What is Brazing? | Skill-Lync

Skill Lync

23 Nov 202005:15

Summary

TLDRThis video from Skill Link delves into brazing, a fusion welding process distinct from traditional welding as it melts only the filler metal, not the base metal. It explores various brazing methods: torch brazing with a controlled flame, furnace brazing for mass production, dip brazing using molten baths, and braze welding focusing on filler metal joints. Advantages include joining dissimilar metals and automating high-volume production. However, brazing has limitations like lower joint strength and aesthetic mismatches due to different metal colors.

Takeaways

🔥 Brazing is a fusion welding process where only the filler metal melts, not the base metal.
🌡️ The filler metal in brazing has a melting temperature above 450°C but below the melting point of the base metal.
🔧 Torch brazing involves applying flux, using a torch to heat the joint, and adding filler wire once the temperature is suitable.
⚙️ Furnace brazing is ideal for mass production and requires parts and filler metal to be heated in a furnace to the brazing temperature.
🍲 Dip brazing uses a molten salt or metal bath for heating, with the workpiece immersed to fuse joints by capillary action.
🧰 Braze welding is similar to gas welding but only the filler metal forms the joint, as the base metal doesn't melt.
🤝 Brazing allows joining of any metal, including dissimilar metals, which is not always possible with conventional welding.
🏭 Some brazing methods, like furnace and dip brazing, can be automated for high production rates.
🔩 Brazing is suitable for joining thin parts that cannot withstand the heat of welding, such as through infrared brazing.
⚖️ While brazing has several advantages, the joints created are generally less strong than welded joints and not suitable for high-temperature operations.

Q & A

What is brazing and how does it differ from other welding processes?
-Brazing is a type of fusion welding process where only the filler metal is melted, not the base metal. It differs from other welding processes where both the base metal and the filler metal are melted together.
What is the melting temperature range for the filler metal used in brazing?
-The filler metal used in brazing has a melting temperature above 450 degrees centigrade but below the melting point of the base metal.
What are the various types of brazing mentioned in the script?
-The script mentions torch brazing, furnace brazing, dip brazing, and braze welding as the various types of brazing.
How is torch brazing performed and what is its significance?
-Torch brazing involves applying flux to the surfaces, using a torch to direct a flame towards the joint, and adding filler wire once the joint areas reach a suitable temperature. It is significant because it allows for manual control over the process, which is crucial for achieving a proper joint.
What type of flame is typically used in torch brazing and why?
-An oxygen-starved flame is typically used in torch brazing to prevent oxidation on the workpiece.
What is furnace brazing and in what type of production is it suited?
-Furnace brazing uses a furnace to supply heat for brazing and is suited for medium to high production rates, often used for mass-producing parts.
How does dip brazing work and what are its advantages?
-Dip brazing uses a molten salt bath or a molten metal bath as a heat source, where the workpiece and the brazing metal are immersed. The advantages include faster fusion of joints and the ability to join multiple joints at once.
What is the difference between braze welding and gas welding?
-In gas welding, both the base metal and the filler are melted and fused together, whereas in braze welding, the joint consists only of filler metal since the base metal does not melt.
What are some advantages of brazing compared to welding?
-Brazing allows joining of any metal, including dissimilar metals, and can be performed quickly and consistently for high production rates. It also requires less heat and power than most fusion welding processes.
What are the disadvantages of brazing as mentioned in the script?
-The disadvantages of brazing include weaker joint strength compared to welded joints, inability to join components required for high-temperature operations due to the low melting temperature of brazing metals, and potential aesthetic issues due to color mismatch between the brazing metal and the base metal.
What is the role of the worker's skill in torch brazing?
-The worker's skill is crucial in torch brazing as they must control the flame, manipulate the handheld torch, and properly judge the temperature to ensure a proper joint is obtained.

Outlines

00:00

🔥 Introduction to Brazing Techniques

This paragraph introduces brazing as a fusion welding process distinct from other welding methods because it involves melting only the filler metal, not the base metal. The filler metal, also known as brazing metal, has a melting point above 450°C but below the base metal's melting point. The video discusses various types of brazing, starting with torch brazing, which uses a flux and a torch to melt the filler wire and create a joint. The torch brazing process is manual and requires skill to control the flame and judge the temperature. Furnace brazing is highlighted as a method suitable for mass production, where parts and brazing metal are heated in a furnace to melt the brazing metal and fuse joints. Dip brazing is another technique using a molten salt or metal bath for heating, suitable for workpieces with many joints. The paragraph also mentions braze welding, which is similar to gas welding but uses only filler metal for the joint. The advantages of brazing include the ability to join any metal, including dissimilar ones, and the possibility of high production rates and automation. However, brazing has limitations such as lower joint strength compared to welding and the inability to join components for high-temperature operations due to the low melting temperature of brazing metals.

05:02

👋 Conclusion and Farewell

In this concluding paragraph, the speaker summarizes the information about brazing and expresses hope that the viewers have gained a clear understanding of the process. The speaker then bids farewell, indicating the end of the video and the anticipation of meeting the viewers in the next video. The paragraph is brief and serves as a closing remark, accompanied by background music.

Mindmap

Keywords

💡Brazing

Brazing is a type of fusion welding process where the base metal is not melted, only the filler metal is melted. This process is used to join materials, particularly those with high melting points, without altering the base metal's properties. In the video, brazing is the central theme, with various methods like torch brazing, furnace brazing, and dip brazing being discussed as specific techniques within this broader process.

💡Filler Metal

Filler metal, also known as brazing metal, is the material that melts during the brazing process to create a joint between two base metals. It has a melting temperature above 450 degrees Celsius but below the melting point of the base metal. The script mentions that the filler wire is added to the joint area once it has reached a suitable temperature, and it melts to create the joint, highlighting its crucial role in the brazing process.

💡Torch Brazing

Torch brazing is a manual brazing method where a flame from a torch is directed towards the joint area to heat it. A flux is applied to the surfaces to prevent oxidation. The script describes how an oxygen-starved flame is used to heat the joint, and once the temperature is right, the filler wire is added to create the joint, emphasizing the skill required to control the torch and judge the temperature accurately.

💡Furnace Brazing

Furnace brazing is a type of brazing that uses a furnace to supply heat for the process, suitable for mass production. The script explains that parts and brazing metal are loaded into the furnace, heated to the brazing temperature, and then the brazing metal melts to fuse the joints. This method is highlighted as being efficient for medium to high production rates and can be automated.

💡Dip Brazing

Dip brazing involves immersing the workpiece and brazing metal into a molten salt bath or a molten metal bath as a heat source. The script mentions that the molten salt bath generally contains a mixture of fluxing ingredients, while the metal bath method uses the filler material as the heating medium. This method is particularly useful for workpieces with many joints, as it allows for a faster and more efficient joining process.

💡Braze Welding

Braze welding is similar to gas welding but differs in that only the filler metal is used to create the joint, not the base metal. The script explains that in braze welding, the base metal does not melt and therefore does not fuse to the joint as in conventional fusion welding processes. This method is commonly used in repair work, such as on pipes and beams, where the base metal's integrity needs to be preserved.

💡Acetylene

Acetylene is a fuel used in torches for brazing when the filler or workpiece has a very high temperature tolerance. The script notes that acetylene burns at almost 3000 degrees Celsius, making it suitable for high-temperature brazing applications. It is an example of how the choice of fuel can impact the effectiveness of the brazing process.

💡Oxidation

Oxidation is a chemical reaction that can occur when metals are exposed to oxygen at high temperatures, which can interfere with the brazing process. The script mentions the use of an oxygen-starved flame in torch brazing to prevent oxidation on the workpiece, ensuring a clean and strong joint.

💡Capillary Action

Capillary action is the ability of a liquid to flow in narrow spaces without the assistance of external forces. In dip brazing, the script explains that the molten metal is drawn into the joint by capillary action during submersion, which aids in the joining process by ensuring the filler metal fills the joint properly.

💡Infrared Brazing

Infrared brazing is a method where an infrared lamp is used to generate heat for joining thin parts that cannot be welded. The script briefly touches on this method as an example of how brazing can be adapted for specific applications, such as joining delicate or heat-sensitive materials.

Highlights

Brazing is a fusion welding process similar to gas welding but with the base metal not melted.

The filler metal in brazing has a melting temperature above 450 degrees Celsius but below the base metal's melting point.

Torch brazing involves applying flux, using a torch to heat, and adding filler wire to create a joint.

Acetylene is used in torch brazing for materials with high temperature tolerance due to its high burning temperature.

Furnace brazing is suitable for mass production and uses a furnace to heat parts and brazing metal for joining.

Dip brazing uses a molten salt or metal bath as a heat source for joining workpieces.

In dip brazing, the molten metal is drawn into the joint by capillary action during submersion.

Braze welding is similar to gas welding but uses only filler metal for the joint, not melting the base metal.

Brazing allows joining any metal, including dissimilar metals, which is not possible with most welding types.

Furnace and dip brazing can be automated for high production rates and consistent results.

Brazing can join thin parts that cannot be welded, such as with infrared brazing using an infrared lamp.

Brazing generally requires less heat and power than most fusion welding processes.

The strength of brazed joints is generally less than that of welded joints.

Brazing metals have low melting temperatures, making them unsuitable for high-temperature operations.

Aesthetic mismatch may occur between the brazing metal and the base metal in some applications.