critical benefit, allowing its use on various materials, including steel, aluminum, copper, and some plastics. Different welding techniques, such as MIG TIG and Stick welding, have been developed to accommodate the properties of each material. This versatility ensures you can achieve reliable and effective joints, regardless of the base material.
Brazing VS Welding: Limitations
Limitations of brazing
Brazing has many advantages but also some limitations. It is essential to understand these limitations when selecting the best metal joining technique.
Welding Strength Compared with Other Methods
Brazing has some limitations compared to welding, primarily regarding joint strength. Brazing uses a filler material with a lower melting temperature than base metals. The resultant solid joint may withstand less stress than a weld. Welding melts the base metals, resulting in a strong joint.
Application Limitations
The nature of brazing itself also limits its application. However, brazing joints require close-fitting parts to ensure capillary action. Too large or irregular gaps may not be filled correctly, resulting in weak joints.
Welding Limitations
Although welding is a valuable manufacturing and fabrication method, it has limitations. It is essential to understand these challenges when selecting the right joining method for a project. The high skill level and potential distortion of base metals are two of the most significant welding limitations.
Technical Skill Requirements
Welding requires a high degree of skill and expertise from the welder. To achieve a high-quality weld, understanding the properties of the materials being joined and mastering the welding technique is essential. Welders need to be able to adjust parameters like heat input, welding speeds, and electrode angles on the fly to accommodate different conditions and material thicknesses.
Possible Distortion of Base Metals
The welding process uses intense heat, which can cause distortions in the base metals. The heat can distort because it causes metals in the weld area to expand and contract. This could lead to warping, twisting, or other types of deformation. Distortion is an incredibly high risk when welding large areas of thin material.
Compare Brazing and welding
Fundamental Differences
Knowing the fundamental differences between brazing and welding is essential to choosing the best joining method.
The heat source and temperature
- Brazing: This process uses a lower heat than welding. It is usually below the melting points of the base metals but above those of the filler material. This temperature range allows the filler metals to flow over the surfaces of the base metals through capillary action and join them without melting their base materials. You can braze with various heat sources, such as torches or furnaces. Induction coils and infrared lights are also possible, depending on what is needed.
- Welding: Unlike welding, which involves melting the base metal in the joint and requires significantly higher temperatures, it combines two or more metals. Heat sources such as an electric arc or laser melt the metals directly. Filler materials are often melted and added to create the weld pool. The process leads to the coalescence and creating a homogeneous, single piece after cooling.
Filler materials: What are they?
- Brazing： Filler materials are crucial in brazing. They serve to bond base metals. Filler metals are chosen based on their melting point and compatibility. The goal is to create a durable, strong joint with good thermal and electric conductivity. Filler metals must have a melting point lower than base metals to flow correctly into the joint and not cause distortion or damage.
- Welding： Filler materials can play a variety of roles in welding processes. In specific welding processes, like certain arc welding types, the electrode provides the filler rod. It is an integral part of the formation of a weld pool. Other techniques, such as gas welding, may use a separate rod for the filler material. Filler materials in welding should closely match the properties of base metals, ensuring that the weld has similar mechanical and thermomechanical properties.
Application Scenarios
The choice between brazing and welding depends on several factors. These include the materials used, the required strength for the joint, and the environment where the product will operate. This guide will assist you in understanding when to use each method.
Brazing: When and How to Use It
- Brazing to Join Dissimilar Metals: Because it doesn’t melt the base metals, brazing is perfect for joining dissimilar metals. This allows the joining of metals with different melting points or thermal expansion rates without risking distortion or stress.
- The requirement for low thermal distortion： Brazing occurs at lower temperatures than welding. This makes it suitable for applications requiring minimal thermal distortion. Because of this characteristic, brazing is a good choice for precision parts and thin-walled components.
- Needs for Electrical and Thermal Conductivity: Brazed joints can provide excellent electrical and thermal conductivity. This makes brazing the chosen method when manufacturing heat exchangers and electrical components.
- Delicate and Complex Assemblies： Brazing can be automated to mass-produce delicate and complex parts in industries such as electronics and aerospace, where precision and repetition are crucial.
Use of Welding
- High Strength Requirements： Welding provides stronger joints than brazing when the joint is required to withstand high loads or stress. Structural components of construction machinery, automotive frames, and heavy machinery often utilize welded joints.
- Joining of homogeneous materials： When joining similar metals, welding is the most effective method since it produces a homogeneous joint. This ensures the mechanical properties remain consistent.
- High-Temperature Applications: When components exposed to high temperatures are welded, the weld stays intact and strong, even under heat. This makes it ideal for engine parts and boilers.
- Cost Effectiveness for Large-Scale Projects or Thick Material: In many cases, welding is more cost-effective than brazing. This is especially true for large-scale projects or thick materials. Welding needs less filler and can often be completed more quickly.
Cost considerations
Cost considerations are crucial when deciding whether to braze or weld for a project. These costs are divided into three broad categories: initial investment, operational costs, and material and maintenance costs. Understanding the financial implications of a decision is essential for making an educated choice that meets both budgetary and technical needs.
Initial investment and operational costs
- Brazing: The initial investment in brazing equipment is lower than for welding. Capital costs may be higher for automated or high-volume brazing processes, like furnace brazing or induction welding. The price of filler materials can affect the operational costs of brazing. This is especially true for fillers based on silver or gold.
- Welding: The cost of welding equipment varies widely depending on the process. Laser welding, for example, requires a substantial investment at the beginning. The cost of welding includes using electrodes, filler materials, shielding gasses, and energy.
Materials Costs
- Brazing: The choice of filler metal significantly impacts material costs. Silver is often selected for its outstanding joining and flow properties. This leads to higher costs. Brazing is more forgiving than welding when it comes to joint preparation and cleaning, which can reduce prep and finish costs.
- Welding: The cost of welding materials depends on the type and quantity of electrodes, filler wires, and shielding gases needed. These costs vary according to the welding technique. Advanced welding techniques that require specialized materials or gases can increase these costs.
Choose between Brazing VS Welding
Considerations
There are several factors to consider when deciding whether or not to braze or weld metal parts together. At Shengen, we guide our customers through these considerations to ensure the success of their projects. Making an informed choice requires understanding the nuances surrounding material compatibility, joint strength, cost, and resources.
Material Compatibility
- Brazing： Brazing is a highly effective method for joining dissimilar metals since it does not involve melting the base material. Brazing is a great way to create leak-proof, strong joints between metals such as copper, aluminum, and steel. It is essential to choose the right filler that is compatible with base metals and suitable for the environment of the final application.
- Welding: welding is the ideal way to join similar materials or metals with compatible melting points. The welding process may alter the joint’s microstructure and affect the metals’ mechanical properties. Understanding the metallurgical effects of welding is essential for creating a joint that meets all specifications.
Strength Desired of the Joint
- Brazing： While brazing produces joints of significant strength, their strength is usually less than the base metal. The strength of a joint brazed is often more than sufficient for most applications, especially when the joint does not have to withstand high temperatures or mechanical loads.
- Welding: Welding is a method that can produce a joint that is as strong or stronger than the base metal. Welding is the best choice in critical applications where the joint must withstand high stresses, impacts, or fatigue. To achieve the desired strength, selecting the proper welding process and consumables is essential.
Cost and resource availability
- Brazing: The cost of brazing is affected by the type of filler metals and whether or not flux and controlled atmospheres are required to prevent oxidation. Brazing is more cost-effective for complex assemblies or when using expensive base materials despite the higher initial costs.
- Costs of Welding： They depend on the type of welding, consumables, and skill level the labor force needs. While welding can have higher costs initially for equipment and skilled labor, it is more cost-effective when used for large-scale productions or joining metals. When choosing between brazing or welding, considering the availability of resources and materials, including welders, is essential.
Applications Industry Specific
Many applications in the industry require brazing or welding.
Aerospace and Aviation
The brazing process is perfect for complex assemblies, such as engines or avionics. Welding offers an ideal solution when lightweight joints with high strength are essential. However, welding is preferred in areas demanding the utmost durability and strength. For example, the structure of an aircraft. Brazing or welding depends on the application. Factors like weight and stress tolerances, as well as environmental resistance, are taken into account.
Automotive Manufacturing
Both brazing and welding find applications in the automotive industry for various tasks. Brazing is especially valuable for assembling components such as radiators, fuel systems, and heat exchangers. The uniform distribution can provide leak-proof joints essential for vehicle performance and safety. In chassis and bodybuilding, the strength of the welded joint can significantly impact the vehicle’s structural integrity.
Construction and Infrastructure
The construction and infrastructure industry requires robust, durable joints that withstand environmental stress and loads. This sector relies heavily on welding in heavy machinery assembly, steel frame construction, and pipeline fabrication. It produces solid and permanent joints.
Conclusion
Understanding your project’s requirements–temperatures, materials, costs, and strength–will help you decide between brazing or welding. The proper technique is crucial when creating a delicate jewelry piece or a sturdy frame.
Do you need a reliable sheet metal parts manufacturer? Shengen is the place to go. We specialize in sheet metal laser cutting, bending, surface finish, and sheet metal welding. Reach out to Shengen Today and seek help from professionals!
FAQs:
What is more robust: a brazed joint or a welded one?
A welded joint is stronger than one that has been brazed because welding melts the base material directly, potentially creating a bond as strong as the original materials.
Is brazing suitable for all metals?
The brazing process suits various metals, including copper, brass, and stainless steel. It is also applicable to some ceramics and cast irons. Additionally, brazing can accommodate certain metals, such as titanium alloys and high-carbon steels.
Is brazing faster than welding?
For small, simple joints, welding can be quicker than brazing since the bond is usually formed in one pass. Brazing is more efficient for multi-part or complex assemblies because multiple joints braze simultaneously in a furnace.
What metals cannot be brazed or welded?
Some metals, such as refractory alloys and refractory metals like tungsten or molybdenum, have high melting points and require unique processes and environments.
More Resources:
Metal Joining Techniques – Source: Slideshare
WELDING SAFETY TIPS – Source: UTI
Brazing Materials – Source: Wikipedia
Hey, I'm Kevin Lee
For the past 10 years, I’ve been immersed in various forms of sheet metal fabrication, sharing cool insights here from my experiences across diverse workshops.
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Kevin Lee
I have over ten years of professional experience in sheet metal fabrication, specializing in laser cutting, bending, welding, and surface treatment techniques. As the Technical Director at Shengen, I am committed to solving complex manufacturing challenges and driving innovation and quality in each project.
